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Sample records for 2d antidot lattices

  1. Localization oscillation in antidot lattices

    NASA Astrophysics Data System (ADS)

    Uryu, S.; Ando, T.

    1998-06-01

    The Anderson localization in square and hexagonal antidot lattices is numerically studied with the use of a Thouless number method. It is revealed that localization is very sensitive to the aspect ratio between the antidot diameter and the lattice constant. In a hexagonal lattice, both the Thouless number and the localization length oscillate with the period equal to the Al’tshuler-Aronov-Spivak oscillation. The oscillation is quite weak in a square lattice.

  2. Numerical study of localization in antidot lattices

    NASA Astrophysics Data System (ADS)

    Uryu, Seiji; Ando, Tsuneya

    1998-10-01

    Localization effects in antidot lattices in weak magnetic fields are numerically studied with the use of a Thouless-number method. In hexagonal antidot lattices, both conductance and inverse localization length oscillate as a function of a magnetic flux with the same period as an Al'tshuler-Aronov-Spivak oscillation, in qualitative agreement with recent experiments.

  3. Ballistic Transport in Graphene Antidot Lattices.

    PubMed

    Sandner, Andreas; Preis, Tobias; Schell, Christian; Giudici, Paula; Watanabe, Kenji; Taniguchi, Takashi; Weiss, Dieter; Eroms, Jonathan

    2015-12-09

    The bulk carrier mobility in graphene was shown to be enhanced in graphene-boron nitride heterostructures. However, nanopatterning graphene can add extra damage and drastically degrade the intrinsic properties by edge disorder. Here we show that graphene embedded into a heterostructure with hexagonal boron nitride (hBN) on both sides is protected during a nanopatterning step. In this way, we can prepare graphene-based antidot lattices where the high mobility is preserved. We report magnetotransport experiments in those antidot lattices with lattice periods down to 50 nm. We observe pronounced commensurability features stemming from ballistic orbits around one or several antidots. Due to the short lattice period in our samples, we can also explore the boundary between the classical and the quantum transport regime, as the Fermi wavelength of the electrons approaches the smallest length scale of the artificial potential.

  4. Thermoelectric properties of electrostatically tunable antidot lattices

    NASA Astrophysics Data System (ADS)

    Goswami, Srijit; Siegert, Christoph; Shamim, Saquib; Pepper, Michael; Farrer, Ian; Ritchie, David A.; Ghosh, Arindam

    2010-09-01

    We report on the fabrication and characterization of a device which allows the formation of an antidot lattice (ADL) using only electrostatic gating. The antidot potential and Fermi energy of the system can be tuned independently. Well defined commensurability features in magnetoresistance as well as magnetothermopower are observed. We show that the thermopower can be used to efficiently map out the potential landscape of the ADL.

  5. Magnetic switching of nanoscale antidot lattices

    PubMed Central

    Gräfe, Joachim; Lebecki, Kristof M; Skripnik, Maxim; Haering, Felix; Schütz, Gisela; Ziemann, Paul; Goering, Eberhard; Nowak, Ulrich

    2016-01-01

    Summary We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices. PMID:27335762

  6. Altshuler-Aronov-Spivak Oscillation in Graphene Antidot lattice

    NASA Astrophysics Data System (ADS)

    Yagi, Ryuta; Sakakibara, Ryoji; Onishi, Junpei; Yagi Lab. Team

    2015-03-01

    We have observed the Altshuler-Aronov-Spivac (AAS) oscillation in triangular antidot lattice of single layer graphene. Low temperature magnetoresistance exhibited h / 2 e periodic oscillations near zero magnetic field, negative magnetoresistance, and h / e periodic (AB-type) oscillations at higher magnetic fields. Phase of the AAS oscillation was the same as those for conventional 2D electrons with negligible spin orbit interaction, showing that inter-valley scattering averaged the Berry phase effect which results in anti-localization.

  7. Critical phenomena in ferromagnetic antidot lattices

    NASA Astrophysics Data System (ADS)

    Zivieri, R.

    2016-05-01

    In this paper a quantitative theoretical formulation of the critical behavior of soft mode frequencies as a function of an applied magnetic field in two-dimensional Permalloy square antidot lattices in the nanometric range is given according to micromagnetic simulations and simple analytical calculations. The degree of softening of the two lowest-frequency modes, namely the edge mode and the fundamental mode, corresponding to the field interval around the critical magnetic field, can be expressed via numerical exponents. For the antidot lattices studied we have found that: a) the ratio between the critical magnetic field and the in-plane geometric aspect ratio and (b) the ratio between the numerical exponents of the frequency power laws of the fundamental mode and of the edge mode do not depend on the geometry. The above definitions could be extended to other types of in-plane magnetized periodic magnetic systems exhibiting soft-mode dynamics and a fourfold anisotropy.

  8. Programmability of Co-antidot lattices of optimized geometry

    PubMed Central

    Schneider, Tobias; Langer, Manuel; Alekhina, Julia; Kowalska, Ewa; Oelschlägel, Antje; Semisalova, Anna; Neudert, Andreas; Lenz, Kilian; Potzger, Kay; Kostylev, Mikhail P.; Fassbender, Jürgen; Adeyeye, Adekunle O.; Lindner, Jürgen; Bali, Rantej

    2017-01-01

    Programmability of stable magnetization configurations in a magnetic device is a highly desirable feature for a variety of applications, such as in magneto-transport and spin-wave logic. Periodic systems such as antidot lattices may exhibit programmability; however, to achieve multiple stable magnetization configurations the lattice geometry must be optimized. We consider the magnetization states in Co-antidot lattices of ≈50 nm thickness and ≈150 nm inter-antidot distance. Micromagnetic simulations were applied to investigate the magnetization states around individual antidots during the reversal process. The reversal processes predicted by micromagnetics were confirmed by experimental observations. Magnetization reversal in these antidots occurs via field driven transition between 3 elementary magnetization states – termed G, C and Q. These magnetization states can be described by vectors, and the reversal process proceeds via step-wise linear operations on these vector states. Rules governing the co-existence of the three magnetization states were empirically observed. It is shown that in an n × n antidot lattice, a variety of field switchable combinations of G, C and Q can occur, indicating programmability of the antidot lattices. PMID:28145463

  9. Programmability of Co-antidot lattices of optimized geometry

    NASA Astrophysics Data System (ADS)

    Schneider, Tobias; Langer, Manuel; Alekhina, Julia; Kowalska, Ewa; Oelschlägel, Antje; Semisalova, Anna; Neudert, Andreas; Lenz, Kilian; Potzger, Kay; Kostylev, Mikhail P.; Fassbender, Jürgen; Adeyeye, Adekunle O.; Lindner, Jürgen; Bali, Rantej

    2017-02-01

    Programmability of stable magnetization configurations in a magnetic device is a highly desirable feature for a variety of applications, such as in magneto-transport and spin-wave logic. Periodic systems such as antidot lattices may exhibit programmability; however, to achieve multiple stable magnetization configurations the lattice geometry must be optimized. We consider the magnetization states in Co-antidot lattices of ≈50 nm thickness and ≈150 nm inter-antidot distance. Micromagnetic simulations were applied to investigate the magnetization states around individual antidots during the reversal process. The reversal processes predicted by micromagnetics were confirmed by experimental observations. Magnetization reversal in these antidots occurs via field driven transition between 3 elementary magnetization states – termed G, C and Q. These magnetization states can be described by vectors, and the reversal process proceeds via step-wise linear operations on these vector states. Rules governing the co-existence of the three magnetization states were empirically observed. It is shown that in an n × n antidot lattice, a variety of field switchable combinations of G, C and Q can occur, indicating programmability of the antidot lattices.

  10. Quantum oscillation and decoherence in triangular antidot lattice

    NASA Astrophysics Data System (ADS)

    Ueki, M.; Endo, A.; Katsumoto, S.; Iye, Y.

    2004-04-01

    Quantum oscillation phenomena in triangular antidot lattice have been investigated. Altshuler-Aronov-Spivak oscillations and Aharonov-Bohm (AB)-type oscillations are observed at low magnetic field, and AB-type oscillations due to edge channels are observed in the quantum Hall regime. Measurements of the temperature dependence of these oscillations furnish information on the mechanism of decoherence in the antidot lattice, which is compared with the single ring case.

  11. Quantum interference and decoherence in hexagonal antidot lattices

    NASA Astrophysics Data System (ADS)

    Iye, Yasuhiro; Ueki, Masaaki; Endo, Akira; Katsumoto, Shingo

    2003-09-01

    The Altshuler-Aronov-Spivak (AAS) oscillations and the Aharonov-Bohm (AB) type oscillations both at low and high magnetic fields were observed in hexagonal antidot lattices fabricated from a GaAs/AlGaAs two-dimensional electron gas sample. The periodicities in the magnetic field and in the gate bias voltage, of the high field AB oscillation furnish information on the edge states localized around the antidots. The temperature dependences of these quantum oscillations are studied.

  12. Graphene antidot lattices as potential electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Liu, Lizhao; Yue, Xin; Zhao, Jijun; Cheng, Qian; Tang, Jie

    2015-05-01

    Thermodynamic stabilities and electronic properties of graphene antidot lattices with hexagonal holes were examined using density functional theory calculations and several crucial factors related to the applications of supercapacitors were discussed. For the graphene antidot lattices with different hole sizes, the formation energy per edge length is about 0.50∼0.60 eV/nm, which is comparable to that of graphene nanoribbon edges. Within a hole density of 10%, the graphene antidot lattices can maintain the excellent electronic properties of perfect graphene due to negligible intervalley scattering. Further increasing the hole density will open a band gap. Taking the potassium chloride (KCl) electrolyte as an example, we further investigated the diffusion behaviors of potassium (K) and chlorine (Cl) atoms through the graphene antidot lattices. It was shown that K and Cl atoms can go through the holes with nearly no barrier at an appropriate hole size of 0.54 nm, which gives an optimum pore diameter of ∼0.86 nm. Therefore, the excellent graphene-like electronic properties and good penetrability for ions suggest promising applications of graphene antidot lattices in the field of supercapacitors.

  13. Aharonov-Bohm-type Effects in Triangular Antidot Lattice

    NASA Astrophysics Data System (ADS)

    Iye, Yaushiro; Ueki, Masaaki; Endo, Akira; Katsumoto, Shingo

    2004-12-01

    Three kinds of Aharonov-Bohm (AB)-type oscillation have been investigated in triangular antidot lattice fabricated from a GaAs/AlGaAs two-dimensional electron gas sample. The oscillation periods of Altshuler-Aronov-Spivak (AAS) effect and AB-type effect near zero magnetic field are determined by the unit cell area, whereas those of AB-type oscillations in the quantum Hall plateau transition regime are governed by the effective area of antidot. The evolution of the high-field AB-type oscillation as a function of gate voltage gives infomation on the profile of the self-consistent potential associated with compressible edge channels formed around antidot. The temperature dependences and decoherence mechanisms of the AAS and AB-type oscillations near zero magnetic field as well as the high-field AB-type oscillation are discussed.

  14. Electronic structure and energetics of graphene antidot lattice

    NASA Astrophysics Data System (ADS)

    Sakurai, Masahiro; Saito, Susumu; Takada, Yasutami

    2012-02-01

    We have made a systematic study of the electronic structure and the energetics of graphene with periodic array of vacancy clusters (graphene antidot lattice) in the framework of the density-functional theory (DFT). We find that the electronic property of the system is well controlled by its lattice periodicity. More specifically, this system can be either metallic or semiconducting, depending on its lattice geometry. Interestingly, some of them are predicted to be direct-gap semiconductors. For example, graphene sheet with high-symmetry arrangements of periodic circle-shape vacancies always has a direct fundamental gap [1]. The DFT total-energy calculations indicate that the geometry of hole edges plays an important role in determining its stability. [1] ``Electronic properties of graphene and boron-nitride based nanostructured materials'' M. Sakurai, Y. Sakai, and S. Saito, J. Phys.: Conf. Ser. 302 (2011) 012018.

  15. Influence of lattice defects on the ferromagnetic resonance behaviour of 2D magnonic crystals

    PubMed Central

    Manzin, Alessandra; Barrera, Gabriele; Celegato, Federica; Coïsson, Marco; Tiberto, Paola

    2016-01-01

    This paper studies, from a modelling point of view, the influence of randomly distributed lattice defects (non-patterned areas and variable hole size) on the ferromagnetic resonance behaviour and spin wave mode profiles of 2D magnonic crystals based on Ni80Fe20 antidot arrays with hexagonal lattice. A reference sample is first defined via the comparison of experimental and simulated hysteresis loops and magnetoresistive curves of patterned films, prepared by self-assembly of polystyrene nanospheres. Second, a parametric analysis of the dynamic response is performed, investigating how edge, quasi-uniform and localized modes are affected by alterations of the lattice geometry and bias field amplitude. Finally, some results about the possible use of magnetic antidot arrays in frequency-based sensors for magnetic bead detection are presented, highlighting the need for an accurate control of microstructural features. PMID:26911336

  16. Influence of lattice defects on the ferromagnetic resonance behaviour of 2D magnonic crystals

    NASA Astrophysics Data System (ADS)

    Manzin, Alessandra; Barrera, Gabriele; Celegato, Federica; Coïsson, Marco; Tiberto, Paola

    2016-02-01

    This paper studies, from a modelling point of view, the influence of randomly distributed lattice defects (non-patterned areas and variable hole size) on the ferromagnetic resonance behaviour and spin wave mode profiles of 2D magnonic crystals based on Ni80Fe20 antidot arrays with hexagonal lattice. A reference sample is first defined via the comparison of experimental and simulated hysteresis loops and magnetoresistive curves of patterned films, prepared by self-assembly of polystyrene nanospheres. Second, a parametric analysis of the dynamic response is performed, investigating how edge, quasi-uniform and localized modes are affected by alterations of the lattice geometry and bias field amplitude. Finally, some results about the possible use of magnetic antidot arrays in frequency-based sensors for magnetic bead detection are presented, highlighting the need for an accurate control of microstructural features.

  17. Localization and antilocalization in InSb and InAs antidot lattices

    NASA Astrophysics Data System (ADS)

    Peters, J. A.; Chen, Hong; Pan, Yue; Guan, Yafei; Heremans, J. J.; Goel, N.; Chung, S. J.; Santos, M. B.; Van Roy, W.; Borghs, G.

    2006-08-01

    We report on the observation of localization, antilocalization and Altshuler-Aronov-Spivak (AAS) oscillations in antidot lattices patterned on high-mobility InSb/InAlSb and InAs/AlGaSb heterostructures. In addition, the antidot lattices display ballistic commensurability features. The strength of the localization peak in InSb antidot lattices decreases exponentially with temperature, with a high characteristic temperature of ∼25 K between 0.4 and 50 K. Analysis of the AAS oscillations enables the extraction of phase and spin coherence lengths in InAs.

  18. A study of periodic and aperiodic ferromagnetic antidot lattices

    NASA Astrophysics Data System (ADS)

    Bhat, Vinayak S.

    This thesis reports our study of the effect of domain wall pinning by ferromagnetic (FM) metamaterials [1] in the form of periodic antidot lattices (ADL) on spin wave spectra in the reversible regime. This study was then extended to artificial quasicrystals in the form of Penrose P2 tilings (P2T). Our DC magnetization study of these metamaterials showed reproducible and temperature dependent knee anomalies in the hysteretic regime that are due to the isolated switching of the FM segments. Our dumbbell model analysis [2] of simulated magnetization maps indicates that FM switching in P2T is nonstochastic . We have also acquired the first direct, two-dimensional images of the magnetization of Permalloy films patterned into P2T using scanning electron microscopy with polarization analysis (SEMPA). Our SEMPA images demonstrate P2T behave as geometrically frustrated networks of narrow ferromagnetic film segments having near-uniform, bipolar (Ising-like) magnetization, similar to artificial spin ices (ASI). We find the unique aperiodic translational symmetry and diverse vertex coordination of multiply-connected P2T induce a more complex spin-ice behavior driven by exchange interactions in vertex domain walls, which differs markedly from the behavior of disconnected ASI governed only by dipolar interactions. Keywords: Ferromagnetic Antidot Lattices, Metamaterials, Ferromagnetic Resonance, Artificial Quasicrystal, Artificial Spin Ice. [1] VV Kruglyak et al. "Magnonic metamaterials". In: Metamaterial, edited by X.-Y. Jiang (InTech, 2012) (2012). [2] Claudio Castelnovo, Roderich Moessner, and Shivaji L Sondhi. "Magnetic monopoles in spin ice". In: Nature 451.7174 (2008), pp. 42--45.

  19. Electrostatic modulation of periodic potentials in a two-dimensional electron gas: From antidot lattice to quantum dot lattice

    SciTech Connect

    Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam; Siegert, Christoph; Farrer, Ian; Ritchie, David A.; Pepper, Michael

    2013-12-04

    We use a dual gated device structure to introduce a gate-tuneable periodic potential in a GaAs/AlGaAs two dimensional electron gas (2DEG). Using only a suitable choice of gate voltages we can controllably alter the potential landscape of the bare 2DEG, inducing either a periodic array of antidots or quantum dots. Antidots are artificial scattering centers, and therefore allow for a study of electron dynamics. In particular, we show that the thermovoltage of an antidot lattice is particularly sensitive to the relative positions of the Fermi level and the antidot potential. A quantum dot lattice, on the other hand, provides the opportunity to study correlated electron physics. We find that its current-voltage characteristics display a voltage threshold, as well as a power law scaling, indicative of collective Coulomb blockade in a disordered background.

  20. The analyzation of 2D complicated regular polygon photonic lattice

    NASA Astrophysics Data System (ADS)

    Lv, Jing; Gao, Yuanmei

    2017-06-01

    We have numerically simulated the light intensity distribution, phase distribution, far-field diffraction of the two dimensional (2D) regular octagon and regular dodecagon lattices in detail. In addition, using the plane wave expansion (PWE) method, we numerically calculate the energy band of the two lattices. Both of the photonic lattices have the band gap. And the regular octagon lattice possesses the wide complete band gap while the regular dodecagon lattice has the incomplete gap. Moreover, we simulated the preliminary transmission image of photonic lattices. It may inspire the academic research both in light control and soliton.

  1. Effects of antidot shape on the spin wave spectra of two-dimensional Ni{sub 80}Fe{sub 20} antidot lattices

    SciTech Connect

    Mandal, Ruma; Laha, Pinaki; Das, Kaustuv; Saha, Susmita; Barman, Saswati; Raychaudhuri, A. K.; Barman, Anjan

    2013-12-23

    We show that the optically induced spin wave spectra of nanoscale Ni{sub 80}Fe{sub 20} (permalloy) antidot lattices can be tuned by changing the antidot shape. The spin wave spectra also show an anisotropy with the variation of the in-plane bias field orientation. Analyses show this is due to various quantized and extended modes, whose nature changes with the antidot shape and bias field orientation as a result of the variation of the internal magnetic field profile. The observed variation and anisotropy in the spin waves with the internal and external parameters are important for their applications in magnonic devices.

  2. Quantum computing via defect states in two-dimensional antidot lattices.

    PubMed

    Flindt, Christian; Mortensen, Niels Asger; Jauho, Antti-Pekka

    2005-12-01

    We propose a new structure suitable for quantum computing in a solid-state environment: designed defect states in antidot lattices superimposed on a two-dimensional electron gas at a semiconductor heterostructure. State manipulation can be obtained with gate control. Model calculations indicate that it is feasible to fabricate structures whose energy level structure is robust against thermal dephasing.

  3. Dirac fermions and pseudomagnetic fields in two-dimensional electron gases with triangular antidot lattices

    NASA Astrophysics Data System (ADS)

    Li, Yun-Mei; Zhou, Xiaoying; Zhang, Yan-Yang; Zhang, Dong; Chang, Kai

    2017-07-01

    We investigate theoretically the electronic properties of two-dimensional electron gases (2DEGs) with regular and distorted triangular antidot lattices. We show that the triangular antidot lattices embedded in 2DEGs behave like artificial graphene and host Dirac fermions. By introducing the Wannier representation, we obtain a tight-binding Hamiltonian including the second-nearest-neighboring hopping, which agrees well with the numerically exact solutions. Based on the tight-binding model, we find that spatially nonuniform distortions of the antidot lattices strongly modify the electronic structures, generate pseudomagnetic fields and the well-defined Landau levels. In contrast to graphene, we can design the nonuniform distortions to generate various configurations of pseudomagnetic fields. We show that the snake orbital states arise by designing the ±B pseudomagnetic field configuration. We find that the disorders of antidot lattices during fabrication would not affect the basic feature of the Dirac electrons, but they lead to a reduction in conductance in strong disorder cases.

  4. Energy spectrum of a 2D Dirac oscillator in the presence of a constant magnetic field and an antidot potential

    NASA Astrophysics Data System (ADS)

    Akcay, Huseyin; Sever, Ramazan

    2016-07-01

    We investigate the energy spectrum and the corresponding eigenfunctions of a 2D Dirac oscillator confined by an antidot potential in the presence of a magnetic field and Aharonov-Bohm flux field. Analytical solutions are obtained and compared with the results of the Schrödinger equation found in the literature. Further, the dependence of the spectrum on the magnetic quantum number and on the repulsive potential is discussed.

  5. Angle-resolved spin wave band diagrams of square antidot lattices studied by Brillouin light scattering

    SciTech Connect

    Gubbiotti, G.; Tacchi, S.; Madami, M.; Carlotti, G.; Ding, J.; Adeyeye, A. O.

    2015-06-29

    The Brillouin light scattering technique has been exploited to study the angle-resolved spin wave band diagrams of squared Permalloy antidot lattice. Frequency dispersion of spin waves has been measured for a set of fixed wave vector magnitudes, while varying the wave vector in-plane orientation with respect to the applied magnetic field. The magnonic band gap between the two most dispersive modes exhibits a minimum value at an angular position, which exclusively depends on the product between the selected wave vector magnitude and the lattice constant of the array. The experimental data are in very good agreement with predictions obtained by dynamical matrix method calculations. The presented results are relevant for magnonic devices where the antidot lattice, acting as a diffraction grating, is exploited to achieve multidirectional spin wave emission.

  6. Universal rule on chirality-dependent bandgaps in graphene antidot lattices.

    PubMed

    Liu, Xiaofei; Zhang, Zhuhua; Guo, Wanlin

    2013-04-22

    Graphene with periodically patterned antidots has attracted intense research attention as it represents a facile route to open a bandgap for graphene electronics. However, not all graphene antidot lattices (GALs) can open a bandgap and a guiding rule is missing. Here, through systematic first-principles calculations, it is found that bandgaps in triangular GALs are surprisingly well defined by a chirality vector R = n a1 + ma2 connecting two neighboring antidots, where a1 and a2 are the basis vectors of graphene. The bandgap opens in the GALs with (n-m)mod3 = 0 but remains closed in those with (n-m)mod3 = ±1, reminiscent of the gap-chirality rule in carbon nanotubes. Remarkably, the gap value in GALs allows ample modulation by adjusting the length of chirality vectors, shape and size of the antidots. The gap-chirality relation in GALs stems from the chirality-dependent atomic structures of GALs as revealed by a super-atom model as well as Clar sextet analyses. This chirality-dependent bandgap is further shown to be a generic behavior in any parallelogram GAL and thus serves as an essential stepping stone for experimenters to realize graphene devices by antidot engineering.

  7. Beam-Plasma Instabilities in a 2D Yukawa Lattice

    SciTech Connect

    Kyrkos, S.; Kalman, G. J.; Rosenberg, M.

    2009-06-05

    We consider a 2D Yukawa lattice of grains, with a beam of other charged grains moving in the lattice plane. In contrast to Vlasov plasmas, where the electrostatic instability excited by the beam is only longitudinal, here both longitudinal and transverse instabilities of the lattice phonons can develop. We determine and compare the transverse and longitudinal growth rates. The growth rate spectrum in wave number space exhibits remarkable gaps where no instability can develop. Depending on the system parameters, the transverse instability can be selectively excited.

  8. Magnetization reversal mechanism in patterned (square to wave-like) Py antidot lattices

    NASA Astrophysics Data System (ADS)

    Tahir, N.; Zelent, M.; Gieniusz, R.; Krawczyk, M.; Maziewski, A.; Wojciechowski, T.; Ding, J.; Adeyeye, A. O.

    2017-01-01

    The effects of shape and geometry of antidot (square, bi-component, and wave-like) lattices (ADLs) on the magnetization reversal processes and magnetic anisotropy has been systematically investigated by magneto-optical Kerr effect based microscopy. Our experimental results were reproduced by micromagnetic simulations, which highlight the qualitative agreement with the experimental results. We have demonstrated that a small antidot in the center of a unit cell in the square ADL is sufficient to induce additional easy axes with large coercive fields. In wave-like patterns, narrow channels connecting smaller and larger antidots (bi-component ADL) further drastically change the anisotropy map, creating the high coercive fields along a wide angular range (90°) of directions parallel to the channels. In simulated results, we have observed formation of periodic domain structures in all ADLs, however, in the case of a wave-like pattern it is most regular and moreover two different periodic patterns are stabilized at different applied magnetic field values. The formation of 360° domain walls were also observed in wave-like ADL where these domains are formed along the lines connecting adjacent larger and smaller antidots, perpendicular to the channels. These findings point out the possibility of exploiting ADLs with complex unit cells in magnonic or spintronic applications.

  9. 2D Lattices of Ferromagnetic Nanoparticles as Supermagnetics

    DTIC Science & Technology

    1999-06-18

    Supermagnetics DISTRIBUTION: Approved for public release, distribution unlimited Availability: Hard copy only. This paper is part of the following report: TITLE...Technology" OAN.01 i St Petersburg, Russia, June 14-18, 1999 © 1999 loffe Institute 2D lattices of ferromagnetic nanoparticles as supermagnetics A. A...temperature the system became ordered due to the dipole interaction of particles. Such a state of the system was defined as supermagnetic [ ]. The critical

  10. Substrate-assisted 2D DNA lattices and algorithmic lattices from single-stranded tiles.

    PubMed

    Kim, Junghoon; Ha, Tai Hwan; Park, Sung Ha

    2015-08-07

    We present a simple route to circumvent kinetic traps which affect many types of DNA nanostructures in their self-assembly process. Using this method, a new 2D DNA lattice made up of short, single-stranded tile (SST) motifs was created. Previously, the growth of SST DNA assemblies was restricted to 1D (tubes and ribbons) or finite-sized 2D (molecular canvases). By utilizing the substrate-assisted growth method, sets of SSTs were designed as unit cells to self-assemble into periodic and aperiodic 2D lattices which continuously grow both along and orthogonal to the helical axis. Notably, large-scale (∼1 μm(2)) fully periodic 2D lattices were fabricated using a minimum of just 2 strand species. Furthermore, the ability to create 2D lattices from a few motifs enables certain rules to be encoded into these SSTs to carry out algorithmic self-assembly. A set of these motifs was designed to execute simple 1-input 1-output COPY and NOT algorithms, the space-time manifestations which were aperiodic 2D algorithmic SST lattices. The methodology presented here can be straightforwardly applied to other motifs which fall into this type of kinetic trap to create novel DNA crystals.

  11. Interplay between Anderson and Stark Localization in 2D Lattices

    SciTech Connect

    Kolovsky, A. R.

    2008-11-07

    This Letter studies the dynamics of a quantum particle in 2D lattices with on-site disorder in the presence of a static field. It is shown that the particle is localized along the field direction, while in the orthogonal direction to the field it shows diffusive dynamics for algebraically large times. For weak disorder an analytical expression for the diffusion coefficient is obtained by mapping the problem to a band random matrix. This expression is confirmed by numerical simulations of the particle's dynamics, which also indicate the existence of a universal equation for the diffusion coefficient, valid for an arbitrary disorder strength.

  12. Tunable metamaterial response of a Ni80Fe20 antidot lattice for spin waves

    NASA Astrophysics Data System (ADS)

    Neusser, S.; Bauer, H. G.; Duerr, G.; Huber, R.; Mamica, S.; Woltersdorf, G.; Krawczyk, M.; Back, C. H.; Grundler, D.

    2011-11-01

    All-electrical spin-wave spectroscopy and frequency-resolved magneto-optical Kerr-effect measurements are combined to study spin waves propagating through a magnetic antidot lattice nanopatterned from a Ni80Fe20 thin film. Spin waves are injected from a plain film into the antidot lattice and the transmission across the interface is explored in detail for different wavelengths. We find that spin waves with a wavelength much greater than the lattice periodicity are not described well by recently discussed approaches. Instead the spin-wave dispersion is consistent with an effective magnetization smaller than the saturation magnetization measured on the unstructured ferromagnetic material. Consistently, we find that the transmission coefficients are modeled well by assuming an effectively continuous metamaterial for spin waves characterized by the reduced magnetization. The experimental data and interpretation are substantiated theoretically using the plane-wave method and micromagnetic modeling. The results are interesting for the development of frequency-selective mirrors in magnonics through lateral nanopatterning.

  13. New edge magnetoplasmon interference like photovoltage oscillations and their amplitude enhancement in the presence of an antidot lattice

    SciTech Connect

    Bisotto, I.; Portal, J.-C.; Brown, D.; Wieck, A. D.

    2015-11-15

    We present new photovoltage oscillation in a pure two dimensional electron gas (2DEG) and in the presence of circular or semicircular antidot lattices. Results were interpreted as EMPs-like photovoltage oscillations. We observed and explained the photovoltage oscillation amplitude enhancement in the presence of an antidot lattice with regard to the pure 2DEG. The microwave frequency excitation range is 139 – 350 GHz. The cyclotron and magnetoplasmon resonances take place in the magnetic field range 0.4 – 0.8 T. This original experimental condition allows edge magnetoplasmons EMPs interference like observation at low magnetic field, typically B < B{sub c} where B{sub c} is the magnetic field at which the cyclotron resonance takes place. The different oscillation periods observed and their microwave frequency dependence were discussed. For 139 and 158 GHz microwave excitation frequencies, a unique EMPs-like interference period was found in the presence of antidots whereas two periods were extracted for 295 or 350 GHz. An explanation of this effect is given taking account of strong electron interaction with antidot at low magnetic field. Indeed, electrons involved in EMPs like phenomenon interact strongly with antidots when electron cyclotron orbits are larger than or comparable to the antidot diameter.

  14. Algebraic signal processing theory: 2-D spatial hexagonal lattice.

    PubMed

    Pünschel, Markus; Rötteler, Martin

    2007-06-01

    We develop the framework for signal processing on a spatial, or undirected, 2-D hexagonal lattice for both an infinite and a finite array of signal samples. This framework includes the proper notions of z-transform, boundary conditions, filtering or convolution, spectrum, frequency response, and Fourier transform. In the finite case, the Fourier transform is called discrete triangle transform. Like the hexagonal lattice, this transform is nonseparable. The derivation of the framework makes it a natural extension of the algebraic signal processing theory that we recently introduced. Namely, we construct the proper signal models, given by polynomial algebras, bottom-up from a suitable definition of hexagonal space shifts using a procedure provided by the algebraic theory. These signal models, in turn, then provide all the basic signal processing concepts. The framework developed in this paper is related to Mersereau's early work on hexagonal lattices in the same way as the discrete cosine and sine transforms are related to the discrete Fourier transform-a fact that will be made rigorous in this paper.

  15. Magnetic response of aperiodic wire networks based on Fibonacci distortions of square antidot lattices

    NASA Astrophysics Data System (ADS)

    Farmer, B.; Bhat, V. S.; Sklenar, J.; Teipel, E.; Woods, J.; Ketterson, J. B.; Hastings, J. T.; De Long, L. E.

    2015-05-01

    The static and dynamic magnetic responses of patterned ferromagnetic thin films are uniquely altered in the case of aperiodic patterns that retain long-range order (e.g., quasicrystals). We have fabricated permalloy wire networks based on periodic square antidot lattices (ADLs) distorted according to an aperiodic Fibonacci sequence applied to two lattice translations, d1 = 1618 nm and d2 = 1000 nm. The wire segment thickness is fixed at t = 25 nm, and the width W varies from 80 to 510 nm. We measured the DC magnetization between room temperature and 5 K. Room-temperature, narrow-band (9.7 GHz) ferromagnetic resonance (FMR) spectra were acquired for various directions of applied magnetic field. The DC magnetization curves exhibited pronounced step anomalies and plateaus that signal flux closure states. Although the Fibonacci distortion breaks the fourfold symmetry of a finite periodic square ADL, the FMR data exhibit fourfold rotational symmetry with respect to the applied DC magnetic field direction.

  16. Artificial Gauge Field and Topological Phase in a Conventional Two-dimensional Electron Gas with Antidot Lattices

    PubMed Central

    Shi, Likun; Lou, Wenkai; Cheng, F.; Zou, Y. L.; Yang, Wen; Chang, Kai

    2015-01-01

    Based on the Born-Oppemheimer approximation, we divide the total electron Hamiltonian in a spin-orbit coupled system into the slow orbital motion and the fast interband transition processes. We find that the fast motion induces a gauge field on the slow orbital motion, perpendicular to the electron momentum, inducing a topological phase. From this general designing principle, we present a theory for generating artificial gauge field and topological phase in a conventional two-dimensional electron gas embedded in parabolically graded GaAs/InxGa1−xAs/GaAs quantum wells with antidot lattices. By tuning the etching depth and period of the antidot lattices, the band folding caused by the antidot potential leads to the formation of minibands and band inversions between neighboring subbands. The intersubband spin-orbit interaction opens considerably large nontrivial minigaps and leads to many pairs of helical edge states in these gaps. PMID:26471126

  17. Artificial Gauge Field and Topological Phase in a Conventional Two-dimensional Electron Gas with Antidot Lattices

    NASA Astrophysics Data System (ADS)

    Shi, Likun; Lou, Wenkai; Cheng, F.; Zou, Y. L.; Yang, Wen; Chang, Kai

    2015-10-01

    Based on the Born-Oppemheimer approximation, we divide the total electron Hamiltonian in a spin-orbit coupled system into the slow orbital motion and the fast interband transition processes. We find that the fast motion induces a gauge field on the slow orbital motion, perpendicular to the electron momentum, inducing a topological phase. From this general designing principle, we present a theory for generating artificial gauge field and topological phase in a conventional two-dimensional electron gas embedded in parabolically graded GaAs/InxGa1-xAs/GaAs quantum wells with antidot lattices. By tuning the etching depth and period of the antidot lattices, the band folding caused by the antidot potential leads to the formation of minibands and band inversions between neighboring subbands. The intersubband spin-orbit interaction opens considerably large nontrivial minigaps and leads to many pairs of helical edge states in these gaps.

  18. Mapping degenerate vortex states in a kagome lattice of elongated antidots via scanning Hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Xue, C.; Ge, J.-Y.; He, A.; Zharinov, V. S.; Moshchalkov, V. V.; Zhou, Y. H.; Silhanek, A. V.; Van de Vondel, J.

    2017-07-01

    We investigate the degeneracy of the superconducting vortex matter ground state by directly visualizing the vortex configurations in a kagome lattice of elongated antidots via scanning Hall probe microscopy. The observed vortex patterns, at specific applied magnetic fields, are in good agreement with the configurations obtained using time-dependent Ginzburg-Landau simulations. Both results indicate that the long-range interaction in this nanostructured superconductor is unable to lift the degeneracy between different vortex states and the pattern formation is mainly ruled by the nearest-neighbor interaction. This simplification makes it possible to identify a set of simple rules characterizing the vortex configurations. We demonstrate that these rules can explain both the observed vortex distributions and the magnetic-field-dependent degree of degeneracy.

  19. Theoretical study on electronic properties of MoS{sub 2} antidot lattices

    SciTech Connect

    Shao, Li; Chen, Guangde; Ye, Honggang Wu, Yelong; Niu, Haibo; Zhu, Youzhang

    2014-09-21

    Motivated by the state of the art method for etching hexagonal array holes in molybdenum disulfide (MoS{sub 2}), the electronic properties of MoS{sub 2} antidot lattices (MoS{sub 2}ALs) with zigzag edge were studied with first-principles calculations. Monolayer MoS{sub 2}ALs are semiconducting and the band gaps converge to constant values as the supercell area increases, which can be attributed to the edge effect. Multilayer MoS{sub 2}ALs and chemical adsorbed MoS{sub 2}ALs by F atoms show metallic behavior, while the structure adsorbed with H atoms remains to be semiconducting with a tiny bandgap. Our results show that forming periodically repeating structures in MoS{sub 2} can develop a promising technique for engineering nano materials and offer new opportunities for designing MoS{sub 2}-based nanoscale electronic devices and chemical sensors.

  20. Effect of substrate rotation on domain structure and magnetic relaxation in magnetic antidot lattice arrays

    SciTech Connect

    Mallick, Sougata; Mallik, Srijani; Bedanta, Subhankar

    2015-08-28

    Microdimensional triangular magnetic antidot lattice arrays were prepared by varying the speed of substrate rotation. The pre-deposition patterning has been performed using photolithography technique followed by a post-deposition lift-off. Surface morphology taken by atomic force microscopy depicted that the growth mechanism of the grains changes from chain like formation to island structures due to the substrate rotation. Study of magnetization reversal via magneto optic Kerr effect based microscopy revealed reduction of uniaxial anisotropy and increase in domain size with substrate rotation. The relaxation measured under constant magnetic field becomes faster with rotation of the substrate during deposition. The nature of relaxation for the non-rotating sample can be described by a double exponential decay. However, the relaxation for the sample with substrate rotation is well described either by a double exponential or a Fatuzzo-Labrune like single exponential decay, which increases in applied field.

  1. All-electrical detection of spin dynamics in magnetic antidot lattices by the inverse spin Hall effect

    SciTech Connect

    Jungfleisch, Matthias B.; Zhang, Wei; Ding, Junjia; Jiang, Wanjun; Sklenar, Joseph; Pearson, John E.; Ketterson, John B.; Hoffmann, Axel

    2016-02-03

    The understanding of spin dynamics in laterally confined structures on sub-micron length scales has become a significant aspect of the development of novel magnetic storage technologies. Numerous ferromagnetic resonance measurements, optical characterization by Kerr microscopy and Brillouin light scattering spectroscopy and x-ray studies were carried out to detect the dynamics in patterned magnetic antidot lattices. Here, we investigate Oersted-field driven spin dynamics in rectangular Ni80Fe20/Pt antidot lattices with different lattice parameters by electrical means. When the system is driven to resonance, a dc voltage across the length of the sample is detected that changes its sign upon field reversal, which is in agreement with a rectification mechanism based on the inverse spin Hall effect. Furthermore, we show that the voltage output scales linearly with the applied microwave drive in the investigated range of powers. Lastly, our findings have direct implications on the development of engineered magnonics applications and devices.

  2. Tunable spin wave spectra in two-dimensional Ni{sub 80}Fe{sub 20} antidot lattices with varying lattice symmetry

    SciTech Connect

    Mandal, R.; Barman, S.; Saha, S.; Barman, A.; Otani, Y.

    2015-08-07

    Ferromagnetic antidot lattices are important systems for magnetic data storage and magnonic devices, and understanding their magnetization dynamics by varying their structural parameters is an important problems in magnetism. Here, we investigate the variation in spin wave spectrum in two-dimensional nanoscale Ni{sub 80}Fe{sub 20} antidot lattices with lattice symmetry. By varying the bias magnetic field values in a broadband ferromagnetic resonance spectrometer, we observed a stark variation in the spin wave spectrum with the variation of lattice symmetry. The simulated mode profiles showed further difference in the spatial nature of the modes between different lattices. While for square and rectangular lattices extended modes are observed in addition to standing spin wave modes, all modes in the hexagonal, honeycomb, and octagonal lattices are either localized or standing waves. In addition, the honeycomb and octagonal lattices showed two different types of modes confined within the honeycomb (octagonal) units and between two such consecutive units. Simulated internal magnetic fields confirm the origin of such a wide variation in the frequency and spatial nature of the spin wave modes. The tunability of spin waves with the variation of lattice symmetry is important for the design of future magnetic data storage and magnonic devices.

  3. Broad-band FMR study of ferromagnetic thin films patterned with antidot lattices

    NASA Astrophysics Data System (ADS)

    Bhat, V.; Woods, J.; De Long, L. E.; Hastings, J. T.; Metlushko, V. V.; Rivkin, K.; Heinonen, O.; Sklenar, J.; Ketterson, J. B.

    2012-09-01

    Previous ferromagnetic resonance (FMR) studies of ferromagnetic (FM) thin films patterned with antidot (AD) arrays have generally avoided the low-field, hysteretic regime that is dominated by irreversible domain wall (DW) dynamics in unpatterned films. Moreover, FM vortices have not yet been identified and systematically studied in films patterned with AD lattices (ADLs). We have studied DC magnetization and broad-band FMR data for permalloy thin films of thickness t ≈ 25 nm, patterned with square lattices of square-shaped AD of width D and separation d = 1000 nm. We observe highly reproducible magnetic hysteresis curves and FMR spectra in the low-field reversal regime (i.e., applied magnetic fields H < HC, where HC is the coercive field), which indicates the ADL enforces a reproducible evolution of spin textures compared to the more random behavior of DW evolution in unpatterned films. The width of the reversal regime (2HC) and the field separation between observed FMR modes increases with D for a fixed separation d. Our micromagnetic simulations suggest these effects are consequences of both edge pinning of moments by individual AD, or DW pinning by the extended ADL, which involves two distinct length scales L ≈ d and L ≫ d, respectively. FM vortices are observed in our simulations, and their stability sensitively depends upon the AD size and applied magnetic field history.

  4. Optically induced spin wave dynamics in [Co/Pd]{sub 8} antidot lattices with perpendicular magnetic anisotropy

    SciTech Connect

    Pal, S.; Das, K.; Barman, A.; Klos, J. W.; Gruszecki, P.; Krawczyk, M.; Hellwig, O.

    2014-10-20

    We present an all-optical time-resolved measurement of spin wave (SW) dynamics in a series of antidot lattices based on [Co(0.75 nm)/Pd(0.9 nm)]{sub 8} multilayer (ML) systems with perpendicular magnetic anisotropy. The spectra depend significantly on the areal density of the antidots. The observed SW modes are qualitatively reproduced by the plane wave method. The interesting results found in our measurements and calculations at small lattice constants can be attributed to the increase of areal density of the shells with modified magnetic properties probably due to distortion of the regular ML structure by the Ga ion bombardment and to increased coupling between localized modes. We propose and discuss the possible mechanisms for this coupling including exchange interaction, tunnelling, and dipolar interactions.

  5. A quest for 2D lattice materials for actuation

    NASA Astrophysics Data System (ADS)

    Pronk, T. N.; Ayas, C.; Tekõglu, C.

    2017-08-01

    In the last two decades, most of the studies in shape morphing technology have focused on the Kagome lattice materials, which have superior properties such as in-plane isotropy, high specific stiffness and strength, and low energy requirement for actuation of its members. The Kagome lattice is a member of the family of semi-regular tessellations of the plane. Two fundamental questions naturally arise: i-) What makes a lattice material suitable for actuation? ii-) Are there other tessellations more effective than the Kagome lattice for actuation? The present paper tackles both questions, and provides a clear answer to the first one by comparing an alternative lattice material, the hexagonal cupola, with the Kagome lattice in terms of mechanical/actuation properties. The second question remains open, but, hopefully easier to challenge owing to a newly-discovered criterion: for an n-dimensional (n = 2 , 3) in-plane isotropic lattice material to be suitable for actuation, its pin-jointed equivalent must obey the generalised Maxwell's rule, and must possess M = 3(n - 1) non strain-producing finite kinematic mechanisms.

  6. Hofstadter butterflies and magnetically induced band-gap quenching in graphene antidot lattices

    NASA Astrophysics Data System (ADS)

    Pedersen, Jesper Goor; Pedersen, Thomas Garm

    2013-06-01

    We study graphene antidot lattices (GALs) in magnetic fields. Using a tight-binding model and a recursive Green's function technique that we extend to deal with periodic structures, we calculate Hofstadter butterflies of GALs. We compare the results to those obtained in a simpler gapped graphene model. A crucial difference emerges in the behavior of the lowest Landau level, which in a gapped graphene model is independent of magnetic field. In stark contrast to this picture, we find that in GALs the band gap can be completely closed by applying a magnetic field. While our numerical simulations can only be performed on structures much smaller than can be experimentally realized, we find that the critical magnetic field for which the gap closes can be directly related to the ratio between the cyclotron radius and the neck width of the GAL. In this way, we obtain a simple scaling law for extrapolation of our results to more realistically sized structures and find resulting quenching magnetic fields that should be well within reach of experiments.

  7. Lattice Boltzmann Equation On a 2D Rectangular Grid

    NASA Technical Reports Server (NTRS)

    Bouzidi, MHamed; DHumieres, Dominique; Lallemand, Pierre; Luo, Li-Shi; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    We construct a multi-relaxation lattice Boltzmann model on a two-dimensional rectangular grid. The model is partly inspired by a previous work of Koelman to construct a lattice BGK model on a two-dimensional rectangular grid. The linearized dispersion equation is analyzed to obtain the constraints on the isotropy of the transport coefficients and Galilean invariance for various wave propagations in the model. The linear stability of the model is also studied. The model is numerically tested for three cases: (a) a vortex moving with a constant velocity on a mesh periodic boundary conditions; (b) Poiseuille flow with an arbitrasy inclined angle with respect to the lattice orientation: and (c) a cylinder &symmetrically placed in a channel. The numerical results of these tests are compared with either analytic solutions or the results obtained by other methods. Satisfactory results are obtained for the numerical simulations.

  8. Calabi-Yau geometry and electrons on 2d lattices

    NASA Astrophysics Data System (ADS)

    Hatsuda, Yasuyuki; Sugimoto, Yuji; Xu, Zhaojie

    2017-04-01

    The B-model approach of topological string theory leads to difference equations by quantizing algebraic mirror curves. It is known that these quantum mechanical systems are solved by the refined topological strings. Recently, it was pointed out that the quantum eigenvalue problem for a particular Calabi-Yau manifold, known as local F0 , is closely related to the Hofstadter problem for electrons on a two-dimensional square lattice. In this paper, we generalize this idea to a more complicated Calabi-Yau manifold. We find that the local B3 geometry, which is a three-point blow-up of local P2 , is associated with electrons on a triangular lattice. This correspondence allows us to use known results in condensed matter physics to investigate the quantum geometry of the toric Calabi-Yau manifold.

  9. Lattice Formulation of 2D SQCD with exact supersymmetry

    SciTech Connect

    Sugino, Fumihiko

    2008-11-23

    We construct a lattice model for two-dimensional N = (2,2) supersymmetric QCD (SQCD), with the matter multiplets belonging to the fundamental or anti-fundamental representation of the gauge group U(N) or SU(N). The construction is based on the topological field theory (twisted supercharge) formulation and exactly preserves one supercharge. In order to avoid the species doublers of the matter multiplets, we introduce the Wilson terms and the model is defined for the case of the number of the fundamental matters (n{sub +}) equal to that of the anti-fundamental matters (n{sub -}). If some of the matter multiplets decouple from the theory by sending the corresponding anti-holomorphic twisted masses to the infinity, we can analyze the general n{sub +}{ne}n{sub -} case, although the lattice model is defined for n{sub +} = n{sub -}. By computing the anomaly of the U(1){sub A} R-symmetry in the lattice perturbation, we see that the decoupling is achieved and the anomaly for n{sub +}{ne}n{sub -} is correctly obtained.

  10. Quantum spin Hall phase in 2D trigonal lattice

    PubMed Central

    Wang, Z. F.; Jin, Kyung-Hwan; Liu, Feng

    2016-01-01

    The quantum spin Hall (QSH) phase is an exotic phenomena in condensed-matter physics. Here we show that a minimal basis of three orbitals (s, px, py) is required to produce a QSH phase via nearest-neighbour hopping in a two-dimensional trigonal lattice. Tight-binding model analyses and calculations show that the QSH phase arises from a spin–orbit coupling (SOC)-induced s–p band inversion or p–p bandgap opening at Brillouin zone centre (Γ point), whose topological phase diagram is mapped out in the parameter space of orbital energy and SOC. Remarkably, based on first-principles calculations, this exact model of QSH phase is shown to be realizable in an experimental system of Au/GaAs(111) surface with an SOC gap of ∼73 meV, facilitating the possible room-temperature measurement. Our results will extend the search for substrate supported QSH materials to new lattice and orbital types. PMID:27599580

  11. Quantum spin Hall phase in 2D trigonal lattice

    DOE PAGES

    Wang, Z. F.; Jin, Kyung -Hwan; Liu, Feng

    2016-09-07

    The quantum spin Hall (QSH) phase is an exotic phenomena in condensed-matter physics. Here we show that a minimal basis of three orbitals (s, px, py) is required to produce a QSH phase via nearest-neighbour hopping in a two-dimensional trigonal lattice. Tight-binding model analyses and calculations show that the QSH phase arises from a spin–orbit coupling (SOC)-induced s–p band inversion or p–p bandgap opening at Brillouin zone centre (Γ point), whose topological phase diagram is mapped out in the parameter space of orbital energy and SOC. Remarkably, based on first-principles calculations, this exact model of QSH phase is shown tomore » be realizable in an experimental system of Au/GaAs(111) surface with an SOC gap of ~73 meV, facilitating the possible room-temperature measurement. Finally, our results will extend the search for substrate supported QSH materials to new lattice and orbital types.« less

  12. Quantum spin Hall phase in 2D trigonal lattice

    SciTech Connect

    Wang, Z. F.; Jin, Kyung -Hwan; Liu, Feng

    2016-09-07

    The quantum spin Hall (QSH) phase is an exotic phenomena in condensed-matter physics. Here we show that a minimal basis of three orbitals (s, px, py) is required to produce a QSH phase via nearest-neighbour hopping in a two-dimensional trigonal lattice. Tight-binding model analyses and calculations show that the QSH phase arises from a spin–orbit coupling (SOC)-induced s–p band inversion or p–p bandgap opening at Brillouin zone centre (Γ point), whose topological phase diagram is mapped out in the parameter space of orbital energy and SOC. Remarkably, based on first-principles calculations, this exact model of QSH phase is shown to be realizable in an experimental system of Au/GaAs(111) surface with an SOC gap of ~73 meV, facilitating the possible room-temperature measurement. Finally, our results will extend the search for substrate supported QSH materials to new lattice and orbital types.

  13. Quasiparticle Spectrum of 2-d Dirac Vortices in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Haddad, Laith

    2009-10-01

    Bose-Einstein condensates in a honeycomb optical lattice are described by a nonlinear Dirac equaton (NLDE) in the long wavelength, mean field limit [1]. The upper and lower two-spinor equations decouple and superficially resemble the equations of previously studied NLDE's such as the Soler model for extended fermions. Although much work has been done on NLDE's, the bulk of the literature deals with models with Poincare invariant nonlinearites. In contrast our equations break Poincare symmetry providing an opportunity to study phenomenological models in cosmology and particle physics where this symmetry is not manifest. We obtain and classify localized solutions to our equations for both repulsive and attractive contact interactions. We also derive analogs of the Bogoliubov-de Gennes equations for the lattice and use these to study the stability and low energy spectrum of our solutions showing the existence of stable exotic structures such as vortices with fractional statistics.[4pt] [1] L. H. Haddad and L. D. Carr, ``The Nonlinear Dirac Equation in Bose-Einstein Condensates: Foundation and Symmetries,'' Physica D: Nonlinear Phenomena, v. 238, p. 1413 (2009). http://arxiv.org/pdf/0803.3039v1

  14. All-electrical detection of spin dynamics in magnetic antidot lattices by the inverse spin Hall effect

    DOE PAGES

    Jungfleisch, Matthias B.; Zhang, Wei; Ding, Junjia; ...

    2016-02-03

    The understanding of spin dynamics in laterally confined structures on sub-micron length scales has become a significant aspect of the development of novel magnetic storage technologies. Numerous ferromagnetic resonance measurements, optical characterization by Kerr microscopy and Brillouin light scattering spectroscopy and x-ray studies were carried out to detect the dynamics in patterned magnetic antidot lattices. Here, we investigate Oersted-field driven spin dynamics in rectangular Ni80Fe20/Pt antidot lattices with different lattice parameters by electrical means. When the system is driven to resonance, a dc voltage across the length of the sample is detected that changes its sign upon field reversal, whichmore » is in agreement with a rectification mechanism based on the inverse spin Hall effect. Furthermore, we show that the voltage output scales linearly with the applied microwave drive in the investigated range of powers. Lastly, our findings have direct implications on the development of engineered magnonics applications and devices.« less

  15. 2D mapping of texture and lattice parameters of dental enamel.

    PubMed

    Al-Jawad, Maisoon; Steuwer, Axel; Kilcoyne, Susan H; Shore, Roger C; Cywinski, Robert; Wood, David J

    2007-06-01

    We have used synchrotron X-ray diffraction to study the texture and the change in lattice parameter as a function of position in a cross section of human dental enamel. Our study is the first to map changes in preferred orientation and lattice parameter as a function of position within enamel across a whole tooth section with such high resolution. Synchrotron X-ray diffraction with a micro-focused beam spot was used to collect two-dimensional (2D) diffraction images at 150 microm spatial resolution over the entire tooth crown. Contour maps of the texture and lattice parameter distribution of the hydroxyapatite phase were produced from Rietveld refinement of diffraction patterns generated by azimuthally sectioning and integrating the 2D images. The 002 Debye ring showed the largest variation in intensity. This variation is indicative of preferred orientation. Areas of high crystallite alignment on the tooth cusps match the expected biting surfaces. Additionally we found a large variation in lattice parameter when travelling from the enamel surface to the enamel-dentine junction. We believe this to be due to a change in the chemical composition within the tooth. The results provide a new insight on the texture and lattice parameter profiles within enamel.

  16. 2D Superexchange-mediated magnetization dynamics in an optical lattice

    NASA Astrophysics Data System (ADS)

    Goldschmidt, Elizabeth; Brown, Roger; Wyllie, Robert; Koller, Silvio; Foss-Feig, Michael; Porto, Trey

    2015-05-01

    The interplay of magnetic exchange interactions and tunneling underlies many complex quantum phenomena observed in real materials. We study nonequilibrium magnetization dynamics in an extended 2D system by loading effective spin-1/2 bosons into a spin-dependent optical lattice, and we use the lattice to separately control the resonance conditions for tunneling and superexchange. After preparing a nonequilibrium antiferromagnetically ordered state, we observe relaxation dynamics governed by two well-separated rates, which scale with the underlying Hamiltonian parameters associated with superexchange and tunneling. Remarkably, with tunneling off-resonantly suppressed, we are able to observe superexchange-dominated dynamics over two orders of magnitude in magnetic coupling strength, despite the presence of vacancies. In this regime, the measured timescales are in agreement with simple theoretical estimates, but the detailed dynamics of this 2D, strongly-correlated, and far-from-equilibrium quantum system remain out of reach of current computational techniques. Now at Georgia Tech Research Institute.

  17. 2D Unstructured Finite Volume Lattice Boltzmann Model for Flow with Complex Geometric Boundaries

    NASA Astrophysics Data System (ADS)

    Chen, Leitao; Schaefer, Laura

    2013-11-01

    Many of the numerical issues of LBM (lattice Boltzmann method) are not yet fully solved. One of the issues is its inability of handling complex geometric boundaries. Some published work, which is based on collision-streaming discretization of the LBE and corresponding lattice-like mesh, introduced successful treatments for curved boundaries. However, those schemes are not applicable to the boundaries with large curvature like porous media since the lattice-like mesh is not able to recognize it. In order to solve this issue, a 2D FVM (finite volume method)-based numerical framework is proposed, which completely uncouples the lattice structure and the spatial discretization and therefore brings the freedom of using any type of lattice structure while keeping the basic framework unchanged. The model is solved on an unstructured triangular mesh and triangular control volume. Boundary schemes of isothermal and thermal flow for the new numerical framework are also studied. Finally, a variety of isothermal and thermal flow problems are simulated and compared with other work. The proposed model can simulate the flow with a complex geometry to the desired accuracy in addition to complementing the simple geometry of the existing LB model.

  18. Resonant tunneling diode based on band gap engineered graphene antidot structures

    NASA Astrophysics Data System (ADS)

    Palla, Penchalaiah; Ethiraj, Anita S.; Raina, J. P.

    2016-04-01

    The present work demonstrates the operation and performance of double barrier Graphene Antidot Resonant Tunnel Diode (DBGA-RTD). Non-Equilibrium Green's Function (NEGF) frame work with tight-binding Hamiltonian and 2-D Poisson equations were solved self-consistently for device study. The interesting feature in this device is that it is an all graphene RTD with band gap engineered graphene antidot tunnel barriers. Another interesting new finding is that it shows negative differential resistance (NDR), which involves the resonant tunneling in the graphene quantum well through both the electron and hole bound states. The Graphene Antidot Lattice (GAL) barriers in this device efficiently improved the Peak to Valley Ratio to approximately 20 even at room temperature. A new fitting model is developed for the number of antidots and their corresponding effective barrier width, which will help in determining effective barrier width of any size of actual antidot geometry.

  19. Resonant tunneling diode based on band gap engineered graphene antidot structures

    SciTech Connect

    Palla, Penchalaiah Ethiraj, Anita S.; Raina, J. P.

    2016-04-13

    The present work demonstrates the operation and performance of double barrier Graphene Antidot Resonant Tunnel Diode (DBGA-RTD). Non-Equilibrium Green’s Function (NEGF) frame work with tight-binding Hamiltonian and 2-D Poisson equations were solved self-consistently for device study. The interesting feature in this device is that it is an all graphene RTD with band gap engineered graphene antidot tunnel barriers. Another interesting new finding is that it shows negative differential resistance (NDR), which involves the resonant tunneling in the graphene quantum well through both the electron and hole bound states. The Graphene Antidot Lattice (GAL) barriers in this device efficiently improved the Peak to Valley Ratio to approximately 20 even at room temperature. A new fitting model is developed for the number of antidots and their corresponding effective barrier width, which will help in determining effective barrier width of any size of actual antidot geometry.

  20. 2D lattice model of a lipid bilayer: Microscopic derivation and thermodynamic exploration.

    PubMed

    Hakobyan, Davit; Heuer, Andreas

    2017-02-14

    Based on all-atom Molecular Dynamics (MD) simulations of a lipid bilayer we present a systematic mapping on a 2D lattice model. Keeping the lipid type and the chain order parameter as key variables we derive a free energy functional, containing the enthalpic interaction of adjacent lipids as well as the tail entropy. The functional form of both functions is explicitly determined for saturated and polyunsaturated lipids. By studying the lattice model via Monte Carlo simulations it is possible to reproduce the temperature dependence of the distribution of order parameters of the pure lipids, including the prediction of the gel transition. Furthermore, application to a mixture of saturated and polyunsaturated lipids yields the correct phase separation behavior at lower temperatures with a simulation time reduced by approximately 7 orders of magnitude as compared to the corresponding MD simulations. Even the time-dependence of the de-mixing is reproduced on a semi-quantitative level. Due to the generality of the approach we envisage a large number of further applications, ranging from modeling larger sets of lipids, sterols, and solvent proteins to predicting nucleation barriers for the melting of lipids. Particularly, from the properties of the 2D lattice model one can directly read off the enthalpy and entropy change of the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine gel-to-liquid transition in excellent agreement with experimental and MD results.

  1. 2D lattice model of a lipid bilayer: Microscopic derivation and thermodynamic exploration

    NASA Astrophysics Data System (ADS)

    Hakobyan, Davit; Heuer, Andreas

    2017-02-01

    Based on all-atom Molecular Dynamics (MD) simulations of a lipid bilayer we present a systematic mapping on a 2D lattice model. Keeping the lipid type and the chain order parameter as key variables we derive a free energy functional, containing the enthalpic interaction of adjacent lipids as well as the tail entropy. The functional form of both functions is explicitly determined for saturated and polyunsaturated lipids. By studying the lattice model via Monte Carlo simulations it is possible to reproduce the temperature dependence of the distribution of order parameters of the pure lipids, including the prediction of the gel transition. Furthermore, application to a mixture of saturated and polyunsaturated lipids yields the correct phase separation behavior at lower temperatures with a simulation time reduced by approximately 7 orders of magnitude as compared to the corresponding MD simulations. Even the time-dependence of the de-mixing is reproduced on a semi-quantitative level. Due to the generality of the approach we envisage a large number of further applications, ranging from modeling larger sets of lipids, sterols, and solvent proteins to predicting nucleation barriers for the melting of lipids. Particularly, from the properties of the 2D lattice model one can directly read off the enthalpy and entropy change of the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine gel-to-liquid transition in excellent agreement with experimental and MD results.

  2. 2D photonic crystals on the Archimedean lattices (tribute to Johannes Kepler (1571 1630))

    NASA Astrophysics Data System (ADS)

    Gajić, R.; class="cross-out">D. Jovanović,

    2008-03-01

    Results of our research on 2D Archemedean lattice photonic crystals are presented. This involves the calculations of the band structures, band-gap maps, equifrequency contours and FDTD simulations of electromagnetic propagation through the structures as well as an experimental verification of negative refraction at microwaves. The band-gap dependence on dielectric contrast is established both for dielectric rods in air and air-holes in dielectric materials. A special emphasis is placed on possibilities of negative refraction and left-handedness in these structures. Together with the familiar Archimedean lattices like square, triangular, honeycomb and Kagome' ones, we consider also, the less known, (3 2, 4, 3, 4) (ladybug) and (3, 4, 6, 4) (honeycomb-ring) structures.

  3. Self-Assembly of Cubes into 2D Hexagonal and Honeycomb Lattices by Hexapolar Capillary Interactions

    NASA Astrophysics Data System (ADS)

    Soligno, Giuseppe; Dijkstra, Marjolein; van Roij, René

    2016-06-01

    Particles adsorbed at a fluid-fluid interface induce capillary deformations that determine their orientations and generate mutual capillary interactions which drive them to assemble into 2D ordered structures. We numerically calculate, by energy minimization, the capillary deformations induced by adsorbed cubes for various Young's contact angles. First, we show that capillarity is crucial not only for quantitative, but also for qualitative predictions of equilibrium configurations of a single cube. For a Young's contact angle close to 90°, we show that a single-adsorbed cube generates a hexapolar interface deformation with three rises and three depressions. Thanks to the threefold symmetry of this hexapole, strongly directional capillary interactions drive the cubes to self-assemble into hexagonal or graphenelike honeycomb lattices. By a simple free-energy model, we predict a density-temperature phase diagram in which both the honeycomb and hexagonal lattice phases are present as stable states.

  4. Novel Flux Matching Effects in Potentially Type-I Superconducting Au/Pb Bilayers Patterned with Antidot Lattices

    NASA Astrophysics Data System (ADS)

    de Long, Lance; Kryukov, Sergiy; Metlushko, Vitali

    2007-03-01

    We report AC and DC SQUID magnetometer data for Au(25nm)/Pb(x) bilayers (x = 50, 100 nm) patterned with square antidot (AD) lattices having AD diameter D = 600 nm and AD separation d = 1 micron, in DC magnetic fields applied perpendicular to the film plane. Both AC and DC data for x = 100 nm samples exhibit a ``two-horned'' magnetization m(H) well below TC, with small, sharp cusps having DC field spacings near 3 Oe. Just below TC = 6.2 K, m(H) is highly reversible, and exhibits at least two matching fields Hn = (20 Oe)n. This striking behavior is compared with recent theoretical models for flux matching in patterned films in the Type-I intermediate state, for which formation of ``giant vortices'' or pinning of normal domains by AD are possible. In contrast, data for x = 50 nm samples exhibit smooth (no small cusps) m(H) behavior with sharp matching peaks and highly irreversible behavior just below TC, typical of extensively studied, Type-II patterned films.

  5. Evidence for a Bose Glass Melting Line in a WGe Thin Film with a Square Antidot Lattice

    NASA Astrophysics Data System (ADS)

    de Long, L. E.; Lokhre, S.; Ye, T.; Metlushko, V. V.; Baert, M.; Rosseel, E.; van Bael, M. J.; Temst, K.; Moshchalkov, V. V.; Bruynseraede, Y.

    2001-03-01

    We present AC magnetization data for a W0.67Ge0.33 thin film patterned with a square lattice of antidots (AD) of diameter 350 nm and separation 1 µm. We infer a tentative, complex H-T phase boundary having sharp cusps at matching fields H[n] = n(21 Oe) similar to those predicted by Radzihovsky (PRL 74 (1995) 4923) at a transition between strongly pinned and weakly pinned Bose glass phases, and at the Bose-Mott transition predicted by Vinokur and Nelson (PRB 48 (1993) 13060), in the case of correlated pinning centers. Detailed AC frequency (0.05-800 Hz) and drive (0.05-2.5 Oe) dependences of the real and imaginary susceptibilities are presented as measures of nonequilibrium vortex response, in order to verify equilibrium phase transition behavior. Research at U. Kentucky and U.I.C. is supported by the U.S. DoE Office of Science, Div. Materials Sciences, Grant #DE-FG02-97ER45653, and at K. U. Leuven by the Flemish Fund for Scientific Research and the Concerted Action Program.

  6. Structure and Reversibility of 2D von Neumann Cellular Automata Over Triangular Lattice

    NASA Astrophysics Data System (ADS)

    Uguz, Selman; Redjepov, Shovkat; Acar, Ecem; Akin, Hasan

    2017-06-01

    Even though the fundamental main structure of cellular automata (CA) is a discrete special model, the global behaviors at many iterative times and on big scales could be a close, nearly a continuous, model system. CA theory is a very rich and useful phenomena of dynamical model that focuses on the local information being relayed to the neighboring cells to produce CA global behaviors. The mathematical points of the basic model imply the computable values of the mathematical structure of CA. After modeling the CA structure, an important problem is to be able to move forwards and backwards on CA to understand their behaviors in more elegant ways. A possible case is when CA is to be a reversible one. In this paper, we investigate the structure and the reversibility of two-dimensional (2D) finite, linear, triangular von Neumann CA with null boundary case. It is considered on ternary field ℤ3 (i.e. 3-state). We obtain their transition rule matrices for each special case. For given special triangular information (transition) rule matrices, we prove which triangular linear 2D von Neumann CAs are reversible or not. It is known that the reversibility cases of 2D CA are generally a much challenged problem. In the present study, the reversibility problem of 2D triangular, linear von Neumann CA with null boundary is resolved completely over ternary field. As far as we know, there is no structure and reversibility study of von Neumann 2D linear CA on triangular lattice in the literature. Due to the main CA structures being sufficiently simple to investigate in mathematical ways, and also very complex to obtain in chaotic systems, it is believed that the present construction can be applied to many areas related to these CA using any other transition rules.

  7. Analysis of the antiferromagnetic phase transitions of the 2D Kondo lattice

    NASA Astrophysics Data System (ADS)

    Jones, Barbara

    2010-03-01

    The Kondo lattice continues to present an interesting and relevant challenge, with its interactions between Kondo, RKKY, and coherent order. We present our study[1] of the antiferromagnetic quantum phase transitions of a 2D Kondo-Heisenberg square lattice. Starting from the nonlinear sigma model as a model of antiferromagnetism, we carry out a renormalization group analysis of the competing Kondo-RKKY interaction to one-loop order in an ɛ-expansion. We find a new quantum critical point (QCP) strongly affected by Kondo fluctuations. Near this QCP, there is a breakdown of hydrodynamic behavior, and the spin waves are logarithmically frozen out. The renormalization group results allow us to propose a new phase diagram near the antiferromagnetic fixed point of this 2D Kondo lattice model. The T=0 phase diagram contains four phases separated by a tetracritical point, the new QCP. For small spin fluctuations, we find a stable local magnetic moment antiferromagnet. For stronger coupling, region II is a metallic quantum disordered paramagnet. We find in region III a paramagnetic phase driven by Kondo interactions, with possible ground states of a heavy fermion liquid or a Kondo driven spin-liquid. The fourth phase is a spiral phase, or a large-Fermi-surface antiferromagnetic phase. We will describe these phases in more detail, including possible experimental confirmation of the spiral phase. The existence of the tetracritical point found here would be expected to affect the phase diagram at finite temperatures as well. In addition, It is hoped that these results, and particularly the Kondo interaction paramagnetic phase, will serve to bridge to solutions starting from the opposite limit, of a Kondo effect leading to a heavy fermion ground state. Work in collaboration with T. Tzen Ong. [4pt] [1] T. Ong and B. A. Jones, Phys. Rev. Lett. 103, 066405 (2009).

  8. Offline estimation of 2 D crystal lattice parameters by processing the electron diffraction image

    NASA Astrophysics Data System (ADS)

    Haq, Nuhman ul; Hayat, Khizar; Madani, Sajjad A.; Iqbal, Yaseen

    2012-03-01

    Electron diffraction provides useful information about the internal composition of materials and has been in the use of material scientists for more than fifty years. In order to extract useful information from offline diffraction images, they are manually analyzed by using some photometric technique. Manual analysis is however a cumbersome, laborious and difficult task. To reduce the labors of material scientists one can employ image processing techniques to perform automated analysis, due to the well established popularity and clear evidence of widely used image processing techniques. In this work an image processing technique is being proposed for the extraction of 2D unit cell information from diffraction images on one hand and finding the 2D point group contained by the lattices on the other. The technique employs a morphological shrinking operation to find the center of each spot in the underlying preprocessed diffraction image. This is followed by the extraction of eight points with reference to the spot produced by the transmitted electron beam. The resultant nine points, i.e. the extracted eight plus the reference spot generated by the transmitted electron beam, are then subjected to symmetry operations, rotation symmetry and mirror symmetry, in polar coordinate system, to classify the point group of the lattice produced by the electron diffraction. One of the difficult task, even in manual analysis, is to ascertain the exact spot where the transmitted electron beam hit the sample at the time of realization of the image. This has been accurately and intuitively done by employing the notion that the transmitted spot must have greater number of pixels, with the highest gray value, among the diffracted spots. The proposed strategy has been applied to a sample set of various images and the results shows that the technique is efficient in determining the unit cell in 2D and classify the point group with good accuracy.

  9. All optical active high decoder using integrated 2D square lattice photonic crystals

    NASA Astrophysics Data System (ADS)

    Moniem, Tamer A.

    2015-11-01

    The paper introduces a novel all optical active high 2 × 4 decoder based on 2D photonic crystals (PhC) of silicon rods with permittivity of ε = 10.1 × 10-11 farad/m. The main structure of optical decoder is designed using a combination of five nonlinear photonic crystal ring resonator, set of T-type waveguide, and line defect of Y and T branch splitters. The proposed structure has two logic input ports, four output ports, and one bias input port. The total size of the proposed 2 × 4 decoder is equal to 40 μm × 38 μm. The PhC structure has a square lattice of silicon rod with refractive index of 3.39 in air. The overall design and the results are discussed through the realization and the numerically simulation to confirm its operation and feasibility.

  10. A Refined Finite Element Formulation for the Microstructure-Dependent Analysis of Two-Dimensional (2D) Lattice Materials

    PubMed Central

    Mancusi, Geminiano; Feo, Luciano

    2012-01-01

    A finite element approximation is proposed for the dynamic analysis of two-dimensional (2D) lattice materials. The unit cell is modeled by means of a defined number of shear deformable micro-beams. The main innovative feature concerns the presence of a microstructure-dependent scale length, which allows the consideration of the so called size-effect that can be highly relevant, due to the characteristics of the lattice at the local scale. Some numerical results show the influence of the microstructure parameter on the dynamic behavior of two-dimensional lattice materials. PMID:28809291

  11. Enhancement of long-range correlations in a 2D vortex lattice by an incommensurate 1D disorder potential

    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.

  12. FDTD analysis of 2D triangular-lattice photonic crystals with arbitrary-shape inclusions based on unit cell transformation

    NASA Astrophysics Data System (ADS)

    Ma, Zetao; Ogusu, Kazuhiko

    2009-04-01

    A finite-difference time-domain method based on Yee's orthogonal cell is utilized to calculate the band structures of 2D triangular-lattice-based photonic crystals through a simple modification to properly shifting the boundaries of the original unit cell. A strategy is proposed for transforming the triangular unit cell into an orthogonal one, which can be used to calculate the band structures of 2D PhCs with various shapes of inclusions, such as triangular, quadrangular, and hexagonal shapes, to overcome the shortage of plane-wave expansion method for circular one. The band structures of 2D triangular-lattice-based PhCs with hexagonal air-holes are calculated and discussed for different values of its radius and rotation angle. The obtained results provide an insight to manipulate the band structures of PhCs.

  13. Micropolar dissipative models for the analysis of 2D dispersive waves in periodic lattices

    NASA Astrophysics Data System (ADS)

    Reda, H.; Ganghoffer, J. F.; Lakiss, H.

    2017-03-01

    The computation of the dispersion relations for dissipative periodic lattices having the attributes of metamaterials is an actual research topic raising the interest of researchers in the field of acoustics and wave propagation phenomena. We analyze in this contribution the impact of wave damping on the dispersion features of periodic lattices, which are modeled as beam-lattices. The band diagram structure and damping ratio are computed for different repetitive lattices, based on the homogenized continuum response of the initially discrete lattice architecture, modeled as Kelvin-Voigt viscoelastic beams. Three of these lattices (reentrant hexagonal, chiral diamond, hexachiral lattice) are auxetic metamaterials, since they show negative Poisson's ratio. The effective viscoelastic anisotropic continuum behavior of the lattices is first computed in terms of the homogenized stiffness and viscosity matrices, based on the discrete homogenization technique. The dynamical equations of motion are obtained for an equivalent homogenized micropolar continuum evaluated based on the homogenized properties, and the dispersion relation and damping ratio are obtained by inserting an harmonic plane waves Ansatz into these equations. The comparison of the acoustic properties obtained in the low frequency range for the four considered lattices shows that auxetic lattices attenuate waves at lower frequencies compared to the classical hexagonal lattice. The diamond chiral lattice shows the best attenuation properties of harmonic waves over the entire Brillouin zone, and the hexachiral lattice presents better acoustic properties than the reentrant hexagonal lattice. The range of validity of the effective continuum obtained by the discrete homogenization has been assessed by comparing the frequency band structure of this continuum with that obtained by a Floquet-Bloch analysis.

  14. Renormalization group flow and fixed point of the lattice topological charge in the 2D O(3) {sigma} model

    SciTech Connect

    DElia, M.; Farchioni, F.; Papa, A.

    1997-02-01

    We study the renormalization group evolution up to the fixed point of the lattice topological susceptibility in the 2D O(3) nonlinear {sigma} model. We start with a discretization of the continuum topological charge by a local charge density polynomial in the lattice fields. Among the different choices we propose also a Symanzik-improved lattice topological charge. We check step by step in the renormalization group iteration the progressive dumping of quantum fluctuations, which are responsible for the additive and multiplicative renormalizations of the lattice topological susceptibility with respect to the continuum definition. We find that already after three iterations these renormalizations are negligible and an excellent approximation of the fixed point is achieved. We also check by an explicit calculation that the assumption of slowly varying fields in iterating the renormalization group does not lead to a good approximation of the fixed point charge operator. {copyright} {ital 1997} {ital The American Physical Society}

  15. 2D surface optical lattice formed by plasmon polaritons with application to nanometer-scale molecular deposition.

    PubMed

    Yin, Yanning; Xu, Supeng; Li, Tao; Yin, Yaling; Xia, Yong; Yin, Jianping

    2017-08-10

    Surface plasmon polaritons, due to their tight spatial confinement and high local intensity, hold great promises in nanofabrication which is beyond the diffraction limit of conventional lithography. Here, we demonstrate theoretically the 2D surface optical lattices based on the surface plasmon polariton interference field, and the potential application to nanometer-scale molecular deposition. We present the different topologies of lattices generated by simple configurations on the substrate. By explicit theoretical derivations, we explain their formation and characteristics including field distribution, periodicity and phase dependence. We conclude that the topologies can not only possess a high stability, but also be dynamically manipulated via changing the polarization of the excitation laser. Nanometer-scale molecular deposition is simulated with these 2D lattices and discussed for improving the deposition resolution. The periodic lattice point with a width resolution of 33.2 nm can be obtained when the fullerene molecular beam is well-collimated. Our study can offer a superior alternative method to fabricate the spatially complicated 2D nanostructures, with the deposition array pitch serving as a reference standard for accurate and traceable metrology of the SI length standard.

  16. Signatures of Fermion Pairing with Unconventional Symmetry Around the BCS-BEC Crossover in a Quasi-2D Lattice

    NASA Astrophysics Data System (ADS)

    Volčko, Dušan; Quader, Khandker F.

    2012-12-01

    We consider fermions on a 2D square lattice with a finite-range pairing interaction, and obtain signatures for unconventional pair-symmetry states, dx2-y2 and extended-s (s*), in the Bardeen-Cooper-Schrieffer-Bose-Einstein Condensation crossover region. We find that the fermion momentum distribution function, vk2, the ratio of the Bogoliubov coefficients, vk/uk, and the Fourier transform of vk2 are strikingly different for d and s* symmetries in the crossover region. The chemical potential and the gap functions for both pairing symmetries show several interesting features as a function of interaction. Fermionic atoms in 2D optical lattices may provide a way to test these signatures. We discuss current generation cold atom experiments that may be utilized.

  17. On the sign problem in 2D lattice super Yang-Mills

    NASA Astrophysics Data System (ADS)

    Catterall, Simon; Galvez, Richard; Joseph, Anosh; Mehta, Dhagash

    2012-01-01

    In recent years a new class of supersymmetric lattice theories have been proposed which retain one or more exact supersymmetries for non-zero lattice spacing. Recently there has been some controversy in the literature concerning whether these theories suffer from a sign problem. In this paper we address this issue by conducting simulations of the mathcal{N} = (2, 2) and mathcal{N} = (8, 8) supersymmetric Yang-Mills theories in two dimensions for the U(N ) theories with N = 2, 3, 4, using the new twisted lattice formulations. Our results provide evidence that these theories do not suffer from a sign problem in the continuum limit. These results thus boost confidence that the new lattice formulations can be used successfully to explore non-perturbative aspects of four-dimensional mathcal{N} = 4 supersymmetric Yang-Mills theory.

  18. Hofstadter butterfly in the Falicov-Kimball model on some finite 2D lattices.

    PubMed

    Pradhan, Subhasree

    2016-12-21

    Spinless, interacting electrons on a finite size triangular lattice moving in an extremely strong perpendicular magnetic field are studied in comparison to a square lattice. Using a Falicov-Kimball model, the effects of Coulomb correlation, magnetic field and finite system size on their energy spectrum are observed. Exact diagonalization and Monte Carlo simulation methods (based on a modified Metropolis algorithm) have been employed to examine the recursive structure of the Hofstadter spectrum in the presence of several electronic correlation strengths for different system sizes. It is possible to introduce a gap in the density of states even in the absence of electron correlation, which is anticipated as a metal to insulator transition driven by an orbital magnetic field. With further inclusion of the interaction, the gap in the spectrum is modified and in some cases the correlation is found to suppress extra states manifested by the finite size effects. At a certain flux, the opened gap due to magnetic field is reduced by the Coulomb interaction. An orbital current is calculated for both the square and the triangular lattice with and without electron correlation. In the non-interacting limit, the bulk current shows several patterns, while the edge current shows oscillations with magnetic flux. The oscillations persist in the interacting limit for the square lattice, but not for the triangular lattice.

  19. Hofstadter butterfly in the Falicov-Kimball model on some finite 2D lattices

    NASA Astrophysics Data System (ADS)

    Pradhan, Subhasree

    2016-12-01

    Spinless, interacting electrons on a finite size triangular lattice moving in an extremely strong perpendicular magnetic field are studied in comparison to a square lattice. Using a Falicov-Kimball model, the effects of Coulomb correlation, magnetic field and finite system size on their energy spectrum are observed. Exact diagonalization and Monte Carlo simulation methods (based on a modified Metropolis algorithm) have been employed to examine the recursive structure of the Hofstadter spectrum in the presence of several electronic correlation strengths for different system sizes. It is possible to introduce a gap in the density of states even in the absence of electron correlation, which is anticipated as a metal to insulator transition driven by an orbital magnetic field. With further inclusion of the interaction, the gap in the spectrum is modified and in some cases the correlation is found to suppress extra states manifested by the finite size effects. At a certain flux, the opened gap due to magnetic field is reduced by the Coulomb interaction. An orbital current is calculated for both the square and the triangular lattice with and without electron correlation. In the non-interacting limit, the bulk current shows several patterns, while the edge current shows oscillations with magnetic flux. The oscillations persist in the interacting limit for the square lattice, but not for the triangular lattice.

  20. New optimization problems arising in modelling of 2D-crystal lattices

    NASA Astrophysics Data System (ADS)

    Evtushenko, Yury; Lurie, Sergey; Posypkin, Mikhail

    2016-10-01

    The paper considers the problem of finding the structure of a fragment of two-dimensional crystal lattice with the minimal energy. Atoms in a lattice reside on parallel lines (layers). The interatomic distances are the same within one layer but can differ for distinct layers. The energy of the piece of material is computed using so-called potential functions. We used Lennard-Jones, Morse and Tersoff potentials. The proposed formulation can serve as a scalable complex non-smooth optimization test. The paper evaluates various optimization techniques for the problem under consideration, compares their performances and draws the conclusion about the best choice of optimization methods for the problem under test. As a result we were able to locate minima meaningful from the physical point of view, e.g. reproducing graphene lattice.

  1. The puzzle of apparent linear lattice artifacts in the 2d non-linear σ-model and Symanzik's solution

    NASA Astrophysics Data System (ADS)

    Balog, Janos; Niedermayer, Ferenc; Weisz, Peter

    2010-01-01

    Lattice artifacts in the 2d O( n) non-linear σ-model are expected to be of the form O(a), and hence it was (when first observed) disturbing that some quantities in the O(3) model with various actions show parametrically stronger cutoff dependence, apparently O(a), up to very large correlation lengths. In a previous letter Balog et al. (2009) [1] we described the solution to this puzzle. Based on the conventional framework of Symanzik's effective action, we showed that there are logarithmic corrections to the O(a) artifacts which are especially large ( lna) for n=3 and that such artifacts are consistent with the data. In this paper we supply the technical details of this computation. Results of Monte Carlo simulations using various lattice actions for O(3) and O(4) are also presented.

  2. Interferometric Approach to Measuring Band Topology in 2D Optical Lattices

    NASA Astrophysics Data System (ADS)

    Abanin, Dmitry A.; Kitagawa, Takuya; Bloch, Immanuel; Demler, Eugene

    2013-04-01

    Recently, optical lattices with nonzero Berry’s phases of Bloch bands have been realized. New approaches for measuring Berry’s phases and topological properties of bands with experimental tools appropriate for ultracold atoms need to be developed. In this Letter, we propose an interferometric method for measuring Berry’s phases of two-dimensional Bloch bands. The key idea is to use a combination of Ramsey interference and Bloch oscillations to measure Zak phases, i.e., Berry’s phases for closed trajectories corresponding to reciprocal lattice vectors. We demonstrate that this technique can be used to measure the Berry curvature of Bloch bands, the π Berry’s phase of Dirac points, and the first Chern number of topological bands. We discuss several experimentally feasible realizations of this technique, which make it robust against low-frequency magnetic noise.

  3. Lattice Boltzmann methods for some 2-D nonlinear diffusion equations:Computational results

    SciTech Connect

    Elton, B.H.; Rodrigue, G.H. . Dept. of Applied Science Lawrence Livermore National Lab., CA ); Levermore, C.D. . Dept. of Mathematics)

    1990-01-01

    In this paper we examine two lattice Boltzmann methods (that are a derivative of lattice gas methods) for computing solutions to two two-dimensional nonlinear diffusion equations of the form {partial derivative}/{partial derivative}t u = v ({partial derivative}/{partial derivative}x D(u){partial derivative}/{partial derivative}x u + {partial derivative}/{partial derivative}y D(u){partial derivative}/{partial derivative}y u), where u = u({rvec x},t), {rvec x} {element of} R{sup 2}, v is a constant, and D(u) is a nonlinear term that arises from a Chapman-Enskog asymptotic expansion. In particular, we provide computational evidence supporting recent results showing that the methods are second order convergent (in the L{sub 1}-norm), conservative, conditionally monotone finite difference methods. Solutions computed via the lattice Boltzmann methods are compared with those computed by other explicit, second order, conservative, monotone finite difference methods. Results are reported for both the L{sub 1}- and L{sub {infinity}}-norms.

  4. [Antidote update].

    PubMed

    Kiyota, Kazuya

    2016-02-01

    In Japan, several products of the antidote for poisoning have been authorized in clinical use from some recent years. For example, Hydroxcobalamin for cyanide poisoning was introduced in 2008. In 2009, Ministry of Health, Labour and Welfare invited suggestions of demand of pharmaceutical products which is high in the need in the medical care but yet unauthorized. Japanese Society for Clinical Toxicology and Japan Poison Information Center applied some candidates including methyleneblue (MB) and fomepizole, both of them were authorized in clinical market in 2015. MB is the medicine for methemoglobinemia, caused by variety of chemical products such as nitrogen oxide. Fomepizole is the antidote for methanol and ethyleneglycol, blocking alcohol dehydrogenase.

  5. Equilibration Dynamics of Strongly Interacting Bosons in 2D Lattices with Disorder

    NASA Astrophysics Data System (ADS)

    Yan, Mi; Hui, Hoi-Yin; Rigol, Marcos; Scarola, V. W.

    2017-08-01

    Motivated by recent optical lattice experiments [J.-y. Choi et al., Science 352, 1547 (2016), 10.1126/science.aaf8834], we study the dynamics of strongly interacting bosons in the presence of disorder in two dimensions. We show that Gutzwiller mean-field theory (GMFT) captures the main experimental observations, which are a result of the competition between disorder and interactions. Our findings highlight the difficulty in distinguishing glassy dynamics, which can be captured by GMFT, and many-body localization, which cannot be captured by GMFT, and indicate the need for further experimental studies of this system.

  6. ``SAFFMAN-TAYLOR'' Finger in 2d Parallel Viscous: BGK Lattice Gas Simulations

    NASA Astrophysics Data System (ADS)

    Salin, Dominique; Rakotomalala, Nicole; Watzky, Philippe

    1996-11-01

    We study the displacement of miscible fluids between two parallel plates for different values of the Peclet number Pe and of the viscosity ratio M. The full Navier-Stokes problem is addressed. We use the BGK lattice gas method, which is well suited for miscible fluids and allows to introduce molecular diffusion at the microscopic scale of the lattice. This numerical experiment leads to a symmetric concentration profile about the middle of the gap between the plates. At Pe numbers of the order of 1, mixing involves diffusion and advection in the flow direction. At large Pe, the fluids do not mix and an interface between them can be defined. Moreover, above M ~ 10, the interface becomes a well defined finger, the reduced width of which tends to λ_∞=0.56 at large values of M. Assuming that miscible fluids at high Pe numbers are similar to immiscible fluids at high capillary numbers, we find the analytical shape of the finger, using an extrapolation of the Reinelt-Saffman calculations for a Stokes immiscible flow. Surprisingly, the result is that our finger can be deduced from the celebrated Saffman-Taylor' s one, obtained in a potential flow, by a streching in the flow direction by a numerical factor of 2.125.

  7. Hubbard Model study of Off Diagonally Confined fermions in a 2D Optical Lattice

    NASA Astrophysics Data System (ADS)

    Cone, Dave; Chiesa, Simone; Scalettar, Richard; Batrouni, George

    2010-03-01

    We report Quantum Monte Carlo simulations of a Hubbard Hamiltonian which incorporates a proposed new method for confining atoms in an optical lattice employing an inhomogeneous array of hopping matrix elements which trap atoms by going to zero at the lattice edges. This has been termed ``Off Diagonal Confinement (ODC)'' [1] to distinguish it from the more conventional use of a parabolic trap coupling to (diagonal) density operators. It has the advantage of producing systems which, while still being inhomogeneous, are entirely in the Mott phase, and allow simulations which are free of the sign problem at low temperatures. We analyze the effects of using ODC traps on the local density, density fluctuation, spin, and pairing correlation functions. Finally, we will discuss the advantages and importance of this new confinement technique for modeling correlated systems. Research supported by the Department of Energy, Office of Science SCIDAC program, DOE-DE-FC0206ER25793. [1] V.G. Rousseau et al., arXiv:0909.3543

  8. Modeling Selective Local Interactions with Memory: Motion on a 2D Lattice

    PubMed Central

    Weinberg, Daniel

    2014-01-01

    We consider a system of particles that simultaneously move on a two-dimensional periodic lattice at discrete times steps. Particles remember their last direction of movement and may either choose to continue moving in this direction, remain stationary, or move toward one of their neighbors. The form of motion is chosen based on predetermined stationary probabilities. Simulations of this model reveal a connection between these probabilities and the emerging patterns and size of aggregates. In addition, we develop a reaction diffusion master equation from which we derive a system of ODEs describing the dynamics of the particles on the lattice. Simulations demonstrate that solutions of the ODEs may replicate the aggregation patterns produced by the stochastic particle model. We investigate conditions on the parameters that influence the locations at which particles prefer to aggregate. This work is a two-dimensional generalization of [Galante & Levy, Physica D, http://dx.doi.org/10.1016/j.physd.2012.10.010], in which the corresponding one-dimensional problem was studied. PMID:25045193

  9. 2-D photonic crystals microcavity filters based on hexagonal lattice structures embedded in ridge waveguides

    NASA Astrophysics Data System (ADS)

    Jugessur, A. S.; Pottier, P.; De La Rue, R. M.; Kirk, A. G.

    2005-09-01

    Compact photonic crystal (PhC) microcavity filters in a ridge waveguide format could play a useful role for wavelength division multiplexing (WDM) and de-multiplexing functionality in dense integrated photonic circuits. The microcavity filters are embedded in ridge waveguides with high lateral refractive-index contrast because good lateral confinement and efficient coupling of light into the device can be achieved using this established waveguide technology. However, this configuration leads to significant modal mismatch at the interfaces between the PhC and waveguide sections, contributing to reflection losses and reduced transmission over much of the useful spectrum. By the same token, mode-matching features consisting of two rows of PhC holes with a different filling factor and displaced to mirror-image positions with respect to the outer two rows of the main PhC mirrors have been implemented to enhance the optical transmission by more than a factor of two. Furthermore, an increase in Q-factor (more than 100 %) is achieved by the addition of two further rows of PhC holes on either side of the microcavity. Moreover, Bragg-grating concepts have been applied in several other filter designs using the same hexagonal PhC lattice configuration, in an attempt to control the filter response. This work involves the design, fabrication (using electron-beam lithography and reactive ion etching) and characterization of such hexagonal-lattice PhC microcavity filters embedded in ridge waveguides.

  10. Modeling Selective Local Interactions with Memory: Motion on a 2D Lattice.

    PubMed

    Weinberg, Daniel; Levy, Doron

    2014-06-15

    We consider a system of particles that simultaneously move on a two-dimensional periodic lattice at discrete times steps. Particles remember their last direction of movement and may either choose to continue moving in this direction, remain stationary, or move toward one of their neighbors. The form of motion is chosen based on predetermined stationary probabilities. Simulations of this model reveal a connection between these probabilities and the emerging patterns and size of aggregates. In addition, we develop a reaction diffusion master equation from which we derive a system of ODEs describing the dynamics of the particles on the lattice. Simulations demonstrate that solutions of the ODEs may replicate the aggregation patterns produced by the stochastic particle model. We investigate conditions on the parameters that influence the locations at which particles prefer to aggregate. This work is a two-dimensional generalization of [Galante & Levy, Physica D, http://dx.doi.org/10.1016/j.physd.2012.10.010], in which the corresponding one-dimensional problem was studied.

  11. Kondo lattice on the edge of a 2D topological insulator

    NASA Astrophysics Data System (ADS)

    Maciejko, Joseph

    2012-02-01

    Much attention has been devoted recently to the experimental and theoretical study of the effect of magnetic impurities on the stability of the gapless boundary modes of topological insulators. When the quantum dynamics of the impurities is considered, those boundary modes constitute novel types of fermionic baths which may affect the nature of possible impurity phases and phase transitions. We study a regular one-dimensional array of quantum magnetic impurities interacting with the helical edge liquid of a two-dimensional time-reversal invariant topological insulator. Exact solutions at the special Toulouse and Luther-Emery points as well as a renormalization group analysis àla Anderson-Yuval allow us to construct a phase diagram in the space of Kondo coupling, electron-electron interaction strength, and electron density. We point out similarities and differences with the Kondo lattice in a ordinary one-dimensional electron gas.

  12. A hydrodynamically-consistent MRT lattice Boltzmann model on a 2D rectangular grid

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Min, Haoda; Guo, Zhaoli; Wang, Lian-Ping

    2016-12-01

    A multiple-relaxation time (MRT) lattice Boltzmann (LB) model on a D2Q9 rectangular grid is designed theoretically and validated numerically in the present work. By introducing stress components into the equilibrium moments, this MRT-LB model restores the isotropy of diffusive momentum transport at the macroscopic level (or in the continuum limit), leading to moment equations that are fully consistent with the Navier-Stokes equations. The model is derived by an inverse design process which is described in detail. Except one moment associated with the energy square, all other eight equilibrium moments can be theoretically and uniquely determined. The model is then carefully validated using both the two-dimensional decaying Taylor-Green vortex flow and lid-driven cavity flow, with different grid aspect ratios. The corresponding results from an earlier model (Bouzidi et al. (2001) [28]) are also presented for comparison. The results of Bouzidi et al.'s model show problems associated with anisotropy of viscosity coefficients, while the present model exhibits full isotropy and is accurate and stable.

  13. Adiabatic and Hamiltonian computing on a 2D lattice with simple two-qubit interactions

    NASA Astrophysics Data System (ADS)

    Lloyd, Seth; Terhal, Barbara M.

    2016-02-01

    We show how to perform universal Hamiltonian and adiabatic computing using a time-independent Hamiltonian on a 2D grid describing a system of hopping particles which string together and interact to perform the computation. In this construction, the movement of one particle is controlled by the presence or absence of other particles, an effective quantum field effect transistor that allows the construction of controlled-NOT and controlled-rotation gates. The construction translates into a model for universal quantum computation with time-independent two-qubit ZZ and XX+YY interactions on an (almost) planar grid. The effective Hamiltonian is arrived at by a single use of first-order perturbation theory avoiding the use of perturbation gadgets. The dynamics and spectral properties of the effective Hamiltonian can be fully determined as it corresponds to a particular realization of a mapping between a quantum circuit and a Hamiltonian called the space-time circuit-to-Hamiltonian construction. Because of the simple interactions required, and because no higher-order perturbation gadgets are employed, our construction is potentially realizable using superconducting or other solid-state qubits.

  14. Topologically induced swarming phase transition on a 2D percolated lattice

    NASA Astrophysics Data System (ADS)

    Quint, David A.; Gopinathan, Ajay

    2015-07-01

    The emergence of collective motion, or swarming, in groups of moving individuals who orient themselves using only information from their neighbors is a very general phenomenon that occurs at multiple spatio-temporal scales. Swarms that occur in natural environments typically have to contend with spatial disorder such as obstacles that can hinder an individual’s motion or can disrupt communication with neighbors. We study swarming agents, possessing both aligning and mutually avoiding repulsive interactions, in a 2D percolated network representing a topologically disordered environment. We numerically find a phase transition from a collectively moving swarm to a disordered gas-like state above a critical value of the topological or environmental disorder. For agents that utilize only alignment interactions, we find that the swarming transition does not exist in the large system size limit, while the addition of a mutually repulsive interaction can restore the existence of the transition at a finite critical value of disorder. We find there is a finite range of topological disorder where swarming can occur and that this range can be maximized by an optimal amount of mutual repulsion.

  15. A hierarchical lattice spring model to simulate the mechanics of 2-D materials-based composites

    NASA Astrophysics Data System (ADS)

    Brely, Lucas; Bosia, Federico; Pugno, Nicola

    2015-07-01

    In the field of engineering materials, strength and toughness are typically two mutually exclusive properties. Structural biological materials such as bone, tendon or dentin have resolved this conflict and show unprecedented damage tolerance, toughness and strength levels. The common feature of these materials is their hierarchical heterogeneous structure, which contributes to increased energy dissipation before failure occurring at different scale levels. These structural properties are the key to exceptional bioinspired material mechanical properties, in particular for nanocomposites. Here, we develop a numerical model in order to simulate the mechanisms involved in damage progression and energy dissipation at different size scales in nano- and macro-composites, which depend both on the heterogeneity of the material and on the type of hierarchical structure. Both these aspects have been incorporated into a 2-dimensional model based on a Lattice Spring Model, accounting for geometrical nonlinearities and including statistically-based fracture phenomena. The model has been validated by comparing numerical results to continuum and fracture mechanics results as well as finite elements simulations, and then employed to study how structural aspects impact on hierarchical composite material properties. Results obtained with the numerical code highlight the dependence of stress distributions on matrix properties and reinforcement dispersion, geometry and properties, and how failure of sacrificial elements is directly involved in the damage tolerance of the material. Thanks to the rapidly developing field of nanocomposite manufacture, it is already possible to artificially create materials with multi-scale hierarchical reinforcements. The developed code could be a valuable support in the design and optimization of these advanced materials, drawing inspiration and going beyond biological materials with exceptional mechanical properties.

  16. Engineering the electronic and magnetic properties of d(0) 2D dichalcogenide materials through vacancy doping and lattice strains.

    PubMed

    Ao, L; Pham, A; Xiao, H Y; Zu, X T; Li, S

    2016-03-14

    We have systematically investigated the effects of different vacancy defects in 2D d(0) materials SnS2 and ZrS2 using first principles calculations. The theoretical results show that the single cation vacancy and the vacancy complex like V-SnS6 can induce large magnetic moments (3-4 μB) in these single layer materials. Other defects, such as V-SnS3, V-S, V-ZrS3 and V-ZrS6, can result in n-type conductivity. In addition, the ab initio studies also reveal that the magnetic and conductive properties from the cation vacancy and the defect complex V-SnS6 can be modified using the compressive/tensile strain of the in-plane lattices. Specifically, the V-Zr doped ZrS2 monolayer can be tuned from a ferromagnetic semiconductor to a metallic/half-metallic material with decreasing/increasing magnetic moments depending on the external compressive/tensile strains. On the other hand, the semiconducting and magnetic properties of V-Sn doped SnS2 is preserved under different lattice compression and tension. For the defect complex like V-SnS6, only the lattice compression can tune the magnetic moments in SnS2. As a result, by manipulating the fabrication parameters, the magnetic and conductive properties of SnS2 and ZrS2 can be tuned without the need for chemical doping.

  17. A new class of aperiodic, long-range ordered artificial spin ices based upon Fibonacci distortions of 2D periodic lattices

    NASA Astrophysics Data System (ADS)

    Woods, Justin; Bhat, Vinayak; Farmer, Barry; Sklenar, Joseph; Teipel, Eric; Ketterson, John; Hastings, J. Todd; de Long, Lance

    2015-03-01

    Artificial spin ice (ASI) systems are composed of nanoscale ferromagnetic segments whose shape anisotropy dictates they behave as mesoscopic Ising spins. Most ASI have segments patterned on periodic lattices and a single vertex topology. We have continuously distorted 2D honeycomb and square lattices such that the pattern vertex spacings follow a Fibonacci chain sequence along primitive lattice directions. The Fibonacci distortion is related to the aperiodic translational symmetry of 2D artificial quasicrystals1 that cannot be viewed as continuous distortions of periodic lattices due to their forbidden (e.g., fivefold) rotational symmetries. In contrast, Fibonacci distortions of 2D periodic lattices can be ``turned on'' by control of the ratio of two lattice parameters d1 and d2. Distortions alter film segments such that pattern vertices are no longer equivalent and traditional spin ice rules are no longer strictly valid. We have performed OOMMF simulations of magnetization reversal for samples having different levels of distortion, and found the magnetic reversal to be dramatically slowed by small distortions (d1/d2 ~ 1). Research at Kentucky is supported by U.S. DoE Grant DE-FG02-97ER45653 and NSF Grant EPS-0814194.

  18. Impact of bounded noise on the formation and instability of spiral wave in a 2D Lattice of neurons

    NASA Astrophysics Data System (ADS)

    Yao, Yuangen; Deng, Haiyou; Yi, Ming; Ma, Jun

    2017-02-01

    Spiral waves in the neocortex may provide a spatial framework to organize cortical oscillations, thus help signal communication. However, noise influences spiral wave. Many previous theoretical studies about noise mainly focus on unbounded Gaussian noise, which contradicts that a real physical quantity is always bounded. Furthermore, non-Gaussian noise is also important for dynamical behaviors of excitable media. Nevertheless, there are no results concerning the effect of bounded noise on spiral wave till now. Based on Hodgkin-Huxley neuron model subjected to bounded noise with the form of Asin[ωt + σW(t)], the influences of bounded noise on the formation and instability of spiral wave in a two-dimensional (2D) square lattice of neurons are investigated in detail by separately adjusting the intensity σ, amplitude A, and frequency f of bounded noise. It is found that the increased intensity σ can facilitate the formation of spiral wave while the increased amplitude A tends to destroy spiral wave. Furthermore, frequency of bounded noise has the effect of facilitation or inhibition on pattern synchronization. Interestingly, for the appropriate intensity, amplitude and frequency can separately induce resonance-like phenomenon.

  19. Impact of bounded noise on the formation and instability of spiral wave in a 2D Lattice of neurons.

    PubMed

    Yao, Yuangen; Deng, Haiyou; Yi, Ming; Ma, Jun

    2017-02-21

    Spiral waves in the neocortex may provide a spatial framework to organize cortical oscillations, thus help signal communication. However, noise influences spiral wave. Many previous theoretical studies about noise mainly focus on unbounded Gaussian noise, which contradicts that a real physical quantity is always bounded. Furthermore, non-Gaussian noise is also important for dynamical behaviors of excitable media. Nevertheless, there are no results concerning the effect of bounded noise on spiral wave till now. Based on Hodgkin-Huxley neuron model subjected to bounded noise with the form of Asin[ωt + σW(t)], the influences of bounded noise on the formation and instability of spiral wave in a two-dimensional (2D) square lattice of neurons are investigated in detail by separately adjusting the intensity σ, amplitude A, and frequency f of bounded noise. It is found that the increased intensity σ can facilitate the formation of spiral wave while the increased amplitude A tends to destroy spiral wave. Furthermore, frequency of bounded noise has the effect of facilitation or inhibition on pattern synchronization. Interestingly, for the appropriate intensity, amplitude and frequency can separately induce resonance-like phenomenon.

  20. Impact of bounded noise on the formation and instability of spiral wave in a 2D Lattice of neurons

    PubMed Central

    Yao, Yuangen; Deng, Haiyou; Yi, Ming; Ma, Jun

    2017-01-01

    Spiral waves in the neocortex may provide a spatial framework to organize cortical oscillations, thus help signal communication. However, noise influences spiral wave. Many previous theoretical studies about noise mainly focus on unbounded Gaussian noise, which contradicts that a real physical quantity is always bounded. Furthermore, non-Gaussian noise is also important for dynamical behaviors of excitable media. Nevertheless, there are no results concerning the effect of bounded noise on spiral wave till now. Based on Hodgkin-Huxley neuron model subjected to bounded noise with the form of Asin[ωt + σW(t)], the influences of bounded noise on the formation and instability of spiral wave in a two-dimensional (2D) square lattice of neurons are investigated in detail by separately adjusting the intensity σ, amplitude A, and frequency f of bounded noise. It is found that the increased intensity σ can facilitate the formation of spiral wave while the increased amplitude A tends to destroy spiral wave. Furthermore, frequency of bounded noise has the effect of facilitation or inhibition on pattern synchronization. Interestingly, for the appropriate intensity, amplitude and frequency can separately induce resonance-like phenomenon. PMID:28220877

  1. Which cyanide antidote?

    PubMed

    Hall, Alan H; Saiers, Jane; Baud, Frédéric

    2009-01-01

    Cyanide has several antidotes, with differing mechanisms of action and diverse toxicological, clinical, and risk-benefit profiles. The international medical community lacks consensus about the antidote or antidotes with the best risk-benefit ratio. Critical assessment of cyanide antidotes is needed to aid in therapeutic and administrative decisions that will improve care for victims of cyanide poisoning (particularly poisoning from enclosed-space fire-smoke inhalation), and enhance readiness for cyanide toxic terrorism and other mass-casualty incidents. This paper reviews preclinical and clinical data on available cyanide antidotes and considers the profiles of these antidotes relative to properties of a hypothetical ideal cyanide antidote. Each of the antidotes shows evidence of efficacy in animal studies and clinical experience. The data available to date do not suggest obvious differences in efficacy among antidotes, with the exception of a slower onset of action of sodium thiosulfate (administered alone) than of the other antidotes. The potential for serious toxicity limits or prevents the use of the Cyanide Antidote Kit, dicobalt edetate, and 4-dimethylaminophenol in prehospital empiric treatment of suspected cyanide poisoning. Hydroxocobalamin differs from these antidotes in that it has not been associated with clinically significant toxicity in antidotal doses. Hydroxocobalamin is an antidote that seems to have many of the characteristics of the ideal cyanide antidote: rapid onset of action, neutralizes cyanide without interfering with cellular oxygen use, tolerability and safety profiles conducive to prehospital use, safe for use with smoke-inhalation victims, not harmful when administered to non-poisoned patients, easy to administer.

  2. Correlation and convolution filtering and image processing for pitch evaluation of 2D micro- and nano-scale gratings and lattices.

    PubMed

    Chen, Xiaomei; Koenders, Ludger; Parkinson, Simon

    2017-03-20

    We have mathematically explicated and experimentally demonstrated how a correlation and convolution filter can dramatically suppress the noise that coexists with the scanned topographic signals of two-dimensional (2D) gratings and lattices with 2D perspectives. To realize pitch evaluation, the true peaks' coordinates have been precisely acquired after detecting the local maxima from the filtered signal, followed by image processing. The combination of 2D filtering, local-maxima detecting, and image processing make up the pitch detection (PD) method. It is elucidated that the pitch average, uniformity, rotation angle, and orthogonal angle can be calculated using the PD method. This has been applied to the pitch evaluation of several 2D gratings and lattices, and the results are compared with the results of using the center-of-gravity (CG) and Fourier-transform-based (FT) method. The differences of pitch averages which are produced using the PD, CG, and FT methods are within 1.5 pixels. Moreover, the PD method has also been applied to detect the dense peaks of Si (111) 7×7 surface and the highly oriented pyrolytic graphite (HOPG) basal plane.

  3. Ratchet effect study in Si/SiGe heterostructures in the presence of asymmetrical antidots for different polarizations of microwaves

    NASA Astrophysics Data System (ADS)

    Bisotto, Isabelle; Kannan, Ethirajulu S.; Portal, Jean-Claude; Brown, Devin; Beck, Thomas J.; Krupko, Yuriy; Jalabert, Laurent; Fujita, Hiroyuki; Hoshi, Yusuke; Shiraki, Yasuhiro; Saraya, Takura

    2014-08-01

    In this work, we studied the photovoltage response of an antidot lattice to microwave radiation for different antidot parameters. The study was carried out in a Si/SiGe heterostructure by illuminating the antidot lattice with linearly polarized microwaves and recording the polarity of induced photovoltage for different angles of incidence. Our study revealed that with increased antidot density and etching depth, the polarity of induced photovoltage changed when the angle of incidence was rotated 90 degrees. In samples with large antidot density and/or a deeply etched antidot lattice, scattering was dominated by electron interaction with the asymmetrical potential created by semicircular antidots. The strong electron-electron interaction prevailed in other cases. Our study provides insight into the mechanism of interaction between microwaves and electrons in an antidot lattice, which is the key for developing an innovative ratchet-based device. Moreover, we present an original and fundamental example of antidot lattice etching through the use of a two-dimensional electron gas. This system deals with a hole lattice instead of an electron depletion in the antidot lattice region.

  4. Ratchet effect study in Si/SiGe heterostructures in the presence of asymmetrical antidots for different polarizations of microwaves.

    PubMed

    Bisotto, Isabelle; Kannan, Ethirajulu S; Portal, Jean-Claude; Brown, Devin; Beck, Thomas J; Krupko, Yuriy; Jalabert, Laurent; Fujita, Hiroyuki; Hoshi, Yusuke; Shiraki, Yasuhiro; Saraya, Takura

    2014-08-01

    In this work, we studied the photovoltage response of an antidot lattice to microwave radiation for different antidot parameters. The study was carried out in a Si/SiGe heterostructure by illuminating the antidot lattice with linearly polarized microwaves and recording the polarity of induced photovoltage for different angles of incidence. Our study revealed that with increased antidot density and etching depth, the polarity of induced photovoltage changed when the angle of incidence was rotated 90 degrees. In samples with large antidot density and/or a deeply etched antidot lattice, scattering was dominated by electron interaction with the asymmetrical potential created by semicircular antidots. The strong electron-electron interaction prevailed in other cases. Our study provides insight into the mechanism of interaction between microwaves and electrons in an antidot lattice, which is the key for developing an innovative ratchet-based device. Moreover, we present an original and fundamental example of antidot lattice etching through the use of a two-dimensional electron gas. This system deals with a hole lattice instead of an electron depletion in the antidot lattice region.

  5. 2D Lattice Boltzmann Simulation Of Chemical Reactions Within Rayleigh-Bénard And Poiseuille-Bénard Convection Systems

    NASA Astrophysics Data System (ADS)

    Amaya-Ventura, Gilberto; Rodríguez-Romo, Suemi

    2011-09-01

    This paper deals with the computational simulation of the reaction-diffusion-advection phenomena emerging in Rayleigh-Bénard (RB) and Poiseuille-Bénard reactive convection systems. We use the Boussinesq's approximation for buoyancy forces and the Lattice Boltzmann method (LBM). The first kinetic mesoscopic model proposed here is based on the discrete Boltzmann equation needed to solve the momentum balance coupled with buoyancy forces. Then, a second lattice Boltzmann algorithm is applied to solve the reaction-diffusion-advection equation to calculate the evolution of the chemical species concentration. We use a reactive system composed by nitrous oxide (so call laughing gas) in air as an example; its spatio-temporal decomposition is calculated. Two cases are considered, a rectangular enclosed cavity and an open channel. The simulations are performed at low Reynolds numbers and in a steady state between the first and second thermo-hydrodynamic instabilities. The results presented here, for the thermo-hydrodynamic behavior, are in good agreement with experimental data; while our| chemical kinetics simulation yields expected results. Some applications of our approach are related to chemical reactors and atmospheric phenomena, among others.

  6. [Antidotes in clinical toxicology].

    PubMed

    Hruby, K

    2013-09-01

    This overview describes antidotes, and their clinical pharmacology, that have an established significance in the currently practiced clinical toxicology because of their proven effectiveness in the treatment of serious poisonings. For the proper, efficient, and targeted use of an antidote, pharmacological knowledge is required, which is a central subject of this article. Current data from the literature are used as reference along with the accumulated experiences about possible adverse effects in order to include them in therapeutic considerations. The dosage of antidotes is the subject of several other review articles and is therefore not included in this synopsis.

  7. Negative refraction and flat-lens focusing in a 2D square-lattice photonic crystal at microwave and millimeter wave frequencies.

    PubMed

    Meisels, R; Gajic, R; Kuchar, F; Hingerl, K

    2006-07-24

    We report on a study of the wave propagation and refraction in a 2D square-lattice photonic crystal for the first two photonic bands as well as the coupling of the external waves and criteria for flat-lens focusing. Microwave experiments and numerical simulations are performed. Main results concern the transition from positive to negative refraction below the first band gap, the flat-lens focusing using a novel criterion, viz. the constancy of the ratio of the tangents of the incident and refracted angle. Focusing results for medium ( approximately 10) and ultra-large dielectric contrast ( approximately 100) are presented. In the latter case focusing with a spot size below one wavelength at distances several wavelengths behind the photonic crystal is achieved.

  8. Designing artificial two dimensional electron lattice on metal surface: a Kagome-like lattice as an example.

    PubMed

    Li, Shuai; Qiu, Wen-Xuan; Gao, Jin-Hua

    2016-07-07

    Recently, a new kind of artificial two dimensional (2D) electron lattice on the nanoscale, i.e. molecular graphene, has drawn a lot of interest, where the metal surface electrons are transformed into a honeycomb lattice via absorbing a molecular lattice on the metal surface [Gomes et al., Nature, 2012, 438, 306; Wang et al., Phys. Rev. Lett., 2014, 113, 196803]. In this work, we theoretically demonstrate that this technique can be readily used to build other complex 2D electron lattices on a metal surface, which are of high interest in the field of condensed matter physics. The main challenge to build a complex 2D electron lattice is that this is a quantum antidot system, where the absorbed molecule normally exerts a repulsive potential on the surface electrons. Thus, there is no straightforward corresponding relation between the molecular lattice pattern and the desired 2D lattice of surface electrons. Here, we give an interesting example about the Kagome lattice, which has exotic correlated electronic states. We design a special molecular pattern and show that this molecular lattice can transform the surface electrons into a Kagome-like lattice. The numerical simulation is conducted using a Cu(111) surface and CO molecules. We first estimate the effective parameters of the Cu/CO system by fitting experimental data of the molecular graphene. Then, we calculate the corresponding energy bands and LDOS of the surface electrons in the presence of the proposed molecular lattice. Finally, we interpret the numerical results by the tight binding model of the Kagome lattice. We hope that our work can stimulate further theoretical and experimental interest in this novel artificial 2D electron lattice system.

  9. Brillouin light scattering studies of 2D magnonic crystals

    NASA Astrophysics Data System (ADS)

    Tacchi, S.; Gubbiotti, G.; Madami, M.; Carlotti, G.

    2017-02-01

    Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.

  10. Brillouin light scattering studies of 2D magnonic crystals.

    PubMed

    Tacchi, S; Gubbiotti, G; Madami, M; Carlotti, G

    2017-02-22

    Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.

  11. Modifying toxicokinetics with antidotes.

    PubMed

    Baud, F J; Borron, S W; Bismuth, C

    1995-12-01

    Five approaches may be described through which antidotes can modify toxicokinetics: (1) Decreased bioavailability of the toxins; (2) Cellular redistribution of the toxin in the organism; (3) Promotion of elimination in an unchanged form; (4) Slowing of metabolic activation pathways; (5) Acceleration of metabolic deactivation pathways. However, the ability to modify toxicokinetics with a new treatment, while demonstrating an understanding of the mechanism of action, must never be construed to be, in and of itself, the goal of therapy. The ultimate evaluation of an antidote modifying toxicokinetics is strictly clinical.

  12. Band Gap Tuning of Armchair Graphene Nanoribbons by Using Antidotes

    NASA Astrophysics Data System (ADS)

    Zoghi, Milad; Goharrizi, Arash Yazdanpanah; Saremi, Mehdi

    2017-01-01

    The electronic properties of armchair graphene nanoribbons (AGNRs) can be changed by creating antidotes within the pristine ribbons and producing antidote super lattice AGNRs (ASL-AGNRs). In the present work, band gap tuning of ASL-AGNRs is investigated by varying the width of ribbons ( d W) and the distance between antidotes ( d L) for five different antidote topologies. Numerical tight-binding model is applied to obtain the band structure of the ribbons. Based on our results, it is found that the band gap of ASL-AGNRs can be increased or decreased in different cases. Furthermore, changing the width of ribbons generally results in more predictable␣band gap profiles compared to the variation of distance between antidotes. Consequently, by opting appropriate antidote topologies and dimensional parameters ( d W and d L), it is possible to gain a desired band gap size. This can be considered as an alternative solution in design of electronic and optoelectronic devices where tunable band gap values are needed.

  13. Dirac model of electronic transport in graphene antidot barriers.

    PubMed

    Thomsen, M R; Brun, S J; Pedersen, T G

    2014-08-20

    In order to use graphene for semiconductor applications, such as transistors with high on/off ratios, a band gap must be introduced into this otherwise semimetallic material. A promising method of achieving a band gap is by introducing nanoscale perforations (antidots) in a periodic pattern, known as a graphene antidot lattice (GAL). A graphene antidot barrier (GAB) can be made by introducing a 1D GAL strip in an otherwise pristine sheet of graphene. In this paper, we will use the Dirac equation (DE) with a spatially varying mass term to calculate the electronic transport through such structures. Our approach is much more general than previous attempts to use the Dirac equation to calculate scattering of Dirac electrons on antidots. The advantage of using the DE is that the computational time is scale invariant and our method may therefore be used to calculate properties of arbitrarily large structures. We show that the results of our Dirac model are in quantitative agreement with tight-binding for hexagonal antidots with armchair edges. Furthermore, for a wide range of structures, we verify that a relatively narrow GAB, with only a few antidots in the unit cell, is sufficient to give rise to a transport gap.

  14. The Antidote to Extremism

    ERIC Educational Resources Information Center

    Jackson, Anthony

    2016-01-01

    For centuries, education has been seen as an antidote to intolerance and conflict. In a world rocked by violence, much of it across cultural borders, developing students' cultural understanding has become more important than ever. In this article, Asia Society vice president Anthony Jackson discusses how two high schools in the Society's…

  15. The Antidote to Extremism

    ERIC Educational Resources Information Center

    Jackson, Anthony

    2016-01-01

    For centuries, education has been seen as an antidote to intolerance and conflict. In a world rocked by violence, much of it across cultural borders, developing students' cultural understanding has become more important than ever. In this article, Asia Society vice president Anthony Jackson discusses how two high schools in the Society's…

  16. HP-Lattice QSAR for dynein proteins: experimental proteomics (2D-electrophoresis, mass spectrometry) and theoretic study of a Leishmania infantum sequence.

    PubMed

    Dea-Ayuela, María Auxiliadora; Pérez-Castillo, Yunierkis; Meneses-Marcel, Alfredo; Ubeira, Florencio M; Bolas-Fernández, Francisco; Chou, Kuo-Chen; González-Díaz, Humberto

    2008-08-15

    The toxicity and inefficacy of actual organic drugs against Leishmaniosis justify research projects to find new molecular targets in Leishmania species including Leishmania infantum (L. infantum) and Leishmaniamajor (L. major), both important pathogens. In this sense, quantitative structure-activity relationship (QSAR) methods, which are very useful in Bioorganic and Medicinal Chemistry to discover small-sized drugs, may help to identify not only new drugs but also new drug targets, if we apply them to proteins. Dyneins are important proteins of these parasites governing fundamental processes such as cilia and flagella motion, nuclear migration, organization of the mitotic splinde, and chromosome separation during mitosis. However, despite the interest for them as potential drug targets, so far there has been no report whatsoever on dyneins with QSAR techniques. To the best of our knowledge, we report here the first QSAR for dynein proteins. We used as input the Spectral Moments of a Markov matrix associated to the HP-Lattice Network of the protein sequence. The data contain 411 protein sequences of different species selected by ClustalX to develop a QSAR that correctly discriminates on average between 92.75% and 92.51% of dyneins and other proteins in four different train and cross-validation datasets. We also report a combined experimental and theoretic study of a new dynein sequence in order to illustrate the utility of the model to search for potential drug targets with a practical example. First, we carried out a 2D-electrophoresis analysis of L. infantum biological samples. Next, we excised from 2D-E gels one spot of interest belonging to an unknown protein or protein fragment in the region M<20,200 and pI<4. We used MASCOT search engine to find proteins in the L. major data base with the highest similarity score to the MS of the protein isolated from L. infantum. We used the QSAR model to predict the new sequence as dynein with probability of 99.99% without

  17. Nano-spatial parameters from 3D to 2D lattice dimensionality by organic variant in [ZnCl4]- [R]+ hybrid materials: Structure, architecture-lattice dimensionality, microscopy, optical Eg and PL correlations

    NASA Astrophysics Data System (ADS)

    Kumar, Ajit; Verma, Sanjay K.; Alvi, P. A.; Jasrotia, Dinesh

    2016-04-01

    The nanospatial morphological features of [ZnCl]- [C5H4NCH3]+ hybrid derivative depicts 28 nm granular size and 3D spreader shape packing pattern as analyzed by FESEM and single crystal XRD structural studies. The organic moiety connect the inorganic components through N-H+…Cl- hydrogen bond to form a hybrid composite, the replacement of organic derivatives from 2-methylpyridine to 2-Amino-5-choloropyridine results the increase in granular size from 28nm to 60nm and unit cell packing pattern from 3D-2D lattice dimensionality along ac plane. The change in optical energy direct band gap value from 3.01eV for [ZnCl]- [C5H4NCH3]+ (HM1) to 3.42eV for [ZnCl]- [C5H5ClN2]+ (HM2) indicates the role of organic moiety in optical properties of hybrid materials. The photoluminescence emission spectra is observed in the wavelength range of 370 to 600 nm with maximum peak intensity of 9.66a.u. at 438 nm for (HM1) and 370 to 600 nm with max peak intensity of 9.91 a.u. at 442 nm for (HM2), indicating that the emission spectra lies in visible range. PL excitation spectra depicts the maximum excitation intensity [9.8] at 245.5 nm for (HM1) and its value of 9.9 a.u. at 294 nm, specify the excitation spectra lies in UV range. Photoluminescence excitation spectra is observed in the wavelength range of 280 to 350 nm with maximum peak intensity of 9.4 a.u. at 285.5 nm and 9.9 a.u. at 294 and 297 nm, indicating excitation in the UV spectrum. Single crystal growth process and detailed physiochemical characterization such as XRD, FESEM image analysis photoluminescence property reveals the structure stability with non-covalent interactions, lattice dimensionality (3D-2D) correlations interweaving into the design of inorganic-organic hybrid materials.

  18. Antidotes for acute cyanide poisoning.

    PubMed

    Borron, Stephen W; Baud, Frederic J

    2012-08-01

    Cyanide poisoning can present in multiple ways, given its widespread industrial use, presence in combustion products, multiple physical forms, and chemical structures. The primary target of toxicity is mitochondrial cytochrome oxidase. The onset and severity of poisoning depend on the route, dose, physicochemical structure and other variables. Common poisoning features include dyspnea, altered respiratory patterns, abnormal vital signs, altered mental status, seizures, and lactic acidosis. Our present knowledge supports cyanide poisoning treatment based on excellent supportive care with adjunctive antidotal therapy. Multiple antidotes exist and vary in regional availability. All currently marketed antidotes appear to be effective. Antidotal mechanisms include chelation, formation of stable, less toxic complexes, methemoglobin induction, and sulfane sulfur supplementation for detoxification by endogenous rhodanese. Each antidote has advantages and disadvantages. For example, hydroxocobalamin is safer than the methemoglobin inducers in patients with smoke inhalation. Research for new, safer and more effective cyanide antidotes continues.

  19. Antidotes for Cyanide Poisoning

    DTIC Science & Technology

    2013-01-01

    challenging position as professor ordinarius at the Depart- ment of Anaesthesiology . I pioneered from scratch in this position until 2009. My academic... experience in the Paris Fire Brigade. Clin Toxicol (Phila) 2006; 44 (Suppl 1):37 44. Antidotes for cyanide poisoning Kurt Anseeuwa*, Nicolas Delvaub...hydro- xocobalamin higher than 150 mg/kg. Given the theoretically synergistic action and given the experience in the treatment of the toxicity of

  20. [Theriac: medicine and antidote].

    PubMed

    Parojcic, Dusanka; Stupar, Dragan; Mirica, Milica

    2003-06-01

    Theriac was an ancient multi-ingredient preparation; originating as a cure for the bites of serpents, mad dogs and wild beasts, it later became an antidote to all known poisons. The name theriac (treacle), (Greek theriake, Latin theriaca, French thériaque) was derived from the Greek for wild beast - theriakos. The first formula was created by Mithridates Vl, King of Pontus, a skillful ruler but a monster of cruelty, who, living in such a fear of being poisoned, took a great interest in toxicology. In the 1st century AD, Nero's personal physician Andromachus improved the formula of Antidotum Mithridatium by adding flesh of vipers, which was commonly believed to be the best antidote against snakebite, and by increasing the proportion of opium. It became known as Theriac of Andromachus, and contained 64 ingredients including various minerals, herbals, poisons and animal flesh and blood, all combined with honey in the form of electuarium. Later it became the cure-all medicine which, accumulating all the simples into one form, was supposed to be a universal panacea against all diseases. In the Middle Ages this famous electuarium become a patent medicine and entered official dispensaries and pharmacopoeias. The most famous and expensive Theriac in Europe was that of Venice. It was not until the l8th century that it was excluded from medical use.

  1. Polymer antidotes for toxin sequestration.

    PubMed

    Weisman, Adam; Chou, Beverly; O'Brien, Jeffrey; Shea, Kenneth J

    2015-08-01

    Toxins delivered by envenomation, secreted by microorganisms, or unintentionally ingested can pose an immediate threat to life. Rapid intervention coupled with the appropriate antidote is required to mitigate the threat. Many antidotes are biological products and their cost, methods of production, potential for eliciting immunogenic responses, the time needed to generate them, and stability issues contribute to their limited availability and effectiveness. These factors exacerbate a world-wide challenge for providing treatment. In this review we evaluate a number of polymer constructs that may serve as alternative antidotes. The range of toxins investigated includes those from sources such as plants, animals and bacteria. The development of polymeric heavy metal sequestrants for use as antidotes to heavy metal poisoning faces similar challenges, thus recent findings in this area have also been included. Two general strategies have emerged for the development of polymeric antidotes. In one, the polymer acts as a scaffold for the presentation of ligands with a known affinity for the toxin. A second strategy is to generate polymers with an intrinsic affinity, and in some cases selectivity, to a range of toxins. Importantly, in vivo efficacy has been demonstrated for each of these strategies, which suggests that these approaches hold promise as an alternative to biological or small molecule based treatments.

  2. 46 CFR 154.1440 - Antidotes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Antidotes. 154.1440 Section 154.1440 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... Equipment § 154.1440 Antidotes. Each vessel must have the antidotes prescribed in the IMO Medical First...

  3. 46 CFR 153.930 - Cargo antidotes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo antidotes. 153.930 Section 153.930 Shipping COAST... Cargo antidotes. No person may operate a tankship that carries a cargo listed in Table 1 unless the tankship has on board the antidotes described for the cargo in the Medical First Aid Guide for Use...

  4. Observing Altshuler--Aronov--Spivak Oscillation in a Hexagonal Antidot Array of Monolayer Graphene

    NASA Astrophysics Data System (ADS)

    Yagi, Ryuta; Shimomura, Midori; Tahara, Fumiya; Kobara, Hiroaki; Fukada, Seiya

    2012-06-01

    We show that hexagonal antidot lattices of monolayer graphene exhibited the Altshuler--Aronov--Spivak (AAS) effect in low field magnetoresistance. In higher magnetic fields, Aharonov--Bohm-type oscillations were visible. The phase of AAS oscillation indicated that the chirality effect of graphene is suppressed because of inter-valley scattering due to boundary scatterings.

  5. Antidote: Civic Responsibility. Mississippi Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Mississippi state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  6. Antidote: Civic Responsibility. Illinois Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Illinois state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  7. Antidote: Civic Responsibility. Maine Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Maine state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student, or…

  8. Antidote: Civic Responsibility. California Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on California state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  9. Antidote: Civic Responsibility. Arkansas Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Arkansas state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  10. Antidote: Civic Responsibility. Connecticut Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Connecticut state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  11. Antidote: Civic Responsibility. Alaska Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Alaska state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  12. Antidote: Civic Responsibility. Arizona Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Arizona state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  13. Antidote: Civic Responsibility. Virginia Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Virginia state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  14. Antidote: Civic Responsibility. Oklahoma Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Oklahoma state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  15. Antidote: Civic Responsibility. Alabama Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Alabama state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  16. Antidote: Civic Responsibility. Utah Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Utah state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students. Developed to be presented by educators, law student, or…

  17. Antidote: Civic Responsibility. Missouri Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Missouri state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  18. Antidote: Civic Responsibility. Tennessee Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Tennessee state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  19. Antidote: Civic Responsibility. Iowa Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Iowa state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student, or…

  20. Antidote: Civic Responsibility. Georgia Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Georgia state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  1. Antidote: Civic Responsibility. Maryland Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Maryland state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  2. Antidote: Civic Responsibility. Kansas Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Kansas state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  3. Antidote: Civic Responsibility. Oregon Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Oregon state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  4. Antidote: Civic Responsibility. Minnesota Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Minnesota state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  5. Antidote: Civic Responsibility. Louisiana Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Louisiana state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  6. Antidote: Civic Responsibility. Nevada Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Nevada state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  7. Antidote: Civic Responsibility. Michigan Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Michigan state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  8. Antidote: Civic Responsibility. Texas Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Texas state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student, or…

  9. Antidote: Civic Responsibility. Washington Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Washington state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  10. Antidote: Civic Responsibility. Nebraska Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Nebraska state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  11. Antidote: Civic Responsibility. Indiana Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Indiana state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  12. Antidote: Civic Responsibility. Colorado Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Colorado state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  13. Antidote: Civic Responsibility. Hawaii Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Hawaii state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  14. Antidote: Civic Responsibility. Montana Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Montana state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  15. Antidote: Civic Responsibility. Pennsylvania Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Pennsylvania state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students. Developed to be presented by educators, law student,…

  16. Antidote: Civic Responsibility. Ohio Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Ohio state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student, or…

  17. Antidote: Civic Responsibility. Florida Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Florida state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  18. Antidote: Civic Responsibility. Massachusetts Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Massachusetts state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  19. Antidote: Civic Responsibility. Oregon Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Oregon state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  20. The dilemma of approving antidotes.

    PubMed

    Steffen, Christian

    2007-04-20

    Clinical trials with antidotes are difficult to perform for a variety of practical, ethical, and financial reasons. As acute poisoning is a rare event, the commercial interest in basic and clinical research is low. Poisoned patients are usually not available for normal clinical trial procedures and, if they are, they cannot give informed consent. This situation results in a dilemma: antidotes are essential drugs. A resolution of the Council of Europe requests to guarantee the optimal availability of antidotes and the improvement of their use. As comprehensive data on the efficacy of antidotes are often missing, a marketing authorisation under exceptional circumstances according to Article 14(8) of Regulation (EC) No. 276/2004, will often be the only way to get an approval, as: (1) the indications for which the product in question is intended are encountered so rarely that the applicant cannot reasonably be expected to provide comprehensive evidence ("orphan drug"), (2) in the present state of scientific knowledge, comprehensive information cannot be provided, or (3) it would be contrary to generally accepted principles of medical ethics to collect such data. Typically, data on antidotes are obtained from a patchwork of studies with animals, human tissue and a few observations from human poisoning corroborated with data from clinical observations and biochemistry. Generalisations from chemical and mechanistic similarities between groups of poisons are usual, but often lack scientific evidence. Current standards of good clinical practice can rarely be observed. Therefore, public funding and other financial support are necessary incentives to initiate trials in this important area.

  1. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.

    PubMed

    Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin

    2016-07-28

    In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs.

  2. Vesicant chemotherapy extravasation antidotes and treatments.

    PubMed

    Schulmeister, Lisa

    2009-08-01

    Oncology nurses and pharmacists often are given the responsibility of developing or updating institutional policies to manage vesicant chemotherapy extravasations. Antidote and treatment recommendations of vesicant chemotherapy manufacturers, antidotes and treatments approved by the U.S. Food and Drug Administration (FDA), and guidelines and recommendations made by professional oncology organizations are useful resources in this process. This article describes manufacturers' recommendations, lists antidotes and treatments approved by the FDA, and reviews published guidelines and recommendations. Available antidote and treatment formulations and their preparation and administration also are discussed.

  3. Novel, orally effective cyanide antidotes.

    PubMed

    Nagasawa, Herbert T; Goon, David J W; Crankshaw, Daune L; Vince, Robert; Patterson, Steven E

    2007-12-27

    A series of prodrugs of 3-mercaptopyruvate (3-MP), the substrate for the enzyme 3-mercaptopyruvate/cyanide sulfurtransferase (3-MPST) that converts cyanide to the nontoxic thiocyanate, which are highly effective cyanide antidotes, have been developed. These prodrugs of 3-MP are unique in being not only orally bioavailable, but may be administered up to an hour prior to cyanide as a prophylactic agent and are both rapid- or slow-acting when given parenterally.

  4. [Antidotal treatment of acebutolol poisoning].

    PubMed

    Strubelt, O

    1984-01-01

    In rats, the intravenous infusion with acebutolol lead to a dose dependent decrease of arterial blood pressure, heart rate, cardiac output and total peripheral resistance, to sinus bradycardia, widening of the QRS complex, 1st and 2nd degree AV-block and intraventricular conductance disturbances. Nine possible antidotes were administered i.v. to rats which had been infused with 2 mg/kg X min acebutolol for 60 min. Isoprenaline proved the best antidote against acebutolol antagonizing the bradycardia by 88% and the hypotension completely. The activities of orciprenaline and prenalterol were lower than those of isoprenaline. Dopamine, epinephrine and norepinephrine antagonized acebutolol-induced hypotension, but did not influence considerably the bradycardia. Glucagon, on the other hand, antagonized the acebutolol-induced bradycardia by 47% but exerted only a small activity on the hypotension. Aminophyllin and calcium were nearly ineffective as antidotes against acebutolol. Isoprenaline and dopamine infused simultaneously restored heart rate, arterial blood pressure and cardiac output of acebutol-poisoned rats. The survival time of rats infused with 4 mg/kg X min acebutolol was doubled by the additional infusion of 0.2 mg/kg X min isoprenaline. The antagonistic activity of a treatment with isoprenaline and dopamine against the cardiovascular toxicity of acebutolol was confirmed in rabbits.

  5. Effect of organic chain length on structure, electronic composition, lattice potential energy, and optical properties of 2D hybrid perovskites [(NH3)(CH2) n (NH3)]CuCl4, n = 2-9

    NASA Astrophysics Data System (ADS)

    Abdel-Aal, Seham K.; Kocher-Oberlehner, Gudrun; Ionov, Andrei; Mozhchil, R. N.

    2017-08-01

    Diammonium series of Cu hybrid perovskites of the formula [(NH3)(CH2) n (NH3)]CuCl4, n = 6-9 are prepared from an ethanolic solution in stoichiometric ratio 1:1 (organic/inorganic). Formation of the desired material was confirmed and characterizes by microchemical analysis, FTIR, XRD and XPS spectra. The structure consists of corner-shared octahedron [CuCl4]2- anion alternative by organic [(NH3)(CH2) n (NH3)]2+ cations. The organic and inorganic layers form infinite 2D sheet that are connected via NH···Cl hydrogen bond. The calculated lattice potential energy U pot (kJ/mol) and lattice enthalpy Δ H L (kJ/mol) are inversely proportional to the molecular volume V m (nm3) and organic chain length. Optical properties show strong absorption peak at UV-visible range. The band gap energy calculated using Kubelka-Munk equation shows the decrease of the energy gap as organic chain length increases. The introduction of bromide ion to [(NH3)(CH2) n (NH3)]CuCl2Br2 denoted 2C7CuCB hybrid has shifted the energy gap to lower values from 2.6 to 2.18 eV for 2C7CuCl (yellow) and 2C7CuCB (brown), respectively, at the same organic chain length. All elements of [(NH3)(CH2)9(NH3)]CuCl4 and [(NH3)(CH2)7(NH3)]CuCl2Br2 were found in XPS spectra, as well as valence band spectra.

  6. Geometrical complexity of the antidots unit cell effect on the spin wave excitations spectra

    NASA Astrophysics Data System (ADS)

    Zelent, M.; Tahir, N.; Gieniusz, R.; Kłos, J. W.; Wojciechowski, T.; Guzowska, U.; Maziewski, A.; Ding, J.; Adeyeye, A. O.; Krawczyk, M.

    2017-05-01

    Three types of antidot lattices (ADLs) based on a permalloy thin film, with increasing complexity of the unit cell: simple square, bi-component square, and wave-like ADLs were studied experimentally using both ferromagnetic resonance and Brillouin light scattering spectroscopy techniques. An additional small antidot placed in the center of the square unit cell induces significant modification of the ADL spin-wave spectrum and changes its dependence on the orientation of the in-plane applied magnetic field. The introduction of air-gaps connecting small and large antidots transforms the system into the wave-like ADL and results in further changes in the spin-wave spectrum, including a strong discrimination between two mutually orthogonal principal directions of the ADL in terms of spin-wave propagation. We also point out the impact of defected holes on the obtained spectra. The micromagnetic simulations and the calculation based on the plane wave method satisfactorily confirmed the experimental results.

  7. Antidotal treatment of cyanide poisoning.

    PubMed

    Mégarbane, Bruno; Delahaye, Arnaud; Goldgran-Tolédano, Dany; Baud, Frédéric J

    2003-04-01

    Cyanide poisoning may result from different exposures: residential fires, industrial accidents, drug and plant intoxication. Clinical features include coma, respiratory arrest and cardiovascular collapse. The biological hallmark is lactic acidosis. A plasma lactate concentration > or = 10 mmol/L in fire victims without severe burns and > or = 8 mmol/L in pure cyanide poisoned patients is a sensitive and specific indicator of cyanide intoxication. Many antidotes are available and efficient. However, therapeutic strategies are still debated. Our objective was to compare conventional treatments to hydroxocobalamin. This article reviews the literature on cyanide poisoning treatment. Conventional treatment of cyanide poisoning includes decontamination, supportive and specific treatment. Decontamination should be adapted to the route of poisoning and never postpone supportive treatment. Basic life support includes immediate administration of high flow of oxygen, airway protection and cardiopulmonary resuscitation. Advanced life support includes mechanical ventilation, catecholamine and sodium bicarbonate infusion. Supportive treatment is efficient but does not modify the time course or the body burden of cyanide. Numerous antidotes are available. Oxygen counteracts efficiently cyanide action at the mitochondrial level. Sodium thiosulfate, methemoglobin forming agents and cobalt compounds act efficiently by complexing or transforming cyanide into non-toxic stable derivatives. However, regarding the main clinical condition of cyanide poisoning, i.e. smoke inhalation, we should take into account not only the efficiency of antidotes but also their safety. Sodium thiosulfate is both efficient and safe, but acts with delay. Methemoglobin-forming agents are potent, but due to the transformation of hemoglobin into methemoglobin, they impair tissue delivery of oxygen. Experimental data showed increased mortality in carbon monoxide- and cyanide-poisoned rats treated with these

  8. Who gets antidotes? choosing the chosen few.

    PubMed

    Buckley, Nicholas A; Dawson, Andrew H; Juurlink, David N; Isbister, Geoffrey K

    2016-03-01

    An understanding of mechanisms, potential benefits and risks of antidotes is essential for clinicians who manage poisoned patients. Of the dozens of antidotes currently available, only a few are regularly used. These include activated charcoal, acetylcysteine, naloxone, sodium bicarbonate, atropine, flumazenil, therapeutic antibodies and various vitamins. Even then, most are used in a minority of poisonings. There is little randomized trial evidence to support the use of most antidotes. Consequently, decisions about when to use them are often based on a mechanistic understanding of the poisoning and the expected influence of the antidote on the patient's clinical course. For some antidotes, such as atropine and insulin, the doses employed can be orders of magnitude higher than standard dosing. Importantly, most poisoned patients who reach hospital can recover with supportive care alone. In low risk patients, the routine use of even low risk antidotes such as activated charcoal is unwarranted. In more serious poisonings, decisions regarding antidote use are generally guided by a risk/benefit assessment based on low quality evidence.

  9. [Antidote use in a pediatric emergency department].

    PubMed

    Martínez Sánchez, L; Almario Hernández, A F; Escuredo Argullós, L; Maçao, P; Trenchs Sainz de la Maza, V; Luaces Cubells, C

    2014-10-01

    Poisoning is an infrequent cause of consultation in a pediatric emergency department (PED), but it can be potentially serious. Pediatricians should know how to use the available antidotes properly. To analyze the use of antidotes in a PED and to assess the suitability of their indications. A retrospective review of antidote use in a PED between January 2008 and June 2012. Inclusion criteria were age younger than 18 years and consultation for suspicious poisoning by a substance that could be treated with an antidote. The adequacy of antidote indication was based on the recommendations of the Spanish Society of Pediatric Emergencies (SSPE). A total of 1728 consultations for suspicious poisoning (0.4% of the total visits in the PED) were recorded. In 353 cases (20.4%) the involved poison could be treated with an antidote. Sixty-seven patients received an antidote (3.9% of consultations for suspicious poisoning), and a total of 69 administrations of an antidote were made: 100% oxygen (46), N-acetylcysteine (10), flumazenil (4), naloxone (3), deferoxamine (2), vitamin K (2), bicarbonate (1), and carnitine (1). In 3 cases there was no indication for administration: flumazenil without respiratory depression, and vitamin K following coumarin exposure. As side effects, agitation was noted after the use of flumazenil, and a decrease in the prothrombin time during infusion of N-acetylcysteine. The administration of antidotes in this PED is uncommon and, mainly, in accordance with the SSPE recommendations, and without serious side effects. The use of flumazenil needs to be limited to the cases with a clear indication and without any contraindication. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  10. Antidote to Controversy? Responses to Carolyn Henly.

    ERIC Educational Resources Information Center

    Randall, Mary Ella; And Others

    1993-01-01

    Provides four practicing teachers' written responses to Carolyn Henly's article entitled "Reader Response Theory as Antidote to Controversy: Teaching "The Bluest Eye," which appears in the same issue. (HB)

  11. Humor. An antidote for terrorism.

    PubMed

    Pasquali, Elaine Anne

    2003-12-01

    It has been more than 2 years since the terrorist attacks of September 11, and the emotional fallout is still being felt. Nurses need to understand the crisis presented by terrorism and explore ways of dealing with it. The purpose of this article is to discuss humor as a means of facilitating coping with terrorism. Terrorism is a humanly caused disaster that threatens the physical, psychosocial, and spiritual aspects of one's personhood. The effects of humor strengthen these dimensions of self. In trying to deal with a terrorist event, people pass through several phases of emotional adjustment. Humor is a holistic, noninvasive strategy that may facilitate that adjustment and may be used effectively to heal both survivor-clients and disaster personnel who are working with them. Awareness of the phases of emotional adjustment, associated humor styles, and ways to incorporate therapeutic humor into crisis management approaches are essential for effectively using humor as an antidote for terrorism.

  12. Aharonov Bohm-type effects in different arrays of antidots

    NASA Astrophysics Data System (ADS)

    Kato, Masanori; Tanaka, Hiroyasu; Endo, Akira; Katsumoto, Shingo; Iye, Yasuhiro

    2006-08-01

    We have investigated Aharonov-Bohm-type oscillation in the quantum Hall plateau transition region in three types of square arrays of antidots; a large ( 50×160 antidots) array, a small ( 5×10 antidots) array, and the sample with antidots placed only near the side edges. The temperature dependence of the amplitude confirmed that the oscillation originates from the fine structure in the density of single particle states circumnavigating around each antidot. In addition, we have also observed Altshuler-Aronov-Spivak oscillation near zero magnetic field in square arrays of antidots.

  13. Antidotes for alcohol and glycol toxicity: translating mechanisms into treatments.

    PubMed

    McMartin, K E

    2010-09-01

    Translational toxicology can be defined as the movement of potential antidotes for the treatment of poisonings from basic mechanistic research to the marketplace. Because poisonings are infrequent, the clinical development of antidotes is fraught with trials and tribulations. Academic scientists often conduct basic mechanistic work with antidotes but are infrequently involved in further drug development. This article presents the development of 4-methylpyrazole (4MP) (fomepizole) as an antidote against toxic alcohol poisonings, particularly by methanol and ethylene glycol (EG).

  14. Manipulating electronic phase separation in strongly correlated oxides with an ordered array of antidots

    DOE PAGES

    Zhang, Kai; Du, Kai; Liu, Hao; ...

    2015-07-20

    The interesting transport and magnetic properties in manganites depend sensitively on the nucleation and growth of electronic phase-separated domains. In this paper, by fabricating antidot arrays in La0.325Pr0.3Ca0.375MnO3 (LPCMO) epitaxial thin films, we create ordered arrays of micrometer-sized ferromagnetic metallic (FMM) rings in the LPCMO films that lead to dramatically increased metal–insulator transition temperatures and reduced resistances. The FMM rings emerge from the edges of the antidots where the lattice symmetry is broken. Based on our Monte Carlo simulation, these FMM rings assist the nucleation and growth of FMM phase domains increasing the metal–insulator transition with decreasing temperature or increasingmore » magnetic field. Finally, this study points to a way in which electronic phase separation in manganites can be artificially controlled without changing chemical composition or applying external field.« less

  15. Manipulating electronic phase separation in strongly correlated oxides with an ordered array of antidots

    PubMed Central

    Zhang, Kai; Du, Kai; Liu, Hao; Zhang, X.-G.; Lan, Fanli; Lin, Hanxuan; Wei, Wengang; Zhu, Yinyan; Kou, Yunfang; Shao, Jian; Niu, Jiebin; Wang, Wenbin; Wu, Ruqian; Yin, Lifeng; Plummer, E. W.; Shen, Jian

    2015-01-01

    The interesting transport and magnetic properties in manganites depend sensitively on the nucleation and growth of electronic phase-separated domains. By fabricating antidot arrays in La0.325Pr0.3Ca0.375MnO3 (LPCMO) epitaxial thin films, we create ordered arrays of micrometer-sized ferromagnetic metallic (FMM) rings in the LPCMO films that lead to dramatically increased metal–insulator transition temperatures and reduced resistances. The FMM rings emerge from the edges of the antidots where the lattice symmetry is broken. Based on our Monte Carlo simulation, these FMM rings assist the nucleation and growth of FMM phase domains increasing the metal–insulator transition with decreasing temperature or increasing magnetic field. This study points to a way in which electronic phase separation in manganites can be artificially controlled without changing chemical composition or applying external field. PMID:26195791

  16. Self-assembled Metallic Dots and Antidots: Epitaxial Co on Ru(0001)

    NASA Astrophysics Data System (ADS)

    Yu, Chengtao; Li, Dongqi; Pearson, J.; Bader, S. D.

    2001-03-01

    We have grown 1-420 nm thick epitaxial Co wedge on Ru(0001) with molecular beam epitaxy at 350^oC to investigate self-assembly in metals utilizing ex-situ atomic force microscopy. A novel growth mode was observed whereby three-dimensional islands (dots) or a flat film network with deep holes (antidots) in truncated pyramidal shapes exist below or above 20 nm, respectively. The tops of the islands and the rims of the holes are flat with a root mean square roughness values of 0.3 nm. The lateral sizes of these dots/antidots, 10^2 nm, tend to be uniform. We postulate that this growth mode, similar to that of self-assembled quantum dots in semiconductors, is mainly driven by strain as a result of an 8% lateral mismatch between the basil plane lattice constants of bulk Co and Ru.

  17. Manipulating electronic phase separation in strongly correlated oxides with an ordered array of antidots

    SciTech Connect

    Zhang, Kai; Du, Kai; Liu, Hao; Zhang, X. -G.; Lan, Fanli; Lin, Hanxuan; Wei, Wengang; Zhu, Yinyan; Kou, Yunfang; Shao, Jian; Niu, Jiebin; Wang, Wenbin; Wu, Ruqian; Yin, Lifeng; Plummer, E. W.; Shen, Jian

    2015-07-20

    The interesting transport and magnetic properties in manganites depend sensitively on the nucleation and growth of electronic phase-separated domains. In this paper, by fabricating antidot arrays in La0.325Pr0.3Ca0.375MnO3 (LPCMO) epitaxial thin films, we create ordered arrays of micrometer-sized ferromagnetic metallic (FMM) rings in the LPCMO films that lead to dramatically increased metal–insulator transition temperatures and reduced resistances. The FMM rings emerge from the edges of the antidots where the lattice symmetry is broken. Based on our Monte Carlo simulation, these FMM rings assist the nucleation and growth of FMM phase domains increasing the metal–insulator transition with decreasing temperature or increasing magnetic field. Finally, this study points to a way in which electronic phase separation in manganites can be artificially controlled without changing chemical composition or applying external field.

  18. Antidote: Civic Responsibility. South Carolina Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on South Carolina state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  19. Antidote: Civic Responsibility. New Jersey Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on New Jersey state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  20. Antidote: Civic Responsibility. North Dakota Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on North Dakota state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  1. Antidote: Civic Responsibility. District of Columbia Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on District of Columbia state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators,…

  2. Antidote: Civic Responsibility. North Carolina Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on North Carolina state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  3. Antidote: Civic Responsibility. South Dakota Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on South Dakota state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  4. Antidote: Civic Responsibility. New York Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on New York state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law student,…

  5. Antidote: Civic Responsibility. Rhode Island Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Rhode Island state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  6. Antidote: Civic Responsibility. Puerto Rico Law.

    ERIC Educational Resources Information Center

    Phi Alpha Delta Law Fraternity International, Washington, DC.

    Designed for middle school through high school students, this unit contains eight lesson plans that focus on Puerto Rico state law. The state lessons correspond to lessons in the volume, "Antidote: Civic Responsibility. Drug Avoidance Lessons for Middle School & High School Students." Developed to be presented by educators, law…

  7. Development of antidotes for sodium monofluoroacetate (1080).

    PubMed

    Cook, C J; Eason, C T; Wickstrom, M; Devine, C D

    2001-01-01

    Baits containing sodium monofluoroacetate (1080) are commonly used in New Zealand during feral pest control operations. However, each year, a number of domestic dogs are unintentionally killed during these control operations, and a suitable antidote to 1080 intoxication is required. The primary toxic mechanism of 1080 is well known. However, as with other pathologies where energy deprivation is the main effect of intoxication, the cascade of effects that arises from this primary mechanism is complex. At present, putative antidotes for 1080 are generally unable to address the primary mechanism of intoxication but such agents may be able to control the cascade of secondary effects, which can result during intoxication. Part of the reason for this is that targeting the cascade can provide a longer window of time for antidote success. We have undertaken studies that identified some of the central nervous system (CNS) and systemic pathophysiological cascades caused by 1080 intoxication. Using this information we designed antidotes, on the basis of preventing different steps in this cascade. In the chicken model targeting systemic changes, in particular reducing effects of nitric oxide derivatives generated in cardiac muscle, proved successful in reducing fatality associated with 1080. In rats and sheep, targeting the CNS with a number of compounds including: glutamate; calcium and dopamine antagonists; gamma amino butyric acid agonists, and astressin-like compounds reduced fatalaties. However, to be successful in the rat and sheep model a given antidote needed to move quickly from systemic circulation across the blood brain barrier and into the CNS. The work also suggests ways in which specific biomarkers of 1080 exposure may be developed with respect to different species.

  8. 2D quasiperiodic plasmonic crystals

    PubMed Central

    Bauer, Christina; Kobiela, Georg; Giessen, Harald

    2012-01-01

    Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model. PMID:23209871

  9. 2D quasiperiodic plasmonic crystals.

    PubMed

    Bauer, Christina; Kobiela, Georg; Giessen, Harald

    2012-01-01

    Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model.

  10. Exact Solution of Ising Model in 2d Shortcut Network

    NASA Astrophysics Data System (ADS)

    Shanker, O.

    We give the exact solution to the Ising model in the shortcut network in the 2D limit. The solution is found by mapping the model to the square lattice model with Brascamp and Kunz boundary conditions.

  11. [Antidotes to novel direct oral anticoagulants].

    PubMed

    Khorev, N G; Momot, A P; Kon'kova, V O

    During the last 10 years, several novel direct oral anticoagulants (NOACs) have entered the clinical arena and were registered in the Russian Federation for use in patients presenting with atrial fibrillation, venous thrombosis, and pulmonary artery thromboembolism. NOACs are classified into two groups: direct thrombin inhibitor (notably dabigatran) and factor Xa inhibitors (including rivaroxaban, apixaban, and edoxaban). Their disadvantage is lack of specific antidotes in case of an emergency situation (injury, infarction, stroke requiring thrombolysis, urgent operation). The review contains the data on the existing therapeutic regimens of treating haemorrhage on the background of taking these coagulants. This is followed by analysing the present-day results of clinical trials aimed at working out pharmaceutical agents (andexanet alpha, idarucizumab, aripazine) being antidotes to direct thrombin inhibitor and the factor Xa inhibitors. Administration of these agents makes it possible to reverse coagulation and minimize the aftermaths of haemorrhage in patients taking these drugs, in emergency situations.

  12. [Antidotes--often expensive and not always available].

    PubMed

    Hoppu, Kalle; Pajarre-Sorsa, Suvi

    2012-01-01

    While there is seldom need for most anti-poisoning agents and antidotes, they should be quickly available, when needed. Local worst-case scenarios, regional staggering of the treatment, and distances must be taken into account at the health care unit level. Hospitals are fairly well equipped with the recommended antidotes. Replenishment of the stocks is complicated by continual disruptions in supply of antidotes. New antidotes in the updated recommendation include calcium folinate (leucovorin) for methanol poisoning and octreotide for the treatment of hypoglycemia caused by intoxications resulting from antidiabetics of the sulfonyl urea group.

  13. Spin waves in periodic antidot waveguide of complex base

    NASA Astrophysics Data System (ADS)

    Pan, Santanu; Kłos, Jarosław W.; Mieszczak, Szymon; Barman, Anjan; Krawczyk, Maciej

    2017-07-01

    We consider the planar magnonic waveguide with a periodic sequence of antidots forming a zig-zag pattern, where two neighboring antidots are shifted towards the opposite edges of the waveguide. This system has a complex base with two antidots in one unit cell. The Brillouin zone is here two-times narrower than the Brillouin zone for the waveguide without displacement of antidots. We have shown that for dispersion relation folded into a narrower Brillouin zone, a new frequency gap can be opened and their width can be controlled by the shift of the antidots. We found that the different strength of spin wave pinning at the edges of the periodic waveguide (and their antidots) determines the dependence of the width of gap on the shift of antidots. For the systems with completely free or ideally pinned magnetization, these dependencies are qualitatively different. We have found an optimum shift of antidot for maximizing the width of the gap for the system with pinned magnetization. More interestingly, we notice that for this kind of geometry of the structure, the majority of the modes are doubly degenerate at the edge of Brillouin zone and have a finite group velocity at the very close vicinity of the edge of Brillouin zone, for larger values of antidot shift. This empowers us to design a magnonic waveguide to steer the spin waves.

  14. Cobalt compounds as antidotes for hydrocyanic acid

    PubMed Central

    Evans, C. Lovatt

    1964-01-01

    The antidotal potency of a cobalt salt (acetate), of dicobalt edetate, of hydroxocobalamin and of cobinamide against hydrocyanic acid was examined mainly on mice and rabbits. All the compounds were active antidotes for up to twice the LD50; under some conditions for larger doses. The most successful was cobalt acetate for rabbits (5×LD50), which was effective at a molar cyanide/cobalt (CN/Co) ratio of 5, but had as a side-effect intense purgation. Hydroxocobalamin was irregular in action, but on the whole was most effective for mice (4.5×LD50 at a molar ratio of 1), and had no apparent side effects. Dicobalt edetate, at molar ratios of up to 2, was more effective for rabbits (3×LD50) than for mice (2×LD50), but had fewer side effects than cobalt acetate. The effect of thiosulphate was to augment the efficacy of dicobalt edetate and, in mice, that of hydroxocobalamin; but, apparently, in rabbits, to reduce that of hydroxocobalamin. Cobinamide, at a molar ratio of 1, was slightly more effective than hydroxocobalamin on rabbits and also less irregular in its action. Cobalt acetate by mouth was effective against orally administered hydrocyanic acid. The oxygen uptake of the body, reduced by cyanide, is rapidly reinstated when one of the cobalt antidotes has been successfully administered. PMID:14256807

  15. COBALT COMPOUNDS AS ANTIDOTES FOR HYDROCYANIC ACID.

    PubMed

    EVANS, C L

    1964-12-01

    The antidotal potency of a cobalt salt (acetate), of dicobalt edetate, of hydroxocobalamin and of cobinamide against hydrocyanic acid was examined mainly on mice and rabbits. All the compounds were active antidotes for up to twice the LD50; under some conditions for larger doses. The most successful was cobalt acetate for rabbits (5xLD50), which was effective at a molar cyanide/cobalt (CN/Co) ratio of 5, but had as a side-effect intense purgation. Hydroxocobalamin was irregular in action, but on the whole was most effective for mice (4.5xLD50 at a molar ratio of 1), and had no apparent side effects. Dicobalt edetate, at molar ratios of up to 2, was more effective for rabbits (3xLD50) than for mice (2xLD50), but had fewer side effects than cobalt acetate. The effect of thiosulphate was to augment the efficacy of dicobalt edetate and, in mice, that of hydroxocobalamin; but, apparently, in rabbits, to reduce that of hydroxocobalamin. Cobinamide, at a molar ratio of 1, was slightly more effective than hydroxocobalamin on rabbits and also less irregular in its action. Cobalt acetate by mouth was effective against orally administered hydrocyanic acid. The oxygen uptake of the body, reduced by cyanide, is rapidly reinstated when one of the cobalt antidotes has been successfully administered.

  16. Newer clinically available antithrombotics and their antidotes.

    PubMed

    Lévy, Samuel

    2014-09-01

    New oral anticoagulants (NOACs) have emerged as an alternative therapy to warfarin in the treatment of arterial and venous thromboembolism and in stroke prevention in patients with non-valvular atrial fibrillation (AF). Three of them, i.e., dabigatran, rivaroxaban, and apixaban, have been approved for clinical use in North America and in a number of European countries. In non-valvular AF, their approval was based on large randomized trials showing that they are non-inferior or even, in some instances, superior to warfarin. Dabigatran is a direct thrombin (factor IIa) inhibitor; rivaroxaban and apixaban are direct factor Xa inhibitors. Before using NOACs, it is recommended to become familiar with their pharmacological characteristics and their metabolism. The absence of specific antidotes is often cited as part of the possible weaknesses of NOACs. Antidotes are perceived to be useful in emergency situations such as life-threatening bleeding or non-elective major surgery. NOACs do not require blood monitoring, and therefore, patient compliance to the treatment is essential. For the present time, there are no specific antidotes available for the three NOACs approved for clinical use. However, phase I or phase II research studies in this area are ongoing. For dabigatran, a specific antidote has been tested in a rat model of anticoagulation, and a study in healthy male volunteers has been recently reported. For rivaroxaban, prothrombin complex concentrates (PCCs) have been found to completely reverse the prolongation of the prothrombin time induced by this NOAC. For apixaban, recombinant factor VII was found in an experimental study using human blood to be superior to activated PCC (aPCC) and PCC. More specific antidotes for rivaroxaban and apixaban are in phases I and II evaluation. The management of patients suffering from a major bleeding or requiring a non-elective major surgery includes non-specific reversal agents and is discussed in the light of a recent position

  17. Vertical 2D Heterostructures

    NASA Astrophysics Data System (ADS)

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  18. Common reversal agents/antidotes in small animal poisoning.

    PubMed

    Khan, Safdar A

    2012-03-01

    Different antidotes counteract the effect of a toxicant in several different ways. Antidotes can reverse, decrease, or prevent action of a toxicant. They can also help in achieving stabilization of vital signs, directly or indirectly, and promote excretion of a toxicant. However, overreliance on an antidote can be unrealistic and dangerous. While expectations of rapid recovery from antidotes are usually high, in a real life situation, there are many impediments in achieving this goal. The timing of its use, availability, cost, and sometimes adverse effects from the antidote itself can influence the results and outcome of a case. The majority of toxicants do not have a specific antidote therapy indicated and patients in these cases equally benefit from supportive care. In this chapter, commonly used antidotes and reversal agents in small animals are listed in a table form. The table lists generic name along with brand name of an antidote/reversal agent whenever available, main indications for their use, and provides comments or cautions in their use as needed. After stabilizing the patient and establishing the etiology, the clinicians must review more detailed management of that particular toxicant discussed here or in other references.

  19. Development of universal antidotes to control aptamer activity.

    PubMed

    Oney, Sabah; Lam, Ruby T S; Bompiani, Kristin M; Blake, Charlene M; Quick, George; Heidel, Jeremy D; Liu, Joanna Yi-Ching; Mack, Brendan C; Davis, Mark E; Leong, Kam W; Sullenger, Bruce A

    2009-10-01

    With an ever increasing number of people taking numerous medications, the need to safely administer drugs and limit unintended side effects has never been greater. Antidote control remains the most direct means to counteract acute side effects of drugs, but, unfortunately, it has been challenging and cost prohibitive to generate antidotes for most therapeutic agents. Here we describe the development of a set of antidote molecules that are capable of counteracting the effects of an entire class of therapeutic agents based upon aptamers. These universal antidotes exploit the fact that, when systemically administered, aptamers are the only free extracellular oligonucleotides found in circulation. We show that protein- and polymer-based molecules that capture oligonucleotides can reverse the activity of several aptamers in vitro and counteract aptamer activity in vivo. The availability of universal antidotes to control the activity of any aptamer suggests that aptamers may be a particularly safe class of therapeutics.

  20. Nano-antidotes for drug overdose and poisoning.

    PubMed

    Forster, Vincent; Leroux, Jean-Christophe

    2015-06-03

    The number of intoxications from xenobiotics--natural or synthetic foreign chemicals, or substances given in higher doses than typically present in humans--has risen tremendously in the last decade, placing poisoning as the leading external cause of death in the United States. This epidemic has fostered the development of antidotal nanomedicines, which we call "nano-antidotes," capable of efficiently neutralizing offending compounds in situ. Although prototype nano-antidotes have shown efficacy in proof-of-concept studies, the gap to clinical translation can only be filled if issues such as the clinical relevance of intoxication models and the safety profile of nano-antidotes are properly addressed. As the unmet medical needs in resuscitative care call for better treatments, this Perspective critically reviews the recent progress in antidotal medicine and emerging nanotechnologies.

  1. Antidote-mediated control of an anticoagulant aptamer in vivo.

    PubMed

    Rusconi, Christopher P; Roberts, Joseph D; Pitoc, George A; Nimjee, Shahid M; White, Rebekah R; Quick, George; Scardino, Elizabeth; Fay, William P; Sullenger, Bruce A

    2004-11-01

    Patient safety and treatment outcome could be improved if physicians could rapidly control the activity of therapeutic agents in their patients. Antidote control is the safest way to regulate drug activity, because unlike rapidly clearing drugs, control of the drug activity is independent of underlying patient physiology and co-morbidities. Until recently, however, there was no general method to discover antidote-controlled drugs. Here we demonstrate that the activity and side effects of a specific class of drugs, called aptamers, can be controlled by matched antidotes in vivo. The drug, an anticoagulant aptamer, systemically induces anticoagulation in pigs and inhibits thrombosis in murine models. The antidote rapidly reverses anticoagulation engendered by the drug, and prevents drug-induced bleeding in surgically challenged animals. These results demonstrate that rationally designed drug-antidote pairs can be generated to provide control over drug activities in animals.

  2. Anisotropy engineering using exchange bias on antidot templates

    NASA Astrophysics Data System (ADS)

    Goncalves, F. J. T.; Desautels, R. D.; Su, S.; Drysdale, T.; van Lierop, J.; Lin, K.-W.; Schmool, D. S.; Stamps, R. L.

    2015-06-01

    We explore an emerging device concept based on exchange bias used in conjunction with an antidot geometry to fine tune ferromagnetic resonances. Planar cavity ferromagnetic resonance is used to study the microwave response of NiO/NiFe bilayers with antidot structuring. A large frequency asymmetry with respect to an applied magnetic field is found across a broad field range whose underlying cause is linked to the distribution of magnetic poles at the antidot surfaces. This distribution is found to be particularly sensitive to the effects of exchange bias, and robust in regards to the quality of the antidot geometry. The template based antidot geometry we study offers advantages for practical device construction, and we show that it is suitable for broadband absorption and filtering applications, allowing tunable anisotropies via interface engineering.

  3. Development of universal antidotes to control aptamer activity

    PubMed Central

    Oney, Sabah; Lam, Ruby T S; Bompiani, Kristin M; Blake, Charlene M; Quick, George; Heidel, Jeremy D; Liu, Joanna Yi-Ching; Mack, Brendan C; Davis, Mark E; Leong, Kam W; Sullenger, Bruce A

    2010-01-01

    With an ever increasing number of people taking numerous medications, the need to safely administer drugs and limit unintended side effects has never been greater. Antidote control remains the most direct means to counteract acute side effects of drugs, but, unfortunately, it has been challenging and cost prohibitive to generate antidotes for most therapeutic agents. Here we describe the development of a set of antidote molecules that are capable of counteracting the effects of an entire class of therapeutic agents based upon aptamers. These universal antidotes exploit the fact that, when systemically administered, aptamers are the only free extracellular oligonucleotides found in circulation. We show that protein-and polymer-based molecules that capture oligonucleotides can reverse the activity of several aptamers in vitro and counteract aptamer activity in vivo. The availability of universal antidotes to control the activity of any aptamer suggests that aptamers may be a particularly safe class of therapeutics. PMID:19801990

  4. 2D semiconductor optoelectronics

    NASA Astrophysics Data System (ADS)

    Novoselov, Kostya

    The advent of graphene and related 2D materials has recently led to a new technology: heterostructures based on these atomically thin crystals. The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance, tunnelling transistors, photovoltaic devices, etc. By taking the complexity and functionality of such van der Waals heterostructures to the next level we introduce quantum wells engineered with one atomic plane precision. Light emission from such quantum wells, quantum dots and polaritonic effects will be discussed.

  5. Synthesis, structure, lattice energy and enthalpy of 2D hybrid perovskite [NH3(CH2)4NH3]CoCl4, compared to [NH3(CH2)nNH3]CoCl4, n=3-9

    NASA Astrophysics Data System (ADS)

    Abdel-Aal, Seham K.; Abdel-Rahman, Ahmed S.

    2017-01-01

    A new organic-inorganic 2D hybrid perovskite [NH3(CH2)4NH3]CoCl4,1,4butane diammonium tetra-chlorocobaltate, has been synthesized. Blue prismatic single crystals were grown from ethanolic solution in 1:1 stoichiometric ratio (organic/inorganic) by gradual cooling to room temperature after heating at 70 °C for 1 h. The hybrid crystallizes in a triclinic phase with the centrosymetric space group P 1 bar . Its unit cell parameters are a=7.2869 (2) Å, b=8.1506 (2) Å, c=10.4127 (3) Å, α=77.2950 (12)°, β=80.0588 (11)°, γ=82.8373 (12)° and Z=2. The final R factor is 0.064. The structure consists of organic dications [NH3(CH2)4NH3]2+ which act as spacer between layers of inorganic dianions [CoCl4]2- in which CoII ions are coordinated by four Cl atoms in an isolated tetrahedral structure. The organic and inorganic layers form infinite 2D sheets which are parallel to the ac plane, stacking alternatively along the b-axis, and are connected via N-H…. Cl hydrogen bonds. The lamellar structure of the 1,4 butane diammonium tetrachlorocobaltate hybrid is typically considered as naturally self-assembled multiple quantum wells (MQW). The calculated lattice potential energy Upot (kJ/mol) and lattice enthalpy ΔHL (kJ/mol) are inversely proportional to the molecular volume Vm (nm3) of perovskite hybrid of the formula [NH3(CH2)nNH3]CoCl4, n=3-9.

  6. Antidotal effectiveness of activated charcoal in rats

    SciTech Connect

    Curd-Sneed, C.D.

    1986-01-01

    This study was designed to investigate the relative adsorption of radiolabeled /sup 14/C-sodium pentobarbital by three types of activated charcoal. Factors affection adsorption of the drug by SuperChar, United States Pharmacopeia (USP), and Darco G-60 activated charcoals with surface areas of 2800-3500 m2/g, 1000 m/sup 2//g, and 650 m/sup 2//g, respectively, were studied both in vitro and in vivo. For in vitro experiments, the drug was dissolved in water of 70% sorbitol (w/v), and the maximum binding capacity and dissociation constants for each of the charcoals were calculated. Rank order of maximum binding capacity was directly proportional to charcoal surface area in both water and sorbitol, while the dissociation constants for the charcoals in water were not different. For in vivo experiments, absorption of orally administered sodium pentobarbital (40 mg/kg) was studied in rats with and without activated charcoal administration. The results of this research suggest that: (1) SuperChar given in water possesses the greatest antidotal efficacy, (2) sorbitol induced catharsis does not reduce oral absorption of sodium pentobarbital, and (3) sorbitol enhances the antidotal efficacy of USP charcoal.

  7. Toxicology: pearls and pitfalls in the use of antidotes.

    PubMed

    Smollin, Craig G

    2010-02-01

    Although most poisonings require only supportive care, the emergency physician must recognize when the use of an antidote is required, and understand the risks and benefits of the treatment rendered. Although the more commonly instituted specific therapy in acute poisoning is the administration of intravenous fluids followed by the administration of oxygen, in certain circumstances prompt administration of a specific antidote may be required, and failure to identify these circumstances may lead to significant morbidity or mortality. This article describes select antidotes, and discusses their indications and potential pitfalls.

  8. Interaction of nerve agent antidotes with cholinergic systems.

    PubMed

    Soukup, O; Tobin, G; Kumar, U K; Binder, J; Proska, J; Jun, D; Fusek, J; Kuca, K

    2010-01-01

    The poisoning with organophosphorus compounds represents a life threatening danger especially in the time of terroristic menace. No universal antidote has been developed yet and other therapeutic approaches not related to reactivation of acetylcholinesterase are being investigated. This review describes the main features of the cholinergic system, cholinergic receptors, cholinesterases and their inhibitors. It also focuses on the organophosphorus nerve agents, their properties, effects and a large part describes various possibilities in treatments, mainly traditional oxime therapies based on reactivation of AChE. Furthermore, non-cholinesterase coupled antidotal effects of the oximes are thoroughly discussed. These antidotal effects principally include oxime interactions with muscarinic and nicotinic receptors.

  9. Spin relaxations in 2D electron gas determined by the memory in the carrier dynamics.

    NASA Astrophysics Data System (ADS)

    Sherman, Eugene; Glazov, Mikhail

    2007-03-01

    The effects of long memory, in carrier dynamics in a magnetic field, on spin polarization evolution in 2D electron gas are investigated qualitatively and quantitatively. As examples we consider (i) systems with random Rashba-type SO coupling and (ii) quantum wells with rigid short-range scatterers (antidotes) and regular Dresselhaus SO coupling. In both cases the spin dynamics is strongly non-Markovian. In the system with the random SO coupling the time dependence of the spin polarization shows Gaussian rather than exponential behavior with the cusps corresponding to the electron revolutions. The relaxation speeds up with the increase of the magnetic field. In the system with antidotes scattering, the spin polarization shows a long-tail behavior with the relaxation rate determined by inelastic electron-phonon and electron-electron collisions and demonstrates unusual field dependence.

  10. Subwavelength lattice optics by evolutionary design.

    PubMed

    Huntington, Mark D; Lauhon, Lincoln J; Odom, Teri W

    2014-12-10

    This paper describes a new class of structured optical materials--lattice opto-materials--that can manipulate the flow of visible light into a wide range of three-dimensional profiles using evolutionary design principles. Lattice opto-materials are based on the discretization of a surface into a two-dimensional (2D) subwavelength lattice whose individual lattice sites can be controlled to achieve a programmed optical response. To access a desired optical property, we designed a lattice evolutionary algorithm that includes and optimizes contributions from every element in the lattice. Lattice opto-materials can exhibit simple properties, such as on- and off-axis focusing, and can also concentrate light into multiple, discrete spots. We expanded the unit cell shapes of the lattice to achieve distinct, polarization-dependent optical responses from the same 2D patterned substrate. Finally, these lattice opto-materials can also be combined into architectures that resemble a new type of compound flat lens.

  11. A specific antidote for dabigatran: functional and structural characterization.

    PubMed

    Schiele, Felix; van Ryn, Joanne; Canada, Keith; Newsome, Corey; Sepulveda, Eliud; Park, John; Nar, Herbert; Litzenburger, Tobias

    2013-05-02

    Dabigatran etexilate is a direct thrombin inhibitor and used widely as an anticoagulant for the prevention of stroke in patients with atrial fibrillation. However, anticoagulation therapy can be associated with an increased risk of bleeding. Here, we present data on the identification, humanization, and in vitro pharmacology of an antidote for dabigatran (aDabi-Fab). The X-ray crystal structure of dabigatran in complex with the antidote reveals many structural similarities of dabigatran recognition compared with thrombin. By a tighter network of interactions, the antidote achieves an affinity for dabigatran that is ~350 times stronger than its affinity for thrombin. Despite the structural similarities in the mode of dabigatran binding, the antidote does not bind known thrombin substrates and has no activity in coagulation tests or platelet aggregation. In addition we demonstrate that the antidote rapidly reversed the anticoagulant activity of dabigatran in vivo in a rat model of anticoagulation. This is the first report of a specific antidote for a next-generation anticoagulant that may become a valuable tool in patients who require emergency procedures.

  12. Expert Consensus Guidelines for Stocking of Antidotes in Hospitals That Provide Emergency Care.

    PubMed

    Dart, Richard C; Goldfrank, Lewis R; Erstad, Brian L; Huang, David T; Todd, Knox H; Weitz, Jeffrey; Bebarta, Vikhyat S; Caravati, E Martin; Henretig, Fred M; Delbridge, Theodore R; Banner, William; Schneider, Sandra M; Anderson, Victoria E

    2017-06-29

    We provide recommendations for stocking of antidotes used in emergency departments (EDs). An expert panel representing diverse perspectives (clinical pharmacology, medical toxicology, critical care medicine, hematology/oncology, hospital pharmacy, emergency medicine, emergency medical services, pediatric emergency medicine, pediatric critical care medicine, poison centers, hospital administration, and public health) was formed to create recommendations for antidote stocking. Using a standardized summary of the medical literature, the primary reviewer for each antidote proposed guidelines for antidote stocking to the full panel. The panel used a formal iterative process to reach their recommendation for both the quantity of antidote that should be stocked and the acceptable timeframe for its delivery. The panel recommended consideration of 45 antidotes; 44 were recommended for stocking, of which 23 should be immediately available. In most hospitals, this timeframe requires that the antidote be stocked in a location that allows immediate availability. Another 14 antidotes were recommended for availability within 1 hour of the decision to administer, allowing the antidote to be stocked in the hospital pharmacy if the hospital has a mechanism for prompt delivery of antidotes. The panel recommended that each hospital perform a formal antidote hazard vulnerability assessment to determine its specific need for antidote stocking. Antidote administration is an important part of emergency care. These expert recommendations provide a tool for hospitals that offer emergency care to provide appropriate care of poisoned patients. Copyright © 2017 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  13. Broad-Band FMR of Patterned Square Arrays of Square Permalloy Antidots

    NASA Astrophysics Data System (ADS)

    Bhat, Vinayak; Sklenar, Joseph; Ketterson, John; Delong, Lance

    2011-03-01

    We have used electron beam lithography to pattern 25-nm-thick Permalloy films with square arrays of square antidots of size D = 300, 400, 500 and 700 nm and same lattice constant d = 1000 nm, using a lift-off technique. Broadband FMR was used to observe localized modes , showing four-fold rotational symmetry for in-plane DC magnetic field. We have studied FMR spectra spanning the ferromagnetic hysteresis regime around 250 MHz, up to the saturation regime ending near 14 GHz, and observe the appearance and disappearance of various FMR modes, especially at frequencies below 7 GHz. We have observed history-dependent modes below 3 GHz that may be associated with domain walls. UK research supported by U.S. DoE Grant No. DE-FG02-97ER45653.

  14. 48 CFR 225.7005 - Restriction on certain chemical weapons antidote.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Restriction on certain chemical weapons antidote. 225.7005 Section 225.7005 Federal Acquisition Regulations System DEFENSE... on certain chemical weapons antidote. ...

  15. 48 CFR 225.7005 - Restriction on certain chemical weapons antidote.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Restriction on certain chemical weapons antidote. 225.7005 Section 225.7005 Federal Acquisition Regulations System DEFENSE... on certain chemical weapons antidote. ...

  16. 48 CFR 225.7005 - Restriction on certain chemical weapons antidote.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Restriction on certain chemical weapons antidote. 225.7005 Section 225.7005 Federal Acquisition Regulations System DEFENSE... on certain chemical weapons antidote. ...

  17. 48 CFR 225.7005 - Restriction on certain chemical weapons antidote.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Restriction on certain chemical weapons antidote. 225.7005 Section 225.7005 Federal Acquisition Regulations System DEFENSE... on certain chemical weapons antidote. ...

  18. 48 CFR 225.7005 - Restriction on certain chemical weapons antidote.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Restriction on certain chemical weapons antidote. 225.7005 Section 225.7005 Federal Acquisition Regulations System DEFENSE... on certain chemical weapons antidote....

  19. Construction of 2D lateral pseudoheterostructures by strain engineering

    NASA Astrophysics Data System (ADS)

    Feng, Haifeng; Zhuang, Jincheng; Slattery, Ashley D.; Wang, Liang; Xu, Zhongfei; Xu, Xun; Mitchell, David; Zheng, Tian; Li, Songlin; Higgins, Michael; Ren, Long; Sun, Ziqi; Xue Dou, Shi; Du, Yi; Hao, Weichang

    2017-06-01

    Two-dimensional (2D) lateral heterostructures host unconventional physical properties due to their controllable band-offset tuning and interfacial sensitive characteristic. The lattice mismatch results in the difficulties to construct the perfect atomic interface in such 2D lateral heterostructures, which in turn limits their desirable properties and performances in applications. In this work, strain-modulated 2D lateral pseudoheterogeneous structures are designed and realized in the single-component 2D BiOBr nanosheets by taking advantage of their strain-sensitive crystal and electronic structures. The pseudoheterogeneous interface without atomic mismatch can be feasibly modulated by local strain distribution, which exhibits similar local electronic band structure of corresponding heterostructures. Significant enhancement in charge separation at the pseudoheterostructure was demonstrated under visible light irradiation, which is given rise to the controllable electronic band alignment across the interface. The construction of the lateral pseudoheterostructure offers a feasible and promising way to build unprecedented 2D systems with exciting properties.

  20. Delineating the role of ripples on the thermal expansion of 2D honeycomb materials: graphene, 2D h-BN and monolayer (ML)-MoS2.

    PubMed

    Anees, P; Valsakumar, M C; Panigrahi, B K

    2017-04-19

    We delineated the role of thermally excited ripples on the thermal expansion properties of 2D honeycomb materials (free-standing graphene, 2D h-BN, and ML-MoS2), by explicitly carrying out three-dimensional (3D) and two-dimensional (2D) molecular dynamics simulations. In 3D simulations, the in-plane lattice parameter (a-lattice) of graphene and 2D h-BN shows thermal contraction over a wide range of temperatures and exhibits a strong system size dependence. The 2D simulations of the very same system show a reverse trend, where the a-lattice expands in the whole computed temperature range. In contrast to graphene and 2D h-BN, the a-lattice of ML-MoS2 shows thermal expansion in both 2D and 3D simulations and their system size dependence is marginal. By analyzing the phonon dispersion at 300 K, we found that the discrepancy between 2D and 3D simulations of graphene and 2D h-BN is due to the absence of out-of-plane bending modes (ZA) in 2D simulations, which is responsible for the thermal contraction of the a-lattice at low temperature. Meanwhile, all the phonon modes are present in the 2D phonon dispersion of ML-MoS2, which indicates that the origin of the ZA mode is not purely due to the out-of-plane movement of atoms and also its effect on thermal expansion is not significant as found in graphene and 2D h-BN.

  1. Rising cost of antidotes in the U.S.: cost comparison from 2010 to 2015.

    PubMed

    Heindel, Gregory A; Trella, Jeanette D; Osterhoudt, Kevin C

    2017-06-01

    Our poison control center observed a large increase in the cost of many antidotes over the past several years. The high cost of antidotes has previously been cited as a factor leading to inadequate antidote supply at some hospitals. Continued increases in the cost of antidotes may lead to further reductions in antidote supply and represent serious concerns. This research aims to quantify recent trends in the costs of antidotes in the U.S. Antidotes and minimum stocking recommendations were retrieved from published guidelines. RED BOOK Online(®) was used to identify the U.S. average wholesale price (AWP) of each antidote in 2010 and 2015. The AWP in 2010 was adjusted using the U.S. Consumer Price Index to adjust for inflation. The cost of minimum stocking levels for each antidote was calculated and compared between the year 2010 and 2015. The cost of stocking many antidotes demonstrated a large increase in AWP from 2010 to 2015. Of the antidotes evaluated, 15 out of 33 had greater than 50% increase in AWP and 8 out of 33 had greater than $1000 increase in AWP. Only four antidotes demonstrated decreases in AWP greater than 10% and only one antidote had its cost of stocking decrease in AWP by more than $1000. The price increase over the last 5 years may further hinder the willingness of hospitals to stock recommended antidotes at adequate quantities. This may impede timely treatment of patients, and negatively impact poisoning outcomes. The price of many antidotes substantially increased in the United States from 2010 to 2015. Strategies should be investigated to help decrease the cost associated with stocking and use of antidotes, including dose rounding, consignment, and regional sharing.

  2. Availability of antidotes in 70 hospitals in Catalonia.

    PubMed

    Broto-Sumalla, Antoni; Rabanal-Tornero, Manel; García-Peláez, Milagros; Aguilar-Salmerón, Raquel; Fernández de Gamarra-Martínez, Edurne; Martínez-Sánchez, Lídia; Gaspar-Caro, María-José; Nogué-Xarau, Santiago

    2017-07-10

    Antidotes may have a relevant role in acute intoxication management and the time until its administration can influence patient survival. Study conducted by a questionnaire sent in early 2015 to 70 hospitals in Catalonia providing emergency services. Qualitative availability on each antidote was considered adequate when present in at least 80% of hospitals. The quantitative availability was considered adequate when at least 80% of hospitals had the number of units of antidote recommended. Lower complexity hospitals (level A) showed a percentage of adequate qualitative and quantitative availability of 66.7 and 42.9% respectively. In higher complexity hospitals (level B) qualitative and quantitative availability was adequate in 64.5 and 38.7% of the antidotes respectively. Data showed no differences between the different health regions as well as a positive correlation (p<.05) between the number of emergencies attended and the percentage of adequate qualitative availability. The availability of antidotes in Catalonia hospitals is generally low and shows differences across health regions and depending on level of complexity. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  3. An Antidote for Acute Cocaine Toxicity

    PubMed Central

    Treweek, Jennifer B.; Janda, Kim D.

    2012-01-01

    Not only has immunopharmacotherapy grown into a field that addresses the abuse of numerous illicit substances, but also the treatment methodologies within immunopharmacotherapy have expanded from traditional active vaccination to passive immunization with anti-drug monoclonal antibodies, optimized mAb formats, and catalytic drug-degrading antibodies. Many laboratories have focused on transitioning distinct immunopharmacotherapeutics to clinical evaluation, but with respect to the indication of cocaine abuse, only the active vaccine TA-CD, which is modeled after our original cocaine hapten GNC1, has been carried through to human clinical trials.2 The successful application of murine mAb GNC92H2 to the reversal of cocaine overdose in a mouse model prompted investigations of human immunoglobulins with the clinical potential to serve as cocaine antidotes. We now report the therapeutic utility of a superior clone, human mAb GNCgzk (Kd = 0.18 nM), which offers a 10-fold improvement in cocaine binding affinity. The GNCgzk manifold was engineered for rapid cocaine clearance, and administration of the F(ab′)2 and Fab formats even after the appearance of acute behavioral signs of cocaine toxicity granted nearly complete prevention of lethality. Thus, contrary to the immunopharmacotherapeutic treatment of drug self-administration, minimal antibody doses were shown to counteract the lethality of a molar excess of circulating cocaine. Passive vaccination with drug-specific antibodies represents a viable treatment strategy for the human condition of cocaine overdose. PMID:22380623

  4. An antidote for acute cocaine toxicity.

    PubMed

    Treweek, Jennifer B; Janda, Kim D

    2012-04-02

    Not only has immunopharmacotherapy grown into a field that addresses the abuse of numerous illicit substances, but also the treatment methodologies within immunopharmacotherapy have expanded from traditional active vaccination to passive immunization with anti-drug monoclonal antibodies, optimized mAb formats, and catalytic drug-degrading antibodies. Many laboratories have focused on transitioning distinct immunopharmacotherapeutics to clinical evaluation, but with respect to the indication of cocaine abuse, only the active vaccine TA-CD, which is modeled after our original cocaine hapten GNC, has been carried through to human clinical trials. The successful application of murine mAb GNC92H2 to the reversal of cocaine overdose in a mouse model prompted investigations of human immunoglobulins with the clinical potential to serve as cocaine antidotes. We now report the therapeutic utility of a superior clone, human mAb GNCgzk (K(d) = 0.18 nM), which offers a 10-fold improvement in cocaine binding affinity. The GNCgzk manifold was engineered for rapid cocaine clearance, and administration of the F(ab')₂ and Fab formats even after the appearance of acute behavioral signs of cocaine toxicity granted nearly complete prevention of lethality. Thus, contrary to the immunopharmacotherapeutic treatment of drug self-administration, minimal antibody doses were shown to counteract the lethality of a molar excess of circulating cocaine. Passive vaccination with drug-specific antibodies represents a viable treatment strategy for the human condition of cocaine overdose.

  5. Dynamics of Vortices in Nano-Structured Superconductors with Periodic Arrays of Various Antidots

    NASA Astrophysics Data System (ADS)

    Fujibayashi, David E.; Kato, Masaru

    2012-12-01

    Stable vortex configurations and its dynamics in superconductors with various types of antidotes are examined, using the molecular dynamics simulation. A pinning potential function, which parameterizes spatial shapes and pinning potential structure of the antidot, is introduced. Dependence of saturation number, which is a maximum number of vortices pinned in a single antidot, on these spatial shape and potential structure are investigated.

  6. Transport and magnetic properties of CMR manganites with antidot arrays

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Du, Kai; Niu, Jiebin; Wei, Wengang; Chen, Jinjie; Yin, Lifeng; Shen, Jian

    2014-03-01

    We fabricated and characterized a series of manganites thin film samples with different densities of antidots. With increasing antidot density, the samples show higher MIT temperature and lower resistivity under zero and low magnetic fields. These differences become smaller and finally vanished when the magnetic field is large enough to melt the charge ordered phase in the system, which is expected in our theoretical explanations. We believe that emerging edge states at the ring of antidotes play a significant role for observed metal-insulator transition and electrical transport properties, which are of great importance of real storage and sensor device design. Magnetic property measurements and theoretical simulation also support the conclusion. These results open up new ways to control and tune the strongly correlated oxides without introduce any new material or field.

  7. Magnetoconductance of a hybrid quantum ring: Effects of antidot potentials

    SciTech Connect

    Kim, Nammee Park, Dae-Han; Kim, Heesang

    2016-05-15

    The electronic structures and two-terminal magnetoconductance of a hybrid quantum ring are studied. The backscattering due to energy-resonance is considered in the conductance calculation. The hybrid magnetic-electric quantum ring is fabricated by applying an antidot electrostatic potential in the middle of a magnetic quantum dot. Electrons are both magnetically and electrically confined in the plane. The antidot potential repelling electrons from the center of the dot plays a critical role in the energy spectra and magnetoconductance. The angular momentum transition in the energy dispersion and the magnetoconductance behavior are investigated in consideration of the antidot potential variation. Results are shown using a comparison of the results of the conventional magnetic quantum dot.

  8. Magnetoconductance of a hybrid quantum ring: Effects of antidot potentials

    NASA Astrophysics Data System (ADS)

    Kim, Nammee; Park, Dae-Han; Kim, Heesang

    2016-05-01

    The electronic structures and two-terminal magnetoconductance of a hybrid quantum ring are studied. The backscattering due to energy-resonance is considered in the conductance calculation. The hybrid magnetic-electric quantum ring is fabricated by applying an antidot electrostatic potential in the middle of a magnetic quantum dot. Electrons are both magnetically and electrically confined in the plane. The antidot potential repelling electrons from the center of the dot plays a critical role in the energy spectra and magnetoconductance. The angular momentum transition in the energy dispersion and the magnetoconductance behavior are investigated in consideration of the antidot potential variation. Results are shown using a comparison of the results of the conventional magnetic quantum dot.

  9. Additive lattice kirigami.

    PubMed

    Castle, Toen; Sussman, Daniel M; Tanis, Michael; Kamien, Randall D

    2016-09-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

  10. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes. PMID:27679822

  11. [Antidotes availability in Emergency Departments of the Italian National Health System and development of a national data-bank on antidotes].

    PubMed

    Locatelli, Carlo; Petrolini, Valeria; Lonati, Davide; Butera, Raffaella; Bove, Angelo; Mela, Lidia; Manzo, Luigi

    2006-01-01

    The availability of antidotes in Italian hospitals has been evaluated through the answers to a specific questionnaire sent to all Italian Emergency Departments, Intensive Care Units, 118 emergency response system, and Poison Centres. Five Poison Centres and, approximately, the 30% of the Emergency Departments and Intensive Care Units of all Italian emergency hospitals answered to the questionnaire. The results point out an insufficient availability of antidotes in the Italian emergency hospitals, with an almost total absence of those necessary for the treatment of less frequent and less known poisonings (e.g. digoxin, industrial agents), also when the antidote is a lifesaving drug. To improve the antidotes availability for the toxicological emergencies and to facilitate its supplying, a "national antidotes data-base" (BaNdA) has been realized, freely available to the hospital services which register themselves and make their antidotes stockpile available.

  12. Antidot shape dependence of switching mechanism in permalloy samples

    NASA Astrophysics Data System (ADS)

    Yetiş, Hakan; Denizli, Haluk

    2017-01-01

    We study antidot shape dependence of the switching magnetization for various permalloy samples with square and triangular arrays of nanometer scale antidots. The remnant magnetization, squareness ratio, and coercive fields of the samples are extracted from the hysteresis loops which are obtained by solving the Landau-Lifshitz-Gilbert (LLG) equation numerically. We find several different magnetic spin configurations which reveal the existence of superdomain wall structures. Our results are discussed in terms of the local shape anisotropy, array geometry, and symmetry properties in order to explain the formation of inhomogeneous domain structures.

  13. CoCrPt antidot arrays with perpendicular magnetic anisotropy made on anodic alumina templates

    NASA Astrophysics Data System (ADS)

    Navas, D.; Ilievski, F.; Ross, C. A.

    2009-06-01

    Ti(5 nm)/CoCrPt(5-20 nm) bilayers with perpendicular magnetic anisotropy were deposited by rf sputtering onto porous alumina films to form antidot arrays with period 105 nm and pore diameters ranging from 18 to 56 nm. The coercivities of the antidot arrays are greater than those of unpatterned films and show only a weak dependence on antidot diameter. Magnetic force microscopy of ac-demagnetized samples shows that the antidot arrays have domain sizes larger than the 105 nm period. The magnetic behavior is discussed in terms of domain wall pinning by the antidots.

  14. National study on the adequacy of antidotes stocking in Lebanese hospitals providing emergency care.

    PubMed

    Mansour, Anthony; Al-Bizri, Layla; El-Maamary, Jad; Al-Helou, Amanda; Hamade, Rayan; Saliba, Elie; Khammash, Dina; Makhoul, Karim; Matli, Kamal; Ghosn, Nada; Deeb, Mary; Faour, Wissam H

    2016-11-07

    Antidotes stocking is a critical component of hospital care for poisoned patients in emergency. Antidote stocking represents a major health challenge worldwide and in Lebanon. Systematic data monitoring of antidote stocking in Lebanese hospitals is lacking. The objective of this study is to assess the adequacy of antidotes stocking in Lebanese hospitals according to type and quantity and explore the characteristics associated with their differential availability. Data collection to assess antidote availability and its correlate was undertaken through a self-administered questionnaire. The questionnaires were distributed by the unit of surveillance at the Ministry of Public Health to eligible hospitals providing emergency care services. The list of essential antidotes was adapted from the World Health Organization (WHO) list and the British Columbia Drug and Poison Information Centre. Among the 85 Lebanese hospitals surveyed none had in stock all the 35 essential antidotes required. The frequency of stocking by type of antidote varied from a minimum of 1.2 % of the hospitals having a (cyanide kit) to 100 % availability of (atropine and calcium gluconate). Teaching hospitals and those with a large bed-capacity reported a higher number of available antidotes for both immediate and non-immediate use than non-teaching hospitals while controlling for the hospital geographical region and public vs private sector. The Lebanese hospitals have a suboptimal stock of essential antidotes supply. It is recommended that the Lebanese Ministry of Public Health monitors closely on the hospital premises the adequacy and availability of essential antidotes stock.

  15. Condensate fraction in a 2D Bose gas measured across the Mott-insulator transition.

    PubMed

    Spielman, I B; Phillips, W D; Porto, J V

    2008-03-28

    We realize a single-band 2D Bose-Hubbard system with Rb atoms in an optical lattice and measure the condensate fraction as a function of lattice depth, crossing from the superfluid to the Mott-insulating phase. We quantitatively identify the location of the superfluid to normal transition by observing when the condensed fraction vanishes. Our measurement agrees with recent quantum Monte Carlo calculations for a finite-sized 2D system to within experimental uncertainty.

  16. Calculation of 2D electronic band structure using matrix mechanics

    NASA Astrophysics Data System (ADS)

    Pavelich, R. L.; Marsiglio, F.

    2016-12-01

    We extend previous work, applying elementary matrix mechanics to one-dimensional periodic arrays (to generate energy bands), to two-dimensional arrays. We generate band structures for the square-lattice "2D Kronig-Penney model" (square wells), the "muffin-tin" potential (circular wells), and Gaussian wells. We then apply the method to periodic arrays of more than one atomic site in a unit cell, specifically to the case of materials with hexagonal lattices like graphene. These straightforward extensions of undergraduate-level calculations allow students to readily determine band structures of current research interest.

  17. Instantons in 2D U(1) Higgs model and 2D CP(N-1) sigma models

    NASA Astrophysics Data System (ADS)

    Lian, Yaogang

    2007-12-01

    In this thesis I present the results of a study of the topological structures of 2D U(1) Higgs model and 2D CP N-1 sigma models. Both models have been studied using the overlap Dirac operator construction of topological charge density. The overlap operator provides a more incisive probe into the local topological structure of gauge field configurations than the traditional plaquette-based operator. In the 2D U(1) Higgs model, we show that classical instantons with finite sizes violate the negativity of topological charge correlator by giving a positive contribution to the correlator at non-zero separation. We argue that instantons in 2D U(1) Higgs model must be accompanied by large quantum fluctuations in order to solve this contradiction. In 2D CPN-1 sigma models, we observe the anomalous scaling behavior of the topological susceptibility chi t for N ≤ 3. The divergence of chi t in these models is traced to the presence of small instantons with a radius of order a (= lattice spacing), which are directly observed on the lattice. The observation of these small instantons provides detailed confirmation of Luscher's argument that such short-distance excitations, with quantized topological charge, should be the dominant topological fluctuations in CP1 and CP 2, leading to a divergent topological susceptibility in the continuum limit. For the CPN-1 models with N > 3 the topological susceptibility is observed to scale properly with the mass gap. Another topic presented in this thesis is an implementation of the Zolotarev optimal rational approximation for the overlap Dirac operator. This new implementation has reduced the time complexity of the overlap routine from O(N3 ) to O(N), where N is the total number of sites on the lattice. This opens up a door to more accurate lattice measurements in the future.

  18. Optoelectronics with 2D semiconductors

    NASA Astrophysics Data System (ADS)

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  19. Structural and functional characterization of a specific antidote for ticagrelor.

    PubMed

    Buchanan, Andrew; Newton, Philip; Pehrsson, Susanne; Inghardt, Tord; Antonsson, Thomas; Svensson, Peder; Sjögren, Tove; Öster, Linda; Janefeldt, Annika; Sandinge, Ann-Sofie; Keyes, Feenagh; Austin, Mark; Spooner, Jennifer; Gennemark, Peter; Penney, Mark; Howells, Garnet; Vaughan, Tristan; Nylander, Sven

    2015-05-28

    Ticagrelor is a direct-acting reversibly binding P2Y12 antagonist and is widely used as an antiplatelet therapy for the prevention of cardiovascular events in acute coronary syndrome patients. However, antiplatelet therapy can be associated with an increased risk of bleeding. Here, we present data on the identification and the in vitro and in vivo pharmacology of an antigen-binding fragment (Fab) antidote for ticagrelor. The Fab has a 20 pM affinity for ticagrelor, which is 100 times stronger than ticagrelor's affinity for its target, P2Y12. Despite ticagrelor's structural similarities to adenosine, the Fab is highly specific and does not bind to adenosine, adenosine triphosphate, adenosine 5'-diphosphate, or structurally related drugs. The antidote concentration-dependently neutralized the free fraction of ticagrelor and reversed its antiplatelet activity both in vitro in human platelet-rich plasma and in vivo in mice. Lastly, the antidote proved effective in normalizing ticagrelor-dependent bleeding in a mouse model of acute surgery. This specific antidote for ticagrelor may prove valuable as an agent for patients who require emergency procedures.

  20. Creativity: Performativity's Poison or Its Antidote?

    ERIC Educational Resources Information Center

    Munday, Ian

    2014-01-01

    A common move in the study of creativity and performativity is to present the former as an antidote to the latter. Might we, therefore, see work on creativity in education as heralding an era of post-performativity? In this paper I argue that the portrayal of performativity in the literature on creativity presents an overly simplistic (vulgar?)…

  1. Creativity: Performativity's Poison or Its Antidote?

    ERIC Educational Resources Information Center

    Munday, Ian

    2014-01-01

    A common move in the study of creativity and performativity is to present the former as an antidote to the latter. Might we, therefore, see work on creativity in education as heralding an era of post-performativity? In this paper I argue that the portrayal of performativity in the literature on creativity presents an overly simplistic (vulgar?)…

  2. Structural and functional characterization of a specific antidote for ticagrelor

    PubMed Central

    Newton, Philip; Pehrsson, Susanne; Inghardt, Tord; Antonsson, Thomas; Svensson, Peder; Sjögren, Tove; Öster, Linda; Janefeldt, Annika; Sandinge, Ann-Sofie; Keyes, Feenagh; Austin, Mark; Spooner, Jennifer; Gennemark, Peter; Penney, Mark; Howells, Garnet; Vaughan, Tristan; Nylander, Sven

    2015-01-01

    Ticagrelor is a direct-acting reversibly binding P2Y12 antagonist and is widely used as an antiplatelet therapy for the prevention of cardiovascular events in acute coronary syndrome patients. However, antiplatelet therapy can be associated with an increased risk of bleeding. Here, we present data on the identification and the in vitro and in vivo pharmacology of an antigen-binding fragment (Fab) antidote for ticagrelor. The Fab has a 20 pM affinity for ticagrelor, which is 100 times stronger than ticagrelor’s affinity for its target, P2Y12. Despite ticagrelor’s structural similarities to adenosine, the Fab is highly specific and does not bind to adenosine, adenosine triphosphate, adenosine 5′-diphosphate, or structurally related drugs. The antidote concentration-dependently neutralized the free fraction of ticagrelor and reversed its antiplatelet activity both in vitro in human platelet-rich plasma and in vivo in mice. Lastly, the antidote proved effective in normalizing ticagrelor-dependent bleeding in a mouse model of acute surgery. This specific antidote for ticagrelor may prove valuable as an agent for patients who require emergency procedures. PMID:25788700

  3. [Antidotes: use guidelines and minimun stock in an emergency department].

    PubMed

    García-Martín, A; Torres Santos-Olmos, R

    2012-01-01

    To develop a guide for antidotes and other medications used to counteract poisoning, and define the stock in an emergency department, as a safety priority for the part-time pharmacist assigned to the unit. A search of specialist databases and web portals of the Spanish Society of Toxicology and the British National Poisons Information Service, as well as toxicology databases, TOXICONET, information from other hospitals, tertiary sources, Micromedex and Medline. The Guide contains 42 active ingredients and is accessible to the Pharmacy and Emergency departments in electronic format. A minimum emergency stock was agreed based on the daily treatment of a 100 kg patient. This information, including updated expiry dates, is available at the emergency department antidote stock facilities and in electronic format. On a monthly basis, the pharmacist reviews the need to replace any drugs, due to their expiry date or lack of use. The lack of evidence from high quality antidote studies, the variability due to the difficulties of updating sources and some geographical differences in their use means that decision-making can be difficult. It would be useful to have minimum quantity recommendations from societies of toxicology, regulatory agencies and organisations such as the Joint Commission on the Accreditation of Healthcare Organisations. It would also be useful to have a suprahospital risk assessment to optimise management and ensure the availability of antidotes which are expensive, have a limited shelf life, or of which demand is difficult to forecast. Copyright © 2011 SEFH. Published by Elsevier Espana. All rights reserved.

  4. Observation of Novel Low-Field FMR modes in Permalloy Antidot Arrays

    NASA Astrophysics Data System (ADS)

    de Long, Lance; Bhat, Vinayak; Farmer, Barry; Woods, Justin; Hastings, Todd; Sklenar, Joseph; Ketterson, John

    2013-03-01

    Permalloy films of thickness 23 nm were patterned with square arrays of square antidots (AD) with feature size D = 120 nm, and lattice constants d = 200, 300, 500 and 700 nm (total sample area = 2 mm x 2mm), using electron beam lithography. Our broad-band (frequencies f = 10 MHz-15 GHz) and narrow-band (9.7 GHz) FMR measurements of even dilute (D/d <<1) AD lattices (ADL) reveal remarkably reproducible absorption spectra in the low-frequency, hysteretic regime in which disordered domain wall (DW) patterns and unsaturated magnetization textures are expected for unpatterned films, but in the present case are strongly affected by the periodic ADL. Other modes in the saturated regime exhibit strong dependence on the angle between the applied DC field H and the ADL axes, as confirmed by our micromagnetic simulations. Novel modes are observed at DC fields above that of the uniform mode, which simulations indicate are localized at AD edges. Other novel modes are observed for DC fields below that of the uniform mode, which simulated power and phase maps indicate are confined to ADL interstices oriented parallel to H. These results show even dilute AD concentrations can effect strong control of DW evolution. Research at Kentucky is supported by U.S. DoE Grant DE-FG02-97ER45653 and NSF Grant EPS-0814194.

  5. Drugs and pharmaceuticals: management of intoxication and antidotes.

    PubMed

    Smith, Silas W

    2010-01-01

    The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of

  6. Extensions of 2D gravity

    SciTech Connect

    Sevrin, A.

    1993-06-01

    After reviewing some aspects of gravity in two dimensions, I show that non-trivial embeddings of sl(2) in a semi-simple (super) Lie algebra give rise to a very large class of extensions of 2D gravity. The induced action is constructed as a gauged WZW model and an exact expression for the effective action is given.

  7. Highly crystalline 2D superconductors

    NASA Astrophysics Data System (ADS)

    Saito, Yu; Nojima, Tsutomu; Iwasa, Yoshihiro

    2017-02-01

    Recent advances in materials fabrication have enabled the manufacturing of ordered 2D electron systems, such as heterogeneous interfaces, atomic layers grown by molecular beam epitaxy, exfoliated thin flakes and field-effect devices. These 2D electron systems are highly crystalline, and some of them, despite their single-layer thickness, exhibit a sheet resistance more than an order of magnitude lower than that of conventional amorphous or granular thin films. In this Review, we explore recent developments in the field of highly crystalline 2D superconductors and highlight the unprecedented physical properties of these systems. In particular, we explore the quantum metallic state (or possible metallic ground state), the quantum Griffiths phase observed in out-of-plane magnetic fields and the superconducting state maintained in anomalously large in-plane magnetic fields. These phenomena are examined in the context of weakened disorder and/or broken spatial inversion symmetry. We conclude with a discussion of how these unconventional properties make highly crystalline 2D systems promising platforms for the exploration of new quantum physics and high-temperature superconductors.

  8. Highly crystalline 2D superconductors

    NASA Astrophysics Data System (ADS)

    Saito, Yu; Nojima, Tsutomu; Iwasa, Yoshihiro

    2016-12-01

    Recent advances in materials fabrication have enabled the manufacturing of ordered 2D electron systems, such as heterogeneous interfaces, atomic layers grown by molecular beam epitaxy, exfoliated thin flakes and field-effect devices. These 2D electron systems are highly crystalline, and some of them, despite their single-layer thickness, exhibit a sheet resistance more than an order of magnitude lower than that of conventional amorphous or granular thin films. In this Review, we explore recent developments in the field of highly crystalline 2D superconductors and highlight the unprecedented physical properties of these systems. In particular, we explore the quantum metallic state (or possible metallic ground state), the quantum Griffiths phase observed in out-of-plane magnetic fields and the superconducting state maintained in anomalously large in-plane magnetic fields. These phenomena are examined in the context of weakened disorder and/or broken spatial inversion symmetry. We conclude with a discussion of how these unconventional properties make highly crystalline 2D systems promising platforms for the exploration of new quantum physics and high-temperature superconductors.

  9. Local Topological Order Inhibits Thermal Stability in 2D

    NASA Astrophysics Data System (ADS)

    Landon-Cardinal, Olivier; Poulin, David

    2013-03-01

    We study the robustness of quantum information stored in the degenerate ground space of a local, frustration-free Hamiltonian with commuting terms on a 2D spin lattice. On one hand, a macroscopic energy barrier separating the distinct ground states under local transformations would protect the information from thermal fluctuations. On the other hand, local topological order would shield the ground space from static perturbations. Here we demonstrate that local topological order implies a constant energy barrier, thus inhibiting thermal stability.

  10. E-2D Advanced Hawkeye Aircraft (E-2D AHE)

    DTIC Science & Technology

    2015-12-01

    and Homeland Defense. As a part of the E-2D AHE radar modernization effort, the Navy also invested in integrating a full glass cockpit and full...Communication Navigation Surveillance/Air Traffic Management capability. The glass cockpit will also provide the capability for the pilot or co-pilot to...hours at a station distance of 200nm Flat Turn Service Ceiling =>25,000 feet above MSL at mission profile =>25,000 feet above MSL at mission

  11. Beam-Plasma Interaction in a 2D Complex Plasma

    NASA Astrophysics Data System (ADS)

    Kyrkos, Stamatios; Kalman, G. J.; Rosenberg, M.

    2006-10-01

    In a complex (dusty) plasma, penetrating ion or electron beams may lead to beam-plasma instabilities. The instability displays interesting new properties when either the plasma or the beam, or both, are strongly interacting^1. Foremost amongst them is the possible generation of transverse instabilities. We consider the case when a 2D plasma is in the crystalline phase, forming a lattice, and the beam is moving in the lattice plane. Both the grains and the beam particles interact through a realistic Yukawa potential. The beam particles are assumed to be weakly coupled to each other and to the lattice^2. Using the full phonon spectrum for a 2D hexagonal Yukawa lattice^3, we determine and compare the transverse and longitudinal growth rates. The behavior of the growth rates depends on the direction of the beam and on the relationship between the beam speed v and the longitudinal and transverse sound speeds sL, sT. For beam speeds between the longitudinal and transverse sound speeds, the transverse instability could be more important, because it appears at lower k values. ^1 G. J. Kalman and M. Rosenberg, J. Phys. A: Math. Gen. 36 5963 (2003) ^2 M. Rosenberg, G. J. Kalman, S. Kyrkos and Z. Donko, J. Phys. A: Math. Gen. 39 4613 (2006) ^3 T. Sullivan, G. J. Kalman, S. Kyrkos, P. Bakshi, M. Rosenberg and Z. Donko, J. Phys. A: Math. Gen. 39 4607 (2006)

  12. Topological lattice actions

    NASA Astrophysics Data System (ADS)

    Bietenholz, W.; Gerber, U.; Pepe, M.; Wiese, U.-J.

    2010-12-01

    We consider lattice field theories with topological actions, which are invariant against small deformations of the fields. Some of these actions have infinite barriers separating different topological sectors. Topological actions do not have the correct classical continuum limit and they cannot be treated using perturbation theory, but they still yield the correct quantum continuum limit. To show this, we present analytic studies of the 1-d O(2) and O(3) model, as well as Monte Carlo simulations of the 2-d O(3) model using topological lattice actions. Some topological actions obey and others violate a lattice Schwarz inequality between the action and the topological charge Q. Irrespective of this, in the 2-d O(3) model the topological susceptibility {χ_t} = {{{left< {{Q^2}} rightrangle }} left/ {V} right.} is logarithmically divergent in the continuum limit. Still, at non-zero distance the correlator of the topological charge density has a finite continuum limit which is consistent with analytic predictions. Our study shows explicitly that some classically important features of an action are irrelevant for reaching the correct quantum continuum limit.

  13. Lattice QCD

    SciTech Connect

    Bornyakov, V.G.

    2005-06-01

    Possibilities that are provided by a lattice regularization of QCD for studying nonperturbative properties of QCD are discussed. A review of some recent results obtained from computer calculations in lattice QCD is given. In particular, the results for the QCD vacuum structure, the hadron mass spectrum, and the strong coupling constant are considered.

  14. [Modern approaches to the formation of antidote stocks at medical institutions in Russia and foreign countries].

    PubMed

    Simonenko, V E; Sarmanaev, S Kh; Kovalev, E V; Sarmanaeva, R R; Kukhanov, A V

    2014-11-01

    This article analyses the approaches to the formation of specific treatment of acute poisoning in the various countries. The authors present a systematic review of scientific publications about the formation of reserves of antidote agents at medical institutions of the Russian Federation, the US, Canada, France, Spain, Greece, Norway, Czech Republic, Taiwan and Poland. A search for a variety of databases, as well as by reviewing reference lists of publications on the subject of "stockpiling antidote means". It is concluded that the antidote provision at health care institutions in different countries is insufficient. State of affairs with the formation of antidote stocks is better at hospitals of Czech Republic, France and Spain. To determine the range and volume of the stock of fixed assets necessary antidote coordination and approval of the list and the number of mandatory for every medical institution antidotes.

  15. Observation of Spin-Orbit Berry’s Phase in Magnetoresistance of a Two-Dimensional Hole Anti-dot System

    NASA Astrophysics Data System (ADS)

    Kang, Ning; Abe, Eisuke; Hashimoto, Yoshiaki; Iye, Yasuhiro; Katsumoto, Shingo

    2007-08-01

    We report a study of the Aharonov-Bohm (AB) type oscillation of weak field magnetoresistance in an anti-dot lattice (ADL) of a two-dimensional hole system in the presence of strong spin-orbit interaction. The Fourier transform of the oscillations reveals non-monotonic evolutions with the different range of harmonic component, which are indicative of the existence of additional phase factors. A simulation considering Berry’s phase and the phase arising from the spin-orbit shift in the momentum space shows qualitative agreement with the experiment.

  16. 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

  17. Effect of Anti-dots on the Magnetic Susceptibility in a Superconducting Long Prism

    NASA Astrophysics Data System (ADS)

    Aguirre, C. A.; Joya, Miryam R.; Barba-Ortega, J.

    2017-02-01

    The magnetic susceptibility of a long mesoscopic superconducting square prism containing one/two (dot) anti-dots is calculated in the framework of the Ginzburg-Landau theoretical model. This magnetic susceptibility shows jumps at each of the vortex transition fields. We studied the influence of the number, size and geometry of the anti-dots on the magnetic susceptibility in a superconducting sample. We found interesting physical behavior when several kinds of materials filled into the anti-dot are considered.

  18. A specific antidote for reversal of anticoagulation by direct and indirect inhibitors of coagulation factor Xa.

    PubMed

    Lu, Genmin; DeGuzman, Francis R; Hollenbach, Stanley J; Karbarz, Mark J; Abe, Keith; Lee, Gail; Luan, Peng; Hutchaleelaha, Athiwat; Inagaki, Mayuko; Conley, Pamela B; Phillips, David R; Sinha, Uma

    2013-04-01

    Inhibitors of coagulation factor Xa (fXa) have emerged as a new class of antithrombotics but lack effective antidotes for patients experiencing serious bleeding. We designed and expressed a modified form of fXa as an antidote for fXa inhibitors. This recombinant protein (r-Antidote, PRT064445) is catalytically inactive and lacks the membrane-binding γ-carboxyglutamic acid domain of native fXa but retains the ability of native fXa to bind direct fXa inhibitors as well as low molecular weight heparin-activated antithrombin III (ATIII). r-Antidote dose-dependently reversed the inhibition of fXa by direct fXa inhibitors and corrected the prolongation of ex vivo clotting times by such inhibitors. In rabbits treated with the direct fXa inhibitor rivaroxaban, r-Antidote restored hemostasis in a liver laceration model. The effect of r-Antidote was mediated by reducing plasma anti-fXa activity and the non-protein bound fraction of the fXa inhibitor in plasma. In rats, r-Antidote administration dose-dependently and completely corrected increases in blood loss resulting from ATIII-dependent anticoagulation by enoxaparin or fondaparinux. r-Antidote has the potential to be used as a universal antidote for a broad range of fXa inhibitors.

  19. Fibonacci Optical Lattices

    NASA Astrophysics Data System (ADS)

    Singh, Kevin; Geiger, Zachary; Senaratne, Ruwan; Rajagopal, Shankari; Fujiwara, Kurt; Weld, David; Weld Group Team

    2015-05-01

    Quasiperiodicity is intimately involved in quantum phenomena from localization to the quantum Hall effect. Recent experimental investigation of quasiperiodic quantum effects in photonic and electronic systems have revealed intriguing connections to topological phenomena. However, such experiments have been limited by the absence of techniques for creating tunable quasiperiodic structures. We propose a new type of quasiperiodic optical lattice, constructed by intersecting a Gaussian beam with a 2D square lattice at an angle with an irrational tangent. The resulting potential, a generalization of the Fibonacci lattice, is a physical realization of the mathematical ``cut-and-project'' construction which underlies all quasiperiodic structures. Calculation of the energies and wavefunctions of atoms loaded into the proposed quasiperiodic lattice demonstrate a fractal energy spectrum and the existence of edge states. We acknowledge support from the ONR (award N00014-14-1-0805), the ARO and the PECASE program (award W911NF-14-1-0154), the AFOSR (award FA9550-12-1-0305), and the Alfred P. Sloan foundation (grant BR2013-110).

  20. Selection of an aptamer antidote to the anticoagulant drug bivalirudin.

    PubMed

    Martin, Jennifer A; Parekh, Parag; Kim, Youngmi; Morey, Timothy E; Sefah, Kwame; Gravenstein, Nikolaus; Dennis, Donn M; Tan, Weihong

    2013-01-01

    Adverse drug reactions, including severe patient bleeding, may occur following the administration of anticoagulant drugs. Bivalirudin is a synthetic anticoagulant drug sometimes employed as a substitute for heparin, a commonly used anticoagulant that can cause a condition called heparin-induced thrombocytopenia (HIT). Although bivalrudin has the advantage of not causing HIT, a major concern is lack of an antidote for this drug. In contrast, medical professionals can quickly reverse the effects of heparin using protamine. This report details the selection of an aptamer to bivalirudin that functions as an antidote in buffer. This was accomplished by immobilizing the drug on a monolithic column to partition binding sequences from nonbinding sequences using a low-pressure chromatography system and salt gradient elution. The elution profile of binding sequences was compared to that of a blank column (no drug), and fractions with a chromatographic difference were analyzed via real-time PCR (polymerase chain reaction) and used for further selection. Sequences were identified by 454 sequencing and demonstrated low micromolar dissociation constants through fluorescence anisotropy after only two rounds of selection. One aptamer, JPB5, displayed a dose-dependent reduction of the clotting time in buffer, with a 20 µM aptamer achieving a nearly complete antidote effect. This work is expected to result in a superior safety profile for bivalirudin, resulting in enhanced patient care.

  1. Photostability of antidotal oxime HI-6, impact on drug development.

    PubMed

    Bogan, Reinhard; Worek, Franz; Koller, Marianne; Klaubert, Bernd

    2012-01-01

    HI-6 exhibits superior efficacy in the therapy of intoxication by different highly toxic organophosphorus nerve agents. Therefore HI-6 is a promising candidate for the development of new antidotes against nerve agents. For ethical and safety reasons antidotes containing HI-6 should get marketing authorization. Active pharmaceutical ingredients of medicinal products have to fulfil regulatory conditions in terms of purity and stability. Photostability is an essential parameter in this testing strategy. HI-6 was tested under conditions of ICH Q1B 'Photostability testing of new drug substances and products'. The data showed a marked degradation of HI-6 after exposure to daylight. The mechanism of degradation could be detected as photoisomerism. The light burden dependent rate of photoisomerism was followed quantitatively. Based on these quantitative results on the amount of light induced isomeric product a pharmacological qualification was made. A standardized in vitro test showed a decreased ability of light exposed HI-6 to reactivate sarin- and paraoxon-inhibited human acetylcholinesterase. These results have an impact on the further development of antidotes containing HI-6, as light protection will probably be necessary during handling, packaging, storage and application.

  2. Experimental investigations on the antidotal treatment of nifedipine overdosage.

    PubMed

    Strubelt, O; Diederich, K W

    1986-01-01

    Rats anesthetized with pentobarbital and ventilated artificially were infused with 0.5 mg/kg X min nifedipine. They exhibited a sharp decline of blood pressure, heart rate, cardiac output and peripheral resistance and died after 62.3 +/- 5.3 min of infusion. In the ECG, sinus bradycardia followed by AV-dissociation and an escape rhythm originating from the AV-node or the bundle of His occurred. The survival time of nifedipine-infused rats increased by 100% and more upon additional infusion with calcium chloride, calcium gluconate, isoproterenol or dopamine and by 50% after prenalterol. Epinephrine, norepinephrine, angiotensin amide and the plasma expander polygeline were ineffective in this respect. All drugs prolonging the survival time elevated the cardiac output. Ca++ and dopamine also increased the blood pressure whereas isoproterenol accelerated the escape rhythm. Similar cardiovascular changes as in rats occurred in rabbits infused with 0.2 mg/kg X min nifedipine, the survival time without antidotal treatment amounting to 46.3 +/- 7.9 min. Calcium chloride more than doubled the survival time in rabbits, too, but isoproterenol and dopamine proved to be ineffective. Excess calcium did not overcome the inhibitory effects of nifedipine on pacemaker activity, atrioventricular conduction and peripheral resistance. The antidotal efficacy of calcium appears to be attributable to a reversal of the negative inotropic activity of nifedipine. In conclusion, Ca++ seems to be the drug of choice for the antidotal treatment of nifedipine intoxication.

  3. Antidotal treatment of the acute cardiovascular toxicity of verapamil.

    PubMed

    Strubelt, O

    1984-09-01

    Rats anaesthetized with pentobarbital and ventilated artificially were infused with 0.15 mg/kg/min. verapamil; without antidotal treatment, they died after 51.1+/-7.1 min. The survival time more than trebled upon an additional infusion with calcium chloride, epinephrine, isoprenaline, orciprenaline or prenalterol and nearly doubled upon administration of a plasma expander. It was not increased, however, by treatment with angiotensin or atropine. The infusion of verapamil declined the arterial blood pressure by 75%, and heart rate, cardiac output and peripheral resistance by about 50%; in the ECG, sinus bradycardia followed by AV-dissociation with nodal rhythm occurred. All antidotes that raised the lethal dose of verapamil increased the cardiac output. Calcium and the sympathomimetics with alpha-adrenergic activity also counteracted the verapamil-induced hypotension. Calcium did not influence the ECG alterations produced by verapamil, while the sympathomimetics restored the sinus rhythm or accelerated the nodal pacemaker. Calcium, epinephrine and isoprenaline also antagonized the strong decrease of left-ventricular dp/dt max. induced by verapamil. In conclusion, calcium as well as sympathomimetic amines are potent antidotes against the cardiovascular toxicity of verapamil, the latter being superior to calcium in their ability to improve pacemaker activity and AV-conduction.

  4. Observation of a hole-size-dependent energy shift of the surface-plasmon resonance in Ni antidot thin films

    SciTech Connect

    Fang, H.; Akinoglu, E. M.; Fumagalli, P.; Caballero, B.; García-Martín, A.; Papaioannou, E. Th.; Cuevas, J. C.; Giersig, M.

    2015-04-13

    A combined experimental and theoretical study of the magneto-optic properties of a series of nickel antidot thin films is presented. The hole diameter varies from 869 down to 636 nm, while the lattice periodicity is fixed at 920 nm. This results in an overall increase of the polar Kerr rotation with decreasing hole diameter due to the increasing surface coverage with nickel. In addition, at photon energies of 2.7 and 3.3 eV, where surface-plasmon excitations are expected, we observe distinct features in the polar Kerr rotation not present in continuous nickel films. The spectral position of the peaks exhibits a red shift with decreasing hole size. This is explained within the context of an effective medium theory by a change in the effective dielectric function of the Ni thin films.

  5. One-atom-thick 2D copper oxide clusters on graphene.

    PubMed

    Kano, Emi; Kvashnin, Dmitry G; Sakai, Seiji; Chernozatonskii, Leonid A; Sorokin, Pavel B; Hashimoto, Ayako; Takeguchi, Masaki

    2017-03-17

    The successful isolation and remarkable properties of graphene have recently triggered investigation of two-dimensional (2D) materials from layered compounds; however, one-atom-thick 2D materials without bulk layered counterparts are scarcely reported. Here we report the structure and properties of novel 2D copper oxide studied by experimental and theoretical methods. Electron microscopy observations reveal that copper oxide can form monoatomic layers with an unusual square lattice on graphene. Density functional theory calculations suggest that oxygen atoms at the centre of the square lattice stabilizes the 2D Cu structure, and that the 2D copper oxide sheets have unusual electronic and magnetic properties different from 3D bulk copper oxide.

  6. In-plane spin wave modes in permalloy antidot arrays observation and analysis

    NASA Astrophysics Data System (ADS)

    Yu, Chengtao; Mankey, Gary

    2005-03-01

    Previously, we have reported demagnetization field induced localized modes[1] in-plane at 35 GHz ferromagnetic resonance, and dipolar-exchange governed lateral standing spin waves out-of-plane at 9.7 GHz in permalloy antidots. Here we present in-plane investigations at 9.7 GHz on various hole arrays (hole diameter 1.5μm; hole lattice 3μm x 3, 4, 5, and 7μm). In addition to the two main localized modes, which arise from regions confined by holes along the long axis and short axis (region A and B, respectively), spin wave manifolds pertinent to each peak are identified. Owing to the confinement imposed by the holes as well as the demagnetization field, region A and B exhibit distinct resonance geometry. For instance, for field along short axis, region A and B are in Damon-Esbach and magnetostatic backward volume mode geometry respectively, with the spin wave vectors determined by hole separations along long and short axis. This is reversed with field along long axis. The dispersion of the observed spin waves is analyzed accordingly. Supported by US DOE FG02-86ER45281 (MU) and NSF DMR-0213985 (UA). ^1Chengtao Yu, Michael J. Pechan, G. J. Mankey, Appl. Phys. Lett. 83, 3948 (2003).

  7. Valleytronics in 2D materials

    NASA Astrophysics Data System (ADS)

    Schaibley, John R.; Yu, Hongyi; Clark, Genevieve; Rivera, Pasqual; Ross, Jason S.; Seyler, Kyle L.; Yao, Wang; Xu, Xiaodong

    2016-11-01

    Semiconductor technology is currently based on the manipulation of electronic charge; however, electrons have additional degrees of freedom, such as spin and valley, that can be used to encode and process information. Over the past several decades, there has been significant progress in manipulating electron spin for semiconductor spintronic devices, motivated by potential spin-based information processing and storage applications. However, experimental progress towards manipulating the valley degree of freedom for potential valleytronic devices has been limited until very recently. We review the latest advances in valleytronics, which have largely been enabled by the isolation of 2D materials (such as graphene and semiconducting transition metal dichalcogenides) that host an easily accessible electronic valley degree of freedom, allowing for dynamic control.

  8. Unparticle example in 2D.

    PubMed

    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.

  9. Cyanide antidotes for mass casualties: water-soluble salts of the dithiane (sulfanegen) from 3-mercaptopyruvate for intramuscular administration.

    PubMed

    Patterson, Steven E; Monteil, Alexandre R; Cohen, Jonathan F; Crankshaw, Daune L; Vince, Robert; Nagasawa, Herbert T

    2013-02-14

    Current cyanide antidotes are administered by IV infusion, which is suboptimal for mass casualties. Therefore, in a cyanide disaster, intramuscular (IM) injectable antidotes would be more appropriate. We report the discovery of the highly water-soluble sulfanegen triethanolamine as a promising lead for development as an IM injectable cyanide antidote.

  10. Cyanide Antidotes for Mass Casualties: Water-Soluble Salts of the Dithiane (Sulfanegen) from 3-Mercaptopyruvate for Intramuscular Administration

    PubMed Central

    Patterson, Steven E.; Monteil, Alexandre R.; Cohen, Jonathan F.; Crankshaw, Daune L.; Vince, Robert; Nagasawa, Herbert T.

    2013-01-01

    Current cyanide antidotes are administered by IV infusion which is suboptimal for mass casualties. Therefore, in a cyanide disaster intramuscular (IM) injectable antidotes would be more appropriate. We report the discovery of the highly water-soluble sulfanegen triethanolamine as a promising lead for development as an IM injectable cyanide antidote. PMID:23301495

  11. Shear viscosity measurements in a 2D Yukawa liquid

    NASA Astrophysics Data System (ADS)

    Nosenko, Volodymyr

    2005-03-01

    Shear viscosity was measured for a 2D strongly-coupled Yukawa liquid. First, we formed a dilute monolayer suspension of microspheres in a partially-ionized rarefied gas, i.e., a dusty plasma. In the absence of manipulation, the suspension forms a 2D triangular lattice. We used a new in-situ method of applying a shear stress using the scattering forces applied by counter-propagating laser beams. The lattice melted and a shear flow formed. Using digital video microscopy for direct imaging and particle tracking, the microscopic dynamics of the shear flow are observed. Averaging the velocities of individual microspheres, a velocity flow profile was calculated. Using the Navier-Stokes equation with an additional frictional term to account for gas drag, we fit the velocity profile. The fit yielded the value of the shear viscosity. The kinematic viscosity of our particle suspension is of order 1 mm^2s-1, which is comparable to that for liquid water. We believe this is the first report of a rheological measurement in a 2D dusty plasma. This talk is based on V. Nosenko and J. Goree, PRL 93, 155004 (2004).

  12. An automated pipeline to screen membrane protein 2D crystallization

    PubMed Central

    Kim, Changki; Vink, Martin; Hu, Minghui; Love, James; Stokes, David L.; Ubarretxena-Belandia, Iban

    2011-01-01

    Electron crystallography relies on electron cryomicroscopy of two-dimensional (2D) crystals and is particularly well suited for studying the structure of membrane proteins in their native lipid bilayer environment. To obtain 2D crystals from purified membrane proteins, the detergent in a protein-lipid-detergent ternary mixture must be removed, generally by dialysis, under conditions favoring reconstitution into proteoliposomes and formation of well-ordered lattices. To identify these conditions a wide range of parameters such as pH, lipid composition, lipid-to-protein ratio, ionic strength and ligands must be screened in a procedure involving four steps: crystallization, specimen preparation for electron microscopy, image acquisition, and evaluation. Traditionally, these steps have been carried out manually and, as a result, the scope of 2D crystallization trials has been limited. We have therefore developed an automated pipeline to screen the formation of 2D crystals. We employed a 96-well dialysis block for reconstitution of the target protein over a wide range of conditions designed to promote crystallization. A 96-position magnetic platform and a liquid handling robot were used to prepare negatively stained specimens in parallel. Robotic grid insertion into the electron microscope and computerized image acquisition ensures rapid evaluation of the crystallization screen. To date, 38 2D crystallization screens have been conducted for 15 different membrane proteins, totaling over 3000 individual crystallization experiments. Three of these proteins have yielded diffracting 2D crystals. Our automated pipeline outperforms traditional 2D crystallization methods in terms of throughput and reproducibility. PMID:20349145

  13. Antidotes and treatments for chemical warfare/terrorism agents: an evidence-based review.

    PubMed

    Rodgers, G C; Condurache, C T

    2010-09-01

    This article reviews the evidence supporting the efficacy of antidotes used or recommended for the potential chemical warfare agents of most concern. Chemical warfare agents considered include cyanide, vesicants, pulmonary irritants such as chlorine and phosgene, and nerve agents. The strength of evidence for most antidotes is weak, highlighting the need for additional research in this area.

  14. Meso- and racemic-DMSA as Antidotes in Heavy Metal Poisoning

    DTIC Science & Technology

    2001-09-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP013383 TITLE: Meso- and racemic-DMSA as Antidotes in Heavy Metal Poisoning...comprise the compilation report: ADP013371 thru ADP013468 UNCLASSIFIED 13. Meso- AND racemic-DMSA AS ANTIDOTES IN HEAVY METAL POISONING 1Maja Blanu~a

  15. Magnetic hardening and domain structure in Co/Pt antidots with perpendicular anisotropy

    NASA Astrophysics Data System (ADS)

    Bran, C.; Gawronski, P.; Lucas, I.; del Real, R. P.; Strichovanec, P.; Asenjo, A.; Vazquez, M.; Chubykalo-Fesenko, O.

    2017-02-01

    (Co(0.4 nm)/Pt(0.7 nm)) x (x  =  10, 20, 30) multilayer antidot thin films (films with arrays of nanoholes) have been grown by dc sputtering onto self-assembled pores of anodic alumina membranes with a tailored diameter and a fixed inter-hole distance. The magnetic behavior has been quantified by vibrating sample magnetometry, and the surface magnetization patterns have been imaged by magnetic force microscopy. The magnetization reversal mechanism is characterized by two steps depending on the film thickness and antidot diameter. These steps are ascribed to the nucleation and demagnetization of magnetic stripe domains. Their presence confirms the perpendicular anisotropy of the multilayer antidot films. The coercivity of antidot thin film is larger than that of the continuous films due to additional pinning centers provided by antidots. The width of the stripe domains increases as a function of film thickness. The demagnetization is further investigated through micromagnetic simulations that are in agreement with the measured hysteresis loops and their features. Different reversal mechanisms and an increase of the domain width in antidot thin films are also confirmed as a function of the magnetic anisotropy, antidot diameter and thickness of the thin film. The presence of antidots with a designed geometry is revealed to be successful in tailoring the coercivity of the thin films and magnetic patterns, which is relevant for advances in nanoscale technologies.

  16. Quantum coherence selective 2D Raman-2D electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-03-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  17. Quantum coherence selective 2D Raman–2D electronic spectroscopy

    PubMed Central

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-01-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational–vibrational, electronic–vibrational and electronic–electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment–protein complexes. PMID:28281541

  18. Quantum coherence selective 2D Raman-2D electronic spectroscopy.

    PubMed

    Spencer, Austin P; Hutson, William O; Harel, Elad

    2017-03-10

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  19. Subwavelength Lattice Optics by Evolutionary Design

    PubMed Central

    2015-01-01

    This paper describes a new class of structured optical materials—lattice opto-materials—that can manipulate the flow of visible light into a wide range of three-dimensional profiles using evolutionary design principles. Lattice opto-materials are based on the discretization of a surface into a two-dimensional (2D) subwavelength lattice whose individual lattice sites can be controlled to achieve a programmed optical response. To access a desired optical property, we designed a lattice evolutionary algorithm that includes and optimizes contributions from every element in the lattice. Lattice opto-materials can exhibit simple properties, such as on- and off-axis focusing, and can also concentrate light into multiple, discrete spots. We expanded the unit cell shapes of the lattice to achieve distinct, polarization-dependent optical responses from the same 2D patterned substrate. Finally, these lattice opto-materials can also be combined into architectures that resemble a new type of compound flat lens. PMID:25380062

  20. Negative-viscosity lattice gases

    SciTech Connect

    Rothman, D.H. )

    1989-08-01

    A new irreversible collision rule is introduced for lattice-gas automata. The rule maximizes the flux of momentum in the direction of the local momentum gradient, yielding a negative shear viscosity. Numerically results in 2D show that the negative viscosity leads to the spontaneous ordering of the velocity field, with vorticity resolvable down to one lattice-link length. The new rule may be used in conjunction with previously proposed collision rules to yield a positive shear viscosity lower than the previous rules provide. In particular, Poiseuille flow tests demonstrate a decrease in viscosity by more than a factor of 2.

  1. [Antidotes and medicines used to treat poisoning in Brazil: needs, availability and opportunities].

    PubMed

    Galvão, Tais F; Bucaretchi, Fabio; De Capitani, Eduardo M; Pereira, Maurício G; Silva, Marcus T

    2013-11-01

    Antidotes and certain other drugs are essential for treating some types of poisoning. Failures in their supply can jeopardize the population's health and safety. The current study aimed to assess the availability of antidotes and other drugs used in the treatment of poisonings in Brazil. International guidelines were used as the basis for selecting 41 antidotes for analysis, none of which currently protected by patents. Of these, 27 are registered in Brazil, but 11 of these are available in inadequate forms for treating poisoning, leaving 16 commercially available antidotes. Only one-third of the drugs needed for treating poisoning are included in the country's list of essential drugs. The article also presents a proposal for supplying the demand for one of the antidotes, anti-digoxin antibody, considering Brazil's domestic capacity for manufacturing immunobiologicals. The study's results show the limitations to adequate treatment for poison victims in Brazil and reinforce the urgent need to strengthen public policies in this area.

  2. Antidote control of aptamer therapeutics: the road to a safer class of drug agents.

    PubMed

    Bompiani, K M; Woodruff, R S; Becker, R C; Nimjee, S M; Sullenger, B A

    2012-08-01

    Aptamers, or nucleic acid ligands, have gained clinical interest over the past 20 years due to their unique characteristics, which are a combination of the best facets of small molecules and antibodies. The high binding affinity and specificity of aptamers allows for isolation of an artificial ligand for theoretically any therapeutic target of interest. Chemical manipulations of aptamers also allow for fine-tuning of their bioavailability, and antidote control greatly expands their clinical use. Here we review the various methods of antidote control of aptamer therapeutics--matched oligonucleotide antidotes and universal antidotes. We also describe the development, recent progress, and potential future therapeutic applications of these types of aptamer-antidote pairs.

  3. Magnetic Property in large array cobalt antidot thin film using polymer-assisted nanosphere lithography

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Li; Ho, Chi-Chih; Hsieh, Yung-Wu; Juan, Wen-Tau; Lin, Keng-Hui

    2010-03-01

    We have developed a new method to prepare monolayer of close- packed nanospheres (NSs) over large area onto a substrate of any kind utilizing polymer bridging effect. The NSs packing domain can be as large as 1 cmx1 cm which is demonstrated from its diffraction pattern. It was then used as a template to fabricate series of cobalt antidot thin films with different antidot diameter ranging from 100nm to 180nm. Because of the good periodicity and less defects in our nanostructured samples, we would be able to not only qualitatively study their magnetic properties but also quantitatively. As the antidot diameter increases, the surface to bulk volume fraction increases and the surface magnetism becomes more prominent. We found a systematic increase in magnetic coercivity with the antidote diameter, while the saturation magnetization drops at large antidote diameter. Detailed analysis and their implication will be discussed.

  4. Vibrational Properties of a Two-Dimensional Silica Kagome Lattice

    PubMed Central

    2016-01-01

    Kagome lattices are structures possessing fascinating magnetic and vibrational properties, but in spite of a large body of theoretical work, experimental realizations and investigations of their dynamics are scarce. Using a combination of Raman spectroscopy and density functional theory calculations, we study the vibrational properties of two-dimensional silica (2D-SiO2), which has a kagome lattice structure. We identify the signatures of crystalline and amorphous 2D-SiO2 structures in Raman spectra and show that, at finite temperatures, the stability of 2D-SiO2 lattice is strongly influenced by phonon–phonon interaction. Our results not only provide insights into the vibrational properties of 2D-SiO2 and kagome lattices in general but also suggest a quick nondestructive method to detect 2D-SiO2. PMID:28024359

  5. Vibrational Properties of a Two-Dimensional Silica Kagome Lattice.

    PubMed

    Björkman, Torbjörn; Skakalova, Viera; Kurasch, Simon; Kaiser, Ute; Meyer, Jannik C; Smet, Jurgen H; Krasheninnikov, Arkady V

    2016-12-27

    Kagome lattices are structures possessing fascinating magnetic and vibrational properties, but in spite of a large body of theoretical work, experimental realizations and investigations of their dynamics are scarce. Using a combination of Raman spectroscopy and density functional theory calculations, we study the vibrational properties of two-dimensional silica (2D-SiO2), which has a kagome lattice structure. We identify the signatures of crystalline and amorphous 2D-SiO2 structures in Raman spectra and show that, at finite temperatures, the stability of 2D-SiO2 lattice is strongly influenced by phonon-phonon interaction. Our results not only provide insights into the vibrational properties of 2D-SiO2 and kagome lattices in general but also suggest a quick nondestructive method to detect 2D-SiO2.

  6. 2D transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Manzeli, Sajedeh; Ovchinnikov, Dmitry; Pasquier, Diego; Yazyev, Oleg V.; Kis, Andras

    2017-08-01

    Graphene is very popular because of its many fascinating properties, but its lack of an electronic bandgap has stimulated the search for 2D materials with semiconducting character. Transition metal dichalcogenides (TMDCs), which are semiconductors of the type MX2, where M is a transition metal atom (such as Mo or W) and X is a chalcogen atom (such as S, Se or Te), provide a promising alternative. Because of its robustness, MoS2 is the most studied material in this family. TMDCs exhibit a unique combination of atomic-scale thickness, direct bandgap, strong spin-orbit coupling and favourable electronic and mechanical properties, which make them interesting for fundamental studies and for applications in high-end electronics, spintronics, optoelectronics, energy harvesting, flexible electronics, DNA sequencing and personalized medicine. In this Review, the methods used to synthesize TMDCs are examined and their properties are discussed, with particular attention to their charge density wave, superconductive and topological phases. The use of TMCDs in nanoelectronic devices is also explored, along with strategies to improve charge carrier mobility, high frequency operation and the use of strain engineering to tailor their properties.

  7. Antidotal effect of dihydroxyacetone against cyanide toxicity in vivo.

    PubMed

    Niknahad, H; O'Brien, P J

    1996-05-01

    Potassium cyanide (CN) intoxication in mice was found to be effectively antagonized by dihydroxyacetone (DHA), particularly if administered in combination with another CN antidote, sodium thiosulfate. Cyanide-induced convulsions were also prevented by DHA treatment, either alone or in combination with thiosulfate. Injection (i.p.) of DHA (2 g/kg) 2 min after or 10 min before CN (s.c.) increased LD50 values of CN(8.7 mg/kg) by factors of 2.1 and 3.0, respectively. Treatment with a combination of DHA and thiosulfate after CN increased the LD50 by a factor of 2.4. Pretreatment with a combination of DHA and thiosulfate (1 g/kg) increased the LD50 of CN to 83 mg/kg. Administration of alpha-ketoglutarate (2.0 g/kg), but not pyruvate, 2 min after CN increased the LD50 of CN by a factor of 1.6. Brain, heart and liver cytochrome oxidase activities were also measured following in vivo CN treatment with and without DHA. Pretreatment with DHA prevented the inhibition of cytochrome oxidase activity by CN and treatment with DHA after CN accelerated the recovery of cytochrome oxidase activity, especially in brain and heart homogenates. DHA is a physiological agent and, therefore, could prove to be a safe and effective antidote for CN, particularly in cases of fire smoke inhalation in which a combination of CN and carbon monoxide is present. In these cases the normally used antidote, sodium nitrite, to induce methemoglobin so as to trap the CN, is contraindicated because some of the oxygen-carrying capacity of the blood will have already been diminished by carbon monoxide.

  8. Optical diffraction by ordered 2D arrays of silica microspheres

    NASA Astrophysics Data System (ADS)

    Shcherbakov, A. A.; Shavdina, O.; Tishchenko, A. V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.

    2017-03-01

    The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality.

  9. 2D photonic crystal and its angular reflective azimuthal spectrum

    NASA Astrophysics Data System (ADS)

    Senderakova, Dagmar; Drzik, Milan; Tomekova, Juliana

    2016-12-01

    Contemporary, attention is paid to photonic crystals, which can strongly modify light propagation through them and enable a controllable light manipulation. The contribution is focused on a sub-wavelength 2D structure formed by Al2O3 layer on silicon substrate, patterned with periodic hexagonal lattice of deep air holes. Using various laser sources of light at single wavelength, azimuthal angle dependence of the mirror-like reflected light intensity was recorded photo-electrically. The results obtained can be used to sample the band-structure of leaky modes of the photonic crystal more reliably and help us to map the photonic dispersion diagram.

  10. Lattice overview

    SciTech Connect

    Creutz, M.

    1984-01-01

    After reviewing some recent developments in supercomputer access, the author discusses a few areas where perturbation theory and lattice gauge simulations make contact. The author concludes with a brief discussion of a deterministic dynamics for the Ising model. This may be useful for numerical studies of nonequilibrium phenomena. 13 references.

  11. Non-trivial θ-vacuum effects in the 2-d O(3) model

    NASA Astrophysics Data System (ADS)

    Bögli, M.; Niedermayer, F.; Pepe, M.; Wiese, U.-J.

    2012-04-01

    We study θ-vacua in the 2-d lattice O(3) model using the standard action and an optimized constraint action with very small cut-off effects, combined with the geometric topological charge. Remarkably, dislocation lattice artifacts do not spoil the non-trivial continuum limit at θ ne 0 , and there are different continuum theories for each value 0 ≤ θ ≤ π. A very precise Monte Carlo study of the step scaling function indirectly confirms the exact S-matrix of the 2-d O(3) model at θ = π.

  12. Computational identification of promising thermoelectric materials among known quasi-2D binary compounds

    SciTech Connect

    Gorai, Prashun; Toberer, Eric S.; Stevanović, Vladan

    2016-01-01

    Quasi low-dimensional structures are abundant among known thermoelectric materials, primarily because of their low lattice thermal conductivities. In this work, we have computationally assessed the potential of 427 known binary quasi-2D structures in 272 different chemistries for thermoelectric performance. To assess the thermoelectric performance, we employ an improved version of our previously developed descriptor for thermoelectric performance [Yan et al., Energy Environ. Sci., 2015, 8, 983]. The improvement is in the explicit treatment of van der Waals interactions in quasi-2D materials, which leads to significantly better predictions of their crystal structures and lattice thermal conductivities. The improved methodology correctly identifies known binary quasi-2D thermoelectric materials such as Sb2Te3, Bi2Te3, SnSe, SnS, InSe, and In2Se3. As a result, we propose candidate quasi-2D binary materials, a number of which have not been previously considered for thermoelectric applications.

  13. Interfacing graphene and related 2D materials with the 3D world.

    PubMed

    Tománek, David

    2015-04-10

    An important prerequisite to translating the exceptional intrinsic performance of 2D materials such as graphene and transition metal dichalcogenides into useful devices precludes their successful integration within the current 3D technology. This review provides theoretical insight into nontrivial issues arising from interfacing 2D materials with 3D systems including epitaxy and ways to accommodate lattice mismatch, the key role of contact resistance and the effect of defects in electrical and thermal transport.

  14. [Decontamination and antidotes in acute cases of poisoning].

    PubMed

    Kupferschmidt, Hugo; Züst, Ariane; Rauber-Lüthy, Christine

    2009-05-01

    In acute poisoning the maintenance or reconstitution of vital functions is the first and most critical action. All subsequent therapies and the prognosis depend on the identification of the causative agent and on information about substance-specific toxicity. Despite incomplete evidence the concept of harm reduction by decreased absorption of the toxicants and by shortening the course of illness is consistent with toxicokinetic-dynamic principles and is therefore still used by clinical toxicologists. All these treatment options have to be seen within the context of the prognosis and the time course of an individual case of poisoning. Treatment options of gastrointestinal decontamination are (in decreasing order of importance) single-dose activated charcoal, whole bowel irritation, and gastric lavage. Induced emesis by ipecac syrup is not practiced anymore. Enhanced elimination techniques are multiple-dose activated charcoal, urine alkalinization, and extracorporeal techniques such as hemodialysis and hemoperfusion. Enhanced elimination is only beneficial in toxicants with long half-life. Antidotes are directed against specific agents and therefore may be used only in a limited number of cases. The procurement of specific antidotes, often hardly available and not approved, is facilitated if the supply is organized in a transparent and standardized manner.

  15. Evaluation of oxime k203 as antidote in tabun poisoning.

    PubMed

    Kovarik, Zrinka; Vrdoljak, Ana Lucić; Berend, Suzana; Katalinić, Maja; Kuc, Kamil; Musilek, Kamil; Radić, Bozica

    2009-03-01

    We studied bispyridinium oxime K203 [(E)-1-(4-carbamoylpyridinium)-4-(4-hydroxyiminomethylpyridinium)-but-2-ene dibromide] with tabun-inhibited human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro, and its antidotal effect on tabun-poisoned mice and rats in vivo. We compared it with oximes K048 and TMB-4, which have proven the most efficient oxime antidotes in tabun poisoning by now. Tabun-inhibited AChE was completely reactivated by K203, with the overall reactivation rate constant of 1806 L mol(-1) min(-1). This means that K203 is a very potent reactivator of tabun-inhibited AChE. In addition, K203 reversibly inhibited AChE (Ki = 0.090 mmol L(-1)) and BChE (K(i) = 0.91 mmol L(-1)), and exhibited its protective effect against phosphorylation of AChE by tabun in vitro. In vivo, a quarter of the LD50 K203 dose insured survival of all mice after the application of as many as 8 LD50 doses of tabun, which is the highest dosage obtained compared to K048 and TMB-4. Moreover, K203 showed high therapeutic potency in tabun-poisoned rats, preserving cholinesterase activity in rat plasma up to 60 min after poisoning. This therapeutic improvement obtained by K203 in tabun-poisoning places this oxime in the spotlight for further development.

  16. Drugs of abuse: management of intoxication and antidotes.

    PubMed

    Montoya, Ivan D; McCann, David J

    2010-01-01

    Illicit drug intoxications are an increasing public health problem for which, in most cases, no antidotes are clinically available. The diagnosis and treatment of these intoxications requires a trained clinician with experience in recognizing the specific signs and symptoms of intoxications to individual drugs as well as polydrug intoxications, which are more the rule than the exception. To make the diagnosis, the clinical observation and a urine toxicology test are often enough. Evaluating the blood levels of drugs is frequently not practical because the tests can be expensive and results may be delayed and unavailable to guide the establishment of a treatment plan. Other laboratory tests may be useful depending on the drug or drugs ingested and the presence of other medical complications. The treatment should be provided in a quiet, safe and reassuring environment. Vital signs should be closely monitored. Changes in blood pressure, respiratory frequency and temperature should be promptly treated, particularly respiratory depression (in cases of opiate intoxication) or hyperthermia (in cases of cocaine or amphetamine intoxication). Intravenous fluids should be administered as soon as possible. Other psychiatric and medical complication should receive appropriate symptomatic treatment. Research on immunotherapies, including vaccines, monoclonal and catalytic antibodies, seems to be a promising approach that may yield specific antidotes for drugs of abuse, helping to ameliorate the morbidity and mortality associated with illicit drug intoxications.

  17. Evaluation of antidotes against the acute cardiovascular toxicity of propranolol.

    PubMed

    Strubelt, O

    1984-06-01

    Rats anesthetized with pentobarbital and ventilated artificially were intoxicated with 1 mg/kg X min propranolol i.v. After 30 min heart rate, mean arterial blood pressure and peripheral resistance had dropped by about 50% and cardiac output by about 25% and were stable for up to 120 min. Isoprenaline proved to be the best antidote for the treatment of propranolol intoxication antagonizing the bradycardia by 76% and the hypotension completely. The antagonistic activities of orciprenaline and prenalterol were lower than those of isoprenaline. Dopamine, adrenaline and noradrenaline antagonized propranolol-induced hypotension but did not considerably influence the bradycardia whereas dobutamine was nearly ineffective in both respects. Glucagon and aminophylline displayed some chronotropic activity without influencing propranolol-induced hypotension. Calcium chloride, on the other hand, produced a moderate elevation of blood pressure but only a small chronotropic activity, and atropine was inactive in both respects. Isoprenaline also restored the cardiac function of propranolol-poisoned rats if administered by infusion and, furthermore, increased the lethal dose of propranolol from 77 to 165 mg/kg. The strong antagonistic activity of isoprenaline against propranolol-induced cardiovascular depression was also confirmed by experiments in pigs. In conclusion, isoprenaline is the most active antidote for the treatment of propranolol intoxication in the rat though the administration of massive doses are required. The vasodilatory effect of isoprenaline can be overcome by the additional administration of a vasoconstricting agent like dopamine.

  18. Studies of antidote therapy for nisoldipine intoxication in experimental animals.

    PubMed

    Strubelt, O; Diederich, K W

    1990-07-01

    In anesthetized rats under artificial respiration, intravenous infusion of nisoldipine (0.1 mg/kg x min) caused significant decreases in blood pressure, heart rate, cardiac output and peripheral resistance. The animals died 54.7 +/- 11.1 min after initiation of the infusion. The electrocardiogram showed sinus bradycardia, increasing AV blockade and displacement of the pacemaker into the AV node or the bundle of His. Survival time under nisoldipine infusion increased more than two-fold with simultaneous infusion of calcium gluconate, isoprenaline (isoproterenol) or dopamine. Norepinephrine (noradrenaline) had no significant effect on survival time; the latter decreased to 19.4 +/- 1.6 min by plasma volume expansion with polygeline. All antidotes prolonging survival time also normalized the cardiac output diminished after nisoldipine. Electrocardiographic changes were antagonized only by isoprenaline. Suitable antidotes for intoxication or over-dosage of nisoldipine are calcium salts as well as beta-sympathomimetic drugs; sheer volume substitution and peripheral vascular constriction should not be resorted to.

  19. wtf genes are prolific dual poison-antidote meiotic drivers

    PubMed Central

    Nuckolls, Nicole L; Bravo Núñez, María Angélica; Eickbush, Michael T; Young, Janet M; Lange, Jeffrey J; Yu, Jonathan S; Smith, Gerald R; Jaspersen, Sue L; Malik, Harmit S; Zanders, Sarah E

    2017-01-01

    Meiotic drivers are selfish genes that bias their transmission into gametes, defying Mendelian inheritance. Despite the significant impact of these genomic parasites on evolution and infertility, few meiotic drive loci have been identified or mechanistically characterized. Here, we demonstrate a complex landscape of meiotic drive genes on chromosome 3 of the fission yeasts Schizosaccharomyces kambucha and S. pombe. We identify S. kambucha wtf4 as one of these genes that acts to kill gametes (known as spores in yeast) that do not inherit the gene from heterozygotes. wtf4 utilizes dual, overlapping transcripts to encode both a gamete-killing poison and an antidote to the poison. To enact drive, all gametes are poisoned, whereas only those that inherit wtf4 are rescued by the antidote. Our work suggests that the wtf multigene family proliferated due to meiotic drive and highlights the power of selfish genes to shape genomes, even while imposing tremendous costs to fertility. DOI: http://dx.doi.org/10.7554/eLife.26033.001 PMID:28631612

  20. Neuroprotective efficacy of pharmacological pretreatment and antidotal treatment in tabun-poisoned rats.

    PubMed

    Krejcová, G; Kassa, J

    2003-03-14

    To study the influence of pharmacological pretreatment (PANPAL) and antidotal treatment (obidoxime plus atropine) on tabun-induced neurotoxicity, male albino rats were poisoned with a lethal dose of tabun (280 microg/kg i.m.; 100% of LD(50) value) and observed at 24 h and 7 days following tabun challenge. The neurotoxicity of tabun was evaluated using a functional observational battery (FOB) and an automatic measurement of motor activity. Pharmacological pretreatment as well as antidotal treatment were able to eliminate most of tabun-induced neurotoxic effects observed at 24 h following tabun poisoning. However, there was not significant difference between the efficacy of PANPAL and antidotal treatment to eliminate tabun-induced neurotoxicity in rats. The combination of PANPAL pretreatment and antidotal treatment seems to be slightly more effective in the elimination of tabun-induced neurotoxicity in rats at 24 h following tabun challenge in comparison with the administration of PANPAL pretreatment or antidotal treatment alone. At 7 days following tabun poisoning, very few neurotoxic signs in tabun-poisoned rats were observed regardless of administration of pharmacological pretreatment or antidotal treatment. Thus, our findings confirm that the combination of pharmacological pretreatment and antidotal treatment is not only able to protect the experimental animals from the lethal effects of tabun but also to eliminate most of tabun-induced signs of neurotoxicity in tabun-poisoned rats.

  1. A novel paradigm for assessing efficacies of potential antidotes against neurotoxins in mice.

    PubMed

    Crankshaw, Daune L; Goon, David J W; Briggs, Jacquie E; DeLong, David; Kuskowski, Michael; Patterson, Steven E; Nagasawa, Herbert T

    2007-12-10

    Historically, antidotal potencies of cyanide antagonists were measured as increases in the experimental LD(50) for cyanide elicited by the antidotes. This required the use of high doses of cyanide following pre-treatment with the putative antidote. Since IACUC guidelines at our institutions strongly discourage LD(50) determinations: we developed a new test paradigm that allowed for maximal survival of cyanide-treated animals with greatly reduced numbers of animals. Symptoms of cyanide toxicity include disruption of neuromuscular coordination, i.e., the righting reflex. Therefore, to establish a dose-response curve, the times required for recovery of this righting reflex with increasing doses of cyanide were measured. A cyanide dose that disrupted this righting reflex for approximately 1h with minimal deaths was then selected. Using this paradigm, the current cyanide antidotes, viz., nitrite plus thiosulfate and hydroxocobalamin, as well as some potential cyanide antidotes that we developed, were evaluated pre- and post-cyanide. This allowed, for the first time, the assessment of the post-cyanide effectiveness of the current antidotes against cyanide poisoning in a live animal. In addition, some prototype compounds were found to exhibit antidotal efficacy not only when injected i.p. following cyanide, but also when administered orally 30 min before cyanide. Pre-cyanide oral efficacy suggests that such compounds have the potential of being administered prophylactically before exposure to cyanide. This new test paradigm was found to be a powerful tool for assessing the efficacies of some novel antidotes against cyanide and should be equally applicable for evaluating putative antidotes for other neurotoxins.

  2. NKG2D ligands as therapeutic targets

    PubMed Central

    Spear, Paul; Wu, Ming-Ru; Sentman, Marie-Louise; Sentman, Charles L.

    2013-01-01

    The Natural Killer Group 2D (NKG2D) receptor plays an important role in protecting the host from infections and cancer. By recognizing ligands induced on infected or tumor cells, NKG2D modulates lymphocyte activation and promotes immunity to eliminate ligand-expressing cells. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present a useful target for immunotherapeutic approaches in cancer. Novel therapies targeting NKG2D ligands for the treatment of cancer have shown preclinical success and are poised to enter into clinical trials. In this review, the NKG2D receptor and its ligands are discussed in the context of cancer, infection, and autoimmunity. In addition, therapies targeting NKG2D ligands in cancer are also reviewed. PMID:23833565

  3. Lattice fermions

    NASA Technical Reports Server (NTRS)

    Wilczek, Frank

    1987-01-01

    A simple heuristic proof of the Nielsen-Ninomaya theorem is given. A method is proposed whereby the multiplication of fermion species on a lattice is reduced to the minimal doubling, in any dimension, with retention of appropriate chiral symmetries. Also, it is suggested that use of spatially thinned fermion fields is likely to be a useful and appropriate approximation in QCD - in any case, it is a self-checking one.

  4. Cold atoms in a rotating optical lattice

    NASA Astrophysics Data System (ADS)

    Foot, Christopher J.

    2009-05-01

    We have demonstrated a novel experimental arrangement which can rotate a two-dimensional optical lattice at frequencies up to several kilohertz. Our arrangement also allows the periodicity of the optical lattice to be varied dynamically, producing a 2D ``accordion lattice'' [1]. The angles of the laser beams are controlled by acousto-optic deflectors and this allows smooth changes with little heating of the trapped cold (rubidium) atoms. We have loaded a BEC into lattices with periodicities ranging from 1.8μm to 18μm, observing the collapse and revival of the diffraction orders of the condensate over a large range of lattice parameters as recently reported by a group in NIST [2]. We have also imaged atoms in situ in a 2D lattice over a range of lattice periodicities. Ultracold atoms in a rotating lattice can be used for the direct quantum simulation of strongly correlated systems under large effective magnetic fields, i.e. the Hamiltonian of the atoms in the rotating frame resembles that of a charged particle in a strong magnetic field. In the future, we plan to use this to investigate a range of phenomena such as the analogue of the fractional quantum Hall effect. [4pt] [1] R. A. Williams, J. D. Pillet, S. Al-Assam, B. Fletcher, M. Shotter, and C. J. Foot, ``Dynamic optical lattices: two-dimensional rotating and accordion lattices for ultracold atoms,'' Opt. Express 16, 16977-16983 (2008) [0pt] [2] J. H. Huckans, I. B. Spielman, B. Laburthe Tolra, W. D. Phillips, and J. V. Porto, Quantum and Classical Dynamics of a BEC in a Large-Period Optical Lattice, arXiv:0901.1386v1

  5. Very Fast Algorithms and Detection Performance of Multi-Channel and 2-D Parametric Adaptive Matched Filters for Airborne Radar

    DTIC Science & Technology

    2007-06-05

    tive to the AMF, [1] and [5] discovered that multi-channel and two-dimensional parametric estimation approaches could (1) reduce the computational...dimensional (2-D) parametric estimation using the 2-D least-squares-based lattice algorithm [4]. The specifics of the inverse are found in the next...non- parametric estimation techniques • Least square error (LSE) vs mean square error (MSE) • Primarily multi-channel (M-C) structures; also try 2-D

  6. Evaluation of processed borax as antidote for aconite poisoning.

    PubMed

    Sarkar, Prasanta Kumar; Prajapati, Pradeep K; Shukla, Vinay J; Ravishankar, Basavaiah

    2017-06-09

    Aconite root is very poisonous; causes cardiac arrhythmias, ventricular fibrillation and ventricular tachycardia. There is no specific antidote for aconite poisoning. In Ayurveda, dehydrated borax is mentioned for management of aconite poisoning. The investigation evaluated antidotal effect of processed borax against acute and sub-acute toxicity, cardiac toxicity and neuro-muscular toxicity caused by raw aconite. For acute protection Study, single dose of toxicant (35mg/kg) and test drug (22.5mg/kg and 112.5mg/kg) was administered orally, and then 24h survival of animals was observed. The schedule was continued for 30 days in sub-acute protection Study with daily doses of toxicant (6.25mg/kg), test drug (22.5mg/kg and 112.5mg/kg) and vehicle. Hematological and biochemical tests of blood and serum, histopathology of vital organs were carried out. The cardiac activity Study was continued for 30 days with daily doses of toxicant (6.25mg/kg), test drug (22.5mg/kg), processed borax solution (22.5mg/kg) and vehicle; ECG was taken after 1h of drug administration on 1(TB), 15th and on 30th day. For neuro-muscular activity Study, the leech dorsal muscle response to 2.5µg of acetylcholine followed by response of toxicant at 25µg and 50µg doses and then response of test drug at 25µg dose were recorded. Protection index indicates that treated borax gave protection to 50% rats exposed to the lethal dose of toxicant in acute protection Study. Most of the changes in hematological, biochemical parameters and histopathological Study induced by the toxicant in sub-acute protection Study were reversed significantly by the test drug treatment. The ventricular premature beat and ventricular tachyarrhythmia caused by the toxicant were reversed by the test drug indicate reversal of toxicant induced cardio-toxicity. The acetylcholine induced contractions in leech muscle were inhibited by toxicant and it was reversed by test drug treatment. The processed borax solution is found as an

  7. Anticholinergic drugs--functional antidotes for the treatment of tabun intoxication.

    PubMed

    Krejcová, Gabriela; Kassa, Jirí

    2004-01-01

    1. To study the influence of antidotes on tabun-induced neurotoxicity, the rats were injected intramuscularly with organophosphate tabun (LD50). The efficacy of choice antidotal treatment consisting of acetylcholinesterase reactivator obidoxime and one of four anticholinergic drugs (atropine, benactyzine, biperiden, scopolamine) was compared. 2. Testing of tabun-induced neurotoxicity progress was carried out using the method Functional observational battery. The experimental animals as well as controls were observed at 24 hours and 7 days following tabun or saline administration. 3. The results were compared to the condition of animals without anticholinergic drug (oxime alone) and control rats that received physiological solution instead of tabun and treatment. Antidotal treatment involving centrally acting anticholinergic drugs (benactyzine, biperiden, scopolamine) showed significantly higher neuroprotective efficacy compared to antidotal treatment containing atropine.

  8. Reprint of : Thermodynamic properties of a quantum Hall anti-dot interferometer

    NASA Astrophysics Data System (ADS)

    Levy Schreier, Sarah; Stern, Ady; Rosenow, Bernd; Halperin, Bertrand I.

    2016-08-01

    We study quantum Hall interferometers in which the interference loop encircles a quantum anti-dot. We base our study on thermodynamic considerations, which we believe reflect the essential aspects of interference transport phenomena. We find that similar to the more conventional Fabry-Perot quantum Hall interferometers, in which the interference loop forms a quantum dot, the anti-dot interferometer is affected by the electro-static Coulomb interaction between the edge modes defining the loop. We show that in the Aharonov-Bohm regime, in which effects of fractional statistics should be visible, is easier to access in interferometers based on anti-dots than in those based on dots. We discuss the relevance of our results to recent measurements on anti-dots interferometers.

  9. Quantitative 2D liquid-state NMR.

    PubMed

    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.

  10. Metallic and Magnetic 2D Materials Containing Planar Tetracoordinated C and N.

    PubMed

    Jimenez-Izal, Elisa; Saeys, Mark; Alexandrova, Anastassia N

    2016-08-26

    The top monolayers of surface carbides and nitrides of Co and Ni are predicted to yield new stable 2D materials upon exfoliation. These 2D phases are p4g clock reconstructed, and contain planar tetracoordinated C or N. The stability of these flat carbides and nitrides is high, and ab-initio molecular dynamics at a simulation temperature of 1800 K suggest that the materials are thermally stable at elevated temperatures. The materials owe their stability to local triple aromaticity (π-, σ-radial, and σ-peripheral) associated with binding of the main group element to the metal. All predicted 2D phases are conductors, and the two alloys of Co are also ferromagnetic - a property especially rare among 2D materials. The preparation of 2D carbides and nitrides is envisioned to be done through surface deposition and peeling, possibly on a metal with a larger lattice constant for reduced affinity.

  11. Completeness of the classical 2D Ising model and universal quantum computation.

    PubMed

    Van den Nest, M; Dür, W; Briegel, H J

    2008-03-21

    We prove that the 2D Ising model is complete in the sense that the partition function of any classical q-state spin model (on an arbitrary graph) can be expressed as a special instance of the partition function of a 2D Ising model with complex inhomogeneous couplings and external fields. In the case where the original model is an Ising or Potts-type model, we find that the corresponding 2D square lattice requires only polynomially more spins with respect to the original one, and we give a constructive method to map such models to the 2D Ising model. For more general models the overhead in system size may be exponential. The results are established by connecting classical spin models with measurement-based quantum computation and invoking the universality of the 2D cluster states.

  12. Idarucizumab as Antidote to Intracerebral Hemorrhage under Treatment with Dabigatran

    PubMed Central

    Held, Valentin; Eisele, Philipp; Eschenfelder, Christoph C.; Szabo, Kristina

    2016-01-01

    Background and Purpose Non-vitamin K anticoagulants (NOAC) such as dabigatran have become important therapeutic options for the prevention of stroke. Until recently, there were only nonspecific agents to reverse their anticoagulant effects in a case of emergency. Idarucizumab, an antibody fragment targeting dabigatran, is the first specific antidote for a NOAC to be approved, but real-world experience is limited. Methods We report two cases of patients on dabigatran with acute intracerebral hemorrhage who received idarucizumab. Results In both cases, idarucizumab promptly reversed the anticoagulant effect of dabigatran and there was no hematoma expansion in follow-up imaging. Conclusions In addition to clinical and preclinical studies, our cases add to the experience regarding the safety and efficacy of idarucizumab. They show that idarucizumab may be an important safety option for patients on dabigatran in emergency situations. PMID:27920714

  13. That's a Phat Antidote: Intravenous Fat Emulsions and Toxicological Emergencies.

    PubMed

    Schultz, Amy E; Lewis, Temeka; Reed, Brittany S; Weant, Kyle A; Justice, Stephanie Baker

    2015-01-01

    Health care providers in the emergency department (ED) frequently find themselves caring for patients who may have overdosed on a medication(s) or other toxic substance. These patients can prove to be a challenge, as providers must try to determine the substance(s) involved so that the appropriate treatment can be initiated. For those patients who are hemodynamically unstable upon presentation, it is important to note that supportive care is of the utmost importance, as there are few substances that have antidotes available. In these situations, lipid emulsion can be considered. This is especially true in the setting of the following toxicities: local anesthetics, β-blockers, calcium channel blockers, and the tricyclic antidepressants. Even though lipid emulsion may not be used that frequently in the ED, it is important to be aware of its role in the setting of toxicological emergencies, how it should be dosed and administered, and the necessary safety precautions.

  14. Antidotal Effects of Curcumin Against Agents-Induced Cardiovascular Toxicity.

    PubMed

    Farkhondeh, Tahereh; Samarghandian, Saeed

    Curcumin, the major phenolic compound in turmeric, shows preventive effects in various diseases. Curcumin is commonly found in rhizome of the Curcuma species and traditionally used in herbal medicine. Numeros studies has indicated that curcumin posses protective effects against toxic agents in various systems including cardiovascular. This study found that curcumin may be effective in cardiovascular diseases induced by toxic agents including Streptozotocin, Doxorubicin, Cyclosporin A, Methotrexate, Isoproterenol, Cadmium, Diesel exhaust particle, Nicotine, Hydrogen peroxide, and tert- Butyl hydroperoxide. However, due to the lake of information on human, further studies are needed to determine the efficacy of curcumin as an antidote agent. The present study aimed to critically review the recent literature data from that regarding the protective effects of curcumin against agents-induced cardiovascular toxicity.

  15. Intralipid emulsion treatment as an antidote in lipophilic drug intoxications.

    PubMed

    Eren Cevik, Sebnem; Tasyurek, Tanju; Guneysel, Ozlem

    2014-09-01

    Intravenous lipid emulsion (ILE) is a lifesaving treatment of lipophilic drug intoxications. Not only does ILE have demonstrable efficacy as an antidote to local anesthetic toxicity, it is also effective in lipophilic drug intoxications. Our case series involved 10 patients with ingestion of different types of lipophilic drugs. Intravenous lipid emulsion treatment improved Glasgow Coma Scale or blood pressure and pulse rate or both according to the drug type. Complications were observed in 2 patients (minimal change pancreatitis and probable ILE treatment-related fat infiltration in lungs). In our case series, ILE was used for different lipophilic drug intoxications to improve cardiovascular and neurologic symptoms. According to the results, it was found that ILE treatment is a lifesaving agent in lipophilic drug intoxications and it can be used in unconscious patients who have cardiac and/or neurologic symptoms but no history of a specific drug ingestion.

  16. Hydrogen sulfide poisoning: an antidotal role for sodium nitrite?

    PubMed

    Hall, A H; Rumack, B H

    1997-06-01

    In 2 separate incidents, 6 patients were poisoned with hydrogen sulfide (H2S) in sewer gas. In the first incident, mixing acid- and sodium hydroxide-based drain cleaners in a confined space resulted in 4 poisonings and 2 deaths. Three would-be rescuers were seriously poisoned and 1 died. Two survivors had neurological sequelae. Sodium nitrite appeared to have some clinical efficacy in 1 case. The second incident involved 2 patients working on a pump in a sewage pond. A patient lying on a raft close to the pond surface was seriously poisoned; sodium nitrite was clinically efficacious and this patient survived without developing neurological sequelae. Sodium nitrite deserves further clinical study as a potential H2S antidote.

  17. Antidotal action of sodium nitrite and sodium thiosulfate against cyanide poisoning. (Reannouncement with new availability information)

    SciTech Connect

    Baskin, S.I.; Horowitz, A.M.; Nealley, E.W.

    1992-04-01

    The combination of sodium thiosulfate and sodium nitrite has been used in the United States since the 1930s as the primary antidote for cyanide intoxication. Although this combination was shown to exhibit much greater efficacy than either ingredient alone, the two compounds could not be used prophylactically because each exhibits a number of side effects. This review discusses the pharmacodynamics, pharmacokinetics, and toxicology of the individual agents, and their combination....Cyanide, Blood agent, Chemical warfare agents, Antidotes, Sodium nitrite, Sodium thiosulfate.

  18. Specific antidotes in development for reversal of novel anticoagulants: a review.

    PubMed

    Gomez-Outes, Antonio; Suarez-Gea, M L; Lecumberri, Ramon; Terleira-Fernandez, Ana I; Vargas-Castrillon, Emilio

    2014-01-01

    In the last decade, several direct oral anticoagulants (DOAC; dabigatran, rivaroxaban, apixaban, edoxaban) have been marketed for prophylaxis and/or treatment of thromboembolism without having specific antidotes available for their reversal. Current management of bleeding associated to DOAC includes the removal of all antithrombotic medications and supportive care. Non-specific procoagulant agents (prothrombin complex concentrates and activated factor VIIa) have been used in case of serious bleeding. Currently, some specific antidotes for the DOAC are under development. Idarucizumab (BI 655075; Boehringer Ingelheim) is a fragment of an antibody (Fab), which is a specific antidote to the oral direct thrombin inhibitor dabigatran. Andexanet alfa (r-Antidote, PRT064445; Portola Pharmaceuticals) is a truncated form of enzymatically inactive factor Xa, which binds and reverses the anticoagulant action of the factor Xa inhibitors (e.g.: rivaroxaban, apixaban and edoxaban). Aripazine (PER-977, ciraparantag; Perosphere Inc.) is a synthetic small molecule (~500 Da) that reverses oral dabigatran, apixaban, rivaroxaban, as well as subcutaneous fondaparinux and LMWH in vivo. These antidotes could provide an alternative for management of life-threatening bleeding events occurring with the above-mentioned anticoagulants. In addition, the specific antidote anivamersen (RB007; Regado Biosciences Inc.) is an RNA aptamer in clinical development to reverse the anticoagulant effect of the parenteral factor IXa inhibitor pegnivacogin, which is also in development. This anticoagulant-antidote pair may provide an alternative in situations in which a fast onset and offset of anticoagulation is needed, like in patients undergoing cardiac surgery with extracorporeal circulation, as an alternative to the heparin/protamine pair. This patent review includes a description of the pharmacological characteristics of the novel specific antidotes, the available results from completed non

  19. Molecular Modeling in Drug Design for the Development of Organophosphorus Antidotes/Prophylactics.

    DTIC Science & Technology

    1986-06-01

    R176 274 MOLECULAR MODELING IN DRUG DESIGN FOR THE DEVELOPMENT 1/1OF ORGANOPI4OSPHORUS (U) AMERICA CYANAMID CO PEARL RIVER NY LEDERLE LAOS DIV R...MOLECULAR MODELING IN DRUG DESIGN FOR THE DEVELO ’"ENT OF ORGANOPHOSPHORUS ANTIDOTES/PROPHYLACTICS Final Report R. Venkataraghavan, Ph.D. June 1, 1986 I...Security Classification) (U) .Molecular Modeling in Drug Design for the Development of Organophosphorus Antidotes/Prophylactics 12 PERSONAL AUTHOR(S) R

  20. Cyanide Antidotes for Mass Casualties: Comparison of Intramuscular Injector by Autoinjector, Intraosseous Injection, and Inhalational Delivery

    DTIC Science & Technology

    2014-10-01

    Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Current antidotes for cyanide poisoning must be administered by...dimethyltrisulfide, and sulfanegen. 15. SUBJECT TERMS Cyanide Poisoning ; Intramuscular Injection; Intraosseous Injection; Inhalational Delivery 16...7 Appendices…………………………………………………………………………………. 8 4 INTRODUCTION Cyanide is a rapidly acting poison , and, thus, antidotes must be

  1. Temperature-dependent nonlinear Hall effect in macroscopic Si-MOS antidot array

    NASA Astrophysics Data System (ADS)

    Kuntsevich, A. Yu.; Shupletsov, A. V.; Nunuparov, M. S.

    2016-05-01

    By measuring magnetoresistance and the Hall effect in a classically moderate perpendicular magnetic field in a Si-MOSFET-type macroscopic antidot array, we found a nonlinear with field, temperature- and density-dependent Hall resistivity. We argue that this nonlinearity originates from low mobility shells of the antidots with a strong temperature dependence of the resistivity and suggest a qualitative explanation of the phenomenon.

  2. Mirror effects and optical meta-surfaces in 2d atomic arrays

    NASA Astrophysics Data System (ADS)

    Shahmoon, Ephraim; Wild, Dominik; Lukin, Mikhail; Yelin, Susanne

    2016-05-01

    Strong optical response of natural and artificial (meta-) materials typically relies on the fact that the lattice constant that separates their constituent particles (atoms or electromagnetic resonators, respectively) is much smaller than the optical wavelength. Here we consider a single layer of a 2d atom array with a lattice constant on the order of an optical wavelength, which can be thought of as a highly dilute 2d metamaterial (meta-surface). Our theoretical analysis shows how strong scattering of resonant incoming light off the array can be controlled by choosing its lattice constant, e.g. allowing the array to operate as a perfect mirror or a retro-reflector for most incident angles of the incoming light. We discuss the prospects for quantum metasurfaces, i.e. the ability to shape the output quantum state of light by controlling the atomic states, and the possible generality of our results as a universal wave phenomena.

  3. Crystal structure of the MazE/MazF complex: molecular bases of antidote-toxin recognition.

    PubMed

    Kamada, Katsuhiko; Hanaoka, Fumio; Burley, Stephen K

    2003-04-01

    A structure of the Escherichia coli chromosomal MazE/MazF addiction module has been determined at 1.7 A resolution. Addiction modules consist of stable toxin and unstable antidote proteins that govern bacterial cell death. MazE (antidote) and MazF (toxin) form a linear heterohexamer composed of alternating toxin and antidote homodimers (MazF(2)-MazE(2)-MazF(2)). The MazE homodimer contains a beta barrel from which two extended C termini project, making interactions with flanking MazF homodimers that resemble the plasmid-encoded toxins CcdB and Kid. The MazE/MazF heterohexamer structure documents that the mechanism of antidote-toxin recognition is common to both chromosomal and plasmid-borne addiction modules, and provides general molecular insights into toxin function, antidote degradation in the absence of toxin, and promoter DNA binding by antidote/toxin complexes.

  4. Magnetic characteristics of CoPd and FePd antidot arrays on nanoperforated Al2O3 templates

    NASA Astrophysics Data System (ADS)

    Maximenko, A.; Fedotova, J.; Marszałek, M.; Zarzycki, A.; Zabila, Y.

    2016-02-01

    Hard magnetic antidot arrays show promising results in context of designing of percolated perpendicular media. In this work the technology of magnetic FePd and CoPd antidot arrays fabrication is presented and correlation between surface morphology, structure and magnetic properties is discussed. CoPd and FePd antidot arrays were fabricated by deposition of Co/Pd and Fe/Pd multilayers (MLs) on porous anodic aluminum oxide templates with bowl-shape cell structure with inclined intercellular regions. FePd ordered L10 structure was obtained by successive vacuum annealing at elevated temperatures (530 °C) and confirmed by XRD analysis. Systematic analysis of magnetization curves evidenced perpendicular magnetic anisotropy of CoPd antidot arrays, while FePd antidot arrays revealed isotropic magnetic anisotropy with increased out-of-plane magnetic contribution. MFM images of antidots showed more complicated contrast, with alternating magnetic dots oriented parallel and antiparallel to tip magnetization moment.

  5. Staring 2-D hadamard transform spectral imager

    DOEpatents

    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.

  6. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  7. [Effect of antidotes on the rate of absorption of 2,4-dinitrophenol from the digestive tract into the blood].

    PubMed

    Sen'chuk, V; Adamska, T

    1977-01-01

    An investigation of the rate of the 2,4-dinitrophenol absorption from the digestive tract into the blood with the use of an antidote and its components (activated charcoal, tannin, magnesium oxide), stach water and paraffin oil demonstrated the activated charcoal and magnesium oxide to be the best antidotes among the ones studied. The antidote exerts a somewhat less marked, but still quite a strong action.

  8. A 2D Substitutional Solid Solution through Hydrogen Bonding of Molecular Building Blocks.

    PubMed

    MacLeod, Jennifer M; Lipton-Duffin, Josh; Fu, Chaoying; Taerum, Tyler; Perepichka, Dmitrii F; Rosei, Federico

    2017-09-26

    Two-dimensional (2D) molecular self-assembly allows for the formation of well-defined supramolecular layers with tailored geometrical, compositional, and chemical properties. To date, random intermixing and entropic effects in these systems have largely been associated with crystalline disorder and glassy phases. Here we describe a 2D crystalline self-assembled molecular system that exhibits random incorporation of substitutional molecules. The lattice is formed from a mixture of trimesic acid (TMA) and terthienobenzenetricarboxylic acid (TTBTA), C3-symmetric hydrogen-bonding units of very different sizes (0.79 and 1.16 nm, respectively), at the solution-highly oriented pyrolitic graphite (HOPG) interface. Remarkably, the TTBTA substitutes into the TMA lattice at a fixed stoichiometry near 12%. The resulting lattice constant is consistent with Vegard's law prediction for an alloy with a composition TMA0.88TTBTA0.12, and the substrate orientation of the lattice is defined by an epitaxial relation with the HOPG substrate. The Gibbs free energy for the TMA/TTBTA lattice was elucidated by considering the entropy of intermixing, via Monte Carlo simulations of multiplicity of the substitutional lattices, and the enthalpy of intermixing, via density functional theory calculations. The latter show that both the bond enthalpy of the H-bonded lattice and the adsorption enthalpy of the molecule/substrate interactions play important roles. This work provides insight into the manifestation of entropy in a molecular crystal constrained by both epitaxy and intermolecular interactions and demonstrates that a randomly intermixed yet crystalline 2D solid can be formed through hydrogen bonding of molecular building blocks of very different size.

  9. Kind and estimated stocking amount of antidotes for initial treatment for acute poisoning at emergency medical centers in Korea.

    PubMed

    Sohn, Chang Hwan; Ryoo, Seung Mok; Lim, Kyoung Soo; Kim, Won; Lim, Hoon; Oh, Bum Jin

    2014-11-01

    Antidotes for toxicological emergencies can be life-saving. However, there is no nationwide estimation of the antidotes stocking amount in Korea. This study tried to estimate the quantities of stocking antidotes at emergency department (ED). An expert panel of clinical toxicologists made a list of 18 emergency antidotes. The quantity was estimated by comparing the antidote utilization frequency in a multicenter epidemiological study and the nation-wide EDs' data of National Emergency Department Information System (NEDIS). In an epidemiological study of 11 nationwide EDs from January 2009 to December 2010, only 92 (1.9%) patients had been administered emergency antidotes except activated charcoal among 4,870 cases of acute adult poisoning patients. Comparing with NEDIS data, about 1,400,000 patients visited the 124 EDs nationwide due to acute poisoning and about 103,348 adult doses of the 18 emergency antidotes may be required considering poisoning severity score. Of these, 13,224 (1.9%) adult doses of emergency antidotes (575 of atropine, 144 of calcium gluconate or other calcium salts, 2,587 of flumazenil, 3,450 of N-acetylcysteine, 5,893 of pralidoxime, 287 of hydroxocobalamin, 144 of sodium nitrite, and 144 of sodium thiosulfate) would be needed for maintaining the present level of initial treatment with emergency antidotes at EDs in Korea.

  10. Experimental realization and characterization of an electronic Lieb lattice

    NASA Astrophysics Data System (ADS)

    Slot, Marlou R.; Gardenier, Thomas S.; Jacobse, Peter H.; van Miert, Guido C. P.; Kempkes, Sander N.; Zevenhuizen, Stephan J. M.; Smith, Cristiane Morais; Vanmaekelbergh, Daniel; Swart, Ingmar

    2017-07-01

    Geometry, whether on the atomic or nanoscale, is a key factor for the electronic band structure of materials. Some specific geometries give rise to novel and potentially useful electronic bands. For example, a honeycomb lattice leads to Dirac-type bands where the charge carriers behave as massless particles. Theoretical predictions are triggering the exploration of novel two-dimensional (2D) geometries, such as graphynes and the kagomé and Lieb lattices. The Lieb lattice is the 2D analogue of the 3D lattice exhibited by perovskites; it is a square-depleted lattice, which is characterized by a band structure featuring Dirac cones intersected by a flat band. Whereas photonic and cold-atom Lieb lattices have been demonstrated, an electronic equivalent in 2D is difficult to realize in an existing material. Here, we report an electronic Lieb lattice formed by the surface state electrons of Cu(111) confined by an array of carbon monoxide molecules positioned with a scanning tunnelling microscope. Using scanning tunnelling microscopy, spectroscopy and wavefunction mapping, we confirm the predicted characteristic electronic structure of the Lieb lattice. The experimental findings are corroborated by muffin-tin and tight-binding calculations. At higher energies, second-order electronic patterns are observed, which are equivalent to a super-Lieb lattice.

  11. Unusual dimensionality effects and surface charge density in 2D Mg(OH)2

    PubMed Central

    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

  12. Unusual dimensionality effects and surface charge density in 2D Mg(OH)2.

    PubMed

    Suslu, Aslihan; Wu, Kedi; Sahin, Hasan; Chen, Bin; Yang, Sijie; Cai, Hui; Aoki, Toshihiro; Horzum, Seyda; Kang, Jun; Peeters, Francois M; Tongay, Sefaattin

    2016-02-05

    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.

  13. Strain-induced Fermi contour anisotropy of GaAs (311)A 2D holes

    NASA Astrophysics Data System (ADS)

    Shabani, Javad; Shayegan, Mansour; Winkler, Roland

    2008-03-01

    There is considerable current interest in electronic properties of two-dimensional (2D) carriers whose energy bands are spin-split at finite values of in-plane wave vector, thanks to the spin-orbit interaction and the lack of inversion symmetry. We report experimental and theoretical results revealing that the spin-subband Fermi contours of the heavy and light heavy-holes (HHh and HHl) can be tuned in high mobility GaAs (311)A 2D hole systems via the application of symmetry-breaking in-plane strain. Our calculations show that the HHl spin-subband Fermi contour is circular but the HHh spin-subband Fermi contour is distorted. Experimentally, we probe the Fermi contour anisotropy by measuring the magneto-resistance commensurability peaks induced by square arrays of antidots. When the spin splitting is sufficiently large, the magneto-resistance trace exhibits two peaks, providing clear evidence for spin-resolved ballistic transport. The experimental results are in good agreement with the calculations, and confirm that the majority spin-subband (HHh) has a severely distorted Fermi contour whose anisotropy can be tuned with strain while Fermi contour of the minority spin-subband (HHl) remains nearly isotropic.

  14. Benzylpenicillin, acetylcysteine and silibinin as antidotes in human hepatocytes intoxicated with alpha-amanitin.

    PubMed

    Magdalan, Jan; Ostrowska, Alina; Piotrowska, Aleksandra; Gomułkiewicz, Agnieszka; Podhorska-Okołów, Marzena; Patrzałek, Dariusz; Szelag, Adam; Dziegiel, Piotr

    2010-07-01

    Fatalities due to mushroom poisonings are increasing worldwide, with high mortality rate resulting from ingestion of amanitin-producing species. Intoxications caused by amanitin-containing mushrooms represent an unresolved problem in clinical toxicology since no specific and fully efficient antidote is available. The objective of this study was a comparative evaluation of benzylpenicillin (BPCN), acetylcysteine (ACC) and silibinin (SIL) as an antidotes in human hepatocytes intoxicated with alpha-amanitin (alpha-AMA). All experiments were performed on cultured human hepatocytes. Cytotoxicity evaluation of cultured cells using MTT assay and measurement of lactate dehydrogenase (LDH) activity was performed at 12, 24 and 48h of exposure to alpha-AMA and/or antidotes. The significant decline of cell viability and significant increase of LDH activity were observed in all experimental hepatocyte cultures after 12, 24 and 36h exposure to alpha-AMA at concentration 2microM. Exposure of the cells to alpha-AMA resulted also in significant reduction of cell spreading and attachment. However, addition of tested antidotes to experimental cultures significantly stimulated cell proliferation and attachment. In cell cultures exposed simultaneously to alpha-AMA and tested antidotes cytotoxic parameters (MTT and LDH) were not significantly different from control incidences. The cytoprotective effect of all antidotes was not dose-related, which reflects a high efficacy of all these substances. Administration of studied antidotes was not associated with any adverse effects in hepatocytes. The administration of ACC, BPCN or SIL to human hepatocyte cultures showed a similar strong protective effect against cell damage in alpha-AMA toxicity.

  15. Intrinsic limitations of spin transport in 2D membranes

    NASA Astrophysics Data System (ADS)

    Song, Yang

    2014-03-01

    Two dimensional membranes have become the playground for both theorists and experimentalists due to their unique intrinsic properties emerged from simple lattice structures. They are the new focus of spintronic applications. Therefore, it is important that we have a clear view of the relaxation processes in spin transport, limited by their intrinsic and symmetry structures. In this talk, we present our findings by systematically applying group theory to the coupling of phonons and transport carriers in spin-dependent scattering. Scattering by phonon is amplified in 2D membranes due to its unique and populous flexural mode. Opposite spin coupling by one flexural phonon is allowed by symmetry, unlike the momentum scattering by higher-order two flexural phonons. Furthermore, we specifically discuss the ultrafast electron spin relaxation in single-layer transition metal dichalcogenides (SL-TMDs). The additional factor stems from the decoupling of tiny conduction band spin splitting and the large spin scattering constant. The former results from conduction band orbital orientation, while the latter comes from inter-band coupling and reflects the atomic SOC strength. We will present that the essential use of group theory (invariant quantities) elucidates various spin-dependent selection rules of electron/hole-phonon interaction, within and between all relevant band-valley edges. Multiple potential applications of the derived results can be explored in transport problems, such as the strain effects, spin Gunn effect, hot exciton dynamics, and the scattering angle and spin anisotropy dependence. We compare different 2D membranes (graphene, SL-TMD, silicene and germanene) from general consideration of the lattice and band-edge symmetries. This work is supported by NRI-NSF, NSF, and DTRA Contracts No. DMR-1124601, No. ECCS-1231570, and No. HDTRA1-13-1-0013, respectively.

  16. Matrix models of 2d gravity

    SciTech Connect

    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.

  17. Matrix models of 2d gravity

    SciTech Connect

    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.

  18. Brittle damage models in DYNA2D

    SciTech Connect

    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.

  19. 2D/3D switchable displays

    NASA Astrophysics Data System (ADS)

    Dekker, T.; de Zwart, S. T.; Willemsen, O. H.; Hiddink, M. G. H.; IJzerman, W. L.

    2006-02-01

    A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. We will discuss 3D image quality, with the focus on display uniformity. We show that slanting the lenticulars in combination with a good lens design can minimize non-uniformities in our 20" 2D/3D monitors. Furthermore, we introduce fractional viewing systems as a very robust concept to further improve uniformity in the case slanting the lenticulars and optimizing the lens design are not sufficient. We will discuss measurements and numerical simulations of the key optical characteristics of this display. Finally, we discuss 2D image quality, the switching characteristics and the residual lens effect.

  20. 2-d Finite Element Code Postprocessor

    SciTech Connect

    Sanford, L. A.; Hallquist, J. O.

    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 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.

  1. Chemical Approaches to 2D Materials.

    PubMed

    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.

  2. Vorticity Generation by Rough Walls in 2D Decaying Turbulence

    NASA Astrophysics Data System (ADS)

    Tóth, Gábor; Jánosi, Imre M.

    2015-12-01

    In this work we present Lattice Boltzmann simulations of a decaying vortex array in a 2D rectangular domain, which is bounded by a random rough wall from one side. In order to separate the effects of the collisions with the rough wall, the opposite (smooth) rigid wall is placed at a larger distance from the center of the vortex array. Periodic boundary condition is imposed in the perpendicular direction. Well defined random roughness is generated by the widely studied Wolf-Villain surface growth algorithm. The main finding is that collisions with a rough wall generate excess vorticity compared with a smooth boundary, while the kinetic energy decreases monotonously. A proper measure is the integrated excess enstrophy, which exhibits an apparent maximum at an "optimal" roughness range. Numerical values of the excess enstrophy are very sensitive to a particular configuration (wall shape and vortex lattice randomization), however the "optimal" roughness exhibits surface features of similar characteristic sizes than that of the decaying vortices.

  3. A design principle of polymers processable into 2D homeotropic order

    PubMed Central

    Chen, Zhen; Chan, Yi-Tsu; Miyajima, Daigo; Kajitani, Takashi; Kosaka, Atsuko; Fukushima, Takanori; Lobez, Jose M.; Aida, Takuzo

    2016-01-01

    How to orient polymers homeotropically in thin films has been a long-standing issue in polymer science because polymers intrinsically prefer to lie down. Here we provide a design principle for polymers that are processable into a 2D homeotropic order. The key to this achievement was a recognition that cylindrical polymers can be designed to possess oppositely directed local dipoles in their cross-section, which possibly force polymers to tightly connect bilaterally, affording a 2D rectangular assembly. With a physical assistance of the surface grooves on Teflon sheets that sandwich polymer samples, homeotropic ordering is likely nucleated and gradually propagates upon hot-pressing towards the interior of the film. Consequently, the 2D rectangular lattice is constructed such that its b axis (side chains) aligns along the surface grooves, while its c axis (polymer backbone) aligns homeotropically on a Teflon sheet. This finding paves the way to molecularly engineered 2D polymers with anomalous functions. PMID:27897189

  4. A design principle of polymers processable into 2D homeotropic order

    NASA Astrophysics Data System (ADS)

    Chen, Zhen; Chan, Yi-Tsu; Miyajima, Daigo; Kajitani, Takashi; Kosaka, Atsuko; Fukushima, Takanori; Lobez, Jose M.; Aida, Takuzo

    2016-11-01

    How to orient polymers homeotropically in thin films has been a long-standing issue in polymer science because polymers intrinsically prefer to lie down. Here we provide a design principle for polymers that are processable into a 2D homeotropic order. The key to this achievement was a recognition that cylindrical polymers can be designed to possess oppositely directed local dipoles in their cross-section, which possibly force polymers to tightly connect bilaterally, affording a 2D rectangular assembly. With a physical assistance of the surface grooves on Teflon sheets that sandwich polymer samples, homeotropic ordering is likely nucleated and gradually propagates upon hot-pressing towards the interior of the film. Consequently, the 2D rectangular lattice is constructed such that its b axis (side chains) aligns along the surface grooves, while its c axis (polymer backbone) aligns homeotropically on a Teflon sheet. This finding paves the way to molecularly engineered 2D polymers with anomalous functions.

  5. Two-dimensional lattice liquid models

    NASA Astrophysics Data System (ADS)

    Ishimoto, Yukitaka; Murashima, Takahiro; Taniguchi, Takashi; Yamamoto, Ryoichi

    2012-09-01

    A family of models of liquid on a two-dimensional lattice (2D lattice liquid models) have been proposed as primitive models of soft-material membrane. As a first step, we have formulated them as single-component, single-layered, classical particle systems on a two-dimensional surface with no explicit viscosity. Among the family of the models, we have shown and constructed two stochastic models, a vicious walk model and a flow model, on an isotropic regular lattice and on some honeycomb lattices of various sizes. In both cases, the dynamics is governed by the nature of the frustration of the particle movements. By simulations, we have found the approximate functional form of the frustration probability and peculiar anomalous diffusions in their time-averaged mean-square displacements in the flow model. The relations to other existing statistical models and possible extensions of the models are also discussed.

  6. Beam-Plasma Interaction and Instabilities in a 2D Yukawa Plasma

    NASA Astrophysics Data System (ADS)

    Kyrkos, S.; Kalman, G.; Rosenberg, M.

    2008-11-01

    In a complex plasma, penetrating charged particle beams may lead to beam-plasma instabilities. When either the plasma, the beam, or both, are strongly interacting [1], the features of the instability are different from those in a weakly coupled plasma. We consider the case when a 2D dusty plasma forms a lattice, and the beam is moving in the lattice plane. Both the grains and the beam particles interact through a Yukawa potential; the beam particles are weakly coupled to each other and to the lattice. The system develops both a longitudinal and a transverse instability. Based on the phonon spectrum of a 2D hexagonal Yukawa lattice [2], we determine and compare the transverse and longitudinal growth rates. As a function of the wavenumber, the growth rates exhibit remarkable gaps, where no instability is excited. The gap locations are governed by the ratio of the lattice and the beam plasma frequencies. The behavior of the growth rates also depends on the direction of the beam and on the relationship between the beam speed and the longitudinal and transverse sound speeds. [1] GJ Kalman, M Rosenberg, JPA 36, 5963 (2003). [2] T Sullivan, GJ Kalman, S Kyrkos, P Bakshi, M Rosenberg, Z Donko, JPA 39, 4607 (2006).

  7. An in vivo zebrafish screen identifies organophosphate antidotes with diverse mechanisms of action.

    PubMed

    Jin, Shan; Sarkar, Kumar S; Jin, Youngnam N; Liu, Yan; Kokel, David; Van Ham, Tjakko J; Roberts, Lee D; Gerszten, Robert E; Macrae, Calum A; Peterson, Randall T

    2013-01-01

    Organophosphates are a class of highly toxic chemicals that includes many pesticides and chemical weapons. Exposure to organophosphates, either through accidents or acts of terrorism, poses a significant risk to human health and safety. Existing antidotes, in use for over 50 years, have modest efficacy and undesirable toxicities. Therefore, discovering new organophosphate antidotes is a high priority. Early life stage zebrafish exposed to organophosphates exhibit several phenotypes that parallel the human response to organophosphates, including behavioral deficits, paralysis, and eventual death. Here, we have developed a high-throughput zebrafish screen in a 96-well plate format to find new antidotes that counteract organophosphate-induced lethality. In a pilot screen of 1200 known drugs, we identified 16 compounds that suppress organophosphate toxicity in zebrafish. Several in vitro assays coupled with liquid chromatography/tandem mass spectrometry-based metabolite profiling enabled determination of mechanisms of action for several of the antidotes, including reversible acetylcholinesterase inhibition, cholinergic receptor antagonism, and inhibition of bioactivation. Therefore, the in vivo screen is capable of discovering organophosphate antidotes that intervene in distinct pathways. These findings suggest that zebrafish screens might be a broadly applicable approach for discovering compounds that counteract the toxic effects of accidental or malicious poisonous exposures.

  8. Recent advances in the development of specific antidotes for target-specific oral anticoagulants.

    PubMed

    Mo, Yoonsun; Yam, Felix K

    2015-02-01

    Warfarin, a vitamin K antagonist, has been the only orally available anticoagulant for > 60 years. During the past decade, the U.S. Food and Drug Administration has approved several target-specific oral anticoagulants (TSOACs) for the prophylaxis and treatment of arterial and venous thromboembolism and stroke prevention in patients with nonvalvular atrial fibrillation. These new agents have several advantages over warfarin including more predictable pharmacokinetics and pharmacodynamics, fewer food and drug interactions, and lack of need for routine coagulation monitoring. However, unlike warfarin, currently no antidotes are available to reverse the anticoagulant effect of TSOACs. Specific antidotes for TSOACs may not be needed in most situations due to their short half-life, yet the absence of antidotes for these agents is a concern, especially in emergent situations such as life-threatening major bleeding or nonelective major surgery. Several specific antidotes for TSOACs including idarucizumab, andexanet alfa, and aripazine have been developed and have shown promise in early clinical trials evaluating their efficacy and safety. In this narrative review, the progress made in developing specific antidotes for TSOACs is summarized based on the latest available preclinical and clinical data.

  9. An In Vivo Zebrafish Screen Identifies Organophosphate Antidotes with Diverse Mechanisms of Action

    PubMed Central

    Jin, Shan; Sarkar, Kumar S.; Jin, Youngnam N.; Liu, Yan; Kokel, David; Van Ham, Tjakko J.; Roberts, Lee D.; Gerszten, Robert E.; MacRae, Calum A.; Peterson, Randall T.

    2014-01-01

    Organophosphates are a class of highly toxic chemicals that includes many pesticides and chemical weapons. Exposure to organophosphates, either through accidents or acts of terrorism, poses a significant risk to human health and safety. Existing antidotes, in use for over 50 years, have modest efficacy and undesirable toxicities. Therefore, discovering new organophosphate antidotes is a high priority. Early life stage zebrafish exposed to organophosphates exhibit several phenotypes that parallel the human response to organophosphates, including behavioral deficits, paralysis, and eventual death. Here, we have developed a high-throughput zebrafish screen in a 96-well plate format to find new antidotes that counteract organophosphate-induced lethality. In a pilot screen of 1200 known drugs, we identified 16 compounds that suppress organophosphate toxicity in zebrafish. Several in vitro assays coupled with liquid chromatography/tandem mass spectrometry–based metabolite profiling enabled determination of mechanisms of action for several of the antidotes, including reversible acetylcholinesterase inhibition, cholinergic receptor antagonism, and inhibition of bioactivation. Therefore, the in vivo screen is capable of discovering organophosphate antidotes that intervene in distinct pathways. These findings suggest that zebrafish screens might be a broadly applicable approach for discovering compounds that counteract the toxic effects of accidental or malicious poisonous exposures. PMID:22960781

  10. Excessive methaemoglobinaemia and multi-organ failure following 4-DMAP antidote therapy.

    PubMed

    Kerger, Heinz; Dodidou, Petroula; Passani-Kruppa, Daniela; Grüttner, Joachim; Birmelin, Monika; Volz, Alexander; Waschke, Klaus F

    2005-08-01

    This report describes the clinical history of a patient intoxicated with methyl isocyanate (MIC), a toxic agent first receiving attention in 1984 after a mass accident in a pesticide plant in Bhopal, India, and treated with the cyanide-specific antidote 4-DMAP. The numerous clinical conditions requiring 39-day intensive care treatment included ARDS, renal and hepatic failure, haemolysis, bone marrow depression, septic encephalopathy and critical illness polyneuropathy. The most outstanding condition, however, was a methaemoglobinemia of 86.7%, which was predominantly related to the use of 4-DMAP, although uptake of MIC may have been a significant contributing factor. Since significant cyanide intoxication could be excluded clinically and by laboratory testing in the initial phase of emergency treatment, most of the clinical effects were due to the side-effects of the antidote therapy. Due to intensive therapy, the patient survived without any neurological or organ deficit. This case shows that antidotes should be used cautiously in cases where uncertainties about the nature of the underlying toxic agent exist. This may prevent severe side-effects associated with antidote therapy, e.g. 4-DMAP, if there is-as in our case-a mismatch between the toxic agent and the antidote.

  11. Availability of antidotes, antivenoms, and antitoxins in New Zealand hospital pharmacies.

    PubMed

    Fountain, John S; Sly, Brendon; Holt, Alec; MacDonell, Stephen

    2015-03-27

    To assess the adequacy of the types and quantities of antidotes, antivenoms and antitoxins held by New Zealand hospital pharmacies. A list of 61 antidotes, antivenoms, antitoxins and their various forms was developed following literature review and consideration of national pharmaceutical listings. An Internet-accessible survey was then developed, validated and, during the period 28 February to 7 April 2014, sent to 24 hospital pharmacies nationally for completion. Results were assessed and compared with published guidelines for adequate stocking of antidotes in hospitals that provide emergency care. The response rate for the survey was 100%. Wide variation in stock levels were reported with only N- acetylcysteine and octreotide held in adequate quantities by all hospitals to manage a single patient for 24 hours. While archaic compounds were still stocked, newer and more effective pharmaceuticals were not. The national replacement cost for expiring drugs was estimated at $171,024, with smaller, more isolated facilities facing the greatest expense and difficulty in achieving timely resupply. Shortcomings in the types and quantities of antidotes, antivenoms and antitoxins held by New Zealand hospital pharmacies were recognised. This situation may be improved through national rationalisation of pharmaceutical storage and supply, and implementation of a national antidote database.

  12. Ethylene glycol or methanol intoxication: which antidote should be used, fomepizole or ethanol?

    PubMed

    Rietjens, S J; de Lange, D W; Meulenbelt, J

    2014-02-01

    Ethylene glycol (EG) and methanol poisoning can cause life-threatening complications. Toxicity of EG and methanol is related to the production of toxic metabolites by the enzyme alcohol dehydrogenase (ADH), which can lead to metabolic acidosis, renal failure (in EG poisoning), blindness (in methanol poisoning) and death. Therapy consists of general supportive care (e.g. intravenous fluids, correction of electrolytes and acidaemia), the use of antidotes and haemodialysis. Haemodialysis is considered a key element in the treatment of severe EG and methanol intoxication and is aimed at removing both the parent compound and its toxic metabolites, reducing the duration of antidotal treatment and shortening the hospital observation period. Currently, there are two antidotes used to block ADH-mediated metabolism of EG and methanol: ethanol and fomepizole. In this review, the advantages and disadvantages of both antidotes in terms of efficacy, safety and costs are discussed in order to help the physician to decide which antidote is appropriate in a specific clinical setting.

  13. MOKE Diffraction Study of Magnetic Dot and Antidot Arrays.

    NASA Astrophysics Data System (ADS)

    Grimsditch, Marcos

    2003-03-01

    A beam of visible light, incident on a particle array with a submicron period, is diffracted. Extending conventional Magneto Optic Kerr Effect (MOKE) techniques to include the diffracted beams leads to a variety of 'hysteresis' loops. From these loops we show that it is possible to obtain information on the magnetic structure within a unit cell of the array. A brief review of the experimental technique, the theoretical interpretation of the results, and a brief summary of our earlier results on vortices in circular disks [1] and coherent domain formation in antidot arrays [2] will be given. The D-MOKE results from square Permalloy rings will then be presented and compared with micromagnetic simulations. Our results show that magnetization reversal in these ring structures, which is expected to be a jump between two onion states, actually occurs via intermediate, metastable states. For different directions of the applied field these intermediate states are a vortex state or a horseshoe state. A suitable field history allows these states to be quenched and observed using Magnetic Force Microscopy. Work at ANL supported by the US DOE BES Mater. Sci. under contract # W-31-109-ENG-38. [1] M. Grimsditch et al, Phys. Rev. B 65, 172419 (2002) [2] I. Guedes et al, Phys, Rev. B 66, 014434 (2002)

  14. [Chemical weapons: antidotes. View about the real means, perspectives].

    PubMed

    Ricordel, I; Meunier, J

    2000-01-01

    Chemical methods remain a credible threat in 1999. The doctrine for their use not only includes the battlefield but also domestic terrorism as was disclosed during the Tokyo metro attempt in 1995. International Treaties have not yet proven their efficacy. The arsenal of chemical weapons has changed little since the second World War but is now dispersed into many high-risk zones throughout the world. There has also been little change in antidotes: therapeutic prevention with pyridostigmine against organo-phosphorus compounds, protective treatment for seizure-induced brain lesions using anticonvulsants in association with oxime for acetylcholinesterase reactivation, and atropine are combined in a three-compartment syringe. Preventive measures against vesicants and other suffocating or toxic intracellular substances (CN, AsH(3), fluorocarbons.) can only be achieved with protective skin covering or protective breathing devices. There is no specific treatment and we often have to use symptomatic medications. Future perspectives include: phosphotriesterases as organo-phosphorus scavengers, huperzine as pretreatment and gacyclidine (GCK 11) which would effectively complete emergency multiple drug therapy against nerve agents. A new two-compartment syringe is now prepared with atropine, avisafone and HI6 or pralidoxine. A gel made of cyclodextrines for external and eventually internal use is under study.

  15. Antidotes for poisoning by alcohols that form toxic metabolites.

    PubMed

    McMartin, Kenneth; Jacobsen, Dag; Hovda, Knut Erik

    2016-03-01

    The alcohols, methanol, ethylene glycol and diethylene glycol, have many features in common, the most important of which is the fact that the compounds themselves are relatively non-toxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisoning cases, from either unintentional or intentional ingestion. Although relatively infrequent in overall occurrence, poisonings by metabolically-toxic alcohols do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be effective in these poisonings, there are substantial practical problems with its use and so fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically-toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive, or the physician may prefer ethanol due to experience.

  16. Chelators as antidotes of metal toxicity: therapeutic and experimental aspects.

    PubMed

    Blanusa, Maja; Varnai, Veda M; Piasek, Martina; Kostial, Krista

    2005-01-01

    The effects of chelating drugs used clinically as antidotes to metal toxicity are reviewed. Human exposure to a number of metals such as lead, cadmium, mercury, manganese, aluminum, iron, copper, thallium, arsenic, chromium, nickel and platinum may lead to toxic effects, which are different for each metal. Similarly the pharmacokinetic data, clinical use and adverse effects of most of the chelating drugs used in human metal poisoning are also different for each chelating drug. The chelating drugs with worldwide application are dimercaprol (BAL), succimer (meso-DMSA), unithiol (DMPS), D-penicillamine (DPA), N-acetyl-D-penicillamine (NAPA), calcium disodium ethylenediaminetetraacetate (CaNa(2)EDTA), calcium trisodium or zinc trisodium diethylenetriaminepentaacetate (CaNa(3)DTPA, ZnNa(3)DTPA), deferoxamine (DFO), deferiprone (L1), triethylenetetraamine (trientine), N-acetylcysteine (NAC), and Prussian blue (PB). Several new synthetic homologues and experimental chelating agents have been designed and tested in vivo for their metal binding effects. These include three groups of synthetic chelators, namely the polyaminopolycarboxylic acids (EDTA and DTPA), the derivatives of BAL (DMPS, DMSA and mono- and dialkylesters of DMSA) and the carbodithioates. Many factors have been shown to affect the efficacy of the chelation treatment in metal poisoning. Within this context it has been shown in experiments using young and adult animals that metal toxicity and chelation effects could be influenced by age. These findings may have a bearing in the design of new therapeutic chelation protocols for metal toxicity.

  17. Pride and Purpose as Antidotes to Black Homicidal Violence

    PubMed Central

    Thomas, Charles W.

    1987-01-01

    The incidence of black male homicide is a major public menace. The lowest incidence of black male homicide was when the black power movement was visible and flourishing. Psychohistorical data support the contention that racial pride is an effective means for regulating intragroup tensions. In the absence of an Afrocentric orientation that promotes community power and self-determination, the need for self-reliance is eroded by value illnesses. The value orientation of the black movement supplied the pride used to obtain academic success, to reduce juvenile delinquency, and to help Afro-Americans to structure their lives for personal satisfactions. Blackness has always been about personal power and social control, but society does not allow much access to either for Afro-Americans. As a consequence, stress from racism is severe, asymptomatic, and multi-faceted. The best antidote to black homicidal violence comes from a pro-social effort based upon a self-image that gives a feeling of positive accomplishment and appreciation. Afrocentric pride promotes or enhances pro-social behavior. PMID:3560242

  18. Nitrite as an antidote for acute hydrogen sulfide intoxication

    SciTech Connect

    Beck, J.F.; Bradbury, C.M.; Connors, A.J.; Donini, J.C.

    1981-11-01

    The detoxification of hydrogen sulfide (H/sub 2/S) by a heme catalyzed oxidation was examined as part of an on-going study of H/sub 2/S toxicity. Interlocking O/sub 2/ absorption and sulfide depletion data indicate that both oxyhemoglobin and methemoglobin are effective catalytic agents. Although the latter is more efficacious, the life time of excess sulfide in the presence of oxygen and either of the above is of the order of minutes. It has also been established that the formation of methemoglobin following nitrite administration occurs preferentially under oxygen poor conditions. Under an atmospheric or oxygen enriched environment, which favors sulfide depletion, the nitrite retards sulfide oxidation. Thus nitrite as an antidote for acute H/sub 2/S intoxication can only be effective within the first few minutes after the exposure, at which time resuscitation and/or ventilation of the victim is likely to produce conditions in which the nitrite actually slows sulfide removal.

  19. Simulations of two-particle interactions with 2D quantum walks in time

    SciTech Connect

    Schreiber, A.; Laiho, K.; Silberhorn, C.; Rohde, P. P.; Štefaňak, M.; Potoček, V.; Hamilton, C.; Jex, I.

    2014-12-04

    We present the experimental implementation of a quantum walk on a two-dimensional lattice and show how to employ the optical system to simulate the quantum propagation of two interacting particles. Our quantum walk in time transfers the spatial spread of a quantum walk into the time domain, which guarantees a high stability and scalability of the setup. We present with our device quantum walks over 12 steps on a 2D lattice. By changing the properties of the driving quantum coin, we investigate different kinds of two-particle interactions and reveal their impact on the occurring quantum propagation.

  20. Rare events in a finite 2D Ising model

    NASA Astrophysics Data System (ADS)

    Xuan, Ning

    The dynamics of physical systems are always subject to thermal fluctuations or noise. These perturbations will make the stable states of the deterministic part of the dynamical system become only metastable states. When the amplitude of the perturbation is small, the transitions from one metastable state to another are rare events. One such example is the magnetization switching between the two metastable states of 2D Ising model at T < Tc. The 2D Ising model displays two metastable states below the critical temperature Tc. These metastable states are characterized by spontaneous magnetization per spin that tend to m = +/-1 as temperature T → 0. A finite-size Ising system performs transitions from one metastable phase to another due to thermal fluctuations. Such phase transitions often involve growth or birth of a thermally activated critical nucleus, which is statistically a rare event when the noise is small. It may occur via homogeneous nucleation or heterogeneous nucleation, depending on whether the nucleus is formed in system with periodic boundary condition or with boundary condition of Dirichlet or Neumann type. In this thesis, we study the influences of an applied bulk field and local boundary fields to the critical points (minimums and saddle) of noised-driven phase transitions arising in a finite 2D Ising system in both frameworks of the Ginzburg-Landau theory and lattice spins. We use the string method to numerically allocate the minimum energy path (MEP) and the profile of the energy barrier along it. In the framework of Ginzburg-Landau, we introduce an interface energy functional as a sharp interface limit of the Ginzburg-Landau energy, and compare the numerical results from the string method to the analytical results from this interface energy. In the framework of lattice spin model, we first applied the Transition Path Theory to the system to get the transition rate functional that is suitable for both theoretical and numerical purpose. Then the

  1. Multi-resonant optical parametric oscillator based on 2D-PPLT nonlinear photonic crystal.

    PubMed

    Lazoul, Mohamed; Boudrioua, Azzedine; Simohamed, Lotfy-Mokhtar; Peng, Lung-Han

    2015-04-15

    The aim of this work is to achieve an optical parametric oscillator based on two-dimensional periodically poled lithium tantalate (2D-PPLT) crystals that are designed to allow multiple reciprocal lattice-vector contribution to the quasi-phase matching scheme. We are particularly interested in the effect of the multi-wavelength parametric generation performed by the 2D nonlinear photonic crystal to achieve a multi-resonant optical parametric oscillator. The performances are studied in terms of generation efficiency and multi-wavelength generation.

  2. 2D microwave imaging reflectometer electronics

    SciTech Connect

    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.

  3. Large Area Synthesis of 2D Materials

    NASA Astrophysics Data System (ADS)

    Vogel, Eric

    Transition metal dichalcogenides (TMDs) have generated significant interest for numerous applications including sensors, flexible electronics, heterostructures and optoelectronics due to their interesting, thickness-dependent properties. Despite recent progress, the synthesis of high-quality and highly uniform TMDs on a large scale is still a challenge. In this talk, synthesis routes for WSe2 and MoS2 that achieve monolayer thickness uniformity across large area substrates with electrical properties equivalent to geological crystals will be described. Controlled doping of 2D semiconductors is also critically required. However, methods established for conventional semiconductors, such as ion implantation, are not easily applicable to 2D materials because of their atomically thin structure. Redox-active molecular dopants will be demonstrated which provide large changes in carrier density and workfunction through the choice of dopant, treatment time, and the solution concentration. Finally, several applications of these large-area, uniform 2D materials will be described including heterostructures, biosensors and strain sensors.

  4. 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.

  5. Orthotropic Piezoelectricity in 2D Nanocellulose

    PubMed Central

    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

  6. Orthotropic Piezoelectricity in 2D Nanocellulose.

    PubMed

    García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M

    2016-10-06

    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.

  7. 2D microwave imaging reflectometer electronics.

    PubMed

    Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

    2014-11-01

    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.

  8. Generation of propagating spin waves from regions of increased dynamic demagnetising field near magnetic antidots

    SciTech Connect

    Davies, C. S. Kruglyak, V. V.; Sadovnikov, A. V.; Nikitov, S. A.; Grishin, S. V.; Sharaevskii, Yu. P.

    2015-10-19

    We have used Brillouin Light Scattering and micromagnetic simulations to demonstrate a point-like source of spin waves created by the inherently nonuniform internal magnetic field in the vicinity of an isolated antidot formed in a continuous film of yttrium-iron-garnet. The field nonuniformity ensures that only well-defined regions near the antidot respond in resonance to a continuous excitation of the entire sample with a harmonic microwave field. The resonantly excited parts of the sample then served as reconfigurable sources of spin waves propagating (across the considered sample) in the form of caustic beams. Our findings are relevant to further development of magnonic circuits, in which point-like spin wave stimuli could be required, and as a building block for interpretation of spin wave behavior in magnonic crystals formed by antidot arrays.

  9. Detoxification of mercury species--an in vitro study with antidotes in human whole blood.

    PubMed

    Trümpler, Stefan; Nowak, Sascha; Meermann, Björn; Wiesmüller, Gerhard A; Buscher, Wolfgang; Sperling, Michael; Karst, Uwe

    2009-11-01

    To investigate the effects of mercury species intoxication and to test the efficiency of different commonly applied antidotes, human whole blood and plasma surrogate samples were spiked with inorganic mercury (Hg2+) and methylmercury (MeHg+, CH3Hg+) prior to treatment with the antidotes 2,3-dimercaptopropan-1-ol (British Anti Lewisite), 2,3-dimercaptosuccinic acid (DMSA), and N-acetylcysteine (NAC). For mercury speciation analysis in these samples, liquid chromatography was coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). Adduct formation between mercury species and physiological thiols (cysteine and glutathione) was observed as well as the release of glutathione under treatment with the antidotes DMSA and NAC.

  10. Homer's moly identified as Galanthus nivalis L.: physiologic antidote to stramonium poisoning.

    PubMed

    Plaitakis, A; Duvoisin, R C

    1983-03-01

    The antidotal properties of certain naturally occurring medicinal plants against central nervous system intoxication appear to have been empirically established in ancient times. Homer, in his epic poem, the Odyssey, described a plant, "moly," used by Odysseus as an antidote against Circe's poisonous drugs. Centrally acting anticholinergic agents are thought to have been used by Circe to induce amnesia and a delusional state in Odysseus' crew. We present evidence to support the hypothesis that "moly" might have been the snowdrop, Galanthus nivalis, which contains galanthamine, a centrally acting anticholinesterase. Thus the description of "moly" as an antidote in Homer's Odyssey may represent the oldest recorded use of an anticholinesterase to reverse central anticholinergic intoxication.

  11. Assessing 2D electrophoretic mobility spectroscopy (2D MOSY) for analytical applications.

    PubMed

    Fang, Yuan; Yushmanov, Pavel V; Furó, István

    2016-12-08

    Electrophoretic displacement of charged entity phase modulates the spectrum acquired in electrophoretic NMR experiments, and this modulation can be presented via 2D FT as 2D mobility spectroscopy (MOSY) spectra. We compare in various mixed solutions the chemical selectivity provided by 2D MOSY spectra with that provided by 2D diffusion-ordered spectroscopy (DOSY) spectra and demonstrate, under the conditions explored, a superior performance of the former method. 2D MOSY compares also favourably with closely related LC-NMR methods. The shape of 2D MOSY spectra in complex mixtures is strongly modulated by the pH of the sample, a feature that has potential for areas such as in drug discovery and metabolomics. Copyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. StartCopTextCopyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.

  12. 2D Distributed Sensing Via TDR

    DTIC Science & Technology

    2007-11-02

    plate VEGF CompositeSensor Experimental Setup Air 279 mm 61 78 VARTM profile: slope RTM profile: rectangle 22 1 Jul 2003© 2003 University of Delaware...2003 University of Delaware All rights reserved Vision: Non-contact 2D sensing ü VARTM setup constructed within TL can be sensed by its EM field: 2D...300.0 mm/ns. 1 2 1 Jul 2003© 2003 University of Delaware All rights reserved Model Validation “ RTM Flow” TDR Response to 139 mm VEGC

  13. Inkjet printing of 2D layered materials.

    PubMed

    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.

  14. Quaternary and tertiary aldoxime antidotes for organophosphate exposure in a zebrafish model system.

    PubMed

    Schmidt, Hayden R; Radić, Zoran; Taylor, Palmer; Fradinger, Erica A

    2015-04-15

    The zebrafish is rapidly becoming an important model system for screening of new therapeutics. Here we evaluated the zebrafish as a potential pharmacological model for screening novel oxime antidotes to organophosphate (OP)-inhibited acetylcholinesterase (AChE). The ki values determined for chlorpyrifos oxon (CPO) and dichlorvos (DDVP) showed that CPO was a more potent inhibitor of both human and zebrafish AChE, but overall zebrafish AChE was less sensitive to OP inhibition. In contrast, aldoxime antidotes, the quaternary ammonium 2-PAM and tertiary amine RS-194B, showed generally similar overall reactivation kinetics, kr, in both zebrafish and human AChE. However, differences between the Kox and k2 constants suggest that zebrafish AChE associates more tightly with oximes, but has a slower maximal reactivation rate than human AChE. Homology modeling suggests that these kinetic differences result from divergences in the amino acids lining the entrance to the active site gorge. Although 2-PAM had the more favorable in vitro reactivation kinetics, RS-194B was more effective antidote in vivo. In intact zebrafish embryos, antidotal treatment with RS-194B rescued embryos from OP toxicity, whereas 2-PAM had no effect. Dechorionation of the embryos prior to antidotal treatment allowed both 2-PAM and RS-194B to rescue zebrafish embryos from OP toxicity. Interestingly, RS-194B and 2-PAM alone increased cholinergic motor activity in dechorionated embryos possibly due to the reversible inhibition kinetics, Ki and αKi, of the oximes. Together these results demonstrate that the zebrafish at various developmental stages provides an excellent model for investigating membrane penetrant antidotes to OP exposure.

  15. Neuroprotective effects of currently used antidotes in tabun-poisoned rats.

    PubMed

    Kassa, Jirí; Krejèová, Gabriela

    2003-06-01

    The neuroprotective effects of antidotes (atropine, pralidoxime/atropine, obidoxime/atropine and HI-6/atropine mixtures) on rats poisoned with tabun at a lethal dose (220 microg/kg intramuscularly; 100% of LD50 value) were studied. The tabun-induced neurotoxicity was monitored using a functional observational battery and an automatic measurement of motor activity. The neurotoxicity of tabun was monitored at 24 hr and 7 days after tabun challenge. The results indicate that atropine alone is not able to protect the rats from the lethal effects of tabun. Three non-treated tabun-poisoned rats and one tabun-poisoned rat treated with atropine alone died within 24 hr. On the other hand, atropine combined with all tested oximes allows all tabun-poisoned rats to survive at least 7 days following tabun challenge. Obidoxime combined with atropine seems to be the most effective antidotal treatment for the elimination of tabun-induced neurotoxicity in the case of lethal poisoning among tested antidotal mixtures. The antidotal mixture consisting of atropine and HI-6 is significantly less effective than the combination of atropine with obidoxime in the elimination of tabun-induced neurotoxicity in rats at 24 hr following tabun challenge. Pralidoxime in combination with atropine appears to be practically ineffective to decrease tabun-induced neurotoxicity at 24 hours as well as 7 days following tabun poisoning. Due to its neuroprotective effects, obidoxime seems to be the most effective and most suitable oxime for the antidotal treatment of acute tabun exposure among currently used oximes. Thus, the replacement of obidoxime by a more effective acetylcholinesterase reactivator for soman poisoning, the oxime HI-6, can to a small extent diminish the neuroprotective efficacy of antidotal treatment in the case of acute tabun poisonings.

  16. Induction of Glutathione S-Transferase Isozymes in Sorghum by Herbicide Antidotes 1

    PubMed Central

    Dean, John V.; Gronwald, John W.; Eberlein, Charlotte V.

    1990-01-01

    Certain chemicals referred to as herbicide antidotes protect sorghum from injury by chloroacetanilide herbicides such as metolachlor. The effect of herbicide antidotes on the glutathione S-transferase isozyme complement of etiolated sorghum (Sorghum bicolor [L.] Moench) shoots was examined. Elution profiles of glutathione S-transferase isozymes from untreated and antidote-treated seedlings were generated by fast protein liquid chromatography utilizing an anion exchange (Mono Q) column. In untreated seedlings, there were two glutathione S-transferase isozymes, a major isozyme which exhibited activity toward 1-chloro-2,4-dinitrobenzene and a minor isozyme which exhibited activity toward metolachlor. Treating sorghum seedlings with various antidotes (flurazole, oxabetrinil, CGA-133205, naphthalic anhydride, dichlormid) resulted in the appearance of four to five additional glutathione S-transferase isozymes (de-pending on the particular antidote) which exhibited activity toward metolachlor as a substrate and little or no activity with 1-chloro-2,4-dinitrobenzene. Treating etiolated sorghum shoots with metolachlor was also found to induce at least four isozymes which exhibited activity toward the herbicide. An increase in glutathione S-transferase activity, measured with metolachlor as substrate, was detected within 4 h after treatment with 30 micromolar oxabetrinil, but 36 hours were required for maximum expression of activity. Addition of either the transcription inhibitor cordycepin or the translation inhibitor cycloheximide inhibited the appearance of glutathione S-transferase activity measured with metolachlor as substrate. The results are consistent with the hypothesis that antidotes confer protection against metolachlor injury in sorghum by inducing the de novo synthesis of glutathione S-transferase isozymes which catalyze the detoxification of the herbicide. PMID:16667299

  17. Estimating the Quantitative Demand of NOAC Antidote Doses on Stroke Units.

    PubMed

    Pfeilschifter, Waltraud; Farahmand, Dana; Niemann, Daniela; Ikenberg, Benno; Hohmann, Carina; Abruscato, Mario; Thonke, Sven; Strzelczyk, Adam; Hedtmann, Günther; Neumann-Haefelin, Tobias; Kollmar, Rainer; Singer, Oliver C; Ferbert, Andreas; Steiner, Thorsten; Steinmetz, Helmuth; Reihs, Anke; Misselwitz, Björn; Foerch, Christian

    2016-01-01

    The first specific antidote for non-vitamin K antagonist oral anticoagulants (NOAC) has recently been approved. NOAC antidotes will allow specific treatment for 2 hitherto problematic patient groups: patients with oral anticoagulant therapy (OAT)-associated intracerebral hemorrhage (ICH) and maybe also thrombolysis candidates presenting on oral anticoagulation (OAT). We aimed to estimate the frequency of these events and hence the quantitative demand of antidote doses on a stroke unit. We extracted data of patients with acute ischemic stroke and ICH (<24 h after symptom onset) in the years 2012-2015 from a state-wide prospective stroke inpatient registry. We selected 8 stroke units and determined the mode of OAT upon admission in 2012-2013. In 2015, the mode of OAT became a mandatory item of the inpatient registry. From the number of anticoagulated patients and the NOAC share, we estimated the current and future demand for NOAC antidote doses on stroke units. Eighteen percent of ICH patients within 6 h of symptom onset or an unknown symptom onset were on OAT. Given a NOAC share at admission of 40%, about 7% of all ICH patients may qualify for NOAC reversal therapy. Thirteen percent of ischemic stroke patients admitted within 4 h presented on anticoagulation. Given the availability of an appropriate antidote, a NOAC share of 50% could lead to a 6.1% increase in thrombolysis rate. Stroke units serving populations with a comparable demographic structure should prepare to treat up to 1% of all acute ischemic stroke patients and 7% of all acute ICH patients with NOAC antidotes. These numbers may increase with the mounting prevalence of atrial fibrillation and an increasing use of NOAC. © 2016 S. Karger AG, Basel.

  18. Statistical Transmutation in Floquet Driven Optical Lattices.

    PubMed

    Sedrakyan, Tigran A; Galitski, Victor M; Kamenev, Alex

    2015-11-06

    We show that interacting bosons in a periodically driven two dimensional (2D) optical lattice may effectively exhibit fermionic statistics. The phenomenon is similar to the celebrated Tonks-Girardeau regime in 1D. The Floquet band of a driven lattice develops the moat shape, i.e., a minimum along a closed contour in the Brillouin zone. Such degeneracy of the kinetic energy favors fermionic quasiparticles. The statistical transmutation is achieved by the Chern-Simons flux attachment similar to the fractional quantum Hall case. We show that the velocity distribution of the released bosons is a sensitive probe of the fermionic nature of their stationary Floquet state.

  19. Magnetic antidot arrays using SiO2 filled diblock copolymer micelles as ion etching mask

    NASA Astrophysics Data System (ADS)

    Pütter, S.; Stillrich, H.; Frömsdorf, A.; Menk, C.; Frömter, R.; Förster, S.; Oepen, H. P.

    2007-09-01

    We present a simple method for the production of magnetic antidot arrays utilizing polystyrene-poly-2-vinylpyridine micelles filled with amorphous SiO2. By dip coating, a micellar monolayer is deposited onto Co/Pt multilayers. A hexagonal pattern with periodicity of 80 nm is obtained. By Ar+ ion etching the micelle layer is transformed into an antidot array due to preferred sputtering of the SiO2 core. Further ion bombardment transfers the pattern into the magnetic film and leads to a reorientation of the perpendicular to in-plane easy axis which is attributed to intermixing of the Co/Pt multilayers.

  20. The Copernican Revolution as Story: an Antidote for Scientific Illiteracy

    NASA Astrophysics Data System (ADS)

    Wallace, P. M.

    2005-08-01

    ``When a white-robed scientist, momentarily looking away from his microscope or cyclotron [or telescope], makes some pronouncement for the general public, he may not be understood but at least he is certain to be believed.'' The truth of this opening sentence of Anthony Standen's 1950 book Science is a Sacred Cow, as clear today as it was then, is the motivation for a new astronomy course at Berry College near Atlanta, GA, USA. To non-scientists, science is known by its products, not by what it is: a human progress. For this illiteracy an antidote is offered: the history of astronomy. In this course the story of the Copernican Revolution is told, for within this story the true nature of science can be found in its fullness. For example, Aristotle's uniform circular motion is used to emphasize the role of assumptions, and the occasional value of wrong ideas is evident in Tycho's theory and in Kepler's universe of perfect solids. Tycho's observations of Mars and Kepler's analysis illustrate the interplay of observation, theory, and technology. As a final example, the indirectness and often-unintentional nature of scientific advance can be seen in the work of Copernicus. The roles of personality and the intersections of science and society are themes throughout the course, as are the merging of disparate fields and the power of strong theories. There are other themes (e.g., coherence, the role of mathematics), but the emphasis is on the science and much of the work is quantitative. There is a laboratory component that features observations and experiments, and in order to bring the narrative to life the class spends two weeks in Poland, the Czech Republic, and Italy, touring sites that are relevant to the story of the Copernican Revolution.

  1. Multifunctional drugs as novel antidotes for organophosphates' poisoning.

    PubMed

    Weissman, Ben Avi; Raveh, Lily

    2011-12-18

    Some organophosphorus compounds (OPs) are nerve agents that continue to concern military personnel and civilians as potential battlefield and terrorist threats. Additionally, OPs are used in agriculture where they are associated with numerous cases of intentional and accidental misuse. These toxicants induce an array of deleterious effects including respiratory distress, convulsions and ultimately death. A mechanism involving a rapid and potent inhibition of peripheral and central cholinesterases leading to a massive buildup of acetylcholine in synaptic clefts was suggested as the underlying trigger of the toxic events. Indeed, therapy comprised of an acetylcholinesterase reactivator (i.e., oxime) and a cholinergic antagonist (e.g., atropine) is the accepted major paradigm for protection. This approach yields a remarkable survival rate but fails to prevent neurological and behavioral deficits. Extensive research revealed a complex picture consisting of an early activation of several neurotransmitter systems, in which the glutamatergic plays a pivotal role., Data accumulated in recent years support the concept that multi-targeting of pathways including glutamatergic and cholinergic circuits is required for an effective treatment. Drugs that demonstrate the ability to interact with several systems (e.g., caramiphen) were found to afford a superior protection against OPs as compared to specific antimuscarinic ligands (e.g., scopolamine). Compounds that potently block muscarinic receptors, interact with the NMDA ion channel and in addition are able to modulate σ(1) sites and/or GABAergic transmission seem to represent the emerging backbone for novel antidotes against OP poisoning. Several multifunctional drugs are already used for complex diseases e.g., cancer and depression.

  2. N-acetylcysteine amide, a promising antidote for acetaminophen toxicity.

    PubMed

    Khayyat, Ahdab; Tobwala, Shakila; Hart, Marcia; Ercal, Nuran

    2016-01-22

    Acetaminophen (N-acetyl-p-aminophenol, APAP) is one of the most widely used over the counter antipyretic and analgesic medications. It is safe at therapeutic doses, but its overdose can result in severe hepatotoxicity, a leading cause of drug-induced acute liver failure in the USA. Depletion of glutathione (GSH) is one of the initiating steps in APAP-induced hepatotoxicity; therefore, one strategy for restricting organ damage is to restore GSH levels by using GSH prodrugs. N-acetylcysteine (NAC), a GSH precursor, is the only currently approved antidote for an acetaminophen overdose. Unfortunately, fairly high doses and longer treatment times are required due to its poor bioavailability. In addition, oral and I.V. administration of NAC in a hospital setting are laborious and costly. Therefore, we studied the protective effects of N-acetylcysteine amide (NACA), a novel antioxidant with higher bioavailability, and compared it with NAC in APAP-induced hepatotoxicity in C57BL/6 mice. Our results showed that NACA is better than NAC at a low dose (106mg/kg) in preventing oxidative stress and protecting against APAP-induced damage. NACA significantly increased GSH levels and the GSH/GSSG ratio in the liver to 66.5% and 60.5% of the control, respectively; and it reduced the level of ALT by 30%. However, at the dose used, NAC was not effective in combating the oxidative stress induced by APAP. Thus, NACA appears to be better than NAC in reducing the oxidative stress induced by APAP. It would be of great value in the health care field to develop drugs like NACA as more effective and safer options for the prevention and therapeutic intervention in APAP-induced toxicity.

  3. Parallel Stitching of 2D Materials.

    PubMed

    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.

  4. Parallel stitching of 2D materials

    SciTech Connect

    Ling, Xi; Wu, Lijun; 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; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomas; Kong, Jing

    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.

  5. The basics of 2D DIGE.

    PubMed

    Beckett, Phil

    2012-01-01

    The technique of two-dimensional (2D) gel electrophoresis is a powerful tool for separating complex mixtures of proteins, but since its inception in the mid 1970s, it acquired the stigma of being a very difficult application to master and was generally used to its best effect by experts. The introduction of commercially available immobilized pH gradients in the early 1990s provided enhanced reproducibility and easier protocols, leading to a pronounced increase in popularity of the technique. However gel-to-gel variation was still difficult to control without the use of technical replicates. In the mid 1990s (at the same time as the birth of "proteomics"), the concept of multiplexing fluorescently labeled proteins for 2D gel separation was realized by Jon Minden's group and has led to the ability to design experiments to virtually eliminate gel-to-gel variation, resulting in biological replicates being used for statistical analysis with the ability to detect very small changes in relative protein abundance. This technology is referred to as 2D difference gel electrophoresis (2D DIGE).

  6. Parallel stitching of 2D materials

    DOE PAGES

    Ling, Xi; Wu, Lijun; Lin, Yuxuan; ...

    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.

  7. Kondo lattice without Nozieres exhaustion effect.

    SciTech Connect

    Kikoin, K.; Kiselev, M. N.; Materials Science Division; Ben-Gurion Univ. of the Negev; Ludwig-Maximilians Univ.

    2006-01-01

    We discuss the properties of layered Anderson/Kondo lattices with metallic electrons confined in 2D xy planes and local spins in insulating layers forming chains in the z direction. Each spin in this model possesses its own 2D Kondo cloud, so that the Nozieres exhaustion problem does not occur. The high-temperature perturbational description is matched to exact low-T Bethe-ansatz solution. The excitation spectrum of the model is gapless both in charge and spin sectors. The disordered phases and possible experimental realizations of the model are briefly discussed.

  8. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    PubMed Central

    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

  9. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    PubMed

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    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.

  10. 2D to 3D transition of polymeric carbon nitride nanosheets

    SciTech Connect

    Chamorro-Posada, Pedro; Vázquez-Cabo, José; Martín-Ramos, Pablo; Martín-Gil, Jesús; Navas-Gracia, Luis M.; Dante, Roberto C.

    2014-11-15

    The transition from a prevalent turbostratic arrangement with low planar interactions (2D) to an array of polymeric carbon nitride nanosheets with stronger interplanar interactions (3D), occurring for samples treated above 650 °C, was detected by terahertz-time domain spectroscopy (THz-TDS). The simulated 3D material made of stacks of shifted quasi planar sheets composed of zigzagged polymer ribbons, delivered a XRD simulated pattern in relatively good agreement with the experimental one. The 2D to 3D transition was also supported by the simulation of THz-TDS spectra obtained from quantum chemistry calculations, in which the same broad bands around 2 THz and 1.5 THz were found for 2D and 3D arrays, respectively. This transition was also in accordance with the tightening of the interplanar distance probably due to an interplanar π bond contribution, as evidenced also by a broad absorption around 2.6 eV in the UV–vis spectrum, which appeared in the sample treated at 650 °C, and increased in the sample treated at 700 °C. The band gap was calculated for 1D and 2D cases. The value of 3.374 eV for the 2D case is, within the model accuracy and precision, in a relative good agreement with the value of 3.055 eV obtained from the experimental results. - Graphical abstract: 2D lattice mode vibrations and structural changes correlated with the so called “2D to 3D transition”. - Highlights: • A 2D to 3D transition has been detected for polymeric carbon nitride. • THz-TDS allowed us to discover and detect the 2D to 3D transition of polymeric carbon nitride. • We propose a structure for polymeric carbon nitride confirming it with THz-TDS.

  11. Novel nerve-agent antidote design based on crystallographic and mass spectrometric analyses of tabun-conjugated acetylcholinesterase in complex with antidotes.

    PubMed

    Ekström, F J; Astot, C; Pang, Y-P

    2007-09-01

    Organophosphorus compound-based nerve agents inhibit the essential enzyme acetylcholinesterase (AChE) causing acute toxicity and death. Clinical treatment of nerve-agent poisoning is to use oxime-based antidotes to reactivate the inhibited AChE. However, the nerve agent tabun is resistant to oximes. To design improved oximes, crystal structures of a tabun-conjugated AChE in complex with different oximes are needed to guide the structural modifications of known antidotes. However, this type of structure is extremely challenging to obtain because both deamidation of the tabun conjugate and reactivation of AChE occur during crystallographic experiments. Here we report, for the first time, the crystal structures of Ortho-7 and HLö-7 in complex with AChE that is conjugated to an intact tabun. These structures were determined by our new strategy of combining crystallographic and mass spectrometric analyses of AChE crystals. The results explain the relative reactivation potencies of the two oximes and offer insights into improving known medical antidotes.

  12. Extrinsic Cation Selectivity of 2D Membranes

    PubMed Central

    2017-01-01

    From a systematic study of the concentration driven diffusion of positive and negative ions across porous 2D membranes of graphene and hexagonal boron nitride (h-BN), we prove their cation selectivity. Using the current–voltage characteristics of graphene and h-BN monolayers separating reservoirs of different salt concentrations, we calculate the reversal potential as a measure of selectivity. We tune the Debye screening length by exchanging the salt concentrations and demonstrate that negative surface charge gives rise to cation selectivity. Surprisingly, h-BN and graphene membranes show similar characteristics, strongly suggesting a common origin of selectivity in aqueous solvents. For the first time, we demonstrate that the cation flux can be increased by using ozone to create additional pores in graphene while maintaining excellent selectivity. We discuss opportunities to exploit our scalable method to use 2D membranes for applications including osmotic power conversion. PMID:28157333

  13. Schottky diodes from 2D germanane

    NASA Astrophysics Data System (ADS)

    Sahoo, Nanda Gopal; Esteves, Richard J.; Punetha, Vinay Deep; Pestov, Dmitry; Arachchige, Indika U.; McLeskey, James T.

    2016-07-01

    We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe2 framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.

  14. Schottky diodes from 2D germanane

    SciTech Connect

    Sahoo, Nanda Gopal; Punetha, Vinay Deep; Esteves, Richard J; Arachchige, Indika U.; Pestov, Dmitry; McLeskey, James T.

    2016-07-11

    We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe{sub 2} framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.

  15. Compatible embedding for 2D shape animation.

    PubMed

    Baxter, William V; Barla, Pascal; Anjyo, Ken-Ichi

    2009-01-01

    We present new algorithms for the compatible embedding of 2D shapes. Such embeddings offer a convenient way to interpolate shapes having complex, detailed features. Compared to existing techniques, our approach requires less user input, and is faster, more robust, and simpler to implement, making it ideal for interactive use in practical applications. Our new approach consists of three parts. First, our boundary matching algorithm locates salient features using the perceptually motivated principles of scale-space and uses these as automatic correspondences to guide an elastic curve matching algorithm. Second, we simplify boundaries while maintaining their parametric correspondence and the embedding of the original shapes. Finally, we extend the mapping to shapes' interiors via a new compatible triangulation algorithm. The combination of our algorithms allows us to demonstrate 2D shape interpolation with instant feedback. The proposed algorithms exhibit a combination of simplicity, speed, and accuracy that has not been achieved in previous work.

  16. Stochastic Inversion of 2D Magnetotelluric Data

    SciTech Connect

    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

  17. Static & Dynamic Response of 2D Solids

    SciTech Connect

    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.

  18. Explicit 2-D Hydrodynamic FEM Program

    SciTech Connect

    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.

  19. PdSe2: Pentagonal 2D Layers with High Air Stability for Electronics

    DOE PAGES

    Ghosh, Avik W.; Yu, Peng; Liu, Zheng; ...

    2017-09-01

    Most studied two-dimensional (2D) materials exhibit isotropic behavior due to high lattice symmetry; however, lower-symmetry 2D materials such as phosphorene and other elemental 2D materials exhibit very interesting anisotropic properties. In this work, we report the atomic structure, electronic properties, and vibrational modes of few-layered PdSe2, exfoliated from bulk crystals, a pentagonal 2D layered noble transition metal dichalcogenide with a puckered morphology that is air-stable. Micro-absorption optical spectroscopy and first-principles calculations reveal a wide band gap variation in this material from ~0 (bulk) to ~1.3 eV (monolayer). The Raman active vibrational modes of PdSe2 were identified using polarized Raman spectroscopy,more » and the strong interlayer interaction was revealed from the large thickness-dependent Raman peak shifts, agreeing with first-principles Raman simulations. Field-effect transistors made from the few-layer PdSe2 display tunable ambipolar charge carrier conduction with a high electron apparent field-effect mobility of ~158 cm2V-1s-1, indicating the promise of this anisotropic, air-stable, pentagonal 2D material for 2D electronics.« less

  20. Sparse and incomplete factorial matrices to screen membrane protein 2D crystallization

    PubMed Central

    Lasala, R.; Coudray, N.; Abdine, A.; Zhang, Z.; Lopez-Redondo, M.; Kirshenbaum, R.; Alexopoulos, J.; Zolnai, Z.; Stokes, D.L.; Ubarretxena-Belandia, I.

    2014-01-01

    Electron crystallography is well suited for studying the structure of membrane proteins in their native lipid bilayer environment. This technique relies on electron cryomicroscopy of two-dimensional (2D) crystals, grown generally by reconstitution of purified membrane proteins into proteoliposomes under conditions favoring the formation of well-ordered lattices. Growing these crystals presents one of the major hurdles in the application of this technique. To identify conditions favoring crystallization a wide range of factors that can lead to a vast matrix of possible reagent combinations must be screened. However, in 2D crystallization these factors have traditionally been surveyed in a relatively limited fashion. To address this problem we carried out a detailed analysis of published 2D crystallization conditions for 12 β-barrel and 138 α-helical membrane proteins. From this analysis we identified the most successful conditions and applied them in the design of new sparse and incomplete factorial matrices to screen membrane protein 2D crystallization. Using these matrices we have run 19 crystallization screens for 16 different membrane proteins totaling over 1,300 individual crystallization conditions. Six membrane proteins have yielded diffracting 2D crystals suitable for structure determination, indicating that these new matrices show promise to accelerate the success rate of membrane protein 2D crystallization. PMID:25478971

  1. Highly resolved measurements of atmospheric turbulence with the new 2d-Atmospheric Laser Cantilever Anemometer

    NASA Astrophysics Data System (ADS)

    Jeromin, A.; Schaffarczyk, A. P.; Puczylowski, J.; Peinke, J.; Hölling, M.

    2014-12-01

    For the investigation of atmospheric turbulent flows on small scales a new anemometer was developed, the so-called 2d-Atmospheric Laser Cantilever Anemometer (2d-ALCA). It performs highly resolved measurements with a spatial resolution in millimeter range and temporal resolution in kHz range, thus detecting very small turbulent structures. The anemometer is a redesign of the successfully operating 2d-LCA for laboratory application. The new device was designed to withstand hostile operating environments (rain and saline, humid air). In February 2012, the 2d-ALCA was used for the first time in a test field. The device was mounted in about 53 m above ground level on a lattice tower near the German North Sea coast. Wind speed was measured by the 2d-ALCA at 10 kHz sampling rate and by cup anemometers at 1 Hz. The instantaneous wind speed ranged from 8 m/s to 19 m/s at an average turbulence level of about 7 %. Wind field characteristics were analyzed based on cup anemometer as well as 2d-ALCA. The combination of both devices allowed the study of atmospheric turbulence over several magnitudes in turbulent scales.

  2. Sparse and incomplete factorial matrices to screen membrane protein 2D crystallization.

    PubMed

    Lasala, R; Coudray, N; Abdine, A; Zhang, Z; Lopez-Redondo, M; Kirshenbaum, R; Alexopoulos, J; Zolnai, Z; Stokes, D L; Ubarretxena-Belandia, I

    2015-02-01

    Electron crystallography is well suited for studying the structure of membrane proteins in their native lipid bilayer environment. This technique relies on electron cryomicroscopy of two-dimensional (2D) crystals, grown generally by reconstitution of purified membrane proteins into proteoliposomes under conditions favoring the formation of well-ordered lattices. Growing these crystals presents one of the major hurdles in the application of this technique. To identify conditions favoring crystallization a wide range of factors that can lead to a vast matrix of possible reagent combinations must be screened. However, in 2D crystallization these factors have traditionally been surveyed in a relatively limited fashion. To address this problem we carried out a detailed analysis of published 2D crystallization conditions for 12 β-barrel and 138 α-helical membrane proteins. From this analysis we identified the most successful conditions and applied them in the design of new sparse and incomplete factorial matrices to screen membrane protein 2D crystallization. Using these matrices we have run 19 crystallization screens for 16 different membrane proteins totaling over 1300 individual crystallization conditions. Six membrane proteins have yielded diffracting 2D crystals suitable for structure determination, indicating that these new matrices show promise to accelerate the success rate of membrane protein 2D crystallization. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. 2D Metals by Repeated Size Reduction.

    PubMed

    Liu, Hanwen; Tang, Hao; Fang, Minghao; Si, Wenjie; Zhang, Qinghua; Huang, Zhaohui; Gu, Lin; Pan, Wei; Yao, Jie; Nan, Cewen; Wu, Hui

    2016-10-01

    A general and convenient strategy for manufacturing freestanding metal nanolayers is developed on large scale. By the simple process of repeatedly folding and calendering stacked metal sheets followed by chemical etching, free-standing 2D metal (e.g., Ag, Au, Fe, Cu, and Ni) nanosheets are obtained with thicknesses as small as 1 nm and with sizes of the order of several micrometers.

  4. 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.

  5. Quasiparticle interference in unconventional 2D systems

    NASA Astrophysics Data System (ADS)

    Chen, Lan; Cheng, Peng; Wu, Kehui

    2017-03-01

    At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe2), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.

  6. 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.

  7. 2D materials: Graphene and others

    SciTech Connect

    Bansal, Suneev Anil Singh, Amrinder Pal; Kumar, Suresh

    2016-05-06

    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.

  8. 2dF mechanical engineering

    NASA Astrophysics Data System (ADS)

    Smith, Greg; Lankshear, Allan

    1998-07-01

    2dF is a multi-object instrument mounted at prime focus at the AAT capable of spectroscopic analysis of 400 objects in a single 2 degree field. It also prepares a second 2 degree 400 object field while the first field is being observed. At its heart is a high precision robotic positioner that places individual fiber end magnetic buttons on one of two field plates. The button gripper is carried on orthogonal gantries powered by linear synchronous motors and contains a TV camera which precisely locates backlit buttons to allow placement in user defined locations to 10 (mu) accuracy. Fiducial points on both plates can also be observed by the camera to allow repeated checks on positioning accuracy. Field plates rotate to follow apparent sky rotation. The spectrographs both analyze light from the 200 observing fibers each and back- illuminate the 400 fibers being re-positioned during the observing run. The 2dF fiber position and spectrograph system is a large and complex instrument located at the prime focus of the Anglo Australian Telescope. The mechanical design has departed somewhat from the earlier concepts of Gray et al, but still reflects the audacity of those first ideas. The positioner is capable of positioning 400 fibers on a field plate while another 400 fibers on another plate are observing at the focus of the telescope and feeding the twin spectrographs. When first proposed it must have seemed like ingenuity unfettered by caution. Yet now it works, and works wonderfully well. 2dF is a system which functions as the result of the combined and coordinated efforts of the astronomers, the mechanical designers and tradespeople, the electronic designers, the programmers, the support staff at the telescope, and the manufacturing subcontractors. The mechanical design of the 2dF positioner and spectrographs was carried out by the mechanical engineering staff of the AAO and the majority of the manufacture was carried out in the AAO workshops.

  9. Chemical and metabolomic screens identify novel biomarkers and antidotes for cyanide exposure.

    PubMed

    Nath, Anjali K; Roberts, Lee D; Liu, Yan; Mahon, Sari B; Kim, Sonia; Ryu, Justine H; Werdich, Andreas; Januzzi, James L; Boss, Gerry R; Rockwood, Gary A; MacRae, Calum A; Brenner, Matthew; Gerszten, Robert E; Peterson, Randall T

    2013-05-01

    Exposure to cyanide causes a spectrum of cardiac, neurological, and metabolic dysfunctions that can be fatal. Improved cyanide antidotes are needed, but the ideal biological pathways to target are not known. To understand better the metabolic effects of cyanide and to discover novel cyanide antidotes, we developed a zebrafish model of cyanide exposure and scaled it for high-throughput chemical screening. In a screen of 3120 small molecules, we discovered 4 novel antidotes that block cyanide toxicity. The most potent antidote was riboflavin. Metabolomic profiling of cyanide-treated zebrafish revealed changes in bile acid and purine metabolism, most notably by an increase in inosine levels. Riboflavin normalizes many of the cyanide-induced neurological and metabolic perturbations in zebrafish. The metabolic effects of cyanide observed in zebrafish were conserved in a rabbit model of cyanide toxicity. Further, humans treated with nitroprusside, a drug that releases nitric oxide and cyanide ions, display increased circulating bile acids and inosine. In summary, riboflavin may be a novel treatment for cyanide toxicity and prophylactic measure during nitroprusside treatment, inosine may serve as a biomarker of cyanide exposure, and metabolites in the bile acid and purine metabolism pathways may shed light on the pathways critical to reversing cyanide toxicity.

  10. Development of biochemical and transformation cyanide antidotes. Final report, 13 January 1993-12 January 1996

    SciTech Connect

    Isom, G.E.

    1996-02-01

    Work for this contract involved both cyanide (Part 1) and sulfur mustard vesicants (Part 2). Part (1) To develop an in vitro screen for cyanide antidotes, compounds were tested empirically for ability to block the biochemical effects of cyanide in isolated rat pheochromocytoma (PC 12) cells. Effects in vitro were then compared to ability to block cyanide toxicity in mice. Of the five biochemical actions of cyanide tested, blockade of catalase activity was the one most correlated with in vivo protection. Overall, significant correlations were found between catalase protection in vitro and cyanide antidotal effects in vivo. Data involving 40 different chemical compounds showed that approximately 75% of the time, the in vitro assay was predictive of effectiveness in vivo. The results indicate that the ability of a compound to protect catalase in cultured PC 12 cells against cyanide is a useful screen for cyanide antidotal action in mice. Part (2) To develop an in vitro screen for antivesicant compounds. Mechanisms by which sulfur mustards cause cell death were studied in differentiated PC 12 cells. Both the `Apotag` method and electron microscopy indicated that apoptosis occurred after sulfur mustard exposure. A necrotic mechanism was also evident at higher concentrations (>10-4M). It may be possible to identify sulfur mustard antidotes by their ability to block each of these mechanisms in differentiated PC12 cells.

  11. Acceleration of Advanced CN Antidote Agents for Mass Exposure Treatments: DMTS

    DTIC Science & Technology

    2014-12-01

    diffuse optical spectroscopy (DOS) and continuous wave near infrared spectroscopy (CWNIRS), inhaled and exhaled breath gas exchange parameters, blood...venous lines, and inhaled and exhaled gas analysis. Animals are given intramuscular antidote injection (or control vehicle injection) when they...programs. We continue to examine various metabolic parameters including oxy and deoxyhemoglobin, inhaled and exhaled gas exchange (anaerobic threshold

  12. Thallium toxicity: The problem; an analytical approach; an antidotal study. Master's thesis

    SciTech Connect

    Mulkey, J.P.

    1993-03-15

    Thallium (Tl) is a highly toxic metal that is anthropogenically concentrated in the environment. Tl toxicity and the quantitative analysis of trace levels of Tl in biologic materials by atomic absorption spectroscopy is reviewed; a study designed to evaluate the antidotal efficacy of 2 compounds in the treatment of acute Tl toxicity in rats is documented. Unithiol (2,3-dimercapto-1-propanesulfonic acid, DMPS) and prussian blue (potassium ferric hexacyanoferrate(II), PB), given alone and in combination, were evaluated as antidotes in the treatment of acute thallotoxicosis in male Sprauge-Dawley rats. The relative accumulation of Tl in organs was kidney>>heart>liver-brain. PB induced significant decorporation of Tl from all tissues. DMPS failed to significantly decrease the Tl content in any organ, but significantly decreased the Tl content in whole blood. PB+DMPS treatment significantly decreased the Tl content in all organs, but to no greater extent than PB alone. PB and PB+DMPS treatments significantly increased the Tl content of feces, whereas DMPS treatment alone produced little effect. This study indicates that PB is a beneficial antidote in the treatment of acute thallotoxicosis in rats. The failure of DMPS to significantly decrease the Tl content in 4 target organs suggests it would not be useful in the treatment of Tl poisoning....Thallium, Poison, Antidote, Chelator, Prussian blue, Potassium ferric hexacyanoferrate(II), Unithiol, 2,3-dimercapto-1-propanesulfonic acid, Rat.

  13. Development of a recombinant antithrombin variant as a potent antidote to fondaparinux and other heparin derivatives.

    PubMed

    Bianchini, Elsa P; Fazavana, Judicael; Picard, Veronique; Borgel, Delphine

    2011-02-10

    Heparin derivative-based therapy has evolved from unfractionated heparin (UFH) to low-molecular-weight heparins (LMWHs) and now fondaparinux, a synthetic pentasaccharide. Contrary to UFH or LMWHs, fondaparinux is not neutralized by protamine sulfate, and no antidote is available to counteract bleeding disorders associated with overdosing. To make the use of fondaparinux safer, we developed an antithrombin (AT) variant as a potent antidote to heparin derivatives. This variant (AT-N135Q-Pro394) combines 2 mutations: substitution of Asn135 by a Gln to remove a glycosylation site and increase affinity for heparins, and the insertion of a Pro between Arg393 and Ser394 to abolish its anticoagulant activity. As expected, AT-N135Q-Pro394 anticoagulant activity was almost abolished, and it exhibited a 3-fold increase in fondaparinux affinity. AT-N135Q-Pro394 was shown to reverse fondaparinux overdosing in vitro in a dose-dependent manner through a competitive process with plasma AT for fondaparinux binding. This antidote effect was also observed in vivo: administration of AT-N135Q-Pro394 in 2.5-fold molar excess versus plasma AT neutralized 86% of the anti-Xa activity within 5 minutes in mice treated with fondaparinux. These results clearly demonstrate that AT-N135Q-Pro394 can reverse the anticoagulant activity of fondaparinux and thus could be used as an antidote for this drug.

  14. Prehospital diagnosis of massive ethylene glycol poisoning and use of an early antidote.

    PubMed

    Amathieu, Roland; Merouani, Medhi; Borron, Stephen W; Lapostolle, Frédéric; Smail, Nadia; Adnet, Frédéric

    2006-08-01

    We report the case of a patient suspected of voluntary massive poisoning by ethylene glycol. Prehospital diagnosis was established by portable blood analyser and an early antidote with 4 MP treatment initiated in out-of-hospital setting. Use of portable blood analyser in prehospital care should be considered in case of suspected massive poisoning by ethylene glycol.

  15. Insufficient stocking of cyanide antidotes in US hospitals that provide emergency care.

    PubMed

    Gasco, Lucas; Rosbolt, Margaret B; Bebarta, Vikhyat S

    2013-04-01

    To identify the influence of catchment area, trauma center designation, hospital size, subspecialist employment, funding source, and other hospital characteristics on cyanide antidote stocking choice in US hospitals that provides emergency care. A web-based survey was sent out to pharmacy managers through two listservs; the American Society of Health-Systems Pharmacists and the American College of Clinical Pharmacy. A medical marketing company also broadcasted the survey to 2,659 individuals. We collected data on hospital characteristics (size, state, serving population, etc.,) to determine what influenced the hospital's stocking choice. The survey response rate was approximately 10% (n = 286). Thirty-eight hospitals (16%) stocked at least 4 antidote kits. Safety profile, recommendations from a poison control center, and ease of use had the strongest influence on stocking decisions. Survey of 286 US hospital pharmacy managers, 38/234 (16%) hospitals had sufficient stocking of cyanide antidotes. Antidote preference was based on safety, ease of use, and recommendations by the local poison center, over cost.

  16. Cyanide Antidotes for Mass Casualties: Comparison of Intramuscular Injector by Autoinjector, Intraosseous Injection, and Inhalational Delivery

    DTIC Science & Technology

    2013-10-01

    held high- throughput ultrasonic monodisperse aerosol inhalers for detoxification of massive CN poisoning. IV. CONCLUSIONS Significant effect of...Comparison of Intramuscular Injector by Autoinjector, Intraosseous Injection, and Inhalational Delivery PRINCIPAL INVESTIGATOR: Gerry R...Antidotes for Mass Casualties: Comparison of Intramuscular Injector by Autoinjector, Intraosseous Injection, and Inhalational Delivery 5a. CONTRACT

  17. Engineering light outcoupling in 2D materials.

    PubMed

    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.

  18. Irreversibility-inversions in 2D turbulence

    NASA Astrophysics Data System (ADS)

    Bragg, Andrew; de Lillo, Filippo; Boffetta, Guido

    2016-11-01

    We consider a recent theoretical prediction that for inertial particles in 2D turbulence, the nature of the irreversibility of their pair dispersion inverts when the particle inertia exceeds a certain value. In particular, when the particle Stokes number, St , is below a certain value, the forward-in-time (FIT) dispersion should be faster than the backward-in-time (BIT) dispersion, but for St above this value, this should invert so that BIT becomes faster than FIT dispersion. This non-trivial behavior arises because of the competition between two physically distinct irreversibility mechanisms that operate in different regimes of St . In 3D turbulence, both mechanisms act to produce faster BIT than FIT dispersion, but in 2D, the two mechanisms have opposite effects because of the inverse energy cascade in the turbulent velocity field. We supplement the qualitative argument given by Bragg et al. by deriving quantitative predictions of this effect in the short-time dispersion limit. These predictions are then confirmed by results of inertial particle dispersion in a direct numerical simulation of 2D turbulence.

  19. MAGNUM-2D computer code: user's guide

    SciTech Connect

    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.

  20. Quaternary and tertiary aldoxime antidotes for organophosphate exposure in a zebrafish model system

    SciTech Connect

    Schmidt, Hayden R.; Radić, Zoran; Taylor, Palmer; Fradinger, Erica A.

    2015-04-15

    The zebrafish is rapidly becoming an important model system for screening of new therapeutics. Here we evaluated the zebrafish as a potential pharmacological model for screening novel oxime antidotes to organophosphate (OP)-inhibited acetylcholinesterase (AChE). The k{sub i} values determined for chlorpyrifos oxon (CPO) and dichlorvos (DDVP) showed that CPO was a more potent inhibitor of both human and zebrafish AChE, but overall zebrafish AChE was less sensitive to OP inhibition. In contrast, aldoxime antidotes, the quaternary ammonium 2-PAM and tertiary amine RS-194B, showed generally similar overall reactivation kinetics, k{sub r}, in both zebrafish and human AChE. However, differences between the K{sub ox} and k{sub 2} constants suggest that zebrafish AChE associates more tightly with oximes, but has a slower maximal reactivation rate than human AChE. Homology modeling suggests that these kinetic differences result from divergences in the amino acids lining the entrance to the active site gorge. Although 2-PAM had the more favorable in vitro reactivation kinetics, RS-194B was more effective antidote in vivo. In intact zebrafish embryos, antidotal treatment with RS-194B rescued embryos from OP toxicity, whereas 2-PAM had no effect. Dechorionation of the embryos prior to antidotal treatment allowed both 2-PAM and RS-194B to rescue zebrafish embryos from OP toxicity. Interestingly, RS-194B and 2-PAM alone increased cholinergic motor activity in dechorionated embryos possibly due to the reversible inhibition kinetics, K{sub i} and αK{sub i}, of the oximes. Together these results demonstrate that the zebrafish at various developmental stages provides an excellent model for investigating membrane penetrant antidotes to OP exposure. - Highlights: • Zebrafish AChE shares significant structural similarities with human AChE. • OP-inhibited zebrafish and human AChE exhibit similar reactivation kinetics. • The zebrafish chorion is permeable to BBB penetrant and not

  1. Thermodynamic modeling using BINGO-ANTIDOTE: A new strategy to investigate metamorphic rocks

    NASA Astrophysics Data System (ADS)

    Lanari, Pierre; Duesterhoeft, Erik

    2016-04-01

    BINGO-ANTIDOTE is a new program, combing the achievements of the two petrological software packages XMAPTOOLS[1] and THERIAK-DOMINO[2]. XMAPTOOLS affords information about compositional zoning in mineral and local bulk composition of domains at the thin sections scale. THERIAK-DOMINO calculates equilibrium phase assemblages from given bulk rock composition, temperature T and pressure P. Primarily BINGO-ANTIDOTE can be described as an inverse THERIAK-DOMINO, because it uses the information provided by XMAPTOOLS to calculate the probable P-T equilibrium conditions of metamorphic rocks. Consequently, the introduced program combines the strengths of forward Gibbs free energy minimization models with the intuitive output of inverse thermobarometry models. In order to get "best" P-T equilibrium conditions of a metamorphic rock sample and thus estimating the degree of agreement between the observed and calculated mineral assemblage, it is critical to define a reliable scoring strategy. BINGO uses the THERIAKD ADD-ON[3] (Duesterhoeft and de Capitani, 2013) and is a flexible model scorer with 3+1 evaluation criteria. These criteria are the statistical agreement between the observed and calculated mineral-assemblage, -proportions (vol%) and -composition (mol). Additionally, a total likelihood, consisting of the first three criteria, allows the user an evaluation of the most probable equilibrium P-T condition. ANTIDOTE is an interactive user interface, displaying the 3+1 evaluation criteria as probability P-T-maps. It can be used with and without XMAPTOOLS. As a stand-alone program, the user is able to give the program macroscopic observations (i.e., mineral names and proportions), which ANTIDOTE converts to a readable BINGO input. In this manner, the use of BINGO-ANTIDOTE opens up thermodynamics to students and people with only a basic knowledge of phase diagrams and thermodynamic modeling techniques. This presentation introduces BINGO-ANTIDOTE and includes typical examples

  2. Exotic damping ring lattices

    SciTech Connect

    Palmer, R.B.

    1987-05-01

    This paper looks at, and compares three types of damping ring lattices: conventional, wiggler lattice with finite ..cap alpha.., wiggler lattice with ..cap alpha.. = 0, and observes the attainable equilibrium emittances for the three cases assuming a constraint on the attainable longitudinal impedance of 0.2 ohms. The emittance obtained are roughly in the ratio 4:2:1 for these cases.

  3. An antidot array as an edge for total non-reflection of spin waves in yttrium iron garnet films

    SciTech Connect

    Gieniusz, R. Guzowska, U.; Maziewski, A.; Bessonov, V. D.; Stognii, A. I.

    2014-02-24

    An array of antidots has been used as an edge to create the phenomenon of total non-reflection of spin waves in yttrium iron garnet films. At the critical angle between the line of antidots and the magnetic field, we observe a high-intensity beam of spin waves moving along the line of antidots. The properties of these waves are investigated experimentally by Brillouin light scattering spectroscopy. The conditions required for the occurrence of this phenomenon based on an analysis of the properties of the isofrequency dependencies are presented. The numerical simulations are in good agreement with those of the experimental measurements.

  4. 2D superconductivity by ionic gating

    NASA Astrophysics Data System (ADS)

    Iwasa, Yoshi

    2D superconductivity is attracting a renewed interest due to the discoveries of new highly crystalline 2D superconductors in the past decade. Superconductivity at the oxide interfaces triggered by LaAlO3/SrTiO3 has become one of the promising routes for creation of new 2D superconductors. Also, the MBE grown metallic monolayers including FeSe are also offering a new platform of 2D superconductors. In the last two years, there appear a variety of monolayer/bilayer superconductors fabricated by CVD or mechanical exfoliation. Among these, electric field induced superconductivity by electric double layer transistor (EDLT) is a unique platform of 2D superconductivity, because of its ability of high density charge accumulation, and also because of the versatility in terms of materials, stemming from oxides to organics and layered chalcogenides. In this presentation, the following issues of electric filed induced superconductivity will be addressed; (1) Tunable carrier density, (2) Weak pinning, (3) Absence of inversion symmetry. (1) Since the sheet carrier density is quasi-continuously tunable from 0 to the order of 1014 cm-2, one is able to establish an electronic phase diagram of superconductivity, which will be compared with that of bulk superconductors. (2) The thickness of superconductivity can be estimated as 2 - 10 nm, dependent on materials, and is much smaller than the in-plane coherence length. Such a thin but low resistance at normal state results in extremely weak pinning beyond the dirty Boson model in the amorphous metallic films. (3) Due to the electric filed, the inversion symmetry is inherently broken in EDLT. This feature appears in the enhancement of Pauli limit of the upper critical field for the in-plane magnetic fields. In transition metal dichalcogenide with a substantial spin-orbit interactions, we were able to confirm the stabilization of Cooper pair due to its spin-valley locking. This work has been supported by Grant-in-Aid for Specially

  5. Lattice radial quantization: 3D Ising

    NASA Astrophysics Data System (ADS)

    Brower, R. C.; Fleming, G. T.; Neuberger, H.

    2013-04-01

    Lattice radial quantization is introduced as a nonperturbative method intended to numerically solve Euclidean conformal field theories that can be realized as fixed points of known Lagrangians. As an example, we employ a lattice shaped as a cylinder with a 2D Icosahedral cross-section to discretize dilatations in the 3D Ising model. Using the integer spacing of the anomalous dimensions of the first two descendants (l = 1, 2), we obtain an estimate for η = 0.034 (10). We also observed small deviations from integer spacing for the 3rd descendant, which suggests that a further improvement of our radial lattice action will be required to guarantee conformal symmetry at the Wilson-Fisher fixed point in the continuum limit.

  6. Chemical and metabolomic screens identify novel biomarkers and antidotes for cyanide exposure

    PubMed Central

    Nath, Anjali K.; Roberts, Lee D.; Liu, Yan; Mahon, Sari B.; Kim, Sonia; Ryu, Justine H.; Werdich, Andreas; Januzzi, James L.; Boss, Gerry R.; Rockwood, Gary A.; MacRae, Calum A.; Brenner, Matthew; Gerszten, Robert E.; Peterson, Randall T.

    2013-01-01

    Exposure to cyanide causes a spectrum of cardiac, neurological, and metabolic dysfunctions that can be fatal. Improved cyanide antidotes are needed, but the ideal biological pathways to target are not known. To understand better the metabolic effects of cyanide and to discover novel cyanide antidotes, we developed a zebrafish model of cyanide exposure and scaled it for high-throughput chemical screening. In a screen of 3120 small molecules, we discovered 4 novel antidotes that block cyanide toxicity. The most potent antidote was riboflavin. Metabolomic profiling of cyanide-treated zebrafish revealed changes in bile acid and purine metabolism, most notably by an increase in inosine levels. Riboflavin normalizes many of the cyanide-induced neurological and metabolic perturbations in zebrafish. The metabolic effects of cyanide observed in zebrafish were conserved in a rabbit model of cyanide toxicity. Further, humans treated with nitroprusside, a drug that releases nitric oxide and cyanide ions, display increased circulating bile acids and inosine. In summary, riboflavin may be a novel treatment for cyanide toxicity and prophylactic measure during nitroprusside treatment, inosine may serve as a biomarker of cyanide exposure, and metabolites in the bile acid and purine metabolism pathways may shed light on the pathways critical to reversing cyanide toxicity.—Nath, A. K., Roberts, L. D., Liu, Y., Mahon, S. B., Kim, S., Ryu, J. H., Werdich, A., Januzzi, J. L., Boss, G. R., Rockwood, G. A., MacRae, C. A., Brenner, M., Gerszten, R. E., Peterson, R. T. Chemical and metabolomic screens identify novel biomarkers and antidotes for cyanide exposure. PMID:23345455

  7. Mechanical properties of lattice grid composites

    NASA Astrophysics Data System (ADS)

    Fan, Hualin; Fang, Daining; Jin, Fengnian

    2008-08-01

    An equivalent continuum method only considering the stretching deformation of struts was used to study the in-plane stiffness and strength of planar lattice grid composite materials. The initial yield equations of lattices were deduced. Initial yield surfaces were depicted separately in different 3D and 2D stress spaces. The failure envelope is a polyhedron in 3D spaces and a polygon in 2D spaces. Each plane or line of the failure envelope is corresponding to the yield or buckling of a typical bar row. For lattices with more than three bar rows, subsequent yield of the other bar row after initial yield made the lattice achieve greater limit strength. The importance of the buckling strength of the grids was strengthened while the grids were relative sparse. The integration model of the method was used to study the nonlinear mechanical properties of strain hardening grids. It was shown that the integration equation could accurately model the complete stress-strain curves of the grids within small deformations.

  8. Lattice expansion of highly oriented 2D phthalocyanine covalent organic framework films.

    PubMed

    Spitler, Eric L; Colson, John W; Uribe-Romo, Fernando J; Woll, Arthur R; Giovino, Marissa R; Saldivar, Abraham; Dichtel, William R

    2012-03-12

    Expanding into application: covalent organic framework (COF) films are ideally suited for vertical charge transport and serve as precursors of ordered heterojunctions. Their pores, however, were previously too small to accommodate continuous networks of complementary electron acceptors. Four phthalocyanine COFs with increased pore size well into the mesoporous regime are now described.

  9. A 2D Rods-in-Air Square-Lattice Photonic Crystal Optical Switch

    DTIC Science & Technology

    2009-03-01

    bistable switching in nonlinear photonic crystals, Phys. Rev. E. 66 (5) (2002) 055601(R). [14] Mehmet Fatih Yanik , Shanhui Fan, Marin Soljačić, High...1855–1857. [19] Mehmet Fatih Yanik , Shanhui Fan, Marin Soljačić, J.D. Joannopoulos, All- optical transistor action with bistable switching in a

  10. Two-dimensional lattice model for the surface states of topological insulators

    NASA Astrophysics Data System (ADS)

    Zhou, Yan-Feng; Jiang, Hua; Xie, X. C.; Sun, Qing-Feng

    2017-06-01

    The surface states in three-dimensional (3D) topological insulators can be described by a two-dimensional (2D) continuous Dirac Hamiltonian. However, there exists the fermion doubling problem when putting the continuous 2D Dirac equation into a lattice model. In this paper, we introduce a Wilson term with a zero bare mass into the 2D lattice model to overcome the difficulty. By comparing with a 3D Hamiltonian, we show that the modified 2D lattice model can faithfully describe the low-energy electrical and transport properties of surface states of 3D topological insulators. So this 2D lattice model provides a simple and cheap way to numerically simulate the surface states of 3D topological-insulator nanostructures. Based on the 2D lattice model, we also establish the wormhole effect in a topological-insulator nanowire by a magnetic field along the wire and show the surface states being robust against disorder. The proposed 2D lattice model can be extensively applied to study the various properties and effects, such as the transport properties, Hall effect, universal conductance fluctuations, localization effect, etc. So, it paves a way to study the surface states of the 3D topological insulators.

  11. 2D non-separable linear canonical transform (2D-NS-LCT) based cryptography

    NASA Astrophysics Data System (ADS)

    Zhao, Liang; Muniraj, Inbarasan; Healy, John J.; Malallah, Ra'ed; Cui, Xiao-Guang; Ryle, James P.; Sheridan, John T.

    2017-05-01

    The 2D non-separable linear canonical transform (2D-NS-LCT) can describe a variety of paraxial optical systems. Digital algorithms to numerically evaluate the 2D-NS-LCTs are not only important in modeling the light field propagations but also of interest in various signal processing based applications, for instance optical encryption. Therefore, in this paper, for the first time, a 2D-NS-LCT based optical Double-random- Phase-Encryption (DRPE) system is proposed which offers encrypting information in multiple degrees of freedom. Compared with the traditional systems, i.e. (i) Fourier transform (FT); (ii) Fresnel transform (FST); (iii) Fractional Fourier transform (FRT); and (iv) Linear Canonical transform (LCT), based DRPE systems, the proposed system is more secure and robust as it encrypts the data with more degrees of freedom with an augmented key-space.

  12. Cooperative dynamics in ultrasoft 2D crystals

    NASA Astrophysics Data System (ADS)

    Sprakel, Joris; van der Meer, Berend; Dijkstra, Marjolein; van der Gucht, Jasper

    2015-03-01

    The creation, annihilation, and diffusion of defects in crystal lattices play an important role during crystal melting and deformation. Although it is well understood how defects form and react when crystals are subjected to external stresses, it remains unclear how crystals cope with internal stresses. We report a study in which we create a highly localized internal stress, by means of optical tweezing, in a crystal formed from micrometer-sized colloidal spheres and directly observe how the solid reacts using microscopy. We find that, even though the excitation is highly localized, a collective dance of colloidal particles results; these collective modes take the form of closed rings or open-ended strings, depending on the sequence of events which nucleate the rearrangements. Surprisingly, we find from Brownian Dynamics simulations that these cooperative dynamics are thermally-activated modes inherent to the crystal, and can even occur through a single, sufficiently large thermal fluctuation, resulting in the irreversible displacement of 100s of particles from their lattice sites.

  13. Phase diagram of split 2D dipolar spin ice

    NASA Astrophysics Data System (ADS)

    Roscilde, Tommaso; Henry, Louis-Paul

    2013-03-01

    Long-ranged dipolar interactions, which are very natural in artificial square-lattice spin ice, can mask some of the most relevant aspects of spin-ice physics, as they remove the extensive degeneracy of the ground state manifold to give a unique ground state, and they bind monopole pairs into localized spin flips. Following an earlier idea of G. Möller and R. Moessner [Phys. Rev. Lett. 96, 237202 (2006)] we investigate how adding a third direction to square ice allows to recover fundamental traits of spin-ice physics even in the presence of dipolar interactions. Using Monte Carlo simulations based on a generalized loop algorithm, we explore the phase diagram of square dipolar spin ice in which horizontal and vertical dipoles are spatially separated in a third direction (split 2D spin ice). As a function of the splitting we recover a two-fold degenerate staggered state for coplanar dipoles, and a four-fold degenerate ``Manhattan'' state for strongly split dipoles, separated by a first order transition. The competition between the two states at intermediate splitting leads to a strong suppression of the ordering transition temperatures, and makes space for the observation of a hallmark of spin-ice physics in the paramagnetic phase: pinch points in the static structure factor.

  14. Codon Constraints on Closed 2D Shapes,

    DTIC Science & Technology

    2014-09-26

    19843$ CODON CONSTRAINTS ON CLOSED 2D SHAPES Go Whitman Richards "I Donald D. Hoffman’ D T 18 Abstract: Codons are simple primitives for describing plane...RSONAL AUT"ORtIS) Richards, Whitman & Hoffman, Donald D. 13&. TYPE OF REPORT 13b. TIME COVERED N/A P8 AT F RRrT t~r. Ago..D,) is, PlE COUNT Reprint...outlines, if figure and ground are ignored. Later, we will address the problem of indexing identical codon descriptors that have different figure

  15. ENERGY LANDSCAPE OF 2D FLUID FORMS

    SciTech Connect

    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.

  16. Periodically sheared 2D Yukawa systems

    SciTech Connect

    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.

  17. A novel antidote-controlled anticoagulant reduces thrombin generation and inflammation and improves cardiac function in cardiopulmonary bypass surgery.

    PubMed

    Nimjee, Shahid M; Keys, J R; Pitoc, G A; Quick, G; Rusconi, C P; Sullenger, Bruce A

    2006-09-01

    Heparin and protamine are the standard anticoagulant-antidote regimen used in almost every cardiopulmonary bypass (CPB) procedure even though both are associated with an array of complications and toxicities. Here we demonstrate that an anticoagulant aptamer-antidote pair targeting factor IXa can replace heparin and protamine in a porcine CPB model and also limit the adverse effects on thrombin generation, inflammation, and cardiac physiology associated with heparin and protamine use. These results demonstrate that targeting clotting factors upstream of thrombin in the coagulation cascade can potentially reduce the perioperative pathologies associated with CPB and suggest that the aptamer-antidote pair to FIXa may improve the outcome of patients undergoing CPB. In particular, this novel anticoagulant-antidote pair may prove to be useful in patients diagnosed with heparin-induced thrombocytopenia or those who have been sensitized to protamine, particularly patients who have insulin-dependent diabetes.

  18. Effect of antiferromagnetic layer thickness on exchange bias, training effect, and magnetotransport properties in ferromagnetic/antiferromagnetic antidot arrays

    SciTech Connect

    Gong, W. J.; Liu, W. Feng, J. N.; Zhang, Z. D.; Kim, D. S.; Choi, C. J.

    2014-04-07

    The effect of antiferromagnetic (AFM) layer on exchange bias (EB), training effect, and magnetotransport properties in ferromagnetic (FM) /AFM nanoscale antidot arrays and sheet films Ag(10 nm)/Co(8 nm)/NiO(t{sub NiO})/Ag(5 nm) at 10 K is studied. The AFM layer thickness dependence of the EB field shows a peak at t{sub NiO} = 2 nm that is explained by using the random field model. The misalignment of magnetic moments in the three-dimensional antidot arrays causes smaller decrease of EB field compared with that in the sheet films for training effect. The anomalous magnetotransport properties, in particular positive magnetoresistance (MR) for antidot arrays but negative MR for sheet films are found. The training effect and magnetotransport properties are strongly affected by the three-dimensional spin-alignment effects in the antidot arrays.

  19. Recovery from ultra-high dose organophosphate poisoning after "in-the-field" antidote treatment: potential lessons for civil defense.

    PubMed

    Schrickel, Jan Wilko; Lewalter, Thorsten; Lüderitz, Berndt; Nickenig, Georg; Klehr, Hans-Ulrich; Rabe, Christian

    2009-10-01

    Organophosphate poisoning is associated with a high mortality rate due to respiratory failure, dysrhythmias, and multi-organ failure. We report two cases of survival after "in-the field" antidote treatment of very severe organophosphate poisonings. Two patients orally ingested large amounts of the organophosphorous agent oxydemeton-methyl in suicide attempts, resulting in the hypercholinergic syndrome in both. Resuscitation included early administration of antidote by emergency medical personnel as well as high-dose atropine. Plasma levels of pseudo cholinesterase were initially very low in both patients. Long-term mechanical ventilation was necessary, and both patients developed aspiration pneumonia. At discharge, no major neurological deficits were present. Prompt antidote treatment and aggressive supportive emergency and intensive care unit therapy contribute to improved survival after acute organophosphate poisoning. We believe that in cases of mass poisonings--for example, terrorist activity--therapy must be available on the scene as soon as possible. This also may require decentralized antidote storage.

  20. Remarks on thermalization in 2D CFT

    NASA Astrophysics Data System (ADS)

    de Boer, Jan; Engelhardt, Dalit

    2016-12-01

    We revisit certain aspects of thermalization in 2D conformal field theory (CFT). In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a Banados-Teitelboim-Zanelli black hole. The extra conserved charges, while rendering c <1 theories essentially integrable, therefore seem to have little effect on large-c conformal field theories.

  1. Gas sensing in 2D materials

    NASA Astrophysics Data System (ADS)

    Yang, Shengxue; Jiang, Chengbao; Wei, Su-huai

    2017-06-01

    Two-dimensional (2D) layered inorganic nanomaterials have attracted huge attention due to their unique electronic structures, as well as extraordinary physical and chemical properties for use in electronics, optoelectronics, spintronics, catalysts, energy generation and storage, and chemical sensors. Graphene and related layered inorganic analogues have shown great potential for gas-sensing applications because of their large specific surface areas and strong surface activities. This review aims to discuss the latest advancements in the 2D layered inorganic materials for gas sensors. We first elaborate the gas-sensing mechanisms and introduce various types of gas-sensing devices. Then, we describe the basic parameters and influence factors of the gas sensors to further enhance their performance. Moreover, we systematically present the current gas-sensing applications based on graphene, graphene oxide (GO), reduced graphene oxide (rGO), functionalized GO or rGO, transition metal dichalcogenides, layered III-VI semiconductors, layered metal oxides, phosphorene, hexagonal boron nitride, etc. Finally, we conclude the future prospects of these layered inorganic materials in gas-sensing applications.

  2. 2D packing using the Myriad framework

    NASA Astrophysics Data System (ADS)

    Chatburn, Luke T.; Batchelor, Bruce G.

    2004-02-01

    Myriad is a framework for building networked and distributed vision systems and is described in a companion paper in this conference. Myriad allows the components of a multi-camera, multi-user vision system (web-cameras, image processing engines, intelligent device controllers, databases and the user interface terminals) to be interconnected and operated together, even if they are physically separated by many hundreds, or thousands, of kilometres. This is achieved by operating them as Internet services. The principal objective in this article is to illustrate the simplicity of harmonising visual control with an existing system using Myriad. However, packing of 2-dimensional blob-like objects is of considerable commercial importance in some industries and involves robotic handling and/or cutting. The shapes to be packed may be cut from sheet metal, glass, cloth, leather, wood, card, paper, composite board, or flat food materials. In addition, many 3D packing applications can realistically be tackled only by regarding them as multi-layer 2D applications. Using Myriad to perform 2D packing, a set of blob-like input objects ("shapes") can be digitised using a standard camera (e.g. a "webcam"). The resulting digital images are then analysed, using a separate processing engine, perhaps located on a different continent. The packing is planned by another processing system, perhaps on a third continent. Finally, the assembly is performed using a robot, usually but not necessarily, located close to the camera.

  3. 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.

  4. Majorana fermions in vortex lattices

    NASA Astrophysics Data System (ADS)

    Biswas, Rudro

    2013-03-01

    We consider Majorana fermions tunneling between vortices, within an array of such vortices in a 2D chiral p-wave superconductor. We calculate that the tunneling amplitude for Majorana fermions in a pair of vortices is proportional to the sine of half the difference between the global order parameter phases at the two vortices. Using this result we study tight-binding models of Majorana fermions in vortices arranged in a triangular or square lattice. In both cases we find that this phase-tunneling relationship leads to the creation of superlattices where the Majorana fermions form macroscopically degenerate `flat' bands at zero energy, in addition to other dispersive bands. This finding suggests that in vortex arrays tunneling processes do not change the energies of a finite fraction of Majorana fermions and hence brighten the prospects of topological quantum computing with a large number of Majorana states.

  5. 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.

  6. Biomedical effects of chemical-threat-agent antidote and pretreatment drugs. An abstracted bibliography. Volume 1. Interim report

    SciTech Connect

    Lentz, J.M.; Reams, G.G.; DeJohn, C.A.

    1986-04-01

    The bibliographic abstracts in this report are part of a project to assess biomedical effects of chemical-warfare antidote agents and related pre-treatment drugs. Specific attention is focused on the biomedical effects in the following general areas: vision, auditory, spatial orientation, musculoskeletal, cardipulmonary, cognitive performance, pharmacology, cutaneous stimuli, and cortical effects. In some cases, the bibliography addresses other therapeutic drugs that may be used simultaneously with chemical-warfare antidotes.

  7. Pearcey solitons in curved nonlinear photonic caustic lattices

    NASA Astrophysics Data System (ADS)

    Zannotti, A.; Rüschenbaum, M.; Denz, C.

    2017-09-01

    Controlling artificial Pearcey and swallowtail beams allows the realization of caustic lattices in nonlinear photosensitive media at very low light intensities. We examine their functionality as 2D and 3D waveguiding structures and show the potential of exploiting these lattices as linear beam splitters, which we name a ‘Pearcey-Y-splitter’. For symmetrized Pearcey beams as auto-focusing beams, the formation of solitons in focusing nonlinearity is observed. Our original approach represents the first realization of caustic photonic lattices and can directly be applied in signal processing, microscopy and material lithography.

  8. 2-D or not 2-D, that is the question: A Northern California test

    SciTech Connect

    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

  9. Patterns of cyanide antidote use since regulatory approval of hydroxocobalamin in the United States.

    PubMed

    Streitz, Matthew J; Bebarta, Vikhyat S; Borys, Douglas J; Morgan, David L

    2014-01-01

    Sodium nitrite and sodium thiosulfate are common cyanide antidotes. Hydroxocobalamin was approved for use in the United States in 2006. Our objective was to determine the frequency of antidote use as reported to the US poison centers from 2005 to 2009 and describe which antidotes were used in critically ill cyanide toxic patients. We performed a retrospective review over 5 years (2005-2009) from 61 US poison centers. We identified all cyanide-exposed cases that received a cyanide antidote. Variables collected included demographics, gastric decontamination, antidote used, predefined serious clinical effects (hypotension, cardiac arrest, respiratory arrest, and coma), and predefined serious therapies (cardiopulmonary resuscitation, vasopressors, atropine, anticonvulsant, antidysrhythmic, and intubation/ventilation). One trained abstractor abstracted each chart to a standardized electronic form. Another investigator audited 20% of the charts. Kappa values were calculated. One hundred sixty-five exposures were identified. Mean age was 42 years (range, 3-93 years). Seventy-one percent were male. Exposures were 27% ingestion and 53% inhalation. Thirty-two percent of the ingestions were suicide attempts. Twenty percent (32 of 157) of all cases died. Over all years reported, hydroxocobalamin was administered to 29% (45 of 157) of patients, sodium nitrite to 25%, and sodium thiosulfate to 46%. Hydroxocobalamin use increased from 24% to 54% from 2007 to 2009, respectively (P = 0.024). Sodium thiosulfate use decreased from 73% to 31% (P = 0.002) and sodium nitrite use decreased from 26% to 14% (P = 0.39). The proportion of cases with serious clinical effects that received hydroxocobalamin increased each year, and the proportion that received other antidotes decreased. Hydroxocobalamin was also administered more often in cases that required serious therapies and increased each year. Hydroxocobalamin use for cyanide toxicity increased each year as reported to the US poison

  10. Calculating excitons, plasmons, and quasiparticles in 2D materials and van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Sommer Thygesen, Kristian

    2017-06-01

    Atomically thin two-dimensional (2D) materials host a rich set of electronic states that differ substantially from those of their bulk counterparts due to quantum confinement and enhanced many-body effects. This Topical Review focuses on the theory and computation of excitons, plasmons and quasiparticle band structures in 2D materials and their heterostructures. The general theory is illustrated by applications to various types of 2D materials including transition metal dichalcogenides, graphene, phosphorene, and hexagonal boron nitride. The weak and highly non-local dielectric function of atomically thin crystals is shown to be responsible for many of the unique properties exhibited by the 2D materials such as the formation of strongly bound, non-Hydrogenic excitons, large band gap renormalization effects, and the different signatures of excitons and plasmons in electron energy loss spectroscopy (EELS). Among other topics covered are spin-orbit coupling, trions, interlayer excitons, exciton dissociation, and environmental screening. Technical issues associated with the application of the many-body GW method and the Bethe-Salpeter equation (BSE) to 2D materials are also discussed. A combined quantum/classical method is introduced and used throughout to account for dielectric screening and self-energy effects from substrates and van der Waals heterostructures including the difficult case of non-matching lattices.

  11. Incommensurate lattice modulations in Potassium Vanadate

    NASA Astrophysics Data System (ADS)

    Chakoumakos, Bryan; Banerjee, Arnab; Mark, Lumsden; Cao, Huibo; Kim, Jong-Woo; Hoffman, Christina; Wang, Xiaoping

    Potassium Vanadate (K2V3O8) is an S = 1/2 2D square lattice antiferromagnet that shows spin reorientation indicating a strong coupling between the magnetism and its dielectric properties with a promise of rich physics that promises multiferroicity. These tangible physical properties are strongly tied through a spin-lattice coupling to the underlying lattice and superlattice behavior. It has a superlattice (SL) onsetting below Tc = 115 K with an approximate [3 x 3 x 2] modulation. Here we present our recent experiments at TOPAZ beamline at SNS which for the first time proves conclusively that the lattice modulations are incommensurate, with an in-plane Q of 0.315. We will also show our attempts to refine the data using JANA which requires a redefinition of the lattice, as well as the temperature and Q dependence of the superlattice modulation measured using neutrons at HFIR and synchrotron x-rays at APS. Our results are not only relevant for the ongoing search of multifunctional behavior in K2V3O8 but also generally for the superlattice modulations observed in a large family of fresnoites. Work performed at ORNL and ANL is supported by U.S. Dept. of Energy, Office of Basic Energy Sciences and Office of User Facilities Division.

  12. Some properties of correlations of quantum lattice systems in thermal equilibrium

    SciTech Connect

    Fröhlich, Jürg; Ueltschi, Daniel

    2015-05-15

    Simple proofs of uniqueness of the thermodynamic limit of KMS states and of the decay of equilibrium correlations are presented for a large class of quantum lattice systems at high temperatures. New quantum correlation inequalities for general Heisenberg models are described. Finally, a simplified derivation of a general result on power-law decay of correlations in 2D quantum lattice systems with continuous symmetries is given, extending results of McBryan and Spencer for the 2D classical XY model.

  13. Designing an artificial Lieb lattice on a metal surface

    NASA Astrophysics Data System (ADS)

    Qiu, Wen-Xuan; Li, Shuai; Gao, Jin-Hua; Zhou, Yi; Zhang, Fu-Chun

    2016-12-01

    Recently, several experiments [K. K. Gomes et al., Nature (London) 483, 306 (2012), 10.1038/nature10941; S. Wang et al., Phys. Rev. Lett. 113, 196803 (2014), 10.1103/PhysRevLett.113.196803] have illustrated that metal surface electrons can be manipulated to form a two-dimensional (2D) lattice by depositing a designer molecule lattice on a metal surface. This offers a promising new technique to construct artificial 2D electron lattices. Here we theoretically propose a molecule lattice pattern to realize an artificial Lieb lattice on a metal surface, which shows a flat electronic band due to the lattice geometry. We show that the localization of electrons in the flat band may be understood from the viewpoint of electron interference, which may be probed by measuring the local density of states with scanning tunneling microscopy. Our proposal may be readily implemented in experiment and may offer an ideal solid state platform to investigate the novel flat band physics of the Lieb lattice.

  14. Lattice invariants for knots

    SciTech Connect

    Janse Van Rensburg, E.J.

    1996-12-31

    The geometry of polygonal knots in the cubic lattice may be used to define some knot invariants. One such invariant is the minimal edge number, which is the minimum number of edges necessary (and sufficient) to construct a lattice knot of given type. In addition, one may also define the minimal (unfolded) surface number, and the minimal (unfolded) boundary number; these are the minimum number of 2-cells necessary to construct an unfolded lattice Seifert surface of a given knot type in the lattice, and the minimum number of edges necessary in a lattice knot to guarantee the existence of an unfolded lattice Seifert surface. In addition, I derive some relations amongst these invariants. 8 refs., 5 figs., 2 tabs.

  15. Simulation of Yeast Cooperation in 2D.

    PubMed

    Wang, M; Huang, Y; Wu, Z

    2016-03-01

    Evolution of cooperation has been an active research area in evolutionary biology in decades. An important type of cooperation is developed from group selection, when individuals form spatial groups to prevent them from foreign invasions. In this paper, we study the evolution of cooperation in a mixed population of cooperating and cheating yeast strains in 2D with the interactions among the yeast cells restricted to their small neighborhoods. We conduct a computer simulation based on a game theoretic model and show that cooperation is increased when the interactions are spatially restricted, whether the game is of a prisoner's dilemma, snow drifting, or mutual benefit type. We study the evolution of homogeneous groups of cooperators or cheaters and describe the conditions for them to sustain or expand in an opponent population. We show that under certain spatial restrictions, cooperator groups are able to sustain and expand as group sizes become large, while cheater groups fail to expand and keep them from collapse.

  16. Variational regularized 2-D nonnegative matrix factorization.

    PubMed

    Gao, Bin; Woo, W L; Dlay, S S

    2012-05-01

    A novel approach for adaptive regularization of 2-D nonnegative matrix factorization is presented. The proposed matrix factorization is developed under the framework of maximum a posteriori probability and is adaptively fine-tuned using the variational approach. The method enables: (1) a generalized criterion for variable sparseness to be imposed onto the solution; and (2) prior information to be explicitly incorporated into the basis features. The method is computationally efficient and has been demonstrated on two applications, that is, extracting features from image and separating single channel source mixture. In addition, it is shown that the basis features of an information-bearing matrix can be extracted more efficiently using the proposed regularized priors. Experimental tests have been rigorously conducted to verify the efficacy of the proposed method.

  17. 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).

  18. 2D quantum gravity from quantum entanglement.

    PubMed

    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.

  19. 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.

  20. 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.

  1. Transition to turbulence: 2D directed percolation

    NASA Astrophysics Data System (ADS)

    Chantry, Matthew; Tuckerman, Laurette; Barkley, Dwight

    2016-11-01

    The transition to turbulence in simple shear flows has been studied for well over a century, yet in the last few years has seen major leaps forward. In pipe flow, this transition shows the hallmarks of (1 + 1) D directed percolation, a universality class of continuous phase transitions. In spanwisely confined Taylor-Couette flow the same class is found, suggesting the phenomenon is generic to shear flows. However in plane Couette flow the largest simulations and experiments to-date find evidence for a discrete transition. Here we study a planar shear flow, called Waleffe flow, devoid of walls yet showing the fundamentals of planar transition to turbulence. Working with a quasi-2D yet Navier-Stokes derived model of this flow we are able to attack the (2 + 1) D transition problem. Going beyond the system sizes previously possible we find all of the required scalings of directed percolation and thus establish planar shears flow in this class.

  2. Jamming in 2D Prolate Granular Materials

    NASA Astrophysics Data System (ADS)

    Franklin, Scott

    2003-11-01

    We have been looking at how 2D piles of prolate (L/D>1) granular materials respond when disturbed. A test object is pushed slowly through a horizontal network of particles; the packing fraction and particle aspect ratio can be varied independently. Particles are cut from square brass rods; the square cross-section reduces the chances of a particle rolling on top of another and keeps the pile two-dimensinal. The initial condition of the pile is quantified with an orientational order parameter which measures the inter-particle alignment. At a critical packing fraction the pile jams and the force needed to push the test object through the pile increases. The jammed state also corresponds to an increase in the number of particles undergoing large-scale motion. This is revealed both in video analysis, which measures particle rearrangments within the pile, and in the number of particles that are pushed off the end of the table.

  3. 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.

  4. 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.

  5. Numerical Evaluation of 2D Ground States

    NASA Astrophysics Data System (ADS)

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  6. The EMMA Lattice

    NASA Astrophysics Data System (ADS)

    Berg, J. Scott

    2008-02-01

    EMMA is a 10 to 20 MeV electron ring designed to test our understanding of beam dynamics in a relativistic linear non-scaling fixed field alternating gradient accelerator (FFAG). I will give a basic review of the EMMA lattice parameters. Then I will review the different lattice configurations that we would like to have for EMMA. Finally, I will briefly discuss the process of commissioning each lattice configuration.

  7. A lattice-Boltzmann scheme of the Navier-Stokes equations on a 3D cuboid lattice

    NASA Astrophysics Data System (ADS)

    Min, Haoda; Peng, Cheng; Wang, Lian-Ping

    2015-11-01

    The standard lattice-Boltzmann method (LBM) for fluid flow simulation is based on a square (in 2D) or cubic (in 3D) lattice grids. Recently, two new lattice Boltzmann schemes have been developed on a 2D rectangular grid using the MRT (multiple-relaxation-time) collision model, by adding a free parameter in the definition of moments or by extending the equilibrium moments. Here we developed a lattice Boltzmann model on 3D cuboid lattice, namely, a lattice grid with different grid lengths in different spatial directions. We designed our MRT-LBM model by matching the moment equations from the Chapman-Enskog expansion with the Navier-Stokes equations. The model guarantees correct hydrodynamics. A second-order term is added to the equilibrium moments in order to restore the isotropy of viscosity on a cuboid lattice. The form and the coefficients of the extended equilibrium moments are determined through an inverse design process. An additional benefit of the model is that the viscosity can be adjusted independent of the stress-moment relaxation parameter, thus improving the numerical stability of the model. The resulting cuboid MRT-LBM model is then validated through benchmark simulations using laminar channel flow, turbulent channel flow, and the 3D Taylor-Green vortex flow.

  8. LatticeLibrary and BccFccRaycaster: Software for processing and viewing 3D data on optimal sampling lattices

    NASA Astrophysics Data System (ADS)

    Linnér, Elisabeth Schold; Morén, Max; Smed, Karl-Oskar; Nysjö, Johan; Strand, Robin

    In this paper, we present LatticeLibrary, a C++ library for general processing of 2D and 3D images sampled on arbitrary lattices. The current implementation supports the Cartesian Cubic (CC), Body-Centered Cubic (BCC) and Face-Centered Cubic (FCC) lattices, and is designed to facilitate addition of other sampling lattices. We also introduce BccFccRaycaster, a plugin for the existing volume renderer Voreen, making it possible to view CC, BCC and FCC data, using different interpolation methods, with the same application. The plugin supports nearest neighbor and trilinear interpolation at interactive frame rates. These tools will enable further studies of the possible advantages of non-Cartesian lattices in a wide range of research areas.

  9. Lighten the Olympia of the Flatland: Probing and Manipulating the Photonic Properties of 2D Transition-Metal Dichalcogenides.

    PubMed

    Zhou, Kai-Ge; Zhang, Hao-Li

    2015-07-15

    Following the adventures of graphene, 2D transition metal dichalcogenides (TMDs) have recently seized part of the territory in the flatland. Branched by different components of metals and chalcogenides, the families of 2D TMDs have grown rapidly, in which the semiconductive ones have shown colorful photonic properties. By tuning the atomic components and reducing the thickness or planar size of the layers, one can manipulate the optical performance of 2D TMDs, e.g., the intensity, angular momentum, and frequency of the emitted light, or toward ultrafast nonlinear absorption. As a powerful optical method, the Raman characteristics of 2D TMDs have been successfully used to explore their lattices and electronic structures. Along with the maturing of 2D TMDs, their hybrids play an important role. The unique photonic properties of 2D van der Waals heterostructures and 2D alloys are introduced here. Apart from the group VI TMDs, future prospects are identified to harness the optical properties of other 2D TMDs and the related investigations of their hybrids are underway.

  10. The mouse ruby-eye 2(d) (ru2(d) /Hps5(ru2-d) ) allele inhibits eumelanin but not pheomelanin synthesis.

    PubMed

    Hirobe, Tomohisa; Ito, Shosuke; Wakamatsu, Kazumasa

    2013-09-01

    The novel mutation named ru2(d) /Hps5(ru2-d) , characterized by light-colored coats and ruby-eyes, prohibits differentiation of melanocytes by inhibiting tyrosinase (Tyr) activity, expression of Tyr, Tyr-related protein 1 (Tyrp1), Tyrp2, and Kit. However, it is not known whether the ru2(d) allele affects pheomelanin synthesis in recessive yellow (e/Mc1r(e) ) or in pheomelanic stage in agouti (A) mice. In this study, effects of the ru2(d) allele on pheomelanin synthesis were investigated by chemical analysis of melanin present in dorsal hairs of 5-week-old mice from F2 generation between C57BL/10JHir (B10)-co-isogenic ruby-eye 2(d) and B10-congenic recessive yellow or agouti. Eumelanin content was decreased in ruby-eye 2(d) and ruby-eye 2(d) agouti mice, whereas pheomelanin content in ruby-eye 2(d) recessive yellow and ruby-eye 2(d) agouti mice did not differ from the corresponding Ru2(d) /- mice, suggesting that the ru2(d) allele inhibits eumelanin but not pheomelanin synthesis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Antidotes to coumarins, isoniazid, methotrexate and thyroxine, toxins that work via metabolic processes.

    PubMed

    Bateman, D Nicholas; Page, Colin B

    2016-03-01

    Some toxins cause their effects by affecting physiological processes that are fundamental to cell function or cause systemic effects as a result of cellular interaction. This review focuses on four examples, coumarin anticoagulants, isoniazid, methotrexate and thyroxine from the context of management of overdose as seen in acute general hospitals. The current basic clinical pharmacology of the toxin, the clinical features in overdose and evidence base for specific antidotes are discussed. The treatment for this group is based on an understanding of the toxic mechanism, but studies to determine the optimum dose of antidote are still required in all these toxins except thyroxine, where treatment dose is based on symptoms resulting from the overdose.

  12. The bezoar stone: a princely antidote, the Távora Sequeira Pinto Collection-Oporto.

    PubMed

    Do Sameiro Barroso, Maria

    2014-01-01

    Bezoar stones, once used as universal antidotes and panaceas, but currently regarded as costly and useless medicines of the past, are a major milestone in the history of toxicology. Arabic physicians had been using bezoars in medicine from the 8th century onwards. In the 16th century, the Portuguese controlled bezoar trade from India, and the Portuguese doctors Garcia de Orta, Amatus Lusitanus, and Cristobal Acosta introduced the medicinal use of Oriental bezoars to European medical literature. Some criticism aside, leading European doctors prescribed bezoars mainly as powerful antidotes. Five bezoars that now adorn the Távora Sequeira Pinto Collection in Oporto testify to the allure and glory of bezoars at the height of their golden age, when they equalled the splendour of gems and noble minerals that dominated the Eastern and Western lithotherapy.The end of the 18th century marked the end of ancient panaceas. This article focuses on the therapeutic and apotropaic use of bezoars.

  13. Quantum Hall effect in semiconductor systems with quantum dots and antidots

    SciTech Connect

    Beltukov, Ya. M.; Greshnov, A. A.

    2015-04-15

    The integer quantum Hall effect in systems of semiconductor quantum dots and antidots is studied theoretically as a factor of temperature. It is established that the conditions for carrier localization in quantum-dot systems favor the observation of the quantum Hall effect at higher temperatures than in quantum-well systems. The obtained numerical results show that the fundamental plateau corresponding to the transition between the ground and first excited Landau levels can be retained up to a temperature of T ∼ 50 K, which is an order of magnitude higher than in the case of quantum wells. Implementation of the quantum Hall effect at such temperatures requires quantum-dot systems with controllable characteristics, including the optimal size and concentration and moderate geometrical and composition fluctuations. In addition, ordered arrangement is desirable, hence quantum antidots are preferable.

  14. Liquid chromatographic determination of atropine in nerve gas antidotes and other dosage forms.

    PubMed

    Lehr, G J; Yuen, S M; Lawrence, G D

    1995-01-01

    A simple and specific liquid chromatographic method was developed for the determination of atropine in nerve gas antidotes and several other dosage forms. The method is also used simultaneously to quantitate phenol, an antimicrobial agent present in nerve gas antidotes, and to monitor the level of tropic acid, a principal degradation product of atropine. The system uses a Spherisorb CN column and a mobile phase of acetonitrile-0.05M sodium phosphate monobasic (10 + 90), pH 4.0. The detection wavelength is 220 nm. The method was validated by testing for accuracy, linearity, reproducibility and precision. In addition, the proposed method was applied to 8 commercial preparations of atropine, including injectables, ophthalmic solutions, and ointments, and was found to be satisfactory and free from interferences from preservatives, such as benzyl alcohol, methylparaben, benzalkonium chloride and chlorobutanol, that are present in these formulations.

  15. Oral anticoagulants and status of antidotes for the reversal of bleeding risk.

    PubMed

    Ebright, Joseph; Mousa, Shaker A

    2015-03-01

    Anticoagulants have been used in clinical practice for more than 50 years. Their indications expand, as more people are diagnosed each year with atrial fibrillation and venous thromboembolism. Vitamin K antagonists have been the most popular choice due to their effectiveness and their ability to reverse bleeding using a known antidote; oral and intravenous vitamin K have long been known to reverse the effects of warfarin. With new classes of anticoagulants making their way onto the market, such as factor Xa inhibitors (rivaroxaban, apixaban) and direct thrombin inhibitors (dabigatran), the need for new reversal agents is paramount. Patients tend to be more receptive to these medications because they do not require routine blood monitoring, can be used at fixed doses, and do not have major drug or food interactions. Antidotes for these medications have shown promise in animal models and are currently in clinical trials.

  16. Antidote treatment for cyanide poisoning with hydroxocobalamin causes bright pink discolouration and chemical-analytical interferences.

    PubMed

    Brunel, C; Widmer, C; Augsburger, M; Dussy, F; Fracasso, T

    2012-11-30

    Here we report the case of a 70-year-old woman who committed suicide by cyanide poisoning. During resuscitation cares, she underwent an antidote treatment by hydroxocobalamin. Postmortem investigations showed marked bright pink discolouration of organs and fluids, and a lethal cyanide blood concentration of 43 mg/L was detected by toxicological investigation. Discolouration of hypostasis and organs has widely been studied in forensic literature. In our case, we interpreted the unusual pink coloration as the result of the presence of hydroxocobalamin. This substance is a known antidote against cyanide poisoning, indicated because of its efficiency and poor adverse effects. However, its main drawback is to interfere with measurements of many routine biochemical parameters. We have tested the potential influence of this molecule in some routine postmortem investigations. The results are discussed.

  17. Rapidly regulating platelet activity in vivo with an antidote controlled platelet inhibitor.

    PubMed

    Nimjee, Shahid M; Lohrmann, Jens D; Wang, Haichen; Snyder, David J; Cummings, Thomas J; Becker, Richard C; Oney, Sabah; Sullenger, Bruce A

    2012-02-01

    Millions of individuals are prescribed platelet inhibitors, such as aspirin and clopidogrel, to reduce their risk of thrombosis-related clinical events. Unfortunately many platelet inhibitors are contraindicated in surgical settings because of their inherent bleeding risk complicating the treatment of patients who require surgery. We describe the development of a potent antiplatelet agent, an RNA aptamer-termed Ch-9.14-T10 that binds von Willebrand factor (VWF) with high affinity and inhibits thrombosis in a murine carotid artery damage model. As expected, when this potent antiplatelet agent is administered, it greatly increases bleeding from animals that are surgically challenged. To improve this antiplatelet agent's safety profile, we describe the generation of antidotes that can rapidly reverse the activity of Ch-9.14-T10 and limit blood loss from surgically challenged animals. Our work represents the first antidote controllable antiplatelet agent, which could conceivably lead to improved medical management of patients requiring antiplatelet medication who also need surgery.

  18. Nitrocobinamide, a new cyanide antidote that can be administered by intramuscular injection.

    PubMed

    Chan, Adriano; Jiang, Jingjing; Fridman, Alla; Guo, Ling T; Shelton, G Diane; Liu, Ming-Tao; Green, Carol; Haushalter, Kristofer J; Patel, Hemal H; Lee, Jangwoen; Yoon, David; Burney, Tanya; Mukai, David; Mahon, Sari B; Brenner, Matthew; Pilz, Renate B; Boss, Gerry R

    2015-02-26

    Currently available cyanide antidotes must be given by intravenous injection over 5-10 min, making them ill-suited for treating many people in the field, as could occur in a major fire, an industrial accident, or a terrorist attack. These scenarios call for a drug that can be given quickly, e.g., by intramuscular injection. We have shown that aquohydroxocobinamide is a potent cyanide antidote in animal models of cyanide poisoning, but it is unstable in solution and poorly absorbed after intramuscular injection. Here we show that adding sodium nitrite to cobinamide yields a stable derivative (referred to as nitrocobinamide) that rescues cyanide-poisoned mice and rabbits when given by intramuscular injection. We also show that the efficacy of nitrocobinamide is markedly enhanced by coadministering sodium thiosulfate (reducing the total injected volume), and we calculate that ∼1.4 mL each of nitrocobinamide and sodium thiosulfate should rescue a human from a lethal cyanide exposure.

  19. Aluminum phosphide poisoning: Possible role of supportive measures in the absence of specific antidote

    PubMed Central

    Agrawal, Vijay Kumar; Bansal, Abhishek; Singh, Ranjeet Kumar; Kumawat, Bhanwar Lal; Mahajan, Parul

    2015-01-01

    Aluminum phosphide (ALP) poisoning is one of the major causes of suicidal deaths. Toxicity by ALP is caused by the liberation of phosphine gas, which rapidly causes cell hypoxia due to inhibition of oxidative phosphorylation, leading to circulatory failure. Treatment of ALP toxicity is mainly supportive as there is no specific antidote. We recently managed 7 cases of ALP poisoning with severe hemodynamic effects. Patients were treated with supportive measures including gastric lavage with diluted potassium permanganate, coconut oil and sodium-bicarbonate first person account should be avoided in a scientific paper. Intravenous magnesium sulfate, proper hemodynamic monitoring and vasopressors. Four out of 7 survived thus suggesting a role of such supportive measures in the absence of specific antidote for ALP poisoning. PMID:25722553

  20. Aluminum phosphide poisoning: Possible role of supportive measures in the absence of specific antidote.

    PubMed

    Agrawal, Vijay Kumar; Bansal, Abhishek; Singh, Ranjeet Kumar; Kumawat, Bhanwar Lal; Mahajan, Parul

    2015-02-01

    Aluminum phosphide (ALP) poisoning is one of the major causes of suicidal deaths. Toxicity by ALP is caused by the liberation of phosphine gas, which rapidly causes cell hypoxia due to inhibition of oxidative phosphorylation, leading to circulatory failure. Treatment of ALP toxicity is mainly supportive as there is no specific antidote. We recently managed 7 cases of ALP poisoning with severe hemodynamic effects. Patients were treated with supportive measures including gastric lavage with diluted potassium permanganate, coconut oil and sodium-bicarbonate first person account should be avoided in a scientific paper. Intravenous magnesium sulfate, proper hemodynamic monitoring and vasopressors. Four out of 7 survived thus suggesting a role of such supportive measures in the absence of specific antidote for ALP poisoning.

  1. Nitrocobinamide, a New Cyanide Antidote That Can Be Administered by Intramuscular Injection

    PubMed Central

    Chan, Adriano; Jiang, Jingjing; Fridman, Alla; Guo, Ling T.; Shelton, G. Diane; Liu, Ming-Tao; Green, Carol; Haushalter, Kristofer J.; Patel, Hemal H.; Lee, Jangwoen; Yoon, David; Burney, Tanya; Mukai, David; Mahon, Sari B.; Brenner, Matthew; Pilz, Renate B.; Boss, Gerry R.

    2015-01-01

    Currently available cyanide antidotes must be given by intravenous injection over 5–10 min, making them illsuited for treating many people in the field, as could occur in a major fire, an industrial accident, or a terrorist attack. These scenarios call for a drug that can be given quickly, e.g., by intramuscular injection. We have shown that aquohydroxocobinamide is a potent cyanide antidote in animal models of cyanide poisoning, but it is unstable in solution and poorly absorbed after intramuscular injection. Here we show that adding sodium nitrite to cobinamide yields a stable derivative (referred to as nitrocobinamide) that rescues cyanide-poisoned mice and rabbits when given by intramuscular injection. We also show that the efficacy of nitrocobinamide is markedly enhanced by coadministering sodium thiosulfate (reducing the total injected volume), and we calculate that ∼1.4 mL each of nitrocobinamide and sodium thiosulfate should rescue a human from a lethal cyanide exposure. PMID:25650735

  2. Edge structures and properties of triangular antidots in single-layer MoS{sub 2}

    SciTech Connect

    Gan, Li-Yong E-mail: iamyccheng@njtech.edu.cn; Cheng, Yingchun E-mail: iamyccheng@njtech.edu.cn Huang, Wei; Schwingenschlögl, Udo E-mail: iamyccheng@njtech.edu.cn; Yao, Yingbang; Zhao, Yong; Zhang, Xi-xiang

    2016-08-29

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS{sub 2}. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS{sub 2} samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS{sub 2} devices.

  3. Two-dimensional B-C-O alloys: a promising class of 2D materials for electronic devices.

    PubMed

    Zhou, Si; Zhao, Jijun

    2016-04-28

    Graphene, a superior 2D material with high carrier mobility, has limited application in electronic devices due to zero band gap. In this regard, boron and nitrogen atoms have been integrated into the graphene lattice to fabricate 2D semiconducting heterostructures. It is an intriguing question whether oxygen can, as a replacement of nitrogen, enter the sp2 honeycomb lattice and form stable B-C-O monolayer structures. Here we explore the atomic structures, energetic and thermodynamic stability, and electronic properties of various 2D B-C-O alloys using first-principles calculations. Our results show that oxygen can be stably incorporated into the graphene lattice by bonding with boron. The B and O species favor forming alternate patterns into the chain- or ring-like structures embedded in the pristine graphene regions. These B-C-O hybrid sheets can be either metals or semiconductors depending on the B : O ratio. The semiconducting (B2O)nCm and (B6O3)nCm phases exist under the B- and O-rich conditions, and possess a tunable band gap of 1.0-3.8 eV and high carrier mobility, retaining ∼1000 cm2 V(-1) s(-1) even for half coverage of B and O atoms. These B-C-O alloys form a new class of 2D materials that are promising candidates for high-speed electronic devices.

  4. Acceleration of Advanced CN Antidote Agents for Mass Exposure Treatments: DMTS

    DTIC Science & Technology

    2013-10-01

    Agents for Mass Exposure Treatments: DMTS PRINCIPAL INVESTIGATOR: Matthew Brenner, M.D. CONTRACTING ORGANIZATION: University of...Exposure Treatments: DMTS 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-2-0098 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Matthew Brenner...using DMTS alone as the CN antidote, one of the 3 novel therapeutic agents under development with our collaborators. DMTS was dissolved in 15

  5. Acute liver acetaminophen toxicity in rabbits and the use of antidotes: a metabonomic approach in serum.

    PubMed

    Zira, Athina; Mikros, Emmanuel; Giannioti, Konstantina; Galanopoulou, Panagiota; Papalois, Apostolos; Liapi, Charis; Theocharis, Stamatios

    2009-07-01

    The metabonomic approach has been widely used in toxicology to investigate mechanisms of toxicity. In the present study alterations in the metabolic profiles, monitored by (1)H-NMR spectroscopy, on serum samples in acetaminophen (APAP)-induced liver injury in rabbits were examined. Furthermore, the effect of the established antidote N-acetylcysteine (NAC) and the proposed antidotes silybinin (SIL), cimetidine (CIM) and SIL/CIM was also investigated. A single dose of APAP (2 g kg(-1) b.w., i.g.) was administered to rabbits and APAP combined with the antidotes SIL, CIM and NAC. Animals were sacrificed at 24 h post-APAP treatment. Healthy untreated animals served as controls. (1)H-NMR spectra of serum samples were acquired and underwent principal component analysis (PCA). Acute liver injury was verified by histopathological examination and the alterations of serum biochemical enzymes AST and ALT. (1)H-NMR spectroscopy revealed variations in the serum metabolic profile of APAP-intoxicated rabbits compared with controls. Co-administration of APAP with NAC, CIM and SIL + CIM seems to ameliorate the metabolic profile of animals compared with simply APAP-treated ones. In this study, the model of APAPinduced liver injury was successfully described using the (1)H-NMR based metabonomic approach in serum. Furthermore, the use of antidotes that reduced the toxic insult was also recorded using this technique. The combination of NMR spectroscopy and PCA is a rapid methodology, capable of detecting alterations in the metabolic profile, and produces adequate models that could be used for the characterization of unknown samples, both experimental and clinical, reinforcing its future use in clinical settings.

  6. Disulfides as Cyanide Antidotes: Evidence for a New In Vivo Oxidative Pathway for Cyanide Detoxification

    DTIC Science & Technology

    2009-01-01

    defense against cyanide intoxication . The oxidation of disulfides to the corresponding thiosulfinate or thiosulfonate will result in facilitating their...high probability (1). While antidotes for cyanide intoxication exist (2-4), it has yet to be shown that they can be effectively administered in the...garlic] have been found to be effective as in vivo therapeutic agents for cyanide intoxication (10, 11). It is believed that the efficacy of these

  7. Effectiveness of intramuscularly administered cyanide antidotes on methemoglobin formation and survival.

    PubMed

    Vick, J A; Von Bredow, J D

    1996-01-01

    Successful first aid therapy for cyanide intoxication is dependent upon immediate administration of antidotes which directly or indirectly interact with the cyanide ion to remove it from circulation. Owing to the severe respiratory, cardiovascular and convulsive episodes following acute cyanide intoxication, the most practical approach is to administer antidotes by intramuscular injection. Exceptionally rapid methemoglobin formers-hydroxylamine hydrochloride (HH) and dimethylaminophenol (DMAP)-are usually able to prevent the lethal effect of cyanide following intramuscular injections in doses sufficient to induce 20% methemoglobin (HH = 20 mg kg-1 and DMAP = 2 mg kg-1). Sodium nitrite, the methemoglobin inducer approved for military use, must be administered by intravenous infusion because it is not an effective cyanide antidote by the intramuscular route. In the normal unintoxicated animal an intramuscular injection of 20 mg kg-1 sodium nitrite will form 20% methemoglobin; however, in acute cyanide intoxication the associated severe bradycardia appears to limit the rate of absorption and thus the rapid formation of methemoglobin. If the bradycardia is prevented or reversed by atropine, the rate of absorption of sodium nitrite and the formation of methemoglobin is able to reverse the otherwise lethal effects of cyanide. Thus, an intramuscularly administered combination of 20 mg kg-1 sodium nitrite and 1 mg kg-1 atropine sulfate, rapidly absorbed from the intramuscular site, appears to achieve the same degree of effectiveness against acute cyanide intoxication as intramuscularly administered HH or DMAP. It would appear from these studies that HH, DMAP and sodium nitrite with atropine are all potentially effective intramuscular antidotes for acute cyanide poisoning.

  8. Antidotes, antibody-mediated immunity and the future of pharmaceutical product development.

    PubMed

    Caoili, Salvador Eugenio C

    2013-02-01

    If new scientific knowledge is to be more efficiently generated and applied toward the advancement of health, human safety must be more effectively addressed in the conduct of research. Given the present difficulties of accurately predicting biological outcomes of novel interventions in vivo, the imperative of human safety suggests the development of novel pharmaceutical products in tandem with their prospective antidotes in anticipation of possible adverse events, to render the risks of initial clinical trials more acceptable from a regulatory standpoint. Antibody-mediated immunity provides a generally applicable mechanistic basis for developing antidotes to both biologicals and small-molecule drugs (such that antibodies may serve as antidotes to pharmaceutical agents as a class including other antibodies) and also for the control and prevention of both infectious and noninfectious diseases via passive or active immunization. Accordingly, the development of prophylactic or therapeutic passive-immunization strategies using antipeptide antibodies is a plausible prelude to the development of corresponding active-immunization strategies using peptide-based vaccines. In line with this scheme, global proliferation of antibody- and vaccine-production technologies, especially those that obviate dependence on the cold chain for storage and transport of finished products, could provide geographically distributed breakout capability against emerging and future health challenges.

  9. Nonclinical Evaluation of Novel Cationically Modified Polysaccharide Antidotes for Unfractionated Heparin

    PubMed Central

    Kalaska, Bartlomiej; Kaminski, Kamil; Sokolowska, Emilia; Czaplicki, Dominik; Kujdowicz, Monika; Stalinska, Krystyna; Bereta, Joanna; Szczubialka, Krzysztof; Pawlak, Dariusz; Nowakowska, Maria; Mogielnicki, Andrzej

    2015-01-01

    Protamine, the only registered antidote of unfractionated heparin (UFH), may produce a number of adverse effects, such as anaphylactic shock or serious hypotension. We aimed to develop an alternative UFH antidote as efficient as protamine, but safer and easier to produce. As a starting material, we have chosen generally non-toxic, biocompatible, widely available, inexpensive, and easy to functionalize polysaccharides. Our approach was to synthesize, purify and characterize cationic derivatives of dextran, hydroxypropylcellulose, pullulan and γ-cyclodextrin, then to screen them for potential heparin-reversal activity using an in vitro assay and finally examine efficacy and safety of the most active polymers in Wistar rat and BALB/c mouse models of experimentally induced arterial and venous thrombosis. Efficacy studies included the measurement of thrombus formation, activated partial thromboplastin time, bleeding time, and anti-factor Xa activity; safety studies included the measurement of hemodynamic, hematologic and immunologic parameters. Linear, high molecular weight dextran substituted with glycidyltrimethylammonium chloride groups at a ratio of 0.65 per glucose unit (Dex40-GTMAC3) is the most potent and the safest UFH inhibitor showing activity comparable to that of protamine while possessing lower immunogenicity. Cationic polysaccharides of various structures neutralize UFH. Dex40-GTMAC3 is a promising and potentially better UFH antidote than protamine. PMID:25781030

  10. Nonclinical evaluation of novel cationically modified polysaccharide antidotes for unfractionated heparin.

    PubMed

    Kalaska, Bartlomiej; Kaminski, Kamil; Sokolowska, Emilia; Czaplicki, Dominik; Kujdowicz, Monika; Stalinska, Krystyna; Bereta, Joanna; Szczubialka, Krzysztof; Pawlak, Dariusz; Nowakowska, Maria; Mogielnicki, Andrzej

    2015-01-01

    Protamine, the only registered antidote of unfractionated heparin (UFH), may produce a number of adverse effects, such as anaphylactic shock or serious hypotension. We aimed to develop an alternative UFH antidote as efficient as protamine, but safer and easier to produce. As a starting material, we have chosen generally non-toxic, biocompatible, widely available, inexpensive, and easy to functionalize polysaccharides. Our approach was to synthesize, purify and characterize cationic derivatives of dextran, hydroxypropylcellulose, pullulan and γ-cyclodextrin, then to screen them for potential heparin-reversal activity using an in vitro assay and finally examine efficacy and safety of the most active polymers in Wistar rat and BALB/c mouse models of experimentally induced arterial and venous thrombosis. Efficacy studies included the measurement of thrombus formation, activated partial thromboplastin time, bleeding time, and anti-factor Xa activity; safety studies included the measurement of hemodynamic, hematologic and immunologic parameters. Linear, high molecular weight dextran substituted with glycidyltrimethylammonium chloride groups at a ratio of 0.65 per glucose unit (Dex40-GTMAC3) is the most potent and the safest UFH inhibitor showing activity comparable to that of protamine while possessing lower immunogenicity. Cationic polysaccharides of various structures neutralize UFH. Dex40-GTMAC3 is a promising and potentially better UFH antidote than protamine.

  11. Identification, solubility enhancement and in vivo testing of a cyanide antidote candidate.

    PubMed

    Kovacs, Kristof; Ancha, Madhuri; Jane, Mario; Lee, Stephen; Angalakurthi, Siva; Negrito, Maelani; Rasheed, Senan; Nwaneri, Assumpta; Petrikovics, Ilona

    2013-06-14

    Present studies focused on the in vitro testing, the solubility enhancement and the in vivo testing of methyl propyl trisulfide (MPTS), a newly identified sulfur donor to treat cyanide (CN) intoxication. To enhance the solubility of the lipophilic MPTS, various FDA approved co-solvents, surfactants and their combinations were applied. The order of MPTS solubility in the given co-solvents was found to be the following: ethanol > PEG 200 ≈ PEG400 ≈ PEG300 > PG. The maximum solubility of MPTS was found at 90% ethanol of 177.11 ± 12.17 mg/ml. The order of MPTS solubility in different surfactants is Cremophor EL>Cremophor RH40>polysorbate 80>sodium deoxycholate>sodium cholate. The maximum solubility of 40.99 mg/ml was achieved with 20% Cremophor EL. A synergistic solubilizing effect encountered with the combination of 20% Cremophor EL+75% ethanol lead to a 2900-fold increase (compared to water solubility) in solubility. The in vivo efficacy using intramuscular administration was determined on a therapeutic mice model and expressed as a ratio of CN LD50 with and without the test antidote(s) (APR). Intramuscular administration was shown to be effective and the therapeutic antidotal protection by MPTS alone and MPTS+thiosulfate (TS) was significantly higher than the present therapy of TS.

  12. Enhancement of exchange bias and ferromagnetic resonance frequency by using multilayer antidot arrays

    NASA Astrophysics Data System (ADS)

    Phuoc, Nguyen N.; Lim, S. L.; Xu, F.; Ma, Y. G.; Ong, C. K.

    2008-11-01

    A systematic investigation of the dependences of the exchange bias and the ferromagnetic resonance frequency on the pore size of the antidot arrays fabricated by depositing Permalloy-FeMn multilayer thin films onto self-organized porous anodic aluminum oxide membranes was carried out. The magnetic and microwave properties of the antidot arrays with different pore sizes ranging from 30 to 80 nm are characterized and compared with that of the continuous thin films. It was found that the exchange bias field and the ferromagnetic resonance frequency are increased with the increase of the pore size, which may tentatively be interpreted in the framework of the random field model. It was also found that by using the antidot arrays in the best condition (the FeNi thickness is 20 nm and the pore size is 80 nm), one can enhance the exchange bias field from 65 to 135 Oe and the ferromagnetic resonance frequency from 3.1 to 4.1 GHz accordingly.

  13. Contributions of ionic interactions and protein dynamics to cytochrome P450 2D6 (CYP2D6) substrate and inhibitor binding.

    PubMed

    Wang, An; Stout, C David; Zhang, Qinghai; Johnson, Eric F

    2015-02-20

    P450 2D6 contributes significantly to the metabolism of >15% of the 200 most marketed drugs. Open and closed crystal structures of P450 2D6 thioridazine complexes were obtained using different crystallization conditions. The protonated piperidine moiety of thioridazine forms a charge-stabilized hydrogen bond with Asp-301 in the active sites of both complexes. The more open conformation exhibits a second molecule of thioridazine bound in an expanded substrate access channel antechamber with its piperidine moiety forming a charge-stabilized hydrogen bond with Glu-222. Incubation of the crystalline open thioridazine complex with alternative ligands, prinomastat, quinidine, quinine, or ajmalicine, displaced both thioridazines. Quinine and ajmalicine formed charge-stabilized hydrogen bonds with Glu-216, whereas the protonated nitrogen of quinidine is equidistant from Asp-301 and Glu-216 with protonated nitrogen H-bonded to a water molecule in the access channel. Prinomastat is not ionized. Adaptations of active site side-chain rotamers and polypeptide conformations were evident between the complexes, with the binding of ajmalicine eliciting a closure of the open structure reflecting in part the inward movement of Glu-216 to form a hydrogen bond with ajmalicine as well as sparse lattice restraints that would hinder adaptations. These results indicate that P450 2D6 exhibits sufficient elasticity within the crystal lattice to allow the passage of compounds between the active site and bulk solvent and to adopt a more closed form that adapts for binding alternative ligands with different degrees of closure. These crystals provide a means to characterize substrate and inhibitor binding to the enzyme after replacement of thioridazine with alternative compounds.

  14. Fractal properties of the lattice Lotka-Volterra model.

    PubMed

    Tsekouras, G A; Provata, A

    2002-01-01

    The lattice Lotka-Volterra (LLV) model is studied using mean-field analysis and Monte Carlo simulations. While the mean-field phase portrait consists of a center surrounded by an infinity of closed trajectories, when the process is restricted to a two-dimensional (2D) square lattice, local inhomogeneities/fluctuations appear. Spontaneous local clustering is observed on lattice and homogeneous initial distributions turn into clustered structures. Reactions take place only at the interfaces between different species and the borders adopt locally fractal structure. Intercluster surface reactions are responsible for the formation of local fluctuations of the species concentrations. The box-counting fractal dimension of the LLV dynamics on a 2D support is found to depend on the reaction constants while the upper bound of fractality determines the size of the local oscillators. Lacunarity analysis is used to determine the degree of clustering of homologous species. Besides the spontaneous clustering that takes place on a regular 2D lattice, the effects of fractal supports on the dynamics of the LLV are studied. For supports of dimensionality D(s)<2 the lattice can, for certain domains of the reaction constants, adopt a poisoned state where only one of the species survives. By appropriately selecting the fractal dimension of the substrate, it is possible to direct the system into a poisoned or oscillatory steady state at will.

  15. sd(2) Graphene: Kagome band in a hexagonal lattice.

    PubMed

    Zhou, Miao; Liu, Zheng; Ming, Wenmei; Wang, Zhengfei; Liu, Feng

    2014-12-05

    Graphene, made of sp^{2} hybridized carbon, is characterized with a Dirac band, representative of its underlying 2D hexagonal lattice. The fundamental understanding of graphene has recently spurred a surge in the search for 2D topological quantum phases in solid-state materials. Here, we propose a new form of 2D material, consisting of sd^{2} hybridized transition metal atoms in hexagonal lattice, called sd^{2} "graphene." The sd^{2} graphene is characterized by bond-centered electronic hopping, which transforms the apparent atomic hexagonal lattice into the physics of a kagome lattice that may exhibit a wide range of topological quantum phases. Based on first-principles calculations, room-temperature quantum anomalous Hall states with an energy gap of ∼0.1  eV are demonstrated for one such lattice made of W, which can be epitaxially grown on a semiconductor surface of 1/3 monolayer Cl-covered Si(111), with high thermodynamic and kinetic stability.

  16. Comparative metabolic capabilities and inhibitory profiles of CYP2D6.1, CYP2D6.10, and CYP2D6.17.

    PubMed

    Shen, Hongwu; He, Minxia M; Liu, Houfu; Wrighton, Steven A; Wang, Li; Guo, Bin; Li, Chuan

    2007-08-01

    Polymorphisms in the cytochrome P450 2D6 (CYP2D6) gene are a major cause of pharmacokinetic variability in human. Although the poor metabolizer phenotype is known to be caused by two null alleles leading to absence of functional CYP2D6 protein, the large variability among individuals with functional alleles remains mostly unexplained. Thus, the goal of this study was to examine the intrinsic enzymatic differences that exist among the several active CYP2D6 allelic variants. The relative catalytic activities (enzyme kinetics) of three functionally active human CYP2D6 allelic variants, CYP2D6.1, CYP2D6.10, and CYP2D6.17, were systematically investigated for their ability to metabolize a structurally diverse set of clinically important CYP2D6-metabolized drugs [atomoxetine, bufuralol, codeine, debrisoquine, dextromethorphan, (S)-fluoxetine, nortriptyline, and tramadol] and the effects of various CYP2D6-inhibitors [cocaine, (S)-fluoxetine, (S)-norfluoxetine, imipramine, quinidine, and thioridazine] on these three variants. The most significant difference observed was a consistent but substrate-dependent decease in the catalytic efficiencies of cDNA-expressed CYP2D6.10 and CYP2D6.17 compared with CYP2D6.1, yielding 1.32 to 27.9 and 7.33 to 80.4% of the efficiency of CYP2D6.1, respectively. The most important finding from this study is that there are mixed effects on the functionally reduced allelic variants in enzyme-substrate affinity or enzyme-inhibitor affinity, which is lower, higher, or comparable to that for CYP2D6.1. Considering the rather high frequencies of CYP2D6*10 and CYP2D6*17 alleles for Asians and African Americans, respectively, these data provide further insight into ethnic differences in CYP2D6-mediated drug metabolism. However, as with all in vitro to in vivo extrapolations, caution should be applied to the clinical consequences.

  17. Holographic method for site-resolved detection of a 2D array of ultracold atoms

    NASA Astrophysics Data System (ADS)

    Hoffmann, Daniel Kai; Deissler, Benjamin; Limmer, Wolfgang; Hecker Denschlag, Johannes

    2016-08-01

    We propose a novel approach to site-resolved detection of a 2D gas of ultracold atoms in an optical lattice. A near-resonant laser beam is coherently scattered by the atomic array, and after passing a lens its interference pattern is holographically recorded by superimposing it with a reference laser beam on a CCD chip. Fourier transformation of the recorded intensity pattern reconstructs the atomic distribution in the lattice with single-site resolution. The holographic detection method requires only about two hundred scattered photons per atom in order to achieve a high reconstruction fidelity of 99.9 %. Therefore, additional cooling during detection might not be necessary even for light atomic elements such as lithium. Furthermore, first investigations suggest that small aberrations of the lens can be post-corrected in imaging processing.

  18. Spin-spin interaction effect in 2D Extended Hubbard Model

    NASA Astrophysics Data System (ADS)

    Zouhair, A.; Harir, S.; Bennai, M.; Boughaleb, Y.

    2014-09-01

    Using an exact diagonlization for finite square lattice and taking into account the periodic boundary conditions in the two directions, we study the spin-spin interaction effect on some local electronic properties for antiferromagnetic correlated electrons system. We have considered an Extended Hubbard Model (EHM) including on-site coulomb interaction energy U and spin-spin interaction term J. The diagonlization of this 2D EHM model allows us to study J effect on some local properties for finite square lattice. The analysis of the obtained results shows that the introduction of spin-spin interaction induces a supplementary conductivity for antiferromagnetic correlated electrons system, even in the strong on-site interaction regime.

  19. Nanostructured 2D cellular materials in silicon by sidewall transfer lithography NEMS

    NASA Astrophysics Data System (ADS)

    Syms, Richard R. A.; Liu, Dixi; Ahmad, Munir M.

    2017-07-01

    Sidewall transfer lithography (STL) is demonstrated as a method for parallel fabrication of 2D nanostructured cellular solids in single-crystal silicon. The linear mechanical properties of four lattices (perfect and defected diamond; singly and doubly periodic honeycomb) with low effective Young’s moduli and effective Poisson’s ratio ranging from positive to negative are modelled using analytic theory and the matrix stiffness method with an emphasis on boundary effects. The lattices are fabricated with a minimum feature size of 100 nm and an aspect ratio of 40:1 using single- and double-level STL and deep reactive ion etching of bonded silicon-on-insulator. Nanoelectromechanical systems (NEMS) containing cellular materials are used to demonstrate stretching, bending and brittle fracture. Predicted edge effects are observed, theoretical values of Poisson’s ratio are verified and failure patterns are described.

  20. 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.