1
|
Nambu Y, Barker J, Okino Y, Kikkawa T, Shiomi Y, Enderle M, Weber T, Winn B, Graves-Brook M, Tranquada JM, Ziman T, Fujita M, Bauer GEW, Saitoh E, Kakurai K. Observation of Magnon Polarization. Phys Rev Lett 2020; 125:027201. [PMID: 32701305 DOI: 10.1103/physrevlett.125.027201] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
We measure the mode-resolved direction of the precessional motion of the magnetic order, i.e., magnon polarization, via the chiral term of inelastic polarized neutron scattering spectra. The magnon polarization is a unique and unambiguous signature of magnets and is important in spintronics, affecting thermodynamic properties such as the magnitude and sign of the spin Seebeck effect. However, it has never been directly measured in any material until this work. The observation of both signs of magnon polarization in Y_{3}Fe_{5}O_{12} also gives direct proof of its ferrimagnetic nature. The experiments agree very well with atomistic simulations of the scattering cross section.
Collapse
Affiliation(s)
- Y Nambu
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - J Barker
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Y Okino
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - T Kikkawa
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- WPI-AIMR, Tohoku University, Sendai 980-8577, Japan
| | - Y Shiomi
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - M Enderle
- Institut Laue-Langevin (ILL), 38042 Grenoble, France
| | - T Weber
- Institut Laue-Langevin (ILL), 38042 Grenoble, France
| | - B Winn
- Oak Ridge National Lab (ORNL), Oak Ridge, Tennessee 37831, USA
| | - M Graves-Brook
- Oak Ridge National Lab (ORNL), Oak Ridge, Tennessee 37831, USA
| | - J M Tranquada
- Brookhaven National Lab (BNL), Upton, New York 11973-5000, USA
| | - T Ziman
- Institut Laue-Langevin (ILL), 38042 Grenoble, France
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - M Fujita
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - G E W Bauer
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- WPI-AIMR, Tohoku University, Sendai 980-8577, Japan
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, Netherlands
| | - E Saitoh
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- WPI-AIMR, Tohoku University, Sendai 980-8577, Japan
- Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
| | - K Kakurai
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Saitama 351-0198, Japan
- Materials Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
| |
Collapse
|
2
|
Hoffknecht P, Enderle M, Papita A, Keller R, Steger U, Dickgreber N. Gastrointestinale Perforationen als schwerwiegende Komplikation unter Therapie mit Tyrosinkinaseinhibitoren beim nicht-kleinzelligen Lungenkarzinom. Pneumologie 2017. [DOI: 10.1055/s-0037-1598462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- P Hoffknecht
- Klinik für Pneumologie, Thoraxonkologie und Beatmungsmedizin, Mathias Spital Rheine
| | - M Enderle
- Klinik für Pneumologie, Thoraxonkologie und Beatmungsmedizin, Mathias Spital Rheine
| | - A Papita
- Klinik für Pneumologie, Thoraxonkologie und Beatmungsmedizin, Mathias Spital Rheine
| | - R Keller
- Klinik für Innere Medizin, Gastroenterologie, Mathias-Spital Rheine
| | - U Steger
- Klinik für Allgemein- und Viszeralchirurgie, Mathias-Spita Rheine
| | - N Dickgreber
- Klinik für Pneumologie, Thoraxonkologie und Beatmungsmedizin, Mathias Spital Rheine
| |
Collapse
|
3
|
Babkevich P, Freeman PG, Enderle M, Prabhakaran D, Boothroyd AT. Direct evidence for charge stripes in a layered cobalt oxide. Nat Commun 2016; 7:11632. [PMID: 27212023 PMCID: PMC4879241 DOI: 10.1038/ncomms11632] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/14/2016] [Indexed: 11/23/2022] Open
Abstract
Recent experiments indicate that static stripe-like charge order is generic to the hole-doped copper oxide superconductors and competes with superconductivity. Here we show that a similar type of charge order is present in La5/3Sr1/3CoO4, an insulating analogue of the copper oxide superconductors containing cobalt in place of copper. The stripe phase we have detected is accompanied by short-range, quasi-one-dimensional, antiferromagnetic order, and provides a natural explanation for the distinctive hourglass shape of the magnetic spectrum previously observed in neutron-scattering measurements of La2−xSrxCoO4 and many hole-doped copper oxide superconductors. The results establish a solid empirical basis for theories of the hourglass spectrum built on short-range, quasi-static, stripe correlations. The nature of the magnetic ground state giving rise to the hourglass-shaped magnetic spectrum common among high-Tc superconductors is a matter of debate. Here, Babkevich et al. detect the presence of stripe charge order accompanied by quasi-one-dimensional antiferromagnetic order in La5/3Sr1/3CoO4, providing a natural explanation for this characteristic spectrum.
Collapse
Affiliation(s)
- P Babkevich
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - P G Freeman
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, Lancashire PR1 2HE, UK
| | - M Enderle
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - D Prabhakaran
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, UK
| | - A T Boothroyd
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, UK
| |
Collapse
|
4
|
Enderle M, Hoffknecht P, May G, Fischer S, Dickgreber N. Mediastinale Reevaluation nach onkologischer Vortherapie bei Bronchialkarzinom mittels EBUS-TBNA. Pneumologie 2016. [DOI: 10.1055/s-0036-1572290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
5
|
Wagenpfeil J, Schollig C, Mayer V, Nold B, Ederer M, Neugebauer A, Rothmund R, Kramer B, Schwentner C, Schenk M, Wallwiener D, Stenzl A, Enderle M, Sawodny O, Feuer R. Finite-element-modeling of egg white as a substitute for tissue coagulation during bipolar radiofrequency-induced thermofusion. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2015:5791-6. [PMID: 26737608 DOI: 10.1109/embc.2015.7319708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Radiofrequency-induced thermofusion is a frequently used electrosurgical procedure for the sealing of blood vessels. A disadvantage of vessel sealing instruments is that the generated thermal energy spreads to the surrounding tissue and may irreversibly damage it. This is particularly problematic when operating close to sensitive structures such as nerves. Given their advantages, there is nonetheless a lot of interest in using bipolar vessel sealing for surgical procedures. To select instruments that may be safely used in such cases, it is important to reliably quantify the thermal spread to the surrounding tissue. Mathematical models can help to evaluate the transient behavior, that is the evolution of the thermal spread over time, more precisely. A finite element model allows for a detailed analysis of inhomogeneities in the spatial temperature distribution. As a first step towards a finite model of the bipolar vessel sealing process, a model of the coagulation of chicken egg white is presented here. Egg white has thermal and electrical properties that are very similar to tissue, making it suitable as a substitute for the analysis of the coagulation process. It has the additional advantage, that the spatial and temporal evolution of the thermal spread can be visually gauged. The presented model describes the experimentally observed spatial temperature distribution, the shape of the coagulated egg white, and the formation of hotspots. Furthermore, it is shown that the model can correctly predict the shape of the coagulated egg white in further experiments.
Collapse
|
6
|
Hoffknecht P, Enderle M, Lavae-Mokhtari M, May G, Freermann S, Fischer S, Dickgreber N. Akute interstitielle Pneumonitis nach taxanhaltiger Chemotherapie eines B2-Thymoms – eine seltene, nicht immer therapieinduzierte Komplikation. Pneumologie 2015. [DOI: 10.1055/s-0035-1544665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
7
|
Wagenpfeil J, Nold B, Fischer K, Neugebauer A, Rothmund R, Krämer B, Brucker S, Mischinger J, Schwentner C, Schenk M, Wallwiener D, Stenzl A, Enderle M, Sawodny O, Ederer M. A mathematical model of bipolar radiofrequency-induced thermofusion. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2014:5683-6. [PMID: 25571285 DOI: 10.1109/embc.2014.6944917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Bipolar radiofrequency-induced thermofusion has become a widely accepted method successfully used in open and particularly in minimally-invasive surgery for the sealing of blood vessels and tissue of up to several millimeters diameter. Despite its wide-spread application, the thermofusion process itself is not well understood on a quantitative and dynamic level, and manufacturers largely rely on trial-and-error methods to improve existing instruments. To predict the effect of alternative generator control strategies and to allow for a more systematic approach to improve thermofusion instruments, a mathematical model of the thermofusion process is developed. The system equations describe the spatial and temporal evolution of the tissue temperature due to Joule heating and heat transfer, and the loss of tissue water due to vaporization. The resulting effects on the tissue properties, most importantly the electrical resistivity, heat capacity and thermal conductivity, are considered as well. Experimental results indicate that the extent of the lateral thermal damage is directly affected by Joule heating of the lateral tissue. The experimental findings are supported by simulation results using the proposed mathematical model of thermofusion.
Collapse
|
8
|
Piazza BD, Mourigal M, Christensen NB, Nilsen GJ, Tregenna-Piggott P, Perring TG, Enderle M, McMorrow DF, Ivanov DA, Rønnow HM. Fractional excitations in the square lattice quantum antiferromagnet. Nat Phys 2015; 11:62-68. [PMID: 25729400 PMCID: PMC4340518 DOI: 10.1038/nphys3172] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 10/29/2014] [Indexed: 05/30/2023]
Abstract
Quantum magnets have occupied the fertile ground between many-body theory and low-temperature experiments on real materials since the early days of quantum mechanics. However, our understanding of even deceptively simple systems of interacting spins-1/2 is far from complete. The quantum square-lattice Heisenberg antiferromagnet (QSLHAF), for example, exhibits a striking anomaly of hitherto unknown origin in its magnetic excitation spectrum. This quantum effect manifests itself for excitations propagating with the specific wave vector (π, 0). We use polarized neutron spectroscopy to fully characterize the magnetic fluctuations in the metal-organic compound CFTD, a known realization of the QSLHAF model. Our experiments reveal an isotropic excitation continuum at the anomaly, which we analyse theoretically using Gutzwiller-projected trial wavefunctions. The excitation continuum is accounted for by the existence of spatially-extended pairs of fractional S=1/2 quasiparticles, 2D analogues of 1D spinons. Away from the anomalous wave vector, these fractional excitations are bound and form conventional magnons. Our results establish the existence of fractional quasiparticles in the high-energy spectrum of a quasi-two-dimensional antiferromagnet, even in the absence of frustration.
Collapse
Affiliation(s)
- B Dalla Piazza
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland
| | - M Mourigal
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland ; Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9, France ; Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - N B Christensen
- Department of Physics, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby, Denmark ; Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - G J Nilsen
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland ; Department of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ, United Kingdom
| | - P Tregenna-Piggott
- Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - T G Perring
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, United Kingdom
| | - M Enderle
- Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9, France
| | - D F McMorrow
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH, United Kingdom
| | - D A Ivanov
- Institute for Theoretical Physics, ETH Zürich, CH-8093 Zürich, Switzerland ; Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
| | - H M Rønnow
- Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Switzerland ; RIKEN Centre for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| |
Collapse
|
9
|
Hoffknecht P, Innig G, Hasselblatt M, Länger F, Enderle M, Haberland K, Dickgreber N. Effektive Therapie mit Afatinib bei leptomeningealer Metastasierung eines EGFR-mutierten Adenokarzinoms mit sekundärer T790M-Mutation. Pneumologie 2014. [DOI: 10.1055/s-0034-1367981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
10
|
Voneshen DJ, Refson K, Borissenko E, Krisch M, Bosak A, Piovano A, Cemal E, Enderle M, Gutmann MJ, Hoesch M, Roger M, Gannon L, Boothroyd AT, Uthayakumar S, Porter DG, Goff JP. Suppression of thermal conductivity by rattling modes in thermoelectric sodium cobaltate. Nat Mater 2013; 12:1028-1032. [PMID: 23975057 DOI: 10.1038/nmat3739] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 07/24/2013] [Indexed: 06/02/2023]
Abstract
The need for both high electrical conductivity and low thermal conductivity creates a design conflict for thermoelectric systems, leading to the consideration of materials with complicated crystal structures. Rattling of ions in cages results in low thermal conductivity, but understanding the mechanism through studies of the phonon dispersion using momentum-resolved spectroscopy is made difficult by the complexity of the unit cells. We have performed inelastic X-ray and neutron scattering experiments that are in remarkable agreement with our first-principles density-functional calculations of the phonon dispersion for thermoelectric Na(0.8)CoO2, which has a large-period superstructure. We have directly observed an Einstein-like rattling mode at low energy, involving large anharmonic displacements of the sodium ions inside multi-vacancy clusters. These rattling modes suppress the thermal conductivity by a factor of six compared with vacancy-free NaCoO2. Our results will guide the design of the next generation of materials for applications in solid-state refrigerators and power recovery.
Collapse
Affiliation(s)
- D J Voneshen
- Department of Physics, Royal Holloway, University of London, Egham TW20 0EX, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Franke KJ, Nilius G, Rühle KH, Enderle M, Weyhern CHV. Die Kryo-Nadel - ein neues Instrument zur EBUS-gesteuerten histologischen Biopsatentnahme. Pneumologie 2013. [DOI: 10.1055/s-0033-1334495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
12
|
Hofmann T, Kumar P, Enderle M, Wallacher D. Growth of highly oriented deuterium crystals in silicon nanochannels. Phys Rev Lett 2013; 110:065505. [PMID: 23432273 DOI: 10.1103/physrevlett.110.065505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 12/10/2012] [Indexed: 06/01/2023]
Abstract
The structure of solid deuterium confined in 9 nm wide tubular silicon nanochannels has been studied by means of elastic neutron scattering techniques. As a result we report the formation of fcc D(2) as the stable solid phase in confinement in contrast to the hcp bulk structure. Further, a preferred alignment of D(2) nanocrystals with respect to the surrounding crystalline silicon matrix is discussed in terms of heteroepitaxial growth of solid D(2) on crystalline pore walls.
Collapse
Affiliation(s)
- T Hofmann
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
| | | | | | | |
Collapse
|
13
|
Abstract
The spin waves in a powdered sample of a quasi-two-dimensional antiferromagnet, FePS(3), have been measured using neutron inelastic scattering. The data could be modelled and the exchange interactions determined using a two-dimensional Heisenberg Hamiltonian with single ion anisotropy. A suitable fit to the data could only be achieved by including magnetic interactions up to the third nearest neighbour, which is consistent with the findings for other members of the MPS(3) family (M=transition metal). The best fit parameters at 6 K were J(1) = 1.49 meV, J(2) = 0.04 meV, J(3) =- 0.6 meV, with an anisotropy of Δ = 3.7 meV. Measurements as a function of temperature give a coarse measure of the behaviour of the anisotropy and the nature of the phase transition.
Collapse
Affiliation(s)
- A R Wildes
- Institut Laue-Langevin, Grenoble, France.
| | | | | | | | | |
Collapse
|
14
|
Mourigal M, Enderle M, Fåk B, Kremer RK, Law JM, Schneidewind A, Hiess A, Prokofiev A. Evidence of a bond-nematic phase in LiCuVO4. Phys Rev Lett 2012; 109:027203. [PMID: 23030203 DOI: 10.1103/physrevlett.109.027203] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Indexed: 06/01/2023]
Abstract
Polarized and unpolarized neutron scattering experiments on the frustrated ferromagnetic spin-1/2 chain LiCuVO4 show that the phase transition at H(Q) of 8 T is driven by quadrupolar fluctuations and that dipolar correlations are short range with moments parallel to the applied magnetic field in the high-field phase. Heat-capacity measurements evidence a phase transition into this high-field phase, with an anomaly clearly different from that at low magnetic fields. Our experimental data are consistent with a picture where the ground state above H(Q) has a next-nearest neighbor bond-nematic order along the chains with a fluidlike coherence between weakly coupled chains.
Collapse
Affiliation(s)
- M Mourigal
- Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9, France
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Enderle M, Cremer D, Scholz C, Seiffert-Petersheim U, Fehr R. Lokaler Fachplan Gesundheit – Ergebnisse der Pilotphase 2010 mit nordrhein-westfälischen Gesundheitsämtern. Gesundheitswesen 2011. [DOI: 10.1055/s-0031-1283442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
16
|
Loire M, Simonet V, Petit S, Marty K, Bordet P, Lejay P, Ollivier J, Enderle M, Steffens P, Ressouche E, Zorko A, Ballou R. Parity-broken chiral spin dynamics in Ba₃NbFe₃Si₂O₁₄. Phys Rev Lett 2011; 106:207201. [PMID: 21668258 DOI: 10.1103/physrevlett.106.207201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 12/22/2010] [Indexed: 05/30/2023]
Abstract
The spin-wave excitations emerging from the chiral helically modulated 120° magnetic order in a langasite Ba₃NbFe₃Si₂O₁₄ enantiopure crystal were investigated by unpolarized and polarized inelastic neutron scattering. A dynamical fingerprint of the chiral ground state is obtained, singularized by (i) spectral weight asymmetries answerable to the structural chirality and (ii) a full chirality of the spin correlations observed over the whole energy spectrum. The intrinsic chiral nature of the spin waves' elementary excitations is shown in the absence of macroscopic time-reversal symmetry breaking.
Collapse
Affiliation(s)
- M Loire
- Institut Néel, CNRS and Université Joseph Fourier, BP166, 38042 Grenoble Cedex 9, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Rempp H, Mezger D, Voigtländer M, Enderle M, Hoffmann R, Pereira PL, Claussen CD, Clasen S. Ex-vivo Vergleichsstudie von mono- und bipolaren intern gas- und wassergekühlten Radiofrequenzapplikatoren. ROFO-FORTSCHR RONTG 2011. [DOI: 10.1055/s-0031-1279419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
18
|
Eickhoff A, Enderle M, Hartmann D, Eickhoff J, Riemann J, Jakobs R. Effectiveness and Safety of PRECISE APC for the Treatment of Bleeding Gastrointestinal Angiodysplasia - a Retrospective Evaluation. Z Gastroenterol 2011; 49:195-200. [DOI: 10.1055/s-0029-1245785] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
19
|
Enderle M, Fåk B, Mikeska HJ, Kremer RK, Prokofiev A, Assmus W. Two-spinon and four-spinon continuum in a frustrated ferromagnetic spin-1/2 chain. Phys Rev Lett 2010; 104:237207. [PMID: 20867269 DOI: 10.1103/physrevlett.104.237207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Indexed: 05/29/2023]
Abstract
Inelastic neutron scattering measurements show the existence of a strong two-spinon continuum in the frustrated ferromagnetic spin-1/2 chain compound LiCuVO4. The dynamic magnetic susceptibility is well described by a mean-field model of two coupled interpenetrating antiferromagnetic Heisenberg chains. The extracted values of the exchange integrals are in good agreement with the static magnetic susceptibility data and an earlier spin-wave description of the bound state near the lower boundary of the two-spinon continuum. In addition, there is clear evidence for a four-spinon continuum at high energies.
Collapse
Affiliation(s)
- M Enderle
- Institut Laue Langevin, BP156, 6 rue Horowitz, 38042 Grenoble, France
| | | | | | | | | | | |
Collapse
|
20
|
Murani AP, Severing A, Enderle M, Steffens P, Richard D. Possible anisotropic s--f hybridization in a cubic heavy-fermion compound: CeIn1Sn2. Phys Rev Lett 2008; 101:206405. [PMID: 19113363 DOI: 10.1103/physrevlett.101.206405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Indexed: 05/27/2023]
Abstract
Polarized neutron scattering measurements on a single crystal of composition CeIn1Sn2 show a broad, single-ion, spectral response centered on a characteristic energy of approximately 9+/-1 meV at the zone boundary point (0 0 1.5). The zone center spectral response is closely similar in form but has a slightly reduced amplitude, smaller by some 20%. Constant-omega scans show that these intensity modulations, of amplitude approximately 10%, resembling intersite antiferromagnetic correlations, are superimposed on a mean variation that follows the Ce3+, 4f;{1}, single-ion form factor, and are tentatively attributed to q-dependent hybridization of the localized 4f state with the conduction electrons.
Collapse
Affiliation(s)
- A P Murani
- Institut Laue Langevin, 6 Rue Jules Horowitz BP 156, F-38042 Grenoble Cedex 9, France
| | | | | | | | | |
Collapse
|
21
|
Franke KJ, Nilius G, Rühle K, Fischer K, Enderle M. Experimentelle Untersuchungen zur Kryoextraktion. Pneumologie 2008. [DOI: 10.1055/s-2008-1074219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
22
|
Stockert O, Enderle M, Löhneysen HV. Magnetic fluctuations at a field-induced quantum phase transition. Phys Rev Lett 2007; 99:237203. [PMID: 18233405 DOI: 10.1103/physrevlett.99.237203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Indexed: 05/25/2023]
Abstract
We report an inelastic neutron-scattering study at the field-induced magnetic quantum phase transition of CeCu5.8Au0.2. The data can be described better by the spin-density-wave scenario than by a local quantum critical point, while the latter scenario was shown to be applicable to the zero-field concentration-tuned quantum phase transition in CeCu6-xAux for x=0.1. This constitutes direct microscopic evidence for a difference in the quantum fluctuation spectra at a magnetic quantum critical point driven by different tuning parameters.
Collapse
Affiliation(s)
- O Stockert
- Max-Planck-Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany
| | | | | |
Collapse
|
23
|
Christensen NB, Rønnow HM, McMorrow DF, Harrison A, Perring TG, Enderle M, Coldea R, Regnault LP, Aeppli G. Quantum dynamics and entanglement of spins on a square lattice. Proc Natl Acad Sci U S A 2007; 104:15264-9. [PMID: 17884986 PMCID: PMC2000527 DOI: 10.1073/pnas.0703293104] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bulk magnetism in solids is fundamentally quantum mechanical in nature. Yet in many situations, including our everyday encounters with magnetic materials, quantum effects are masked, and it often suffices to think of magnetism in terms of the interaction between classical dipole moments. Whereas this intuition generally holds for ferromagnets, even as the size of the magnetic moment is reduced to that of a single electron spin (the quantum limit), it breaks down spectacularly for antiferromagnets, particularly in low dimensions. Considerable theoretical and experimental progress has been made in understanding quantum effects in one-dimensional quantum antiferromagnets, but a complete experimental description of even simple two-dimensional antiferromagnets is lacking. Here we describe a comprehensive set of neutron scattering measurements that reveal a non-spin-wave continuum and strong quantum effects, suggesting entanglement of spins at short distances in the simplest of all two-dimensional quantum antiferromagnets, the square lattice Heisenberg system.
Collapse
Affiliation(s)
- N B Christensen
- Materials Research Department, Risø National Laboratory, Technical University of Denmark, DK-4000 Roskilde, Denmark.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Christensen NB, Rønnow HM, Mesot J, Ewings RA, Momono N, Oda M, Ido M, Enderle M, McMorrow DF, Boothroyd AT. Nature of the magnetic order in the charge-ordered cuprate La1.48Nd0.4Sr0.12CuO4. Phys Rev Lett 2007; 98:197003. [PMID: 17677652 DOI: 10.1103/physrevlett.98.197003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Indexed: 05/16/2023]
Abstract
Using polarized neutron scattering we establish that the magnetic order in La(1.48)Nd(0.4)Sr(0.12)CuO(4) is either (i) one dimensionally modulated and collinear, consistent with the stripe model or (ii) two dimensionally modulated with a novel noncollinear structure. The measurements rule out a number of alternative models characterized by 2D electronic order or 1D helical spin order. The low-energy spin excitations are found to be primarily transversely polarized relative to the stripe ordered state, consistent with conventional spin waves.
Collapse
Affiliation(s)
- N B Christensen
- Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Chang J, Schnyder AP, Gilardi R, Rønnow HM, Pailhes S, Christensen NB, Niedermayer C, McMorrow DF, Hiess A, Stunault A, Enderle M, Lake B, Sobolev O, Momono N, Oda M, Ido M, Mudry C, Mesot J. Magnetic-field-induced spin excitations and renormalized spin gap of the underdoped La1.895Sr0.105CuO4 superconductor. Phys Rev Lett 2007; 98:077004. [PMID: 17359052 DOI: 10.1103/physrevlett.98.077004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Indexed: 05/14/2023]
Abstract
High-resolution neutron inelastic scattering experiments in applied magnetic fields have been performed on La1.895Sr0.105CuO4 (LSCO). In zero field, the temperature dependence of the low-energy peak intensity at the incommensurate momentum transfer QIC=(0.5,0.5+/-delta,0),(0.5+/-delta,0.5,0) exhibits an anomaly at the superconducting Tc which broadens and shifts to lower temperature upon the application of a magnetic field along the c axis. A field-induced enhancement of the spectral weight is observed, but only at finite energy transfers and in an intermediate temperature range. These observations establish the opening of a strongly downward renormalized spin gap in the underdoped regime of LSCO. This behavior contrasts with the observed doping dependence of most electronic energy features.
Collapse
Affiliation(s)
- J Chang
- Laboratory for Neutron Scattering, ETH Zurich and PSI Villigen, CH-5232 Villigen PSI, Switzerland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Kaehler GFBA, Sold MG, Fischer K, Post S, Enderle M. Selective fluid cushion in the submucosal layer by water jet: advantage for endoscopic mucosal resection. Eur Surg Res 2007; 39:93-7. [PMID: 17299266 DOI: 10.1159/000099597] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 11/24/2006] [Indexed: 12/15/2022]
Abstract
BACKGROUND/AIM Numerous new techniques have recently been reported and described for the endoscopic mucosal resection of large superficial lesions of the gastrointestinal tract. We present here for the first time the application of a water jet dissector for mucosa elevation. MATERIALS AND METHODS In an ex vivo study, the effectiveness of a water jet dissector (Helix Hydro-Jet) placed directly on the stomach walls of 8 pigs was examined to create a mucosal elevation. After having determined optimal pressures, angle of application, and application times, 13 submucosal fluid cushions were produced in different areas of the stomach walls of 8 pigs in vivo, and the sizes of the resulting submucosal cushions were measured. RESULTS Using pressures between 30 and 70 bar, it was routinely possible to create submucosal fluid cushions in the stomach wall ex vivo as well as in vivo. Histological examination showed a selective edema in the submucosa without damage to the deeper mucosal layers of the gastric wall. CONCLUSIONS The capacity of a targeted high-pressure water jet to penetrate the mucosa and selectively create a fluid cushion in the submucosa facilitates endoscopic resection of the mucosa. This new method could contribute to ameliorate the endoscopic treatment of mucosal tumors which previously could not be resected endoscopically due to their size, extent, or location.
Collapse
Affiliation(s)
- G F B A Kaehler
- Department of Surgery, University Hospital Mannheim, Ruprecht-Karls University Heidelberg, Mannheim, Germany.
| | | | | | | | | |
Collapse
|
27
|
Figge A, Heusch M, Lemloh A, Wiegratz A, Enderle M, Schmiegel W, Calabrese P. Hat die kognitive Leistungsfähigkeit von Diabetikern einen Einfluss auf den Schulungserfolg? Akt Neurol 2007. [DOI: 10.1055/s-2007-987959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
28
|
Reichle G, Esselmann B, Pobloth A, Schäller D, Fischer K, Enderle M, Freitag L. Argonplasmakoagulation (APC) mit Argon „Preflow“ in der interventionellen Bronchoskopie. Ein neues Verfahren zur Reduktion der Brandgefahr bei Patienten mit respiratorischer Insuffizienz oder Atemwegs-Stent. Pneumologie 2007. [DOI: 10.1055/s-2007-973235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
29
|
Balletshofer BM, Goebbel S, Rittig K, Enderle M, Schmölzer I, Wascher TC, Ferenc Pap A, Westermeier T, Petzinna D, Matthaei S, Häring HU. Intense cholesterol lowering therapy with a HMG-CoA reductase inhibitor does not improve nitric oxide dependent endothelial function in type-2-diabetes--a multicenter, randomised, double-blind, three-arm placebo-controlled clinical trial. Exp Clin Endocrinol Diabetes 2005; 113:324-30. [PMID: 15977099 DOI: 10.1055/s-2005-865642] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Disturbances in nitric oxide (NO) metabolism resulting in endothelial dysfunction play a central role in the pathogenesis of atherosclerosis in hypercholesterolemia and in individuals with type 2 diabetes. It is unclear whether lipid lowering therapy with HMG-CoA-reductase inhibitors might improve endothelial function in subjects with type 2 diabetes as it is demonstrated in non-diabetic subjects with hypercholesterolemia. We examined the influence of 0.2 mg and 0.8 mg cerivastatin on endothelial function in a multicenter, randomised, double-blind, and three-arm placebo-controlled clinical trial. Endothelial function was assessed by nitric oxide-dependent flow mediated vasodilatation (FMD) of the brachial artery. A total of 103 patients with type 2 diabetes were enrolled in the study. Bayer Company undertook a voluntary action to withdraw cerivastatin from market, therefore the study was terminated earlier. At this point 77 patients were randomised, of which 58 completed the study (mean age 60 +/- 8 years, HbA1c 7.4 +/- 0.9 %). At baseline mean FMD was disturbed in all three therapy arms (5.18 +/- 2.31 % in the placebo group, 3.88 +/- 1.68 in the 0.2-mg cerivastation group, and 4.86 +/- 2.25 in the 0.8-mg cerivastatin group). Despite a significant reduction in cholesterol and LDL-cholesterol-levels after 12 weeks of treatment (decrease in LDL-cholesterol - 26.8 +/- 13.9 % in the 0.2-mg group and - 40.3 +/- 16.0 % in the 0.8-mg group, p = 0.0001, ANCOVA) there was no difference in flow mediated vasodilatation (p = 0.52 and p = 0.56 vs. placebo, respectively, ANCOVA). HbA1c, CRP, and HDL-cholesterol did not change during the study. Furthermore no difference in safety profile between cerivastatin and placebo was found. Despite a significant improvement in lipid profile under statin therapy, no improvement of endothelial dysfunction in terms of nitric oxide bioavailability could be detected.
Collapse
Affiliation(s)
- B M Balletshofer
- Department of Endocrinology and Vascular Medicine, University of Tübingen, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Wascher TC, Schmoelzer I, Wiegratz A, Stuehlinger M, Mueller-Wieland D, Kotzka J, Enderle M. Reduction of postchallenge hyperglycaemia prevents acute endothelial dysfunction in subjects with impaired glucose tolerance. Eur J Clin Invest 2005; 35:551-7. [PMID: 16128861 DOI: 10.1111/j.1365-2362.2005.01550.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVES To investigate whether selective reduction of postchallenge hyperglycaemia influences acute endothelial dysfunction, a very early manifestation of vascular disease, in patients with impaired glucose tolerance. METHODS In a randomized, double-blind, placebo-controlled, cross-over study the acute effect of 200-mg acarbose was investigated in 28 subjects with diagnosed impaired glucose tolerance. Flow-mediated dilation (FMD) of the brachial artery was determined as a measure of endothelial function before and 2 and 3 h after ingestion of 100-g saccharose. Asymmetrical dimethylarginine (ADMA) was measured by high-performance liquid chromatography. RESULTS A negative correlation was observed between the changes of glucose and FMD (r = 0.416, P = 0.0018) 2 h after ingestion of saccharose. At 3 h, neither blood glucose nor FMD were different from baseline. Changes of both blood glucose (P = 0.0007) and FMD (P = 0.046) were significantly lower after administration of acarbose. Subgroup analysis revealed that the effect of acarbose was restricted to those subjects with an increase of blood glucose above the median increase of glycaemia. No changes of plasma ADMA were observed. CONCLUSIONS Our data clearly demonstrate that the postchallenge alteration of vascular function in patients with impaired glucose tolerance is caused by the acute elevation of glycaemia but not mediated by ADMA.
Collapse
Affiliation(s)
- T C Wascher
- Department of Internal Medicine, Medical University of Graz, Austria.
| | | | | | | | | | | | | |
Collapse
|
31
|
Toader AM, Goff JP, Roger M, Shannon N, Stewart JR, Enderle M. Spin correlations in the paramagnetic phase and ring exchange in La2CuO4. Phys Rev Lett 2005; 94:197202. [PMID: 16090204 DOI: 10.1103/physrevlett.94.197202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2005] [Indexed: 05/03/2023]
Abstract
Spin correlations in the paramagnetic phase of La(2)CuO(4) have been studied using polarized neutron scattering, with two important results. First, the temperature dependence of the characteristic energy scale of the fluctuations and the amplitude of the neutron structure factor are shown to be in quantitative agreement with the predictions of the quantum nonlinear sigma model. Second, a comparison of a high-temperature series expansion of the equal-time spin correlations with the diffuse neutron intensity provides definitive experimental evidence for ring exchange.
Collapse
Affiliation(s)
- A M Toader
- Department of Physics, University of Liverpool, Oliver Lodge Laboratory, UK
| | | | | | | | | | | |
Collapse
|
32
|
Bayrakci SP, Mirebeau I, Bourges P, Sidis Y, Enderle M, Mesot J, Chen DP, Lin CT, Keimer B. Magnetic ordering and spin waves in Na0.82CoO2. Phys Rev Lett 2005; 94:157205. [PMID: 15904183 DOI: 10.1103/physrevlett.94.157205] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Indexed: 05/02/2023]
Abstract
NaxCoO2, the parent compound of the recently synthesized superconductor Na(x)CoO(2):yH(2)O, exhibits bulk antiferromagnetic order below approximately 20 K for 0.75</=x</=0.9. We have performed neutron scattering experiments in which we observed Bragg reflections corresponding to A-type antiferromagnetic order in a Na0.82CoO2 single crystal and characterized the corresponding spin-wave dispersions. The spin waves exhibit a strongly energy-dependent linewidth. The in-plane and out-of-plane exchange constants resulting from a fit to a nearest-neighbor Heisenberg model are similar in magnitude, which is unexpected in view of the layered crystal structure of NaxCoO2. Possible implications of these observations are discussed.
Collapse
Affiliation(s)
- S P Bayrakci
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Boothroyd AT, Freeman PG, Prabhakaran D, Hiess A, Enderle M, Kulda J, Altorfer F. Spin correlations among the charge carriers in an ordered stripe phase. Phys Rev Lett 2003; 91:257201. [PMID: 14754145 DOI: 10.1103/physrevlett.91.257201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Indexed: 05/24/2023]
Abstract
We have observed a diffuse component to the low-energy magnetic excitation spectrum of stripe-ordered La(5/3)Sr(1/3)NiO4 probed by neutron inelastic scattering. The diffuse scattering forms a square pattern with sides parallel and perpendicular to the stripe directions. The signal is dispersive, with a maximum energy of approximately 10 meV. Probed at 2 meV, the scattering decreases in strength with increasing temperature, and is barely visible at 100 K. We argue that the signal originates from dynamic, quasi-one-dimensional, antiferromagnetic correlations among the stripe electrons.
Collapse
Affiliation(s)
- A T Boothroyd
- Department of Physics, Oxford University, Oxford, OX1 3PU, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
34
|
Ackermann R, Enderle M. Inversion and suppression of an oxygen bulk phase transition in confined geometry. Eur Phys J E Soft Matter 2003; 12 Suppl 1:S39-S42. [PMID: 15011012 DOI: 10.1140/epjed/e2003-01-010-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2003] [Indexed: 05/24/2023]
Abstract
By means of susceptibility experiments on oxygen confined to the pores of a Gelsil substrate we investigated the bulk gamma- beta transition. At low fillings, the transformation is completely suppressed. At higher but still incomplete filling we observe a partial transformation from gamma to beta on cooling and a subsequent inverted transition on heating, i.e. the transformation of gamma-phase material into the beta-phase upon heating. At 100% filling this inversion disappears. We discuss our results on the basis of geometric considerations.
Collapse
Affiliation(s)
- R Ackermann
- Universität des Saarlandes, Technische Physik, 66123 Saarbrücken, Germany
| | | |
Collapse
|
35
|
Hiltawsky KM, Wiegratz A, Enderle M, Ermert H. [Measurement of flow mediated vasodilation (FMD) using kalman-filtering]. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:557-8. [PMID: 12465235 DOI: 10.1515/bmte.2002.47.s1b.557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Brachial artery flow-mediated vasodilation is increasingly used as a measure of endothelial function. High resolution ultrasound provides a noninvasive method to observe this flow-mediated vasodilation by monitoring the diameter of the artery over time. In the past, the diameter had to be measured in tedious postprocessing routines, usually by the examiner himself. We present a system, which is able to process ultrasound rf-data in realtime. On that system, we implemented a kalman filter, which makes the tracking of both vessel walls possible. The diameter can be calculated accurately, taking into account process noise as well as measurement noise.
Collapse
Affiliation(s)
- K M Hiltawsky
- Institut für Hochfrequenztechnik, Ruhr-Universität Bochum, Deutschland.
| | | | | | | |
Collapse
|
36
|
Noh JD, Rieger H, Enderle M, Knorr K. Critical behavior of the frustrated antiferromagnetic six-state clock model on a triangular lattice. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 66:026111. [PMID: 12241241 DOI: 10.1103/physreve.66.026111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2002] [Indexed: 05/23/2023]
Abstract
We study the antiferromagnetic six-state clock model with nearest neighbor interactions on a triangular lattice with extensive Monte Carlo simulations. We find clear indications of two phase transitions at two different temperatures: Below T(I) a chirality order sets in and by a thorough finite-size-scaling analysis of the specific heat and the chirality correlation length we show that this transition is in the Ising universality class (with a nonvanishing chirality order parameter below T(I)). At T(KT) (<T(I)) the spin-spin correlation length as well as the spin susceptibility diverges according to a Kosterlitz-Thouless (KT) form and spin correlations decay algebraically below T(KT). We compare our results to recent x-ray diffraction experiments on the orientational ordering of CF3Br monolayers physisorbed on graphite. We argue that the six-state clock model describes the universal feature of the phase transition in the experimental system and that the orientational ordering belongs to the KT universality class.
Collapse
Affiliation(s)
- J D Noh
- Theoretische Physik, Universität des Saarlandes, 66041 Saarbrücken, Germany
| | | | | | | |
Collapse
|
37
|
Enderle M, Rønnow HM, McMorrow DF, Regnault LP, Dhalenne G, Revcholevschi A, Vorderwisch P, Schneider H, Smeibidl P, Meissner M. Excitations of the field-induced quantum soliton lattice in CuGeO(3). Phys Rev Lett 2001; 87:177203. [PMID: 11690306 DOI: 10.1103/physrevlett.87.177203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2000] [Indexed: 05/23/2023]
Abstract
The incommensurate magnetic soliton lattice in the high-field phase of a spin-Peierls system results from quantum fluctuations. We have used neutron scattering techniques to study CuGeO(3), allowing us to obtain the first complete characterization of the excitations of the soliton lattice. Three distinct excitation branches are observed, all of which are gapped. The two highest energy modes have minimum gaps at the commensurate wave vector and correspond to the creation or annihilation of soliton pairs. The third mode is incommensurate and is discussed in relation to theoretical predictions.
Collapse
Affiliation(s)
- M Enderle
- Technische Physik, Universität des Saarlandes, 66123 Saarbrücken, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Balletshofer BM, Goebbel S, Rittig K, Lehn-Stefan A, Renn W, Enderle M, Dietz K, Häring HU. [Influence of experience on intra- and interindividual variability in assessing peripheral endothelial dysfunction with high resolution ultrasound]. Ultraschall Med 2001; 22:231-235. [PMID: 11607892 DOI: 10.1055/s-2001-17894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
UNLABELLED The non-invasive evaluation of endothelial dysfunction with high-resolution ultrasound has become a widely accepted tool in determination of high-risk subjects for early atherosclerosis. Furthermore it is often used as intermediate outcome in intervention studies. AIM We examined the influence of examiner experience on intra- and inter-individual variability in the measurement of flow-associated vasodilation (FAD) independent of automated analysis systems. METHOD FAD was measured on two occasions in 7 and 8 subjects respectively (mean age 32 +/- 3 years) by two investigators after different prior training procedures with a 13 MHz linear transducer (LA14A, ESAOTE Biomedica). RESULTS The intra-individual variability expressed as median absolute difference in the measurements of FAD was 1.1 % (range from 0.03 % to 3.2 %) for examiner one with an experience of more than 50 FAD measurements through former studies and 2.9 % (range from 1.6 % to 9.2 %) for examiner two with only 10 training examinations under supervision. By a further training period of two months, with an increase of examinations of additional 20 measurements by both examiners, the intra-observer variability could be dropped to 0.9 % (range from 0.03 % to 1.3 %) for examiner two (p = 0.0025) with no significant change for examiner one (median 0.6 % with a range from 0.14 % to 3.7 %). As expected, the inter-individual variability was not influenced by this further training (median 1.0 % with a range of 0.5 % to 3.6 % versus a median of 1.6 % with a range from 0.15 % to 7.5 %). CONCLUSION 30 training measurements of FAD under supervision should be regarded as minimum requirement for valid determination of endothelial function. The reachable result for the intra-observer variability is thereby within the range of computed analysis systems.
Collapse
Affiliation(s)
- B M Balletshofer
- Abteilung für Endokrinologie und vaskuläre Medizin, Universität Tübingen.
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Kenzelmann M, Cowley RA, Buyers WJ, Coldea R, Gardner JS, Enderle M, McMorrow DF, Bennington SM. Multiparticle states in the S = 1 chain system CsNiCl3. Phys Rev Lett 2001; 87:017201. [PMID: 11461492 DOI: 10.1103/physrevlett.87.017201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2000] [Indexed: 05/23/2023]
Abstract
A continuum of magnetic states has been observed by neutron scattering from the spin-1 chain compound CsNiCl3 in its disordered gapped one-dimensional phase. Results using both triple-axis and time-of-flight spectrometers show that around the antiferromagnetic point Qc = pi, the continuum lies higher in energy than the Haldane gapped excitations. At 6 K the integrated intensity of the continuum is about 12(2)% of the total spectral weight. This result is considerably larger than the 1%-3% weight predicted by the nonlinear sigma model for the three-particle continuum.
Collapse
Affiliation(s)
- M Kenzelmann
- Oxford Physics, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Rønnow HM, Enderle M, McMorrow DF, Regnault LP. The field induced soliton lattice in CuGeO. Acta Crystallogr A 2000. [DOI: 10.1107/s010876730002362x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
|
41
|
Ronnow HM, Enderle M, McMorrow DF, Regnault L, Dhalenne G, Revcolevschi A, Hoser A, Prokes K, Vorderwisch P, Schneider H. Neutron scattering study of the field-induced soliton lattice in CuGeO3. Phys Rev Lett 2000; 84:4469-4472. [PMID: 10990713 DOI: 10.1103/physrevlett.84.4469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/1999] [Indexed: 05/23/2023]
Abstract
CuGeO3 undergoes a transition from a spin-Peierls phase to an incommensurate phase at a critical field of H(c) approximately 12.5 T. In the high-field phase a lattice of solitons forms, with both structural and magnetic components, and these have been studied using neutron scattering techniques. Our results provide direct evidence for a long-ranged magnetic soliton structure which has both staggered and uniform magnetizations with amplitudes that are broadly in accord with theoretical estimates. The magnetic soliton width gamma(m) and the field dependence of the incommensurability deltak(SP) are found to agree well with theoretical predictions.
Collapse
Affiliation(s)
- HM Ronnow
- Condensed Matter Physics and Chemistry Department, Riso National Laboratory, DK-4000 Roskilde, Denmark
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Coerper S, Schäffer M, Enderle M, Schott U, Köveker G, Becker HD. [The wound care center in surgery: an interdisciplinary concept for diagnostic and treatment of chronic wounds]. Chirurg 1999; 70:480-4. [PMID: 10354850 DOI: 10.1007/s001040050676] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In Germany there is no standardized wound care for patients with chronic wounds in specialized centers. We have established a wound care unit for the past 6 years. The principal concept of therapy was characterized by standardized local surgery, moist wound dressings and concomitant treatment of the underlying disease. We performed local therapy, coordinated the interdisciplinary treatment and developed a new wound documentation system for quality control. We established a close network, integrating general practitioners and home care organizations to realize a mainly outpatient treatment supported by short hospital therapy. Exclusive outpatient treatment was performed in 42% of all patients. According to our prospective data, we achieved an improvement in wound care: 69% of the wounds resistant to therapy for a mean of 30 months healed within 12 months after therapy according to our protocol. Our data strongly supported the importance of local surgery: neither wound depth nor wound infection had any influence on the healing rate, presumably due to radical excisional debridement of necrotic tissue. The presented data justify on medical and economic grounds the establishment of such wound care centers in Germany.
Collapse
Affiliation(s)
- S Coerper
- Abteilung für Allgemeine Chirurgie und Poliklinik, Universitätsklinik Tübingen.
| | | | | | | | | | | |
Collapse
|
43
|
Schroeder S, Enderle M, Osson R, Baumbach A, Hordeg C, Ptehl M, Haase K, Haering H, Karsch K. The determination of peripheral flow mediated vasodilation is a sensitive and specific predictor for the presence of coronary artery disease. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)82038-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
44
|
Koch M, Pfohl M, Enderle M, Schnauder G, Seif FJ. Detection of the apolipoprotein B-100 arg(3500) > gl mutation in familial defective apoB-100 by temperature-gradient gel electrophoresis. Z Gastroenterol 1996; 34 Suppl 3:16-8. [PMID: 8767448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Familial defective apolipoprotein B-100 (FDB) is caused by a point mutation in exon 26 of the apolipoprotein B gene leading to a decreased binding to the LDL-receptor. Patients with FDB have hypercholesterolemia and atherosclerotic disease. Since other mutations of apoB-100 could also cause binding abnormalities we established a temperature-gradient gel electrophoresis (TGGE) method and started to screen hypercholesterolemic patients for the presence of point mutations in this region. 4 of 43 patients were positive according to TGGE and subsequent sequencing showed the familiar guanine to adenine transition in codon 3500 in all cases.
Collapse
Affiliation(s)
- M Koch
- Abt. IV, Endokrinologie, Universität Tübingen
| | | | | | | | | |
Collapse
|
45
|
Hutcheson DP, Kay M, Enderle M, Francis R, Luckey T. The kinetics of lanthanide oxide markers in the alimentary tract of the pig. Nutr Res 1983. [DOI: 10.1016/s0271-5317(83)80043-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|