Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

"Online First" included
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32337 Publications
Magnetic properties of ion implanted diamond
Höhne, R.; Esquinazi, P.; Heera, V.; Weishart, H.;
Single crystalline diamond samples of type IIa were implanted with boron and CVD diamond samples with fluorine or iron ions. Defect rich surface layers extending to a depth of about 300 nm for boron and 1 μm for fluorine and iron were produced by multiple energy implantation. The ion concentrations at the implanted regions were between 30 and 600 ppm for iron and fluorine and 0.5 to 1.5 at.% for boron. In all samples the magnetic properties were dominated by the diamagnetism of pure diamond. The main influence of iron and fluorine implantation on the magnetic properties of diamond is the creation of paramagnetic centres induced by disorder. Whereas diamond implanted with boron at a temperature of 900 °C does not show detectable paramagnetism. After subtraction of the linear background all implanted samples show small ferromagnetic-like loops. Although these signals are clearly above the detection limit and appear to be caused by ferromagnetism, we show that the measured loops are mainly caused by a SQUID artefact. We did not find any evidence for the existence of superconductivity in boron-doped diamond samples prepared under the used conditions.
Keywords: Diamond; Ion implantation; Magnetic properties; Irradiation effects

Publ.-Id: 10143 - Permalink

Confinement of paramagnetic ions under magnetic field influence: Lorentz- versus concentration gradient force based explanations
Weier, T.; Eckert, K.; Mühlenhoff, S.; Cierpka, C.; Bund, A.; Uhlemann, M.;
Concentration variations observed at circular electrodes with their axis parallel to a magnetic and normal to the gravitational field have previously been attributed elsewhere to the concentration gradient force only. The present paper aims to show that Lorentz force driven convection is a more likely explanation.
Keywords: magnetoelectrochemistry, Lorentz force, concentration gradient force, particle image velocimetry, synthetic schlieren, interferometry

Publ.-Id: 10142 - Permalink

Liquid Metal Magnetohydrodynamics – astrophysical relevance and engineering applications
Gerbeth, G.; Grants, I.; Gundrum, T.; Stefani, F.;
Magnetic fields influence the motion of liquid metals, but the melt motion modifies magnetic field distributions as well. Eventually, melt motions are able to create a magnetic field, known as the dynamo effect.
We present various laboratory experiments demonstrating this interaction between the flow and magnetic fields.
  • Lecture (Conference)
    Fifth International Conference on Fluid Mechanics, 15.-19.08.2007, Shanghai, China
  • Contribution to external collection
    F.G. Zhuang, J.C. Li: New Trends in Fluid Mechanics Research, Peking: Tsinghua-Springer, 2007, 690-693

Publ.-Id: 10141 - Permalink

Projective Hilbert space structures at exceptional points and their extension to line bundles over spectral Riemann surfaces
Günther, U.; Rotter, I.; Samsonov, B.;
A non-Hermitian complex symmetric 2×2 matrix toy model is used to study projective Hilbert space structures in the vicinity of exceptional points (EPs). The bi-orthogonal eigenvectors of a diagonalizable matrix are Puiseux-expanded in terms of the root vectors at the EP. It is shown that the apparent contradiction between the two incompatible normalization conditions with finite and singular behavior in the EP-limit can be resolved by projectively extending the original Hilbert space. The complementary normalization conditions correspond then to two different affine charts of this enlarged projective Hilbert space. Geometric phase and phase jump behavior are analyzed and the usefulness of the phase rigidity as measure for the distance to EP configurations is demonstrated. The EP-related quantum brachistochrone problem of PT-symmetrically extended Quantum Mechanics is discussed. Finally, aspects of a smooth globally defined line bundle structure over spectral Riemann surfaces are sketched.

The talk is partially based on arXiv:0704.1291v2 [math-ph] and includes newer findings going beyond this e-print.
Keywords: exceptional points, branch points, projective Hilbert space, geometric phase, singularities, PT-symmetric Quantum Mechanics, quantum brachistochrone problem, spectral Riemann surface, line bundle
  • Invited lecture (Conferences)
    Analytic and algebraic methods III, 19.06.2007, Prague, Czech Republic

Publ.-Id: 10140 - Permalink

On the interaction of molecular hydrogen with diamonds: An experimental study using nuclear probes and thermal desorption
Shiryaev, A. A.; Grambole, D.; Rivera, A.; Herrmann, F.;
Hydrogen behavior in monocrystalline diamonds with different concentrations and types of nitrogen defects was studied using Nuclear Reaction and micro-Elastic Recoil Detection Analyses and Thermal Desorption Spectroscopy. Diamonds were studied in as-received state, after HPHT treatment and after hydrogenation in molecular hydrogen. A considerable amount of hydrogen was found to be bonded to diamond surfaces. Kinetics of surface hydrogen desorption is similar to what was reported for plasma-hydrogenated diamonds. The solubility of hydrogen in type IIa diamonds is very low. The efficiency of hydrogen traps in diamond bulk varies with the dominant type of nitrogen-related defects. The cross-section of traps decreases in row Ib > IaA > IaB diamonds, though binding energy in type IaB crystals may be higher, than in type IaA. Dislocations may promote hydrogen diffusion. A marked dependency of the hydrogen content and diffusivity between diamond growth sectors were observed for some samples. The total hydrogen content is higher in octahedral sectors.
Keywords: Diamond crystal; Diffusion; Defect characterization; Hydrogen
  • Diamond and Related Materials 16(2007), 1479-1485

Publ.-Id: 10139 - Permalink

Effects of radiation damage in minerals on their electron back-scatter coefficient
Nasdala, L.; Kronz, A.; Tichomirowa, M.; Grambole, D.; Trullenque, G.;
The structural state (i.e., order-disorder) of minerals and other solids analyzed in an electron microprobe or scanning electron microscope may notably affect the back-scattering of incident beam electrons. Structural heterogeneity, as it is commonly observed in radiation-damaged minerals, may thus contribute to signal intensity variations in back-scattered electron (BSE) images. Such structural BSE effects are easily overlooked because they may be insignificant in cases of minerals with high internal Z contrast. Correspondingly, it has generally been assumed that BSE images of single-crystals of minerals are mainly controlled by the sample’s chemical heterogeneity. However, structural heterogeneity cannot be neglected in the discussion of BSE images; this is especially the case if crystals only show minor Z variations.
We show with two examples that radiation damage (i.e., gradual to complete destruction of the crystal lattice) results in a significant increase of the back-scatter coefficient. The phenomenon is assigned to lowered penetration depths of electrons and thus related to electron channelling contrast. The BSE of natural zircon crystals is in most cases predominantly controlled by radiation damage. Annealing studies revealed that after structural reconstitution, the BSE intensity is notably decreased and much more uniform, in spite of the same chemical heterogeneity (especially concentrations of Hf and U) as before the treatment. As an even more unambiguous example we present observations on irradiation-damaged silicon. Damage up to complete amorphization was produced upon implantation of Si ions. Consequently there are no chemical variations and no Z contrast in this case. Examples show that the degree of structural damage needs to be considered in the discussion and interpretation of BSE images of radiation-damaged minerals.
  • Lecture (Conference)
    Frontiers in Mineral Sciences, 26.-28.06.2007, Cambridge, UK
  • Contribution to proceedings
    Frontiers in Mineral Sciences, 26.-28.06.2007, Cambridge, UK
    Programme and Abstracts, 85-86

Publ.-Id: 10138 - Permalink

Raman study of irradiation damage in silicon
Nasdala, L.; Grambole, D.;
We have studied irradiation damage in a single-crystal silicon wafer prepared parallel to (100) by micro-Raman spectroscopy. Surficial structural damage in areas ~150 µm in size was produced by irradiation with a microbeam loaded with 600 keV Si+ ions at a 3MV Tandetron accelerator, Rossendorf (GRAMBOLE et al., 2007). Several implantations were done with a uniform fluence of 5 × 1014 cm-2, however, at different temperatures to produce areas with different degrees of damage. Full amorphisation was reached at implantation temperatures below 140 °C (NASDALA et al., 2007). Monte Carlo simulations using the SRIM code (ZIEGLER et al., 1985) predict that trajectory lengths of implanted ions are below 1 µm. This still exceeds the low penetration depth of light in silicon and, with that, the depth probed by Raman spectroscopy. Spectra obtained from partially amorphised areas virtually consist of an overlap of the two Raman spectra of amorphous and crystalline silicon, i.e., the LO=TO band of crystalline silicon at ~ 521 cm-1 shows only minor band broadening and shift when compared to the spectrum of the unirradiated host wafer. This indicates that the majority of the structural damage is located in amorphous clusters whereas the remnant crystalline silicon fraction shows only low levels of point defects as caused by atomic displacements.

GRAMBOLE, D., HERRMANN, F., HEERA, V. & MEIJER, J. (2007): Nucl. Instr. Meth. Phys. Res. B (in press).
NASDALA, L., GRAMBOLE, D., KRONZ, A. & TRULLENQUE, G. (2007): Am. Mineral. (accepted).
ZIEGLER, J. F., BIERSACK, J. P. & LITTMARK. U. (1985): The Stopping and Range of Ions in Solids.
Pergamon, New York.
  • Lecture (Conference)
    MinPet 2007 - Tagung der Österreichischen Mineralogischen Gesellschaft gemeinsam mit dem Geologischen Dienst der Autonomen Provinz Bozen, 16.-21.09.2007, Meran, Italy
  • Open Access LogoAbstract in refereed journal
    Mitteilungen der Österreichischen Mineralogischen Gesellschaft 153(2007), 85

Publ.-Id: 10137 - Permalink

Formung von Ge Nanopartikeln mit MeV Ionen
Schmidt, B.;
The deformation of Ge-nancrystals embedded in SiO2 during high energy ion irradiation has been investigated. For this purpose 200 nm thermally grown SiO2 was covered with a 5 nm Ge layer and a 100 nm SiO2 top layer by sputter deposition. Subsequent thermal annealing at 950 °C for 300s transformed the embedded continuous Ge layer through spinodal dewetting into Ge nanocrystals with a mean diameter of 20 nm. Afterwards, the Ge nanocrystals buried in SiO2 were irradiated at room temperature with 38 MeV I7+ ions in the dose range (1-4)x1015 cm-2. The ion current density was 40 nA/cm2. Cross-section TEM investigation of the irradiated samples showed that under given irradiation conditions the spherical Ge nanocrystal were shaped mainly into oblate-like Ge particles, which are in the amorphous state. As a result of the investigations we conclude that Ge nanoparticles embedded in SiO2 show the same form transformation behaviour under ion irradiation as irradiated amorphous silica colloides, namely, an expansion perpendicular to the ion beam direction and a contraction parallel to the ion beam direction. Mechanisms of the observed ion beam induced anisotropic deformation of Ge nanoparticles are discussed.
Keywords: heavy ion irradiation, ion beam shaping, nanoparticles
  • Lecture (Conference)
    Workshop Ionenstrahlphysik und Nanotechnologie, 10.-11.05.2007, Bochum, Germany

Publ.-Id: 10136 - Permalink

Fabrication of nanostructures by FIB: cobalt disilicide nanowires in silicon
Schmidt, B.;
In the introduction of the talk the Rossendorf FIB tool and the application possibilities in nanofabrication will be described.
The main part of the contribution is focused on cobalt FIB ion beam synthesis of CoSi2 nanowires with feature dimensions of about 20-50 nm in diameter and wire lengths of some µm. Using the Rossendorf FIB equipped with a CANION 31Mplus FIB column (Orsay Physics) a focusing of the Co++ ion beam down to a spot diameter of 30-50 nm was achieved. The ion energy was chosen to be 60 keV corresponding to a mean ion penetration depth of Rp = 53 nm. For the study of the conventional ion beam synthesis of CoSi2 nanowires (phase separation through precipitation and wire ripening during thermal treatment) and their decay into chains of nanoparticles due to nanowire instabilities the samples were implanted with high doses (1x1016-2x1017 cm-2) and at 420 °C sample temperature. Additionally, the scan direction of the FIB relative to the crystal directions was varied (normal FIB scan-direction was parallel to the [110]-direction on the Si surface). Small misalignment of the FIB trace relative to the [110] orientations leads to the decay of the CoSi2 nanowires into chains of more or less prolonged CoSi2 nanoparticles. Samples implanted at lower ion doses (1014-1016 cm-2) and at room temperature were used to investigate the influence of locally FIB induced irradiation defects on the CoSi2 nanowire growth. In this case, nanowires were again formed during thermal treatment by reacting of cobalt from a thin evaporated layer on the sample back side with defects induced by Co+ ion implantation with the FIB. The nanowires here are self-aligned along the in-plane [110] silicon crystal directions in (001)- and (111)-Si. In contrast to conventional ion beam synthesis of CoSi2 nanowires by high dose FIB implantation along a narrow trace defect-induced and self-aligned nanowire growth seems to be more stable.
Finally, in the outlook some examples of FIB based fabrication of nanostructures for different applications (e.g. 3D-nanostructures) will be discussed.
Keywords: Focused ion beam, ion beam synthesis, nanowires
  • Invited lecture (Conferences)
    Ion Beam Nanofabrication, NANO 2007 AAMU/Huntsville Nanotechnology Meeting, 21.-22.05.2007, Huntsville, Alabama, USA

Publ.-Id: 10135 - Permalink

Mikro-PET-Untersuchungen zu Bioverteilung und Metabolismus von F-18-fluorbenzoylierten Aminosäuren und Dipeptiden in den Nieren
Hultsch, C.; Wüst, F.; Pawelke, B.; Bergmann, R.;
kein Abstract verfügbar
  • Lecture (Conference)
    42. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 21.-24.04.2004, Rostock, Germany

Publ.-Id: 10134 - Permalink

Technetium-Fettsäuren (TcFS): Synthesen und biologische Evaluierung von 99mTc-markierten Fettsäuren für die Anwendung in Herzstoffwechsel-Untersuchungen
Walther, M.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Ruhr-Universität Bochum, 27.-28.03.2006, Bochum, Germany

Publ.-Id: 10133 - Permalink

Characterization of Pyoverdins Secreted by a Subsurface Strain of Pseudomonas fluorescens and Their Interactions with Uranium(VI)
Moll, H.; Glorius, M.; Bernhard, G.; Johnsson, A.; Pedersen, K.; Schäfer, M.; Budzikiewicz, H.;
Fluorescent Pseudomonas species secrete pyoverdin-type siderophores with a high potential to dissolve, bind, and thus transport uranium in the environment. The formation of complexes of UO22+ with pyoverdins released by the groundwater bacterium Pseudomonas fluorescens (CCUG 32456) isolated at a depth of 70 m depth in the Äspö Hard Rock Laboratory, Sweden, was studied. Mass spectrometry indicated that the cells produce a pyoverdinmixture with four main components: pyoverdin with a succinamide side chain, pyoverdin with a succinic acid side chain, ferribactin with a succinamide side chain, and ferribactin with a glutamic acid side chain. Three pK values could be determined from the pH-dependent changes in the absorption spectra of the pyoverdin mixture: log ß012 = 22.67 ± 0.15 (pK1 = 4.40), log ß013 = 29.15 ± 0.05 (pK2 = 6.48), and log ß014 = 33.55 ± 0.05 (pK3 = 10.47). The fluorescence properties of the pyoverdin mixture were pH dependent. The emission maximum changed from 448 nm at pH = 2.1 to 466 nm in the pH3.88.9 range. At pH > 4 a mono-exponential fluorescence decay dominates with a decay time of 5865 ± 640 ps. A drastic change in the intrinsic fluorescence properties, e.g., static fluorescence quenching, occurred due to the complex formation with UO22+. Species containing UO22+ of the type MpLqHr were identified from the dependencies observed in the ultraviolet visible and time-resolved laser-induced fluorescence spectroscopy spectra at pyoverdin concentrations below 0.1 mM. The following average formation constants were determined: log β112 = 30.00 ± 0.64 and log β111 = 26.00 ± 0.85 at ionic strength I = 0.1 M (NaClO4). The determined stability constants can be used directly in safety calculations of the mobilizing effect of released pyoverdins on uranium, in uranium-contaminated environments such as mine waste disposal sites.
Keywords: Uranyl, Pyoverdins, UV-vis spectra, fs-TRLFS spectra, Complexation

Publ.-Id: 10131 - Permalink

Positronen-Emissions-Tomographie (PET): Wie radioaktive Substanzen den Körper biochemisch transparent machen.
Wüst, F.;
kein Abstract verfügbar
  • Lecture (others)
    Lange Nacht der Wissenschaften, 30.06.2006, Dresden, Germany

Publ.-Id: 10130 - Permalink

Radiopharmaka-Herstellung/Manufacturing of radiophatrmaceuticals
Füchtner, F.; Zessin, J.; Preusche, S.; Steinbach, J.;
kein Abstract verfügbar
  • Contribution to HZDR-Annual report
    Wissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-469 April 2007, 48-51


Publ.-Id: 10129 - Permalink

[18F]Fluoracetat: Vom Gift zum PET-Tracer [18F]Fluoroacetate: From toxin to PET-tracer
Bergmann, R.; Richter, S.; Pietzsch, J.; Wüst, F.;
kein Abstract verfügbar
  • Contribution to HZDR-Annual report
    Wissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-469 April 2007, 36-38


Publ.-Id: 10128 - Permalink

Radioaktive Metalle für die Tumortherapie
Pietzsch, H.-J.; Stephan, H.; Steinbach, J.;
kein Abstract verfügbar
  • Contribution to HZDR-Annual report
    Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-451 März 2006, 19-22


Publ.-Id: 10127 - Permalink

PET-Bilder – scharf gemacht
Bühler, P.; Just, U.; Möckel, D.; Langner, J.; van den Hoff, J.;
kein Abstract verfügbar
  • Contribution to HZDR-Annual report
    Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-421 März 2005, 20-21


Publ.-Id: 10126 - Permalink

Strain profile of (001) silicon implanted with nitrogen by plasma immersion
Diaz, B.; Abramof, E.; Castro, R. M.; Ueda, M.; Reuther, H.;
In this work, we investigate the strain and defect state of silicon implanted with nitrogen by plasma immersion ion implantation, with doses between 4.5 1016 and 8.7 1016 cm 2. For this purpose, we have used Auger electron spectroscopy, x-ray reflectivity, and high-resolution x-ray diffraction. Auger spectra showed that nitrogen concentration profiles broaden and shift deeper into the substrate as the dose increases. High oxygen concentration in the first 20 nm suggested the presence of an amorphous oxide layer at the sample surface, which was confirmed by x-ray reflectivity measurements. Reciprocal space maps revealed a tensile strain perpendicular to the surface, while no in-plane strain was detected. Since no significant diffuse scattering was found, randomly distributed point defects must be predominant in the strained region compared to large displacement field defects such as clusters and dislocations. 2 scans around (004) Bragg reflection were fitted using dynamical theory of x-ray diffraction. The strain profiles obtained from the best fits correlated well with nitrogen concentration depth profiles, signaling interstitial nitrogen as the main source of strain.
  • Journal of Applied Physics 101(2007), 103523

Publ.-Id: 10125 - Permalink

Vom Radioiod zum molekularen Imaging: Potential und Grenzen der Radiopharmazie
Steinbach, J.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Fachforum der Hanns-Seidel-Stiftung, 27.-29.10.2006, Kolster Banz, Germany

Publ.-Id: 10124 - Permalink

Radiopharmaceutical research at Saxony - an overview
Steinbach, J.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    General Electric Meeting, 30.09.2006, Dresden, Germany

Publ.-Id: 10123 - Permalink

A short overview to radiopharmaceutical research at Saxony (Germany)
Steinbach, J.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Fa. Esteve (Laboratorios del Dr. Esteve, S.A.), 09.06.2006, Barcelona, Spain

Publ.-Id: 10122 - Permalink

Potential, limitations and application of organic PET- radiochemistry
Steinbach, J.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Fa. Esteve (Laboratorios del Dr. Esteve, S.A.), 09.06.2006, Barcelona, Spain

Publ.-Id: 10121 - Permalink

Wissenschaftliche und organisatorische Perspektiven des Instituts für Bioanorganische und Radiopharmazeutische Chemie beim Übergang zum Institut für Radiopharmazie
Steinbach, J.;
kein Abstract verfügbar
  • Lecture (others)
    Alumni-Treff des Instituts für Bioanorganische und Radiopharmazeutische Chemie, 02.-03.12.2005, Gohrisch, Germand

Publ.-Id: 10120 - Permalink

Entwicklung hochtemperaturstabiler Kontakte auf SiC
Weishart, H.; Heera, V.;
  • Lecture (others)
    3. NanoHoch-Projekttreffen in Dresden, 25.05.2007, Dresden, Germany

Publ.-Id: 10119 - Permalink

Magnetic patterning by means of ion irradiation and implantation
Fassbender, J.ORC; McCord, J.
A pure magnetic patterning by means of ion irradiation which relies on a local modification of the magnetic anisotropy of a magnetic multilayer structure has been first demonstrated in 1998. Since then also other magnetic properties like the interlayer exchange coupling, the exchange bias effect, the magnetic damping behavior and the saturation magnetization to name a few have also been demonstrated to be affected by ion irradiation or ion implantation. Consequently, all these effects can be used if combined with a masking technique or employing direct focused ion beam writing for a magnetic patterning and thus an imprinting of an artificial magnetic domain structure, which subsequently modifies the integral magnetization reversal behavior or the magnetization dynamics of the film investigated. The present review will summarize how ion irradiation and implantation can affect the magnetic properties by means of structural modifications. The main part will cover the present status with respect to the pure magnetic patterning of micro- and nanostructures.
Keywords: magnetism, patterning, ion irradiation, ion implantation

Publ.-Id: 10118 - Permalink

Properties of unflattened photon beams shaped by a multi leaf collimator
Pönisch, F.;
  • Poster
    AAPM Konferenz, 01.06.2006, Orlando, USA

Publ.-Id: 10116 - Permalink

Entwicklung eines Verfahrens zur Korrektur der Atembewegung in der Positronen-Emissions-Tomographie (PET)
Möckel, D.;
  • Lecture (others)
    Seminarvortrag Martin-Luther-Universität, 01.10.2004, Halle-Wittenberg, Dtl.

Publ.-Id: 10115 - Permalink

Design Criteria for an In-beam PET
Enghardt, W.;
  • Invited lecture (Conferences)
    Scientific Workshop for In-beam PET, 09.-10.05.2006, Dresden, Deutschland

Publ.-Id: 10114 - Permalink

Mikro-spill extraction
Crespo, P.;
  • Invited lecture (Conferences)
    Scientific Workshop for In-beam PET, 09.-10.05.2006, Dresden, Dtl.

Publ.-Id: 10113 - Permalink

Study of graded Ni-Ti Shape Memory Alloy film growth on Si(100) substrate
Martins, R. M. S.; Mücklich, A.; Reuther, H.; Beckers, M.; Schell, N.; Silva, R. J. C.; Pereira, L.; Braz Fernandes, F. M.;
In-situ x-ray diffraction (XRD) was employed to study the effect of the deliberate change of the ratio Ti/Ni during the deposition of Ni-Ti films. Thus, graded films were deposited exhibiting distinctive composition and crystalline structure along the growth direction. The as-sputtered films were ex-situ characterized by Auger Electron Spectroscopy (AES), Cross-sectional Transmission Electron Microscopy (XTEM), and Electrical Resistivity (ER) measurements (during thermal cycling). In this paper results are presented concerning a film with a Ti-rich composition in the central part and near-equiatomic composition in the extremities, following 4 distinct deposition periods (different Ti target powers). During the initial deposition step (near-equiatomic composition) the Ni-Ti B2 phase starts by stacking onto (h00) planes on the naturally oxidized Si(100) substrate due to the presence of the native Si oxide (2-3 nm). The increase of the power of the Ti target in the second and third steps induced the precipitation of Ti2Ni. When stopping the Ti co-sputtering, Ti2Ni “dissolves” and, thus, plays the role of a reservoir for the formation of B2 phase now preferentially stacking onto (110) with the system approaching again the equiatomic composition. The ex-situ study of the interface’s morphology has shown the presence of NiSi2 silicides (A-NiSi2 and B-NiSi2), Ti4Ni4Si7, Ti2Ni and a non-identified phase constituted by Ni, Ti and Si, most likely amorphous. During thermal cycling, electrical resistivity measurements revealed phase transitions associated with the B2, R-phase and B19’ phases. This type of studies allow the identification of intermediate states during deposition and annealing, and the correlation with the final structure of the film, being useful for the optimisation of the deposition parameters in order to fabricate films with a two-way reversible actuation.
Keywords: Ni-Ti thin films; Co-sputtering deposition; In-situ x-ray diffraction; Texture development; Interfacial diffusion
  • Applied Physics A 91(2008)2, 291-299

Publ.-Id: 10112 - Permalink

COVERS WP4 Benchmark 1 Fracture mechanical analysis of a thermal shock scenario for a VVER-440 RPV
Abendroth, M.; Altstadt, E.;
This paper describes the analytical work done by modelling and evaluating a thermal shock in a WWER-440 reactor pressure vessel due to an emergency case. An axial oriented semielliptical underclad/surface crack is assumed to be located in the core weld line. Threedimensional finite element models are used to compute the global transient temperature and stress-strain fields. By using a three-dimensional submodel, which includes the crack, the local crack stress-strain field is obtained. With a subsequent postprocessing using the j-integral technique the stress intensity factors KI along the crack front are obtained. The results for the underclad and surface crack are provided and compared, together with a critical discussion of the VERLIFE code.
Keywords: thermal shock, crack intensity factor, j-integral, fracture toughness, VVER-440
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-474 2007


Publ.-Id: 10111 - Permalink

Jahresbericht 2006 / Annual Report 2006
Forschungszentrum Dresden - Rossendorf, Vorstand;
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-469 2007


Publ.-Id: 10110 - Permalink

Annual Report 2006 - Institute of Ion Beam Physics and Materials Research
von Borany, J.; Heera, V.; Helm, M.; Möller, W.; (Editors)
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-466 2007


Publ.-Id: 10108 - Permalink

4-[18F]Fluorobenzaldehyde-O-(2-{2-[2-(pyrol-2,5-dion-1-yl)ethoxy] ethoxy}ethyl)oxim ([18F]FBOM): A novel prosthetic group for mild labelling of SH-group bearing biomacromolecules
Vogler, L.; Berndt, M.; Pietzsch, J.; Hultsch, C.; Wüst, F.;
The synthesis and application of 4-[18F]fluorobenzaldehyde-O-(2-{2-[2-(pyrol-2,5-dion-1-yl)ethoxy]ethoxy}ethyl)oxim ([18F]FBOM) as a novel prosthetic group for 18F labelling of SH-group bearing biomacromolecules is described.
The aminooxy-functionalised labelling precursor for the radiosynthesis of [18F]FBOM was synthesised in a four-step synthesis sequence with a total yield of 14%. [18F]FBOM could be obtained in a condensation reaction between the labelling precursor and [18F]fluorobenzaldehyde through formation of an oxim. The radiochemical yield ranged between 14 and 19% (decay-corrected). In a typical experiment, starting from 6.5 GBq of [18F]fluoride 730MBq of [18F]FBOM could be obtained within 80 minutes (including HPLC purification). The specific activity was determined to be 51 GBq/µmol. The lipophilicity of [18F]FBOM was determined to be logP = 0.84. The use of [18F]FBOM as SH-reactive group prosthetic group was demonstrated by the reaction with glutathion, low densitiy lipoproteins (LDL) and modified neurotensin derivatives. [18F]FBOM can easily be synthesised, and [18F]FBOM represents an interesting novel prosthetic group for the labelling of SH-group containing biomacromolecules with 18F under mild conditions.
  • Lecture (others)
    14. Arbeitsgruppentagung Radiochemie/Radiopharmazie, 04.-05.10.2006, Marburg, Germany

Publ.-Id: 10107 - Permalink

Formation and morphology control of nanostructures produced by PIII
Shevchenko, N.; Weber, J.; Reuther, H.; Kolitsch, A.;
Development of novel materials and structures for drug delivery systems is currently a very active field of research. Recently the drug-eluting stents were designed to deliver a drug locally from a surface layer to reduce restenosis. Noble gas ion implantation into metals can be used to form nanoscale cavities or sponge like structures. These nanostructures have unique characteristics which offer potential for medical applications such as metal-based drug-eluting stents.
Investigations of the influence of implantation parameters on the surface morphology and cavity characteristics (e.g. size, distribution, and degree of interconnection) have to date been rather limited.
In the present work we have studied the formation of nanostructures on stainless steel surfaces by plasma immersion ion implantation (PIII) using different gases (helium or argon), ion energies (between 5 – 35 keV) and ion fluences (> 1e18 at/cm2). The surface topography and structure of the modified materials have been analyzed by scanning electron microscopy and atomic force microscopy. The phase and element compositions have been examined by grazing incidence X-ray diffraction analysis (GIXRD), X-ray photoelectron spectroscopy, and elastic recoil detection analysis.
Varying the ion energy, fluences, and substrate temperature has been found to produce either void or sponge like structures on the nano- (~10 nm) to micro-scale (~1 µm). Apart from the austenite iron peaks, the GIXRD patterns of the implanted samples display weak peaks of ferrite (bcc iron) as well as oxide phases.
Keywords: Spongy structures, nanostructures, ion implantation, noble gas, stainless steel, drug-eluting stents
  • Poster
    PBII&D 07 - 9th International Workshop on Plasma Based Ion Implantation and Deposition, 02.-6.09.2007, Leipzig, Germany

Publ.-Id: 10106 - Permalink

Structural properties of thin HfSiO films
Teichert, S.; Muehle, U.; Fachmann, J.; Steinhoff, J.; Kudelka, S.; Wilde, L.; von Borany, J.; Eichhorn, F.;
Kein Abstract vorhanden.
  • Lecture (Conference)
    11th International Conference on the Formation of Semiconductor Interfaces (ICFSI), 19.-24.08.2007, Manaus-Amazonas, Brazil

Publ.-Id: 10105 - Permalink

Polymorphism in ferroic functional elements - Bridging length and time scales
Gemming, S.; Luschtinetz, R.; Chaplygin, I.; Seifert, G.; Loppacher, C.; Eng, L. M.; Kunze, T.; Olbrich, C.;
The present study describes an approach for the scale-bridging modeling of ferroic materials as functional elements in micro- and nanoelectronic devices. Ferroic materials are characterized by temperature-dependent complex ordering phenomena of the internal magnetic, electronic, and structural degrees of freedom with several involved length and time scales. Hence, the modelling of such compounds is not straightforward, but relies on a combination of electronic-structure-based methods like ab-initio and density-functional schemes with classical particle-based approaches given by Monte-Carlo simulations with Ising, lattice-gas, or Heisenberg Hamiltonians, which incorporate material-specific parameters both from theory and experiment. The interplay of those methods is demonstrated for device concepts based on electroceramic materials like ferroelectrics and multiferroics, whose functionality is closely related with their propensity towards structural and magnetic polymorphism.

In the present case, such scale-bridging techniques are employed to aid the development of an organic field effect transistor on a ferroelectric substrate generated by the self-assembly of field-sensitive molecules on the surfaces of ferroic oxides. Electronic-structure-based methods yield the microscopic properties of the oxide, the surface, the molecules, and the respective interactions. They are combined with classical particle-based methods on a scale-hopping basis. This combination allows to study the morphology evolution during the self-assembly of larger adsorbate arrays on the (defective) oxide surface and to investigate the interplay of low-temperature magnetic ordering phenomena with the ferroelectric functionality at higher temperatures in multiferroic oxides like the hexagonal manganites. The combination of density-functional data with classical continuum modelling also yielded a model Hamiltonian for the quick determination of the properties of a gate structure based on bio-functionalized carbon nanotubes.
Keywords: multiferroic, density-functional, tight-binding, Ising, Monte-Carlo, simulation, OFET

Publ.-Id: 10104 - Permalink

Neue Möglichkeiten der Modellierung und Beeinflussung der Strömungsverhältnisse in Gießprozessen
Eckert, S.; Boden, S.; Galindo, V.; Gerbeth, G.; Stefani, F.; Willers, B.;
Metallschmelzen in industriellen Prozessen unterliegen in der Regel verschiedenen Arten von Strömungen. Diese Strömungen haben einen entscheidenden Einfluss auf den Wärme- und Stofftransport, und damit zumeist auch auf die Effizienz des Prozesses oder die Qualität des Endproduktes. Zukünftige Anstrengungen im Hinblick auf eine Optimierung derartiger Anlagen oder Technologien müssen aus diesem Grund eine wirksame Strömungskontrolle berücksichtigen.
Elektromagnetische Felder eröffnen aufgrund des kontaktlosen Zugangs und der einfachen Regelbarkeit eine attraktive Möglichkeit zur Strömungskontrolle. Eine gezielte Einflussnahme setzt aber ein umfangreiches Wissen über das Strömungsfeld und die Wechselwirkung mit den elektromagnetischen Kraftfeldern voraus. Neben numerischen Simulationen sind Modellexperimente mit sogenannten „kalten“ Schmelzen, d.h. mit Flüssigmetallen mit einem Schmelzpunkt < 300°C, ein unverzichtbares Mittel, um die Strömungsvorgänge besser zu verstehen und geeignete Maßnahmen zur Strömungskontrolle zu ergreifen.
Im Vortrag werden an ausgewählten Beispielen mit Bezügen zu industriellen Anwendungen die Möglichkeiten einer elektromagnetischen Strömungskontrolle erläutert. In diesem Zusammenhang wird auf die wechselseitige Abhängigkeit von numerischen Berechnungen und Modellexperimenten mit „kalten“ Modellschmelzen hingewiesen. Es werden neue Entwicklungen auf dem Gebiet Messtechnik für Flüssigmetalle vorgestellt, die einen wirkungsvollen Einsatz der Modellexperimente erst ermöglichen.
Keywords: liquid metal flow, electromagnetic flow control, cold models, measuring techniques, casting, solidification
  • Invited lecture (Conferences)
    VDG-Seminar "Technologie des Feingießens - Innovation durch fundiertes Wissen", 23.-24.05.2007, Bad Dürkheim, Deutschland

Publ.-Id: 10103 - Permalink

Nanostructured metal surfaces by plasma immersion ion implantation
Shevchenko, N.; Weber, J.; Kolitsch, A.;
For bare metal stents the in-stent restenosis was a serious problem for about 25 - 35% of the patients and this spurred the medical device companies to come up with a solution. Drug-eluting stents are designed to deliver a drug locally from a polymeric coating to reduce tissue in growth and reduce restenosis to less then 8% of the treated patients. Development of novel materials and structures for drug delivery systems is still very actual topic.
In the present work plasma immersion ion implantation (PIII) using helium or argon plasmas has been employed for the nanostructures formation on metal surfaces with a view to their applications for metal-based drug-eluting stents. A multi-layer pore system on stent surfaces in the range from nanoscale to microscale sizes is desired for drug loading and controlling the rate of elution of therapeutic agents.
Recently we have investigate the formation of nanostructures on stainless steel surfaces by PIII at different gases (He, Ar), ion energies (between 5 – 35 keV) and ion fluences (> 1e18 at/cm2). The surface topography and structure of the implanted materials were analysed by scanning electron microscopy and atomic force microscopy. The phase and element compositions were examined by grazing incidence X-ray diffraction analysis, auger electron spectroscopy, and elastic recoil detection analysis.
Variety of nanostructures as well as their characteristics (e.g. size, distribution, degree of interconnection) can be controlled by varying the implantation parameters. The results of these studies have demonstrated that PIII is a promising technique for the surface topography modification of stainless steel for cardiovascular application.
Keywords: nanostructures, metal surfaces, ion implantation, PIII, stents, drug delivery systems
  • Poster
    EuroNanoForum 2007, 19.-21.06.2007, Düsseldorf, Germany

Publ.-Id: 10102 - Permalink

Tetrahydroquinoline and tetrahydroisoquinoline mixed ligand rhenium complexes with the SNS/S donor atom set
Zablotskaya, A.; Segal, I.; Lukevics, E.; Belyakov, S.; Spies, H.;
New oxorhenium complexes with 3-methylazapentane-1,5-dithiolate (SNMeS) and thiol functionalized monodentate tetrahydroquinolyl and tetrahydroisoquinolyl derivatives have been synthesized by simultaneous reaction of [PPh3]2[Re(O)Cl3] with tridentate HSNMeSH and the corresponding N-heterocycle containing thiol. The characterization of complexes involved elemental analysis, IR, 1H and 13C NMR spectroscopy and X-ray crystallographic analysis. The nature of the heterocycle in monodentate ligand, even situated at the distance of two methylene group length, has been found to have a significant influence on the molecular conformation. Metal complexes were found to be active in psychotropic in vivo and cytotoxicity in vitro screening.
Keywords: rhenium • mixed-ligand oxorhenium complexes • tetrahydroquinoline • tetrahydroisoquinoline • molecular structure • psychotropic activity • cytotoxicity • metal-based drugs

Publ.-Id: 10101 - Permalink

Synthese von 18F-markierten Biphenylen über Suzuki-Kupplung mit 4-[18F]Fluoriod-benzol
Steiniger, B.; Wüst, F.;
Als neuartige Markierungsmethode in der 18F-Chemie wurde die Suzuki-Kupplung von 4-[18F]Fluoriodbenzol mit verschiedenen Organoborverbindungen entwickelt. Anhand der Modellreaktion von p-Tolylboronsäure mit 4-[18F]Fluoriodbenzol wurde der Einfluss verschiedener Palladiumkomplexe, Basen und Lösungsmittel auf die Reaktion untersucht. Mittels der so optimierten Reaktionsbedingungen wurden verschiedene funktionelle Gruppen tragende 18F-markierte Biphenyle synthetisiert. Die Reaktion zeigte eine hohe Kompatibilität gegenüber vielen funktionellen Gruppen. Die radiochemischen Ausbeuten erreichten bis zu 95% (bezogen auf 4-[18F]Fluoriodbenzol) innerhalb von 5 Minuten.
  • Lecture (others)
    14. Arbeitsgruppentagung Radiochemie/Radiopharmazie, 04.-05.10.2006, Marburg, Germany

Publ.-Id: 10100 - Permalink

Effect of radiation on local control correlates with pre-treatment [18F]FDG uptake in FaDu tumours in nude mice
Schütze, C.; Bergmann, R.; Yaromina, A.; Hessel, F.; Kotzerke, J.; Steinbach, J.; Baumann, M.; Beuthien-Baumann, B.;
kein Abstract verfügbar
  • Poster
    10th International Wolfsberg Meeting 2007, 12.-14.05.2007, Ermatingen, Switzerland
  • Abstract in refereed journal
    Molecular Radiation Biology/Oncology 7(2007), 94

Publ.-Id: 10099 - Permalink

3-O-Methyl-6-18F-Fluoro-L-DOPA (OMFD) Uptake via L- Amino Acid Transporter in Tumor Cells and Inflammatory Cells
Haase, C.; Oswald, J.; Bergmann, R.; Füchtner, F.; Hoepping, A.; Pietzsch, J.;
System L amino acid transport is increased in various types of cancer. The new positron emission tomography (PET) tracer 3-O-methyl-6-18F-fluoro-L-DOPA (OMFD) is mainly accumulated via the system L and could serve to image cancer in vivo. However the differentiation between tumor and inflammatory reaction in tissues is often complicated. Therefore, we studied in vitro the accumulation mechanisms of OMFD in model systems of human tumors and inflammation, respectively. It is suggested that the high uptake of amino acid tracers is primarily caused by the higher transporter expression in tumors when compared to other tissues, e.g., inflammatory cells.
As previously shown, the subtype L-type amino acid transporter 1 (LAT1) is playing a key role of L amino acid transport in tumor cells. The functional LAT1 is a heterodimeric complex comprising a single membrane-spanning catalytic light chain protein (hLAT1) and the heavy chain of 4F2 antigen (h4F2hc), which are covalently linked via a disulfide bond.
For molecular characterization of L-type amino acid transporters focusing on the hLAT1-h4F2hc subtype quantitative RT-PCR was performed using the two different human tumor cell lines FaDu (squamous cell carcinoma) and HT-29 (colorectal adenocarcinoma). In comparison, phorbol ester stimulated THP-1 cells (a human monocyte/macrophage cell line) representing inflammatory cells were used. In vitro uptake assays were performed with HT-29, FaDu and THP-1 cells with OMFD under physiological amino acid concentrations.
OMFD demonstrated a saturable and sodium- and energy-independent accumulation in vitro in the different tumor cell lines, suggesting its uptake to be mediated mainly by sodium-independent LAT1. However, OMFD showed a significantly higher uptake in tumor cells when compared to inflammatory cells.
Our data demonstrate that OMFD could be a promising PET tracer for imaging of specific amino acid transport via LAT1 in tumors and, furthermore, for possible differentiation of tumorigenic from inflammatory processes. In conclusion, the identification and characterization of tumor specific amino acid transporters like LAT1 will be a helpful tool for diagnosis and therapy monitoring.
  • Poster
    Proteogenomics for Diagnosis, Imaging and Therapy of Cancer, 27.02.-01.03.2006, San Diego, California, USA

Publ.-Id: 10098 - Permalink

In vivo measurement of spin-spin relaxation time for localized PRESS magnetic resonance spectroscopy (MRS) of lipids
Strobel, K.; van den Hoff, J.; Pietzsch, J.;
Accumulation of excess abdominal visceral fat has been shown to play a crucial role in the development of cardiovascular disease and obesity-related disorders like diabetes mellitus, hyperlipidemia, and hypertension.
In the last years, rodent models have gained an important role in the investigation of adipose tissue (AT) biology and disorder. In this line, non-invasive differentiation and characterization of various AT deposits in the living animal is a current challenge. MRS at high magnetic field strength is a potential tool to learn more about the pathophysiological role of lipids in vivo.

The aim of the present study was to derive the spin-spin relaxation times T2 of 9 different proton resonances occurring in lipid spectra in vivo. With these values the correction factors M0/MTE (with the magnetization MTE = M0 x exp(-TE/T2), TE = echo time) for the peak integrals of the 9 different peaks can be calculated for specific TE. These correction factors can then be used to correct in vivo PRESS spectra to derive the true values for saturation and unsaturation of the triacylglycerols in lipids.

Localized MR spectra were generated in male Wistar rats with a 7 Tesla small animal scanner with a 30 cm bore (BioSpec 70/30, Bruker BioSpin MRI GmbH, Ettlingen, Germany) equipped with a mini imaging gradient coil system (gradient strength 400 mT/m) and a 1H transmit-receive quatrature coil with 72 mm inner diameter.

We used a localized PRESS sequence with a repetition time of 1.8 s and a series of different TE (TE = 12 – 50 ms) to calculate T2. We determined T2 for 9 different peaks (in the range from 0.9 – 5.35 ppm) by fitting the monoexponential model function MTE to the measured signal intensities at the different TE.

As results we got values for the spin-spin relaxation times T2 in the range from 24.7 ms to 57.4 ms. These values result in correction factors M0/MTE in the range from 2.25 to 1.42 for the 9 different peak integrals arising in lipid spectra derived with localized PRESS spectroscopy with TE = 20 ms.

We have measured 9 different T2-relaxation times of the protons of lipids in rats in vivo. These values have been used to correct localized PRESS spectra measured in vivo to obtain the true values for saturation and unsaturation of the fatty acids of AT deposits in experimental animal models. Prospectively, this method is also applicable in human studies using clinical MRS.
  • Poster
    EUROMAR 2007, 01.-06.07.2007, Tarragona, Spain

Publ.-Id: 10097 - Permalink

Expression of Neurotensin Receptors in Human Adeno- and Squamous Cell Carcinoma
Haase, C.; Bergmann, R.; Pietzsch, J.;
There is increasing interest in targeting peptide receptors and their ligands for tumor diagnostics and therapy since there is evidence that some of these receptors are overexpressed in tumors compared to normal tissues. Among these receptors playing a key role in tumor progression is the neurotensin receptor (NTR) family. The present study investigated both mRNA and protein expression of NTR in human adeno- (HT-29) and squamous (FaDu) cell carcinoma cell lines and in corresponding mouse xenograft models. mRNA analysis revealed a higher expression of NTR3 compared to NTR1 and NTR2. Protein analysis revealed enhanced signals for NTR1 followed by NTR2 both in tumor cells and xenografts. In contrast, no NTR3 protein expression was detected. Autoradiography with [3H]neurotensin showed higher receptor binding activity on HT-29 compared to FaDu.
  • Poster
    4th International Conference on Tumor Microenvironment: Progression, Therapy & Prevention, 06.-10.03.2007, Florence, Italy
  • Contribution to proceedings
    4th International Conference on Tumor Microenvironment: Progression, Therapy and Prevention, 06.-10.03.2007, Florence, Italy
    Current Contents

Publ.-Id: 10096 - Permalink

Einfluss verschiedener Y-86-DOTA-Chelate auf die Bioverteilung von Y-86-markierten DOTA L RNA Oligonukleotiden in Ratten
Schlesinger, J.;
Spiegelbildliche Oligonukleotide sind chemisch synthetisierte Desoxyribonukleinsäuren bzw. Ribonukleinsäuren, mit einer nicht natürlich vorkommenden L-Konfiguration der Ribose. Diese Modifizierung der Nukleinsäurestruktur führt zu einer besonders hohen Stabilität gegenüber dem enzymatischen Abbau in biologischen Medien (1). Zur Markierung von L Oligonukleotiden mit dem Positronen emittierenden Radiometall Y-86-Yttrium (t1/2 = 14,7 h) muss das Molekül mit einem Chelator funktionalisiert sein. Der Einfluss unterschiedlicher Y-86-Chelatstrukturen auf die pharmakologischen Eigenschaften von Y-86-Chelat-L Nukleinsäuren wurde am Beispiel eines L RNA 12mers 1 (Sequenz: 5’ Aminohexyl UGA CUG ACU GAC-3’, MW 3975) untersucht. Dazu wurde die L RNA 1 über zwei verschiedene Chelatoren mit 86Y(III) radiomarkiert und die Bioverteilung in Ratten untersucht.

Die Modifizierung des L RNA 12mers 1 mit DOTA erfolgte zum einen über einen reaktiven N Succinimidylester 2 – zu DOTA L RNA 3, zum anderen über ein Isothiocyanatderivat 4 zu DOTA bz L RNA 5. Die über eine Amidbindung 3 und eine Thioharnstoffbindung 5 DOTA-modifizierten L RNAs wurden anschließend mit Y-86 in radiochemischen Ausbeuten von 76 % bzw. 85 % radiomarkiert (2). Die Identität der Verbindungen 3a und 5a wurde mit geträgerten Y-86/Y-Markierungen und Massenspektrometrie nachgewiesen (3a m/z: 4447,0 [M+H]+; 5a m/z: 4611,3 [M+H]+). Die Bioverteilungsstudien wurden für jede Verbindung mit acht männlichen Wistar Ratten durchgeführt (3a: 240 ± 15 g Gewicht; 5a: 150 ± 7.5 g Gewicht).

Die Untersuchung der Bioverteilung der beiden Y-86-markierten L RNAs 3a und 5a zeigte für beide Substanzen eine hohe renale Ausscheidung, wobei aber eine unterschiedliche Retention der radiomarkierten Verbindungen in Nieren und Nebennieren beobachtet wurde. Der Standardized uptake value (SUV) ereichte für 3a in den Nieren einen Wert von 10 ± 2,0 nach 5 min und 6,1 ± 0,53 nach 60 min. Für die Verbindung 5a stieg der SUV in den Nieren von 13 ± 1,6 nach 5 min auf 14 ± 1,1 nach 60 min. Bemerkenswert hohe SUVs (3,5 ± 0,48 und 3,2 ± 0,33) wurden in den Nebennieren nach 60 min für beide Verbindungen beobachtet. Der SUV anderer Organe lag in dieser Untersuchung für 3a und 5a nach 60 min unter 1,0. Nach 12 h Inkubation in Rattenblut bei 37 °C konnte keine Zersetzung von 5a über HPLC-Analyse beobachtet werden.

Die unterschiedliche chemische Anbindung der Y-86-DOTA Chelate an die L-RNA 1 deutet neben den strukturellen Unterschieden der Y-86-Komplexe in 3a und 5a auf eine starke Beeinflussung der Bioverteilung des L Oligonukleotides hin. Die hohe metabolische Stabilität der L RNA verdeutlicht das Potential von L Oligonukleotiden als molekulare Sonden für die PET.

(1) Nat Biotechnol 14 (1996), 1112-5
(2) LDDD 3(5) (2006), 330-5
  • Poster
    45. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 25.-28.04.2007, Hannover, Deutschland
  • Abstract in refereed journal
    Nuklearmedizin 46(2007)2, A104

Publ.-Id: 10095 - Permalink

Combined 18Fluoro-L-DOPA-PET/CT as a tool for localization diagnostic in patients with congenital hyperinsulinism (CHI)
Blankenstein, O.; Mohnike, W.; Füchtner, F.; Mohnike, K.;
kein Abstract verfügbar
  • Lecture (Conference)
    ESPE / LWPES 7th Joint Meeting Paediatric Endocrinology, 21.-24.09.2005, Lyon, France

Publ.-Id: 10094 - Permalink

Effect of Moderate Hypercapnic Hypoxia on Cerebral Dopaminergic Activity and Brain O2 Uptake in Intrauterine Growth–Restricted Newborn Piglets
Bauer, R.; Walter, B.; Vorwieger, G.; Fritz, A.; Füchtner, F.; Zwiener, U.; Brust, P.;
There is evidence that intrauterine growth restriction (IUGR) is associated with altered dopaminergic function in the immature brain. Compelling evidence exists that in the newborn brain, specific structures are especially vulnerable to O2 deprivation. The dopaminergic system is shown to be sensitive to O2 deprivation in the immature brain. However, the respective enzyme activities have not been measured in the living neonatal brain after IUGR under hypercapnic hypoxia (H/H). Therefore, 18F-labeled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with positron emission tomography was used to estimate the aromatic amino acid decarboxylase activity of the brain of seven normal weight (body weight 2078 +/- 434g) and seven IUGR newborn piglets (body weight 893 +/- 109 g). Two positron emission tomography scans were performed in each piglet. All animals underwent a period of normoxia and moderate H/H. Simultaneously, cerebral blood flow was measured with colored microspheres and cerebral metabolic rate of O2 was determined. In newborn normal-weight piglets, the rate constant for FDOPA decarboxylation was markedly increased in mesostriatal regions during H/H, whereas brain oxidative metabolism remained unaltered. In contrast, moderate H/H induced in IUGR piglets a marked reduction of clearance rates for FDOPA metabolites (p < 0.05), which was accompanied by a tendency of lowering the rate constant for FDOPA conversion. Furthermore, IUGR piglets maintained cerebral O2 uptake in the early period of H/H, but during the late period of H/H, a significantly reduced cerebral metabolic rate of O2 occurred (p < 0.05). Thus, IUGR is accompanied by a missing activation of dopaminergic activity and attenuated brain oxidative metabolism during moderate H/H. This may indicate endogenous brain protection against O2 deprivation.

Publ.-Id: 10092 - Permalink

Small-Animal PET of Rat Lung Perfusion in Supine and Prone Position
Bergmann, R.; Richter, T.; Schlesinger, J.; Schiller, E.; Ragaller, M.; Strobel, K.; Pietzsch, J.;
Emerging experimental data indicate that the pulmonary blood flow remained directed toward the dorsal regions after turning animals from a supine to a prone position. This finding supported the hypothesis that the distribution of perfusion throughout the lung was not primarily dictated by the gravity but by the fractal behavior of the pulmonary vasculature. However there are only limited data about the spatial distribution of lung perfusion in rats in prone and supine position. The purpose of the study was to quantify the relative perfusion (Q) distribution in rat lungs in both positions using [68Ga]Ga-DOTA-microspheres with small-animal PET, -CT, and -MRI to obtain reference data for further investigations on injured rat lungs.

Regional pulmonary perfusion was investigated after injection of [68Ga]Ga-DOTA-microsphers (20 micrometer diameter) of albumin in both prone and supine positions in normal breathing rats, anesthetized with desflurane. The heart rate was continuously recorded. The right femoral artery and vein were cannulated, arterial blood pressure, blood gases, and pH were measured. The microspheres were intravenously applied. Emission data were collected for 30 min. Before and after the PET measurement the animals were studied with CT to investigate the lungs and to calculate their volumes. Randomly selected animals were studied also with smallanimal MRI. The [68Ga]-activity 3D distributions were analyzed from the coregistered volume data reconstructed with 3D OSEM MAP algorithm (resolution in the center of field of view 1.8 mm).

There were no significant differences of mean Q in the ventral and dorsal elements of normal rat lungs.

The body position (prone and supine) of normal breathing rats does not influence the mean Q btained with small-animal PET and the lung volumes measured with small-animal CT. The histogram of the regional blood flow in supine position reflects a more heterogeneous blood flow distribution.
Keywords: small-animal PET ; rat lung perfusion ; [68Ga]Ga-DOTA-microspheres ; supine and prone position
  • Poster
    Joint Molecular Imaging Conference 2007, 08.-11.09.2007, Providence, Rhode Island, USA

Publ.-Id: 10091 - Permalink

[18F]Fluoroacetate and [11C]Acetate Small-Animal PET Studies in Rats and Tumor Xenografts in Mice
Bergmann, R.; Richter, S.; Wüst, F.; Beuthien-Baumann, B.; Pietzsch, J.;
[18F]Fluoroacetate ([18F]FAC) is discussed as an addition to the well-established PET radiotracer [11C]acetate ([11C]ACE) for the diagnosis and treatment monitoring of low [18F]FDG accumulating cancer entities. The purpose of this study was to establish a reproducible method of [18F]FAC synthesis, and to assess the biodistribution and kinetics in rats and tumor bearing mice to evaluate the potential of [18F]FAC for tumor imaging, and to gain information about the [18F]FAC accumulation mechanism in human squamous cell carcinoma (FaDu) and adenocarcinoma (HT-29) xenografts.

Results and Discussion:
The optimized radiosynthesis of n.c.a. sodium [18F]FAC was performed in two steps: (1) Incorporation of fluorine into (methanesulfonyloxy)-acetic acid tert.-butyl ester as the superior labeling precursor in acetonitrile followed by (2) acidic hydrolysis of the resulting [18F]fluoroacetic acid tert.-butyl ester to afford [18F]FAC. Several consecutive purification gave sodium [18F]FAC in very reproducible radiochemical yields in high radiochemical purity (>95%) within 50 min. Arterial blood samples were analyzed and no metabolites of [18F]FAC were observed up to 60 min p.i. [18F]FAC was readily accumulated in FaDu and HT-29 tumors (tumor/muscle 1.8+/-0.2 mean+/-SEM, n=6) as shown in small-animal PET studies. [18F]FAC and [11C]ACE could clearly delineate the tumors and reached a tumor to muscle ratio up to two. Both agents showed a similar biodistribution. The differences were limited to the higher activity accumulation of the [11C]ACE in pancreas, spleen, kidneys, and the slower blood clearance of [18F]FAC. In some animals dehalogenation was observed.

The remotely-controlled two step/one pot synthesis of [18F]FAC represents a robust and reproducible procedure. The differences of biodistribution between [18F]FAC and [11C]ACE in rats and tumor bearing mice are relatively small. The absence of metabolites in the arterial blood plasma allows using the plasma activity for quantitative kinetic studies without further metabolite analyses.
(Partly supported by the EU project BioCare No. 505785)
Keywords: small-animal PET ; 18F-labeling ; [18F]fluoroacetate ; [11C]acetate ; tumor bearing mice
  • Poster
    Joint Molecular Imaging Conference 2007, 08.-11.09.2007, Providence, Rhode Island, USA

Publ.-Id: 10090 - Permalink

Entwicklungen im Bereich der Nutzung von Listmode am ECAT Exact HR+ des Forschungszentrum Rossendorf
Langner, J.; Pötzsch, C.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Seminar Forschungzentrum Jülich, 23.08.2006, Jülich, Germany

Publ.-Id: 10089 - Permalink

Multimodality Imaging of Tumor Xenografts in Mice with dedicated Small-Animal PET, Small-Animal CT, and Small-Animal MRI: Hardware and Software Solutions
Bergmann, R.; Hauser, J.; Strobel, K.; Pötzsch, C.; Hofheinz, F.; Pietzsch, J.; Beuthien-Baumann, B.;
Dedicated small-animal tomographs are nowadays available for the three major modalities PET, MRI, and CT. Utilization of all three techniques for true multimodality imaging requires the solution of several technical problems including reproducible animal positioning, overcoming file format incompatibilities and coregistration of the different image volumes, preferably without application of markers.
Methods: We developed an isolation chamber and adapter for imaging devices, enabling physiologic animal control, reproducible positioning, pathogen barrier, anesthesia, probe application and the use of catheter systems. Furthermore, we developed the necessary software for file format conversions and coregistration of the image volumes.
The basis is the animal holder system, consisting of the fixing adapters and the animal chamber that could be positioned in our three tomographs (microPET P4, SkyScan 1178, and BioScan 70/30 USR).
The animal holder system is temperature-controled. It allows gas anesthesia of the animals and could be used as a closed system. The bed is air heated.
In the different modalities the data are stored in different formats using different image matrix and pixel sizes. In order to analyze the data they are converted to a common data format (Siemens ECAT7) and the pixel sizes are adjusted. Residual differences in the relative positioning of the animals are corrected via coregistration. We implemented a mutual information algorithm using the conjugate gradient maximization method.
Validation studies showed a good coregistration of the images from PET, CT, and MRI. In longitudinal [18F]FDG studies the coregistration allowed to compare the tumor SUVmax data between different studies.
Conclusion: Multimodality imaging of small animal PET, -CT, and MRI allows the direct comparison and quantification of regional PET, CT, and MRI/MRS parameters enabling the characterization of functional and anatomical changes during tumor development and therapy.
The project was partly supported by the EU project BioCare No. 505785.
Keywords: small-animal PET, CT, MRI ; multimodality imaging ; animal chamber ; coregistration ; mutual information algorithm
  • Poster
    Joint Molecular Imaging Conference 2007, 08.-11.09.2007, Providence, Rhode Island, USA

Publ.-Id: 10088 - Permalink

Cyclam-based dendritic ligands bearing neuropeptides
Röhrich, A.;
kein Abstract verfügbar
  • Lecture (Conference)
    Supraphone meeting 2007, 31.05.-03.06.2007, Lipari, Italy

Publ.-Id: 10087 - Permalink

Neurotensin-Konjugate mit Cyclam-Kern – Synthese und Affinität zu NTR-1
Röhrich, A.; Stephan, H.; Kretzschmann, A.; Noll, S.; Bergmann, R.; Pietzsch, J.; Steinbach, J.;
Dendritische Liganden eröffnen einen neuen Zugang zu Radiometallpharmaka und zwar insbesondere dann, wenn es gelingt, radioaktive Metallnuklide im Kern topologisch so zu verkapseln, dass sie unter physiologischen Bedingungen kinetisch und thermodynamisch stabil fixiert sind. Eine Modifizierung der Dendrimeroberfläche erlaubt dann die Einstellung definierter Löslichkeits- und selektiver Bindungseigenschaften.
Wir berichten über die Synthese von sternförmigen Liganden mit peripheren Peptideinheiten sowie einem metallbindenden Zentrum. Als Peptid wird das biologisch aktive Neurotensinfragment NT-(8-13) eingeführt.[1] Dieses bindet an den Neurotensin-Rezeptor 1 (NTR-1), der insbesondere an duktalen exokrinen Pankreaskarzinomen stark überexprimiert ist.[2] Als Kernbaustein wird Cyclam (1,4,8,11-Tetraazacyclotetradecan) ausgewählt, das zur stabilen Bindung von diagnostisch und therapeutisch relevanten Radiometallnukliden, wie 64/67Cu, 99mTc und 186/188Re, geeignet ist. Derartige radioaktiv markierte Peptidkonjugate können Bedeutung in der Tumordiagnostik und Tumortherapie erlangen.
Es werden Ligand-Rezeptor-Bindungs-studien an NTR-1-überexprimierenden humanen Adenokarzinom(HT-29)-Zellen präsentiert. Erste Ergebnisse weisen auf eine sehr hohe Affinität des Tetramers I sowie des entsprechenden Kupfer(II)-Komplexes zum Neurotensin-Rezeptor 1 im pico-molaren Bereich hin und ist damit vergleichbar zu einem Tetramer anderer Struktur {3]. Es werden sich Untersuchungen zur Markierung mit 64Cu anschließen, um Aussagen zur metabolischen Stabilität dieses Liganden sowie zur Bioverteilung in vivo zu erhalten.

[1] B.M. Tyler-McMahon et al., Regul. Pept. 2000, 93, 125-136
[2] J. C. Reubi, Endocr. Rev. 2003, 24, 389-427.
[3] C. Hultsch et al., Bioorg. Med. Chem. 2006, 14, 5913-5920
  • Poster
    Wissenschaftsforum Chemie 2007, 16.-19.09.2007, Ulm, Deutschland

Publ.-Id: 10086 - Permalink

In vivo Stoffwechseluntersuchungen mit Hilfe der Positronen-Emissions-Tomographie (PET)
Wüst, F.; Pietzsch, J.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Forschungsinstitut für die Biologie landwirtschaftlicher Nutztiere, 16.01.2006, Dummerstorf, Deutschland

Publ.-Id: 10084 - Permalink

Carbon-11 labelling chemistry
Wüst, F.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Postitron emission tomography (PET): Technology and application, 05.-07.04.2006, London, Great Britain

Publ.-Id: 10083 - Permalink

18F-Markierungen mit kleinen Markierungsbausteinen
Wüst, F.;
  • Invited lecture (Conferences)
    Institutskolloquium, 03.08.2006, München, Germany

Publ.-Id: 10082 - Permalink

Synthesis of 18F-labeled stilbenes from 4-[18F]fluorobenzaldehyde
Wüst, F.; Gester, S.; Pietzsch, J.;
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Positron emission tomography (PET): Technology and application, 28.-30.03.2007, London, Great Britain

Publ.-Id: 10081 - Permalink

Übergangsmetallvermittelte Reaktionen mit den kurzlebigen Positronen-strahlern 11C und 18F: Neue radiochemische Methoden zur C-C und C-N Bindungsknüpfung
Wüst, F.;
kein Abstract verfügbat
  • Lecture (others)
    Jungchemikerforum TU Dresden, 15.11.2004, Dresden, Germany

Publ.-Id: 10080 - Permalink

Characterization of PET radiotracer uptake in human leukemia cell line THP-1, a model for the study of monocyte-macrophage differentiation
Pietzsch, J.; Haase, C.;
kein Abstract verfügbar
  • Poster
    8th World Congress on Inflammation, 16.-21.06.2007, Copenhagen, Denmark
  • Abstract in refereed journal
    Inflammation Research (2007)Suppl. 3, S459

Publ.-Id: 10079 - Permalink

Imaging of metabolic pathways of modified lipoproteins in vivo using small animal positron emission tomography (PET)
Pietzsch, J.; Hoppmann, S.; Haase, C.; Wüst, F.; van den Hoff, J.;
kein Abstract verfügbar
  • Lecture (Conference)
    8th World Congress on Inflammation, 16.-21.06.2007, Copenhagen, Denmark
  • Abstract in refereed journal
    Inflammation Research (2007)Suppl. 3, S394

Publ.-Id: 10078 - Permalink

Lateral variation of target poisoning during reactive magnetron sputtering
Güttler, D.; Grötzschel, R.; Möller, W.;
The reactive gas incorporation into a Ti sputter target has been investigated using laterally resolving ion beam analysis during DC magnetron deposition of TiN in an Ar/N2 atmosphere. At sufficiently low reactive gas flow, the nitrogen incorporation exhibits a pronounced lateral variation, with a lower areal density in the target race track compared to the target centre and edge. The findings are reproduced by model calculations. In the race track, the balance of reactive gas injection and sputter erosion is shifted towards erosion. The injection of nitrogen is dominated by combined molecular adsorption and recoil implantation versus direct ion implantation.
Keywords: Thin Film Deposition, Magnetron Sputtering, Target Poisoning, Modelling
  • Applied Physics Letters 90(2007), 263502

Publ.-Id: 10077 - Permalink

Nanostructures by Ion-Driven Self-Organisation
Möller, W.;
No abstract available
  • Lecture (others)
    Seminar, 20.03.07, Aarhus, Denmark

Publ.-Id: 10076 - Permalink

Nanostructures by Ion-Driven Self-Organisation
Möller, W.;
No abstract available
  • Lecture (others)
    Seminar, 02.02.2007, Caen, France

Publ.-Id: 10075 - Permalink

Oberflächen- und Schichtanalyse mit Hochenergie-Ionen
Möller, W.;
No abstract available
  • Lecture (others)
    Weiterbildungskurs "Surface Engineering und Nanotechnologie (SENT), Charakterisierung dünner Schichten", 08.12.2004, Dresden, Deutschland

Publ.-Id: 10073 - Permalink

Möller, W.;
No abstract available
  • Lecture (others)
    Weiterbildungskurs "Surface Engineering und Nanotechnologie (SENT), Herstellung und Anwendung dünner Schutzschichten", 27.10.2004, Dresden, Deutschland

Publ.-Id: 10072 - Permalink

Möller, W.;
No abstract available
  • Lecture (others)
    Weiterbildungskurs "Surface Engineering und Nanotechnologie (SENT), Herstellung und Anwendung dünner Schutzschichten", 27.10.2004, Dresden, Deutschland

Publ.-Id: 10071 - Permalink

Plasma Surface Interaction and Ion Bombardment
Möller, W.;
No abstract available
  • Invited lecture (Conferences)
    Tutorial "Fundamentals and Trends in Plasma Processing", Int. Konf. "Plasma Surface Engineering", 11.09.2004, Garmisch-Partenkirchen, Deutschland

Publ.-Id: 10070 - Permalink

Fundamentals of Ion Beam Analysis
Möller, W.;
No abstract available
  • Lecture (Conference)
    Tutorial "Thin Film Diagnostics", EU-RTN "New Fullerene Like Materials", 04.06.2004, Dresden, Deutschland

Publ.-Id: 10069 - Permalink

Experimental hypoxia is a potent stimulus for radiotracer uptake in vitro: Comparison of different tumor cells and primary endothelial cells
Oswald, J.; Treite, F.; Haase, C.; Kampfrath, T.; Mäding, P.; Schwenzer, B.; Bergmann, R.; Pietzsch, J.;
Hypoxia causes upregulation of vascular endothelial growth factor (VEGF) which is a key regulator in tumor angiogenesis and essential for the proliferation of endothelial cells. Endothelial cells have been described to accumulate radiotracers like 18F-FDG. However, the contribution of radiotracer uptake by endothelial cells to uptake measured in tumors by positron emission tomography (PET) is still unclear. In this study 18F-FDG and 18F-FMISO radiotracer uptake in various tumor and primary endothelial cells cultured at hypoxic conditions was investigated. Experimental hypoxia was confirmed by significant upregulation of VEGF mRNA. In comparison to normoxic conditions, cellular uptake of 18F-FDG was significantly increased at hypoxic conditions in two of the tumor and all endothelial cells, whereas 18F-FMISO uptake was only enhanced in tumor cell lines HT-29 and MCF-7. Our data showed a marked influence of experimental hypoxia on the metabolism and gene expression of tumor and endothelial cells in vitro. This indicates an important contribution of endothelial cells to 18F-FDG radiotracer uptake in tumors and for the visualization of tumors by means of PET.
Keywords: Hypoxia; VEGF; Endothelial cells; Radiotracer uptake; 18F-FDG; 18F-FMISO

Publ.-Id: 10068 - Permalink

Receptor for Advanced Glycation Endproducts in Health and Disease
Pietzsch, J.; (Editor)
kein Abstract verfügbar
  • Book (Editorship)
    Trivandrum, Kerala, India: Research Signpost, 2007
    50 Seiten

Publ.-Id: 10067 - Permalink

An algebraic approach to bare nucleon matrix elements
Zschocke, S.;
  • Lecture (others)
    Institut für Theoretische Physik, 10.12.2004, Dresden, Deutschland

Publ.-Id: 10066 - Permalink

Splitting and mixing of the ρ and ω in nuclear matter
Zschocke, S.;
  • Lecture (Conference)
    KFKI-RMKI, 19.11.2004, Budapest, Hungary
  • Invited lecture (Conferences)
    FIAS, 03.12.2004, Frankfurt am Main, Deutschland

Publ.-Id: 10065 - Permalink

Mass-shift of the ρ and ω meson and their mixing in nuclear matter
Zschocke, S.;
Mass-shift of the ρ and ω meson and their mixing in nuclear matter
  • Lecture (others)
    Institut für Theoretische Physik, 06.06.2004, Dresden, Deutschland

Publ.-Id: 10064 - Permalink

ρ − ω splitting and mixing in nuclear matter
Zschocke, S.;
  • Lecture (Conference)
    DPG Frühjahrstagung, 08.-12.03.2004, Köln, Deutschland

Publ.-Id: 10063 - Permalink

Radical Enhanced Atomic Layer Deposition of Tantalum Oxide
Niskanen, A.; Kreissig, U.; Leskelä, M.; Ritala, M.;
Tantalum oxide was deposited by radical enhanced atomic layer deposition using tantalum ethoxide and oxygen radicals. The radicals were produced by dissociating oxygen gas in a remote microwave plasma discharge. Argon was used as the carrier and purge gas. The films were deposited at 150 and 250°C on glass, silicon, and platinum substrates. Growth rate of the films was 0.19 nm per cycle with a 0.6 s pulse length for tantalum ethoxide and 3 s for oxygen radicals. The films were amorphous according to X-ray diffraction. The densities measured by X-ray reflectivity were between 7.1 and 7.6 g/cm3 for films grown both at 150 and 250°C. The dielectric constants were 28 and 36 for films grown on platinum electrodes at 150 and 250 °C, respectively. The leakage current densities at 1 MV/cm electric field were less than 1 x 10-8 A/cm2 for both deposition temperatures. The effect of water as an additional oxidant was studied at 250 °C. The water was supplied as a separate pulse either right before or after the tantalum ethoxide pulse.
  • Chemistry of Materials 19(2007), 2316-2320

Publ.-Id: 10062 - Permalink

Photon scattering from 92Mo, 98Mo and 100Mo up to the neutron-seperation energy
Rusev, G.;
  • Lecture (Conference)
    DPG Frühjahrstagung, 08.-12.03.2004, Köln, Deutschland

Publ.-Id: 10061 - Permalink

The ELBE Microbeam
Pawelke, J.;
  • Lecture (Conference)
    Microbeam-Workshop, 30.-31.03.2004, Darmstadt, Deutschland

Publ.-Id: 10060 - Permalink

Feasibilty of dose quantification with in-beam PET data in radiotherapy with 12C and proton beams
Parodi, K.;
  • Invited lecture (Conferences)
    BROWN BAG - physics seminar, 12.12.2004, Boston, USA

Publ.-Id: 10059 - Permalink

The feasibility of in-beam PET for proton therapy
Parodi, K.;
  • Invited lecture (Conferences)
    BROWN BAG - physics seminar, 02.02.2004, Boston, USA

Publ.-Id: 10058 - Permalink

Testing of X-ray sensitive detectors at ELBE
Naumann, L.;
  • Lecture (Conference)
    CBM Collaboration Meeting, 07.10.2004, Darmstadt, Deutschland

Publ.-Id: 10057 - Permalink

FAIR an international accelerator facility for antiproton and ion beam research in Darmstadt
Naumann, L.;
  • Invited lecture (Conferences)
    INTAS TRD Collaboration Meeting, 01.07.2004, Gatchina, Russia

Publ.-Id: 10056 - Permalink

Structural and tribological properties of cluster-assembled CNx films
Blomqvist, M.; Bongiorno, G.; Podesta, A.; Serin, V.; Abrasonis, G.; Kreissig, U.; Möller, W.; Coronel, E.; Wachtmeister, S.; Csillag, S.; Cassina, V.; Piseri, P.; Milani, P.;
We report the structural and tribological characterization of nanostructured CNx thin films produced by the deposition of a supersonic carbon cluster beam assisted by nitrogen ion bombardment. The influence of the deposition parameters on the chemical composition and structure of the films has been systematically studied by X-ray photoelectron spectroscopy, elastic recoil detection analysis, transmission electron microscopy and atomic force microscopy. Depending on the deposition parameters, the films show a structure ranging from amorphous to disordered graphitic with interlinked planes. Nitrogen content depends on the nitrogen ion kinetic energy. The films have a very low density with a high surface roughness. Friction measurements at the nanoscale show a correlation between nitrogen content and mechanical properties of the system.
  • Applied Physics A 87(2007), 767-772

Publ.-Id: 10055 - Permalink

Bi-annual Report 2005/06 - Rossendorf Beamline at ESRF (ROBL-CRG)
Scheinost, A.; von Borany, J.; (Editors)
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Dresden-Rossendorf; FZD-463 2007


Publ.-Id: 10054 - Permalink

Dileptons and charm as probes of chiral restoration
Kämpfer, B.;
  • Invited lecture (Conferences)
    Int. Conf. High Energy Phys., 16.-22.04.2004, Bejing, China

Publ.-Id: 10053 - Permalink

Quasiparticle model of QCD matter above and below Tc and at large μ
Kämpfer, B.;
  • Lecture (Conference)
    Int. Symp. ”The QCD phase diagramme: from theory to experiment”, 28.05.-03.06.2004, Skopelos, Greece

Publ.-Id: 10052 - Permalink

Phantastische Ausblicke auf unser Universum
Kämpfer, B.;
  • Lecture (others)
    Urania-Seniorenakademie, 05.05.2004, Dresden, Deutschland

Publ.-Id: 10051 - Permalink

QCD equation of state above and below Tc
Kämpfer, B.;
  • Lecture (Conference)
    XLII Int. Winter Meeting on Nucl. Physics, 25.-31.01.2004, Bormio, Italy

Publ.-Id: 10050 - Permalink

Baryon resonances and the production of light vector mesons near thresholds
Kämpfer, B.;
  • Lecture (Conference)
    Internat. Workshop, 11.-17.01.2004, Hirschegg, Österreich

Publ.-Id: 10049 - Permalink

Overview of the present status of the SRF gun design and construction
Michel, P.;
  • Invited lecture (Conferences)
    Workshop on Advanced Free Electron Lasers and Their Applications, 24.-25.06.2004, Taiwan, China

Publ.-Id: 10048 - Permalink

Electron Beam Diagnostics at the ELBE Free Electron Laser
Michel, P.;
  • Invited lecture (Conferences)
    Workshop on Advanced Free Electron Lasers and Their Applications, 24.-25.06.2004, Taiwan, China

Publ.-Id: 10047 - Permalink

Design and Status of the Radiation Source ELBE and its FEL(s)
Michel, P.;
  • Invited lecture (Conferences)
    Workshop on Advanced Free Electron Lasers and Their Applications, 24.-25.06.2004, Taiwan, China

Publ.-Id: 10046 - Permalink

Experiments and simulation on bubbly flow in a complex 3D flow field
Lucas, D.; Prasser, H.-M.; Krepper, E.; Beyer, M.;
A new approach for the modelling of poly-dispersed bubbly flows – the so-called Inhomogeneous Multi Bubble Size Group (MUSIG) model was developed jointly by FZD and ANSYS. It was implemented into the CFX code and is now available starting with code version 10. This model enables the consideration of a number bubble classes in the mass balance as well as in the momentum balance. Usually only few classes are required for the momentum balance to reflect the bubble size dependent de-mixing of small and large bubbles caused by the inversion of the sign of the lift force with increasing bubble diameter. The model was developed and first tested using data for vertical pipe flow. To show the indepen¬dency of the model on geometry and to test it for more complex flow situations, now experiments were conducted with a pronounced three-dimensional character of the flow fields. A diaphragm which blocks about one half of the pipe was placed into the vertical DN200 test sections available at the TOPFLOW facility of FZD. Main feature is the trans¬location of the diaphragm to scan the 3D void field with a stationary wire-mesh sensor. Be¬sides the measurement of time-averaged void fraction fields, a novel data evaluation method was developed to extract estimated liquid velocity profiles from the wire-mesh sensor data. Simulations were done using CFX-10 and applying the Inhomogeneous MUSIG model. In general the complex flow including a recirculation zone behind the obstacle (where bubble coalescence is observed) and a pronounced jet of high liquid velocity at the unobstructed side (were bubble break-up dominates) are reflected well in the simulations. There is a strong interaction between size dependent bubble migration in the complex liquid velocity field (mainly caused by the lift force) and local bubble coalescence and break-up. The data clearly demonstrate the necessity to consider the bubble size dependent bubble migration for an adequate simulation of bubbly flows in complex geometries. Some weaknesses of the simulations are connected with shortcomings in the modelling of bubble coalescence and break-up.
Keywords: bubbly flow, 3D, flow field, CFD
  • Lecture (Conference)
    45th European Two-Phase Flow Group Meeting, 22.-25.05.2007, Toulouse, France

Publ.-Id: 10045 - Permalink

Stability effect of the lateral lift force in bubbly flows
Lucas, D.; Krepper, E.; Prasser, H.-M.; Manera, A.;
The role of the lift force for the stability of bubbly flows is discussed. The main interest is directed towards bubble columns, since instabilities caused by the lift force may be one important reason for the transition from homogeneous to heterogeneous flow regimes. The lift force acts on rising bubbles in lateral direction, when gradients of the liquid velocity are present. Such gradients may result from the main liquid flow or from local disturbances in case of initially homogeneous flows. Depending on the sign of the lift force such local disturbances in a homogeneous flow may be damped or enhanced. The corresponding feedback mechanism was previously analysed by means of a linear stability analyses. In the result criteria for stability were obtained for mono-dispersed flow, for a flow with two bubble size groups and finally with some additional approximations also for the case of N bubble size groups or a given bubble size distribution. Recently two different groups confirmed the stability criteria experimentally. Now the effects were investigated also by means of CFD simulations. In a first step bubble coalescence was excluded, while the second step comprises a numerical study which includes coalescence. In the latter case coalescence leads to a transition from stable to instable flow patterns along the height position in the column. The transitions fit well together with the criteria for stability. Finally the influence of the lift force is discussed also for other flow situations.
Keywords: bubbly flow, stability, bubble column, lift force
  • Contribution to proceedings
    International Conference on Multiphase Flow - ICMF 2007, 09.-13.07.2007, Leipzig, Germany
    paper S1_Mon_C_9
  • Lecture (Conference)
    International Conference on Multiphase Flow - ICMF 2007, 09.-13.07.2007, Leipzig, Germany

Publ.-Id: 10044 - Permalink

Spontaneous symmetry breaking and rotational bands
Frauendorf, S.;
  • Invited lecture (Conferences)
    Fall meeting of the Div. of Nucl. Phys. of the American Physical Society, 02.10.2004, Chicago, USA

Publ.-Id: 10043 - Permalink

Normal persistent currents and gross shell structure at high spin
Frauendorf, S.;
  • Lecture (Conference)
    Workshop on mesoscopic physics, 01.10.2004, Michigan, USA

Publ.-Id: 10042 - Permalink

Probing shape coexistence by dipole excitations
Frauendorf, S.;
  • Lecture (others)
    Forschungszentrum Rossendorf, 01.07.2004, Dresden, Deutschland

Publ.-Id: 10041 - Permalink

Experimental evidence for chirality
Frauendorf, S.;
  • Lecture (others)
    Niels Bohr Institute, University of Copenhagen, 02.06.2004, Copenhagen, Danmark

Publ.-Id: 10040 - Permalink

Symmetries of the cranked mean field
Frauendorf, S.;
  • Invited lecture (Conferences)
    International Nuclear Physics Conference, 07.06.2004, Goeteborg, Sweden
  • Invited lecture (Conferences)
    Niels Bohr Institute, 01.06.2004, Copenhagen, Danmark

Publ.-Id: 10039 - Permalink

Tilted rotation
Frauendorf, S.;
  • Lecture (others)
    Bejing University, 03.04.2004, Bejing, China

Publ.-Id: 10038 - Permalink

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