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  • Artikel: DFG Deutsche Nationallizenzen  (11)
  • Digitale Medien  (11)
  • 1995-1999  (7)
  • 1985-1989  (3)
  • 1965-1969  (1)
Datenquelle
  • Artikel: DFG Deutsche Nationallizenzen  (11)
Materialart
  • Digitale Medien  (11)
Erscheinungszeitraum
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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 2517-2522 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We report measurements of proton-exchanged LiNbO3 using acoustic microscopy in the V(z) mode, together with optical waveguide mode observations. In the present case, samples were prepared using dilute benzoic acid containing a small mole percent of lithium benzoate. Substantial changes in surface acoustic wave (SAW) propagation velocity due to proton exchange have been observed on all three major-axis crystal cuts, with both increase and decrease in velocity occurring, depending on propagation direction. Changes in attenuation are also observed. Using the V(z) technique with a line-focus cylindrical lens has enabled complete velocity surfaces for proton-exchanged lithium niobate to be obtained with reasonable precision, based on simplified isotropic calculations of acoustic propagation in layered media and the assumption that the proton-exchange region is uniform with a depth obtainable from optical waveguide mode calculations. It is concluded that the V(z) acoustic microscopy technique can provide a powerful tool in the study of the SAW properties of proton-exchanged LiNbO3.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 9189-9193 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 539 (1988), S. 0 
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
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  • 4
    ISSN: 1399-0047
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: We have synthesized a series of non-macrocyclic ligands to FKBP12 that are comparable in binding potency and peptidyl prolyl isomerase (PPIase) inhibition to FK506 itself. We have also solved the structure of one of these ligands in complex with FKBP12, and have compared that structure to the FK506–FKBP12 complex. Consistent with the observed inhibitory equipotency of these compounds, we observe a strong similarity in the conformation of the two ligands in the region of the protein that mediates PPIase activity. Our compounds, however, are not immunosuppressive. In the FKBP12–FK506 complex, a significant portion of the FK506 ligand, its `effector domain', projects beyond the envelope of the binding protein in a manner that is suggestive of a potential interaction with a second protein, the calcium-dependent phosphatase, calcineurin, whose inhibition by the FKBP 12–FK506 complex interrupts the T-cell activation events leading to immunosuppression. In contrast, our compounds bind within the surface envelope of FKBP12, and induce significant changes in the structure of the FKBP12 protein which may also affect calcineurin binding indirectly.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Microchimica acta 57 (1969), S. 480-489 
    ISSN: 1436-5073
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Flüssigkeits-Szintillationszählung zur Bestimmung von14C-markiertem Ametryn in Dünnschichtchromatogrammen wurde eingehend geprüft. Alterung, Löschungseffekt von Trägersubstanz und Adsorptionsmitteln, Temperaturbeständigkeit der Verbindung in adsorbiertem Zustand wurden untersucht. Die Reproduzierbarkeit beträgt 1 bis 2%, die Nachweisgrenze 0,005μg pro Tüpfel, das Signal-Hintergrund-Verhältnis 3∶1. Zur Lokalisierung der Flecken wurde die Fluoreszenzlöschung herangezogen. Die Ausbeute nach 30 Minuten Entwicklung auf Silikagelplatten war ungefähr 90% Ametryn, unabhängig vom Laufmittel. Bei zweidimensionaler Arbeitsweise wurden 75% wiedergefunden. Die Ausbeute aus Wasser- und Bodenproben lag zwischen 78 und 88%.
    Notizen: Summary The use of the liquid scintillation counting method for the determination of14C labelled ametryne on thin-layer chromatograms has been thoroughly investigated. Aging, quenching effect of carrier and adsorbents as well as temperature stability of the compound in the adsorbed state have been studied. The method has a reproducibility of 1 to 2% and a detection limit of 0.005μg per spot at a 3 ∶ 1 signal to background ratio. Fluorescence quenching was used for the location of spots on the chromatogram. Recovery studies were carried out by this method. After 30 minutes development on a chromatoplate coated with silicagel, about 90% of the ametryne was recovered independent of solvent system used. About 75% of the ametryne was recovered from a two-dimensional chromatogram. Recoveries of ametryne from water and soil samples ranged between 78 and 88%.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-1939
    Schlagwort(e): Ascoglossans ; Caphyra rotundifrons ; Chemical defense ; Chlorodesmis ; Plant-herbivore-predator interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Because feeding specialization among marine herbivores is rare, marine communities provide a simplified system for identifying factors selecting for specialization. On Australia's Great Barrier Reef, we investigated interactions among the chemically-defended seaweed Chlorodesmis fastigiata, herbivores specialized on this alga, and potential predators of these herbivores. Chlorodesmis is a low preference food for reef fishes but appears to be the only food of the crab Caphyra rotundifrons and the ascoglossan gastropods Elysia sp. and Cyerce nigricans. The crab is found only in patches of Chlorodesmis, feeds solely on the alga, and selectively shelters in it in laboratory choice experiments. Crab grazing on the red seaweed Acanthophora spicifera was stimulated when this alga was coated with increasing concentrations of the cytotoxic diterpenoid chlorodesmin, the major secondary metabolite of Chlorodesmis. Crabs did not sequester Chlorodesmis metabolites but avoided predators by sheltering in the unpalatable alga. All crabs tethered on the reef without access to Chlorodesmis patches were rapidly eaten; those with access to Chlorodesmis patches were much less susceptible to predation. The cryptic ascoglossan Elysia sp. was found exclusively in patches of Chlorodesmis and sequestered metabolites from the alga. Living Elysia were unpalatable to the common wrasse Thalassoma lunare in laboratory assays, but the crude organic extract of Elysia did not significantly deter feeding by Thalassoma. Elysia sequestered chlorodesmin, which deterred feeding by reef fishes in field assays but was ineffective against Thalassoma in laboratory assays at 5% food dry mass. Unlike Elysia, the aposematically colored ascoglossan Cyerce nigricans sequestered Chlorodesmis metabolites in relatively small amounts, but produced larger amounts of unrelated polypropionate compounds. Cyerce were never attacked by fishes and the crude organic extract of this slug strongly deterred feeding by wrasses in laboratory assays. The dorid nudibranch Gymnodoris sp. was found only in Chlorodesmis patches and appeared to be a specialized predator on Elysia; it would not prey on Cyerce. Data from this and other recent investigations demonstrate that some small marine herbivores feed selectively or exclusively on seaweeds that are chemically defended from fishes. This association reduces predation on the herbivores and suggests that escape from and deterrence of predation may be a dominant factor selecting for specialization among these herbivores.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 42 (1997), S. 404-407 
    ISSN: 1573-2568
    Schlagwort(e): IRRITABLE BOWEL SYNDROME ; UROLOGICAL SYMPTOMS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Irritable bowel syndrome patients often complainof urinary symptoms such as frequency, urgency, anddysuria, raising the possibility of inappropriatereferral to the urologist. To resolve this issue, the prevalence of irritable bowel syndrome wascompared in patients attending urological and controlclinics (dermatology and ENT). The overall prevalence ofirritable bowel syndrome was 31.2% in the urological clinic compared with 21.2% in the controls (P〈 0.001), but striking differences emerged, dependingon presenting complaint. Irritable bowel symptoms wereparticularly common in patients presenting with loin pain (male: 40.9%, P = 0.004; female: 50%, P =0.03), dysuria (male: 43.8%, P = 0.007; female: 46.2%,P = 0.01) and frequency/urgency (male: 31.7%, P = 0.002;female: 42.4%, P = 0.006), and the male/femaleprevalence was 24% and 44%. These results suggest that inirritable bowel syndrome, urinary symptoms includingloin pain can present diagnostic dilemmas in both thegastroenterological and urological setting, underlining the importance of specialists in these fieldsworking together in order to define better ways ofmanaging such patients.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of radioanalytical and nuclear chemistry 211 (1996), S. 173-179 
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract The phase behaviour of carbon dioxide confined in VYCOR glass at pressures below that of the bulk triple point (∼0.51 MPa) has been investigated. The temperature at which freezing occurs appears to be pressure dependent below 0.3 MPa. As experiments are performed at successively lower pressures, the confined phase transitions gradually disappear, due to either partial pore filling, or the proximity of the confined triple point.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of radioanalytical and nuclear chemistry 211 (1996), S. 165-171 
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract In confined (nanometer-scale) geometry, the effects of substrate forces and finite size produce a shift of the gas ⇔ liquid phase boundary from that found in corresponding bulk. The pore transitions also show marked hysteresis. The phase behaviour of a binary gas mixture in confined geometry is likely to depend on the miscibility of the system and the interaction between the substrate and the individual fluid molecules/atoms. Here, we present the results of a pilot positronium annihilation study of the condensation and evaporation of argon-nitrogen mixtures confined in ∼4 nm diameter cylindrical pores in VYCOR glass.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of radioanalytical and nuclear chemistry 210 (1996), S. 255-271 
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract In this paper we present a brief review of the current state of positron annihilation research into the phase behaviour of fluids confined within restricted boundaries. We summarise, in the form of selected examples, the work done so far on: (1) fluids confined in the nanometer-size pores of VYCOR glass, with particular emphasis on the confined phase diagram and the mechanisms behind phase transitions compared to bulk. (2) The adsorption/physisorption of gases on internal surfaces of grafoil and the potential of positron technique for revealing physical properties, such as the intricate molecular arrangements during phase transitions of the “layered” fluid.
    Materialart: Digitale Medien
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