Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1995-1999  (7)
  • 1985-1989  (3)
  • 1960-1964  (4)
Materialart
Erscheinungszeitraum
Jahr
  • 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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 202 (1964), S. 1316-1318 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] MITOCHONDRIA catalyse a rapid incorporation of phosphorus-32 from 32Pi or AT32P into a protein-bound phosphohistidine. This phosphohistidine appears to be an intermediate in the formation of ATP from inorganic phosphorus, and has been suggested as a key intermediate in oxidative phosphorylation1-3. ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Experimental mechanics 1 (1961), S. 134-141 
    ISSN: 1741-2765
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract One method of determining the strains on the surface of a metal part is by the use of a birefringent coating. Because of the thickness of the coating, however, the observed fringe order depends not only on the surface strains but also on two other factors, namely, the curvature that the surface undergoes and the variation of strain acrose the thickness of the coating. These thickness effects have already been studied in a paper dealing with one dimensional variations in strain. In the present paper, the solution is extended to a two-dimensional deformation with radial symmetry. An experiment is described in which the surface strains produced by the impact of a bullet on a flat plate are determined from the birefringence of a surface coating taking into account the effects of strain gradients and curvature. The values of surface strain are compared with measurements made by means of a square grid inscribed on the metal surface. A procedure is suggested for determining an unknown surface strain having radial symmetry from the total birefringence of the surface coating when the change in curvature of the metal surface under load is known or can be determined separately.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Experimental mechanics 1 (1961), S. 74-82 
    ISSN: 1741-2765
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract It is known that birefringent coatings are a powerful experimental technique for the determination of surface strains of metals or other opaque bodies. In this paper the complete state of strain in such a coating is determined for an arbitrary one-dimensional variation of the displacement at the metal surface. It is shown that strain gradients or curvature of the surface have a pronounced effect on the observed birefringence, and must be taken into consideration. This can be done by means of two correction factors derived in the paper which take into account the elastic properties of the coating and its thickness. An experimental procedure is outlined for determining an unknown distribution of strain at the metal surface on the basis of the observed photoelastic pattern.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Experimental mechanics 1 (1961), S. 109-112 
    ISSN: 1741-2765
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...