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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 57 (1987), S. 187-195 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract We compare several algorithms for the recognition of ordered and disordered images. As image sources we use waves of the Belousov-Zhabotinskii reaction coupled to convective motion in a petri dish. This device allows reversibly the generation of periodic (ordered) and aperiodic (disordered) patterns. The best match between the parametric description and the observations is obtained by an “autodifference function”. This function is computed by summing up intensity differences over all pairs of picture elements having a given distance on the picture plane. Then, the minimum of this function is determined upon variation of the distance. This algorithm is not only efficient for the recognition of order and disorder in “machine vision”, but also plausible in biological visual perception.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1017
    Keywords: Bacteriorhodopsin ; blue membrane ; purple membrane films ; electric-field-induced states ; dielectric dispersion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Electric field induced conformational changes of bacteriorhodopsin were studied in six types of dried film (randomly and electrically oriented membranes of purple as well as cation-depleted blue bacteriorhodopsin) by measuring the frequency dependence of the optical absorbance change and the dielectric dispersion and absorption. For the purple bacteriorhodopsin the optical absorbance change induced by alternating rectangular electric fields of ±300 kV/cm altered the sign twice in the frequency range from 0.001 Hz to 100 kHz (around 0.03 Hz and 100 kHz), indicating that the electric field induced conformational change in these samples consists of, at least, three steps. Similarly, it was found for the blue bacteriorhodopsin that at least two steps are involved. In accord with optical measurements, the dielectric behaviour due to alternating sinusoidal electric fields of±6kV/cm in the frequency range from 10 Hz to 10 MHz showed two broad dispersion/absorption regions, one below 1 kHz and the other around 10–100 kHz. This suggests that the conformational change of bacteriorhodopsin is also reflected by its dielectrical properties and that it is partially induced at 6 kV/cm. Including previous results obtained by analysis of the action of DC fields on purple membrane films, a model for a field-induced cyclic reaction for purple as well as blue bacteriorhodopsin is proposed. In addition it was found that there are electrical interactions among purple membrane fragments in dried films.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Suppression of humoral antibody formation against HSV is not only induced by replicating Herpes simplex virus type 2 (HSV-2) but also by the defective strain ANG and the deletion mutant 1301 of Herpes simplex virus type 1 (HSV-1). Moreover, ts-mutants A, H, K, S, 1201 and 1208 of HSV-1 as well as some ts-mutants of HSV-2 and “defective-interfering” particles of HSV-1 after high multiplicity of infection-passages induced suppression. Treatment of infected mice with ACG reduced antibody-formation but did not result in suppression. UV-irradiation of the antibody producing strain Len of HSV-1 strongly reduces antibody formation and induces suppression. Experiments using a series of intertypic recombinants showed the suppressing activity to be spread over the whole genome of HSV-2. It is concluded that suppression is induced by more than one region of the genome of HSV-2 and by incomplete replication of HSV-1 and 2.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two and a half hours after infection with a high dose of different strains of HSV-1 which induce rounding of cells, breakdown of actin containing microfilaments can be observed. At the periphery of the cell, actin containing knob-like protuberances were visible. Later on, actin seems to be located exclusively on the surface of cells. Observations were done by immunofluorescence microscopy, scanning electron-microscopy and immunoperoxidase staining of ultrathin sections. The envelope of HSV appears to be stained by anti-actin. Strain IES produces rounding of cells at a high dose of infection before fusion proceeds at 37°C. Similar alterations were not observed with the fusing strains MP and HFEM. Incubation of infected cells at 39°C revealed strain dependent differences of the fusion activity. At 41°C no “fusion from within” of cells but only rounding was detectable. Application of tunicamycin resulted in complete inhibition of fusion by all strains. The fusion activity of some strains of HSV-1 (ANG, HFEM, and MP) was not inhibited by addition of 2-deoxy-D-glucose and 2-fluoro-deoxy-D-glucose. A variant from strain MP could be isolated, which is sensitive to the effects of 2-deoxy-D-glucose. Inhibitors of processing of glycoproteins did not affect fusion of cells.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fate of microtubules and of vimentin or keratin containing intermediate filaments during infection with fusion or rounding producing strains of herpes simplex virus (HSV) was investigated. Microtubules polymerize early after fusion of cells. However, they do not reconstitute 6–7 hours post infection (p.i.) after release of a colcemid block. Keratin and vimentin are maintained around the original nucleus still inside of recruited cells in the polykaryocyte. Cells of fibroblastic and epithelial origin fuse. Inside of polykaryocytes keratin or vimentin containing fibers seem to polymerize. Keratin is to be found in invaginations in the nuclei surrounded by the inner layer of the nuclear membrane. Anti-keratin antibodies specifically label HSV envelopes located in the cytoplasm. or outside of the cell. Controls of the procedure allowed to exclude labelling of HSV envelopes via gpE, which represents HSV induced Fc receptors. Late stages of infected cells contain thickened and condensed keratin fibers. Conversely, vimentin fibers late after infection appear to be evenly distributed and to be thin. Microtubules decay late after infection with rounding producing strains of HSV, whereas keratin and vimentin fibers are still present late after infection.
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  • 6
    ISSN: 1433-8726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Minimal percutaneous nephrostomy as a palliative urinary diversion was performed in 50 patients with advanced bladder cancer disease. The average survival time was 6.6 months, with 38% of the patients alive after 6 months. Although 88% of the patients died within one year, 2 (5%) are still alive after more than 2 years. Each case of palliative diversion is an individual one, with many different factors influencing the decision. Prolonging life cannot be an indication for diversion. Percutaneous nephrostomy in combination with other percutaneous techniques provides the urologist with excellent therapeutic tools to avoid surgery in such emergency situations as uremia or local tumor symptoms. This may offer these patients more peace in their last days of life.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1434-601X
    Keywords: 24.60.−k ; 25.30.Fj ; 27.80.+w
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The fine structure observed in high resolution inelastic electron scattering spectra for208Pb in the excitation energy range of the isoscalar giant quadrupole resonance has been analysed with a fluctuation analysis technique. The obtained density of levels as a function of excitation energyE x has then been used as a constraint for the shape and magnitude of the (radiative) background subtracted spectra subjected to a multipole decomposition. The derivedE2 strength in the region 8.0≦E x≦11.5 MeV exhausts (50 −7 +15 % of the energy weighted sum rule. TheE2 strength found is considerably larger than previously estimated from the same spectra and it is now both in shape and magnitude in good agreement with results from a recent208Pb(e, e′n) coincidence experiment.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of adjuvant-induced arthritis of the rat on central and peripheral peptide neuroanatomy was investigated by immunohistochemistry. The most striking feature of arthritic rats was the differential intensification of neuronal proenkephalin- and prodynorphin-related staining in dorsal horn. Changes were ipsilateral in monoarthritic and bilateral in polyarthritic rats as compared to controls. Opioid responsive neurons were target of substance P (SP) and calcitonin gene-related peptide (CGRP) fibers. Changes of SP and CGRP predominated in peripheral inflamed tissue and consisted of intensified immunostaining and an apparent sprouting of sensory fibers particularly around venules, in the epidermis and in areas infiltrated by immunocompetent cells. Opioid staining was absent from primary afferents but present in some immune cells of inflamed tissue. Endogenous antinociceptive opioids and pro-nociceptive/pro-inflammatory SP and CGRP may be crucial in the concerted response of the neuroimmune system to chronic inflammatory pain.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymers of α-chloroacrylate (MCA), 1-chloroethyl methacrylate (1CEMA), 2-chloroethyl methacrylate (2CEMA), 2,2,2-trichloroethyl methacrylate (trCEMA) and 1,2,2,2-tetrachloroethyl methacrylate (teCEMA) were γ-irradiated at 77 K. The primary radicals were generated by the abstraction of chlorine. They decay or change into chain end radicals upon warming up to room temperature.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical generation after γ-irradiation at 77 K and radical reactions during temperature increase are discussed for the polymers poly(2-chloroethyl methacrylate) and poly(1,2,2,2-tetrachloroethyl methacrylate), mixed with triallylisocyanurate (TAIC). After the radiation interaction radicals are generated in the ester alkyl side groups of the polymer by chlorine abstraction in both polymer/TAIC mixtures. Radical transfer to TAIC occurs during temperature increase to produce allyl radicals. Hence, the high radiation sensitivity of chlorine-containing polymers is combined with the reactivity of allyl radicals of TAIC in such polymer-TAIC mixtures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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