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  • 1
    Digitale Medien
    Digitale Medien
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 0-0 
    ISSN: 1600-5759
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 6 (1999), S. 749-751 
    ISSN: 1600-5775
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 69 (1999), S. 115-118 
    ISSN: 1432-0630
    Schlagwort(e): PACS: 81.15.F; 71.24; 81.20.E
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract. The effect of ambient Ar pressure on the mean diameters and aggregate state of cobalt (II,III) oxide nanoparticles prepared by pulsed-laser ablation is investigated. TEM images show that the mean diameters of the primary nanoparticles are in the range 1.2–3.2 nm when the ambient pressure is varied from 13.3 Pa to 13.3 kPa. With the increase of Ar pressure, the mean diameters of the primary nanoparticles increase and show a maximum at a pressure of 100 Pa. A further increase of ambient pressure results in a decrease in mean diameter of the primary nanoparticles. In the pressure range from 267 Pa to 2.67 kPa, the mean diameters of the prepared nanoparticles are almost constant, and aggregated nanoparticles are observed. Above 2.67 kPa, aggregated Co3O4 particles dominate the ablated product and the mean diameter of the primary nanoparticles decreases with increasing ambient pressure. A dynamic process is suggested to explain the experimental results.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Archive of applied mechanics 69 (1999), S. 379-392 
    ISSN: 1432-0681
    Schlagwort(e): Key words Continuum damage ; thermodynamics ; dissipative process
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Summary A dissipative flow model is presented to describe dissipative deformation processes in a macroscopic solid continuum. Dissipative process may consist of material plasticity, material damage and other intrinsic mechanical phenomena represented by internal variables. The concept of a dissipative surface is introduced in the paper to distinguish between conservative and dissipative processes. Conventional plastic yielding and damage initiation are expressed by a unique condition which may else include other possible intrinsic mechanical dissipations. The proposed model is based on the principles of irreversible thermodynamics and the minimum free energy theorem. A modified material stability postulate, modified Drucker's postulate, in thermodynamic stress space is also used to obtain the same results.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1420-9071
    Schlagwort(e): Key words. AP-1; ERCC-1 mRNA; ERCC-1 gene transcription; nucleotide excision repair; ovarian cancer; phorbol ester.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. ERCC-1 is an essential gene in the nucleotide excision repair pathway, and may be essential for life. However, the mechanism of transcriptional activation and regulation of ERCC-1 gene expression is unclear. We therefore investigated the effect of the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the expression of the ERCC-1 gene in A2780/CP70 human ovarian carcinoma cells. TPA induced a four- to sixfold increase in steady-state ERCC-1 messenger RNA (mRNA) levels that was time- and concentration-dependent. Nuclear run-on experiments demonstrated that the rate of transcription of ERCC-1 was approximately 2.8-fold higher in TPA-treated cells than in the controls. TPA stimulation of A2780/CP70 cells also resulted in a rapid but transient induction of c-jun and c-fos as determined by Northern and Western blot analyses, which peaked about 2 h before the peak in ERCC-1 expression. Electrophoretic mobility shift assays of nuclear extracts from TPA-treated cells revealed an increase in DNA-binding activity specific for the AP-1-like binding site in the 5′-flanking region of ERCC-1. c-Jun and c-Fos proteins were confirmed to be the components of the activated AP-1 complex by supershift analysis. The increase in AP-1 activity occurs immediately before the increase in ERCC-1 transcription. The increase in AP-1 DNA-binding activity and the increase in ERCC-1 mRNA expression were prevented by pretreatment with cycloheximide. These data suggest that AP-1 may contribute to the upregulation of ERCC-1 in response to TPA in human ovarian cancer cells.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Structural optimization 18 (1999), S. 67-73 
    ISSN: 0934-4373
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract In a finite element analysis (FEA), the contours of element von Mises stress and stiffness sensitivity number are found to be very similar. This paper shows there to be an equivalence between the von Mises stress criterion and the stiffness criterion for element elimination or addition in evolutionary structural optimization. The examples presented demonstrate the same resulting topologies during the evolving process using the two “different” criteria. The effect of numerical errors on topology is also investigated. It is concluded that the optimized topologies of a structure using the fully stressed criterion and the minimum compliance or maximum stiffness criterion are equivalent.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-2072
    Schlagwort(e): Key words Oxytocin ; Growth hormone ; Ipsapirone ; Serotonin (5-HT) ; 5-HT1A receptor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objective: The present study investigated whether administration of a 5-HT1A receptor agonist would increase growth hormone (GH) and oxytocin levels in normal human subjects, and whether the responses would be modified according to the age and gender of the subjects. Methods: Ipsapirone (0.3 mg/kg body weight), or placebo was administered to 30 normal subjects (14 males, 19–74 years and 16 females, 22–69 years) using a randomized, double blind design. Results: Stimulation of GH secretion by ipsapirone was significantly greater in male compared to female subjects, with no apparent effect of age. Oxytocin secretion was not stimulated by ipsapirone compared to placebo in any of the groups. Conclusions: The effects of gender and age on the degree of stimulation of GH secretion by 5-HT1A agonists in human subjects differ from their effects on secretion of the hormones ACTH and cortisol. A higher dose of ipsapirone is required to stimulate oxytocin secretion in normal human subjects.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-2013
    Schlagwort(e): Barnacle Central-helix troponin C Contraction Mutagenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. To examine the importance of the central α-helix of troponin C (TnC) we have bacterially expressed one of the isoforms of barnacle TnC (BTnC2), BTnCWT, but without the aspartate residue at position 80 in the central helix (BTnC80–). This manipulation is expected to produce an approximately 100° axial rotation of the C-domain with respect to the N-domain, and a net charge change of –1. BTnC80– mutant was able to restore force to TnC-depleted skinned barnacle myofibrillar bundles to a greater extent than wild-type protein (≅170%). Competition experiments between BTnC80– and BTnC2–4-, a mutant lacking both of the calcium-specific sites (sites II and IV), shows that deletion of a single amino acid in the central helix results in a protein with increased affinity for the thin filament and one that is bound preferentially compared to BTnC2–4- when at equimolar concentrations.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-0800
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Archives of virology 144 (1999), S. 1739-1749 
    ISSN: 1432-8798
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary.  In order to understand the evolutionary relationships between different genome types of adenovirus serotype 7, the nucleotide sequences of the hexon loops 1 and 2 from seven genome types have been determined. Their amino acid sequences comprising 473 to 476 residues were consequently analysed. The pairwise comparison of the sequences from seven genome types revealed the existences of two genome type clusters (GTCs). GTC1 includes Ad7p and Ad7p1, and GTC2 contains Ad7b, Ad7c, Ad7d, Ad7g and Ad7h. The amino acid similarity was 98.3–99.8% within a cluster and 93.0–94.5% between two clusters. However, the average amino acid similarity among 16 different human adenovirus serotypes was only 65% with two exceptions, 92.7% between Ad4 and Ad16, and 86.8% between Ad3 and Ad7. Two variable regions were found in the loops 1 and 2. A deletion of nine nucleotides was detected in the variable region 1 of all members of GTC2. According to the alignment of nucleotide sequences, two short direct repeats were found at the deletion junctions, indicating that GTC2 may be derived from GTC1 by illegitimate recombination. In variable region 2, the substitution from 443Leu (Ad7b) to Gln (Ad7d) dramatically affected the hydropathic characters of this region. The region surrounding 443Leu (Ad7b) manifested hydrophobicity whereas the region surrounding Gln (Ad7d) manifested hydrophilicity.
    Materialart: Digitale Medien
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