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  • 1
    Electronic Resource
    Electronic Resource
    Elastic properties of nanoparticle chain aggregates of TiO2, Al2O3, and Fe2O3 generated by laser ablation (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 63-73 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Previous studies have shown that nanoparticle chain aggregates (NCA) of titania are elastic [S. K. Friedlander, H. D. Jang and K. H. Ryu, Appl. Phys. Lett. 72, 1 (1998)]. The NCA were a few tenths of a micron long and composed of (approximately) 7 nm primary particles. They were produced by thermal decomposition of titanium tetraisopropoxide vapor in nitrogen. The goal of this study was to see whether the elastic behavior depends on (a) the material properties, (b) primary particle size, and (c) method of NCA formation. For this purpose, titania, alumina, and iron oxide NCA were generated by laser ablation. Rotating metal foil targets were mounted in a small cylindrical chamber and exposed to an excimer laser beam. The resulting aerosol was swept out by an oxygen stream. The generator was operated to produce NCA with similar mobility diameter and primary particle size. The NCA were deposited on the carbon or formvar films of an electron micrograph grid. Under the electron beam a hole develops in the carbon film in the neighborhood of the deposited NCA. The NCA then stretch and contract as described in our earlier study [S. K. Friedlander, H. D. Jang and K. H. Ryu, Appl. Phys. Lett. 72, 1 (1998)]. The titania, alumina, and iron oxide NCA generated by laser ablation all showed elastic behavior for primary particles smaller than about 10 nm. However, titania NCA composed of 36 nm primary particles did not exhibit elastic behavior indicating that very small primary nanoparticles are needed for this phenomenon to occur. The small scale stretching and contraction of chain segments were studied by measuring changes in the bond angles between adjoining particles and in the lengths of the segments studied. The elastic behavior is probably associated with local folding of chain segments due to van der Waals forces. Under tension, folded chains straighten but when the tension is relaxed, folds tend to reform but not reversibly. Rotation and sliding probably occur at the boundaries between particles during stretching. We hypothesize that elastic behavior is a general property of NCA composed of transition metal oxides with primary particles smaller than 10–15 nm; the phenomenon has now been observed for NCA produced in two ways, thermal decomposition and laser ablation. These phenomena may play a role in the action of nanoparticle additives such as fumed silica and carbon black used to improve the properties of rubber. NCA elasticity may also contribute to the ductile properties of nanoparticle compacts. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371827
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  • 2
    Electronic Resource
    Electronic Resource
    High-dose intravenous immune globulin is also effective in linear IgA disease (2000)
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 142 (2000), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.2000.03395.x
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  • 3
    Electronic Resource
    Electronic Resource
    Identification of differentially expressed genes in models of melanoma progression by cDNA array analysis: SPARC, MIF and a novel cathepsin protease characterize aggressive phenotypes (2003)
    Oxford, UK : Munksgaard International Publishers
    Experimental dermatology 12 (2003), S. 0 
    Details
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  Currently, the scale and consistency of changes of gene expression profiles in models of melanoma progression are largely unknown. Therefore, we investigated siblings of cell lines of malignant melanomas (MM), which have been selected by nude mouse passages for (a) increased tumorigenicity (local ECM-independent growth), (b) metastatic potential, or (c) selected for increased invasiveness using the Boyden chamber. cDNA array analysis surveying more than 27.000 transcripts per cell line showed that 1.5–2.8% of all detectable transcripts were consistently differentially regulated during the selection processes in those models. Using array analysis, we identified 33 individual transcripts that exhibited significant differential hybridization paralleling the increased aggressiveness of the selected progeny. Because some of those genes could play a significant functional role in the progression of MM, we additionally proved their regulative pattern using Northern blotting. Among others, progressive overexpression of osteonectin/SPARC, a molecule that is known to be involved in tissue remodeling and angiogenesis, was found in the selected offspring from all three experimental models and may therefore be considered as a potential marker for aggressive MM as well as a promising therapeutic target. We further show that the selection of MM cells for increased ECM-independent local growth was accompanied by overexpression of macrophage migration inhibiting factor (MIF), an important modulator of both cell cycle progression and angiogenesis, and cathepsin Z, a novel member of the family of matrix degrading proteinases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0906-6705.2003.00082.x
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  • 4
    Electronic Resource
    Electronic Resource
    Spectral dependence of flavonol and betacyanin accumulation in Mesembryanthemum crystallinum under enhanced ultraviolet radiation (2002)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 25 (2002), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mesembryanthemum crystallinum L. (Aizoaceae) is a drought- and salt-tolerant halophyte that is able to endure harsh environmental conditions. Upon irradiation with high light irradiance (1200–1500 µmol m−2 s−1) it displays a rapid cell-specific accumulation of plant secondary metabolites in the upper leaf epidermis; a phenomenon that is not detectable with salt or drought treatment. The accumulation of these compounds, the betacyanins and acylated flavonol glycosides, increases if the plants are exposed to polychromatic radiation with a progressively decreasing short-wave cut-off in the ultraviolet range. The response is localized in the epidermal bladder cells on the tips of young leaves and epidermal layers of fully expanded leaves. It is demonstrated that the accumulation of flavonols and betacyanins can be described by a weakly sigmoid dose function in combination with an exponential decrease of the response function of the plant with increasing wavelength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2002.00895.x
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  • 5
    Electronic Resource
    Electronic Resource
    Induction of Hsp90 protein expression in malignant melanomas and melanoma metastases (2004)
    Oxford, UK; Malden , USA : Munksgaard International Publishers
    Experimental dermatology 13 (2004), S. 0 
    Details
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  The heat-shock protein Hsp90 has been shown to be essential for the functional integrity of the telomerase complex. The telomerase activity is enhanced in melanoma and stabilizes the chromosomal integrity in proliferating cells. Furthermore, overexpression of Hsp90 induces silencing of point mutations in transcription factors which, otherwise, would result in a loss-of-function phenotype. In melanocytic lesions there is a higher risk of mutations caused by the enhanced proliferation in melanocytic cells. By analyzing microdissected melanocytic tumors by semiquantitative PCR, we demonstrate an overexpression of Hsp90 mRNA in malignant melanomas (10/14) and in melanoma metastases (6/6) as well as in melanoma cell lines (9/9) when compared with melanocytic nevi (2/9). These results could be confirmed on protein level by immunohistochemistry. While melanocytic nevi show discrete Hsp90 expression only in a minor fraction (2/9), malignant melanomas and metastases show a positive Hsp90 immunohistochemistry in the majority of cases; (7/9) and (13/14), respectively. In addition, by analyzing melanoma metastases by flow cytometry we show that Hsp90 is expressed on the surface of tumor cells (7/8). From these data we conclude that Hsp90 is present in advanced malignant melanomas and may have a stabilizing effect on the cellular functions in proliferating cells of melanocytic lesions and could thereby be a prerequisite for the tumor progression. As Hsp90 is expressed on the cell surface, it might also be a potential immunorelevant target structure for immunotherapy of melanoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0906-6705.2004.00114.x
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  • 6
    Electronic Resource
    Electronic Resource
    Optimierte Therapie des spastischen Syndroms durch Kombination von intrathekalem Baclofen mit Botulinumtoxin (2000)
    Springer
    Der Nervenarzt 71 (2000), S. 1007-1011 
    Details
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Spastizität ; Intrathekale Baclofengabe ; Botulinumtoxin ; Keywords Spasticity ; Intrathecal baclofen ; Botulinumtoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Intrathecal administration of baclofen has proved to be an effective treatment of spasticity related to CNS damage. Especially patients with spinal spasticity due to traumatic spinal cord injury or transverse myelitis showed a dramatic reduction of spasticity and improvement of their Ashworth scores. The results are, however, often disappointing in patients with muscular hypertension of the extensor muscles, which is frequently found in patients with multiple sclerosis or cerebral hypoxia. In the latter, using intrathecal baclofen may be restricted by serious side effects. Botulinumtoxin A is widely used in patients with various forms of dystonia. It has also been studied in spastic disorders, where local injections were valuable in relieving focal spasticity in hemiparetic patients and in infantile cerebral palsy. It is used only cautiously in severe paraspasticity. The case reports of 4 patients with incomplete and complete paraparesis due to spinal cord injury, neurodegenerative pyramidal disorder, and cerebral hypoxia demonstrate that a combination of intrathecal baclofen and botulinumtoxin A can improve clinical benefits and reduce side effects.
    Notes: Zusammenfassung Die intrathekale Dauerapplikation von Baclofen stellt nicht selten bei ausgeprägten spastischen Syndromen die einzig wirksame Therapieform dar. Ein Benefit ist besonders bei Patienten mit spinalem Läsionsort und vordergründiger Beugespastik der Beine zu erwarten, der Effekt ist häufig enttäuschend bei dominierender Streckspastik und bei zerebral bedingten Spastikformen. Darüber hinaus kann der Einsatz durch relevante Nebenwirkungen limitiert sein. Als weitere Therapiealternative ist in den letzten Jahren der Einsatz von Botulinumtoxin propagiert worden, allerdings ergibt sich bei kritischer Wertung eine sinnvolle Indikation, mit Ausnahme der infantilen spastischen Zerebralparese, überwiegend bei umschriebenen distal lokalisierten spastischen Fehlstellungen. An 4 Patientenbeispielen (inkomplettes zervikales Querschnittsyndrom, komplettes thorakales Querschnittsyndrom, Systemdegeneration der Pyramidenbahn und zerebrale Hypoxie) wird demonstriert, dass die Kombination von intrathekaler Baclofenapplikation und lokalem Botulinumtoxin zu einer Optimierung der Behandlung unter pflegerischen aber auch funktionellen Aspekten und zu einer Ausweitung der Indikation führen kann, die destruierende operative Eingriffe vermeiden hilft. Durch Dosiseinsparungen sinkt die Nebenwirkungsrate erheblich.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001150050700
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