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  • Artikel: DFG Deutsche Nationallizenzen  (65)
  • 1995-1999  (55)
  • 1980-1984  (10)
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 6143-6149 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Er3+ singly- and Er3+/Yb3+-codoped fluorozirconate glasses were prepared. The upconversion emission intensities of the Er3+ ion around both 550 and 660 nm were measured under 800 nm excitation. The absorption band of the Yb3+ ion is located around 980 nm. Though the absorption band of Yb3+ does not interact directly with the incident light at 800 nm, both upconversion intensities around 550 and 660 nm emission increased with the increasing YbF3 concentration. We calculated the upconversion intensities around 550 and 660 nm by using rate equations and evaluated the principal upconversion mechanism in Er3+ singly- and Er3+/Yb3+-codoped samples quantitatively. We also investigated the reason for the increase of the upconversion emission intensities with the codoping of Yb3+ under 800 nm excitation. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 6262-6267 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A mechanism explaining the breakdown of dielectrics with high intrinsic inhomogeneity like natural rocks and concrete is proposed and proved experimentally. This work has a very promising industrial application in the drilling and demolition of natural and artificial solid materials by electric pulses. The mechanism includes the breakdown of gas cavities inside the dielectric and on its surface. At a very high applied voltage, the high electric field causes the breakdown in the cavities. The displacement and conduction currents flowing through a number of such cavities result in the heating of the plasma and high pressure pulse generation. The pulsed pressure results in crack formation and finally, in the destruction of a solid material. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 29-37 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The upconversion emission intensities of Er3+ ion around 550 and 660 nm in fluorozirconate glasses were measured under 800 nm excitation. Though energy transfer processes played an important role in upconversion mechanism at high concentration of ErF3, those have not been treated quantitatively. The energy transfer rates were calculated from the optical parameters assuming some distribution of Er3+ ions. We calculated the upconversion intensities around 550 and 660 nm by using rate equations. It was found that the dependence of upconversion emission intensities on the ErF3 concentration could be reproducible and the principal upconversion mechanism could be evaluated. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 26 (1999), S. 0 
    ISSN: 1365-2842
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The authors attempted to clarify the primary factors affecting the timing of the initial electromyographic discharges in the jaw depressor muscles (EMG onset). The changes in EMG onset in the inferior head of the lateral pterygoid (Lpt) and the anterior belly of the digastric muscles (Dig) were measured by varying duration of the open–close movement or occlusal force during the open–close–clench cycle (OCC). EMG onset tended to precede the beginning of the opening movement during OCC. The duration of opening and closing phase and the duration of occluding phase showed no significant correlation with the time-lag between EMG onset and the beginning of the opening movement (onset time).The mean EMG activity of the masseter muscle (Mm), corresponding to the occlusal force, showed a highly significant correlation with the onset time. The maximal opening velocity was highly correlated with the mean EMG activity of the jaw depressors before jaw opening. In conclusion, it was found that occlusal force is a major factor in EMG onset in the jaw depressors. It is suggested that smooth opening needs tooth contact with some degree of occlusal force.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The observation was carried out with an X-ray burst monitor which consists of two sets of rotating modulation collimators: two coarse modulation collimators (CMC 1,2) and a fine modulation collimator (FMC 1) with a field of view of 17.4 and 5.8 (FWHM), respectively. Positions of steady sources and ...
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 638-643 
    ISSN: 1432-2161
    Schlagwort(e): Key words Lumbar spine ; Disc space narrowing ; Radiographs ; Disc degeneration ; Instability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objective. To establish criteria for the radiographic evaluation of narrowing of the L5–S1 disc height, which varies widely with transition of the L5 vertebra. Design and patients. Nondegenerated disc heights of L3–4 to L5–S1 and the thickness and length of the L5 transverse process were measured on plain radiographs of the lumbar spine in 166 outpatients, aged 18–35 years (mean 26.3 years), in whom at least the L3–4 and L5–S1 discs both showed normal signal intensity on magnetic resonance imaging. The level of the iliac crest was recorded semiquantitatively. The disc height was expressed as a percentage of the L3–4 disc height, namely ”relative disc height”. The ratio of disc height to the sagittal diameter of the overlying vertebral body was termed the ”disc height index”. Results and conclusion. The relative disc height and disc height index of L5–S1 showed strong negative correlations with two anatomic variables, which were the relative thickness of the transverse process and the level of the iliac crest (P〈0.0001). The results of linear regression analysis suggest that narrowing of the L5–S1 disc height can be evaluated on plain radiographs alone in relation to these anatomic variables.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    International orthopaedics 5 (1981), S. 47-52 
    ISSN: 1432-5195
    Schlagwort(e): Osteoarthritis ; Collagen framework ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Des prélèvements obtenus à partir de genoux humains arthrosiques et de genoux de chien porteurs de lésions arthrosiques expérimentales ont permis l'étude de la charpente de collagène du cartilage articulaire et de l'os sous-chondral, par microscopie conventionnelle et par microscopie électronique. Dans les lésions dégénératives, les fibrilles de collagène du cartilage ont une orientation radiale, alors qu'elles sont habituellement groupées en faisceaux. En cas de lésions étendues, le cartilage présente souvent des clivages ou des fissures menant jusqu'aux couches calcifiées. Les fibrilles de collagène du cartilage arthrosique se fondent dans la plaque osseuse souschondrale, rendant la jonction ostéo-cartilagineuse irrégulière ou mal définie. L'orientation trabéculaire de l'os sous-chondral se modifie en fonction de l'altération du cartilage articulaire. Ces modifications réactionnelles montrent que, même au niveau ultrastructural, l'architecture de l'os sous-chondral reflète la dégénérescence cartilagineuse.
    Notizen: Summary Specimens obtained from human osteoarthritic knee joints and dog knees with experimentally induced osteoarthritis were used to study the collagenous framework of articular cartilage and subchondral bone in relation to osteoarthritic changes using scanning electron microscopy and light microscopy. Degenerative articular cartilage in osteoarthritic joints showed radial orientation of the collagen fibrils, which were usually discernible as fibrillar bundle formations. Cartilage with extensive lesions often showed cleavages or fissures down to the calcified layer. The cartilagenous collagen fibrils in osteoarthritic specimens merged into the subchondral bone plate making the tidemark and the osteochondral junction irregular or obscure. The trabecular orientation of subchondral bone changed with alteration in the articular cartilage and with reactive changes in the subchondral bone, showing the effect of cartilaginous degeneration on its ultrastructure.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 125 (1999), S. 646-652 
    ISSN: 1432-1335
    Schlagwort(e): Key words Osteosarcoma ; CD44 ; Immunohisto-chemistry ; Prognosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The standard form of CD44 (CD44H) is a transmembranous glycoprotein, widely distributed on a variety of human lymphoid cells, epithelial cells and tumours. CD44 has many variant forms, which are generated by alternative splicing. In recent years, CD44 has been reported to be related to the degree of tumour differentiation, tumour cell invasion, and metastasis. We investigated 44 tumour specimens in 39 patients with osteosarcoma immunochemically to analyse the expression of CD44 standard (CD44H) and variant exon-encoded gene products (CD44v3, v4, v5, v6, v7, v9, and v10). Furthermore, the relationship between CD44 expression and the clinical outcome of patients with osteosarcoma was analysed. Membrane accentuation and exclusive cytoplasmic reactivity were analysed as separate staining patterns. Tumour cells and some multinucleated giant cells were markedly stained. CD44H, v3, v4, v5, v6, v7, v9, and v10 were expressed in 85%, 49%, 54%, 59%, 46%, 5%, 28%, and 10% of the specimens respectively. The cumulative 5-year metastasis-free survival was 58% in CD44v6-negative cases and 24% in CD44v6-positive cases (P=0.046). However, the cumulative 5-year metastasis-free survival was not significantly different between cases positive and negative for other variants of CD44. Multivariate analysis (Cox proportional-hazard model) with CD44v6 expression (positive or negative), chemotherapy (intensive or non-intensive), tumour site (proximal or distal), and age (at least 30 years or less than 30 years) showed that expression of CD44v6 and chemotherapy were important prognostic factors in patients with osteosarcoma. Overexpression of CD44 isoforms containing variant v6 is correlated with poor prognosis in patients with osteosarcoma.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    International orthopaedics 20 (1996), S. 227-232 
    ISSN: 1432-5195
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé. L’évolution de la maladie chez 8 patients présentant une dysplasie fibreuse diffuse suivie plus de 10 ans (moyenne 19,5 ans) a été annalysée rétrospectivement. Un patient avait un syndrome d’Albright. Deux des trois lésions du fémur proximal chez les patients qui eurent soit un curetage et une greffe osseuse, soit une ostéotomie avant la puberté ont été le siège d’une aggravation de la déformation pendant la croissance. Une des deux lésions du fémur proximal chez des patients qui eurent un curetage et une greffe osseuse après l’âge de 18 ans, furent le siège d’une déformation. Deux lésions du tibia qui ont été opérées à l’âge de 1 et de 30 ans sont ensuite restées stables. L’aspect histologique était plus actif dans les lésions des patients jeunes que chez ceux ayant terminé leur croissance.
    Notizen: Summary. Eight patients who had polyostotic fibrous dysplasia were followed up for more than 10 years. One had the Albright syndrome. Two of 3 proximal femoral lesions which were treated before puberty by either curettage and bone grafting or by osteotomy, developed progressive deformity during the growth period. One of 2 proximal femoral lesions treated by curettage and bone grafting after the age of 18 also developed a deformity. Two tibial lesions operated on at the age of one and 30 years remained stable. The histological findings showed more active lesions in young patients compared with adults.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    International orthopaedics 23 (1999), S. 182-183 
    ISSN: 1432-5195
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé  3 patients opérés pour tumeur maligne de l’extrêmité proximale du fémur ont eu l’implantation d’une endo-prothèse avec reconstruction de la capsule articulaire et des abducteurs par un filet synthétique.
    Notizen: Abstract  Three patients with malignant bone tumors of the proximal femur underwent implantation of an endoprosthesis with reconstruction of the joint capsule and hip abductors using artificial mesh.
    Materialart: Digitale Medien
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