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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 2185-2196 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A series of InGaAs films, compressively or tensilely strained, were grown on (001)InP substrates at 490 °C by gas source molecular beam epitaxy. Compressively strained (−0.5%) (and lattice matched) layers were morphologically stable, but layers grown under tension (+0.5 to +0.6% strain) developed facets on (113)A or (114)A planes. In the first stages of growth of films under tension, and throughout all stages of growth for the compressively strained films, a fine scale (10 nm wavelength) composition modulation was found in the [110] direction. In the later stages of growth of films under tension, the regions of composition segregation were confined to the peaks and valleys of the faceted surface. Regions of high and low stress concentration (the valleys and the peaks) exhibit In/Ga ratios higher or lower, respectively, than the flat faceted surfaces. The elastic strain energy built into the film, associated with the [110] composition modulation, depends on the ratio of the modulation wavelength to film thickness. In films grown under tension, facet coarsening provides a means for the system to reduce the strain energy associated with segregation. Faceting (and facet coarsening) leads to a reduction in the misfit strain energy stored in the film. However, an analysis of the first stages of faceting shows that faceting cannot be explained as a roughening transition. © 1997 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 82 (1997), S. 764-771 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Co–Ag granular films having various Co grain sizes are prepared by rf sputtering under various sputtering conditions. The Co grain sizes are derived from the magnetization curves by dividing them into ferromagnetic and superparamagnetic components. As the Co content decreases, the radii of the superparamagnetic Co grains, rg, decrease and the distances between the Co grains, tg, increase. The magnetoresistance is proportional to the volume density of superparamagnetic grains or related to krg3 exp(−tg/l) with k=3.8×102 μΩ/cm2 and l=20 Å, implying that the giant magnetoresistance is caused by the spin-dependent scattering in the inner part of the superparamagnetic Co grains as well as at the grain surfaces. Furthermore, it is found that the extraordinary Hall effect arises mainly from the side jump mechanism, and that significant perpendicular magnetic anisotropy appears in the Co composition range between 40 and 70 at %. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1365-2826
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We have examined alterations in the hypothalamo-pituitary GH-somatic growth axis and the hypothalamo-pituitary LH-ovarian axis in a line of transgenic ICR mice expressing human GH (hGH) under the influence of the whey acid protein promoter. Transgenic female mice weighed twice as much as control females and were infertile. The size of the anterior pituitary (AP) was that of the controls. In transgenic mice, acinar cells in the mammary and mandibular glands displayed hGH-immunoreactivity, and plasma hGH was detected by radioimmunoassay. In the medial basal hypothalamus (MBH) of transgenic females, the immunoreactive-GHRH level was decreased (P〈0.01). There was a corresponding reduction in the number of GHRH-immunoreactive neurons in the arcuate nucleus (ARC) and in the immunostaining of GHRH nerve terminals in the median eminence. The level of somatostatin (SRIH) in the MBH was increased (P〈0.05), and SRIH-immunoreactive neurons in the periventricular nucleus (PeV) were increased in size and number in transgenic mice. The MBH level of LHRH in transgenic animals was greater (P〈0.01) than in controls, although there was no apparent difference in the number of LHRH-immunoreactive neurons or in LHRH level in the preoptic area. There are fewer SRIH- and LHRH-immunoreactive neurons in the ARC in transgenic mice. Cells in the AP for GH, PRL, and LH were fewer in transgenic mice. The ovary suffered disturbance of follicular development and of corpora lutea formation.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-1076
    Schlagwort(e): Key words Skeletal dysplasia ; Osteopathia striata ; Short stature ; Dysmorphic facies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report two sporadic cases of a hitherto undescribed skeletal dysplasia with short stature and characteristic facies. The present patients, a 6-year-old girl and a 15-year-old boy, were almost equally affected. Craniofacial anomalies included a sloping forehead, bitemporal bulging, sparse medial eyebrows, a prominent nasal bridge, hypertelorism, proptosis, a beaked nose, hypoplastic alae nasi and a pointed chin. Shallow orbits, short anterior cranial fossae and bitemporal bossing found on skull radiograph corresponded with the facial dysmorphism. Thickening of the dorsum sellae was another hallmark in the skull. Skeletal survey revealed mild osteopenia, interpediculate narrowing of the lumbar spine with short neural arches and, most important, osteopathia striata of the long tubular bones. There was no sclerosis of the craniofacial bones. The clinical and radiological findings in the present patients were overall inconsistent with those of previously known skeletal dysplasias and congenital malformation syndromes, which possess osteopathia striata as a cardinal feature. Conclusion The unique clinical and radiological constellation of our patients constitutes a hitherto unknown bone dysplasia.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-1076
    Schlagwort(e): Key words Hypoparathyroidism ; 22q11 deletion ; DiGeorge syndrome ; Graves disease ; Idiopathic thrombocytopenic purpura
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The phenotypes of chromosomal 22q11.2 microdeletion are quite variable among individuals and hypoparathyroidism (HP) constitutes a definite portion of the clinical spectrum. For the correct diagnosis and pertinent follow up of the HP children due to del22q11.2, we tried to delineate the clinical characteristics of such patients. By employing fluorescence in situ hybridization (FISH) to all the patients diagnosed as HP in our clinic, ten possessed the 22q11.2 microdeletion. Among them, the incidence of cardiac defect (5/10), recurrent infection (1/10) and cleft palate (1/10) was modest. Additionally, seven of them had been diagnosed as HP during the infantile period, when their facial abnormality and intellectual problem had not become evident. Notably, two patients were complicated by Graves disease, while the association of idiopathic thrombocytopenic purpura was also observed in two girls. Conclusion HP due to del22q11.2 may be misdiagnosed as idiopathic, especially in an infant who lacks apparent complications like cardiac anomaly. They should be closely followed up for auto-immune complications.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Surgical endoscopy and other interventional techniques 11 (1997), S. 287 -289 
    ISSN: 1432-2218
    Schlagwort(e): Key words: Laparoscopic intragastric surgery (LIGS) — Gastric leiomyoma — Leiomyosarcoma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Laparoscopic intragastric surgery (LIGS) was performed on a 63-year-old man with a gastric leiomyoma adjacent to the cardia. Because the tumor was about 5 cm in maximum diameter and showed ulceration, the possibility that the tumor was a leiomyosarcoma could not be ruled out preoperatively. Conventionally, major surgery has been performed on patients with a tumor located near the cardia, although it was not always malignant. Enucleation by LIGS enabled us to avoid excessive invasiveness and provided a favorable result. LIGS may be an appropriate new, minimally-invasive operation for gastric myogenic tumors and should be considered for such cases.
    Materialart: Digitale Medien
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