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  • Artikel: DFG Deutsche Nationallizenzen  (149)
  • Digitale Medien  (149)
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 5601-5603 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The evolution of step bunching on vicinal GaAs(001) annealed at different temperatures in AsH3 and H2 ambient was studied by scanning tunneling microscopy. The results provided aspects of the evolution of step bunching from the initial to the final stage. We observed a appearance of additional step bunchings which have a peculiar azimuth of 〈210〉, 〈21¯0〉, 〈310〉, and 〈31¯0〉.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 7533-7539 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have studied the 77 K photoluminescence (PL) of undoped-AlxGa1−xAs (0.21≤x≤0.83) grown by organometallic vapor phase epitaxy. A deep broad (DB) PL band is found at 1.6–1.7 eV at a range of x from 0.21 to 0.63, with a maximum intensity at around x=0.5. Its large full width at half-maximum (∼200 meV) suggests that this emission originates from some impurity-defect complex. The Si- and C-doping dependencies of the PL reveal that the emission disappears in Si-doped n-type samples while it increases in intensity superlinearly with the hole concentration, thus, the emission center is C acceptor related. Furthermore, annealing Al0.52Ga0.48As samples in H2 flow eliminates the emission, while annealing in AsH3 flow increases the emission. Based on these results, we have considered the doping and V/III dependencies of various major point defects present in p-type GaAs and those of the combinations of the C acceptor and these defects. It is concluded that the DB band originates from the substitutional C–As antisite complex (CAs–AsGa). Mass-action rule analysis of the complex deduces a quadratic increase in the PL intensity with hole concentration, which generally explains the experimental results. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 2280-2282 
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The lattice Bhatnagar–Gross–Krook modeled fluid has an unchangeable unit Prandtl number. A simple method is introduced in this report to formulate a flexible Prandtl number for the modeled fluid. The effectiveness of this method was demonstrated by numerical simulation of the Couette flow. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1236-1238 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The idea and successful practice of a stress sensor to sense mechanical stress by an artificial skin, i.e., self-diagnosis thin film, has been realized, through the fabrication of a high-luminescence thin piezoelectric film which can reproducibly emit strong visible light upon stressing. The strongest luminescent film consists of nanosized crystallites of ZnS doped with 1.5 at. % Mn, in which Mn acts as the emitting center. The intensity of the emitted luminescence responds to stress applied directly onto the film or to the underlying material reversibly and reproducibly, so it can be used as an artificial skin to sense mechanical stress. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1639-1640 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Electrochromism was newly realized in a WO3–Pb(Zr0.52Ti0.48)O3 (PZT) system which utilized the piezoelectric property of PZT ceramics for power supply. The electric power produced by Mn-doped PZT ceramics enabled the WO3 film to color blue. High piezoelectricity with a peak voltage of 35 V and peak current of 1.2 mA on a 30 kΩ circuit was observed at a pressure of 30 MPa for the present system. This study shows the possibility to actuate the electrochromic WO3 film with PZT ceramics. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 1625-1627 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Similar step bunchings which consist of 7–9 single steps were observed by scanning tunneling microscopy on both vicinal GaAs(100) surfaces grown by metalorganic chemical-vapor deposition (MOCVD) and annealed in AsH3 atmosphere. Growth parameters, including deposition rate, layer thickness, V/III ratio, and growth temperature, did not affect the morphology of the step bunching. These results indicate that step bunching is induced during the annealing process and its surface morphology is preserved during MOCVD growth for a wide range of growth parameters.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1471-0528
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Objective To investigate the management of women with asymptomatic ovarian masses, to determine the appropriate duration of follow up, and to identify diagnostic indicators of growing cysts.Design Review of women's hospital records.Setting Tokyo Metropolitan Cancer Detection Center, Japan.Population Two hundred and twenty-five pre- and postmenopausal women with a diagnosis of ovarian cyst ≥6 cm in diameter and normal serum level of CA125, diagnosed between 1 October 1990 and 25 December 1991.Main outcome measure Change in size of cyst as shown by ultrasound.Results Seventy-five months after initial diagnosis, 29 (13%) of the masses had progressed, 31 (14%) had persisted, and 165 (73%) had regressed. One hundred and nine masses (48%) had regressed within six months of the initial diagnosis. In univariate analysis transvaginal ultrasonographic assessment of morphology findings, cyst diameter, carcinoembyronic antigen (CEA) and CA 19.9 were associated with the prognosis of the cyst. Multivariate regression analysis demonstrated that only the initial serum CA19-9 level and serum CEA level were significant predictors of ovarian masses that regressed (P for trend = 0.004 and 0.02, respectively).Conclusion Simple ovarian cysts in patients with a normal level of CA125 have a low risk for ovarian cancer. Vaginal ultrasound at six months will identify regression of most simple cysts. CA19-9 and CEA at the initial diagnosis are useful parameters to predict future regression of ovarian cysts.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background Systemic amyloidosis occurs as a result of amyloid deposition in various tissues. The amyloid fibrils in systemic amyloidosis have been reported to originate from immunoglobulin light chains. Objectives We studied the composition of amyloid fibrils from two patients with plasma cell-associated systemic amyloidosis (PASA). Methods A double immunofluorescence study of the lesional skin of PASA was undertaken. Amyloid proteins were extracted with distilled water from one case of PASA. Results The double immunofluorescence study showed that anti-λ light chain and anti-β2 microglobulin antibodies mostly reacted with the same area of amyloid deposit. Amyloid deposits from two patients with PASA who had never undergone haemodialysis showed a positive reaction with the antibodies for β2 microglobulin as well as immunoglobulin λ light chain. By the use of immunoblot assay of amyloid fibril proteins, polypeptides immunoreactive with antiγ light chain antibody (29 kDa) and with anti-β2 microglobulin antibody (12 kDa) were detected. Conclusions These results indicate that β2 microglobulin is a component of amyloid fibrils in PASA.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 144 (2001), S. 0 
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Chronic liver diseases are known to cause several skin manifestations, including cutaneous vascular changes such as spider naevus and palmar erythema. Arteriovenous haemangioma (AVH), a benign acquired cutaneous vascular lesion, has also been reported to be associated with chronic liver disease. We report here four cases of AVH in patients with chronic liver disease: (i) a 59-year-old man who had suffered from chronic active hepatitis associated with hepatitis C virus for 15 years; (ii) a 48-year-old man who had suffered from alcoholic hepatitis for 3 years and was diagnosed with liver cirrhosis 1 year ago; (iii) a 69-year-old female who had had chronic active hepatitis associated with hepatitis C virus infection for 20 years and was diagnosed with liver cirrhosis 7 years ago; and (iv) a 48-year-old man who had had chronic active hepatitis associated with hepatitis B virus infection for about 20 years. All patients showed an asymptomatic solitary dome-shaped reddish papule, 5–10 mm in diameter, on the face (first, second and third patients) or chest (fourth patient). Histopathological examination of the tumours revealed features of AVH, namely a well-circumscribed lesion composed of vascular structures of various sizes reminiscent of arteries and veins. In all four cases, elastic-van Gieson stain showed the absence of an internal elastic lamina in the thick-walled vessels as well as the thin-walled vessels. Examination of multiple sections demonstrated glomus cells and an ascending artery feeding the tumour vessels in only one case. Slight inflammatory cell infiltration was seen in the stroma of three patients while Toluidine blue staining revealed an increased number of mast cells in the stroma in all lesions. The present cases suggest that the occurrence of AVH associated with chronic liver disease is not related to any specific liver disease, but may be related to chronic liver dysfunction itself.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In order to clarify the pathomechanism of acantholysis in Hailey–Hailey disease (HHD) and Darier’s disease (DD), the distribution of desmosomal and adherens junction-associated proteins was studied in the skin of patients with HHD (n = 4) and DD (n = 3). Domain-specific antibodies were used to determine the cellular localization of the desmosomal transmembrane glycoproteins (desmogleins 1 and 3 and desmocollin), desmosomal plaque proteins (desmoplakin, plakophilin and plakoglobin) and adherens junction-associated proteins (E-cadherin, α-catenin, β-catenin and actin). A significant difference in staining patterns between intra- and extracellular domains of desmosomal cadherins and E-cadherin was demonstrated in acantholytic cells in both HHD and DD, but not in those in pemphigus vulgaris and pemphigus foliaceus samples used as controls. In acantholytic cells in HHD and DD, antibodies against attachment plaque proteins and intracellular epitopes of desmosomal cadherins exhibited diffuse cytoplasmic staining, whereas markedly reduced staining was observed with antibodies against extracellular epitopes of the desmogleins. Similarly, membrane staining of an intracellular epitope of E-cadherin was preserved, while immunoreactivity of an extracellular epitope of E-cadherin was destroyed. While the DD gene has been identified as ATP2A2, the gene for HHD has not been clarified. The dissociation of intra- and extracellular domains of desmosomal cadherin and E-cadherin is characteristic of the acantholytic cells in HHD and DD, and not of pemphigus. This common phenomenon in HHD and DD might be closely related to the pathophysiological mechanisms in both conditions.
    Materialart: Digitale Medien
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