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  • 1995-1999  (4)
  • 1975-1979  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 305-307 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A reliable process has been developed for the fabrication of multilevel single-electron tunneling (SET) devices. Using this process, we have fabricated SET devices with Au-SiO-Al and Al-AlOx-SiO-Al overlap capacitors. The SET transistors exhibit voltage gain and, despite the complex device structure, have a low charge noise (7×10−5e/(square root of)Hz). Moreover, the use of overlap capacitors in SET devices results in a reduction of cross capacitances down to 8%. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 2014-2016 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A single-electron tunneling transistor has been directly coupled on-chip to a high electron mobility transistor. The high electron mobility transistor (HEMT) is used as an impedance matching circuit with a gain close to unity. The HEMT transformed the 1.4 MΩ output impedance of the single electron tunneling (SET) transistor by two orders of magnitude down to 5 kΩ, increasing its bandwidth to 50 kHz. This circuit makes it possible to observe the motion of individual electrons at high frequencies. The requirements for the bandwidth in high frequency applications is discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The presence of calcitonin and of carcinoembryonic antigen (CEA) was studied in six cases of medullary carcinoma of the thyroid using an immunoperoxidase technique. In five cases the material was obtained surgically and in one at autopsy. Tissue from primary tumours as well as from metastases was studied. Calcitonin and CEA were identified within all the tumours studied, although their pattern of distribution and staining intensity varied both within the cells and within the tumour. Some parts of the tumour contained both CEA and calcitonin, while others stained positively only for one of these substances. In some parts of the tumour there was no positive staining for either substance. Within the cells, CEA showed a typical linear distribution along cell surfaces, while calcitonin showed a more even cytoplasmic distribution and the deposits were more granular. Normal tissue surrounding tumour deposits did not show positive staining. It is considered that cells of medullary carcinoma of the thyroid contain both calcitonin and CEA. Identification of CEA and calcitonin in tumour tissue can be used as a diagnostic aid to identify medullary carcinoma of the thyroid. It is considered that these substances are being produced by this tumour and can be used as tumour markers.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-069X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 17 Patienten mit DH wurden vielfältige Duodenum- und Jejunum-Biopsien verrichtet. Die Dünndarm-Biopsien aller dieser Patienten zeigten histopathologische Änderungen, die cöliakie-ähnlich waren. Vierzehn dieser Patienten hielten eine glutenfreie Diät (GFD) während mehr als 8 Monaten. Bei allen untersuchten Patienten, die Diät hielten, verbesserten sich die Dünndarmerscheinungen. Die Dosierung von Dapsone, nötig für die Kontrolle der Hauterscheinungen, konnte reduziert werden um mehr als 50% bei 4 Patienten, und 5 andere Patienten, die die glutenfreie Diät auch hielten, brauchten diese Dapsone nicht mehr. Die Immunoglobulin enthaltenden Zellen in der Lamina propria wurden gezählt bei 8 Patienten, die nicht eine GFD hielten, bei 6 Patienten mit dieser GFD und bei 8 gesunden Kontroll-Personen. Die Zahl der IgA, IgM und IgG enthaltenden Zellen hat bei den meisten der DH-Patienten, die keine GFD hielten, zugenommen. Die Zahl der IgM enthaltenden Zellen bei den DH-Patienten, die eine GFD hielten, war dieselbe wie die Zahl dieser IgM enthaltenden Zellen bei den gesunden Kontroll-Personen. Aus dieser Untersuchung könnte man schließen, daß Gluten hauptsächlich eine IgM-Stimulierung in der Lamina propria hervorruft.
    Notes: Summary In 17 patients with DH, multiple duodenal and jejunal biopsies were performed. In all patients the small-intestinal biopsy-specimens showed histopathological changes compatible with coeliac disease. Fourteen of the patients maintained a gluten-free diet (GFD) for more than 8 months. The small-intestinal lesions improved in all patients investigated during the GFD. The dosage of Dapsone needed to control the skin lesions could be reduced by more than 50% in 4 patients and the Dapsone could be stopped in 5 other patients on GFD. The immunoglobulin-bearing cells in the lamina propria were counted in 8 patients not on a gluten-free diet, in 6 patients on gluten-free diet, and in 8 healthy controls. The numbers of IgA-, IgM- and IgG-bearing cells were increased in most of the DH patients who were not on a gluten-free diet. The number of IgM-bearing cells in the DH patients who were on a gluten-free diet was the same as that in the control group. This may indicate a mainly IgM response in the lamina propria induced by gluten.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of different fixation methods on the results of immunoperoxydase staining of immunoglobulin and gastrin producing cells in gastric and duodenal mucosa was investigated. An indirect method was used on paraffin sections. It appeared that that fixatives containing sublimate gave the most consistent results, a sublimate-formaldehyde mixture being the best.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In tissue of rats with disseminated intravascular coagulation, fibrin microthrombi can be sensitively detected by immunohistochemical methods, using antisera against rat fibrinogen or fibrin monomer. An indirect immunoperoxidase procedure on paraplast-embedded sections yields best results with regard to the morphology of the thrombi and their localization in the tissue. Only fibrillar immunoreactive material, oriented lengthwise in the vessels, should be regarded as microthrombi formed in vivo.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Annals of oncology 8 (1997), S. 1023-1029 
    ISSN: 1569-8041
    Keywords: double-staining ; glioma ; growth factors ; immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Growth factors play a role in proliferation and motility of malignant glial cells, through autocrine and paracrine mechanisms. Also, proliferation of non-tumour cells, e.g., endothelial cells, is likely to be controlled by growth factors. Several growth factors with their appropriate receptors can be involved, but studies on tissue specimens evaluating this in glioma are rare. Materials and methods: We evaluated the potential role of Transforming growth factor-α (TGF-α) and Epidermal growth factor receptor (EGF-R), the Platelet-derived growth factor A- and B-chain (PDGF-A and PDGF-B) and its receptors (PDGFRα and PDGFRβ), and basic fibroblast growth factor (bFGF) in gliomas by analysing 86 of these tumours on the single cell level for the presence of immunoreactive growth factors and receptors. In a few cases double-staining experiments were done to directly visualize co-expression of factor and receptor. Results: Multiple growth factors and their receptors are present in astrocytic tumours; the higher the grade, the more growth factors and the more positive cells are found. Oligodendroglial tumours and pilocytic astrocytomas showed little expression. Autocrine and paracrine mechanisms were frequently possible in the astrocytic tumours, often more than one loop could be involved. Interestingly, it was also frequently possible that non-tumour cells produced a growth factor for which the tumour cells expressed the receptor. Conclusions: Multiple growth factors appear to be involved in astrocytic tumours, with frequent autocrine and paracrine loops. Expression of these molecules seems to increase with increasing grade. The results argue for a contribution of non-tumour cells to the growth of a tumour.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 40 (1995), S. 609-614 
    ISSN: 1573-2568
    Keywords: serology ; gastritis ; Helicobacter pylori ; healthy volunteers ; pepsinogens ; gastrin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study was undertaken in healthy volunteers to determine the relation between serum levels of pepsinogen A, pepsinogen C, pepsinogen A:C ratio, and gastrin on the one hand and histology of the gastric mucosa on the other. The grade of gastritis was scored separately for antral and fundic mucosa by three different classifications: Whitehead, activity, and the Sydney score. Among 48 healthy volunteers studied, 17 were found to have gastritis according to the criteria of Whitehead. Fourteen of these 17 subjects with gastritis hadH. pylori in gastric biopsies. In all 48 subjects serum pepsinogen A (r=0.298−0.506;P〈0.01−P〈0.05), pepsinogen A:C ratio (r between −0.377 and −0.495;P〈0.001−P〈0.05) and gastrin (r=0.38−0.695;P=0.007−P〈0.01) were significantly correlated to the severity of both antral and body gastritis as assessed by all three classifications. In contrast, there was no significant correlation between serum pepsinogen C and any of the gastritis scores. When the 17 subjects with gastritis were analyzed separately, there were no correlations between the parameters studied and gastritis of the antrum. Regarding the corpus mucosa, serum PgA correlated significantly with the activity score (r=0.520;P=0.03), weakly with the Sydney score (r=0.465;P=0.06), but not with the Whitehead score. Serum PgC correlated with the Whitehead (r=0.555;P=0.02) and Sydney score (r=0.523;P=0.03), but only weakly with the activity score (r=0.441;P=0.08). The pepsinogen A:C ratio showed only a weak inverse correlation with the Whitehead gastritis score (r=−0.471;P=0.06), but not with the two other scores. Serum gastrin was significantly correlated with the Whitehead (r=0.634;P=0.006) and the Sydney score (r=0.501;P=0.04), but not with the activity score of the fundic mucosa. It is concluded that among healthy volunteers with gastritis, serological parameters are only correlated to the severity of corpus but not of antral gastritis. Serum PgC and gastrin correlated to the severity of corpus gastritis only if atrophy is comprised in the classification. In contrast, serum PgA correlates only with the activity of corpus gastritis. Thus, serological parameters reflect specific histologic features of gastritis of the gastric body, but not of the antrum.
    Type of Medium: Electronic Resource
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