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  • 1995-1999  (4)
  • 1985-1989  (3)
  • 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: In a group of 335 patients with primary breast carcinoma the presence of immunoreactive carcinoembryonic antigen (CEA) and the binding of the lectin peanut agglutinin (PNA) in the primary carcinoma and in axillary lymph node metastases were investigated. The correlation between these results and a variety of established clinical, histopathologic, morphometric and biochemical prognosticators was studied. These features included lymph node status, tumour diameter, tumour type, nuclear grade, histologic grade, oestrogen receptor status, mitotic activity index and a number of nuclear measurements. The results indicate that CEA immunoreactivity of and PNA binding to tumour cells in primary breast carcinomas or lymph node metastases do not correlate with established prognostic factors in breast cancer.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1437-160X
    Keywords: Rheumatoid factors ; ELISA ; Vasculitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the occurrence of rheumatoid factors (RF) in relation to the activity of rheumatoid arthritis and the occurrence of vasculitis, RF of IgM, IgA, and IgG classes were measured in sera from 35 patients with definite or classic rheumatoid arthritis (RA) using ELISA. For 26 patients, the RF levels were studied longitudinally and compared with changes in the articular index. Although IgM RF was occasionally found in patients without RA, IgA and/or IgG RF were almost exclusively associated with RA. The titers of IgM, IgA, and IgG RF were significantly higher in sera from patients with clinically diagnosed rheumatoid vasculitis than in sera from patients without vasculitis. No significant correlation between changes in the articular index and changes in titer of any class-specific RF could be found for the group of RA patients as a whole. However, in individual patients, increases or decreases in IgM and IgG RF titer were significantly correlated with an increase or decrease in the articular index.
    Type of Medium: Electronic Resource
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  • 5
    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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  • 6
    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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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical microbiology & infectious diseases 7 (1988), S. 388-393 
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An ELISA for detection of IgG, IgA, and IgM antibody using an acid-glycine extract fromCampylobacter jejuni as antigen was developed. To determine the value of this assay for the diagnosis of acuteCampylobacter jejuni infections, the IgG, IgA, and IgM immune response againstCampylobacter jejuni was investigated at various timepoints after infection in patients with culture-proven infection. A total of 112 sera from 46 patients and 78 sera from a control group were tested. All but one of the 46 patients with culture-provenCampylobacter jejuni enteritis developed IgG antibodies againstCampylobacter jejuni. IgA and IgM ELISA both showed 97% specificity, and sensitivity of 63% and 30% respectively. IgG antibody titers generally remained at a constant level for more than 50 days, whereas IgA and IgM antibody titers declined more rapidly to normal values within 30 to 50 days after onset of clinical symptoms. Detection ofCampylobacter jejuni specific IgA antibodies in a single serum sample provided the most useful assay for serological diagnosis ofCampylobacter jejuni enteritis. The presence ofCampylobacter jejuni specific IgM antibodies was the sole diagnostic criterion in three cases. Serological diagnosis ofCampylobacter jejuni enteritis should therefore include both IgA and IgM antibody determination.
    Type of Medium: Electronic Resource
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