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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 234 (1987), S. 328-333 
    ISSN: 1432-1459
    Keywords: Oestrogen receptor ; Progesterone receptor ; Androgen receptor ; Monoclonal antibody ; Meningioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Oestrogen receptor (ER) analysis was performed in 70 meningiomas with an enzyme immunoassay, using monoclonal antibodies against human oestrogen receptor protein (oestrophilin) and with a sensitive radioligand binding assay, using 125I-oestradiol as radioligand. Low levels of ER immunoreactivity were found in tumours from 51% of patients, whereas ER binding activity was demonstrated in 40% of the meningiomas examined. In 8 (11%) tissue samples multiple binding sites for oestradiol were observed. The immunoreactive binding sites corresponded to the classical, high-affinity ER. In ligand binding studies, however, measurement of classical ER was considerably influenced by a second low-affinity, high-capacity oestrogen binding component even at low ligand concentrations. 3H-methylpromegestone and 3H-methyltrienolone, a synthetic gestagen and androgen, were used for concurrent determination of the progesterone receptor (PR) and androgen receptor (AR) binding activity. High concentrations of PR were detected in 53 (76%), whereas moderate levels of AR binding sites were demonstrated in 33 (47%) tumours. A positive correlation between ER immunoreactivity and AR binding activity is indicative for an oestrogen regulation of AR via the ER system. The presence of gonadal steroid receptors in a large proportion of meningiomas and the tendency for a dependence of receptor concentrations on the histological subtype could have implications for tumour therapy.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-9540
    Keywords: beam cooling ; slow muon production ; accelerators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Frictional cooling — that is cooling a beam of very low-energetic charged particles by moderation in matter and simultaneous acceleration in an electrostatic field — has been shown to be feasible during our experiments in 1994/1995 at PSI. In agreement with our previous closed-form and Monte Carlo calculations we found a significant increase in spectral density and a decrease in the angular spread in the case of a beam of negative muons.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-9540
    Keywords: beam cooling ; slow muon production ; accelerators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The classical methods used in beam cooling are hard to be adapted for a beam of short-lived elementary particles. A novel method, the so-called frictional cooling – that is cooling a beam of low-energy charged particles by moderation in matter and acceleration in an electrostatic field – has been shown to be feasible. In our experiments performed in 1994/1995 a beam of short-lived particles was cooled for the first time ever. Utilizing frictional cooling on a beam of slow negative muons we observed increase in phase space density by about one order of magnitude.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9540
    Keywords: proton ; proton radius ; muon ; muonic hydrogen ; Lamb shift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The contribution of the root mean square (RMS) proton charge radius to the Lamb shift (2S–2P energy difference) in muonic hydrogen (μp) amounts to 2%. Apart from the uncertainty on this charge radius, theory predicts the Lamb shift with a precision on the ppm level. We are going to measure ΔE (2 S1/2(F=1)–2 P3/2(F=2)) in a laser resonance experiment to a precision of 30 ppm (i.e., 10% of the natural linewidth) and to deduce the RMS proton charge radius with 10−3 relative accuracy, 20 times more precise than presently known. The most important requirement for the feasibility of such an experiment, namely the availability of a sufficient amount of long lived metastable μp atoms in the 2S state, has been investigated in a recent experiment at PSI. Our analysis shows that in the order of one percent of all muons stopped in low pressure hydrogen gas form a long lived μp(2S) with a lifetime of the order of 1 μs. The technical realization of our experiment involves a new high intensity low energy muon beam, an efficient low energy muon entrance detector, a randomly triggered 3 stage laser system providing the 0.5 mJ, 7 ns laser pulses at 6.02 μm wavelength, and a combination of a xenon gas proportional scintillation chamber (GPSC) and a microstrip gas chamber (MSGC) with a CsI coated surface to detect the 2 keV X rays from theμp(2P → 1S) transition.
    Type of Medium: Electronic Resource
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