1,766 research outputs found
Determination of the Her-2/neu gene amplification status in cytologic breast cancer specimens using automated silver-enhanced in-situ hybridization (SISH)
Silver-enhanced in-situ hybridization (SISH) is an emerging tool for the determination of the Her-2/neu amplification status in breast cancer. SISH is technically comparable to fluorescence in-situ hybridization (FISH) but does not require a fluorescence microscope for its interpretation. Although recent studies on histologic evaluations of SISH are promising, we aimed to evaluate its performance on 71 cytologic breast cancer specimens with the new combined Her-2/Chr17 probe. Her-2/neu status as routinely determined by FISH was available for all patients. We found SISH signals in cytologic cell blocks and smear specimens easy to evaluate in most cases. Small numbers of tumor cells and difficulties in identifying tumor cells in lymphocyte-rich backgrounds were limiting factors. Her-2/neu status, as determined by Her-2/Chr17 SISH, was basically identical to the results of the corresponding FISH. The discrepancies were mainly owing to the heterogeneity of Her-2/neu amplification in the tumor tissue. Interobserver agreement for the SISH evaluation was high (kappa value: 0.972). We conclude that Her-2/Chr17 SISH is a useful and accurate method for the evaluation of the Her-2/neu gene amplification status in cytologic breast cancer specimens, particularly in metastatic breast cancer lesions. The advantages of signal permanency and bright-field microscopic result interpretation make this technique an attractive alternative to the current FISH-based gold standard
Bestimmung der Steifigkeitsparameter von zweilagigen Litzen
In der vorliegenden Arbeit werden Ergebnisse zu analytischen, numerischen und experimentellen Steifigkeitsuntersuchungen an zweilagigen Litzen vorgestellt. BerĂŒcksichtigt werden dabei die Grundbeanspruchungsarten Zug, Torsion und Biegung. Bei den analytischen und numerischen Verfahren wird linearelastisches Materialverhalten vorausgesetzt. Die analytische Bestimmung des Litzenverhaltens erfolgte auf der Grundlage zweier aus der Literatur bekannter Methoden. Bei der numerischen Berechnung der Steifigkeitsparameter wurde auf der Basis der Methode der Finiten Elemente fĂŒr die Litzen ein einfaches Stab-Modell entwickelt. FĂŒr die Berechnung wurde das Finite-Element-Programm COSAR verwendet. Die experimentellen Untersuchungen erfolgten auf einer Hydropulsanlage. Da fĂŒr die experimentellen Untersuchungen zweilagige Litzen mit speziellen Querschnittsabmessungen vorlagen, beschrĂ€nken sich auch die numerischen Modelle auf diese Querschnitte. Eine Anwendung der Berechnungsmethoden und eine Entwicklung von Modellen auf deren Grundlage fĂŒr ein- und mehrlagige Litzen mit anderen Querschnitten ist möglich
Electrical properties of a-antimony selenide
This paper reports conduction mechanism in a-\sbse over a wide range of
temperature (238K to 338K) and frequency (5Hz to 100kHz). The d.c. conductivity
measured as a function of temperature shows semiconducting behaviour with
activation energy E= 0.42 eV. Thermally induced changes in the
electrical and dielectric properties of a-\sbse have been examined. The a.c.
conductivity in the material has been explained using modified CBH model. The
band conduction and single polaron hopping is dominant above room temperature.
However, in the lower temperature range the bipolaron hopping dominates.Comment: 9 pages (RevTeX, LaTeX2e), 9 psfigures, also at
http://pu.chd.nic.in/ftp/pub/san16 e-mail: gautam%[email protected]
Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions
Recent progress in the study of the photon emission from highly-charged heavy
ions is reviewed. These investigations show that high- ions provide a unique
tool for improving the understanding of the electron-electron and
electron-photon interaction in the presence of strong fields. Apart from the
bound-state transitions, which are accurately described in the framework of
Quantum Electrodynamics, much information has been obtained also from the
radiative capture of (quasi-) free electrons by high- ions. Many features in
the observed spectra hereby confirm the inherently relativistic behavior of
even the simplest compound quantum systems in Nature.Comment: Version 18/11/0
Purification and characterization of 4-methylmuconolactone methylisomerase, a novel enzyme of the modified 3-oxoadipate pathway in the gram-negative bacterium Alcaligenes eutrophus JMP 134
Measuring Charge Transport in an Amorphous Semiconductor Using Charge Sensing
We measure charge transport in hydrogenated amorphous silicon (a-Si:H) using
a nanometer scale silicon MOSFET as a charge sensor. This charge detection
technique makes possible the measurement of extremely large resistances. At
high temperatures, where the a-Si:H resistance is not too large, the charge
detection measurement agrees with a direct measurement of current. The device
geometry allows us to probe both the field effect and dispersive transport in
the a-Si:H using charge sensing and to extract the density of states near the
Fermi energy.Comment: 4 pages, 4 figure
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