Nuclear recoil measurements in Superheated Superconducting Granule detectors

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70Me$\!$V neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few ke$\!$V. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15-20$\mu$m in diameter will be discussed. For the first time, recoil energy thresholds of $\sim$1ke$\!$V have been measured.Comment: 7pages in Latex format, Preprint Bu-He 93/6 (University of Berne, Switzerland), four figures available upon request via [email protected] or [email protected]

Correlation of SHOX2 Gene Amplification and DNA Methylation in Lung Cancer Tumors

<p>Abstract</p> <p>Background</p> <p>DNA methylation in the <it>SHOX2 </it>locus was previously used to reliably detect lung cancer in a group of critical controls, including 'cytologically negative' samples with no visible tumor cell content, at a high specificity based on the analysis of bronchial lavage samples. This study aimed to investigate, if the methylation correlates with <it>SHOX2 </it>gene expression and/or copy number alterations. An amplification of the <it>SHOX2 </it>gene locus together with the observed tumor-specific hypermethylation might explain the good performance of this marker in bronchial lavage samples.</p> <p>Methods</p> <p><it>SHOX2 </it>expression, gene copy number and DNA methylation were determined in lung tumor tissues and matched morphologically normal adjacent tissues (NAT) from 55 lung cancer patients. Quantitative HeavyMethyl (HM) real-time PCR was used to detect <it>SHOX2 </it>DNA methylation levels. <it>SHOX2 </it>expression was assayed with quantitative real-time PCR, and copy numbers alterations were measured with conventional real-time PCR and array CGH.</p> <p>Results</p> <p>A hypermethylation of the <it>SHOX2 </it>locus in tumor tissue as compared to the matched NAT from the same patient was detected in 96% of tumors from a group of 55 lung cancer patients. This correlated highly significantly with the frequent occurrence of copy number amplification (p < 0.0001), while the expression of the <it>SHOX2 </it>gene showed no difference.</p> <p>Conclusions</p> <p>Frequent gene amplification correlated with hypermethylation of the <it>SHOX2 </it>gene locus. This concerted effect qualifies <it>SHOX2 </it>DNA methylation as a biomarker for lung cancer diagnosis, especially when sensitive detection is needed, i.e. in bronchial lavage or blood samples.</p

Fabrication of Pt/Ru Nanoparticle Pair Arrays with Controlled Separation and their Electrocatalytic Properties

Aiming at the investigation of spillover and transport effects in electrocatalytic reactions on bimetallic catalyst electrodes, we have prepared novel, nanostructured electrodes consisting of arrays of homogeneously distributed pairs of Pt and Ru nanodisks of uniform size and with controlled separation on planar glassy carbon substrates. The nanodisk arrays (disk diameter approximate to 60 nm) were fabricated by hole-mask colloidal lithography; the separation between pairs of Pt and Ru disks was varied from -25 nm (overlapping) via +25 nm to +50 nm. Morphology and (surface) composition of the Pt/Ru nanodisk arrays Were characterized by scanning electron microscopy, energy dispersive X-ray analysis, and X-ray Photoelectron spectroscopy, the electrochemical/electrocatalytic properties were explored by cyclic voltammetry, COad monolayer oxidation ("COad stripping"), and potentiodynamic hydrogen oxidation. Detailed analysis of the 2 COad oxidation peaks revealed that on all bimetallic pairs these cannot be reproduced by superposition of the peaks obtained on electrodes with Pt/Pt or Ru/Ru pairs, pointing to effective Pt-Ru interactions even between rather distant pairs (50 nm). Possible reasons for this observation and its relevance for the understanding of previous reports of highly active catalysts with separate Pt and Ru nanoparticles are discussed. The results clearly demonstrate that this preparation method is perfectly suited for fabrication of planar model electrodes with well-defined arrays of bimetallic nanodisk pairs, which opens up new possibilities for model studies of electrochemical/electrocatalytic reactions

Measurement of electroweak parameters from hadronic and leptonic decays of the Z 0

We have studied the reactions e + e − →hadrons, e + e − , μ + μ − and τ + τ − , in the energy range 88.2 GeV. A total luminosity of 5.5 pb −1 , corresponding to approximately 115000 hadronic and 10000 leptonic Z 0 decays, has been recorded with the L3 detector. From a simultaneous fit to all of our measured cross section data, we obtain assuming lepton universality:Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47890/1/10052_2005_Article_BF01475788.pd

Einfluss etablierter Wachstumsfaktoren auf Proliferation und Apoptose von primären humanen Osteoblastenzellkulturen

Einleitung: Tissue Engineering von Knochen gilt bei der funtkionell-ästhetischen Rekonstruktion ossärer Defekte als vielversprechende Alternative zum autologen Gewebsersatz. Das Regenerationspotential von Osteoblasten wird durch Wachstumsfaktoren beeinflusst. Neben dem Proliferationsverhalten stellt auch die Beurteilung des apoptotischen Ausmaßes bei der Etablierung intakter Zellkulturen eine wichtige Voraussetzung für das klinisch orientierte Tissue Engineering in der rekonstruktiven Kopf-Hals-Chirurgie dar. Material und Methoden: Primäre Zellkulturen von humanen Osteoblasten (hOB) wurden mit IGF-1, -2 und TNFalpha angesetzt. Durch immunhistochemische Färbung gegen Osteokalzin wurde der Reinheitsgrad verifiziert. Eine Proliferationsanalyse erfolgte mittels alamarBlue(TM)-Assay nach 1, 5, 10 und 15 Tagen. Die Apoptoseanalyse fand immunhistochemisch (Labelled-Streptavidin-Biotin-Methode) gegen die Regulator-Proteine BAX und BCL-2, den Death Receptor Fas sowie die zentrale Apoptose-Protease Caspase3 statt. Ergebnisse: Es bildeten sich lückenhafte Zellrasen in Monolayer mit typischer polygonaler Zellform. Das Proliferationsverhalten wies keine signifikanten Unterschiede zwischen den verschiedenen Wachstumsfaktoren in unterschiedlichen Konzentrationen nach Herstellerempfehlungen auf. Im zeitlichen Verlauf konnte eine Veränderung der BCL-2/BAX-Ratio zugunsten des proapoptotischen Regulator-Proteins BAX und eine Zunahme der Caspase 3-Expression beobachtet werden. Schlussfolgerung: Der Einsatz dieser Wachstumsfaktoren nach den Herstellerangaben zeigte keinen Einfluss auf Proliferation und Apoptose. Gemäß dem Kosten-Nutzen-Effekt liegen Untersuchungen mit erhöhten Konzentrationen außerhalb des Interessenfeldes, so dass sich diese Faktoren zum Einsatz an hOB nicht zu eignen scheinen