Background Simulations of the Wide Field Imager of the ATHENA X-Ray Observatory

The ATHENA X-ray Observatory-IXO is a planned multinational orbiting X-ray observatory with a focal length of 11.5m. ATHENA aims to perform pointed observations in an energy range from 0.1 keV to 15 keV with high sensitivity. For high spatial and timing resolution imaging and spectroscopic observations the 640x640 pixel^2 large DePFET-technology based Wide field Imager (WFI) focal plane detector, providing a field of view of 18 arcsec will be the main detector. Based on the actual mechanics, thermal and shielding design we present estimates for the WFI cosmic ray induced background obtained by the use of Monte-Carlo simulations and possible background reduction measures.Comment: IEEE NSS MIC Conference 2011, Valencia, Spai

Resonant Biaxial Nanoprobe Utilized for Non-Contact Surface Measurements

In this work a non-contact biaxial nanoprobe for surface profile scans of macroscopic objects with 150 nm accuracy is presented. The biaxial nanoprobe oscillates in two directions to overcome the challenges of sticking in contact mode. Two electrostatic actuators drive the nanoprobe while two electrostatic sensors measure the position of the tip ball. The contact behavior between the tip ball and the specimen is determined by the contact stiffness and the contact damping. Dependent on the dominating effect the nanoprobeoperatesat semi- or non-contact mode, respectively. The aims of this paper are the investigation of the contact behavior, the proof of the independent evaluation of the two axes and the check if sticking is safely avoided

Zur Überwinterung von Flughafer (Avena fatua L.)

In einem Freiland-Modellversuch auf Tschernosem (Standort Halle, Heide-Süd) wurde in 2010/11 das Überwinterungsverhalten (Temperaturminimum Luft -17 °C, Boden in 5 cm - 5 °C) von sechs Avena fatua-Varietäten, vier vorwinterlichen Entwicklungsstadien (BBCH) und fünf standörtlich verschiedenen Herkünften untersucht.Der morphologische Entwicklungsstand der Flughaferpflanzen vor dem Winter wirkte sich dabei wesentlich auf die Frostverträglichkeit aus. Die größten Überlebensraten traten im BBCH-Stadium 20-22 auf. Jüngere (BBCH 9-10, 11) und ältere Pflanzen (BBCH 23-25) überlebten den Winter unter den spezifischen Versuchsbedingungen zumeist nicht. Bei der Varietät intermedia war die Frostverträglichkeit am größten, die geringste kam bei den Varietäten cinerea und pilosa vor. Die Varietäten pilosissima, superba und glabrata nahmen eine Mittelstellung ein.Auswirkungen waren auch bei der Herkunft der Karyopsen zu erkennen. Bei den Wische-Herkünften war die Anzahl der überwinterten Pflanzen (Varietäten cinerea und pilosissima) vergleichsweise hoch. Dabei wies die Varietät pilosissima bei den Herkünften der Wische, Elbaue und aus Thüringen deutlich größere Überwinterungsraten als die Varietät cinerea auf. Die mediterran verbreitete Wildhaferart Avena sterilis L. ssp. ludoviciana Dur. zeichnete sich gegenüber den Avena fatua-Varietäten in den BBCH-Stadien 11, 20-22 und 23-25 durch eine wesentlich größere Frosttoleranz aus.Insgesamt deuten die Ergebnisse darauf hin, dass künftig mit einer vermehrten Reproduktion frostverträglicher Flughafer-Biotypen zu rechnen sein wird. Stichwörter: Avena-Arten, Avena fatua-Varietäten, Frosttoleranz, Herkunft, Karyopse, Ontogenese, Polymorphismus, StandortOverwinter survival of wild oat (Avena fatua L.)The overwinter survival of six different varieties sampled at five geographical locations of Avena fatua L. was investigated in a model experiment on a black earth soil (site Halle, Germany). Temperatures dropped to -17 °C and –5 °C in 5 cm depth. The plants were assessed at four sampling dates before winter.The overwinter survival of wild oat was mainly affected by the developmental stage of the plants before winter. Highest survival rates were recorded in BBCH stage 20 to 22. Smaller plants (BBCH 9 to 10 or 11) did mostly not survive. The winter hardiness of the variety intermedia was higher compared with the varieties pilosissima, superba and glabrata. The lowest hardiness was recorded in the varieties cinerea and pilosa. Additionally, the sampling location had an effect on the winter hardiness of the caryopsis. If the samplings were taken in the area of the Wische, the number of surviving plants of the varieties cinerea and pilosissima was higher. Especially the variety pilossisima showed very high survival rates if sampled in the Wische, Elbaue or Thuringia compared with the variety cinerea. The wild oat species Avena sterilis L. ssp. ludoviciana Dur., which is mainly found in Mediterranean environments, showed a much stronger winter hardiness compared with the Avena fatua varietes in the growth stages 11, 20 to 22 and 23 to 25. We therefore argue that in future climatic condition it is very likely, that the reproduction of winter hard varieties will increase.Keywords: Avena-species, Avena fatua varieties, caryopsis, frost tolerance, habitat, ontogenesis, polymorphism, regional origi

NCO-sP(EO-stat-PO) Coatings on Gold Sensors—a QCM Study of Hemocompatibility

The reliability of implantable blood sensors is often hampered by unspecific adsorption of plasma proteins and blood cells. This not only leads to a loss of sensor signal over time, but can also result in undesired host vs. graft reactions. Within this study we evaluated the hemocompatibility of isocyanate conjugated star shaped polytheylene oxide—polypropylene oxide co-polymers NCO-sP(EO-stat-PO) when applied to gold surfaces as an auspicious coating material for gold sputtered blood contacting sensors. Quartz crystal microbalance (QCM) sensors were coated with ultrathin NCO-sP(EO-stat-PO) films and compared with uncoated gold sensors. Protein resistance was assessed by QCM measurements with fibrinogen solution and platelet poor plasma (PPP), followed by quantification of fibrinogen adsorption. Hemocompatibility was tested by incubation with human platelet rich plasma (PRP). Thrombin antithrombin-III complex (TAT), β-thromboglobulin (β-TG) and platelet factor 4 (PF4) were used as coagulation activation markers. Furthermore, scanning electron microscopy (SEM) was used to visualize platelet adhesion to the sensor surfaces. Compared to uncoated gold sensors, NCO-sP(EO-stat-PO) coated sensors revealed significant better resistance against protein adsorption, lower TAT generation and a lower amount of adherent platelets. Moreover, coating with ultrathin NCO-sP(EO-stat-PO) films creates a cell resistant hemocompatible surface on gold that increases the chance of prolonged sensor functionality and can easily be modified with specific receptor molecules