Generation of inducible Cre systems for conditional gene inactivation in mice

Inducible gene targeting based on the Cre/loxP system is a novel technique allowing conditional gene modification in mice. Precondition of this method is the regulation of Cre activity by inducible genetic switches. This study aimed at improving inducible systems for the regulation of Cre activity at both the transcriptional and the posttranslational level, which should be tested first in vitro and subsequently in newly generated transgenic mice. In order to detect Cre activity, a special double indicator consisting of DsRed and eGFP was constructed and targeted into the ROSA26 locus of HM-1 ES cells. This indicator should constitutively express the DsRed gene flanked by loxP sites. Cre-mediated recombination excises the DsRed gene and turns on the eGFP gene, as evidenced by a change in fluorescence from red to green. Though the double indicator worked properly in transiently transfected fibroblasts, the targeting strategy used for the integration of the indicator into the ROSA26 locus presumably disrupted a putative stem loop motif of the 5'UTR resulting in a silencing of the indicator at the protein level. However, the ES cell line with the integrated double indicator is suited for targetings of inducible Cre constructs into the HPRT locus, since inducibilities are detectable by Southern Blot analysis. The Cre*PR system was one inducible system I have established. In contrast to the classical CrePR1 system, the background activity of Cre*PR was almost abolished by introducing a point mutation into the 3'end of the Cre part, thus preventing aberrant splicing of the Cre*PR encoding mRNA. Also, the PR-LBD of the Cre*PR system was improved, compared to the CrePR1, to obtain a higher affinity towards the inducer RU486. The Cre*PR system, driven by either the EF1£\ promoter or the CAGGS promoter, was then targeted into the HPRT locus. The CAGGS Cre*PR worked in ES cells as expected. These targeted ES cells were subsequently used to generate transgenic mice. In these mice, high protein levels of Cre*PR have to be obtained in order to achieve inducible Cre-mediated excision of loxP-flanked gene segments. In addition, I generated a novel B cell specific Cre*PR mouse strain by targeting Cre*PR into the mCD19 locus. In another approach to inducibly regulate Cre, a tet-on system was established consisting of the rtTA-M2 transactivator and the tetresponsive Cre cassette, which was targeted into the HPRT locus of the double indicator ES cell line. This system revealed a tight regulation of Cre expression in a doxycycline dependent manner

Strukturuntersuchungen an lasermodifizierten Kristallbereichen in Quarz

In der vorliegenden Arbeit wurden mittels Femtosekunden-Laser modifizierte Kristalle untersucht. Ziel war, den Mechanismus der Wellenleitung zu klären. Hierzu wurden hochauflösende Röntgentopographie und hochauflösende Röntgendiffraktometrie kombiniert. Mittels Finite-Elemente-Simulation wurde das Deformationsfeld und hieraus die Verteilung der lokalen Brechungsindizes bestimmt. Der Mechanismus der Wellenleitung in lasermodifizierten Quarzkristallen konnte in der vorliegenden Arbeit geklärt werden. Es handelt sich um eine Verdichtung des umgebenden Materials um einen expandierten Kern, die mittels des elastooptischen Effektes die Brechzahlmodifikationen erzeugt

Regional actorness and interregional relations : ASEAN, the EU and Mercosur

The European Union (EU) has a long tradition of interregional dialogue mechanisms with other regional organisations and is using these relations to project its own model of institutionalised actorness. This is partly motivated by the emerging actorness of the EU itself, which benefits from fostering capable regional counterparts in other parts of the world. This article advances the argument that actorness, which we conceptualise in terms of institutions, recognition and identity, is a relational concept, dependent on context and perception. Taking the Association of Southeast Asian Nations (ASEAN) and the Common Market of the South (Mercosur) and their relations with the EU as case studies, this article demonstrates that the actorness capabilities of all three organisations have been enhanced as result of ASEAN-EU and Mercosur-EU relations. However, there are clear limits to the development of the three components of regional actorness and to the interregional relations themselves. While there is evidence of institutional enhancement in ASEAN and Mercosur, these formal changes have been grafted on top of firmly entrenched normative underpinnings. The formation of different identities and institutional capacities has narrowed the scope of EU interregionalism despite the initial success of improved regional actorness.Deutscher Akademischer Austauschdiensthttp://www.tandfonline.com/loi/geui202018-12-02hj2018Political Science

Parametrisierte Speicherzellen zur Unterstützung des Selbsttests mit optimierten und konventionellen Zufallsmustern

Viele Selbsttestverfahren für hochintegrierte Schaltungen beruhen auf der Erzeugung von Zufallsmustem mit rückgekoppelten Schieberegistem. Oft wird jedoch für eine ausreichende Fehlererfassung eine unwirtschaftlich große Menge von Zufallsmustern benötigt, falls diese gleichverteilt erzeugt werden. Mit ungleichverteilten Zufallsmustern kann die Testlänge entscheidend reduziert werden, ein entsprechendes Selbsttestkonzept wurde als GURT (Generator of Unequiprobable Random Tests) vorgeschlagen. Im vorliegenden Beitrag werden Grundzellen zur Synthese von Registern nach dem GURT-Prinzip vorgestellt und die Probleme beim Entwurf eines entsprechenden Syntheseprogrammes diskutiert. Anhand eines Beispiels werden die Selbsttestkonzepte nach dem GURT- und nach dem BILBO-Prinzip verglichen

On Goodput and Energy Measurements of Network Coding Schemes in the Raspberry Pi

Given that next generation networks are expected to be populated by a large number of devices, there is a need for quick deployment and evaluation of alternative mechanisms to cope with the possible generated traffic in large-scale distributed data networks. In this sense, the Raspberry Pi has been a popular network node choice due to its reduced size, processing capabilities, low cost and its support by widely-used operating systems. For information transport, network coding is a new paradigm for fast and reliable data processing in networking and storage systems, which overcomes various limitations of state-of-the-art routing techniques. Therefore, in this work, we provide an in-depth performance evaluation of Random Linear Network Coding (RLNC)-based schemes for the Raspberry Pi Models 1 and 2, by showing the processing speed of the encoding and decoding operations and the corresponding energy consumption. Our results show that, in several scenarios, processing speeds of more than 80 Mbps in the Raspberry Pi Model 1 and 800 Mbps in the Raspberry Pi Model 2 are attainable. Moreover, we show that the processing energy per bit for network coding is below 1 nJ or even an order of magnitude less in these scenarios

Caudate Nucleus and Insular Activation During a Pain Suppression Paradigm Comparing Thermal and Electrical Stimulation

Pain modulation is an integral function of the nervous system. It is needed to adapt to chronic stimuli. To gain insights into pain suppression mechanisms, two studies concerning the suppression of the feeling of pain with different stimulation modalities (heat vs. electrical stimuli) but using the same stimulation paradigms were compared: 15 subjects each had been stimulated on both hands under the instruction to suppress the feeling of pain