Wnt/beta-catenin/Tcf signaling: A critical pathway in gastrointestinal tumorigenesis

Cancers of the gastrointestinal tract, including the liver, bile ducts, and pancreas, constitute the largest group of malignant tumors. Colorectal cancer is one of the most common neoplastic diseases in Western countries and one of the leading causes of cancer-related deaths. Inactivation of the adenomatous polyposis coli (APC) tumor-suppressor gene during early adenoma formation is thought to be the first genetic event in the process of colorectal carcinogenesis followed by mutations in oncogenes like K-Ras and tumor-suppressor genes like p53. Identification of the interaction of APC with the proto-oncogene beta-catenin has linked colorectal carcinogenesis to the Wnt-signal transduction pathway. The main function of APC is thought to be the regulation of free beta-catenin in concert with the glycogen synthase kinase 3beta (GSK-3beta) and Axin proteins. Loss of APC function, inactivation of Axin or activating beta-catenin mutations result in the cellular accumulation of beta-catenin. Upon translocation to the nucleus beta-catenin serves as an activator of T-cell factor (Tcf)-dependent transcription leading to an increased expression of several specific target genes including c-Myc, cyclin D1, MMP-7, and ITF-2. While APC mutations are almost exclusively found in colorectal cancers, deregulation of Wnt/beta-catenin/Tcf signaling is also common in other gastrointestinal and extra-gastrointestinal human cancers. In a fraction of hepatocellular carcinomas the Writ pathway is deregulated by inactivation of Axin or stabilizing mutations of beta-catenin. The majority of hepatoblastomas and a group of gastric cancers also carry beta-catenin mutations. Clearly, this pathway harbors great potential for future applications in cancer diagnostics, staging, and therapy. Copyright (C) 2002 S. Karger AG, Basel

Environmental policy and industrial competitiveness: The pollution haven hypothesis reconsidered

The Pollution-Haven Hypothesis suggests that tight environmental standards reduce domestic producers' competitiveness and give rise to their relocating to countries with more lenient standards. This paper questions that relocation is always caused by reduced competitiveness at home. By using a signaling approach, I show that relocation can be undertaken for purely strategic reasons. Relocation is the producer's tool to convince the policy maker to refrain from a further tightening of environmental control. I show that trade liberalization increases probability of strategic relocation

Coupling of a single NV-center in diamond to a fiber-based microcavity

We report on the coupling of a single Nitrogen-vacancy (NV) center in a nanodiamond to a fiber-based microcavity at room temperature. Investigating the very same NV center inside the cavity and in free-space allows to systematically explore a new regime of phonon-assisted cavity feeding. Making use of the NV center's strongly broadened emission, we realize a widely tunable, narrowband single photon source. A master equation model well reproduces our experimental results and predicts a transition into a Purcell-enhanced emission regime at low temperatures.Comment: latest version accepted for publication in Phys. Rev. Let

Droplets on liquids and their long way into equilibrium

The morphological paths towards equilibrium droplets during the late stages of the dewetting process of a liquid film from a liquid substrate is investigated experimentally and theoretically. As liquids, short chained polystyrene (PS) and polymethyl-methacrylate (PMMA) are used, which can be considered as Newontian liquids well above their glass transition temperatures. Careful imaging of the PS/air interface of the droplets during equilibration by \emph{in situ} scanning force microscopy and the PS/PMMA interface after removal of the PS droplets reveal a surprisingly deep penetration of the PS droplets into the PMMA layer. Droplets of sufficiently small volumes develop the typical lens shape and were used to extract the ratio of the PS/air and PS/PMMA surface tensions and the contact angles by comparison to theoretical exact equilibrium solutions of the liquid/liquid system. Using these results in our dynamical thin-film model we find that before the droplets reach their equilibrium they undergo several intermediate stages each with a well-defined signature in shape. Moreover, the intermediate droplet shapes are independent of the details of the initial configuration, while the time scale they are reached depend strongly on the droplet volume. This is shown by the numerical solutions of the thin-film model and demonstrated by quantitative comparison to experimental results

Impact of Agricultural Development on the Environment: Issues in the Research Collaboration with Developing Countries. The Orientation of German Agricultural Research

Statement by D.F.R. Bommer of the Arbeitsgruppe für Tropische und Subtropische Agrarforschung (ATSAF) on environmental considerations in West German agricultural policy, agricultural research, and bilateral development aid.Dr. Bommer presented the report at the CGIAR mid term meeting in May 1988

Publish or perish? The increasing importance of publications for prospective economics professors in Austria, Germany and Switzerland

Tenure decisions depend, among other factors, on a candidate�s career age and publication record. We measure publications in units of both Top 5 journals and of the European Economic Review (EER), associating publication output with journals indexed in EconLit. We find that the average age of a professor in the year of his/her first appointment is 38, i.e. approximately 8 years after completing the PhD. Between 1970 and 2006, the average publication record at the time of the first appointment is equivalent to 1.5 standardized Top 5 articles (one co-author, 20 pages) or 2.3 standardized EER articles. Publication records vary across sub fields and improve over time. We predict that someone running for a tenured job after 2011 should (average of all fields) aim at an average equivalent of 4 standardized Top 5 articles or 6 standardized EER articles

Impact of energy dissipation on interface shapes and on rates for dewetting from liquid substrates

We revisit the fundamental problem of liquid-liquid dewetting and perform a detailed comparison of theoretical predictions based on thin-film models with experimental measurements obtained by atomic force microscopy (AFM). Specifically, we consider the dewetting of a liquid polystyrene (PS) layer from a liquid polymethyl methacrylate (PMMA) layer, where the thicknesses and the viscosities of PS and PMMA layers are similar. The excellent agreement of experiment and theory reveals that dewetting rates for such systems follow no universal power law, in contrast to dewetting scenarios on solid substrates. Our new energetic approach allows to assess the physical importance of different contributions to the energy-dissipation mechanism, for which we analyze the local flow fields and the local dissipation rates.Comment: 15 pages, 5 figure

Spieglein, Spieglein an der Wand ...: Eine publikationsanalytische Erfassung der Forschungsleistungen volkswirtschaftlicher Fachbereiche in Deutschland, Österreich und der Schweiz

In diesem Aufsatz wird gezeigt, wie die Forschungsleistungen volkswirtschaftlicher Fachbereiche mit Hilfe eines publikationsanalyischen Verfahrens quantitativ abgeschätzt werden können. Das vorgestellte Verfahren erfasst alle einschlägigen Zeitschriftenartikel, die im Social Science Citation Index ausgewiesen werden und gewichtet die Publikationen insbesondere nach der Reputation der Zeitschrift, in der sie erschienen sind. Wir wenden das Verfahren auf die volkswirtschaftlichen Fachbereiche in Deutschland, Österreich und der Schweiz an und gelangen so zu einer Rangliste der Forschungsleistungen dieser Fachbereiche.This paper presents a method of assessing the research productivity of economics departments. The method is based on an evaluation of all relevant journal publications which are included in the Social Science Citalion Index. The publications are weighted especially according to the reputation of the journal in which they appeared. We apply this method to the economics departments in Germany. Austria and Switzerland to arrive at a ranking of the analyzed departments with respeet to their research productivity