Imaging of Hepatocellular Carcinoma by Computed Tomography and Magnetic Resonance Imaging: State of the Art

Hepatocellular carcinoma (HCC) is a very frequent tumor worldwide. Its incidence is linked to the distribution of liver cirrhosis and viral hepatitis, which are the main risk factors for the development of HCC. For the evaluation of the cirrhotic liver and for the diagnosis of HCC, multidetector computed tomography (MDCT) proved to be a robust and reliable tool. In MDCT the diagnosis of HCC can be made based on neovascularization with increased arterial and decreased portal venous supply. With modern magnetic resonance imaging (MRI), spatial resolution and robustness increased dramatically. Beside the evaluation of neovascularization by means of gadolinium-enhanced early dynamic MRI, the main advantages of MRI are additional information on tissue composition and liver-specific function. With diffusion-weighted imaging or plain T(1)- and T(2)-weighted sequences, different tissue elements like fat, hemorrhage, glycogen, edema and cellular density can be evaluated. Liver-specific contrast agents give insight into the Kupffer cell density or the hepatocellular function. The integration of all these parts into the MR examination allows for a very high detection rate for overt HCC nowadays, although very small HCCs are still a challenge. Moreover, insight into the different stages of hepatocarcinogenesis can be possible with MRI. Despite its limited availability in some countries, it has to be rendered to be the modality of choice for the distinct evaluation of the cirrhotic liver. Copyright (C) 2009 S. Karger AG, Base

The role of visual and mechanosensory cues in structuring forward flight in Drosophila melanogaster

It has long been known that many flying insects use visual cues to orient with respect to the wind and to control their groundspeed in the face of varying wind conditions. Much less explored has been the role of mechanosensory cues in orienting insects relative to the ambient air. Here we show that Drosophila melanogaster, magnetically tethered so as to be able to rotate about their yaw axis, are able to detect and orient into a wind, as would be experienced during forward flight. Further, this behavior is velocity dependent and is likely subserved, at least in part, by the Johnston's organs, chordotonal organs in the antennae also involved in near-field sound detection. These wind-mediated responses may help to explain how flies are able to fly forward despite visual responses that might otherwise inhibit this behavior. Expanding visual stimuli, such as are encountered during forward flight, are the most potent aversive visual cues known for D. melanogaster flying in a tethered paradigm. Accordingly, tethered flies strongly orient towards a focus of contraction, a problematic situation for any animal attempting to fly forward. We show in this study that wind stimuli, transduced via mechanosensory means, can compensate for the aversion to visual expansion and thus may help to explain how these animals are indeed able to maintain forward flight

Feature link propagation across variability representations with Isabelle/HOL

When dealing with highly complex product lines it is usually indispensable to somehow subdivide the overall product line into several smaller, subordinate product lines and to define orthogonal views on the line’s variability tailored to partic- ular purposes, such as end-customer configuration. In this article we report on an ongoing research effort for dealing with feature links, i.e. logical constraints between features, in such a setting, by propagating such logical constraints defined in lower-level product lines to a higher level or from one view to another

AstroGrid-D: Enhancing Astronomic Science with Grid Technology

We present AstroGrid-D, a project bringing together astronomers and experts in Grid technology to enhance astronomic science in many aspects. First, by sharing currently dispersed resources, scientists can calculate their models in more detail. Second, by developing new mechanisms to efficiently access and process existing datasets, scientific problems can be investigated that were until now impossible to solve. Third, by adopting Grid technology large instruments such as robotic telescopes and complex scientific workflows from data aquisition to analysis can be managed in an integrated manner. In this paper, we present prominent astronomic use cases, discuss requirements on a Grid middleware and present our approach to extend/augment existing middleware to facilitate the improvements mentioned above