No abstract

Objectives: To compare the perfusion characteristics of mediastinal lymph node metastases with those of non-metastatic nodes in patients with newly diagnosed lung cancer using volume perfusion computed tomography (VPCT). Materials and methods: Between January 2010 and October 2011, 101 patients with histologically confirmed, untreated lung cancer received a 40-s VPCT of the tumor bulk; 32/101 patients had evident hilar/mediastinal metastatic disease and 17/101 patients had proven non-metastasized lymph nodes within the VPCT scan range. Validation or exclusion of metastatic node involvement was proven by mediastinoscopy, biopsy, positron emission tomography imaging and/or unequivocal volume dynamics on follow-up computed tomography. A total of 45 metastases and 23 non-metastatic lymph nodes were found within the scan range and subsequently evaluated. Blood flow (BF), blood volume (BV) and Ktrans were determined. Tumor volume was recorded as whole tumor volume. Results: In a comparison between metastatic and non-metastatic lymph nodes, we controlled for age, lymph node volume, lung tumor volume, lung tumor location, and histologic type effects and found no significant differences with respect to BF, BV, Ktrans or heterogeneity in nodal perfusion (P > 0.05, respectively), even after adjusting lymph node perfusion values to the perfusion parameters of the primary tumor (P > 0.05, respectively). Metastatic lymph node volume had a significant increasing effect on perfusion heterogeneity (P < 0.05, respectively) and BV in the primary was a highly significant factor for BV in metastatic disease (P < 0.001). Conclusion: Perfusion characteristics of mediastinal metastatic and non-metastatic lymph nodes in untreated lung cancer show considerable overlap, so that a reliable differentiation via VPCT is not possible.

A study of permanent magnet synchronous generator, constructed as a ring-generator, is presented in this paper. With this approach a milestone in reducing weight of wind turbines in high power applications like 10 MW generators can be reached. As proof-of-concept a scaled generator with a rated power of 200 kVA will be realized in a test bench. A distributed control and an active damping of axial mechanical vibrations approach is done. In order to achieve axial damping, the generator is divided in several electrical segments

This paper presents the design and control structure of a synchronous generator in ring form. The analysed generator is designed in order to test the control structure of a light-weight 10 MW generator for wind turbines. A segmented stator structure with distributed control allows control of the current of single stator segments which facilitates damping of axial displacement due to varying wind speeds by controlling axial forces. The layout process of the generator, its distributed control and the damping control are presented in this paper

No abstract