Therapeutic options to prevent recurrence of an aggressive aneurysmatic bone cyst of the cervical spine of a 16 year old boy - a case report

The aneurysmatic bone cyst (ABC) is a benign primary bone tumour. If located in the cervical spine, its expansive growth and destructive behaviour may lead to instability and serious neurological impairment. We report a case of a 16-year-old boy with an aggressive ABC in the 7th cervical vertebra. Computertomographic and magnetic resonance imaging revealed the envelopment of the left 7th and 8th spinal nerve along with the anterior displacement of the left vertebral artery. The interdisciplinary surgical strategy consisted of a partially incomplete cyst resection, subtotal spondylectomy with posterior screw-and-rod fixation from C6-Th1, iliac crest bone grafting and anterior plating from C6-Th1. With regard to the high rate of recurrence after incomplete resection published in the recent literature, the patient was postoperatively treated by megavoltage radiotherapy with a total dose of 30Gy (daily dose of 1.8 Gy for 3 weeks). The clinical and radiographic follow-up showed complete recovery of all neurologic impairments and no signs of tumour recurrence at 3, 6 and 12 months after surgery. This case highlights diverse treatment regimens and shall outline the challenge and the problems of the interdisciplinary decision-making in adolescents presenting with ABC in high-demanding anatomical regions

Star formation efficiency in the Barred Spiral Galaxy NGC 4303

We present new $^{12}$CO(J=1-0) observations of the barred galaxy NGC 4303 using the Nobeyama 45m telescope (NRO45) and the Combined Array for Research in Millimeter-wave Astronomy (CARMA). The H$\alpha$ images of barred spiral galaxies often show active star formation in spiral arms, but less so in bars. We quantify the difference by measuring star formation rate and efficiency at a scale where local star formation is spatially resolved. Our CO map covers the central 2\farcm3 region of the galaxy; the combination of NRO45 and CARMA provides a high fidelity image, enabling accurate measurements of molecular gas surface density. We find that star formation rate and efficiency are twice as high in the spiral arms as in the bar. We discuss this difference in the context of the Kennicutt-Schimidt (KS) law, which indicates a constant star formation rate at a given gas surface density. The KS law breaks down at our native resolution ($\sim$ 250 pc), and substantial smoothing (to 500 pc) is necessary to reproduce the KS law, although with greater scatter.Comment: 17 pages, 10 figures, published by ApJ; http://adsabs.harvard.edu/abs/2010ApJ...721..383

Tidal interaction vs. ram pressure stripping effects as seen in X-rays. Hot gas in group and cluster galaxies

The hot intracluster/intragroup medium (ICM/IGM) and a high galaxy density can lead to perturbations of the galactic interstellar medium (ISM) due to ram pressure and/or tidal interaction effects. In radio polarimetry observations, both phenomena may manifest similar features. X-ray data can help to determine the real origin of the perturbation. We analyse the distribution and physical properties of the hot gas in the Virgo cluster spiral galaxies NGC 4254 and NGC 4569, which indicate that the cluster environment has had a significant influence on their properties. By performing both spatial and spectral analyses of X-ray data, we try to distinguish between two major phenomena: tidal and ram pressure interactions. We compare our findings with the case of NGC 2276, in which a shock was reported, by analysing XMM-Newton X-ray data for this galaxy. We use archival XMM-Newton observations of NGC 4254, NGC 4569, and NGC 2276. Maps of the soft diffuse emission in the energy band 0.2 - 1 keV are obtained. For the three galaxies, especially at the position of magnetic field enhancements we perform a spectral analysis to derive gas temperatures and thus to look for shock signatures. A shock is a signature of ram pressure resulting from supersonic velocities; weak tidal interactions are not expected to influence the temperature of the ionized gas. In NGC 4254, we do not observe any temperature increase. This suggests tidal interactions rather than ram pressure stripping. In NGC 4569 the radio polarized ridge shows a higher temperature, which may indicate ram-pressure effects. For NGC 2276, we do not find clear indications of a shock. The main driver of the observed distortions is most likely tidal interaction. Determining gas temperatures via sensitive X-ray observations seems to be a good method for distinguishing between ram pressure and tidal interaction effects acting upon a galaxy.Comment: 13 pages, 13 figures, 8 tables, Accepted for publication in Astronomy and Astrophysic

The magnetic fields of large Virgo cluster spirals: Paper II

The Virgo cluster of galaxies provides excellent conditions for studying interactions of galaxies with the cluster environment. Both the high-velocity tidal interactions and effects of ram pressure stripping by the intracluster gas can be investigated in detail. We extend our systematic search for possible anomalies in the magnetic field structures of Virgo cluster spirals in order to characterize a variety of effects and attribute them to different disturbing agents. Six angularly large Virgo cluster spiral galaxies (NGC4192, NGC4302, NGC4303, NGC4321, NGC4388, and NGC4535) were targets of a sensitive total power and polarization study using the 100-m radio telescope in Effelsberg at 4.85GHz and 8.35GHz (except for NGC4388 observed only at 4.85GHz, and NGC4535 observed only at 8.35GHz). Magnetic field structures distorted to various extent are found in all galaxies. Three galaxies (NGC4302, NGC4303, and NGC4321) show some signs of possible tidal interactions, while NGC4388 and NGC4535 have very likely experienced strong ram-pressure and shearing effects, respectively, visible as distortions and asymmetries of polarized intensity distributions. As in our previous study, even strongly perturbed galaxies closely follow the radio-far-infrared correlation. In NGC4303 and NGC4321, we observe symmetric spiral patterns of the magnetic field and in NGC4535 an asymmetric pattern. Magnetic fields allow us to trace even weak interactions that are difficult to detect with other observations. Our results show that the degree of distortions of a galaxy is not a simple function of the distance to the cluster center but reflects also the history of its interactions. The angle between the velocity vector and the rotation vector of a galaxy may be a general parameter that describes the level of distortions of galactic magnetic fields.Comment: 12 pages, 18 figures, 2 tables. Accepted for publication in Astronomy and Astrophysic

Hot gas in Mach cones around Virgo Cluster spiral galaxies

The detailed comparison between observations and simulations of ram pressure stripped spiral galaxies in the Virgo cluster has led to a three dimensional view of the galaxy orbits within the hot intracluster medium. The 3D velocities and Mach numbers derived from simulations can be used to derive simple Mach cone geometries for Virgo spiral galaxies. We search for indications of hot gas within Mach cones in X-ray observations of selected Virgo Cluster spiral galaxies (NGC 4569, NGC 4388, and NGC 4501). We find extraplanar diffuse X-ray emission in all galaxies. Based on the 3D velocity vectors from dynamical modelling a simple Mach cone is fitted to the triangular shape of NGC 4569's diffuse X-ray emission. Assuming that all extraplanar diffuse X-ray emission has to be located inside the Mach cone, we also fit Mach cones to NGC 4388's and NGC 4501's extraplanar X-ray emission. For NGC 4569 it is hard to reconcile the derived Mach cone opening angle with a Mach number based on the sound speed alone. Instead, a Mach number involving the Alfv\'enic speed seems to be more appropriate, yielding a magnetic field strength of $\sim 3$-6 $\mu$G for a intracluster medium density of $n \sim 10^{-4}$ cm$^{-3}$. Whereas the temperature of the hot component of NGC 4569's X-ray halo (0.5 keV) is at the high end but typical for a galactic outflow, the temperature of the hot gas tails of NGC 4388 and NGC 4501 are significantly hotter (0.7-0.9 keV). In NGC 4569 we find direct evidence for a Mach cone which is filled with hot gas from a galactic superwind. We suggest that the high gas temperatures in the X-ray tails of NGC 4388 and NGC 4501 are due to the mixing of the stripped ISM into the hot intracluster medium of the Virgo cluster.Comment: 11 pages, 10 figures, 5 tables. Accepted for publication in Astronomy and Astrophysic

Molecular gas in NUclei of GAlaxies (NUGA) VII. NGC4569, a large scale bar funnelling gas into the nuclear region

This work is part of the NUGA survey of CO emission in nearby active galaxies. We present observations of NGC4569, a member of the Virgo Cluster. We analyse the molecular gas distribution and kinematics in the central region and we investigate a possible link to the strong starburst present at the nucleus. 70% of the 1.1x10^9 Msolar of molecular gas detected in the inner 20" is found to be concentrated within the inner 800 pc and is distributed along the large scale stellar bar seen in near-infrared observations. A hole in the CO distribution coincides with the nucleus where most of the Halpha emission and blue light are emitted. The kinematics are modelled in three different ways, ranging from the purely geometrical to the most physical. This approach allows us to constrain progressively the physical properties of the galaxy and eventually to emerge with a reasonable fit to an analytical model of orbits in a barred potential. Fitting an axisymmetric model shows that the non-circular motions must be comparable in amplitude to the circular motions (120 km/s). Fitting a model based on elliptical orbits allows us to identify with confidence the single inner Lindblad resonance (ILR) of the large scale bar. Finally, a model based on analytical solutions for the gas particle orbits in a weakly barred potential constrained by the ILR radius reproduces the observations well. The mass inflow rate is then estimated and discussed based on the best fit model solution. The gravitational torques implied by this model are able to efficiently funnel the gas inside the ILR down to 300 pc, although another mechanism must take over to fuel the nuclear starburst inside 100 pc.Comment: accepted for publication in A&

CarbonSafe – Zbudowanie zintegrowanego systemu pomiarowego dla komponentów CFRP w przemyśle motoryzacyjnym

Overview of a German project funded by the Federal Department of Education and Research within the scope of the priority program “KMU Innovativ” (Funding No. 16ES0333). The idea of the project was to develop a simple, but efficient SHM system for CFRP structures based on guided waves. The key milestones of the project were: • specification of required sensors and development of sensors • sensor characterization and application • concept of external diagnostic equipment • transducer self-test • validation by generic geometries • proof by POD and simulation of measurement results • implementation of sensors into automotive structure • field test.Przegląd niemieckiego projektu finansowanego przez Federalny Departament Edukacji i Badań w ramach programu priorytetowego "KMU Innovativ" (Fundusze nr 16ES0333). Ideą projektu było opracowanie prostego, ale skutecznego systemu SHM dla struktur CFRP bazującego na zastosowaniu fal prowadzonych. Kluczowymi kamieniami milowymi tego projektu były: • specyfikacja wymagań i opracowanie czujników • określenie charakterystyki i zastosowanie czujnika • koncepcja zewnętrznego sprzętu diagnostycznego • autotest przetwornika • walidacja za pomocą ogólnych geometrii • dowód przez POD i symulacje wyników pomiarów • wdrożenie czujników do rozwiązań samochodowych • test w terenie