Proof of Concept: Measuring Aortic Annulus Resistance by Means of Pressure-Volume Curves During Balloon Inflation to Guide Transcatheter Aortic Valve Implantation

This study assessed the basic working principle to measure aortic annulus resistance during balloon inflation for transcatheter aortic valve implantation (TAVI), by acquisition of pressure-volume curve for a guided semi-automatic implantation. A modular bench-system was used which allows the incremental inflation of valvuloplasty balloons by means of a stepper-motor driven linear axis with simultaneous recording of the pressure changes inside the system. Different porcine aortic xenografts were assessed by use of a non-compliant valvuloplasty balloon. In a second step transcatheter aortic stents were implanted inside target sized xenografts. The recorded pressure volume-curves showed that the system can accurately differentiate between different xenografts and assess the quality of the tissue rendering real-time analysis of pressure-volume curves during balloon-inflation possible, which has the potential to optimize the implantation procedure by direct adaptation to the patient specific anatomy and characteristics. Further investigations and development are warranted

Revival of an abandoned telescope: the Boller and Chivens Bochum 0.61-metre telescope of Universidad de Valparaiso

In 2015 the Institute of Physics and Astronomy of the Universidad de Valpara\'iso in Chile received as a donation the Bochum 0.61-meter telescope. Here we preset the ongoing project to convert this senior member of La Silla Observatory to modern standards aiming at performing state-of-art science, as well as teaching and outreach. Firstly, the site characterization was performed in order to verify the observing conditions. The preliminary results were auspicious in relation to the nights available for observation. In early 2016 began the transfer work form La Silla Observatory to the new site of operations. The actual status of the telescope was analyzed and an upgrade plan was proposed to make it usable remotely using a web-based telescope control system developed in Chile by ObsTech SpA. Future upgrade and scientific collaboration will be discussed based on the site characterization and technical studies regarding the potential for new instrumentation.Comment: 8 pages, SPIE Proceedings Volume 10700, Ground-based and Airborne Telescopes VII; 107002X (2018). Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United State

How many suns are in the sky? A SPHERE multiplicity survey of exoplanet host stars I -- Four new close stellar companions including a white dwarf

We are studying the influence of stellar multiplicity on exoplanet systems, in particular systems that have been detected via radial-velocity searches. We are in particular interested in the closest companions as they would have a strong influence on the evolution of the original planet forming disks. In this study we present new companions detected during our ongoing survey of exoplanet hosts with VLT/SPHERE. We are using the extreme adaptive optics imager SPHERE at the ESO/VLT to search for faint (sub)stellar companions. We utilized the classical coronagraphic imaging mode to perform a snapshot survey (3-6 min integration time) of exoplanet host stars in the Ks-band. We detected new stellar companions to the exoplanet host stars HD1666, HIP68468, HIP107773, and HD109271. With an angular separation of only 0.38" (40 au of projected separation) HIP107773 is among the closest companions found to exoplanet host stars. The presence of the stellar companion explains the linear radial-velocity trend seen in the system. At such a small separation the companion likely had significant influence on the evolution of the planet forming disk around the primary star. We find that the companion in the HD1666 system may well be responsible for the high orbit eccentricity (0.63) of the detected Jupiter class planet, making this system one of only a few where such a connection can be established. A cross-match with the Gaia DR2 catalog showed furthermore that the near infrared faint companion around HD109271 had been detected in the optical and is significantly brighter than in the near infrared making it a white dwarf companion.Comment: 8 pages, 4 figures, accepted for publication by A&