An Automated Coronary Artery Occlusion Device for Stimulating Collateral Development in Vivo

Introduction: Repetitive, brief coronary artery occlusions produce collateral development in experimental animals. This model causes coronary collateralization in a highly reproducible fashion, but the process is very labor intensive. We report the design and use of a fully automated hydraulic coronary occlusion device capable of producing repetitive coronary occlusions and enhancement of coronary collateral development in dogs. Methods: The device consists of analog electronics that allow adjustment of occlusion number, frequency, pressure and duration, and mechanical components responsible for the coronary occlusion. The motor and piston of the device are coupled to a chronically implanted hydraulic vascular occluder placed around the left anterior descending coronary artery (LAD) of dogs instrumented for measurement of systemic and coronary hemodynamics. One group of dogs (n=6) underwent brief (2 min) LAD occlusions once per hour, eight times per day, 5 days/week for 3 weeks to stimulate collateral development (measured using radioactive microspheres). Another group of dogs (n=6) that did not receive repetitive occlusions served as controls. Results: The device reproducibly produced repetitive LAD occlusions for the duration, frequency, and time interval initially programmed. A time-dependent increase in transmural collateral blood flow was observed in dogs undergoing repetitive occlusions using the device. Collateral blood flow was unchanged in dogs that did not undergo occlusions. Discussion: The automated occluder device reliably produces repetitive coronary occlusions and may facilitate further study of coronary collateral development in response to chronic myocardial ischemia

A Sample of Candidate Radio Stars in FIRST and SDSS

We conduct a search for radio stars by combining radio and optical data from the Faint Images of the Radio Sky at Twenty cm survey (FIRST) and the Sloan Digital Sky Survey (SDSS). The faint limit of SDSS makes possible a homogeneous search for radio emission from stars of low optical luminosity. We select a sample of 112 candidate radio stars in the magnitude range $15<i\lesssim19.1$ and with radio flux $S_{20}\geq1.25$mJy, from about 7000 deg$^2$ of sky. The selection criteria are positional coincidence within 1\arcsec, radio and optical point source morphology, and an SDSS spectrum classified as stellar. The sample contamination is estimated by random matching to be $108\pm13$, suggesting that at most a small fraction of the selected candidates are genuine radio stars. Therefore, we rule out a very rare population of extremely radio-loud stars: no more than 1.2 of every million stars in the magnitude range $15<i<19.1$ stars has radio flux $S_{20}\geq1.25$ mJy. We investigate the optical and radio colors of the sample to find candidates that show the largest likelihood of being real radio stars. The significant outliers from the stellar locus, as well as the magnetically active stars, are the best candidates for follow-up radio observations. We conclude that, while the present wide-area radio surveys are not sensitive enough to provide homogeneous samples of the extremely rare radio stars, upcoming surveys which exploit the great sensitivity of current and planned telescopes do have sufficient sensitivity and will allow the properties of this class of object to be investigated in detail.Comment: Online data available at http://www.astro.washington.edu/users/akimball/radiocat/radiostars . Accepted for publication in the Astrophysical Journal. (fixed formatting issue

Real world evidence: Perspectives from a European Society of Cardiology Cardiovascular Round Table with contribution from the European Medicines Agency

Real world data (RWD) refers to healthcare information that is routinely collected in electronic healthcare records (EHR), hospital and pharmacy records, patient and disease registries, and health insurance databases. The collection and analysis of this vast amount of data is an important complement to that obtained from conventional randomised controlled trials (RCT). Real world data has been used for healthcare quality improvements, to conduct clinical trials, to support drug and device development, and to inform medical guidelines. The utility of RWD may be facilitated by common data models, which standardise format and content, and allow data from different health systems to be analysed together. The European Society of Cardiology (ESC) supports the use of RWD in collaboration with national cardiac societies, regulatory authorities, and industry to encourage continuous quality of care improvements at the hospital and country level, to conduct registry-based randomised clinical trials (R-RCT) and to facilitate safety surveillance of novel drugs and devices. The European Medicines Agency (EMA) is developing systems and processes to enable the use of RWD that can help in trial planning, defining clinical contexts, and enhancing outcome assessments. RWD can also contribute to the measurement of the impact of regulatory actions, such as contraindications or restriction of indications by looking at medicines use patterns over time across European Member States. A number of other initiatives from the European Commission and the EMA are underway to strengthen the EU's health security framework, and foster the collection and utilisation of RWD

Interlaboratory test to characterize the cyclic behavior of bituminous interlayers: an overview of testing equipment and protocols

The performance assessment of multi-layered pavements strongly depends on the mechanical behavior of the interface between bituminous layers. So far, comprehensive studies have been carried out mainly using quasi-static laboratory tests focusing on the interlayer shear strength at failure. However, it is generally recognized that cyclic shear testing will lead to the determination of parameters which are more closely linked to the performance of pavements under traffic loading than the quasi-static shear tests. This paper outlines the research work that has been carried out within the Task Group 3 “Pavement multilayer system” of the RILEM TC 272-PIM. The activities focused on cyclic shear testing of interfaces in bituminous pavements involve an interlaboratory test with nine participating laboratories. The interface behavior was investigated through both direct shear and torque tests on double-layered specimens extracted from lab compacted slabs prepared by one of the laboratories. The different testing equipment and protocols used by the participating laboratories are presented, highlighting the variety of geometries, loading modes, and testing parameters.- (undefined