Rotationally acquired four-dimensional optical coherence tomography of embryonic chick hearts using retrospective gating on the common central A-scan

We introduce a new method of rotational image acquisition for four-dimensional (4D) optical coherence tomography (OCT) of beating embryonic chick hearts. The rotational axis and the central A-scan of the OCT are identical. An out-of-phase image sequence covering multiple heartbeats is acquired at every angle of an incremental rotation of the deflection mirrors of the OCT system. Image acquisition is accomplished after a rotation of 180°. Comparison of a displayed live M-mode of the central A-scan with a reference M-mode allows instant detection of translational movements of the embryo. For calculation of 4D data sets, we apply an image-based retrospective gating algorithm using the phase information of the common central A-scan present in all acquired images. This leads to cylindrical three-dimensional data sets for every time step of the cardiac cycle that can be used for 4D visualization. We demonstrate this approach and provide a video of a beating Hamburger and Hamilton stage 16 embryonic chick heart generated from a 4D OCT data set using rotational image acquisition

Removal of temporary pacemaker after cardiac surgery in infants: A harmless procedure?

External pacemakers (PM) via temporary epicardial leads are routinely applied to infants and children during heart surgery, which usually, after an uneventful post surgical course, can be removed without complications. We report about two infants with complex congenital heart defects after cardiac surgery (arterial switch and Mustard operation for Transposition of the great arteries). Intraoperative these patients received temporary epicardial PM wires. Thirteen and 18 days post surgery, respectively, the PM wires were removed under electrocardiogram (ECG) monitoring. The patients showed acute ECG changes in terms of significant ST elevation during and after removing their pacing wires. Clinically, patients were stable and subsequent echocardiographic examination showed no evidence of myocardial dysfunction or pericardial effusion. In the course of time, patients showed no signs of arrhythmia or abnormal ECG changes. The decision to place temporary pacing wires during the cardiac surgery in patients with congenital heart defects should be considered carefully and their removal should occur under ECG monitoring as soon as the situation of the patient allows. It should be taken into consideration that a complication like this case may be related to delayed removal of temporary PM’s leads. © 2012 - IOS Press and the authors

Rapid inward migration of planets formed by gravitational instability

The observation of massive exoplanets at large separation from their host star, like in the HR 8799 system, challenges theories of planet formation. A possible formation mechanism involves the fragmentation of massive self-gravitating discs into clumps. While the conditions for fragmentation have been extensively studied, little is known of the subsequent evolution of these giant planet embryos, in particular their expected orbital migration. Assuming a single planet has formed by fragmentation, we investigate its interaction with the gravitoturbulent disc it is embedded in. Two-dimensional hydrodynamical simulations are used with a simple prescription for the disc cooling. A steady gravitoturbulent disc is first set up, after which simulations are restarted including a planet with a range of masses approximately equal to the clump's initial mass expected in fragmenting discs. Planets rapidly migrate inwards, despite the stochastic kicks due to the turbulent density fluctuations. We show that the migration timescale is essentially that of type I migration, with the planets having no time to open a gap. In discs with aspect ratio ~ 0.1 at their forming location, planets with a mass comparable to, or larger than Jupiter's can migrate in as short as 10000 years, that is, about 10 orbits at 100 AU. Massive planets formed at large separation from their star by gravitational instability are thus unlikely to stay in place, and should rapidly migrate towards the inner parts of protoplanetary discs, regardless of the planet mass.Comment: 13 pages, 10 figures, accepted for publication in MNRA

The BrainScaleS-2 Neuromorphic Platform — A Report on the Integration and Operation of an Open Science Hardware Platform within EBRAINS

This report presents the challenges encountered and the solutions created for the operation of the BrainScaleS neuromorphic platform, and the overall progress leading to this state at the end of the Human Brain Project (HBP)

Scalable continuous production of high quality HKUST-1 via conventional and microwave heating

Metal Organic Frameworks (MOFs) are materials with large surface areas and internal volumes, which result in a number of useful properties for applications such as catalysis, separations and gas storage. However, MOFs are challenging to produce at a large scale creating a barrier to becoming truly viable alternatives to current technologies. As a first step towards industrial scale manufacture, we demonstrate here the first scalable, continuous synthesis of high-quality HKUST-1 using ethanol as the solvent, resulting in a greener and potentially much more economical process (as solvent does not decompose and thus can be recycled). We also show that microwave heating can be used to produce HKUST-1 continuously, in timescales several orders of magnitude faster than by conventional heating. We demonstrate a novel approach to microwave assisted synthesis of HKUST-1, based on a recycle loop with microwave irradiation, which is scalable under both batch and continuous conditions and allows an independent control of microwave irradiation regime and the overall reaction time. The use of microwave heating for continuous production of HKUST-1 enabled STY of 400,000 kg m−3 d−1, which is higher than any production rates reported to date, even when using the preferred high yield solvent, DMF, and is 17 times more than the highest production rates reported to date for HKUST-1 in ‘ethanol-only’ systems