13 research outputs found

    Off-pump coronary artery bypass (OPCAB) in complex coronary artery bypass procedures – a report of four cases and review of the literature

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    Off-pump coronary artery bypass (OPCAB) surgery is a procedure that is still not widely used by all cardiac surgeons. In the USA about 20-25% of coronary artery bypass graft (CABG) surgery is done offpump. Current literature suggests that both OPCAB and CABG with cardiopulmonary bypass have similar mortality rates, but OPCAB surgery does offer less morbidity, and advantages in terms of mortality and stroke rates in certain high risk patients. We discuss the role of OPCAB surgery in high risk patients, especially redo operations through a left thoracotomy to protect an intact internal mammary artery (LIMA) graft to the left anterior descending artery (LAD) and in patients with a calcified ascending aorta. Four case reports are used as examples and the literature is reviewed, which shows a superior outcome with OPCAB surgery in these complicated cases

    Abnormal Hair Development and Apparent Follicular Transformation to Mammary Gland in the Absence of Hedgehog Signaling

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    We show that removing the Shh signal tranducer Smoothened from skin epithelium secondarily results in excess Shh levels in the mesenchyme. Moreover, the phenotypes we observe reflect decreased epithelial Shh signaling, yet increased mesenchymal Shh signaling. For example, the latter contributes to exuberant hair follicle (HF) induction, while the former depletes the resulting follicular stem cell niches. This disruption of the niche apparently also allows the remaining stem cells to initiate hair formation at inappropriate times. Thus, the temporal structure of the hair cycle may depend on the physical structure of the niche. Finally, we find that the ablation of epithelial Shh signaling results in unexpected transformations: the follicular outer root sheath takes on an epidermal character, and certain HFs disappear altogether, having adopted a strikingly mammary gland-like fate. Overall, our study uncovers a multifaceted function for Shh in sculpting and maintaining the integrity and identity of the developing HF

    The biological principles of swarm intelligence

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    International audienceThe roots of swarm intelligence are deeply embedded in the biological study of self-organized behaviors in social insects. From the routing of traffic in telecommunication networks to the design of control algorithms for groups of autonomous robots, the collective behaviors of these animals have inspired many of the foundational works in this emerging research field. For the first issue of this journal dedicated to swarm intelligence, we review the main biological principles that underlie the organization of insects' colonies. We begin with some reminders about the decentralized nature of such systems and we describe the underlying mechanisms of complex collective behaviors of social insects, from the concept of stigmergy to the theory of self-organization in biological systems. We emphasize in particular the role of interactions and the importance of bifurcations that appear in the collective output of the colony when some of the system's parameters change. We then propose to categorize the collective behaviors displayed by insect colonies according to four functions that emerge at the level of the colony and that organize its global behavior. Finally, we address the role of modulations of individual behaviors by disturbances (either environmental or internal to the colony) in the overall flexibility of insect colonies. We conclude that future studies about self-organized biological behaviors should investigate such modulations to better understand how insect colonies adapt to uncertain worlds

    Post-conjunction detection of β Pictoris b with VLT/SPHERE

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    accepted by A&AInternational audienceContext. With an orbital distance comparable to that of Saturn in the solar system, β Pictoris b is the closest (semi-major axis ≃9 au) exoplanet that has been imaged to orbit a star. Thus it offers unique opportunities for detailed studies of its orbital, physical, and atmospheric properties, and of disk-planet interactions. With the exception of the discovery observations in 2003 with NaCo at the Very Large Telescope (VLT), all following astrometric measurements relative to β Pictoris have been obtained in the southwestern part of the orbit, which severely limits the determination of the planet’s orbital parameters.Aims. We aimed at further constraining β Pictoris b orbital properties using more data, and, in particular, data taken in the northeastern part of the orbit.Methods. We used SPHERE at the VLT to precisely monitor the orbital motion of beta β Pictoris b since first light of the instrument in 2014.Results. We were able to monitor the planet until November 2016, when its angular separation became too small (125 mas, i.e., 1.6 au) and prevented further detection. We redetected β Pictoris b on the northeast side of the disk at a separation of 139 mas and a PA of 30° in September 2018. The planetary orbit is now well constrained. With a semi-major axis (sma) of a = 9.0 ± 0.5 au (1σ), it definitely excludes previously reported possible long orbital periods, and excludes β Pictoris b as the origin of photometric variations that took place in 1981. We also refine the eccentricity and inclination of the planet. From an instrumental point of view, these data demonstrate that it is possible to detect, if they exist, young massive Jupiters that orbit at less than 2 au from a star that is 20 pc away

    Terrestrial very-long-baseline atom interferometry: Workshop summary

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    This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more kilometer--scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.</jats:p
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