Investigating the Influence of High-Speed Gantry Rotation in Cardiac CT on Motion Artifacts in Aortic Stenosis Patients Not Premedicated with β-Blockers: The FAST-CCT Randomized Trial Protocol.

Coronary CT angiography (CCTA) is increasingly used as a non-invasive tool to assess coronary artery disease (CAD). However, CCTA is subject to motion artifacts, potentially limiting its clinical utility. Despite faster (0.35 and 0.28 s/rot) gantry rotation times, low (60-65 bpm) heartbeat is recommended, and the use of β-blockers is often needed. Technological advancements have resulted in the development of faster rotation speeds (0.23 s/rot). However, their added value in patients not premedicated with β-blockers remains unclear. This prospective single-center, two-arm, randomized, controlled trial aims to assess the influence of fast rotation on coronary motion artifacts, diagnostic accuracy of CCTA for CAD, and patient safety. We will randomize a total of 142 patients aged ≥ 50 scheduled for an aortic stenosis work-up to receive CCTA with either a fast (0.23) or standard (0.28 s/rot) gantry speed. rate of CCTAs with coronary motion artifacts hindering interpretation. assessable coronary segments rate, diagnostic accuracy against invasive coronary angiography (ICA), motion artifact magnitude per segment, contrast-to-noise ratio (CNR), and patient ionizing radiation dose. The local ethics committee has approved the protocol. Potential significance: FAST-CCT may improve motion artifact reduction and diagnosis quality, thus eliminating the need for rate control and β-blocker administration. gov identifier: NCT05709652

Water induced sediment levitation enhances downslope transport on Mars

On Mars, locally warm surface temperatures (~293 K) occur, leading to the possibility of (transient) liquid water on the surface. However, water exposed to the martian atmosphere will boil, and the sediment transport capacity of such unstable water is not well understood. Here, we present laboratory studies of a newly recognized transport mechanism: “levitation” of saturated sediment bodies on a cushion of vapor released by boiling. Sediment transport where this mechanism is active is about nine times greater than without this effect, reducing the amount of water required to transport comparable sediment volumes by nearly an order of magnitude. Our calculations show that the effect of levitation could persist up to ~48 times longer under reduced martian gravity. Sediment levitation must therefore be considered when evaluating the formation of recent and present-day martian mass wasting features, as much less water may be required to form such features than previously thought

The flyby anomaly: a multivariate analysis approach

[EN] The flyby anomaly is the unexpected variation of the asymptotic post-encounter velocity of a spacecraft with respect to the pre-encounter velocity as it performs a slingshot manoeuvre. This effect has been detected in, at least, six flybys of the Earth but it has not appeared in other recent flybys. In order to find a pattern in these, apparently contradictory, data several phenomenological formulas have been proposed but all have failed to predict a new result in agreement with the observations. In this paper we use a multivariate dimensional analysis approach to propose a fitting of the data in terms of the local parameters at perigee, as it would occur if this anomaly comes from an unknown fifth force with latitude dependence. Under this assumption, we estimate the range of this force around 300 km .Acedo Rodríguez, L. (2017). The flyby anomaly: a multivariate analysis approach. Astrophysics and Space Science. 362(2):1-7. doi:10.1007/s10509-017-3025-zS173622Acedo, L.: Adv. 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Anomalous accelerations in spacecraft flybys of the Earth

[EN] The flyby anomaly is a persistent riddle in astrodynamics. Orbital analysis in several flybys of the Earth since the Galileo spacecraft flyby of the Earth in 1990 have shown that the asymptotic post-encounter velocity exhibits a difference with the initial velocity that cannot be attributed to conventional effects. To elucidate its origin, we have developed an orbital program for analyzing the trajectory of the spacecraft in the vicinity of the perigee, including both the Sun and the Moon¿s tidal perturbations and the geopotential zonal, tesseral and sectorial harmonics provided by the EGM96 model. The magnitude and direction of the anomalous acceleration acting upon the spacecraft can be estimated from the orbital determination program by comparing with the trajectories fitted to telemetry data as provided by the mission teams. This acceleration amounts to a fraction of a mm/s2 and decays very fast with altitude. 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Formation of gullies on Mars by debris flows triggered by CO_2 sublimation

Martian gully landforms resemble terrestrial debris flows formed by the action of liquid water and have thus been interpreted as evidence for potential habitable environments on Mars within the past few millennia. However, ongoing gully formation has been detected under surface conditions much too cold for liquid water, but at times in the martian year when a thin layer of seasonal CO_2 frost is present and defrosting above the regolith. These observations suggest that the CO_2 condensation–sublimation cycle could play a role in gully formation. Here we use a thermo-physical numerical model of the martian regolith underlying a CO_2 ice layer and atmosphere to show that the pores beneath the ice layer can be filled with CO_2 ice and subjected to extreme pressure variations during the defrosting season. The subsequent gas fluxes can destabilize the regolith material and induce gas-lubricated debris flows with geomorphic characteristics similar to martian gullies. Moreover, we find that subsurface CO_2 ice condensation, sublimation and pressurization occurs at conditions found at latitudes and slope orientations where gullies are observed. We conclude that martian gullies can result from geologic dry ice processes that have no terrestrial analogues and do not require liquid water. Such dry ice processes may have helped shape the evolution of landforms elsewhere on the martian surface

Anomalies cardiaques fœtales : diagnostic prénatal et prise en charge périnatale

International audienceL'incidence des cardiopathies congénitales est voisine de 1 % des naissances d'enfants vivants, dont environ 30 à 40 % sont des formes sévères. Elles sont responsables à elles seules de la moitié de la mortalité infantile par malformations. Les cardiopathies malformatives sont accessibles au diagnostic prénatal par échographie. Le diagnostic prénatal des cardiopathies congénitales permet d'éliminer des malformations associées, de discuter d'une vérification du caryotype fœtal, la recherche d'anomalie génétique via l'utilisation de puce à acide désoxyribonucléique (ADN) et, après un examen d'expertise de l'anatomie cardiaque, de préciser le pronostic et les possibilités de prise en charge postnatale. Environ 80 % des cardiopathies congénitales sont dépistés en prénatal dans le groupe à bas risque au cours des examens de dépistage des malformations à 22 ou 32 semaines d'aménorrhée (SA). La réalisation systématique des trois coupes de référence rend possible le diagnostic de la majorité des cardiopathies malformatives. Pour le groupe à risque accru pour les malformations cardiaques - antécédent familial de cardiopathie congénitale, exposition à des toxiques embryonnaires, pathologie maternelle, augmentation de la clarté nucale supérieure à 3,5 mm au 1er trimestre -, il est possible d'effectuer une première vérification de l'anatomie du cœur fœtal vers 13 à 14 SA. Dans le cas des cardiopathies isolées, le diagnostic prénatal permet une organisation de la naissance dans une structure adaptée permettant, en fonction du type de la cardiopathie, une prise en charge optimale de l'enfant après la naissance

Percutaneous endovascular biopsy of intravascular masses: efficacy and safety in establishing pre-therapy diagnosis.

To evaluate the efficacy and safety of percutaneous endovascular biopsy (PEB) in intravascular filling-defect lesions (IVLs) of the great vessels. We retrospectively reviewed 19 patients (age 65 ± 12 years), 11 men and eight women, who underwent PEB for IVLs, between March 2004 and November 2014. All PEBs were performed for early diagnosis and/or characterization of the IVL, or in case of reasonable doubt about the IVL nature. Pre-intervention imaging work-up included CT, MRI and/or PET-CT. PEBs were obtained with a 7F biopsy forceps device. Clinical profile, procedure technical success and safety, and clinical success were evaluated. PEB was technically successful in all patients (mean of two samples per IVL). No intra- or post-procedural complications were reported. Histopathological analysis provided a diagnosis in all PEBs with a clinical success of 100%. Of the 19 IVLs, 14 were malignant (74%). The most frequent malignant lesion observed was leiomyosarcoma (29%). Benign lesions (26%) included three thrombi (pulmonary artery) and two myxomas. PEB is a safe and efficient procedure providing the most effective technique to obtain a tissue sample of high diagnostic quality, which serves to establish early diagnosis in patients with suspected malignant lesions. • Intravascular filling-defect lesions are related to both benign conditions and malignant tumours. • Endovascular biopsy is indicated in case of doubt about intravascular lesion nature. • Percutaneous endovascular biopsy is a safe technique. • Endovascular biopsy provides tissue samples leading to correct histopathological analysis. • Percutaneous endovascular biopsy provides early diagnosis of malignant intravascular lesions