A next-generation liquid xenon observatory for dark matter and neutrino physics

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector

Haemodynamic Issues with Transcatheter Aortic Valve Implantation

Transcatheter aortic valves are typically implanted inside the native (or failed bioprosthetic’s) leaflets, permanently forcing the old leaflets open into a pseudo-cylindrical condition. Due to the passive nature of heart valves, the dynamics of the surrounding fluid environment is critical to their optimum performance. Following intervention, the haemodynamics of the region would ideally be returned to their healthy, physiological state, but major alterations are currently inevitable, such as increased peak flow velocity, the presence of stagnation regions, and increased haemolytic fluid environments. These leaflets reduce the volume of and restrict the flow into the Valsalva’s sinuses, and minimise the development of vortices and associated flow structures, which would aid washout and valve closure. Despite these differences to the healthy condition, implantation of these devices offers much improved flow from that of a moderately stenotic valve, with reduced transvalvular systolic pressure drop, peak blood velocity, and shear stress, which normally outweighs the disadvantages highlighted above, especially for high-risk patients

On the Mechanics of Transcatheter Aortic Valve Replacement

Transcatheter aortic valves (TAVs) represent the latest advances in prosthetic heart valve technology. TAVs are truly transformational as they bring the benefit of heart valve replacement to patients that would otherwise not be operated on. Nevertheless, like any new device technology, the high expectations are dampened with growing concerns arising from frequent complications that develop in patients, indicating that the technology is far from being mature. Some of the most common complications that plague current TAV devices include malpositioning, crimp-induced leaflet damage, paravalvular leak, thrombosis, conduction abnormalities and prosthesis-patient mismatch. In this article, we provide an in-depth review of the current state-of-the-art pertaining the mechanics of TAVs while highlighting various studies guiding clinicians, regulatory agencies, and next-generation device designers