Complications following transcatheter edge-to-edge mitral valve repair: Personal experience and review of the literature

Mitral valve dysfunction affects around 2% of the population and its incidence is still increasing, making it the second most common valvular heart disease, after aortic stenosis. Depending on the etiology of the disease, it can be classified into primary or secondary mitral regurgitation. The first line of treatment is optimal medical therapy. If ineffective, mitral valve intervention can be considered. For patients disqualified from surgical treatment, transcatheter edge-to-edge repair with the use of MitraClip may be considered. Over 100,000 MitraClip procedures have been performed which makes this the most established transcatheter technique for the treatment of severe mitral regurgitation. The aim of this review is to discuss the technical details of the MitraClip procedure, clinical evidence regarding the efficacy of MitraClip, complications related to the clip implantation alongside with acute complications based on the currently available evidence and clinical experience

Polytypism Study in SiC Epilayers Using Electron Backscatter Diffraction

score: 0collation: 251-25

Characterization of AIIIBV\mathrm{A^{III}B^V} superlattices by means of synchrotron diffraction topography and high-resolution X-ray diffraction

New possibilities are presented for the characterization of A$^{III}$B$^V$ mixed superlattice compounds by the complementary use of synchrotron diffraction topography and rocking curves. In particular, using a synchrotron white beam and the section diffraction pattern of a 5 µm slit taken at a 10 cm film-to-crystal distance, it was possible to reproduce a set of stripes corresponding to interference fringes. These are analogous to the interference maxima revealed in high-resolution rocking curves, but are created by the changes in orientation of the planes inclined to the surface which are induced by unrelaxed strain. The section diffraction topographic method enabled examination of the sample homogeneity along the narrow intersecting beam. This was important in the case of the present sample containing a twin lamella in the InP substrate wafer. Both the section and projection Bragg case topographic methods enabled the crystallographic identification of the twin lamella. Another characteristic feature indicated in the section topography was the bending of the stripes corresponding to the superlattice peaks close to the boundaries of the twin lamella. The most probable interpretation of this phenomenon is an increase in the thickness of the deposited layers close to the lamella, together with possible changes in the chemical composition, leading to a decrease in the mean lattice parameter in the superlattice

Structure and thermal expansion of Ca9Gd(VO4)7\mathrm{Ca_{9}Gd(VO_{4})_{7}}: A combined powder-diffraction and dilatometric study of a Czochralski-grown crystal

Materials of the Ca$_9$RE(VO$_4$)$_7$ (CRVO) formula (RE = rare earth) and whitlockite-related structures are considered for applications in optoelectronics, e.g., in white-light emitting diodes and lasers. In the CRVO structure, the RE atoms are known to share the site occupation with Ca atoms at two or three among four Ca sites, with partial occupancy values depending on the choice of the RE atom. In this work, the structure and quality of a Czochralski-grown crystal of this family, Ca$_9$Gd(VO$_4$)$_7$ (CGVO), are studied using X-ray diffraction methods. The room-temperature structure is refined using the powder diffraction data collected at a high-resolution synchrotron beamline ID22 (ESRF, Grenoble); for comparison purposes, a laboratory diffraction pattern was collected and analyzed, as well. The site occupancies are discussed on the basis of comparison with literature data of isostructural synthetic crystals of the CRVO series. The results confirm the previously reported site-occupation scheme and indicate a tendency of the CGVO compound to adopt a Gd-deficient composition. Moreover, the thermal expansion coefficient is determined for CGVO as a function of temperature in the 302–1023 K range using laboratory diffraction data. Additionally, for CGVO and six other single crystals of the same family, thermal expansion is studied in the 298–473 K range, using the dilatometric data. The magnitude and anisotropy of thermal expansion, being of importance for laser applications, are discussed for these materials

Investigation of damage induced by intense femtosecond XUV pulses in silicon crystals by means of white beam synchrotron section topography

Silicon crystalline samples were exposed to intense single pulses of XUV radiation (λ=13.5 nm) what lead to melting and ablation of the surface material. The deformation field around craters along the whole thickness of silicon wafers was observed by means of the synchrotron transmission section topography using the beam perpendicular to the surface of the sample. The geometrical shape and depth extension around craters was evaluated based on numerous, dense series of section topographs spaced by 10 µm. In the topographs we observed the direct image connected with the boundary of the crater associated with some deformation of the Kato fringes. The evaluated depth extension, different for individual craters, was in the range of 30–100 µm. The depth values were confirmed also by evaluations based on the Bragg case section topographs.It was possible to reproduce the contrast of the craters in transmission section topographs by numerical simulation based on integration of the Takagi–Taupin equations. The damage of the crystal defects connected with craters was approximated as droplet-like inclusions