Explore the vast range of titles available.

This work describes the development and optimization of the radiochemical separation of 147 Pm and 151 Sm. The two main challenges addressed were: the radiochemical separation of the lanthanides by using LN Resin and DGA,N Resin, and the quantification of the chemical recovery of 147 Pm with a non-isotopic analogue ( i.e. neodymium). The applicability of radiochemical separation procedures was investigated by using spiked samples. The optimized radiochemical separation procedure by using LN Resin was applied to a reactor cooling water primary coolant sample with an automated system. Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) was used to determine the chemical recoveries.

Background Heavy calcifications in severe aortic stenosis (AS) pose a major challenge in patients undergoing transcatheter aortic valve replacement (TAVR). Only a few studies have addressed the performance of different transcatheter heart valves (THV) in this subgroup of patients. Objectives We aimed to investigate the outcomes of the self-expanding Medtronic CoreValve Evolut valve frame and the balloon-expandable Edwards SAPIEN-3/3 Ultra THV in this challenging patient population. Materials and methods This was a multicenter registry including a total of 1513 patients with heavily calcified AS undergoing TAVR. The primary endpoint was the incidence and degree of paravalvular leak (PVL) after TAVR. Secondary endpoints were post-implant hemodynamics as well as clinical endpoints according to the VARC-3 definitions. Results The CoreValve Evolut R but not the Evolut PRO showed significantly higher rates of PVL compared to the SAPIEN-3/3 Ultra (44.8% vs. 29.5% for mild PVL, p < 0.001), while there was no significant difference in ≥ moderate PVL between both groups (p = 0.399). The CoreValve Evolut R and Evolut PRO showed superior THV hemodynamics compared to the SAPIEN-3/3 Ultra group. These findings were confirmed in a propensity score-matched analysis. There were no significant differences regarding short-term outcomes including permanent pacemaker implantation and all-cause mortality between the three groups. Conclusion In patients with severely calcified AS, both CoreValve Evolut PRO and SAPIEN-3/3 Ultra THV showed lower rates of PVL than the CoreValve Evolut R. The self-expanding CoreValve platform had superior post-implant hemodynamics than the SAPIEN-3/3 Ultra system. Graphical Abstract

A search for double-beta decay of 190Pt and 198Pt with emission of γ-ray quanta was realized at the HADES underground laboratory with a 148 g platinum sample measured by two ultralow-background HPGe detectors over 8946 h. The isotopic composition of the platinum sample has been measured with high precision using inductively coupled plasma mass spectrometry. New lower limits for the half-lives of 190Pt relative to different channels and modes of the decays were set on the level of limT1/2∼1014–1016 year. A possible exact resonant 0νKN transition to the 1,2 1326.9 keV level of 190Os is limited for the first time as T1/2≥2.5×1016 year. A new lower limit on the double-beta decay of 198Pt to the first excited level of 198Hg was set as T1/2≥3.2×1019 year, one order of magnitude higher than the limit obtained in the previous experiment.

The first ever search for α decays to the first excited state in Yb was performed for six isotopes of hafnium (174, 176, 177, 178, 179, 180) using a high purity Hf sample of natural isotopic abundance with a mass of 179.8 g. For 179 Hf, also α decay to the ground state of 175 Yb was searched for thanks to the β -instability of the daughter nuclide 175 Yb. The measurements were conducted using an ultra-low-background HPGe-detector system located 225 m underground. After 75 days of data taking no decays were detected but lower bounds for the half-lives of the decays were derived on the level of lim T 1 / 2 ∼ 10 15 - 10 18  a. The decay with the shortest half-life based on theoretical calculation is the decay of 174 Hf to the first 2 + 84.3 keV excited level of 170 Yb. The experimental lower bound was found to be T 1 / 2 ≥ 3.3 × 10 15 a.

Approximately 30 % of patients suffering from severe valvular heart disease, such as mitral valve regurgitation are non-compliant to the gold standard of minimally invasive surgery, reconstruction or valve replacement. The number of these mostly old patients with severe comorbidities is increasing; therefore, transcatheter interventions have been developed to address an unmet clinical need and may be an alternative therapeutic option to the reference standard. Apart from the successful MitraClip therapy, alternative transcatheter reconstruction technologies are being developed. As with transcatheter aortic valve implantation (TAVI) procedures, the off-pump implantation of a valved stent into the mitral position mainly via a transapical approach will be of great benefit. Recently, the feasibility of transcatheter mitral valved stent implantation in high-risk patients has already been reported.

Using the NAXSUN technique developed at the JRC-Geel, the cross section functions for the neutron induced reactions 187 Re(n,p) 187 W and 185 Re(n,3n) 183 Re have been measured in the energy range between 13.08 MeV and 19.5 MeV. These data are the first experimentally obtained values for those nuclear reactions in this neutron energy range. Obtained results have been compared with existing evaluated data from ENDF/B-VII 0, JEFF 3.3, JEFF 3.2, BROND 3.1, JEF - 2.2, JENDL, ROSFO ND-2010, TENDL-2017, EAF-2010, FENDL-3.1c. The TALYS 1.9 and EMPIRE 3.2.3 calculations were performed using different available models and calculations using several semi-empirical existing formulas. A comparison between theoretical model calculations and experimental results was made.

The aim of this study was the quantification of the apical fixation forces of mitral valved stents for the first time. A test set-up was developed to measure the forces acting on the apical fixation of mitral valved stents. Twenty pigs received a self-expanding valved stent in the mitral position via a transapical approach in an off-pump procedure. Following stent deployment in the beating heart, the apical fixation forces were recorded following a standardized protocol and normalized. The apical fixation force of two different valved stent designs (AP: sole apical fixation, n  = 10; SA: additional sub-annular fixation, n  = 10) was compared to quantify the impact of the design change. Force measurement was successfully conducted in 18 of 20 animals (design AP: n  = 10; design SA: n  = 8). Evaluation showed higher mean forces and amplitude in the group with sole apical fixation ( p  = 0.046; Table 1). The impact of the additional sub-annular fixation was shown by a significant reduction of the force acting upon the apex of the heart. Quantification of these in vivo forces provides important information about the impact of different stent designs and might provide an objective parameter for stent performance evaluation in clinical application.

The technique for measuring neutron activation cross-sections using wide energy neutron beams (NAXSUN) was recently developed at JRC-Geel . This method is based on the detection of the gamma activity induced by the activation of the samples in different but overlapping neutron fields and following an unfolding procedure. In the present work, measurements of the cross-section functions by the NAXSUN technique for the (n,a), (n,2n), (n,p) and (n,3n) reactions on rhenium isotopes 185Re and 187Re were performed. The results are the first experimental data for the mentioned reaction cross-sections in the energy range 13.0–19.5 MeV. The obtained data are of interest for possible applications of Re in nuclear technology and medicine.

Zusammenfassung Die schweren Mitralklappeninsuffizienzen nehmen zu und können bei 30 % der meist älteren Patienten mit schwersten Nebenerkrankungen nicht mit dem Goldstandard der minimal-invasiven Operation, einer Rekonstruktion oder einem Klappenersatz versorgt werden. Aufgrund dieser Tatsache werden Transkathetertechniken entwickelt, die als Alternative zum chirurgischen Standard diese klinische Versorgung sicherstellen. Ziel ist es dabei, die Mitralinsuffizienz aufzuheben. Neben der erfolgreichen MitraClip-Therapie werden alternative Transkatheterrekonstruktionstechnologien entwickelt. Wie bei den TAVI-Prozeduren werden darüber hinaus auch Klappenstents für die Mitralposition entwickelt, die hauptsächlich transapikal und „off-pump“ auch schon am Patienten eingesetzt werden.

Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of Ge by operating bare detectors, made of germanium with an enriched Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10 counts keV kg yr . This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 10 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 10 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.