Matched Pair-Analyse winkelstabiler Plattenosteosynthesen am proximalen Humerus: PHILOS versus NCB-PH

Proximale Humerusfrakturen gehören zu den häufigsten Frakturen des Menschen. In der operativen Versorgung dieser Verletzung gelten winkelstabile Plattenosteosynthesen als Goldstandard. Da es in der Literatur bisher keine eindeutige Datenlage zur Verwendung von monoaxial bzw. polyaxial ausrichtbaren Schrauben gibt, war das Ziel dieser Studie der Vergleich von operativen und funktionellen Ergebnissen mit zwei sich diesbezüglich unterscheidenden Implantaten. Hierzu wurden die NCB-Platte (polyaxial), sowie die PHILOS-Platte (monoaxial) ausgewählt. Als Design für diese Studie wurde eine Matched Pair-Analyse gewählt in die insgesamt 76 Patienten (=38 Paare) eingeschlossen werden konnten. Matching-Kriterien waren das Alter und Geschlecht der Patienten, sowie der Frakturtyp nach AO-Klassifikation. Hinsichtlich der operativen Daten (OP-/Röntgendauer, Blutverlust, postoperativer stationärer Aufenthalt) unterschieden sich beide Kollektive nur geringfügig. Bemerkenswert ist jedoch die bei den PHILOS-Patienten mehr als doppelt so hohe Komplikationsrate gegenüber den NCB-Patienten (9 vs. 4 Fälle). Das funktionelle Ergebnis wurde anhand des Constant-Murley Scores und visuellen Analogskalen beurteilt. Mit 61,8 Punkten lag der Wert der NCB-Patienten im Constant-Murley Score etwa 5 Punkte über dem der PHILOS-Patienten. Auch mit dem Behandlungsergebnis insgesamt, welches auf einer visuellen Analogskala beurteilt wurde, waren die NCB-Patienten besser zufrieden. Hingegen unterschieden sich die Kollektive nur geringfügig bezüglich der rein subjektiven Beweglichkeit des frakturierten Armes, welche ebenfalls auf einer visuellen Analogskala eingeschätzt wurde. Abschließend lässt sich feststellen, dass Patienten, die mit einem Implantat mit polyaxial ausrichtbaren Schrauben versorgt wurden, in dieser Studie in geringerem Maße von Komplikationen betroffen waren und sowohl in subjektiver vor allem aber objektiver Hinsicht ein besseres funktionelles Ergebnis erreichten

Outpatient speech and language therapy via videoconferencing in Germany during the COVID-19 pandemic: Experiences of therapists / Videotherapie in der ambulanten Logopädie/Sprachtherapie in Deutschland während der COVID-19 Pandemie: Erfahrungen von Therapeut/innen

During the COVID-19 pandemic, videoconferencing as a synchronous form of telepractice service delivery models received a boost. In Germany, online-only sessions are not a standardised means of healthcare provision, while telepractice is already well established internationally. This study examines videoconferencing in outpatient speech and language therapy during the first period of the COVID-19 pandemic in Germany. The experiences of therapists are reported in this study

Retention of 226^{226}Ra by barite: The role of internal porosity

The role of internal macropores and nano-scale pores for the uptake of 226Ra into barite was studied via scanning and transmission electron microscopy as well as focused ion beam methods. A temporal evolution of the internal microstructure and the Ra distribution was observed on samples taken from long-term Ra uptake experiments. The results of this study clearly show a significant impact of the presence of Ra leading to a complete reconstruction of the internal barite microstructure, whereas the microstructure of Ra-free reference samples remained unchanged. The initial internal barite microstructure contains a connected network of macropores and a layered structure of nano-scale pores which, in the presence of Ra, coalesced in favor of larger pores during the experiment. A clear relationship between the Ra uptake and the internal porosity was observed by high-resolution STEM-EDX mappings. Starting from strongly enhanced Ra concentrations in the solid in the vicinity of the pores, Ra is temporarily inhomogeneously distributed within the barite particles. At later stages of the long-term experiment the Ra distribution becomes homogenous while nano-scale and macro-scale pores disappear. In conclusion, the uptake of Ra into barite takes place by a special case of dissolution/reprecipitation from the inside of the particle to the outside

Ra Uptake by the Sr-Rich Solid Solution of (Sr, Ba)SO4

Solid solution formation is an important mechanism of radionuclide uptake by mineral phases which is favored in natural systems due to a lowered configurational entropy. Recent studies have shown that the formationof a (Ba,Ra)SO4 solid solution significantly reduces the solubility of 226Ra in aqueous systems. This result is very relevant for the direct disposal of spent nuclear fuel in a deep geological formation, where 226Ra would dominate the dose after 100,000 years [1]. In natural systems SrSO4 often occurs along with BaSO4 implying that Ra-uptake should be assessed within the system of (Sr,Ba,Ra)SO4 + H2O. A recent thermodynamic modelling study [2] predicted a significant uptake of Ra into the ternary (Sr,Ba,Ra)SO4 solid-solution. Here we present results of long-term batch-recristallisation experiments on Ra-uptake in a Sr-rich part of the ternary system. A mechanical mixture of celestite with a small amount of barite and a (Sr,Ba)SO4 solid solution of equivalent comoposition were put into a contact with 226Ra,aq. We observed a significant uptake of 226Ra in both cases proceeding via the formation of the minor ternary Sr-, Ba- and Ra-rich phase within the major Sr-rich phase. In longer experiments the ternary phase disappeared leading to the formation of a mixture of Sr- and Ba-rich phases, within which Ra could not be detected by scanning transmission electron microscopy-energy-dispersive X-ray spetroscopy (STEM-EDX). The final 226Ra concentrations in both experiments were similar and close to predicted levels. The formation of the intermediate phase is interpreted based on structural and kinetic considerations. [1] Norrby, S. et al. (1997). “SKI SITE-94 Saekerhetsanalys foer Djupfoervar iett Kristallint berg”.Stockholm, Sweden. [2] Vinograd et al. (2018). Applied Geochemistry, in press