Fixation of osteochondral fragments in the human knee using Meniscus Arrows®

The aim of this study is to compare the hold in bone of Meniscus Arrows® and Smart Nails®, followed by the report of the results of the clinical application of Meniscus Arrows® as fixation devices. First, pull-out tests were performed to analyse the holdfast of both nails in bone. Statistical analysis showed no significant difference; therefore, the thinner Meniscus Arrow® was chosen as fixation device in the patient series of two patients with a symptomatic Osteochondritis dissecans fragment and three patients with an osteochondral fracture of a femur condyle. The cartilage margins were glued with Tissuecoll®. All fragments consolidated. Second look arthroscopy in three patients showed fixed fragments with stable, congruent cartilage edges. At an average follow-up period of 5 years no pain, effusion, locking, restricted range of motion or signs of osteoarthritis were reported. Based on the results of the pull-out tests and available clinical studies, Meniscus Arrows® and Smart Nails® are both likely to perform adequately as fixation devices in the treatment of Osteochondritis dissecans and osteochondral fractures in the knee. They both provide the advantage of one stage surgery. However, based on their smaller diameter, the Meniscus Arrows® should be preferred for this indication

Photoelektronenspektroskopische Untersuchung von Natriumkobaltoxidkathoden Messungen an Feststoffbatterien unter operando Bedingungen im Ultrahochvakuum

In der vorliegenden Arbeit wird das Material Natriumkobaltoxid als Kathodenmaterial für Interkalationsbatterien untersucht. Um Informationen zur elektronischen Struktur des Materials bei unterschiedlichen Interkalationsgraden (welche Ladezuständen in der Batterie entsprechen) zu erhalten, wurden Modellzellen unter Ultrahochvakuumbedingungen (UHV) hergestellt. Durch elektrochemische Deinterkalation im UHV konnten operando Messungen mittels Photoelektronenspektroskopie (XPS) durchgeführt werden. Dies stellt ein neuartiges Messverfahren dar, welches im Rahmen dieser Arbeit entwickelt wurde. Weitere Experimente mit Modellzellen befassten sich mit Röntgenabsorptionsmessungen (XAS) des Kathodenmaterials und Grenzflächenuntersuchungen zwischen Elektrolyt und Elektrodenmaterialien. Basierend auf den Modellexperimenten konnte ein detaillierteres Verständnis zur Entwicklung der elektronischen Struktur von Natriumkobaltoxid bei verschiedenen Spannungen gegenüber metallischem Natrium erlangt werden. Einflüsse der elektronischen Struktur auf Elektrodenpotential und Stabilität wurden diskutiert und mit dem bekannten Schichtgitteroxidkathodenmaterial Lithiumkobaltoxid verglichen

Photoelektronenspektroskopische Untersuchung von Natriumkobaltoxidkathoden Messungen an Feststoffbatterien unter operando Bedingungen im Ultrahochvakuum

In der vorliegenden Arbeit wird das Material Natriumkobaltoxid als Kathodenmaterial für Interkalationsbatterien untersucht. Um Informationen zur elektronischen Struktur des Materials bei unterschiedlichen Interkalationsgraden (welche Ladezuständen in der Batterie entsprechen) zu erhalten, wurden Modellzellen unter Ultrahochvakuumbedingungen (UHV) hergestellt. Durch elektrochemische Deinterkalation im UHV konnten operando Messungen mittels Photoelektronenspektroskopie (XPS) durchgeführt werden. Dies stellt ein neuartiges Messverfahren dar, welches im Rahmen dieser Arbeit entwickelt wurde. Weitere Experimente mit Modellzellen befassten sich mit Röntgenabsorptionsmessungen (XAS) des Kathodenmaterials und Grenzflächenuntersuchungen zwischen Elektrolyt und Elektrodenmaterialien. Basierend auf den Modellexperimenten konnte ein detaillierteres Verständnis zur Entwicklung der elektronischen Struktur von Natriumkobaltoxid bei verschiedenen Spannungen gegenüber metallischem Natrium erlangt werden. Einflüsse der elektronischen Struktur auf Elektrodenpotential und Stabilität wurden diskutiert und mit dem bekannten Schichtgitteroxidkathodenmaterial Lithiumkobaltoxid verglichen

Toward an Understanding of Thin-Film Transistor Performance in Solution-Processed Amorphous Zinc Tin Oxide (ZTO) Thin Films

Amorphous zinc tin oxide (ZTO) thin films are accessible by a molecular precursor approach using mononuclear zinc­(II) and tin­(II) compounds with methoxyiminopropionic acid ligands. Solution processing of two precursor solutions containing a mixture of zinc and tin­(II)–methoxyiminopropinato complexes results in the formation of smooth homogeneous thin films, which upon calcination are converted into the desired semiconducting amorphous ZTO thin films. ZTO films integrated within a field-effect transistor (FET) device exhibit an active semiconducting behavior in the temperature range between 250 and 400 °C, giving an increased performance, with mobility values between μ = 0.03 and 5.5 cm²/V s, with on/off ratios increasing from 10⁵ to 10⁸ when going from 250 to 400 °C. Herein, our main emphasis, however, was on an improved understanding of the material transformation pathway from weak to high performance of the semiconductor in a solution-processed FET as a function of the processing temperature. We have correlated this with the chemical composition and defects states within the microstructure of the obtained ZTO thin film via photoelectron spectroscopy (X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy), Auger electron spectroscopy, electron paramagnetic resonance spectroscopy, atomic force microscopy, and photoluminescence investigations. The critical factor observed for the improved performance within this ZTO material could be attributed to a higher tin concentration, wherein the contributions of point defects arising from the tin oxide within the final amorphous ZTO material play the dominant role in governing the transistor performance

The Twannberg iron meteorite strewn field in the Swiss Jura mountains: insights for Quaternary environmental conditions

The ~ 10 km 2 strewn field of the Twannberg type IIG iron meteorite is located in the Swiss Jura Mountains, 30 km northwest of Bern. The strewn field has been mapped by a group of citizen scientists since 2006, yielding more than 2000 meteorite fragments with a total mass of 152.7 kg until the end of 2022. With a terrestrial age of 176 ± 19 ka and a minimum pre-atmospheric mass of ~ 250 t, the Twannberg meteorite is a local time marker in an area with a poorly-known paleoenvironmental history. The Twannberg strewn field is located just outside of the maximum extent of ice during the Last Glacial Maximum (LGM). On the Mont Sujet, meteorites are size-sorted in a 6-km long section of the primary strewn field (altitude 945-1370 m a.s.l.), indicating a fall direction from east-northeast to west-southwest (azimuth approximately 250°). On the Twannberg plateau and in the Twannbach gorge, meteorites are not size-sorted and occur in a ~ 5.7-km long area associated with till and recent stream sediments (altitude 430-1075 m a.s.l.). The mass distribution of meteorites on the Twannberg plateau demonstrate that these meteorites were not found where they fell but that they must have been transported up to several km by glacier ice flow after the fall. The distribution of meteorites and of glacially transported Alpine clasts on the Mont Sujet and on the Chasseral chain indicates the presence of local ice caps and of an approximately 200-m higher Alpine ice surface with respect to the LGM at the time of fall. This high ice level during MIS 6 (Marine Isotopic Stage 6, 191-130 ka) indicated by the meteorite distribution is consistent with surface exposure ages of 50-144 ka from nearby resting erratic boulders at altitudes of up to 1290 m a.s.l., including the newly dated Jobert boulder (63 ka). These boulders indicate an ice level ~ 400 m higher than during LGM at a time not later than MIS 6. Post-LGM luminescence ages of loesscontaining meteorites on the Mont Sujet and 14 C ages of materials associated with meteorite finds indicate relatively young pedoturbation and increased oxidation of meteorites since ~ 7300 cal BP, possibly correlated with deforestation and enhanced erosion resulting from increased human activities since the Neolithic. This study shows that Twannberg meteorites in their palaeoenvironmental context provide valuable information about ice levels and transport directions during MIS 6 and about their interaction with the post-LGM environmental conditions. The unique Twannberg strewn field has the potential to reveal more valuable information