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Keywords: Charnley–Muller hip prosthesis, wear, wear particles, revision percentage
Published in DiRROS: 23.04.2025; Views: 82; Downloads: 43
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Abstract: This study validates the proposed polymerised structure, including tetrameric polynuclear species, of solid amorphous oxyhydroxide zirconium conversion coatings on cold-rolled steel using ToF-SIMS. Tetramers are formed at pH near 4 (and possibly higher), with thickness increasing over extended conversion times. EIS in simulated acid rain further demonstrates that optimal coating formation requires a pH of at least 4 and a sufficient conversion time for adequate thickness, confirmed by the high-frequency EIS loop. Tetramer forms were not observed when the coatings were prepared at lower pH or shorter conversion time, proving that the polymerisation step is crucial for obtaining the coatings offering adequate corrosion protection
Published in DiRROS: 23.04.2025; Views: 102; Downloads: 33
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Abstract: : (1) Background: Analyses of retrieved inserts allow for a better understanding of TKA failure mechanisms and the detection of factors that cause increased wear. The purpose of this implant retrieval study was to identify whether insert volumetric wear significantly differs among groups of common causes of total knee arthroplasty failure, whether there is a characteristic wear distribution pattern for a common cause of failure, and whether nominal insert size and component size ratio (femur-to-insert) influence linear and volumetric wear rates. (2) Methods: We digitally reconstructed 59 retrieved single-model cruciate-retaining inserts and computed their articular loadbearing surface wear utilizing an optical scanner and computer-aided design models as references. After comprehensively reviewing all cases, each was categorized into one or more of the following groups: prosthetic joint infection, osteolysis, clinical loosening of the component, joint malalignment or component malposition, instability, and other isolated causes. The associations between volumetric wear and causes of failure were estimated using a multiple linear regression model adjusted for time in situ. Insert linear penetration wear maps from the respective groups of failure were further processed and merged to create a single average binary image, highlighting a potential wear distribution pattern. The differences in wear rates according to nominal insert size (small vs. medium vs. large) and component size ratio (≤1 vs. >1) were tested using the Kruskal–Wallis test and the Mann– Whitney test, respectively. (3) Results: Patients with identified osteolysis alone and those also with clinical loosening of the component had significantly higher volumetric wear when compared to those without both causes (p = 0.016 and p = 0.009, respectively). All other causes were not significantly associated with volumetric wear. The instability group differentiated from the others with a combined peripheral antero-posterior wear distribution. Linear and volumetric wear rates showed no significant differences when compared by nominal insert size (small vs. medium vs. large, p = 0.563 and p = 0.747, respectively) or by component (femoral-to-insert) size ratio (≤1 vs. >1, p = 0.885 and p = 0.055, respectively). (4) Conclusions: The study found increased volumetric wear in cases of osteolysis alone, with greater wear when combined with clinical loosening compared to other groups. The instability group demonstrated a characteristic peripheral anterior and posterior wear pattern. Insert size and component size ratio seem not to influence wear rates.
Published in DiRROS: 23.04.2025; Views: 99; Downloads: 46
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Abstract: High-mountain lakes were historically fishless due to natural barriers, but human introductions have led to widespread fish presence. Although particularly intensive during the last decades, historical documents indicate introductions in European high mountains already during the 14th and 15th centuries, but they could have occurred before, provided the intensive land use of the high mountain had started earlier. We used ancient environmental DNA from lake sediments (sedDNA) to investigate this hypothesis. Fish ectoparasites from various clades were identified using the 18S rRNA gene in the sediment record of a deep, high-mountain Pyrenean lake, with Ichthyobodo (Kinetoplastea) being of particular interest due to its consistent occurrence. The study shows a continued presence of fish parasites in the lake since the 7th century, which coincides with the Late-Roman and Visigothic extensive mountain use for sheep pasturing as supported by nearby archeological remains and increased lake primary production evidenced by photosynthetic pigments.
Keywords: high-mountain lakes, fishless, sedimentary ancient DNA, sedDNA, ectoparasites, hydrobiology
Published in DiRROS: 23.04.2025; Views: 85; Downloads: 35
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Abstract: Introduction: In the European Alps, Pleistocene climate oscillations resulted in geographical range expansions and restrictions of species. Postglacial recolonizations often result in secondary contact hybridization of vicariant species, thereby creating hybrid zones with patterns of introgression. Here, we compare the genetic structure of two secondary contact hybrid zones between two vicariant willow species pairs occurring in the European Alpine System. Supplemented by morphological and ecological data, we try to understand the factors shaping the hybrid zones and their influence on geographical range filling patterns. Methods: RAD sequencing and morphometric data were used to characterize biogeographical history, genetic diversity and the hybrid zone of each species pair. Vegetation relevés and species distribution models provided ecological context and support. Key results: Results suggest that recolonization of the Alps happened from peripheral glacial refugia, resulting in broad secondary contact zones in the Eastern Alps in both species pairs. Both hybrid zones show introgression, but differ in symmetry and intensity of gene flow, in the type of introgressed loci, and in the geographical range. Habitat preferences and species distribution models do not indicate ecological barriers to recolonization. Conclusions: Hybrid zones do not only affect the genetic structure of species by gene flow and introgression, but also appear to impact the biogeographical patterns of species.
Keywords: hybridization, phylogeny, phylogeography, climatic oscillations, genus Salix
Published in DiRROS: 22.04.2025; Views: 103; Downloads: 38
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