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Objectives: Bisphosphonates (BP) are the first-line treatment for preventing fragility fractures. However, concern regarding their efficacy is growing because bisphosphonate is associated with over-suppression of remodelling and accumulation of microcracks. While dual-energy X-ray absorptiometry (DXA) scanning may show a gain in bone density, the impact of this class of drug on mechanical properties remains unclear. We therefore sought to quantify the mechanical strength of bone treated with BP (oral alendronate), and correlate data with the microarchitecture and density of microcracks in comparison with untreated controls.Methods: Trabecular bone from hip fracture patients treated with BP (n = 10) was compared with naïve fractured (n = 14) and non-fractured controls (n = 6). Trabecular cores were synchrotron scanned and micro-CT scanned for microstructural analysis, including quantification of bone volume fraction, microarchitecture and microcracks. The specimens were then mechanically tested in compression.Results: BP bone was 28% lower in strength than untreated hip fracture bone, and 48% lower in strength than non-fractured control bone (4.6 MPa vs 6.4 MPa vs 8.9 MPa). BP-treated bone had 24% more microcracks than naïve fractured bone and 51% more than non-fractured control (8.12/cm2vs 6.55/cm2vs 5.25/cm2). BP and naïve fracture bone exhibited similar trabecular microarchitecture, with significantly lower bone volume fraction and connectivity than non-fractured controls.Conclusion: BP therapy had no detectable mechanical benefit in the specimens examined. Instead, its use was associated with substantially reduced bone strength. This low strength may be due to the greater accumulation of microcracks and a lack of any discernible improvement in bone volume or microarchitecture. This preliminary study suggests that the clinical impact of BP-induced microcrack accumulation may be significant.

Most glenoid implants rely on large centrally located fixation features to avoid perforation of the glenoid vault in its peripheral regions. Upon revision of such components there may not be enough bone left for the reinsertion of an anatomical prosthesis. Multiple press-fit small pegs would allow for less bone resection and strong anchoring in the stiffer and denser peripheral subchondral bone. This study assessed the fixation characteristics, measured as the push-in (Pin) and pull-out (Pout) forces, and spring-back, measured as the elastic displacement immediately after insertion, for five different small press-fitted peg configurations manufactured out of UHMWPE cylinders (5 mm diameter and length). A total of 16 specimens for each configuration were tested in two types of solid bone substitute: Hard (40 PCF, 0.64 g/cm3, worst-case scenario of Pin) and soft (15 PCF, 0.24 g/cm3, worst-case scenario of spring-back and Pout). Two different diametric interference-fits were studied. Geometries with lower stiffness fins (large length to width aspect ratio) were the best performing designs in terms of primary fixation stability. They required the lowest force to fully seat, meaning they are less damaging to the bone during implantation, while providing the highest Pout/Pin ratio, indicating that when implanted they provide the strongest anchoring for the glenoid component. It is highlighted that drilling of chamfered holes could minimize spring-back displacements. These findings are relevant for the design of implants press-fitted pegs because primary fixation has been shown to be an important factor in achieving osseointegration and longevity of secondary fixation.

We present experimental evidence for a quantum phase transition in the easy-axis S = 3/2 anisotropic quasione-dimensional ferromagnet CoCl2 · 2D2O in a transverse field. Elastic neutron scattering shows that the magnetic order parameter vanishes at a transverse critical field μ0Hc = 16.05(4) T, while inelastic neutron scattering shows that the gap in the magnetic excitation spectrum vanishes at the same field value, and reopens for H>Hc. The field dependence of the order parameter and the gap are well described by critical exponents β = 0.45 ± 0.09 and zν close to 1/2, implying that the quantum phase transition in CoCl2 · 2D2O differs significantly from the textbook version of a S = 1/2 Ising chain in a transverse field. We attribute the difference to weak but finite three-dimensionality of the magnetic interactions.

Fragestellung: Integrine (ITGA) sind Zelladhäsionsrezeptoren, die eine Interaktion zwischen der Zelle und ihrer Mikroumgebung ermöglichen. Das ITGA a2b1 besitzt eine besonders hohe Bindungsaffinität gegenüber fibrillärem Kollagen Typ I (KOL I), das mit 95% Hauptbestandteil[zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2016)

Common post-operative problems in shoulder arthroplasty such as glenoid loosening and joint instability may be reduced by improvements in glenoid design, shape, material choice and fixation method. A framework for parametric analysis of different implant fixation configurations was developed in order to efficiently sift through potential glenoid component designs and investigate the influence of design factors such as fixation type, component thickness and peg position, number, diameter and length in a multi-factorial design investigation. The proposed method allowed for simultaneous comparison of the performance of 344 different parametric variations of 10 different reference geometries with large central fixation features or small peripheral pegs, undergoing four different worst-case scenario loading conditions, averaging 64.7 seconds per model. The impact of design parameters were assessed for different factors responsible for post-operative problems in shoulder arthroplasty, such as bone volume preservation, stresses in the implant, central displacement or fixation stability, and the worst performing geometries all relied on conventional central fixation. Of the remaining geometries, four peripheral fixation configurations produced von Mises stresses comfortably below the material's yield strength. We show that the developed method allows for simple, direct, rapid and repeatable comparison of different design features, material choices or fixation methods by analyzing how they influence the bone-implant mechanical environment. The proposed method can provide valuable insight in implant design optimization by screening through multiple potential design modifications at an early design evaluation stage and highlighting the best performing combinations according to the failure mechanism to mitigate. This article is protected by copyright. All rights reserved.

Turbulent rotating convection occurs in many geo- and astrophysical bodies, but it is still far from being well understood. Here, we review some recent findings in this field which were obtained using the JUQUEEN system. We present results revealing that tiny viscous boundary layers, so-called Ekman layers, are much more important in rapidly rotating convection than previously thought. We also discuss evidence for upscale kinetic energy transport generating large-scale, coherent structures in rotating convection. Finally, we briefly discuss the geo- and astrophysically relevant case of convective systems in which the fluid parcels in the deeper parts of the convective region get compressed significantly by the weight of the overlying fluid. We show that in the presence of rotation, such compressibility effects can drive alternating jets similar to those observed on Jupiter and other giant planets.

A 41-year-old man was admitted in circulatory shock of unknown aetiology (systolic pressure 50 mm Hg) and marked reddening of the upper part of the body as well as maculopapular rash over the whole body. After 1500 ml of colloidal solution had been infused the blood pressure rose to a level at which the patient's condition was no longer at risk. He reported having had a similar attack of flushing and circulatory collapse during the last few years, each time after drinking 3-41 of beer. Laboratory tests showed thromboplastin time 56%, partial thromboplastin time 130 s and thrombin time > 180 s. Three hours after admission the coagulation times had further deteriorated, but had become normal within 20 hours. After rest and after a provocation (hot bath) the serum concentrations were: heparin 0.21 U/ml and 0.85 U/ml; histamine 1.9 micrograms/ml and 2.3 micrograms/ml; serotonin 23 micrograms/ml and 38 micrograms/ml. Histological examination of an iliac crest bone marrow biopsy revealed dense collections of mast cells, as seen in systemic mastocytosis. A skin biopsy was diagnostic of urticaria pigmentosa.

Introduction: Integrins mediate cell-matrix interactions of synovial fibroblasts (SF) with cartilage during rheumatoid arthritis (RA) resulting in cartilage degradation and destruction. In this context, integrin α11β1 (ITGA11) is of special interest, because it is mainly expressed in cellular[for full text, please go to the a.m. URL], 43. Kongress der Deutschen Gesellschaft für Rheumatologie (DGRh); 29. Jahrestagung der Deutschen Gesellschaft für Orthopädische Rheumatologie (DGORh); 25. wissenschaftliche Jahrestagung der Gesellschaft für Kinder- und Jugendrheumatologie (GKJR)