408 research outputs found

    Primary stability of cementless threaded acetabular cups at first implantation and in the case of revision regarding micromotions as indicators

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    The primary stability of cementless total hip endoprosthesis is of vital importance for proximate, long-term osteointegration. The extent of micromotions between implant and acetabulum is an indicator of primary stability. Based on this hypothesis, different cementless hip joint endoprosthesis were studied with regard to their micromotions. The primary stability of nine different cementless threaded acetabular cups was studied in an experimental setup with blocks of rigid foam. The micromotions between implant and implant bearing were therefore evaluated under cyclic, sinusoidal exposure. The blocks of polymer foam were prepared according to the Paprosky defect classifications. The micromotions increased with the increasing degree of the defect with all acetabuli tested. Occasionally coefficients of over 200 mu m were measured. From a defect degree of 3b according to Paprosky, the implants could no longer be appropriately placed. The exterior form of the spherical implants tended to exhibit better coefficients than the conical/parabolic implants

    Education and Technology to Empower Teacher in Digital Era

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    Digital learning technologies may enable students to grasp concepts more quickly and fully, to connect theory and application more adeptly, and to engage in learning more readily, while also improving instructional techniques, leveraging instructor time, and facilitating the widespread sharing of knowledge. Digital technologies will enable this in new and better ways and create possibilities beyond the limits of our current imagination. During this presentation, the audience will learn about their own learning styles, the benefits and disadvantages of digital learning and what the future may hold in terms of education and technology, in particular to second language acquisition

    Subconjunctival Loiasis

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    Late Periprosthetic Joint Infection due to Staphylococcus lugdunensis Identified by Matrix-Assisted Laser Desorption/Ionisation Time of Flight Mass Spectrometry: A Case Report and Review of the Literature

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    Staphylococcus lugdunensis, member to the group of coagulase-negative staphylococci, is previously thought to be rarely isolated. Recently other staphylococci have been described, which were supposedly related to S. lugdunensis, such as Staphylococcus pseudolugdunensis and Staphylococcus pettenkoferi. To decrease the rate misidentifications, an accurate identification method, such as matrix-assisted laser desorption ionization time of flight mass spectrometry or molecular methods, should be used. S. lugdunensis is usually associated with severe infections similar to those caused by S. aureus. Moreover, it has been described that skin infections due to S. lugdunensis are severely underreported and could be also underreported in periprosthetic joint infections. Ours is the first case of a late periprosthetic infection of the hip due to S. lugdunensis, identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. A periprosthetic infection due to S. lugdunensis should be treated according to protocols of S. aureus periprosthetic infections, and therefore an accurate species identification is desirable

    How reliable is MRI in diagnosing cartilaginous lesions in patients with first and recurrent lateral patellar dislocations?

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    <p>Abstract</p> <p>Background</p> <p>Lateral dislocation of the patella (LPD) leads to cartilaginous injuries, which have been reported to be associated with retropatellar complaints and the development of patellofemoral osteoarthritis. Therefore, the purpose of this study was to determine the reliability of MRI for cartilage diagnostics after a first and recurrent LPD.</p> <p>Methods</p> <p>After an average of 4.7 days following an acute LPD, 40 patients (21 with first LPDs and 19 with recurrent LPDs) underwent standardized 1.5 Tesla MRI (sagittal T1-TSE, coronal STIR-TSE, transversal fat-suppressed PD-TSE, sagittal fat-suppressed PD-TSE). MRI grading was compared to arthroscopic assessment of the cartilage.</p> <p>Results</p> <p>Sensitivities and positive predictive values for grade 3 and 4 lesions were markedly higher in the patient group with first LPDs compared to the group with recurrent LPDs. Similarly, intra- and inter-observer agreement yielded higher kappa values in patients with first LPDs compared to those with recurrent LPDs. All grade 4 lesions affecting the subchondral bone (osteochondral defects), such as a fissuring or erosion, were correctly assessed on MRI.</p> <p>Conclusions</p> <p>This study demonstrated a comparatively good diagnostic performance for MRI in the evaluation of first and recurrent LPDs, and we therefore recommend MRI for the cartilage assessment after a LPD.</p

    Hierarchical Bayesian model for simulating the mechanical behavior of bare printed circuit boards with fixing

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    A method for probabilistic simulation of a bare printed circuit board fixed with bolted joints based on hierarchical Bayesian updating of a numerical model is presented in this paper. The objective is the determination of parameter uncertainties in a set of nominally identical boards and the propagation of these uncertainties to calculate probability distributions for the behavior of the mechanical system. The numerical model of the system is split into models for the circuit board, the bolts and a contact model that are updated separately

    Integrated analyses of chromatin accessibility and gene expression data for elucidating the transcriptional regulatory mechanisms during early hematopoietic development in mouse

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    RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    NMR Relaxometry Accessing the Relaxation Spectrum in Molecular Glass Formers

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    It is a longstanding question whether universality or specificity characterize the molecular dynamics underlying the glass transition of liquids. In particular, there is an ongoing debate to what degree the shape of dynamical susceptibilities is common to various molecular glass formers. Traditionally, results from dielectric spectroscopy and light scattering have dominated the discussion. Here, we show that nuclear magnetic resonance (NMR), primarily field-cycling relaxometry, has evolved into a valuable method, which provides access to both translational and rotational motions, depending on the probe nucleus. A comparison of ¹H NMR results indicates that translation is more retarded with respect to rotation for liquids with fully established hydrogen-bond networks; however, the effect is not related to the slow Debye process of, for example, monohydroxy alcohols. As for the reorientation dynamics, the NMR susceptibilities of the structural (α) relaxation usually resemble those of light scattering, while the dielectric spectra of especially polar liquids have a different broadening, likely due to contributions from cross correlations between different molecules. Moreover, NMR relaxometry confirms that the excess wing on the high-frequency flank of the α-process is a generic relaxation feature of liquids approaching the glass transition. However, the relevance of this feature generally differs between various methods, possibly because of their different sensitivities to small-amplitude motions. As a major advantage, NMR is isotope specific; hence, it enables selective studies on a particular molecular entity or a particular component of a liquid mixture. Exploiting these possibilities, we show that the characteristic Cole–Davidson shape of the α-relaxation is retained in various ionic liquids and salt solutions, but the width parameter may differ for the components. In contrast, the low-frequency flank of the α-relaxation can be notably broadened for liquids in nanoscopic confinements. This effect also occurs in liquid mixtures with a prominent dynamical disparity in their components
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