The Olympia anatomic polished cemented stem is associated with a high survivorship, excellent hip-specific functional outcome, and high satisfaction levels:follow-up of 239 consecutive patients beyond 15 years

Introduction: The Olympia femoral stem is a stainless steel, anatomically shaped, polished and three-dimensionally tapered implant designed for use in cemented total hip arthroplasty (THA). The primary aim of this study was to determine the long-term survivorship, radiographic outcome, and patient-reported outcome measures (PROMs) of the Olympia stem. Patients and methods: Between May 2003 and December 2005, 239 patients (264 THAs) underwent a THA with an Olympia stem in our institution. Patient-reported outcome measures were assessed using the Oxford Hip Score (OHS), EuroQol-5 dimensions (EQ-5D) score, and patient satisfaction at mean 10 years following THA. Patient records and radiographs were then reviewed at a mean of 16.5 years (SD 0.7, 15.3–17.8) following THA to identify occurrence of complications or revision surgery for any cause following surgery. Radiographs were assessed for lucent lines and lysis according to Gruen’s zones Results: Mean patient age at surgery was 68.0 years (SD 10.9, 31–93 years). There were 156 women (65%, 176 THAs). Osteoarthritis was the indication for THA in 204 patients (85%). All cause stem survivorship at 10 years was 99.2% (95% confidence interval [CI], 97.9%–100%) and at 15 years was 97.5% (94.6%–100%). The 15-year stem survival for aseptic loosening was 100%. Analysis of all-cause THA failure demonstrated a survivorship of 98.5% (96.3%–100%) at 10 years and 95.9% (92.4%–99.4%) at 15 years. There were 9 THAs with non-progressive lucent lines in a single Gruen zone and 3 had lines in two zones, and no patient demonstrated signs for lysis. At a mean of 10-year (SD 0.8, 8.7–11.3) follow-up, mean OHS was 39 (SD 10.3, range 7–48) and 94% of patients reported being very satisfied or satisfied with their THA. Conclusions: The Olympia stem demonstrated excellent 10-year PROMs and very high rates of stem survivorship at final follow-up beyond 15 years

ИЗВЛЕЧЕНИЕ И РАЗДЕЛЕНИЕ НЕМАГНИТНЫХ ЭЛЕКТРОПРОВОДНЫХ МАТЕРИАЛОВ В МАГНИТНОМ ПОЛЕ

Розглянуто метод вилучення та розподілу немагнітних сипучих матеріалів по електропровідності змінному магнітному полі який отримав назву електродинамічна сепарація. Відмічено галузі використання методу. Запропоновано класифікацію відомих засобів електродинамічної сепарації, що ґрунтуються на вилученні ряду ознак.Розглянуто метод вилучення та розподілу немагнітних сипучих матеріалів по електропровідності змінному магнітному полі який отримав назву електродинамічна сепарація. Відмічено галузі використання методу. Запропоновано класифікацію відомих засобів електродинамічної сепарації, що ґрунтуються на вилученні ряду ознак

In human autoimmunity, a substantial component of the B cell repertoire consists of polyclonal, barely mutated IgG+ve B cells

B cells are critical for promoting autoimmunity and the success of B cell depletion therapy in rheumatoid arthritis (RA) confirms their importance in driving chronic inflammation. Whilst disease specific autoantibodies are useful diagnostically, our understanding of the pathogenic B cell repertoire remains unclear. Defining it would lead to novel insights and curative treatments. To address this, we have undertaken the largest study to date of over 150 RA patients, utilizing next generation sequencing (NGS) to analyze up to 200,000 BCR sequences per patient. The full-length antigen-binding variable region of the heavy chain (IgGHV) of the IgG B cell receptor (BCR) were sequenced. Surprisingly, RA patients do not express particular clonal expansions of B cells at diagnosis. Rather they express a polyclonal IgG repertoire with a significant increase in BCRs that have barely mutated away from the germline sequence. This pattern remains even after commencing disease modifying therapy. These hypomutated BCRs are expressed by TNF-alpha secreting IgG+veCD27−ve B cells, that are expanded in RA peripheral blood and enriched in the rheumatoid synovium. A similar B cell repertoire is expressed by patients with Sjögren's syndrome. A rate limiting step in the initiation of autoimmunity is the activation of B cells and this data reveals that a sizeable component of the human autoimmune B cell repertoire consists of polyclonal, hypomutated IgG+ve B cells, that may play a critical role in driving chronic inflammation

Using geographically weighted regression to explore the spatially heterogeneous spread of bovine tuberculosis in England and Wales

An understanding of the factors that affect the spread of endemic bovine tuberculosis (bTB) is critical for the development of measures to stop and reverse this spread. Analyses of spatial data need to account for the inherent spatial heterogeneity within the data, or else spatial autocorrelation can lead to an overestimate of the significance of variables. This study used three methods of analysis—least-squares linear regression with a spatial autocorrelation term, geographically weighted regression (GWR) and boosted regression tree (BRT) analysis—to identify the factors that influence the spread of endemic bTB at a local level in England and Wales. The linear regression and GWR methods demonstrated the importance of accounting for spatial differences in risk factors for bTB, and showed some consistency in the identification of certain factors related to flooding, disease history and the presence of multiple genotypes of bTB. This is the first attempt to explore the factors associated with the spread of endemic bTB in England and Wales using GWR. This technique improves on least-squares linear regression approaches by identifying regional differences in the factors associated with bTB spread. However, interpretation of these complex regional differences is difficult and the approach does not lend itself to predictive models which are likely to be of more value to policy makers. Methods such as BRT may be more suited to such a task. Here we have demonstrated that GWR and BRT can produce comparable outputs

Heteroskedasticity testing through a comparison of Wald statistics

This paper shows that a test for heteroskedasticity within the context of classical linear regression can be based on the difference between Wald statistics in heteroskedasticity-robust and nonrobust forms. The test is asymptotically distributed under the null hypothesis of homoskedasticity as chi-squared with one degree of freedom. The power of the test is sensitive to the choice of parametric restriction used by the Wald statistics, so the supremum of a range of individual test statistics is proposed. Two versions of a supremum-based test are considered: the first version does not have a known asymptotic null distribution, so the bootstrap is employed to approximate its empirical distribution. The second version has a known asymptotic distribution and, in some cases, is asymptotically pivotal under the null. A simulation study illustrates the use and finite-sample performance of both versions of the test. In this study, the bootstrap is found to provide better size control than asymptotic critical values, namely with heavy-tailed, asymmetric distributions of the covariates. In addition, the use of well-known modifications of the heteroskedasticity consistent covariance matrix estimator of OLS coefficients is also found to benefit the tests’ overall behaviour.info:eu-repo/semantics/publishedVersio