458 research outputs found
Anomaly-free dark matter models with one-loop neutrino masses and a gauged U(1) symmetry
We systematically study and classify scotogenic models with a local U(1)
gauge symmetry. These models give rise to radiative neutrino masses and a
stable dark matter candidate, but avoid the theoretical problems of global and
discrete symmetries. We restrict the dark sector particle content to up to four
scalar or fermionic SU(2) singlets, doublets or triplets and use theoretical
arguments based on anomaly freedom, Lorentz and gauge symmetry to find all
possible charge assignments of these particles. The U(1) symmetry can be broken
by a new Higgs boson to a residual discrete symmetry, that still stabilizes the
dark matter candidate. We list the particle content and charge assignments of
all non-equivalent models. Specific examples in our class of models that have
been studied previously in the literature are the U(1) scotogenic and
singlet-triplet scalar models breaking to . We also briefly discuss the
new phenomenological aspects of our model arising from the presence of a new
massless dark photon or massive boson as well as the additional Higgs
boson.Comment: 23 pages, 1 figure, 5 table
Towards sex-specific osteoarthritis risk models: evaluation of risk factors for knee osteoarthritis in males and females
Objectives The aim of this study was to identify sex-specific prevalence and strength of risk factors for the incidence of radiographic knee OA (incRKOA). Methods Our study population consisted of 10 958 Rotterdam Study participants free of knee OA in one or both knees at baseline. One thousand and sixty-four participants developed RKOA after a median follow-up time of 9.6 years. We estimated the association between each available risk factor and incRKOA using sex stratified multivariate regression models with generalized estimating equations. Subsequently, we statistically tested sex differences between risk estimates and calculated the population attributable fractions (PAFs) for modifiable risk factors. Results The prevalence of the investigated risk factors was, in general, higher in women compared with men, except that alcohol intake and smoking were higher in men and high BMI showed equal prevalence. We found significantly different risk estimates between men and women: high level of physical activity [relative risk (RR) 1.76 (95% CI: 1.29–2.40)] or a Kellgren and Lawrence score 1 at baseline [RR 5.48 (95% CI: 4.51–6.65)] was higher in men. Among borderline significantly different risk estimates was BMI ≥27, associated with higher risk for incRKOA in women [RR 2.00 (95% CI: 1.74–2.31)]. The PAF for higher BMI was 25.6% in women and 19.3% in men. Conclusion We found sex-specific differences in both presence and relative risk of several risk factors for incRKOA. Especially BMI, a modifiable risk factor, impacts women more strongly than men. These risk factors can be used in the development of personalized prevention strategies and in building sex-specific prediction tools to identify high risk profile patients
Bone Union Assessment with Computed Tomography (CT) and Statistical Associations with Mechanical or Histological Testing:A Systematic Review of Animal Studies
Objective and accurate assessment of bone union after a fracture, arthrodesis, or osteotomy is relevant for scientific and clinical purposes. Bone union is most accurately imaged with computed tomography (CT), but no consensus exists about objective assessment of bone union from CT images. It is unclear which CT-generated parameters are most suitable for bone union assessment. The aim of this review of animal studies is to find which CT-generated parameters are associated most strongly with actual bone union. Scientific databases were systematically searched. Eligible studies were studies that (1) were animal studies, (2) created a fracture, (3) assessed bone union with CT, (4) performed mechanical or histological testing as measure of actual bone union, and (5) associated CT-generated outcomes to mechanical or histological testing results. Two authors selected eligible studies and performed risk of bias assessment with QUADAS-2 tool. From 2567 studies that were screened, thirteen studies were included. Most common CT parameters that were investigated were bone mineral density, bone volume, and total callus volume. Studies showed conflicting results concerning the associations of these parameters with actual bone union. CT-assessed torsional rigidity (assessed by three studies) and callus density (assessed by two studies) showed best results. The studies investigating these two parameters reported moderate to strong associations with actual bone union. CT-assessed torsional rigidity and callus density seem the most promising parameters to represent actual bone union after a fracture, arthrodesis, or osteotomy. Prospero trial registration number: CRD4202016473
Outcome Expectations of Total Knee Arthroplasty Patients: The Influence of Demographic Factors, Pain, Personality Traits, Physical and Psychological Status
Unfulfilled preoperative expectations have a strong influence on the outcome after total knee arthroplasty (TKA). More insight into determinants of the level of expectations is useful in identifying patients at risk for having expectations of the treatment result that are too high or too low. This information can be used in optimizing preoperative expectation management. The aim of the current study was to analyze to what extent preoperative outcome expectations of TKA patients are affected by psychological factors, demographic factors, pain, physical function, and general health status. We performed a cross-sectional analysis of 204 patients with symptomatic and radiographic knee osteoarthritis (OA), scheduled for primary TKA. Outcome expectations were measured using the hospital for special surgery knee replacement expectations survey. Independent variables included were age, sex, body mass index, and patient-reported outcome measures for pain, physical function, quality of life, anxiety, depression, catastrophizing, optimism, and pessimism. Multiple linear regression analyses were used to evaluate associations between these variables and preoperative outcome expectations. Female sex, higher age, higher depression score, and duration of complaints > 50 months showed to be significant predictors of lower expectations for the treatment outcome after TKA. Baseline pain and function scores were not related to the level of preoperative expectations. The present study aids in identifying patients at risk for having either too high or too low expectations. This knowledge can be utilized in individualized expectation management interventions
Efficacy of foot orthoses for the treatment of plantar heel pain:a systematic review and meta-analysis
BackgroundPlantar heel pain (PHP) is common. Foot orthoses are often applied as treatment for PHP, even though there is little evidence to support this.ObjectiveTo investigate the effects of different orthoses on pain, function and self-reported recovery in patients with PHP and compare them with other conservative interventions.DesignSystematic review and meta-analysis.Data sourcesA systematic literature search was conducted in MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, CINAHL and Google Scholar up to January 2017.Eligibility criteria for selecting studiesRandomised controlled trials comparing foot orthoses with a control (defined as no intervention, sham or other type of conservative treatment) reporting on pain, function or self-reported recovery in patients with PHP.ResultsTwenty studies investigating eight different types of foot orthoses were included in the review. Most studies were of high quality. Pooled data from six studies showed no difference between prefabricated orthoses and sham orthoses for pain at short term (mean difference (MD) of 0.26 (95% CI −0.09 to 0.60)). No difference was found between sham orthoses and custom orthoses for pain at short term (MD 0.22 (95% CI −0.05 to 0.50)), nor was there a difference between prefabricated orthoses and custom orthoses for pain at short term (MD 0.03 (95% CI −0.15 to 0.22)). For the majority of other interventions, no significant differences were found.ConclusionsFoot orthoses are not superior for improving pain and function compared with sham or other conservative treatment in patients with PHP.PROSPERO registration numberCRD42015029659.</jats:sec
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