A hierarchical frailty model applied to two-generation melanoma data

We present a hierarchical frailty model based on distributions derived from non-negative Lévy processes. The model may be applied to data with several levels of dependence, such as family data or other general clusters, and is an alternative to additive frailty models. We present several parametric examples of the model, and properties such as expected values, variance and covariance. The model is applied to a case-cohort sample of age at onset for melanoma from the Swedish Multi-Generation Register, organized in nuclear families of parents and one or two children. We compare the genetic component of the total frailty variance to the common environmental term, and estimate the effect of birth cohort and gender. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

Magnetic helicity fluxes in an alpha-squared dynamo embedded in a halo

We present the results of simulations of forced turbulence in a slab where the mean kinetic helicity has a maximum near the mid-plane, generating gradients of magnetic helicity of both large and small-scale fields. We also study systems that have poorly conducting buffer zones away from the midplane in order to assess the effects of boundaries. The dynamical alpha quenching phenomenology requires that the magnetic helicity in the small-scale fields approaches a nearly static, gauge independent state. To stress-test this steady state condition we choose a system with a uniform sign of kinetic helicity, so that the total magnetic helicity can reach a steady state value only through fluxes through the boundary, which are themselves suppressed by the velocity boundary conditions. Even with such a set up, the small-scale magnetic helicity is found to reach a steady state. In agreement with earlier work, the magnetic helicity fluxes of small-scale fields are found to be turbulently diffusive. By comparing results with and without halos, we show that artificial constraints on magnetic helicity at the boundary do not have a significant impact on the evolution of the magnetic helicity, except that "softer" (halo) boundary conditions give a lower energy of the saturated mean magnetic field.Comment: 12 pages, 5 figures, submitted to GAF

Development and Reliability of the OMERACT Thumb Base Osteoarthritis Magnetic Resonance Imaging Scoring System

Objective: To develop the Outcome Measures in Rheumatology (OMERACT) thumb base osteoarthritis (OA) magnetic resonance imaging (MRI) scoring system (TOMS) for the assessment of inflammatory and structural abnormalities in this hand OA subset, and test its cross-sectional reliability. Methods: Included features and their scaling were agreed upon by members of the OMERACT MRI Task Force using the Hand OA MRI scoring system as a template. A reliability exercise was performed in which 3 readers participated, using a preliminary atlas with examples to facilitate reading. Each reader independently scored a set of 20 MRI (coronal and axial T1- and T2-weighted fat-suppressed images, of which 5 included T1-weighted fat-suppressed post-Gadolinium images). Intra- and interreader reliability were assessed using ICC, percentage exact agreement (PEA), and percentage close agreement (PCA). Results: The TOMS assessed the first carpometacarpal (CMC-1) and scaphotrapeziotrapezoid (STT) joints for synovitis, subchondral bone defects (including erosions, cysts, and bone attrition), osteophytes, cartilage, and bone marrow lesions on a 0–3 scale (normal to severe). Subluxation was evaluated only in the CMC-1 joint (absent/present). Reliability of scoring for both joints was comparable. Interreader ICC were good for all features (0.77–0.99 and 0.74-0.96 for CMC-1 and STT joints, respectively). Intrareader reliability analyses gave similar results. PCA was ≥ 65% for all features. PEA was low to moderate, with better performance for subchondral bone defects, subluxation, and bone marrow lesions. Conclusion: A thumb base OA MRI scoring system has been developed. The OMERACT TOMS demonstrated good intrareader and interreader reliability. Longitudinal studies are warranted to investigate reliability of change scores and responsiveness

Atlas for the OMERACT thumb base osteoarthritis MRI scoring system (TOMS)

This paper presents an atlas for the Outcome Measures in Rheumatology Clinical Trials (OMERACT) thumb base osteoarthritis MRI scoring system (TOMS). The atlas includes reference images of each grade of each feature that is assessed in TOMS (synovitis grade 0–3, subchondral bone defects grade 0–3, osteophytes grade 0–3, cartilage assessment grade 0–3, subluxation and bone marrow lesions grade 0–3) in the first carpometacarpal and scapho-trapezio-trapezoid joint. The presented reference images can be used to guide scoring of thumb base MRIs in patients with hand osteoarthritis according to the OMERACT TOMS

Diet matters, particularly in pregnancy – Results from MoBa studies of maternal diet and pregnancy outcomes

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Awareness that maternal diet may influence the outcome of pregnancy as well as the long-term health of mother and child has increased in recent years. A new food frequency questionnaire (FFQ) was developed and validated specifically for the Norwegian Mother and Child Cohort Study (MoBa). The MoBa FFQ is a semi-quantitative tool which covers the average intake of food, beverages and dietary supplements during the first 4 to 5 months of pregnancy. It includes questions about intakes of 255 foods and dishes and was used from 2002 onwards. Data assessed by the MoBa FFQ is available for 87,700 pregnancies. Numerous sub-studies have examined associations between dietary factors and health outcomes in MoBa. The aim of this paper is to summarize the results from 19 studies of maternal diet and pregnancy outcomes, which is the complete collection of studies based on the MoBa FFQ and published before September 2014. The overall research question is whether maternal diet – from single substances to dietary patterns – matters for pregnancy outcome. The pregnancy outcomes studied till now include birth size measures, infants being small and large for gestational age, pregnancy duration, preterm delivery, preeclampsia, as well as maternal gestational weight gain and postpartum weight retention. As a whole, the results from these studies corroborate that the current dietary recommendations to pregnant women are sound and that maternal diet during pregnancy is likely to contribute to reduce the risk of pregnancy complications including preterm birth, preeclampsia, and reduced foetal growth. The results provide supporting evidence for recommending pregnant women to consume vegetables, fruit, whole grain, fish, dairy, and water regularly and lower the intake of sugar sweetened beverages, processed meat products and salty snacks. The results showing negative impact of even low levels of environmental contaminants support the precautionary advice on consumption of foods containing these. New findings are that particularly lean fish explained the positive association between seafood intake and foetal growth, and the indications of a protective effect of probiotic and antimicrobial foods on pregnancy outcomes. This points to the importance of diet composition for a healthy gut flora and the body’s immune response. Although these studies are observational and cannot infer causality, the results identify diet as an important modifiable lifestyle factor, suggesting that healthy eating, defined as following the official recommendations, is particularly important in pregnanc

Complex chloroplast RNA metabolism: just debugging the genetic programme?

<p>Abstract</p> <p>Background</p> <p>The gene expression system of chloroplasts is far more complex than that of their cyanobacterial progenitor. This gain in complexity affects in particular RNA metabolism, specifically the transcription and maturation of RNA. Mature chloroplast RNA is generated by a plethora of nuclear-encoded proteins acquired or recruited during plant evolution, comprising additional RNA polymerases and sigma factors, and sequence-specific RNA maturation factors promoting RNA splicing, editing, end formation and translatability. Despite years of intensive research, we still lack a comprehensive explanation for this complexity.</p> <p>Results</p> <p>We inspected the available literature and genome databases for information on components of RNA metabolism in land plant chloroplasts. In particular, new inventions of chloroplast-specific mechanisms and the expansion of some gene/protein families detected in land plants lead us to suggest that the primary function of the additional nuclear-encoded components found in chloroplasts is the transgenomic suppression of point mutations, fixation of which occurred due to an enhanced genetic drift exhibited by chloroplast genomes. We further speculate that a fast evolution of transgenomic suppressors occurred after the water-to-land transition of plants.</p> <p>Conclusion</p> <p>Our inspections indicate that several chloroplast-specific mechanisms evolved in land plants to remedy point mutations that occurred after the water-to-land transition. Thus, the complexity of chloroplast gene expression evolved to guarantee the functionality of chloroplast genetic information and may not, with some exceptions, be involved in regulatory functions.</p

DYNAMIC FRAGMENTATION OF C-60 IONS

The distribution of fragments resulting from collisions between 50-200-keV C60+ ions and H-2 and He is found to follow approximately a simple power law I(m) = cp(m), where p is a constant depending on both energy and target gas, and m is the number of missing &quot;pairs&quot; of carbon atoms. Based on this observation, a new dynamical fragmentation model involving the ratio of two characteristic times is proposed. In collisions by 300-keV C60(2+) ions, the singly charged products are distributed quite differently, which implies the first evidence of the presence of charge-separation reactions

Reliability and Agreement of Proton Density-weighted vs. Gadolinium-enhanced T1-weighted MRI in Hand Osteoarthritis. An OMERACT MRI Special Interest Group reliability exercise

Objectives: To compare reliabilities of assessing synovitis in hand osteoarthritis (OA) using Magnetic Resonance Imaging (MRI) with/without gadolinium (Gd). Methods: Three readers scored synovitis on non-enhanced two-dimensional (2D) proton density (PD)weighted MRI and Gd-enhanced (3D) MRI of hand joints in 20 patients. Inter-reader reliabilities were examined. Results: Reliability was good for Gd-enhanced MRI, but poor for non-enhanced PD-weighted MRI (intraclass correlation coefficient 0.83 and 0.21, respectively). Agreement between the two sequences was poor (weighted kappa 0.18). Conclusion: Gd-enhanced MRI was more reliable than PD-weighted MRI for assessing synovitis. Gd-enhancement, but also resolution and tissue contrast, might have contributed to this. (c) 2021 Elsevier Inc. All rights reserved.Pathophysiology and treatment of rheumatic disease