Temperature Dependent Neutron Scattering Sections for Polyethylene

This note presents neutron scattering cross sections for polyethylene at 296 K, 77 K and 4 K derived from a new scattering kernel for neutron scattering off of hydrogen in polyethylene. The kernel was developed in ENDF-6 format as a set of S(alpha,beta) tables using the LEAPR module of the NJOY94 code package. The polyethylene density of states (from 0 to sub eV) adopted to derive the new kernel is presented. We compare our calculated room temperature total scattering cross sections and double differential cross sections at 232 meV at various angles with the available experimental data (at room temperature), and then extrapolate the calculations to lower temperatures (77K and 4K). The new temperature dependent scattering kernel gives a good quantitative fit to the available room temperature data and has a temperature dependence that is qualitatively consistent with thermodynamics.Comment: 6 page

Trowelable ablative coating composition and method of use

A trowelable ablative coating composition is disclosed. The composition comprises an epoxy resin, an amide curing agent, glass microspheres and ground cork. A method for protecting a substrate is also disclosed. The method comprises applying the trowelable ablative coating discussed above to a substrate and curing the coating composition

Fabric Parameters and Pesticide Characteristics That Impact on Dermal Exposure of Applicators

Fabric functional finish and formulation of pesticides are factors that contribute to pesticide wicking, wetting, and penetration. Fluorocarbon soil-repellent finishes inhibit contamination of the fabric and of sentinel pads. An undergarment layer offers better protection than does a single layer. Spun-bonded olefin offers protection of the same magnitude as soil-repellent finishes. Methyl parathion residues after laundering were similar for the unfinished fabric, the durable-press finished fabric, and the soil-repellent finished fabric, but the initial contamination of the soil-repellent finished fabric was only 20~ of that of the other two fabrics

Structural associations of symptomatic knee osteoarthritis

Objective Structural changes of osteoarthritis (OA) may occur in the absence of pain. In this study, we aimed to identify histopathologic features that are associated with symptomatic knee OA. Methods Medial tibial plateaus and synovium samples were obtained at the time of total knee replacement (TKR) surgery for OA (advanced OA group) or were obtained postmortem from subjects who had not sought medical attention for knee pain during the last year of life (non-OA control group). To identify features of OA, we compared the patients with advanced OA with the age-matched non-OA controls (n = 26 per group). To identify OA features associated with symptoms, we compared two additional groups of subjects who were matched for severity of chondropathy (n = 29 per group): patients undergoing TKR for symptomatic OA (symptomatic chondropathy group) and postmortem subjects with similar severity of chondropathy who were asymptomatic during the last year of life (asymptomatic chondropathy group). The histologic features of the samples were graded, and immunoreactivities for macrophages (CD68) and nerve growth factor (NGF) in the synovium were quantified. The cellular localization of synovial NGF was determined by double immunofluorescence analysis. Results Advanced OA cases displayed more severe changes in the synovium (synovitis, increased synovial NGF, and CD68-immunoreactive macrophages) and cartilage (loss of cartilage surface integrity, loss of proteoglycan, tidemark breaching, and alterations in chondrocyte morphology) than did the non-OA controls. Synovial NGF was localized predominantly to fibroblasts and to some macrophages. The symptomatic chondropathy group displayed greater levels of synovitis, synovial NGF, and loss of cartilage integrity, in addition to alterations in chondrocyte morphology, than did the asymptomatic chondropathy group (P < 0.05 for each comparison). Conclusion Synovitis, increased synovial NGF, alterations in chondrocyte morphology, and loss of cartilage integrity are features of knee OA that may be associated with symptoms

Behaviour and the safety of older people on stairs

Behaviour and the safety of older people on stair

A simple method to derive speed for the endurance shuttle walk test

Background: The original method for determining endurance shuttle walk test (ESWT) speed involves components that are time consuming for clinicians. We sought to determine: (i) whether components described in the original method for determining ESWT speed held true and; (ii) the agreement between speeds derived using the original method and that equivalent to 85% of the peak speed achieved during the incremental shuttle walk test (ISWT). Methods: Patients with chronic obstructive pulmonary disease (COPD) performed two ISWTs and one ESWT on separate days, wearing a calibrated portable gas analysis unit. A retrospective analysis of these data allowed us to determine whether: (i) the peak rate of oxygen uptake (VO2peak) can be accurately estimated from the incremental shuttle walk distance (ISWD) and; (ii) ESWTs performed at a speed derived using the original method elicited 85% of VO2peak. Agreement between walks speeds was determined using Bland–Altman analysis. Results: Twenty-two participants (FEV1 48 ± 13% predicted, age 66 ± 8 yr) completed the study. The VO2peak estimated from the ISWD was less than that measured during the ISWT (mean difference −4.4; 95% confidence interval (CI), −6.0 to −2.9 ml• kg−1•min−1). The ESWT and ISWT elicited similar VO2peak (mean difference −0.2; 95% CI, −1.5 to 1.2 ml•kg−1•min−1). The mean difference (±limits of agreement) between ESWT speeds was 0.15 (±0.34) km•h−1. Conclusions: Components of the original method for determining the ESWT speed did not hold true in our sample. ESWT speed can be derived by calculating 85% of the peak speed achieved during the ISWT

Safety of older people on stairs : behavioural factors

Falling on steps and stairs in the home is a serious problem for older people aged 65 and over, both in terms of the high frequency with which these accidents occur and their consequences. Although previous research has increased knowledge of personal and environmental factors involved in falls on stairs, behavioural aspects have received less attention. The aini of this investigation, therefore, was to improve understanding of how older people keep and use their stairs, and to assess the iniplications for stair safety. Interviews were conducted with 157 older people, aged between 65-96 years, in their own homes. Using a conibination of open and closed questions, participants were asked about their behaviour on and around thc stairs, awareness of safety factors and any history of falling on stairs. During each visit, information was collected about the stairs in the home including design and repair of stair coverings, number of handrails and thcir condition, objects on and around the stairs, lighting, and position of windows. Standard mthropometric dimensions of interviewees were recorded, along with other measurements including grip strength, ability to get up from a stool without using hands, and measures of visual acuity and depth perception

Dielectric Screening in a Spherical Cavity

In this work we examine the electrostatic screening potential due to a point charge located off-centre in a spherical dielectric cavity. This potential is expanded for the case in which the dielectric constant $\epsilon$ is large, several methods of finding the terms in the expansion are investigated, and closed-form expressions are found through third order in $\epsilon$ along with error bounds. Finally, possible uses of these expressions in molecular dynamics simulations of isolated charged molecules is discussed.Comment: 15 Pages, 5 Figures, To be submitted to J. Phys. A. Uses iopart.cl

Middle Jurassic fossils document an early stage in salamander evolution

Salamanders are an important group of living amphibians and model organisms for understanding locomotion, development, regeneration, feeding, and toxicity in tetrapods. However, their origin and early radiation remain poorly understood, with early fossil stem-salamanders so far represented by larval or incompletely known taxa. This poor record also limits understanding of the origin of Lissamphibia (i.e., frogs, salamanders, and caecilians). We report fossils from the Middle Jurassic of Scotland representing almost the entire skeleton of the enigmatic stem-salamander Marmorerpeton. We use computed tomography to visualize high-resolution three-dimensional anatomy, describing morphologies that were poorly characterized in early salamanders, including the braincase, scapulocoracoid, and lower jaw. We use these data in the context of a phylogenetic analysis intended to resolve the relationships of early and stem-salamanders, including representation of important outgroups alongside data from high-resolution imaging of extant species. Marmorerpeton is united with Karaurus, Kokartus, and others from the Middle Jurassic–Lower Cretaceous of Asia, providing evidence for an early radiation of robustly built neotenous stem-salamanders. These taxa display morphological specializations similar to the extant cryptobranchid “giant” salamanders. Our analysis also demonstrates stem-group affinities for a larger sample of Jurassic species than previously recognized, highlighting an unappreciated diversity of stem-salamanders and cautioning against the use of single species (e.g., Karaurus) as exemplars for stem-salamander anatomy. These phylogenetic findings, combined with knowledge of the near-complete skeletal anatomy of Mamorerpeton, advance our understanding of evolutionary changes on the salamander stem-lineage and provide important data on early salamanders and the origins of Batrachia and Lissamphibia

Molecular expression patterns in the synovium and their association with advanced symptomatic knee osteoarthritis

Objective: Osteoarthritis (OA) is a major source of knee pain. Mechanisms of OA knee pain are incompletely understood but include synovial pathology. We aimed to identify molecular expression patterns in the synovium associated with symptomatic knee OA.Design: Snap frozen synovia were from people undergoing total knee replacement (TKR) for advanced OA, or from post-mortem (PM) cases who had not sought help for knee pain. Associations with OA symptoms were determined using discovery and validation samples, each comprising TKR and post mortem (PM) cases matched for chondropathy (Symptomatic or Asymptomatic Chondropathy). Associations with OA were determined by comparing age matched TKR and PM control cases. Real-time quantitative PCR for 96 genes involved in inflammation and nerve sensitisation used TaqMan® Array Cards in discovery and validation samples, and protein expression for replicated genes was quantified using Luminex bead assay.Results: Eight genes were differentially expressed between asymptomatic and symptomatic chondropathy cases and replicated between discovery and validation samples (P3-fold change). Of these, matrix metalloprotease (MMP)-1 was also increased whereas interleukin-1 receptor 1 (IL1R1) and vascular endothelial growth factor (VEGF) were decreased at the protein level in the synovium of symptomatic compared to asymptomatic chondropathy cases. MMP1 protein expression was also increased in OA compared to PM controls.Conclusion: Associations of symptomatic OA may suggest roles of MMP1 expression and IL1R1 and VEGF pathways in OA pain. Better understanding of which inflammation-associated molecules mediate OA pain should inform refinement of existing therapies and development of new treatments