Evaluation Of Football Shoulder Pads

The development of sports protective equipment has been largely the result of trial and error and, with the exception of foot and head protective devices, has not involved the research process. Claims related to football shoulder pad innovations have not typically been supported by relevant objective data. The purpose of this study was to develop procedures and instrumentation for comparison of the effectiveness of shoulder pads. The most important criterion for protective effectiveness was considered to be the prevention of high peak pressures on body parts and tissues underneath the pads. Phase I of the study was designed to determine player perceptions of high-pressure sites following performance of drills on the field using a variety of pads. Phase II involved the development of instrumentation and procedures to directly measure pressure on sites identified in phase I during a controlled blocking drill simulating field conditions. Pressure measurements were taken using twelve pressure sensing resistors (0.6 mm thick and 12 mm in diameter) attached to selected sites underneath the pads. Signal conditioning circuity was developed to provide output from these transducers proportional to pressure. The output was routed to a digital computer via an analog-todigital interface board for subsequent analysis. The measurement system was used to evaluate six sets of shoulder pads representing the use of conventional, closed-cell foam and the use of open-cell foam (one and three layers) with an air management system. Four experienced subjects used each set of pads to hit a blocking dummy several times. Results were consistent with subjects' perceptions of areas of greatest pressure, indicating that: 1) greatest peak forces for all pads were received on the portion of the superior portion of the deltoid, acromion, and superior portion of the trapezius; and 2) pads using open-cell foam with an air management system were superior to pads using closed-cell foam in preventing high peak pressures. This study was partially supported by the Kansas State University Research Foundation

Understanding the Challenges of Reducing Cancer in Appalachia: Addressing a Place-Based Health Disparity Population

The Appalachian region of the United States has long been recognized for its poor economic and social indicators. Only during the past decade have multi-state data become more accessible to describe the regions’ poor health status and resulting outcomes. A recent community-based participatory study engaged rural Appalachians to describe “what makes Appalachia different?” from other geographic areas and cultural groups in the United States and identify those characteristics that influence the region’s health. This article summarizes the community interpretation of these findings

Effect of Ordering on Spinodal Decomposition of Liquid-Crystal/Polymer Mixtures

Partially phase-separated liquid-crystal/polymer dispersions display highly fibrillar domain morphologies that are dramatically different from the typical structures found in isotropic mixtures. To explain this, we numerically explore the coupling between phase ordering and phase separation kinetics in model two-dimensional fluid mixtures phase separating into a nematic phase, rich in liquid crystal, coexisting with an isotropic phase, rich in polymer. We find that phase ordering can lead to fibrillar networks of the minority polymer-rich phase

High-resolution computed tomography reconstructions of invertebrate burrow systems

The architecture of biogenic structures can be highly influential in determining species contributions to major soil and sediment processes, but detailed 3-D characterisations are rare and descriptors of form and complexity are lacking. Here we provide replicate high-resolution micro-focus computed tomography (μ-CT) data for the complete burrow systems of three co-occurring, but functionally contrasting, sediment-dwelling inter-tidal invertebrates assembled alone, and in combination, in representative model aquaria. These data (≤2,000 raw image slices aquarium−1, isotropic voxel resolution, 81 μm) provide reference models that can be used for the development of novel structural analysis routines that will be of value within the fields of ecology, pedology, geomorphology, palaeobiology, ichnology and mechanical engineering. We also envisage opportunity for those investigating transport networks, vascular systems, plant rooting systems, neuron connectivity patterns, or those developing image analysis or statistics related to pattern or shape recognition. The dataset will allow investigators to develop or test novel methodology and ideas without the need to generate a complete three-dimensional computation of exemplar architecture

Scintillation proximity assay for measurement of RNA methylation

Methylation of RNA by methyltransferases is a phylogenetically ubiquitous post-transcriptional modification that occurs most extensively in transfer RNA (tRNA) and ribosomal RNA (rRNA). Biochemical characterization of RNA methyltransferase enzymes and their methylated product RNA or RNA–protein complexes is usually done by measuring the incorporation of radiolabeled methyl groups into the product over time. This has traditionally required the separation of radiolabeled product from radiolabeled methyl donor through a filter binding assay. We have adapted and optimized a scintillation proximity assay (SPA) to replace the more costly, wasteful and cumbersome filter binding assay and demonstrate its utility in studies of three distinct methyltransferases, RmtA, KsgA and ErmC’. In vitro, RmtA and KsgA methylate different bases in 16S rRNA in 30S ribosomal particles, while ErmC’ most efficiently methylates protein-depleted or protein-free 23S rRNA. This assay does not utilize engineered affinity tags that are often required in SPA, and is capable of detecting either radiolabeled RNA or RNA–protein complex. We show that this method is suitable for quantitating extent of RNA methylation or active RNA methyltransferase, and for testing RNA-methyltransferase inhibitors. This assay can be carried out with techniques routinely used in a typical biochemistry laboratory or could be easily adapted for a high throughput screening format

Non-isothermal model for the direct isotropic/smectic-A liquid crystalline transition

An extension to a high-order model for the direct isotropic/smectic-A liquid crystalline phase transition was derived to take into account thermal effects including anisotropic thermal diffusion and latent heat of phase-ordering. Multi-scale multi-transport simulations of the non-isothermal model were compared to isothermal simulation, showing that the presented model extension corrects the standard Landau-de Gennes prediction from constant growth to diffusion-limited growth, under shallow quench/undercooling conditions. Non-isothermal simulations, where meta-stable nematic pre-ordering precedes smectic-A growth, were also conducted and novel non-monotonic phase-transformation kinetics observed.Comment: First revision: 20 pages, 7 figure

Quantum Smoluchowski equation: Escape from a metastable state

We develop a quantum Smoluchowski equation in terms of a true probability distribution function to describe quantum Brownian motion in configuration space in large friction limit at arbitrary temperature and derive the rate of barrier crossing and tunneling within an unified scheme. The present treatment is independent of path integral formalism and is based on canonical quantization procedure.Comment: 10 pages, To appear in the Proceedings of Statphys - Kolkata I