EXOGEN ultrasound bone healing system for long bone fractures with non-union or delayed healing: a NICE medical technology guidance

Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article has been made available through the Brunel Open Access Publishing Fund.A routine part of the process for developing National Institute for Health and Care Excellence (NICE) medical technologies guidance is a submission of clinical and economic evidence by the technology manufacturer. The Birmingham and Brunel Consortium External Assessment Centre (EAC; a consortium of the University of Birmingham and Brunel University) independently appraised the submission on the EXOGEN bone healing system for long bone fractures with non-union or delayed healing. This article is an overview of the original evidence submitted, the EAC’s findings, and the final NICE guidance issued.The Birmingham and Brunel Consortium is funded by NICE to act as an External Assessment Centre for the Medical Technologies Evaluation Programme

Molecular dynamics simulations of vibrated granular gases

We present molecular dynamics simulations of mono- or bidisperse inelastic granular gases driven by vibrating walls, in two dimensions (without gravity). Because of the energy injection at the boundaries, a situation often met experimentally, density and temperature fields display heterogeneous profiles in the direction perpendicular to the walls. A general equation of state for an arbitrary mixture of fluidized inelastic hard spheres is derived and successfully tested against numerical data. Single-particle velocity distribution functions with non-Gaussian features are also obtained, and the influence of various parameters (inelasticity coefficients, density...) analyzed. The validity of a recently proposed Random Restitution Coefficient model is assessed through the study of projected collisions onto the direction perpendicular to that of energy injection. For the binary mixture, the non-equipartition of translational kinetic energy is studied and compared both to experimental data and to the case of homogeneous energy injection (``stochastic thermostat''). The rescaled velocity distribution functions are found to be very similar for both species

Tracer diffusion in granular shear flows

Tracer diffusion in a granular gas in simple shear flow is analyzed. The analysis is made from a perturbation solution of the Boltzmann kinetic equation through first order in the gradient of the mole fraction of tracer particles. The reference state (zeroth-order approximation) corresponds to a Sonine solution of the Boltzmann equation, which holds for arbitrary values of the restitution coefficients. Due to the anisotropy induced in the system by the shear flow, the mass flux defines a diffusion tensor $D_{ij}$ instead of a scalar diffusion coefficient. The elements of this tensor are given in terms of the restitution coefficients and mass and size ratios. The dependence of the diffusion tensor on the parameters of the problem is illustrated in the three-dimensional case. The results show that the influence of dissipation on the elements $D_{ij}$ is in general quite important, even for moderate values of the restitution coefficients. In the case of self-diffusion (mechanically equivalent particles), the trends observed in recent molecular dynamics simulations are similar to those obtained here from the Boltzmann kinetic theory.Comment: 5 figure

Investigating Alternative Measures of Functional Recovery in Rat Sciatic Nerve Injury

There is a pressing need for advancements in peripheral nerve repair techniques and functional recovery evaluation methods. The rat sciatic nerve injury model is a well examined model for peripheral nerve repair. One measure of functional recovery after nerve damage, the sciatic functional index (SFI), fails in the presence of self-mutilation, toe contracture, and other abnormalities in gait. In this IACUC approved study, the sciatic nerve was severed in four experimental groups (n=5). The nerves were repaired with Arginylglycylaspartic acid-poly(ε-caprolactone) (RGD-PCL) peptide functionalized nanofibers, non-functionalized PCL control nanofibers, an isograft, and a negative control empty conduit. Video walking track analysis allowed for a retrospective analysis with three other evaluation techniques: imbalance coupling (IC), stance factor (SF), and toe out angle (TOA). While these techniques are independent of self-mutilation and toe contracture, walking speed remained as a confounding variable. One way repeated measures ANOVA tests showed no significant difference between treatments or subjects in SFI, SF, or TOA. For SFI, 6 and 12 week trials both saw significant increases over time (p=0.00 for both). A significant difference was found between treatments in IC (p=0.03). Imbalance coupling showed promising Pearson correlation with the current industry standard, SFI (p=0.03). In a regression model, SFI over time had an R-squared value of 94.5%. IC, SF, and TOA had low R-squared values. Future investigation with updated protocol is necessary to confirm the degree of correlation and to evaluate the potential for a new industry standard for evaluating nerve repair

Residualism and Rural America: A Decade Later

Rural residents, more so than their urban counterparts are popularly believed to view the use of social welfare programs as appropriate only as last (residual) means of obtaining help. The extent to which this belief reflected reality was assessed by Camasso and Moore (1985) a decade ago using data from a 1980 survey of Pennsylvania residents. Congruent with the residualist hypotheses they found that rural residents were less supportive than urban people of social welfare programming, even when the effects of various personal sociodemographic characteristics were controlled. This paper replicates the workof Camasso and Moore by reporting findings from a similar study carried out a decade later. Although the relative economic and social capital disadvantage of rural people has increased across time, they persist in being more likely than urban residents to express residualist views toward social welfare programming, Implications of these results are discussed

Navier-Stokes transport coefficients of dd-dimensional granular binary mixtures at low density

The Navier-Stokes transport coefficients for binary mixtures of smooth inelastic hard disks or spheres under gravity are determined from the Boltzmann kinetic theory by application of the Chapman-Enskog method for states near the local homogeneous cooling state. It is shown that the Navier-Stokes transport coefficients are not affected by the presence of gravity. As in the elastic case, the transport coefficients of the mixture verify a set of coupled linear integral equations that are approximately solved by using the leading terms in a Sonine polynomial expansion. The results reported here extend previous calculations [V. Garz\'o and J. W. Dufty, Phys. Fluids {\bf 14}, 1476 (2002)] to an arbitrary number of dimensions. To check the accuracy of the Chapman-Enskog results, the inelastic Boltzmann equation is also numerically solved by means of the direct simulation Monte Carlo method to evaluate the diffusion and shear viscosity coefficients for hard disks. The comparison shows a good agreement over a wide range of values of the coefficients of restitution and the parameters of the mixture (masses and sizes).Comment: 6 figures, to be published in J. Stat. Phy

Diffusion of impurities in a granular gas

Diffusion of impurities in a granular gas undergoing homogeneous cooling state is studied. The results are obtained by solving the Boltzmann--Lorentz equation by means of the Chapman--Enskog method. In the first order in the density gradient of impurities, the diffusion coefficient $D$ is determined as the solution of a linear integral equation which is approximately solved by making an expansion in Sonine polynomials. In this paper, we evaluate $D$ up to the second order in the Sonine expansion and get explicit expressions for $D$ in terms of the restitution coefficients for the impurity--gas and gas--gas collisions as well as the ratios of mass and particle sizes. To check the reliability of the Sonine polynomial solution, analytical results are compared with those obtained from numerical solutions of the Boltzmann equation by means of the direct simulation Monte Carlo (DSMC) method. In the simulations, the diffusion coefficient is measured via the mean square displacement of impurities. The comparison between theory and simulation shows in general an excellent agreement, except for the cases in which the gas particles are much heavier and/or much larger than impurities. In theses cases, the second Sonine approximation to $D$ improves significantly the qualitative predictions made from the first Sonine approximation. A discussion on the convergence of the Sonine polynomial expansion is also carried out.Comment: 9 figures. to appear in Phys. Rev.

Self-Reported Familiarity of Hydraulic Fracturing and Support for Natural Gas Drilling: Substantive and Methodological Considerations

The widespread use of hydraulic fracturing in the natural gas industry in the United States has led to criticism by environmentalists and the public who see the process as threatening both the quality and quantity of local water supplies. However, there has been little research directed to assessing the extent to which citizens believe they are familiar with the process of hydraulic fracturing and little analysis dealing with the correlates of subjects’ sociodemographic characteristics with such familiarity or its effects on individual’s support or opposition to natural gas drilling. The current note examines these issues using data from a 2012 study of 800 residents in the core area of the Marcellus natural gas region in Pennsylvania. Substantive and methodological implications of the findings are discussed, as are suggestions for future research

Pennsylvanians\u27 Knowledge of Agriculture

In 2005, researchers at Pennsylvania State University surveyed 1,521 Pennsylvanians in 65 counties to determine their knowledge of and perceptions about agriculture in the state. The study looked to: assess the level of agricultural knowledge of Pennsylvanians; ascertain how personal characteristics and frequency of rural visitation related to agricultural knowledge and to the perceptions of citizens about various agricultural issues; explore the relationship of agricultural knowledge to public perceptions of selected agricultural issues; and suggest how information on Pennsylvanians’ knowledge, experiences, and perceptions of agriculture are relevant to policy makers. The study results showed that, overall, most participants believed they knew very little about the impacts of agriculture on the state, farming production practices, or agriculture and the environment. Their self-rating on matters related to food and nutrition was somewhat higher, but even here a substantial majority believed they were not well-informed. When asked to respond to factual questions dealing with the different knowledge areas, many participants failed to answer correctly, and even those who did select the right answer were seldom certain of their responses. For some questions, respondents who thought their answers were correct often provided the wrong answers. Many of the answers reflected misperceptions about agriculture and its impact on the state. The survey analysis showed that direct personal contact with farming and visiting rural areas were clearly the most important experiences associated with higher levels of agricultural knowledge. The findings also showed that people who have greater agricultural knowledge differ in their views and actions from those with less understanding of agriculture, and this, coupled with the low levels of knowledge found in the population studied, suggests that it is important that efforts be made to educate the public about the nature and impacts of agriculture. To educate the public, the researchers recommended maintaining, and possibly expanding, Agriculture in the Classroom programs that provide agricultural education to school children; developing and expanding programs that allow people to visit working farms in the state; intensifying programs to enhance agricultural tourism and rural visitation; and developing a periodical directed to the general population, which features articles on Pennsylvania farming, agritourism, farm facts and historical notes, and agricultural research findings