585 research outputs found

    Identification of barriers and beliefs influencing engagement by adult and teen Mexican-Americans in oral health behaviors

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    OBJECTIVE: To identify barriers and beliefs influencing oral health and dental care-seeking among Mexican-Americans. RESEARCH DESIGN: Interviews and Likert-scale survey questions were utilized to explore urgent and preventive dental care-seeking, oral hygiene habits and lifestyle practices. Thirty-three interviews were conducted with 16 adults (ages 33-52), and 17 adolescents (ages 14-19). RESULTS: Teens identified the same main barriers to accessing dental care as adults: high cost, financial limitations and lack of insurance. Most Mexican-Americans agreed with the belief that everyone will need urgent dental treatment and the majority believed that going to a dentist in private practice instead of the Emergency Room was important. Although adults recognized the importance of preventive dental care, half reported being unlikely to seek such care while half of teens reported that they were likely to do so. Adults reported relying equally on themselves and on peers to make dental care decisions, while teens mostly depended on others to make decisions about urgent and preventive care. Virtually all respondents believed regular brushing to be important and many flossing too. A major barrier to flossing was being unsure of the proper technique. Another barrier to better oral health was not having seen messages encouraging changes in lifestyle. CONCLUSIONS: This study found that Mexican-American teens and adults may experience oral health similarly. Teens do not have more positive oral health beliefs and encounter mostly the same barriers to care as adults

    Investigating TMS–EEG indices of long-interval intracortical inhibition at different interstimulus intervals

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    Available online 8 August 2016Abstract not availableGeorge M. Opie, Nigel C. Rogasch, Mitchell R. Goldsworthy, Michael C. Ridding, John G. Semmle

    5-Aminolevulinic acid-mediated fluorescence diagnosis of colon cancer: A histopathological comparison of fluorescent and non-fluorescent tumours

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    Background: 5-Aminolevulinic acid (5-ALA) selectively accumulates in cancer cells and is metabolised in the mitochondria to the fluorophore protoporphyrin IX. The GLiSten trial evaluated 5-ALA as a fluorescent probe for intraoperative detection of colon cancer and lymph node metastases. Only 13 of 40 cases showed fluorescence, suggesting a fundamental difference between fluorescent and non-fluorescent cancers. The aim of this study was to investigate whether differences in fluorescence were due to tumour cellularity, in particular T cell infiltration, which may be of prognostic significance. Method: Primary tumour tissue was available from 30 patients. The density of tumour cells, vascularity and stromal compartment size were quantified using digitally scanned tissue sections stained with haematoxylin and eosin. A set of 300 random points was superimposed onto each tumour image. The structure indicated by each point was then categorised as tumour, stroma, vessel or other. The proportions of tumour and vessel points gave the tumour cell density and vessel density respectively. The relative size of the stromal compartment was given by the tumour to stroma ratio. A tissue section was also stained for the T cell marker CD3 by immunohistochemistry. Percentage staining was quantified in three high-density fields using the Nuance imaging system. Results: We were unable to detect any difference between fluorescent and non-fluorescent cancers in terms of tumour cell density (difference in means 3.7%; P = 0.452), vessel density (difference in means 0.17%; P = 0.684), tumour-stroma ratio (difference in mean ratios 0.12; P = 0.934), or T cell count (difference in means 0.92%; P = 0.726). Furthermore, comparisons of the distributions of each variable demonstrated substantial overlap between the fluorescent and non-fluorescent cohorts. Conclusion: The results suggest that tumour and microenvironment structure do not differ between cancers that fluoresce with 5-ALA and those that do not. We therefore propose that the cellular metabolism of 5-ALA is a more likely explanation for differential fluorescence

    Probabilistic analysis of multi-layered soil effects on shallow foundation settlement

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    The document attached has been archived with permission from the copyright holder.The results of a preliminary investigation into the effects of multi-layered soil on foundation settlement are reported in this paper. In this study, the settlement of a square pad footing placed on two-layered soil profile is examined. Using a combination of Finite Element Method (FEM) analyses and random fields simulation, probabilistic analyses of the settlement of footing founded on two-layered soil profile is established through Monte Carlo simulation. The Young’s modulus field has been simulated via Local Average Subdivision method (LAS) with a fixed mean, various coefficients of variation and spatial correlation structures. The coefficients of variation and spatial correlation structures in each layer are set to be different. It is assumed that the boundary between two soil layers is abrupt as may be represented by faults and geological unconformities in the soil mass. The results of the analyses indicate a modest decrease in the coefficient of variation of settlement of the 2-layered soil profile compared to the settlement of the uniform single layer soil mass

    Influence of site investigations on the design of pad footings

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    The document attached has been archived with permission from the copyright holder.The reliability of foundations is greatly influenced by uncertainties associated with the geotechnical model on which their design is based. In turn, the geotechnical model is derived from a site investigation whose scope is largely dictated by financial constraints, rather than the variability of the ground. This paper seeks to quantify the influence of the scope of site investigations on the design of pad footings. This is achieved by simulating geotechnical profiles, where the soil properties vary from location to location in a random yet continuous and realistic fashion. The simulated soil profiles are generated using random field theory, which makes use of three statistical parameters: the mean, variance and the scale of fluctuation – which is a measure of the randomness of the geotechnical property in question. The methodology involves generating a geotechnical profile by simulating a 3D random field to know soil properties at each point in detail. A site investigation is then simulated by sampling from the 3D random field. By using the sampled values, a pad footing is designed to conform to a serviceability criterion, as would be achieved in practice. A benchmark design is also undertaken making use of the complete knowledge of the soil profile. This design is achieved using a numerical process involving a 3D finite element analysis. Both designs are undertaken on numerous different simulated soil profiles in a Monte Carlo analysis. A comparison of the two designs provides failure and over-design probabilities for a series of site investigation plans. It was observed that the probability of failure and overdesign decreased with an increasing site investigation scope, as expected. The results provide information to estimate the relative benefit of conducting various scopes of site investigations

    Non-Equilibrium Reaction Rates in the Macroscopic Chemistry Method for DSMC Calculations

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    The Direct Simulation Monte Carlo (DSMC) method is used to simulate the flow of rarefied gases. In the Macroscopic Chemistry Method (MCM) for DSMC, chemical reaction rates calculated from local macroscopic flow properties are enforced in each cell. Unlike the standard total collision energy (TCE) chemistry model for DSMC, the new method is not restricted to an Arrhenius form of the reaction rate coefficient, nor is it restricted to a collision cross-section which yields a simple power-law viscosity. For reaction rates of interest in aerospace applications, chemically reacting collisions are generally infrequent events and, as such, local equilibrium conditions are established before a significant number of chemical reactions occur. Hence, the reaction rates which have been used in MCM have been calculated from the reaction rate data which are expected to be correct only for conditions of thermal equilibrium. Here we consider artificially high reaction rates so that the fraction of reacting collisions is not small and propose a simple method of estimating the rates of chemical reactions which can be used in the Macroscopic Chemistry Method in both equilibrium and non-equilibrium conditions. Two tests are presented: (1) The dissociation rates under conditions of thermal non-equilibrium are determined from a zero-dimensional Monte-Carlo sampling procedure which simulates ‘intra-modal’ non-equilibrium; that is, equilibrium distributions in each of the translational, rotational and vibrational modes but with different temperatures for each mode; (2) The 2-D hypersonic flow of molecular oxygen over a vertical plate at Mach 30 is calculated. In both cases the new method produces results in close agreement with those given by the standard TCE model in the same highly nonequilibrium conditions. We conclude that the general method of estimating the non-equilibrium reaction rate is a simple means by which information contained within non-equilibrium distribution functions predicted by the DSMC method can be included in the Macroscopic Chemistry Method

    Two-microphone spatial filtering provides speech reception benefits for cochlear implant users in difficult acoustic environments

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    This article introduces and provides an assessment of a spatial-filtering algorithm based on two closely-spaced (∼1 cm) microphones in a behind-the-ear shell. The evaluated spatial-filtering algorithm used fast (∼10 ms) temporal-spectral analysis to determine the location of incoming sounds and to enhance sounds arriving from straight ahead of the listener. Speech reception thresholds (SRTs) were measured for eight cochlear implant (CI) users using consonant and vowel materials under three processing conditions: An omni-directional response, a dipole-directional response, and the spatial-filtering algorithm. The background noise condition used three simultaneous time-reversed speech signals as interferers located at 90°, 180°, and 270°. Results indicated that the spatial-filtering algorithm can provide speech reception benefits of 5.8 to 10.7 dB SRT compared to an omni-directional response in a reverberant room with multiple noise sources. Given the observed SRT benefits, coupled with an efficient design, the proposed algorithm is promising as a CI noise-reduction solution.National Institutes of Health (U.S.) (Grant R01 DC 000117)National Institutes of Health (U.S.) (Grant R01 DC DC7152)National Institutes of Health (U.S.) (Grant 2R44DC010524-02

    Howard Florey, Alexander Fleming and the fairy tale of penicillin

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    The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.The public myth of the discovery of penicillin is an archetypal "quest story" of the type common to every human culture. But the real story of the discovery, testing and refinement of penicillin is a complex tale of accident, serendipity, oversight, conflict, the pressure of war, idiosyncratic personalities and even - the invention of history.Peter D Goldsworthy and Alexander C McFarlan
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