5,337 research outputs found

    Mucus Hyperconcentration as a Unifying Aspect of the Chronic Bronchitic Phenotype

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    Abnormalities in mucus production and qualitative properties such as mucus hydration are central to the pathophysiology of airway disease including cystic fibrosis, asthma, and chronic bronchitis. In vitro air–liquid interface epithelial cell cultures demonstrate direct relationships between mucociliary transport, periciliary liquid (PCL) height, and mucus concentration (expressed as percent solids or partial osmotic pressure). In health, the osmotic modulus/pressure of the PCL exceeds that of the mucus layer, resulting in efficient, low-friction movement of mucus. In disease, through multiple mechanisms, the osmotic pressure of the mucus begins to exceed basal PCL values, resulting in compression of the cilia and slowing of mucus transport. The in vivo data in both cystic fibrosis and chronic bronchitis parallel in vitro data demonstrating that when mucus osmotic pressure is increased, mucociliary clearance is decreased. In chronic bronchitis, there is a direct correlation between FEV1 and percent solids of mucus, demonstrating a strong relationship between disease progression and mucus abnormalities. Animal models, based mechanistically on raised sodium absorption (and therefore water absorption) from airway surfaces, mimic the pathophysiology of chronic obstructive pulmonary disease. Collectively, these data suggest the importance of mucus concentration in the pathogenesis of airway disease. It is important to understand the precise mechanisms that result in mucus hyperconcentration, for example, mucin overproduction versus abnormal regulation of ion/water transport, which may be unique to and characteristic of each disease phenotype. The measurement of mucus concentration may be a simple method to diagnose chronic bronchitis, monitor its progression, and serve as a biomarker for development of new therapies

    MIS Legitimacy and the Proposition of a New Multi-dimensional Model of MIS

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    This paper addresses the definition of MIS and the legitimacy of MIS as an academic discipline. Both sides of the MIS legitimacy debate are presented, with the authors embracing the diversity of MIS as a strength that enhances the legitimacy of the MIS discipline. Based on the diversity theory of MIS, the authors propose a new-multidimensional model of MIS that presents a new way of looking at the discipline and the researchers who work in it

    Evaluating a Strategy to Deliver Vaccine to White-tailed Deer at a Landscape Level

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    Effective delivery of vaccines and other pharmaceuticals to wildlife populations is needed when zoonotic diseases pose a risk to public health and natural resources or have considerable economic consequences. The objective of our study was to develop a bait-distribution strategy for potential delivery of oral bovine tuberculosis (bTB) vaccine to white-tailed deer (Odocoileus virginianus) where deer are reservoirs for the disease. During 17 February and 2 March 2011, we created a grid of experimental bait stations (n=64) on Sandhill Wildlife Management Area, Wisconsin, USA, to assess station densities needed to attract and deliver placebo baits to free-ranging white-tailed deer and look for associations among deer density, number of bait stations per deer, and bait consumption. We placed 1 L of commercially available alfalfa cubes at bait stations 652m apart, and monitored stations with motion-activated cameras for 5 days to document visitation and consumption by deer and nontarget species. Deer discovered 38% of all bait stations within 37 hr, on average (SE=3.91 hr), and consumed variable amounts of bait at each station. Deer were documented in 94% of all photographs of wildlife at bait stations. We found no correlation between bait consumption and deer density or the number of bait stations per deer. We provide the first information on use of baits by free-ranging deer and nontarget wildlife to eventually vaccinate deer against bTB at a landscape level. The results of this study can further the development of strategies in delivery of pharmaceuticals to free-ranging white-tailed deer

    Evaluating a Strategy to Deliver Vaccine to White-tailed Deer at a Landscape Level

    Get PDF
    Effective delivery of vaccines and other pharmaceuticals to wildlife populations is needed when zoonotic diseases pose a risk to public health and natural resources or have considerable economic consequences. The objective of our study was to develop a bait-distribution strategy for potential delivery of oral bovine tuberculosis (bTB) vaccine to white-tailed deer (Odocoileus virginianus) where deer are reservoirs for the disease. During 17 February and 2 March 2011, we created a grid of experimental bait stations (n=64) on Sandhill Wildlife Management Area, Wisconsin, USA, to assess station densities needed to attract and deliver placebo baits to free-ranging white-tailed deer and look for associations among deer density, number of bait stations per deer, and bait consumption. We placed 1 L of commercially available alfalfa cubes at bait stations 652m apart, and monitored stations with motion-activated cameras for 5 days to document visitation and consumption by deer and nontarget species. Deer discovered 38% of all bait stations within 37 hr, on average (SE=3.91 hr), and consumed variable amounts of bait at each station. Deer were documented in 94% of all photographs of wildlife at bait stations. We found no correlation between bait consumption and deer density or the number of bait stations per deer. We provide the first information on use of baits by free-ranging deer and nontarget wildlife to eventually vaccinate deer against bTB at a landscape level. The results of this study can further the development of strategies in delivery of pharmaceuticals to free-ranging white-tailed deer

    Development of pseudorandom binary arrays for calibration of surface profile metrology tools

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    Optical Metrology tools, especially for short wavelength (EUV and X-Ray), must cover a wide range of spatial frequencies from the very low, which affects figure, to the important mid-spatial frequencies and the high spatial frequency range, which produces undesirable scattering. A major difficulty in using surface profilometers arises due to the unknown Point-Spread Function (PSF) of the instruments [1] that is responsible for distortion of the measured surface profile. Generally, the distortion due to the PSF is difficult to account because the PSF is a complex function that comes to the measurement via the convolution operation, while the measured profile is described with a real function. Accounting for instrumental PSF becomes significantly simpler if the result of measurement of a profile is presented in a spatial frequency domain as a Power Spectral Density (PSD) distribution [2]. For example, the measured PSD distributions provide a closed set of data necessary for three-dimensional calculations of scattering of light by the optical surfaces [3], [4]. The distortion of the surface PSD distribution due to the PSF can be modeled with the Modulation Transfer Function (MTF), which is defined over the spatial frequency bandwidth of the instrument [1], [2]. The measured PSD distribution can be presented as a product of the squared MTF and the ideal PSD distribution inherent for the System Under Test (SUT). Therefore, the instrumental MTF can be evaluated by comparing a measured PSD distribution of a known test surface with the corresponding ideal numerically simulated PSD. The square root of the ratio of the measured and simulated PSD distributions gives the MTF of the instrument. In previous work [5], [6] the instrumental MTF of a surface profiler was precisely measured using reference test surfaces based on Binary Pseudo-Random (BPR) gratings. Here, we present results of fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. BPR sequences are widely used in engineering and communication applications such as Global Position System, and wireless communication protocols. The ideal BPR pattern has a flat 'white noise' response over the entire range of spatial frequencies of interest. The BPR array used here is based on the Uniformly Redundant Array prescription [7] initially used for x-ray and gamma ray astronomy applications. The URA's superior imaging capability originates from the fact that its cyclical autocorrelation function very closely approximates a delta function, which produces a flat PSD. Three different size BPR array patterns were fabricated by electron beam lithography and ICP etching of silicon. The basic size unit was 200 nm, 400 nm, and 600 nm. Two different etch processes were used, CF{sub 4}/Ar and HBr, which resulted in undercut and vertical sidewall profiles, respectively. The 2D BPR arrays were used as standard test surfaces for MTF calibration of the MicroMap{trademark}-570 interferometric microscope using all available objectives. The HBr etched two-dimensional BPR arrays have proven to be a very effective calibration standard making possible direct calibration corrections without the need of additional calculation considerations, while departures from the ideal vertical sidewall require an additional correction term for the CF{sub 4}/Ar etched samples. [8] Initial surface roughness of low cost 'prime' wafers limits low magnification calibration but should not be a limitation if better polished samples are used

    Attractor states and infrared scaling in de Sitter space

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    The renormalized expectation value of the energy-momentum tensor for a scalar field with any mass m and curvature coupling xi is studied for an arbitrary homogeneous and isotropic physical initial state in de Sitter spacetime. We prove quite generally that has a fixed point attractor behavior at late times, which depends only on m and xi, for any fourth order adiabatic state that is infrared finite. Specifically, when m^2 + xi R > 0, approaches the Bunch-Davies de Sitter invariant value at late times, independently of the initial state. When m = xi = 0, it approaches instead the de Sitter invariant Allen-Folacci value. When m = 0 and xi \ge 0 we show that this state independent asymptotic value of the energy-momentum tensor is proportional to the conserved geometrical tensor (3)H_{ab}, which is related to the behavior of the quantum effective action of the scalar field under global Weyl rescaling. This relationship serves to generalize the definition of the trace anomaly in the infrared for massless, non-conformal fields. In the case m^2 + xi R = 0, but m and xi separately different from zero, grows linearly with cosmic time at late times. For most values of m and xi in the tachyonic cases, m^2 + xi R grows exponentially at late cosmic times for all physically admissable initial states.Comment: 30 pages, 6 figures, 46 kB tar.gz fil
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