468 research outputs found
Randomised clinical trial: the long‐term safety and tolerability of naloxegol in patients with pain and opioid‐induced constipation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108643/1/apt12899.pd
Nonlinear Measures for Characterizing Rough Surface Morphologies
We develop a new approach to characterizing the morphology of rough surfaces
based on the analysis of the scaling properties of contour loops, i.e. loops of
constant height. Given a height profile of the surface we perform independent
measurements of the fractal dimension of contour loops, and the exponent that
characterizes their size distribution. Scaling formulas are derived and used to
relate these two geometrical exponents to the roughness exponent of a
self-affine surface, thus providing independent measurements of this important
quantity. Furthermore, we define the scale dependent curvature and demonstrate
that by measuring its third moment departures of the height fluctuations from
Gaussian behavior can be ascertained. These nonlinear measures are used to
characterize the morphology of computer generated Gaussian rough surfaces,
surfaces obtained in numerical simulations of a simple growth model, and
surfaces observed by scanning-tunneling-microscopes. For experimentally
realized surfaces the self-affine scaling is cut off by a correlation length,
and we generalize our theory of contour loops to take this into account.Comment: 39 pages and 18 figures included; comments to
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Firefly distribution and abundance on mangrove vegetation assemblages in Sepetang estuary, Peninsular Malaysia
Pteroptyx fireflies are commonly reported to congregate in large numbers in mangroves. Not much is known about the relationships between firefly distribution and abundance with specific mangrove vegetation assemblages. We conducted a study to investigate the vegetation assemblages that structure the distribution and abundance of Pteroptyx tener in Peninsular Malaysia. The distribution and abundance of fireflies were assessed along an 8 km stretch of mangroves in Sepetang estuary using visual assessment. Statistical analysis was carried out to test the correlation between length of display section and percentage cover of P. tener colonies and the relationship between percentage cover of fireflies with different vegetation assemblages. Five distinct vegetation assemblages were identified comprising different combination of four mangrove species. It was found that shorter display sections had higher percentage cover of P. tener colonies. In addition, vegetation assemblage which consisting of mainly Sonneratia caseolaris and Nypa fruticans was the most preferred type. The results of this study point to the necessity to consider not only a single mangrove species but the entire vegetation assemblage for firefly conservation
Mutated Measles Virus Matrix and Fusion Protein Influence Viral Titer In Vitro and Neuro-Invasion in Lewis Rat Brain Slice Cultures
Measles virus (MV) can cause severe acute diseases as well as long-lasting clinical deteriorations due to viral-induced immunosuppression and neuronal manifestation. How the virus enters the brain and manages to persist in neuronal tissue is not fully understood. Various mutations in the viral genes were found in MV strains isolated from patient brains. In this study, reverse genetics was used to introduce mutations in the fusion, matrix and polymerase genes of MV. The generated virus clones were characterized in cell culture and used to infect rat brain slice cultures. A mutation in the carboxy-terminal domain of the matrix protein (R293Q) promoted the production of progeny virions. This effect was observed in Vero cells irrespective of the expression of the signaling lymphocyte activation molecule (SLAM). Furthermore, a mutation in the fusion protein (I225M) induced syncytia formation on Vero cells in the absence of SLAM and promoted viral spread throughout the rat brain slices. In this study, a solid ex vivo model was established to elucidate the MV mutations contributing to neural manifestation
Nuances of the psychogastroenterology patient: A predictive model for gastrointestinal quality of life improvement
BackgroundGastrointestinal conditions are multifactorial in nature, and certain patients can benefit greatly from brain–gut psychotherapies delivered by mental health professionals who specialize in psychogastroenterology. This study aimed to identify features associated with improvements in GI‐specific quality of life scores following behavioral health interventions (BHI). The second aim was to create a psychogastroenterology referral care pathway incorporating identified characteristics for greatest benefit from GI‐specific behavioral therapy.MethodsWe performed a prospective observational study of 101 (63 women; median age, 45 years) gastroenterology patients referred for psychogastroenterology consultation at a single center. Patients attended an average of seven sessions with a single GI psychologist where evidence‐based brain–gut psychotherapies were employed. GI‐specific quality of life (IBS‐QOL) and psychological distress (BSI‐18) were assessed before and after BHI. Patients completed self‐reported questionnaires. We performed a multivariable analysis to determine predictors associated with IBS‐QOL score improvement.Key ResultsA total of 53 (52.5%) patients experienced improvement in IBS‐QOL score. Patients with improved IBS‐QOL scores had significantly higher baseline BSI general domain T‐scores (61.9 vs. 56.9, P = 0.002). Female gender (odds ratio [OR], 3.2), pretreatment BSI somatization T‐score ≥63 (OR, 3.7), and a diagnosis of depression (OR, 4.2) were associated with greater odds of IBS‐QOL score improvement following BHI.Conclusions and InferencesWe identified factors associated with response to GI‐specific BHI to aid in optimizing the utilization of psychogastroenterology services and provide referring providers with information to inform treatment recommendations. Female patients with disorders of gut–brain interaction (DGBIs), high somatization, and depression should be considered a priority for brain–gut psychotherapies.Gastrointestinal conditions are multifactorial in nature, and certain patients can benefit greatly from brain–gut psychotherapies delivered by mental health professionals who specialize in psychogastroenterology. Females with disorders of gut–brain interaction, high somatization, and depression should be considered priority for brain–gut psychotherapies. Behavioral health outcomes were not limited to disease; patients with IBD should be routinely considered for referral. Optimizing utilization of GI‐specific behavioral health specialists for the best outcomes can maximize quality of life and disease experience, but also improve value‐based care.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151345/1/nmo13663.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151345/2/nmo13663_am.pd
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The impact of logging roads on dung beetle assemblages in a tropical rainforest reserve
The demand for timber products is facilitating the degradation and opening up of large areas of intact habitats rich in biodiversity. Logging creates an extensive network of access roads within the forest, yet these are commonly ignored or excluded when assessing impacts of logging on forest biodiversity. Here we determine the impact of these roads on the overall condition of selectively logged forests in Borneo, Southeast Asia. Focusing on dung beetles along > 40 km logging roads we determine: (i) the magnitude and extent of edge effects alongside logging roads; (ii) whether vegetation characteristics can explain patterns in dung beetle communities, and; (iii) how the inclusion of road edge forest impacts dung beetle assemblages within the overall logged landscape. We found that while vegetation structure was significantly affected up to 34 m from the road edge, impacts on dung beetle communities penetrated much further and were discernible up to 170 m into the forest interior. We found larger species and particularly tunnelling species responded more than other functional groups which were also influenced by micro-habitat variation. We provide important new insights into the long-term ecological impacts of tropical logging. We also support calls for improved logging road design both during and after timber extraction to conserve more effectively biodiversity in production forests, for instance, by considering the minimum volume of timber, per unit length of logging road needed to justify road construction. In particular, we suggest that governments and certification bodies need to highlight more clearly the biodiversity and environmental impacts of logging roads
Changing perceptions and practices regarding aspirin, nonsteroidal anti-inflammatory drugs, and cyclooxygenase-2 selective nonsteroidal anti-inflammatory drugs among US primary care providers
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74775/1/j.1365-2036.2008.03836.x.pd
A comparison of three fingerstick, whole blood antibody tests for Helicobacter pylori infection: a United States, multicenter trial
We compared three whole blood antibody tests for Helicobacter pylori ( H. pylori ) in a United States, multicenter trial. Methods Patients referred for EGD at three medical centers were recruited. During EGD, biopsies were taken for histology and rapid urease testing (RUT). Immediately after endoscopy, patients underwent the antibody tests (FlexPack HP, Abbott Diagnostics; QuikVue, Quidel Corporation; AccuMeter, ChemTrak) using whole blood obtained by two to three fingersticks. Performance characteristics were calculated for each antibody test using the biopsy-based methods as a gold standard. Results A total of 131 patients participated; 50 (38%) patients had histological evidence of H. pylori infection. Using histology as a gold standard, the sensitivities of FlexPack HP, QuikVue, and Accumeter were 76%, 78%, and 84%, respectively. Specificity was 79% with FlexPack HP and 90% with QuikVue and Accumeter. There were no significant differences in the performance of the three antibody tests though there was a trend toward superior performance for AccuMeter compared to FlexPack HP ( p = 0.019 ). However, RUT proved superior to FlexPack HP using histology as a gold standard ( p = 0.008 ). Using either concordant histology and RUT results or a positive histology or RUT to define active H. pylori infection, there was no statistically significant difference between the antibody tests. Conclusions There were no statistically significant differences in the performance of the three antibody tests. These tests proved only marginally sensitive in detecting patients infected with H. pylori . Clinicians should be aware of the limitations of these tests, particularly when using them as a sole means of testing for H. pylori .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72148/1/j.1572-0241.1999.1135_x.x.pd
Coefficient shifts in geographical ecology: an empirical evaluation of spatial and non-spatial regression
Copyright © 2009 The Authors. Copyright © ECOGRAPHY 2009.A major focus of geographical ecology and macro ecology is to understand the causes of spatially structured ecological patterns. However, achieving this understanding can be complicated when using multiple regressions, because the relative importance of explanatory variables, as measured by regression coefficients, can shift depending on whether spatially explicit or non-spatial modelling is used. However, the extent to which coefficients may shift and why shifts occur are unclear. Here, we analyze the relationship between environmental predictors and the geographical distribution of species richness, body size, range size and abundance in 97 multi-factorial data sets. Our goal was to compare standardized partial regression coefficients of non-spatial ordinary least squares regressions (i.e. models fitted using ordinary least squares without taking autocorrelation into account; “OLS models” hereafter) and eight spatial methods to evaluate the frequency of coefficient shifts and identify characteristics of data that might predict when shifts are likely. We generated three metrics of coefficient shifts and eight characteristics of the data sets as predictors of shifts. Typical of ecological data, spatial autocorrelation in the residuals of OLS models was found in most data sets. The spatial models varied in the extent to which they minimized residual spatial autocorrelation. Patterns of coefficient shifts also varied among methods and datasets, although the magnitudes of shifts tended to be small in all cases. We were unable to identify strong predictors of shifts, including the levels of autocorrelation in either explanatory variables or model residuals. Thus, changes in coefficients between spatial and non-spatial methods depend on the method used and are largely idiosyncratic, making it difficult to predict when or why shifts occur. We conclude that the ecological importance of regression coefficients cannot be evaluated with confidence irrespective of whether spatially explicit modelling is used or not. Researchers may have little choice but to be more explicit about the uncertainty of models and more cautious in their interpretation
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