Articles: function.
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Bump attractors are localized activity patterns that can self-sustain after stimulus presentation, and they are regarded as the neural substrate for a host of perceptual and cognitive processes. One of the characteristic features of bump attractors is that they are neutrally stable, so that noisy inputs cause them to drift away from their initial locations, severely impairing the accuracy of bump location-dependent neural coding. Previous modeling studies of such noise-induced drifting activity of bump attractors have focused on normal diffusive dynamics, often with an assumption that noisy inputs are uncorrelated. ⋯ We demonstrate that subdiffusive dynamics can significantly improve the coding accuracy of bump attractors, since the variance of the bump displacement increases sublinearly over time and is much smaller than that of normal diffusion. Furthermore, we reanalyze existing psychophysical data concerning the spread of recalled cue position in spatial working memory tasks and show that its variance increases sublinearly with time, consistent with subdiffusive dynamics of bump attractors. Based on the probability density function of bump position, we also show that the subdiffusive dynamics result in a long-tailed decay of firing rate, greatly extending the duration of persistent activity.
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Anesthesia and analgesia · Feb 2015
The Effects of Exogenous Surfactant Treatment in a Murine Model of Two-Hit Lung Injury.
Because pulmonary endogenous surfactant is altered during acute respiratory distress syndrome, surfactant replacement may improve clinical outcomes. However, trials of surfactant use have had mixed results. We designed this animal model of unilateral (right) lung injury to explore the effect of exogenous surfactant administered to the injured lung on inflammation in the injured and noninjured lung. ⋯ Exogenous surfactant administration to an acid-injured right lung improved gas exchange and whole respiratory system compliance. However, markers of inflammation increased in the right (injured) lung, although this result was not found in the left (uninjured) lung. These data suggest that the mechanism by which surfactant improves lung function may involve both uninjured and injured alveoli.
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Laura Dattner, John Krai and Linda Oppenheim provided assistance in obtaining archival material and manuscript review. Edwin Rosenthal's decedents, Robert, Eleanore Jane and Edwin Rosenthal II, provided information about their distinguished grandfather's life and commitments. Linda Oppenheim, Michael Angelo, Jessica Lydon, and Sofie Serada, archivists at Princeton University, Thomas Jefferson University, Temple University, and the College of Physicians of Philadelphia provided access to material on Edwin Rosenthal and medical care in Philadelphia at the turn of the 20th century. We thanks Laura Dattner, John Krai and Linda Oppenheim for their manuscript review. ⋯ Mortality from diphtheria dropped precipitously at the end of the 19th century with the introduction of laryngecostomy and a diphtheria antitoxin. However these measures required action by health departments and was dependent on the availability of physicians and medical facilities. Lack of Public Health Departments put all southerners at risk for infectious illnesses. With respect to diphtheria, there was neither an available supply of antitoxin nor physician care available. Philadelphia may have been too mired in corruption to provide antitoxin. Burghardt lived in close proximity to a facility where antitoxin was available, data suggests he would have received appropriate treatment there and was likely to have survived. Similar phenomena-disinterest and dysfunction-affect provision of immunization for children today. Currently, availability of immunization is affected by ethnicity, income levels and immigration status.
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Review Meta Analysis Comparative Study
[Opioids in chronic low back pain : A systematic review and meta-analysis of efficacy, tolerability and safety in randomized placebo-controlled studies of at least 4 weeks duration.]
The efficacy and safety of opioid therapy in chronic low back pain (CLBP) is under debate. We updated a recent systematic review on the efficacy and safety of opioids in CLBP. ⋯ Opioids were superior to placebo in terms of efficacy and inferior in terms of tolerability. Opioids and placebo did not differ in terms of safety during the study period. The conclusion on the safety of opioids compared to placebo is limited by the low number of serious adverse events and deaths. Short-term and intermediate-term opioid therapy may be considered in selected CLBP patients. The English full-text version of this article is freely available at SpringerLink (under "Supplemental").