5,145 research outputs found

    Double Decker Enrichment cages have no effect on long term nociception in neuropathic rats but increase exploration while decreasing anxiety-like behaviors

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    In this present study, we investigated the impact of environmental enrichment in Sprague Dawley rats up to three months after a chronic or sham nerve injury. Sprague Dawley rats were housed in either standard polycarbonate cages or rat enrichment cages. Following 2 weeks of training and the recording of baseline behavioral values, half of the animals underwent a right sciatic nerve chronic constriction injury (CCI) surgery under general anaesthesia to induce chronic neuropathic pain. The other animals underwent a sham surgery. Animals were then evaluated once a month for 3 consecutive months in different behavioural tests for of mechanical and heat sensitivities as well as for exploration and anxiety-like behaviors. Mechanical and heat sensitivities were also tested at 15 days following the surgery. One month following the surgery, half of the rats in each group (CCI and sham) were either left in the standard rat cages or placed in the Double Decker cages. Environmental enrichment did not affect the mechanical or heat sensitivity of neuropathic animals; however exploration increased, and anxiety-like behaviours decreased, significantly (p<0.01). These results clearly show that environmental enrichment can have a significant impact on exploratory and anxiety-like behaviour in neuropathic rats without modifying pain hypersensitivity

    Central Pain Following a Collagenase-Induced Hematoma in the Basal Ganglia and Thalamus Can Be Reversed with Gabapentin

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    The objective of this study was to evaluate pain sensitization in rats following the induction of an intracerebral haemorrhage located in the basal ganglia and/or thalamus using the Rosenberg model (intracerebral injection of collagenase). Thirty male Sprague-Dawley rats weighing between 175-300 g were used. In a first experiment, 3 groups of 6 animals were used to evaluate pain threshold using the Hargreaves test (thermal sensitivity). Following 3 days of behavioural testing (baseline values), animals in each group were injected intracerebrally either with 0.5, 1 or 2 μL of a collagenase solution (0.5 U/2 μL Type VII collagenase) which induced a hematoma in the right caudoputamen nucleus and/or thalamus. They were then tested for the next 9 consecutive days. No pain-related behavioural changes were observed following injections with 0.5 and 1 μL of collagenase. However with 2 μL, reaction times were significantly faster on days 3, 4, 5, 6 (p < 0.0001) and 7 (p < 0.006) in the right and left hind paws compared to baseline values. The lesion was localized only in the caudoputamen nucleus for animals receiving 0.5 and 1 μL of collagenase whereas lesions extended in the ipsilateral thalamic nuclei (lateral-dorsal and lateral-posterior nuclei) for animals receiving 2 μL of collagenase. In a second experiment, gabapentin reversed mechanical allodynia, evaluated with von Frey filaments, and hyperalgesia, evaluated with Hargreaves test, in rats (n=6) following a collagenase-induced (3 μL) hematoma. In conclusion, these preliminary results suggest that central pain was induced in rats with a collagenase-induced intracerebral haemorrhage localized in the caudoputamen nuclei most probably associated with lesions to the thalamus, and concurrent allodynia and hyperalgesia were reduced with gabapentin treatment

    Attention Allocation Aid for Visual Search

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    This paper outlines the development and testing of a novel, feedback-enabled attention allocation aid (AAAD), which uses real-time physiological data to improve human performance in a realistic sequential visual search task. Indeed, by optimizing over search duration, the aid improves efficiency, while preserving decision accuracy, as the operator identifies and classifies targets within simulated aerial imagery. Specifically, using experimental eye-tracking data and measurements about target detectability across the human visual field, we develop functional models of detection accuracy as a function of search time, number of eye movements, scan path, and image clutter. These models are then used by the AAAD in conjunction with real time eye position data to make probabilistic estimations of attained search accuracy and to recommend that the observer either move on to the next image or continue exploring the present image. An experimental evaluation in a scenario motivated from human supervisory control in surveillance missions confirms the benefits of the AAAD.Comment: To be presented at the ACM CHI conference in Denver, Colorado in May 201

    Pubertal development of penile Nitric Oxide Synthase (NOS)-containing nerve fibers in the rat

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    Objectives: To evaluate the expression of nitric oxide synthase (NOS)-containing nerve fibers in penile tissue in different age groups in the rat and to measure serum testosterone levels during this developmental process. Material and Methods: Fifteen male Sprague-Dawley (SD) rats divided into 3 equally numbered groups of different age (40 days (d), 54d and 65d) were used in this study. Penile erection was evaluated using cavernous nerve electrostimulation. Before sacrificing the rats, a penile midshaft specimen was taken for nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining and blood samples were collected to evaluate the testosterone levels. Results: Electrostimulation of the cavernous nerve revealed no significant difference in the maximal intracavernous pressure in the different age groups (44.9 ± 6.4, 54.8 ± 24.8, 45.9 ± 16.8 cm H2O, respectively; p>0.05), but the latency of the response to electrostimulation was significantly shorter in 54d and 65d than in 40d-old rats (5.4 ± 0.8 and 5.0 ± 0.7 vs. 9.0 ± 5.4 sec., respectively;

    Intercomparison of two-dimensional wave spectra obtained from microwave instruments, buoys and WAModel simulations during the surface wave dynamics experiment

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    An intercomparison is made of two dimensional wave spectra obtained from buoys and various remote sensing microwave systems and predicted by the WAModel dur- ing the Surface Wave Dynamics Experiment (SWADE). The overall agreement be- tween the measurements and the model is satifactory, but some differences in detail require further investigation. The buoy data yield reliable mean spectral parame- ters, but the maximum likelihood retrieval algorithm tends to produce directional distributions that are broader than those of other instruments. Various microwave instruments (ROWS, RESSAC, SRA) show good promise for the determination of 2d-wave spectra, but exhibit individual shortcomings (calibration uncertainties, di- rectional ambiguity, impact of aircraft motion) that need to be further studied. The SAR system yields reliable retrievals with respect to the general spectral dis- tribution, but suffers in this experiment from an undetermined calibration factor. Deviations between the WAModel and instrumental data could be largely attributed to wind field errors, but the model also exhibits deficiencies in the development of short-fetch wave systems and in the wave spectral response to rapidly turning wind fields

    OntoGene in BioCreative II

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    BACKGROUND: Research scientists and companies working in the domains of biomedicine and genomics are increasingly faced with the problem of efficiently locating, within the vast body of published scientific findings, the critical pieces of information that are needed to direct current and future research investment. RESULTS: In this report we describe approaches taken within the scope of the second BioCreative competition in order to solve two aspects of this problem: detection of novel protein interactions reported in scientific articles, and detection of the experimental method that was used to confirm the interaction. Our approach to the former problem is based on a high-recall protein annotation step, followed by two strict disambiguation steps. The remaining proteins are then combined according to a number of lexico-syntactic filters, which deliver high-precision results while maintaining reasonable recall. The detection of the experimental methods is tackled by a pattern matching approach, which has delivered the best results in the official BioCreative evaluation. CONCLUSION: Although the results of BioCreative clearly show that no tool is sufficiently reliable for fully automated annotations, a few of the proposed approaches (including our own) already perform at a competitive level. This makes them interesting either as standalone tools for preliminary document inspection, or as modules within an environment aimed at supporting the process of curation of biomedical literature

    Radiocarbon dating of methane and carbon dioxide evaded from a temperate peatland stream

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    Streams draining peatlands export large quantities of carbon in different chemical forms and are an important part of the carbon cycle. Radiocarbon (14C) analysis/dating provides unique information on the source and rate that carbon is cycled through ecosystems, as has recently been demonstrated at the air-water interface through analysis of carbon dioxide (CO2) lost from peatland streams by evasion (degassing). Peatland streams also have the potential to release large amounts of methane (CH4) and, though 14C analysis of CH4 emitted by ebullition (bubbling) has been previously reported, diffusive emissions have not. We describe methods that enable the 14C analysis of CH4 evaded from peatland streams. Using these methods, we investigated the 14C age and stable carbon isotope composition of both CH4 and CO2 evaded from a small peatland stream draining a temperate raised mire. Methane was aged between 1617-1987 years BP, and was much older than CO2 which had an age range of 303-521 years BP. Isotope mass balance modelling of the results indicated that the CO2 and CH4 evaded from the stream were derived from different source areas, with most evaded CO2 originating from younger layers located nearer the peat surface compared to CH4. The study demonstrates the insight that can be gained into peatland carbon cycling from a methodological development which enables dual isotope (14C and 13C) analysis of both CH4 and CO2 collected at the same time and in the same way

    Lake-size dependency of wind shear and convection as controls on gas exchange

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    High-frequency physical observations from 40 temperate lakes were used to examine the relative contributions of wind shear (u*) and convection (w*) to turbulence in the surface mixed layer. Seasonal patterns of u* and w* were dissimilar; u* was often highest in the spring, while w * increased throughout the summer to a maximum in early fall. Convection was a larger mixed-layer turbulence source than wind shear (u */w*-1 for lakes* and w* differ in temporal pattern and magnitude across lakes, both convection and wind shear should be considered in future formulations of lake-air gas exchange, especially for small lakes. © 2012 by the American Geophysical Union.Jordan S. Read, David P. Hamilton, Ankur R. Desai, Kevin C. Rose, Sally MacIntyre, John D. Lenters, Robyn L. Smyth, Paul C. Hanson, Jonathan J. Cole, Peter A. Staehr, James A. Rusak, Donald C. Pierson, Justin D. Brookes, Alo Laas, and Chin H. W
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