1,720,965 research outputs found
Hypoxic-State Estimation of Brain Cells by Using Wireless Near-Infrared Spectroscopy
No full textNear-infrared spectroscopy (NIRS) is a modern measuring technology in neuroscience. It can be used to noninvasively measure the relative concentrations of oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoHb), which can reflect information related to cerebral blood volume and cerebral oxygen saturation. Therefore, it has the potential for noninvasive monitoring of cerebral ischemia. However, there is still a lack of reliable physiological information on the relationship between the concentrations of OxyHb and DeoHb in cerebral blood and the exact hypoxic state of brain cells under cerebral ischemia. In this study, we describe a wireless multichannel NIRS system, which we designed to noninvasively monitor the relative concentrations of OxyHb and DeoHb in bilateral cerebral blood before, during, and after middle cerebral artery occlusion. By comparing the results with the lactate/pyruvate ratio measured by microdialysis, we investigated the correlation between the relative concentrations of OxyHb and DeoHb in cerebral blood and the hypoxic state of brain cells. The results showed that the relationship between the concentration changes of DeoHb in cerebral blood and the hypoxic state of brain cells was significant. Therefore, by monitoring the changes in concentrations of DeoHb, the wireless NIRS can be used to estimate the hypoxic state of brain cells indirectly
The neuronal protective effects of local brain cooling at the craniectomy site after lateral fluid percussion injury in a rat model
No full textBackground: The aim of the present study is to investigate whether local brain cooling at the craniectomy site causes attenuation of traumatic brain injury (TBI) induced by fluid percussion injury (FPI).
Methods: Anesthetized male SpragueeDawley rats were divided into two major treatment groups. Immediately after the onset of fluid percussion TBI, a craniectomy window of 6 x 8 mm was made at the right parietal, and a cold water bag (0 x C-1 x degrees C or 5 x C-6 degrees C) was applied locally for 30 min. Additional groups of rats were used as craniectomy and craniectomy FPI controls. Physiological parameters, such as brain and colonic temperature, mean arterial pressure, and heart rate, were monitored during FPI. Functional motor outcomes were evaluated using the inclined plane test (maximal grasp angle). Cellular infarction volume was calculated using triphenyltetrazolium chloride staining. Apoptosis and neuronal markerepositive cells in the cortex were measured by immunofluorescence staining. All functional and morphologic parameters were assessed 72 h after injury.
Results: Compared with the craniectomy + FPI control groups, the groups treated with 5 degrees C-6 degrees C local cold water therapy showed significant attenuation of the FPI-induced motor deficits, weight loss, and cerebral infarction but no effect on colonic temperature. The FPI-induced apoptosis and neuronal loss were also significantly reduced by local cooling.
Conclusions: Our results suggest that local cooling with 5 degrees C-6 degrees C cold water therapy may ameliorate TBI in rats by reducing infarction volume, neuronal cell loss, and apoptosis, resulting in improved functional outcome. We propose that the use of local cooling at the craniectomy site after FPI might have clinical benefits in the future. (C) 2013 Elsevier Inc. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Brain temperature management in traumatic brain injury
No full textSummaryAfter a primary traumatic brain injury (TBI), the secondary brain damage that results from ischemia and reperfusion cascades is rather complex. The benefits and the mechanisms of action in whole-body cooling and selective brain cooling after TBI have been well investigated in animal studies. Despite a significant number of positive reports, induced hypothermia is not recommended as standard care for TBI patients in clinical practice because of its uncertain results. Furthermore, some authors have recommended maintaining normothermia and avoiding hyperthermia, although a consensus regarding the effective use of hypothermia in TBI patients has not been well established. In this paper, we propose that brain hyperthermia can be avoided early by maintaining, for at least 72 hours, a temperature ranging from normothermia to mild hypothermia (36–37.5°C), which is accomplished by utilizing selective brain cooling on the craniectomy side with an ice bag or by implementing other cooling systems. This may be a promising strategy when treating patients with severe TBI. However, further prospective research is clearly indicated to delineate the risks and benefits associated with these new therapies
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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