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Search Results: 1 - 10 of 229474 matches for " George C. Wellman "
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Subarachnoid Hemorrhage, Spreading Depolarizations and Impaired Neurovascular Coupling
Masayo Koide,Inna Sukhotinsky,Cenk Ayata,George C. Wellman
Stroke Research and Treatment , 2013, DOI: 10.1155/2013/819340
Abstract:
Subarachnoid Hemorrhage, Spreading Depolarizations and Impaired Neurovascular Coupling
Masayo Koide,Inna Sukhotinsky,Cenk Ayata,George C. Wellman
Stroke Research and Treatment , 2013, DOI: 10.1155/2013/819340
Abstract: Aneurysmal subarachnoid hemorrhage (SAH) has devastating consequences on brain function including profound effects on communication between neurons and the vasculature leading to cerebral ischemia. Physiologically, neurovascular coupling represents a focal increase in cerebral blood flow to meet increased metabolic demand of neurons within active regions of the brain. Neurovascular coupling is an ongoing process involving coordinated activity of the neurovascular unit—neurons, astrocytes, and parenchymal arterioles. Neuronal activity can also influence cerebral blood flow on a larger scale. Spreading depolarizations (SD) are self-propagating waves of neuronal depolarization and are observed during migraine, traumatic brain injury, and stroke. Typically, SD is associated with increased cerebral blood flow. Emerging evidence indicates that SAH causes inversion of neurovascular communication on both the local and global level. In contrast to other events causing SD, SAH-induced SD decreases rather than increases cerebral blood flow. Further, at the level of the neurovascular unit, SAH causes an inversion of neurovascular coupling from vasodilation to vasoconstriction. Global ischemia can also adversely affect the neurovascular response. Here, we summarize current knowledge regarding the impact of SAH and global ischemia on neurovascular communication. A mechanistic understanding of these events should provide novel strategies to treat these neurovascular disorders. 1. Pathophysiology of Subarachnoid Hemorrhage Aneurysmal subarachnoid hemorrhage (SAH) is associated with high morbidity and mortality with limited therapeutic options [1]. The major contributor to poor outcome of patients surviving the initial surge in intracranial pressure is delayed cerebral ischemia (DCI) manifesting 4–10 days after aneurysm rupture as new and otherwise unexplained neurological deficits and/or ischemic lesions within the brain [2]. Despite decades of study, mechanisms contributing to SAH-induced DCI remain controversial. For many years, a delayed and prolonged vasospasm of large conduit arteries was thought to be the major contributor to DCI and the ensuing death and disability observed in SAH patients [3, 4]. Recent data, however, challenge this view [5–7] and strongly suggest that additional mechanisms contribute to poor outcomes after SAH, including early brain injury suffered at the time of bleed [6, 8–10], blood-brain barrier disruption [11, 12], inflammation [13–15], and impaired microcirculatory function [16–19]. Evidence suggests that a pathological inversion of
Coinfección de tuberculosis en pacientes con VIH/SIDA: un análisis según las fuentes de información en Colombia
CASTIBLANCO,CéSAR AUGUSTO; RIBóN,WELLMAN;
Infectio , 2006,
Abstract: introduction. today, the worldwide information about the infection of the virus of the human immunodeficiency (vih) seems to be increasing in two dimensions: one is the number of infected people in the world and the other is the amount of publications which are generated in all fields of knowledge about the infection. although, the situation of the coinfection of tuberculosis (tb) and vih is unknown due to the difficulty of getting information about it or simply, because there is not information at all. methods and materials. an analysis of the situation of coinfection tb/vih was made in the colombian national health information systems during the last years. results. it was evident that during the year 2005 only 11 of the 36 territorial organizations reported cases of coinfection tb/vih. before the merge of information into one system, the territorial organizations made different analyses from that information. due to this, it was not possible to compare the coinfection tb/vih at a nationwide level. data available were analyzed according to the sources of information. discussion. we expect that the unification of the information systems can provide the data that allow to make a situation analysis at a national level.
Coinfección de tuberculosis en pacientes con VIH/SIDA: un análisis según las fuentes de información en Colombia Tuberculosis and HIV/AIDS co-infected patients: Analysis from Colombian information sources
CéSAR AUGUSTO CASTIBLANCO,WELLMAN RIBóN
Infectio , 2006,
Abstract: Introducción. La información de la infección del virus de la inmunodeficiencia humana (VIH) en el mundo parece aumentar en dos dimensiones: una es el número de infectados sobre la faz de la tierra y la otra es la cantidad de conocimiento que se genera en todos los campos acerca del tema. Sin embargo, la situación sobre la coinfección de tuberculosis y VIH/ sida no se conoce debido al difícil acceso a las fuentes de información o la inexistencia de las mismas. Materiales y métodos. Se realizó un análisis de la situación de la coinfección de tuberculosis y VIH/sida en los sistemas de información nacional durante los últimos a os. Resultados. Se evidenció que durante el 2005 sólo 11 de las 36 entidades territoriales reportaron casos de coinfección de tuberculosis y VIH. Antes de la unificación en el sistema de información, las entidades territoriales realizaban diferentes análisis de la información, razón que no permitió la comparación de la situación de la coinfección de tuberculosis y VIH a nivel nacional. Se analizaron datos disponibles según las fuentes de información. Discusión. Se espera que con la unificación en los sistemas de información se puedan obtener datos que permitan realizar un análisis de la situación a nivel nacional. Introduction. Today, the worldwide information about the infection of the virus of the human immunodeficiency (VIH) seems to be increasing in two dimensions: one is the number of infected people in the world and the other is the amount of publications which are generated in all fields of knowledge about the infection. Although, the situation of the coinfection of tuberculosis (TB) and VIH is unknown due to the difficulty of getting information about it or simply, because there is not information at all. Methods and materials. An analysis of the situation of coinfection TB/VIH was made in the Colombian national health information systems during the last years. Results. It was evident that during the year 2005 only 11 of the 36 territorial organizations reported cases of coinfection TB/VIH. Before the merge of information into one system, the territorial organizations made different analyses from that information. Due to this, it was not possible to compare the coinfection TB/VIH at a nationwide level. Data available were analyzed according to the sources of information. Discussion. We expect that the unification of the information systems can provide the data that allow to make a situation analysis at a national level.
Molecular tools for Mycobacterium tuberculosis genotyping
Rozo-Anaya,Juan C; Ribón,Wellman;
Revista de Salud Pública , 2010, DOI: 10.1590/S0124-00642010000300016
Abstract: objective the present work studied molecular typing methods used for mycobacterium tuberculosis characterization in order to learn about their advantages, disadvantages and discrimination power as regards the implementation of tuberculosis surveillance and control programs. methods to analyze the discrimination power of each method we studied articles that included hunter-gaston discrimination index (hgdi) values or data allowing their calculation. results the highest discrimination power was registered for lm-pcr followed by flip and 15-loci miru. the most frequently used methods showed an hgdi of 0.9491, 0.9519 and 0.8630 for 12-loci miru, rflp-is6110 and spoligotyping, respectively. conclusion m. tuberculosis isolates molecular characterization requires at least two molecular markers to discriminate non related isolates, as well as previous analysis to their implementation.
El análisis estructural: del método y la metáfora alateoría y la sustancia
Barry Wellman
Política y Sociedad , 2000, DOI: -
Abstract: Sin resumen
Identification of Issues in Predicting Multi-Robot Performance through Model-Based Simulations  [PDF]
Shameka Dawson, Briana Lowe Wellman, Monica Anderson
Intelligent Control and Automation (ICA) , 2011, DOI: 10.4236/ica.2011.22016
Abstract: Predicting the performance of intelligent multi-robot systems is advantageous because running physical experiments with teams of robots can be costly and time consuming. Controlling for every factor can be difficult in the presence of minor disparities (i.e. battery charge). Access to a variety of environmental configurations and hardware choices is prohibitive in many cases. With the eminent need for dependable robot controllers and algorithms, it is essential to understand when real robot performance can be accurately predicted. New prediction methods must account for the effects of digital and physical interaction between the robots that are more complex than just collision detection of 2D or physics-based 3D models. In this paper, we identify issues in predicting multi-robot performance and present examples of statistical and model-based simulation methods and their applicability to multi-robot systems. Even when sensor noise, latency and environmental configuration are modeled in some complexity, multi-robot systems interject interference and messaging latency, causing many prediction systems to fail to correlate to absolute or relative performance. We support this supposition by comparing results from 3D physics-based simulations to identical experiments with a physical robot team for a coverage task.
Facing the Enemy Head-On: The Role of Pasimba Radio Program in Promoting the Fight against HIV and AIDS in Malawi  [PDF]
Precious Madula, Yu Hong, Wellman Kondowe
Advances in Journalism and Communication (AJC) , 2017, DOI: 10.4236/ajc.2017.54016
Abstract: Radio programs are very important in developing countries in informing the masses about public health matters. Their role is quite visible in the fight against HIV/AIDS through dissemination of messages aimed at informing the publics about the dangers of HIV/AIDS and what prevention measures can be employed. Drawing on framing and social learning theory together with readings on media effects, this study aimed at establishing whether Pasimba radio program is having an impact in promoting behavioral change among couples in Malawi. Data was collected through a survey (N = 100) and data was analyzed using cross tabulations, chi-square, correlation and regression. Results indicate that there is a significant relationship between respondents who listen to the program and those that have the propensity to undergo HIV test. This implies that Pasimba program is having an impact in influencing behavioral change and that there is a correlation between listening to the program and having the motivation to know one’s serostatus.
Evaluation of Expression Stability of Candidate References Genes among Green and Yellow Pea Cultivars (Pisum sativum L.) Subjected to Abiotic and Biotic Stress  [PDF]
Gopesh C. Saha, George J. Vandemark
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.32028
Abstract: Dry pea (Pisum sativum L.) is grown as human and animal feed throughout the world. Large yield losses in pea due to biotic and abiotic stresses compel an improved understanding of mechanisms of stress tolerance and genetic determinants conditioning these tolerances. The availability of stably expressed reference genes is a prerequisite for examining differential gene expression. The objective of this study was to examine the expression profile of several candidate reference genes across a broad range of commercial pea cultivars. Expression profiles of five candidate reference genes; 18s rRNA, actin, TIF, β tubulin-2 and β tubulin-3 were examined. Relative quantifications of candidate reference genes were estimated from control plants, plants after 48 h of cold treatment, and plants 24 and 48 h after inoculation with Sclerotinia sclerotiorum, the causal agent of white mold disease of pea. RT-qPCR was performed on cDNA synthesized from three food grade spring peas, Ariel, Aragorn, and Sterling, and two spring yellow peas, Delta and Universal, which are used as animal feed. Analysis of variance (ANOVA) of CT values demonstrated significant variation between varieties and treatments under cold and disease conditions. The most abundant transcripts among tested reference genes were for 18s rRNA. Stability analysis indicated that TIF and β tubulin-3 genes were the most stably expressed candidate genes under both cold and disease stress and could serve as reference genes across a wide range of pea cultivars.
Investigation of the Force Transfer Mechanisms for Open Hoop FRP Strips Bonded on R/C Beams with or without Anchoring Devices  [PDF]
George C. Manos, Kostas V. Katakalos
Open Journal of Civil Engineering (OJCE) , 2013, DOI: 10.4236/ojce.2013.33017
Abstract:

The present study investigates the force transfer mechanisms for open hoop fiber reinforced plastic (FRP) strips attached at reinforced concrete (R/C) beams with or without anchorage. These open hoop FRP strips are utilized in R/C beams that are in need of shear capacity upgrade. This type of retrofitting is necessary for R/C structures designed with less stringent seismic loading conditions than those currently required. For this purpose special unit beam concrete specimens were fabricated and were used to attach open hoop carbon (CFRP) or steel (SFRP) FRP strips with or without anchoring. A novel loading arrangement was utilized to apply the necessary forces to these unit beam specimens together with instrumentation capable of capturing the behaviour of these specimens up to failure. Studying in this way the transfer of forces from the open hoop FRP strips, it could be demonstrated that when this type of retrofitting was accompanied with a properly designed anchoring device, a significant increase in the bearing capacity of the tested specimens was observed. Moreover, the observed failure was that of the fracture of the FRP strips for all such specimens. The highest degree of FRP material exploitation was achieved in the specimen that utilizes a patented anchoring device together with two layers of SFRP strips. Debonding of the FRP strips or failure of the anchoring device results, as was to be expected, in relatively unsatisfactory FRP material exploitation.

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