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Search Results: 1 - 10 of 405881 matches for " Jeffrey M Gidday "
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CCL2 upregulation triggers hypoxic preconditioning-induced protection from stroke
Ann M Stowe, Bradley K Wacker, Petra D Cravens, Jennifer L Perfater, Min K Li, Ruilong Hu, Angela B Freie, Olaf Stüve, Jeffrey M Gidday
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-33
Abstract: Adult male SW/ND4, CCL2-null, and wild-type mice were used in these studies. Cortical CCL2/CCR2 message, protein, and cell-type specific immunoreactivity were determined following HPC (4 h, 8% O2) or room air control (21% O2) from 6 h through 2 weeks following HPC. Circulating leukocyte subsets were determined by multi-parameter flow cytometry in na?ve mice and 12 h after HPC. CCL2-null and wild-type mice were exposed to HPC 2 days prior to tMCAo, with immunoneutralization of CCL2 during HPC achieved by a monoclonal CCL2 antibody.Cortical CCL2 mRNA and protein expression peaked at 12 h after HPC (both p < 0.01), predominantly in cortical neurons, and returned to baseline by 2 days. A delayed cerebral endothelial CCL2 message expression (p < 0.05) occurred 2 days after HPC. The levels of circulating monocytes (p < 0.0001), T lymphocytes (p < 0.0001), and granulocytes were decreased 12 h after HPC, and those of B lymphocytes were increased (p < 0.0001), but the magnitude of these respective changes did not differ between wild-type and CCL2-null mice. HPC did decrease the number of circulating CCR2+ monocytes (p < 0.0001) in a CCL2-dependent manner, but immunohistochemical analyses at this 12 h timepoint indicated that this leukocyte subpopulation did not move into the CNS. While HPC reduced infarct volumes by 27% (p < 0.01) in wild-type mice, CCL2-null mice subjected to tMCAo were not protected by HPC. Moreover, administration of a CCL2 immunoneutralizing antibody prior to HPC completely blocked (p < 0.0001 vs. HPC-treated mice) the development of ischemic tolerance.The early expression of CCL2 in neurons, the delayed expression of CCL2 in cerebral endothelial cells, and CCL2-mediated actions on circulating CCR2+ monocytes, appear to be required to establish ischemic tolerance to focal stroke in response to HPC, and thus represent a novel role for this chemokine in endogenous neurovascular protection.Preconditioning occurs when an organism, tissue, or cell is exposed
Automorphisms of Regular Wreath Product -Groups
Jeffrey M. Riedl
International Journal of Mathematics and Mathematical Sciences , 2009, DOI: 10.1155/2009/245617
Abstract: We present a useful new characterization of the automorphisms of the regular wreath product group of a finite cyclic -group by a finite cyclic -group, for any prime , and we discuss an application. We also present a short new proof, based on representationtheory, for determining the order of the automorphism group Aut(), where is the regular wreath product of a finite cyclic -group by an arbitrary finite -group.
Is there a Learning Curve for Pancreaticoduodenectomy after Fellowship Training?
Jeffrey M. Hardacre
HPB Surgery , 2010, DOI: 10.1155/2010/230287
Abstract: Background. Limited data exist regarding a learning curve for pancreaticoduodenectomy (PD). This study examines whether a learning curve exists for the performance of PD after fellowship training. Methods. Review of the outcomes of a single surgeon's first 60?PDs after completion of specialty training in pancreatic surgery. Results. Sixty?PDs were performed over five years, with the final 30 being done in the last 15 months. Patient age and gender did not differ between the first 30 and last 30 patients. When comparing the first 30?PDs to the second 30?PDs, significant improvements were found in operative time (463 versus 388 minutes), length of stay (10 versus 7 days), and receipt of adjuvant therapy (58% versus 91%). There were no significant differences found in mortality (7% versus 0%), complications (60% versus 50%), readmissions (18% versus 20%), or margin-positive resections (25% versus 24%). Conclusion. Even with extensive training in pancreatic surgery, a learning curve exists for the performance of PD. With experience, improvements were made in operative time, but more importantly in patient outcomes including length of stay and receipt of adjuvant therapy. 1. Introduction There is a growing literature about learning curves and the performance of advanced laparoscopic operations, such as fundoplication and colectomy [1, 2]. Open pancreaticoduodenectomy (PD) is a complex operation about which there are limited data regarding a learning curve. Tseng et al. examined the initial operative experiences with PD of three fellowship-trained surgeons [3]. They found that after 60 cases, each surgeon showed improvement with regard to estimated blood loss, operative time, length of stay, and achievement of margin-negative resections. They concluded that there was an “inherent learning curve” in the performance of pancreaticoduodenectomy. A question not answered by Tseng et al. is whether fewer than 60 PDs could be a threshold beyond which improvement is seen in the performance of PD by a fellowship-trained surgeon. This study examines the outcomes of a single surgeon’s first 60 PDs, assessing for changes over time. 2. Methods The Institutional Review Board of University Hospitals Case Medical Center approved this study. The medical records of a single surgeon’s first 60 pancreaticoduodenectomies were reviewed. During his chief resident year and an additional year of training in advanced gastrointestinal surgery, the surgeon performed 63 PDs, seven distal pancreatectomies, and five total pancreatectomies. The operations examined in this study occurred over
The Conflict within and the Escalating War between the Sex Chromosomes
Jeffrey M. Good
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002955
Abstract:
Calculation of the relative metastabilities of proteins using the CHNOSZ software package
Jeffrey M Dick
Geochemical Transactions , 2008, DOI: 10.1186/1467-4866-9-10
Abstract: A software package called CHNOSZ implementing the revised Helgeson-Kirkham-Flowers (HKF) equations of state and group additivity for ionized unfolded aqueous proteins was developed. The program can be used to calculate standard molal Gibbs energies and other thermodynamic properties of reactions and to make chemical speciation and predominance diagrams that represent the metastable equilibrium distributions of proteins. The approach takes account of the chemical affinities of reactions in open systems characterized by the chemical potentials of basis species. The thermodynamic database included with the package permits application of the software to mineral and other inorganic systems as well as systems of proteins or other biomolecules.Metastable equilibrium activity diagrams were generated for model cell-surface proteins from archaea and bacteria adapted to growth in environments that differ in temperature and chemical conditions. The predicted metastable equilibrium distributions of the proteins can be compared with the optimal growth temperatures of the organisms and with geochemical variables. The results suggest that a thermodynamic assessment of protein metastability may be useful for integrating bio- and geochemical observations.Owing to the growing body of compositional data for microbial proteins and the exploration of environments that are extreme from the human standpoint, it has become possible in recent years to draw correlations between the compositions of proteins and environmental parameters such as temperature [1]. Accounting for the underlying causes of the observed correlations between environmental parameters and protein composition is an ongoing challenge. Biochemical approaches are based in part on the notion that proteins from thermophilic and hyperthermophilic organisms should have greater structural stabilities than their mesophilic counterparts [2]. Compositional features of thermophilic proteins that may enhance their structural stabiliti
Effect of a proprietary intraluminal stiffening wire device on cecal intubation time and rate with used colonoscopes; a randomized, controlled trial
Jeffrey M East
BMC Research Notes , 2013, DOI: 10.1186/1756-0500-6-48
Abstract: A new intraluminal stiffening device has become available in two grades of stiffness. However, there is no published evidence of its effectiveness. This randomized, controlled trial was designed to determine the effectiveness of the stiffening wires in improving cecal intubation rate and time following routine application. A secondary analysis determines effectiveness of application only after intractable failure with the unaided colonoscope.The colonoscope tested was an Olympus CF-100TL, approximately fifteen years old. Patients were randomly assigned to the unaided colonoscope or the standard or firm wire introduced routinely on entry into transverse colon. Each phase of colonoscopy was timed. Failure to advance the colonoscope for 5?minutes (despite usual manipulations to minimize looping) required switching to another intervention according to a prescribed methodology and the originally assigned intervention was recorded as failed.The study was terminated after accrual of 112 participants (target sample size 480) because the colonoscope required repairs (no damage attributable to stiffening wires) which would have been uneconomical. There were no statistically significant differences between per-protocol cecal intubation rates (81.1, 71.1 and 70.3 percent respectively), a finding which persisted after multiple imputation for a virtual sample size of 480. Similarly, there were no statistically significant differences between per-protocol cecal intubation times (15, 16.2 and 13.9?minutes). However, a statistically significant improvement in cecal intubation rate (from 81.1% to 97.3%, P?=?0.0313) was achieved when the wires were applied after intractable failure of the unaided colonoscope in the first intervention group.Routine application of either stiffening wire does not improve caecal intubation rate nor time compared to the unaided colonoscope. However, application of the stiffening wires after intractable failure of the unaided colonoscope enabled a statistic
Calculation of the relative metastabilities of proteins in subcellular compartments of Saccharomyces cerevisiae
Jeffrey M Dick
BMC Systems Biology , 2009, DOI: 10.1186/1752-0509-3-75
Abstract: I adopt the hypothesis that the state of yeast subcellular organization is in a local energy minimum. This hypothesis implies that equilibrium thermodynamic models can yield predictions about the interdependence between populations of proteins and their subcellular chemical environments.Three types of tests are proposed. First, there should be correlations between modeled and observed oxidation states for different compartments. Second, there should be a correspondence between the energy requirements of protein formation and the order the appearance of organelles during cellular development. Third, there should be correlations between the predicted and observed relative abundances of interacting proteins within compartments.The relative metastability fields of subcellular homologs of glutaredoxin and thioredoxin indicate a trend from less to more oxidizing as mitochondrion – cytoplasm – nucleus. Representing the overall amino acid compositions of proteins in 23 different compartments each with a single reference model protein suggests that the formation reactions for proteins in the vacuole (in relatively oxidizing conditions), ER and early Golgi (in relatively reducing conditions) are relatively highly favored, while that for the microtubule is the most costly. The relative abundances of model proteins for each compartment inferred from experimental data were found in some cases to correlate with the predicted abundances, and both positive and negative correlations were found for some assemblages of proteins in known complexes.The results of these calculations and tests suggest that a tendency toward a metastable energy minimum could underlie some organizational links between the the chemical thermodynamic properties of proteins and subcellular chemical environments. Future models of this kind will benefit from consideration of additional thermodynamic variables together with more detailed subcellular observations.A complex interplay of chemical and biological forc
Gait variability: methods, modeling and meaning
Jeffrey M Hausdorff
Journal of NeuroEngineering and Rehabilitation , 2005, DOI: 10.1186/1743-0003-2-19
Abstract: Like most physiologic signals, measures of gait are not constants but rather fluctuate with time and change from one stride to the next, even when environmental and external conditions are fixed (Figure 1). In healthy adults, these stride-to-stride fluctuations are relatively small and the coefficient of variation of many gait parameters (e.g., gait speed, stride time) is on the order of just a few percent [1-3], testimony to the accuracy and reliability of the fine-tuned systems that regulate gait. Recently, the apparently "noisy" variations in stride length, stride time and gait speed have also been shown to display a hidden and unexpected fractal-like property [4-9]. These properties of gait exhibit long-range (power-law) correlations and a "memory" effect, such that fluctuations at any given moment are statistically related to those that occur over many different time scales. When the systems regulating gait are disturbed (e.g., as a result of certain diseases), movement control may be impaired leading to increased stride-to-stride fluctuations and/or alterations in their multiscale dynamics.The current series of the Journal of NeuroEngineering and Rehabilitation (JNER) is dedicated to gait variability. As guest editor of a collection of nine papers on this topic, I have had the opportunity to preview the wealth of information on stride-to-stride fluctuations in gait and the manifold ways in which gait variability may be analyzed. The articles in this collection cover a wide spectrum of themes ranging from methods for evaluating gait variability, animal and mathematical models investigating the factors that influence the variability of gait, and evaluations of the clinical utility of such measures. Altogether, these reports underscore the complex and fascinating nature of gait variability.To set the stage, it is helpful to briefly highlight previous work in this area. Earlier studies have demonstrated that:? Gait variability is a quantifiable feature of walking
Deluges of grandeur: Water, territory, and power on Northwest Mexico’s Río Mayo, 1880-1910
Jeffrey M. Banister
Water Alternatives , 2011,
Abstract: Northwest Mexico’s irrigation landscape, known today as El Distrito de Riego 038, or El Valle del Mayo, issues from historical struggles to build an official order out of a diverse world of signs, symbols, processes, places, and peoples. It is the ancestral home of the Yoreme (Mayo), an indigenous group for whom colonisation and agricultural development have meant the loss of autonomy and of the seasonal mobility required to subsist in an arid land. It is also the birthplace of President álvaro Obregón, a one-time chickpea farmer who transformed late-19th century irrigation praxis into the laws and institutions of 20th century water management. Reshaping territory for the ends of centralising ('federalising') water resources has always proved exceedingly difficult in the Mayo. But this was particularly so in the beginning of the federalisation process, a time of aggressive modernisation under the direction of President Porfirio Díaz (1876-1910). Research on Mexican hydraulic politics and policy, with some important exceptions, has tended to focus on the scale and scope of centralisation. Scholars have paid less attention to the moments and places where water escapes officials’ otherwise ironclad grasp. This paper explores water governance (and state formation more broadly) in the late 19th century, on the eve of Mexico’s 1910 Revolution, as an ongoing, ever-inchoate series of territorial claims and projects. Understanding the weaknesses and incompleteness of such projects offers critical insight into post-revolutionary and/or contemporary hydraulic politics.
Diluvios de grandeza: agua, territorio y poder en el río Mayo en el noroeste de México, 1880-1910
Jeffrey M. Banister
Región y sociedad , 2012,
Abstract: El actual distrito de riego 038 o valle del Mayo, que forma parte del espacio de riego del noroeste de México, surge de luchas históricas por construir un orden oficial en un mundo diverso de signos, símbolos, procesos, lugares y personas. Es el hogar ancestral de los yoremes (mayos), un grupo indígena para el que la colonización y el desarrollo agrícola han significado la pérdida de autonomía y de la movilidad estacional que requieren para subsistir en un terreno árido. Es el lugar donde nació el presidente álvaro Obregón, otrora productor de garbanzo, que transformó las prácticas de riego de fines del siglo xix en las leyes e instituciones para la administración del agua del siglo xx. Reconfigurar el territorio con el fin de centralizar ("federalizar") los recursos hídricos ha probado ser excesivamente difícil en la zona del Mayo, pero esto fue así en particular al inicio del proceso de federalización, una época de modernización dinámica bajo la dirección del presidente Porfirio Díaz (1876-1910). La investigación sobre la política hidráulica de México, con algunas importantes excepciones, ha tendido a enfocarse en la centraliza- ción. Los estudiosos le han prestado menor atención a los momentos y lugares en los que el agua escapa al control de las autoridades. Este trabajo explora la importancia de la administración del agua (y más ampliamente la formación del Estado) a finales del siglo xix, en vísperas de la Revolución Mexicana de 1910, como una serie continua, siempre incipiente de derechos y proyectos relativos a las tierras. Entender las debilidades e incompetencias de dichos proyectos ofrece un discernimiento crucial acerca de la política hidráulica posrevolucionaria o contemporánea.
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