oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Advantages for controls imposed in a proper subset  [PDF]
Gengsheng Wang,Yashan Xu
Mathematics , 2012,
Abstract: In this paper, we study time optimal control problems for heat equations on $\Omega\times \mathbb{R}^+$. Two properties under consideration are the existence and the bang-bang properties of time optimal controls. It is proved that those two properties hold when controls are imposed on some proper subsets of $\Omega$; while they do not stand when controls are active on the whole $\Omega$. Besides, a new property for eigenfunctions of $-\Delta$ with Dirichlet boundary condition is revealed.
A proper motion study of the Lupus clouds using VO tools  [PDF]
Belén López Martí,Francisco Jiménez-Esteban,Enrique Solano
Physics , 2011, DOI: 10.1051/0004-6361/201016377
Abstract: Aims: By using kinematical information, we test the membership of the new Lupus candidate members proposed by the Cores to Disks (c2d) Spitzer Legacy Program program and by a complementary optical survey. We also investigate the relationship between the proper motions (pm) and other properties, in order to get some clues about their formation and early evolution. Methods: We compiled a list of members and possible members of Lupus 1, 3, and 4, together with all information on their spectral types, disks, and physical parameters. Using VO-tools, we cross-matched this list with the astrometric catalogues to get pm. Our final sample contains sources with magnitudes I<16mag and estimated masses >~0.1Msun. Results: According to the kinematic information, our sources can be divided into two main groups. The first one contains sources with higher pm in agreement with other Gould Belt populations and with spatial distribution, optical and near-infrared colours, and disk composition consistent with these objects belonging to the Lupus clouds. In the second group, sources have lower pm with random orientations, and they are mostly located outside the cloud cores, making their association with the Lupus complex more doubtful. We investigate the properties of the higher pm group, but cannot find any correlations with spatial location, binarity, the presence of a circumstellar disk, or with physical properties such as effective temperature, luminosity, mass, or age. Conclusions: We conclude that the lower pm group probably represents a background population or mixture of populations unrelated to the Lupus clouds. The higher pm group, on the other hand, has properties consistent with it being a genuine population of the Lupus star-forming region. More accurate pm and/or radial velocity information are required for a more detailed study of the kinematic properties of the Lupus stellar members.
Modulation of T Cell Function by Combination of Epitope Specific and Low Dose Anticytokine Therapy Controls Autoimmune Arthritis  [PDF]
Sarah T.A. Roord, Evelien Zonneveld-Huijssoon, Tho Le, Gisella Puga Yung, Eva Koffeman, Arash Ronaghy, Negar Ghahramani, Paola Lanza, Rosario Billetta, Berent J. Prakken, Salvatore Albani
PLOS ONE , 2006, DOI: 10.1371/journal.pone.0000087
Abstract: Innate and adaptive immunity contribute to the pathogenesis of autoimmune arthritis by generating and maintaining inflammation, which leads to tissue damage. Current biological therapies target innate immunity, eminently by interfering with single pro-inflammatory cytokine pathways. This approach has shown excellent efficacy in a good proportion of patients with Rheumatoid Arthritis (RA), but is limited by cost and side effects. Adaptive immunity, particularly T cells with a regulatory function, plays a fundamental role in controlling inflammation in physiologic conditions. A growing body of evidence suggests that modulation of T cell function is impaired in autoimmunity. Restoration of such function could be of significant therapeutic value. We have recently demonstrated that epitope-specific therapy can restore modulation of T cell function in RA patients. Here, we tested the hypothesis that a combination of anti-cytokine and epitope-specific immunotherapy may facilitate the control of autoimmune inflammation by generating active T cell regulation. This novel combination of mucosal tolerization to a pathogenic T cell epitope and single low dose anti-TNFα was as therapeutically effective as full dose anti-TNFα treatment. Analysis of the underlying immunological mechanisms showed induction of T cell immune deviation.
Fas-Independent T-Cell Apoptosis by Dendritic Cells Controls Autoimmune Arthritis in MRL/lpr Mice  [PDF]
Takashi Izawa, Tomoyuki Kondo, Mie Kurosawa, Ritsuko Oura, Kazuma Matsumoto, Eiji Tanaka, Akiko Yamada, Rieko Arakaki, Yasusei Kudo, Yoshio Hayashi, Naozumi Ishimaru
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048798
Abstract: Background Although autoimmunity in MRL/lpr mice occurs due to a defect in Fas-mediated cell death of T cells, the role of Fas-independent apoptosis in pathogenesis has rarely been investigated. We have recently reported that receptor activator of nuclear factor (NF)-κB ligand (RANKL)-activated dendritic cells (DCs) play a key role in the pathogenesis of rheumatoid arthritis (RA) in MRL/lpr mice. We here attempted to establish a new therapeutic strategy with RANKL-activated DCs in RA by controlling apoptosis of peripheral T cells. Repeated transfer of RANKL-activated DCs into MRL/lpr mice was tested to determine whether this had a therapeutic effect on autoimmunity. Methods and Finding Cellular and molecular mechanisms of Fas-independent apoptosis of T cells induced by the DCs were investigated by in vitro and in vivo analyses. We demonstrated that repeated transfers of RANKL-activated DCs into MRL/lpr mice resulted in therapeutic effects on RA lesions and lymphoproliferation due to declines of CD4+ T, B, and CD4?CD8? double negative (DN) T cells. We also found that the Fas-independent T-cell apoptosis was induced by a direct interaction between tumor necrosis factor (TNF)-related apoptosis-inducing ligand-receptor 2 (TRAIL-R2) on T cells and TRAIL on Fas-deficient DCs in MRL/lpr mice. Conclusion These results strongly suggest that a novel Fas-independent apoptosis pathway in T cells maintains peripheral tolerance and thus controls autoimmunity in MRL/lpr mice.
Epilepsy cases: fMRI and MR tractography as qualitative and quantitative tools for proper localization and pre-operative planning
Ahmed Abdelmoniem Gaber *,Azza M. Sarry El Din**,Eman A.Geneidi, *, Mohamed KhMitkees, *,Wael Abdelhalim Reda, **and Yasser A Abbas
Egyptian Journal of Hospital Medicine , 2012,
Abstract: Introduction: Functional MRI is a relatively new noninvasive brain imaging technique that has been used for neuroscience research applications since the early 1990s. This technique relies on the blood oxygenation level dependent (BOLD) effect. Diffusion tensor magnetic resonance imaging (DTI) is a noninvasive technique that can be used to assess the integrity of cerebral tissue. Methods: We evaluated 16 patients with unilateral MTLE. We did MRI for language and memory areas for localization and lateralization of the dominating cortical areas concerned with language and memory. Diffusion-weighted images along twelve different directions with a b value of 1000 s/mm2. A 1.5-T scanner was used to acquire those examinations. For DTI we compared the mean diffusivity (MD) and fractional anisotropy (FA) from symmetrical voxels by sampling the basal ganglia, thalamus, hippocampus and parahippocampus regions bilaterally. We compared measurements with the EEG, high-resolution MR imaging, as well as clinical data. For MR tractography, various tracts were traced including the Meyer’s loop.Results: Among the study group only 5 patients with partial epilepsy out of 16 are promising candidates for surgery representing only 31.25 % among the study population 68.75% of our study population were excluded according to our quantitative and qualitative tools.Conclusion: Combined fMRI with MR tractography are valuable qualitative and quantitative tools for proper localization and lateralization of the eloquent areas including memory, language areas and Meyer’s loop in the selection of promising epilepsy surgery candidates and for pre-operative planning.
Spectral measures and mixed models as valuable tools for investigating controls on land surface phenology in high arctic Greenland
Mikkel P Tamstorf, Lotte Illeris, Birger U Hansen, Mary Wisz
BMC Ecology , 2007, DOI: 10.1186/1472-6785-7-9
Abstract: Snow melt and temperature are of major importance for the timing of the maximum growth as well as for the seasonal growth. More than 85% of the variance in timing of the maximum growth is explained by the models and similar for the seasonal growth of mesic and wet vegetation types. We find several non-linear growth responses to the environmental variables.We conclude that the uses of GAMMs are valuable for investigating growth dynamics in the Arctic. Contrary to several other studies in the Arctic we found a significant decreasing trend of the seasonally integrated NDVI-FR (SINDVI) in some vegetation types. This indicates that although greening might occur wide-spread in the Arctic there are variations on the local scale that might influence the regional trends on the longer term.Land surface phenology is a key variables for modelling of the terrestrial ecosystems in a global change perspective and as such as input into circulation models (GCM's) [1]. Recent models agree that changes in vegetation and soil processes will have net positive feedback on future global warming [2]. Further, the way terrestrial ecology is implemented in GCM's will have a strong impact on the ability to predict future climatic changes [3] and knowledge of changes in the vegetation cover and the reasons for these are therefore of major importance. This has led to a number of publications and assessments on the greening and impact of global climate change in northern high latitudes [4-6] based on monitoring studies [7] and experimental studies [8,9]. Several of these studies have investigated the effect of temperature, light and fertilization on photosynthesis [10,11] and found that fertilization and increased temperatures significantly increases the photosynthesis while shading decreases the photosynthesis. Thawing degree-days and time of snow cover melt was found as the dominating controls on the phenology in the Subarctic [12]. Recently, Walker et al. included warming experiments from 11
IFN-gamma signaling in the central nervous system controls the course of experimental autoimmune encephalomyelitis independently of the localization and composition of inflammatory foci
Eunyoung Lee, Sarah Chanamara, David Pleasure, Athena M Soulika
Journal of Neuroinflammation , 2012, DOI: 10.1186/1742-2094-9-7
Abstract: We induced EAE in IFNγ-/- mice and bone marrow chimeric mice in which IFNγR is not expressed in the CNS but is intact in the periphery (IFNγRCNSKO) and vice versa (IFNγRperiKO). Blood-brain barrier permeability was determined by Evans blue intravenous administration at disease onset. Populations of immune cell subsets in the periphery and the CNS were quantified by flow cytometry. CNS tissues isolated at various time points after EAE induction, were analyzed by immunohistochemistry for composition of inflammatory foci and patterns of axonal degeneration.Incidence and severity of atypical EAE were more pronounced in IFNγRCNSKO as compared to IFNγRperiKO mice. Contrary to what we anticipated, cerebella/brainstems of IFNγRCNSKO mice were only minimally infiltrated, while the same areas of IFNγRperiKO mice were extensively populated by peripheral immune cells. Furthermore, the CNS of IFNγRperiKO mice was characterized by persistent neutrophil-rich foci as compared to IFNγRCNSKO. Immunohistochemical analysis of the CNS of IFNγ-/- and IFNγR chimeric mice revealed that IFNγ protective actions are exerted through microglial STAT1.Alterations in distribution and composition of CNS inflammatory foci are not sufficient for the onset of atypical EAE. IFNγ dictates the course of neuroinflammatory disorders mainly through actions exerted within the CNS. This study provides strong evidence that link microglial STAT1 inactivation to vestibular dysfunction.Experimental autoimmune encephalomyelitis (EAE) is the most commonly used animal model for multiple sclerosis (MS). Similar to MS, animals with EAE exhibit activation of immune cells in peripheral immune organs, migration of these cells into the CNS, and establishment of multifocal inflammation, demyelination and damage to neurons and axons. Cumulative axonal loss eventually leads to severe and permanent neurological deficits [1,2]. In classical EAE, most neurological deficits are attributable to spinal cord lesions. Interestingly
Alteration of transcriptomic networks in adoptive-transfer experimental autoimmune encephalomyelitis  [PDF]
Dumitru A. Iacobas,Sanda Iacobas,Peter Werner,ElianaScemes,David C. Spray
Frontiers in Integrative Neuroscience , 2007, DOI: 10.3389/neuro.07.010.2007
Abstract: Adoptive transfer experimental autoimmune encephalomyelitis (AT-EAE) is an inflammatory demyelination that recapitulates in mouse spinal cord (SC) the human multiple sclerosis disease. We now analyze previously reported cDNA array data from age-matched young female adult control and passively myelin antigen-sensitized EAE mice with regard to organizational principles of the SC transcriptome in autoimmune demyelination. Although AT-EAE had a large impact on immune response genes, broader functional and chromosomal gene cohorts were neither significantly regulated nor showed significant changes in expression coordination. However, overall transcriptional control was increased in AT-EAE and the proportions of transcript abundances were perturbed within each cohort. Striking likenesses and oppositions were identified in the coordination profiles of genes related to myelination, calcium signaling, and inflammatory response in controls that were substantially altered in AT-EAE. We propose that up- or down-regulation of genes linked to those targeted by the disease could potentially compensate for the pathological transcriptomic changes.
Identification of blue high proper motion objects in the Tycho-2 and 2MASS catalogues using Virtual Observatory tools  [PDF]
F. M. Jiménez-Esteban,J. A. Caballero,E. Solano
Physics , 2010, DOI: 10.1051/0004-6361/201015223
Abstract: With available Virtual Observatory tools, we looked for new bright blue high proper motion objects in the entire sky: white dwarfs, hot subdwarfs, runaway OB stars, and early-type stars in nearby young moving groups. We performed an all-sky cross-match between the optical Tycho-2 and near-infrared 2MASS catalogues with Aladin, and selected objects with proper motions >50mas/yr and colours Vt-Ks<-0.5mag with TOPCAT. We also collected multi-wavelength photometry, constructed the spectral energy distributions and estimated effective temperatures from fits to atmospheric models with VOSA for the most interesting targets. We assembled a sample of 32 bright blue high proper motion objects, including ten sdO/B subdwarfs, nine DA white dwarfs, five young early-type stars (two of which are runaway stars), two blue horizontal branch stars, one star with poor information, and five objects reported for the first time in this work. These last five objects have magnitudes Bt~11.0-11.6mag, effective temperatures ~24,000-30,000K, and are located in the region of known white dwarfs and hot subdwarfs in a reduced proper motion-colour diagram. We confirmed the hot subdwarf nature of one of the new objects, Albus 5, with public far-ultraviolet spectroscopic data obtained with FUSE.
Identification of red high proper-motion objects in Tycho-2 and 2MASS catalogues using Virtual Observatory tools  [PDF]
F. M. Jiménez-Esteban,J. A. Caballero,R. Dorda,P. A. Miles-Páez,E. Solano
Physics , 2012, DOI: 10.1051/0004-6361/201118375
Abstract: Aims: With available Virtual Observatory tools, we looked for new M dwarfs in the solar neighbourhood and M giants with high tangential velocities. Methods: From an all-sky cross-match between the optical Tycho-2 and the near-infrared 2MASS catalogues, we selected objects with proper motions >50mas/yr and very red V-Ks colours. For the most interesting targets, we collected multi-wavelength photometry, constructed spectral energy distributions, estimated effective temperatures and surface gravities from fits to atmospheric models, performed time-series analysis of ASAS V-band light curves, and assigned spectral types from low-resolution spectroscopy obtained with CAFOS at the 2.2m Calar Alto telescope. Results: We got a sample of 59 bright red high proper-motion objects, including fifty red giants, four red dwarfs, and five objects reported in this work for the first time. The five new stars have magnitudes V~10.8-11.3mag, reduced proper motions midway between known dwarfs and giants, near-infrared colours typical of giants, and effective temperatures Teff~2900-3400K. From our time-series analysis, we discovered a long secondary period in Ruber 4 and an extremely long primary period in Ruber 6. With the CAFOS spectra, we confirmed the red giant nature of Ruber 7 and 8, the last of which seems to be one of the brightest metal-poor M giants ever identified.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.