34 research outputs found
Thermal conductivity of tin-doped bismuth between 50 mK and 7K
The authors report on the thermal conductivity of tin-doped bismuth between 50 mK and 27K. A quantitative interpretation of the data is presented. At the lowest temperatures the electronic thermal conductivity dominates, but above 0.1K lattice waves carry most of the heat. Below 1K phonons are scattered mostly by crystal boundaries, while near the dielectric maximum point defects are important. Their scattering rate is directly proportional to the atomic concentration of the tin impurity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48999/2/jcv18i15p3001.pd
Functional Improvement of Regulatory T Cells From Rheumatoid Arthritis Subjects Induced by Capsular Polysaccharide Glucuronoxylomannogalactan
Objective: Regulatory T cells (Treg) play a critical role in the prevention of autoimmunity, and the suppressive activity of these cells is impaired in rheumatoid arthritis (RA). The aim of the present study was to investigate function and properties of Treg of RA patients in response to purified polysaccharide glucuronoxylomannogalactan (GXMGal). Methods: Flow cytometry and western blot analysis were used to investigate the frequency, function and properties of Treg cells. Results: GXMGal was able to: i) induce strong increase of FOXP3 on CD4+ T cells without affecting the number of CD4+CD25+FOXP3+ Treg cells with parallel increase in the percentage of non-conventional CD4+CD25-FOXP3+ Treg cells; ii) increase intracellular levels of TGF-beta1 in CD4+CD25-FOXP3+ Treg cells and of IL-10 in both CD4+CD25+FOXP3+ and CD4+CD25-FOXP3+ Treg cells; iii) enhance the suppressive activity of CD4+CD25+FOXP3+ and CD4+CD25-FOXP3+ Treg cells in terms of inhibition of effector T cell activity and increased secretion of IL-10; iv) decrease Th1 response as demonstrated by inhibition of T-bet activation and down-regulation of IFN-gamma and IL-12p70 production; v) decrease Th17 differentiation by down-regulating pSTAT3 activation and IL-17A, IL-23, IL-21, IL-22 and IL-6 production. Conclusion: These data show that GXMGal improves Treg functions and increases the number and function of CD4+CD25-FOXP3+ Treg cells of RA patients. It is suggested that GXMGal may be potentially useful for restoring impaired Treg functions in autoimmune disorders and for developing Treg cell-based strategies for the treatment of these diseases
Expansion of CD4+CD25+ and CD25- T-Bet, GATA-3, Foxp3 and RORÎłt Cells in Allergic Inflammation, Local Lung Distribution and Chemokine Gene Expression
Allergic asthma is associated with airway eosinophilia, which is regulated by
different T-effector cells. T cells express transcription factors T-bet, GATA-3,
RORÎłt and Foxp3, representing Th1, Th2, Th17 and Treg cells respectively. No
study has directly determined the relative presence of each of these T cell
subsets concomitantly in a model of allergic airway inflammation. In this study
we determined the degree of expansion of these T cell subsets, in the lungs of
allergen challenged mice. Cell proliferation was determined by incorporation of
5-bromo-2′-deoxyuridine (BrdU) together with 7-aminoactnomycin (7-AAD).
The immunohistochemical localisation of T cells in the lung microenvironments
was also quantified. Local expression of cytokines, chemokines and receptor
genes was measured using real-time RT-PCR array analysis in tissue sections
isolated by laser microdissection and pressure catapulting technology. Allergen
exposure increased the numbers of T-bet+,
GATA-3+, RORÎłt+ and
Foxp3+ cells in CD4+CD25+
and CD4+CD25- T cells, with the greatest expansion of
GATA-3+ cells. The majority of
CD4+CD25+ T-bet+,
GATA-3+, RORÎłt+ and
Foxp3+ cells had incorporated BrdU and underwent
proliferation during allergen exposure. Allergen exposure led to the
accumulation of T-bet+, GATA-3+ and
Foxp3+ cells in peribronchial and alveolar tissue,
GATA-3+ and Foxp3+ cells in perivascular
tissue, and RORÎłt+ cells in alveolar tissue. A total of 28
cytokines, chemokines and receptor genes were altered more than 3 fold upon
allergen exposure, with expression of half of the genes claimed in all three
microenvironments. Our study shows that allergen exposure affects all T effector
cells in lung, with a dominant of Th2 cells, but with different local cell
distribution, probably due to a distinguished local inflammatory milieu
Deux exemples de mélange par brassage mécanique entre laves alcalines contrastées dans le strato-volcan du Cantal (Massif Central Français). Implications volcanologiques
Resonant relaxation time for impurity electron -phonon interaction. Application to the thermal conductivity of MgO:Fe2+ and ZnS:Fe2+
Immunological Hallmarks of JC Virus Replication in Multiple Sclerosis Patients on Long-Term Natalizumab Therapy
Review of Pedro CalderĂłn de la Barca, CĂ©falo y Pocris, introd. Enrica Cancelliere, ed. Ignacio Arellano, New York, IDEA, 2013, 190 pp. ISBN 978-1-938795-93-
Acoustic and thermal transport properties of hard carbon formed from C
We report on extended investigation of the thermal transport and acoustical
properties on hard carbon samples obtained by pressurization of C60 fullerene.
Structural investigations performed by different techniques on the same samples
indicate a very inhomogeneous structure at different scales, based on
fractal-like amorphous clusters on the micrometer to submillimetre scale, which
act as strong acoustic scatterers, and scarce microcrystallites on the
nanometer scale. Ultrasonic experiments show a rapid increase in the
attenuation with frequency, corresponding to a decrease in the localization
length for vibrations. The data give evidence for a crossover from extended
phonon excitations to localized fracton excitations. The thermal conductivity
is characterized by a monotonous increase versus temperature, power law
T^(1.4), for T ranging from 0.1 to 10 K, without any well-defined plateau, and
a strictly linear-in-T variation between 20 and 300K. The latter has to be
related to the linear-in-T decrease of the sound velocity between 4 and 100 K,
both linear regimes being characteristic of disordered or generally aperiodic
structures, which can be analysed by the "phonon-fracton hopping" model
developed for fractal and amorphous structures.Comment: 30 pages, 8 EPS figures, 4 JPG picture