1,721,026 research outputs found
Inducing oscillations of trapped particles in a near-critical Gaussian field
No full textWe study the nonequilibrium dynamics of two particles confined in two
spatially separated harmonic potentials and linearly coupled to the same
thermally fluctuating scalar field, a cartoon for optically trapped
colloids in contact with a medium close to a continuous phase
transition. When an external periodic driving is applied to one of these
particles, a nonequilibrium periodic state is eventually reached in
which their motion synchronizes thanks to the field-mediated effective
interaction, a phenomenon already observed in experiments. We fully
characterize the nonlinear response of the second particle as a function
of the driving frequency, in particular far from the adiabatic regime in
which the field can be assumed to relax instantaneously. We compare the
perturbative, analytic solution to its adiabatic approximation, thus
determining the limits of validity of the latter, and we qualitatively
test our predictions against numerical simulations
Tracer particle in a confined correlated medium: an adiabatic elimination method
No full textWe present a simple and systematic procedure to determine the effective dynamics of a Brownian particle coupled to a rapidly fluctuating correlated medium, modeled as a scalar Gaussian field, under spatial confinement. The method allows us, in particular, to address the case in which the fluctuations of the medium are suppressed in the vicinity of the particle, as described by a quadratic coupling in the underlying Hamiltonian. As a consequence of the confinement of the correlated medium, the resulting effective Fokker-Planck equation features spatially dependent drift and diffusion coefficients. We apply our method to simplified fluid models of binary mixtures and microemulsions near criticality containing a colloidal particle, and we analyze the corrections to the stationary distribution of the particle position and the diffusion coefficient
Novel insights in the management of sickle cell disease in childhood.
Full text linkSickle cell disease (SCD) is a life-threatening genetic disorder characterized by chronic hemolytic anemia, vascular injury and multiorgan dysfunctions. Over the last few decades, there have been significant improvements in SCD management in Western countries, especially in pediatric population. An early onset of prophylaxis with Penicillin and a proper treatment of the infections have increased the overall survival in childhood. Nevertheless, management of painful episodes and prevention of organ damage are still challenging and more efforts are needed to better understand the mechanisms behind the development of chronic organ damages. Hydroxyurea (Hydroxycarbamide, HU), the only medication approved as a disease-modifying agent by the United States Food and Drug Administration and the European Medicines Agency, is usually under-used, especially in developing countries. Currently, hematopoietic stem-cell transplantation is considered the only curative option, although its use is limited by lack of donors and transplant-related toxicity. SCD symptoms are similar in children and adults, but complications and systemic organ damages increase with age, leading to early mortality worldwide. Experts in comprehensive care of young patients with SCD, especially those approaching the transition age to adulthood, are missing, leading people to rely on urgent care, increasing health care utilization costs and inappropriate treatments. It would be important to establish programs of comprehensive healthcare for patients with SCD from birth to adulthood, to improve their quality and expectancy of life
Inhibition of T-cell proliferation by a MYB antisense oligomer is accompanied by selective down-regulation of DNA polymerase alpha expression.
No full textWe recently found that inhibition of MYB protein synthesis in human peripheral blood mononuclear cells (PBMC) exposed to human c-myb (designated MYB) antisense oligodeoxynucleotides prevents entry into S phase and cell proliferation. To determine the mechanism(s) by which down-regulation of human c-myb protein (MYB) synthesis interferes with DNA synthesis, we analyzed mRNA levels of DNA polymerase alpha and proliferating cell nuclear antigen (PCNA), transcripts of two genes required for DNA synthesis, in normal and leukemic T lymphocytes exposed to MYB antisense oligodeoxynucleotides. Expression of DNA polymerase alpha was inhibited both in normal T lymphocytes progressing from G0 to S phase and in exponentially growing CCRF-CEM leukemic cells, whereas expression of PCNA was inhibited only in mitogen-stimulated PBMC and remained essentially unaffected in the leukemia T-cell line. The functional link between expression of MYB and DNA polymerase alpha mRNAs was further demonstrated by analyzing DNA polymerase alpha mRNA levels in a temperature-sensitive (ts) fibroblast cell line (TK-ts13; TK is thymidine kinase) constitutively expressing human MYB mRNA driven by the simian virus 40 (SV40) promoter. In the MYB-expressing TK-ts13 cells, DNA polymerase alpha mRNA levels were unaffected following shift to the nonpermissive temperature of 39.6 degrees C, whereas in the parental line, DNA polymerase alpha mRNA levels were readily down-regulated. These findings indicate that the expression of MYB is related to that of DNA polymerase alpha in cells expressing MYB at high levels and suggest that there is a functional link between c-myb and DNA polymerase alpha mRNA expression during cell cycle progression of normal T lymphocytes
Functional significance of c-myb expression in normal and leukemic hematopoiesis.
No full textNo abstract available
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
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
Recycling in ceramic glazes of zirconia overspray from thermal barrier coatings manufacturing
No full textGlazed ceramic tiles are the most common building material for floor and wall covering. Glazes are produced from frits. The aim of this work is to make a total or partial replacement of a raw material, zircon, widely used in ceramic tiles manufacturing, with a waste material, in order to prepare ceramic frits. The waste material used in this work, is the overspray zirconia, which is produced during the deposition process by atmospheric plasma spraying (APS) of thermal barrier coatings (TBC) on turbine blades. In particular, a replacement of 100. wt%, 1. wt% and 0.2. wt% of zirconium silicate with zirconia has been studied. Ceramic glazes prepared mixing frits and other raw materials are applied on a single-fired tile. The glazes obtained were characterized with different analytical techniques. This study has revealed that the substitution of zircon with waste zirconia is possible in small percentages due to the presence of small amount of chromophore ions in the overspray zirconia, which tend to colour the glaze
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