28 research outputs found
Disorder Induced Phases in Higher Spin Antiferromagnetic Heisenberg Chains
Extensive DMRG calculations for spin S=1/2 and S=3/2 disordered
antiferromagnetic Heisenberg chains show a rather distinct behavior in the two
cases. While at sufficiently strong disorder both systems are in a random
singlet phase, we show that weak disorder is an irrelevant perturbation for the
S=3/2 chain, contrary to what expected from a naive application of the Harris
criterion. The observed irrelevance is attributed to the presence of a new
correlation length due to enhanced end-to-end correlations. This phenomenon is
expected to occur for all half-integer S > 1/2 chains. A possible phase diagram
of the chain for generic S is also discussed.Comment: 6 Pages and 6 figures. Final version as publishe
Surface critical behavior of random systems at the ordinary transition
We calculate the surface critical exponents of the ordinary transition
occuring in semi-infinite, quenched dilute Ising-like systems. This is done by
applying the field theoretic approach directly in d=3 dimensions up to the
two-loop approximation, as well as in dimensions. At
we extend, up to the next-to-leading order, the previous
first-order results of the expansion by Ohno and Okabe
[Phys.Rev.B 46, 5917 (1992)]. In both cases the numerical estimates for surface
exponents are computed using Pade approximants extrapolating the perturbation
theory expansions. The obtained results indicate that the critical behavior of
semi-infinite systems with quenched bulk disorder is characterized by the new
set of surface critical exponents.Comment: 11 pages, 11 figure
The impact of circulating preeclampsia-associated extracellular vesicles on the migratory activity and phenotype of THP-1 monocytic cells
Intercellular communication via extracellular vesicles (EVs) and their target cells, especially immune cells, results in functional and phenotype changes that consequently may play a significant role in various physiological states and the pathogenesis of immune-mediated disorders. Monocytes are the most prominent environment-sensing immune cells in circulation, skilled to shape their microenvironments via cytokine secretion and further differentiation. Both the circulating monocyte subset distribution and the blood plasma EV pattern are characteristic for preeclampsia, a pregnancy induced immune-mediated hypertensive disorder. We hypothesized that preeclampsia-associated EVs (PE-EVs) induced functional and phenotypic alterations of monocytes. First, we proved EV binding and uptake by THP-1 cells. Cellular origin and protein cargo of circulating PE-EVs were characterized by flow cytometry and mass spectrometry. An altered phagocytosis-associated molecular pattern was found on 12.5 K fraction of PE-EVs: an elevated CD47 "don't eat me" signal (p < 0.01) and decreased exofacial phosphatidylserine "eat-me" signal (p < 0.001) were found along with decreased uptake of these PE-EVs (p < 0.05). The 12.5 K fraction of PE-EVs induced significantly lower chemotaxis (p < 0.01) and cell motility but accelerated cell adhesion of THP-1 cells (p < 0.05). The 12.5 K fraction of PE-EVs induced altered monocyte functions suggest that circulating EVs may have a role in the pathogenesis of preeclampsia