102 research outputs found
Interleukin 1-β, Interleukin-1 Receptor Antagonist, and Interleukin 18 in Children with Acute Spontaneous Urticaria
Very little is known about the role of interleukin-1β (IL-1β) and interleukin-18 (IL-18) in urticaria. Material and Methods. Serum levels of IL-1β, IL-1 receptor antagonist (IL-1RA), and IL-18 were measured in 56 children with urticaria and in 41 healthy subjects. Results. Serum IL-1β did not differ between children with acute urticaria and controls. Children with single episode of urticaria had higher levels of IL-1RA and IL-18 than healthy subjects. In children with single episode of urticaria, level of IL-1RA correlated with C-reactive protein (CRP), D-dimer, and IL-1β levels. In subjects with recurrence of urticaria IL-1RA was positively correlated with WBC and D-dimer levels. No correlation of cytokine levels and urticaria severity scores (UAS) in all children with urticaria was observed. In children with single episode of urticaria UAS correlated with CRP level. In the group with single episode of urticaria and in children with symptoms of upper respiratory infection, IL-1RA and IL-18 levels were higher than in controls. The former was higher than in noninfected children with urticaria. In conclusion, this preliminary study documents that serum IL-1RA and IL-18 levels are increased in some children with acute urticaria. However further studies are necessary to define a pathogenic role of IL-1β, IL-1RA, and IL-18 in urticaria
The combinatorics of the Baer-Specker group
Denote the integers by Z and the positive integers by N.
The groups Z^k (k a natural number) are discrete, and the classification up
to isomorphism of their (topological) subgroups is trivial. But already for the
countably infinite power Z^N of Z, the situation is different. Here the product
topology is nontrivial, and the subgroups of Z^N make a rich source of examples
of non-isomorphic topological groups. Z^N is the Baer-Specker group.
We study subgroups of the Baer-Specker group which possess group theoretic
properties analogous to properties introduced by Menger (1924), Hurewicz
(1925), Rothberger (1938), and Scheepers (1996). The studied properties were
introduced independently by Ko\v{c}inac and Okunev. We obtain purely
combinatorial characterizations of these properties, and combine them with
other techniques to solve several questions of Babinkostova, Ko\v{c}inac, and
Scheepers.Comment: To appear in IJ
The dimension of the space of R-places of certain rational function fields
We prove that the space of -places of the field
of rational functions of two variables with coefficients in a totally
Archimedean field has covering and integral dimensions \dim
M(K(x,y))=\dim_\IZ M(K(x,y))=2 and the cohomological dimension for any Abelian 2-divisible coefficient group .Comment: 8 page
Some new directions in infinite-combinatorial topology
We give a light introduction to selection principles in topology, a young
subfield of infinite-combinatorial topology. Emphasis is put on the modern
approach to the problems it deals with. Recent results are described, and open
problems are stated. Some results which do not appear elsewhere are also
included, with proofs.Comment: Small update
Active Brownian Motion Models and Applications to Ratchets
We give an overview over recent studies on the model of Active Brownian
Motion (ABM) coupled to reservoirs providing free energy which may be converted
into kinetic energy of motion. First, we present an introduction to a general
concept of active Brownian particles which are capable to take up energy from
the source and transform part of it in order to perform various activities. In
the second part of our presentation we consider applications of ABM to ratchet
systems with different forms of differentiable potentials. Both analytical and
numerical evaluations are discussed for three cases of sinusoidal,
staircase-like and Mateos ratchet potentials, also with the additional loads
modeled by tilted potential structure. In addition, stochastic character of the
kinetics is investigated by considering perturbation by Gaussian white noise
which is shown to be responsible for driving the directionality of the
asymptotic flux in the ratchet. This \textit{stochastically driven
directionality} effect is visualized as a strong nonmonotonic dependence of the
statistics of the right versus left trajectories of motion leading to a net
current of particles. Possible applications of the ratchet systems to molecular
motors are also briefly discussedComment: 12 pages, 17 figure
Artificial Brownian motors: Controlling transport on the nanoscale
In systems possessing spatial or dynamical symmetry breaking, Brownian motion
combined with symmetric external input signals, deterministic or random, alike,
can assist directed motion of particles at the submicron scales. In such cases,
one speaks of "Brownian motors". In this review the constructive role of
Brownian motion is exemplified for various one-dimensional setups, mostly
inspired by the cell molecular machinery: working principles and
characteristics of stylized devices are discussed to show how fluctuations,
either thermal or extrinsic, can be used to control diffusive particle
transport. Recent experimental demonstrations of this concept are reviewed with
particular attention to transport in artificial nanopores and optical traps,
where single particle currents have been first measured. Much emphasis is given
to two- and three-dimensional devices containing many interacting particles of
one or more species; for this class of artificial motors, noise rectification
results also from the interplay of particle Brownian motion and geometric
constraints. Recently, selective control and optimization of the transport of
interacting colloidal particles and magnetic vortices have been successfully
achieved, thus leading to the new generation of microfluidic and
superconducting devices presented hereby. Another area with promising potential
for realization of artificial Brownian motors are microfluidic or granular
set-ups.....Comment: 57 pages, 39 figures; submitted to Reviews Modern Physics, revised
versio
Vanadium(IV) complexes with methyl-substituted 8-hydroxyquinolines : catalytic potential in the oxidation of hydrocarbons and alcohols with peroxides and biological activity
Methyl-substituted 8-hydroxyquinolines (Hquin) were successfully used to synthetize
five-coordinated oxovanadium(IV) complexes: [VO(2,6-(Me)2-quin)2] (1), [VO(2,5-(Me)2-quin)2] (2)
and [VO(2-Me-quin)2] (3). Complexes 1–3 demonstrated high catalytic activity in the oxidation of
hydrocarbons with H2O2 in acetonitrile at 50 C, in the presence of 2-pyrazinecarboxylic acid (PCA)
as a cocatalyst. The maximum yield of cyclohexane oxidation products attained was 48%, which is
high in the case of the oxidation of saturated hydrocarbons. The reaction leads to the formation of a
mixture of cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone. When triphenylphosphine is
added, cyclohexyl hydroperoxide is completely converted to cyclohexanol. Consideration of the regioand
bond-selectivity in the oxidation of n-heptane and methylcyclohexane, respectively, indicates
that the oxidation proceeds with the participation of free hydroxyl radicals. The complexes show
moderate activity in the oxidation of alcohols. Complexes 1 and 2 reduce the viability of colorectal
(HCT116) and ovarian (A2780) carcinoma cell lines and of normal dermal fibroblasts without showing
a specific selectivity for cancer cell lines. Complex 3 on the other hand, shows a higher cytotoxicity in
a colorectal carcinoma cell line (HCT116), a lower cytotoxicity towards normal dermal fibroblasts
and no effect in an ovarian carcinoma cell line (order of magnitude HCT116 > fibroblasts > A2780)
Jury Systems Around the World
Lay citizens participate as decision makers in the legal systems of many countries. This review describes the different approaches that countries employ to integrate lay decision makers, contrasting in particular the use of juries composed of all citizens with mixed decision-making bodies of lay and law-trained judges. The review discusses research on the benefits and drawbacks of lay legal decision making as well as international support for the use of ordinary citizens as legal decision makers, with an eye to explaining a recent increase in new jury systems around the world. The review calls for more comparative work on diverse approaches to lay participation, examining how different methods of including lay participation promote or detract from fact finding, legal consciousness, civic engagement, and citizen power
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