202 research outputs found
Numerical Schemes for Multivalued Backward Stochastic Differential Systems
We define some approximation schemes for different kinds of generalized
backward stochastic differential systems, considered in the Markovian
framework. We propose a mixed approximation scheme for a decoupled system of
forward reflected SDE and backward stochastic variational inequality. We use an
Euler scheme type, combined with Yosida approximation techniques.Comment: 13 page
Diffusion Process in a Flow
We establish circumstances under which the dispersion of passive contaminants
in a forced, deterministic or random, flow can be consistently interpreted as a
Markovian diffusion process. In case of conservative forcing the repulsive case
only, with bounded from below, is
unquestionably admitted by the compatibility conditions. A class of diffusion
processes is exemplified, such that the attractive forcing is allowed as well,
due to an appropriate compensation coming from the "pressure" term. The
compressible Euler flows form their subclass, when regarded as stochastic
processes. We establish circumstances under which the dispersion of passive
contaminants in a forced, deterministic or random, flow can be consistently
interpreted as a Markovian diffusion process. In case of conservative forcing
the repulsive case only, with bounded
from below, is unquestionably admitted by the compatibility conditions. A class
of diffusion processes is exemplified, such that the attractive forcing is
allowed as well, due to an appropriate compensation coming from the "pressure"
term. The compressible Euler flows form their subclass, when regarded as
stochastic processes.Comment: 10 pages, Late
Broken symmetries and directed collective energy transport
We study the appearance of directed energy current in homogeneous spatially
extended systems coupled to a heat bath in the presence of an external ac field
E(t). The systems are described by nonlinear field equations. By making use of
a symmetry analysis we predict the right choice of E(t) and obtain directed
energy transport for systems with a nonzero topological charge Q. We
demonstrate that the symmetry properties of motion of topological solitons
(kinks and antikinks) are equivalent to the ones for the energy current.
Numerical simulations confirm the predictions of the symmetry analysis and,
moreover, show that the directed energy current drastically increases as the
dissipation parameter reduces. Our results generalize recent rigorous
theories of currents generated by broken time-space symmetries to the case of
interacting many-particle systems.Comment: 4 pages, 2 figure
Driven diffusion in a periodically compartmentalized tube: homogeneity versus intermittency of particle motion
We study the effect of a driving force F on drift and diffusion of a point Brownian particle in a tube formed by identical ylindrical compartments, which create periodic entropy barriers for the particle motion along the tube axis. The particle transport exhibits striking features: the effective mobility monotonically decreases with increasing F, and the effective diffusivity diverges as F → ∞, which indicates that the entropic effects in diffusive transport are enhanced by the driving force. Our consideration is based on two different scenarios of the particle motion at small and large F, homogeneous and intermittent, respectively. The scenarios are deduced from the careful analysis of statistics of the particle transition times between neighboring openings. From this qualitative picture, the limiting small-F and large-F behaviors of the effective mobility and diffusivity are derived analytically. Brownian dynamics simulations are used to find these quantities at intermediate values of the driving force for various compartment lengths and opening radii. This work shows that the driving force may lead to qualitatively different anomalous transport features, depending on the geometry design
O FARMACEUTICO NO CONTEXTO DA ESTRATÉGIA EM SAÚDE DA FAMÍLIA, QUE REALIDADE É ESTA?
The present article reports the pharmacist’s experience on primary health attention, in the context of Brazilian family health strategy. It shows the path to his insertion in the health units, discusses where and how this pharmacist can act in this new proposal and the possible approaches on collective health field. It also brings a reflection about the difficulties during the period of Residence on health family units, the needs of professional education and the different meanings of the medicine to the patient, as well as the integrated work with the multiprofessional team, specially medicine and nutrition.Keywords: pharmacist; family health strategy; health unit.O presente artigo relata a experiência do profissional farmacêutico no âmbito da Atenção Primária, no contexto da Estratégia de Saúde da Família (ESF). Resgata seu histórico até a sua inserção em uma unidade de saúde, discute onde se insere o farmacêutico na proposta de transitoriedade do perfil da assistência e as possíveis abordagens dentro do campo da saúde coletiva. Aponta as dificuldades encontradas durante o período de residência em Unidades de Saúde da Família (USF), as necessidades na formação desse profissional para atuar na Atenção Primária à Saúde e, as diferentes configurações que o medicamento assume perante o indivíduo, bem como o trabalho integrado à equipe multiprofissional, em especial ao profissional médico e ao nutricionista
Organometallic iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis
Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands
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