75 research outputs found
Attractors for Navier-Stokes flows with multivalued and nonmonotone subdifferential boundary conditions
We consider two-dimensional nonstationary Navier-Stokes shear flow with
multivalued and nonmonotone boundary conditions on a part of the boundary of
the flow domain. We prove the existence of global in time solutions of the
considered problem which is governed by a partial differential inclusion with a
multivalued term in the form of Clarke subdifferential. Then we prove the
existence of a trajectory attractor and a weak global attractor for the
associated multivalued semiflow. This research is motivated by control problems
for fluid flows in domains with semipermeable walls and membranes.Comment: A correction was introduced in assertion (ii) of Definition 4.4 and -
accordingly - in the proof of Theorem 4.
Global attractors for multivalued semiflows with weak continuity properties
A method is proposed to deal with some multivalued semiflows with weak
continuity properties. An application to the reaction-diffusion problems with
nonmonotone multivalued semilinear boundary condition and nonmonotone
multivalued semilinear source term is presented.Comment: to appear in Nonlinear Analysis Series A, Theory, Methods &
Application
Random attractors for stochastic 2D-Navier-Stokes equations in some unbounded domains
We show that the stochastic flow generated by the Stochastic Navier-Stokes
equations in a 2-dimensional Poincar\'e domain has a unique random attractor.
This result complements a recent result by Brze\'zniak and Li [10] who showed
that the flow is asymptotically compact and generalizes a recent result by
Caraballo et al. [12] who proved existence of a unique pullback attractor for
the time-dependent deterministic Navier-Stokes equations in a 2-dimensional
Poincar\'e domain
A synthesis of bacterial and archaeal phenotypic trait data
A synthesis of phenotypic and quantitative genomic traits is provided for bacteria and archaea, in the form of a scripted, reproducible workflow that standardizes and merges 26 sources. The resulting unified dataset covers 14 phenotypic traits, 5 quantitative genomic traits, and 4 environmental characteristics for approximately 170,000 strain-level and 15,000 species-aggregated records. It spans all habitats including soils, marine and fresh waters and sediments, host-associated and thermal. Trait data can find use in clarifying major dimensions of ecological strategy variation across species. They can also be used in conjunction with species and abundance sampling to characterize trait mixtures in communities and responses of traits along environmental gradients
Capric Acid Secreted by S. boulardii Inhibits C. albicans Filamentous Growth, Adhesion and Biofilm Formation
Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation
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