95 research outputs found

    Asymptotic Stability for a Class of Metriplectic Systems

    Full text link
    Using the framework of metriplectic systems on Rn\R^n we will describe a constructive geometric method to add a dissipation term to a Hamilton-Poisson system such that any solution starting in a neighborhood of a nonlinear stable equilibrium converges towards a certain invariant set. The dissipation term depends only on the Hamiltonian function and the Casimir functions

    Dynamics of semi-flexible polymer solutions in the highly entangled regime

    Full text link
    We present experimental evidence that the effective medium approximation (EMA), developed by D.C. Morse [Phys. Rev. E {\bf 63}, 031502, (2001)], provides the correct scaling law of the macroscopic plateau modulus G0ρ4/3Lp1/3G^{0}\propto\rho^{4/3}L^{-1/3}_{p} (where ρ\rho is the contour length per unit volume and LpL_{p} is the persistence length) of semi-flexible polymer solutions, in the highly entangled concentration regime. Competing theories, including a self-consistent binary collision approximation (BCA), have instead predicted G0ρ7/5Lp1/5G^{0}\propto\rho^{7/5}L^{-1/5}_{p}. We have tested both the EMA and BCA scaling predictions using actin filament (F-actin) solutions which permit experimental control of LpL_p independently of other parameters. A combination of passive video particle tracking microrheology and dynamic light scattering yields independent measurements of the elastic modulus GG and LpL_{p} respectively. Thus we can distinguish between the two proposed laws, in contrast to previous experimental studies, which focus on the (less discriminating) concentration functionality of GG.Comment: 4 pages, 6 figures, Phys. Rev. Lett. (accepted

    The Many Faces of Long Noncoding RNAs in Cancer

    Get PDF
    SIGNIFICANCE: The emerging connections between an increasing number of long noncoding RNAs (lncRNAs) and oncogenic hallmarks provide a new twist to tumor complexity. Recent Advances: In the present review, we highlight specific lncRNAs that have been studied in relation to tumorigenesis, either as participants in the neoplastic process or as markers of pathway activity or drug response. These transcripts are typically deregulated by oncogenic or tumor-suppressing signals or respond to microenvironmental conditions such as hypoxia. CRITICAL ISSUES: Among these transcripts are lncRNAs sufficiently divergent between mouse and human genomes that may contribute to biological differences between species. FUTURE DIRECTIONS: From a translational standpoint, knowledge about primate-specific lncRNAs may help explain the reason behind the failure to reproduce the results from mouse cancer models in human cell-based systems. Antioxid. Redox Signal. 29, 922-935

    Collation of Scientific Evidence on Consumer Acceptance of New Food Technologies: Three roads to consumer choice

    Get PDF
    The current report investigates consumer acceptance of new food technologies by reviewing the scientific literature. The review is organised along three routes to consumer acceptance of new technologies: The consumer benefit road: the central road of technology features influencing experienced product attributes; the technology apprehension road: a socio-political road where unfamiliarity and dread may lead to negative technology attitudes, which may create categorical rejection of any product created with that technology; and the retail/caterer service road: where novel technologies does not directly influence perceived product characteristics, but results in novel retail and caterer business models, product placement and customer relation services. The available literature on 4 types of novel food technologies Mild processing technologies; Electromagnetic methods; Texturizing technologies; and Novel packaging and storage technologies is reviewed along these roads. The results show that research remains fragmented in approach and usually adopts the point of view of a single road to consumer acceptance of a novel technology. Nevertheless by combining the available evidence recommendation can be made how the different roads contribute to consumer acceptance or rejection of a novel food technology dependent on technology haracteristics. A checklist for the introduction of novel food technologies taking account of all the roads and the technology is presented at the end of this report

    Structure, mineralogy, and microbial diversity of geothermal spring microbialites associated with a deep oil drilling in Romania

    Get PDF
    © 2015 Coman, Chiriac, Robeson, Ionescu, Dragos, Barbu-Tudoran, Andrei, Banciu, Sicora and Podar. Modern mineral deposits play an important role in evolutionary studies by providing clues to the formation of ancient lithified microbial communities. Here we report the presence of microbialite-forming microbial mats in different microenvironments at 32°C, 49°C, and 65°C around the geothermal spring from an abandoned oil drill in Ciocaia, Romania. The mineralogy and the macro- and microstructure of the microbialites were investigated, together with their microbial diversity based on a 16S rRNA gene amplicon sequencing approach. The calcium carbonate is deposited mainly in the form of calcite. At 32°C and 49°C, the microbialites show a laminated structure with visible microbial mat-carbonate crystal interactions. At 65°C, the mineral deposit is clotted, without obvious organic residues. Partial 16S rRNA gene amplicon sequencing showed that the relative abundance of the phylum Archaea was low at 32°C (1%. The dominant bacterial groups at 32°C were Cyanobacteria, Gammaproteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Thermi, Actinobacteria, Planctomycetes, and Defferibacteres. At 49°C, there was a striking dominance of the Gammaproteobacteria, followed by Firmicutes, Bacteroidetes, and Armantimonadetes. The 65°C sample was dominated by Betaproteobacteria, Firmicutes, [OP1], Defferibacteres, Thermi, Thermotogae, [EM3], and Nitrospirae. Several groups from Proteobacteria and Firmicutes, together with Halobacteria and Melainabacteria were described for the first time in calcium carbonate deposits. Overall, the spring from Ciocaia emerges as a valuable site to probe microbes-minerals interrelationships along thermal and geochemical gradients

    Regulation of cellular sterol homeostasis by the oxygen responsive noncoding RNA lincNORS

    Get PDF
    We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O2 in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently found to be implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally occurring genetic variations highly significant for sterol/steroid-related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance
    corecore