13 research outputs found

    Temporal Controls of the Asymmetric Cell Division Cycle in Caulobacter crescentus

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    The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA. The regulatory network is cast into a quantitative computational model to investigate in a systematic fashion how these three proteins control the relevant genetic, biochemical and physiological properties of proliferating bacteria. Different controls for both swarmer and stalked cell cycles are represented in the mathematical scheme. The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions. Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella)

    Performance persistence in Spanish equity funds

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    Past literature shows that tests of performance persistence do not agree in the most important mutual fund markets and so there is a need for further research in other smaller countries such as Spain, one of the biggest growth fund markets in Europe in the nineties. Spanish equity funds investing in domestic stocks exhibit mixed results when performance persistence is analysed. These results were obtained from an exhaustive application of parametric and non-parametric procedures proposed in the past financial literature.

    The stiffness of living tissues and its implications for tissue engineering

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    The past 20 years have witnessed ever- growing evidence that the mechanical properties of biological tissues, from nanoscale to macroscale dimensions, are fundamental for cellular behaviour and consequent tissue functionality. This knowledge, combined with previously known biochemical cues, has greatly advanced the field of biomaterial development, tissue engineering and regenerative medicine. It is now established that approaches to engineer biological tissues must integrate and approximate the mechanics, both static and dynamic, of native tissues. Nevertheless, the literature on the mechanical properties of biological tissues differs greatly in methodology, and the available data are widely dispersed. This Review gathers together the most important data on the stiffness of living tissues and discusses the intricacies of tissue stiffness from a materials perspective, highlighting the main challenges associated with engineering lifelike tissues and proposing a unified view of this as yet unreported topic. Emerging advances that might pave the way for the next decadeâ s take on bioengineered tissue stiffness are also presented, and differences and similarities between tissues in health and disease are discussed, along with various techniques for characterizing tissue stiffness at various dimensions from individual cells to organs.The authors would like to acknowledge financial support from the European Research Council, grant agreement ERC-2012-ADG 20120216-321266 (project ComplexiTE). C.F.G. acknowledges scholarship grant no. PD/BD/135253/2017 from Fundação para a Ciência e Tecnologia (FCT). The authors also thank the peer-reviewers for the constructive comments and suggestions that helped to shape this manuscript
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