87 research outputs found

    External Control in Process Algebra for Systems Biology

    Get PDF
    A critical aspect in the modeling of biological systems is the description view point. On the one hand, the Stochastic \u3c0-calculus formalism provides an intuitive and compact representation from an internal perspective. On the other hand, other proposed languages such as Hybrid Automata and Stochastic Concurrent Constraint Programming introduce in the system description an external control and provide more structured models. This work aims at bridging the above discussed gap. In particular, we propose a different approach for the encoding of biological systems in Stochastic \u3c0-calculus in the direction of introducing an external control and comparing different formalisms. We show the effectiveness of our method on some examples

    A Semantic Hierarchy for Erasure Policies

    Get PDF
    We consider the problem of logical data erasure, contrasting with physical erasure in the same way that end-to-end information flow control contrasts with access control. We present a semantic hierarchy for erasure policies, using a possibilistic knowledge-based semantics to define policy satisfaction such that there is an intuitively clear upper bound on what information an erasure policy permits to be retained. Our hierarchy allows a rich class of erasure policies to be expressed, taking account of the power of the attacker, how much information may be retained, and under what conditions it may be retained. While our main aim is to specify erasure policies, the semantic framework allows quite general information-flow policies to be formulated for a variety of semantic notions of secrecy.Comment: 18 pages, ICISS 201

    Requirements for Membrane Attack Complex Formation and Anaphylatoxins Binding to Collagen-Activated Platelets

    Get PDF
    The activation of complement during platelet activation is incompletely understood.We sought to explore the formation of C5b-9 and anaphylatoxins binding to collagen-activated platelets.C5b-9, anaphylatoxins C3a, C4a and C5a, and anaphylatoxin receptors C3aR1 and C5aR were measured by flow cytometry and/or confocal microscopy. Platelet microparticles were quantified by flow cytometry, and their C5b-9 content was determined by western blot analyses. In all experiments, sodium citrate was used for blood anticoagulation.C5b-9 rapidly formed on the platelet surface following activation with collagen, TRAP, ADP or A23187, but was surprisingly restricted to a subset of platelets (1 to 15%) independently of P-selectin or phosphatidylserine exposure. Following collagen activation, C5b-9-positive platelets in thrombi were found associated with collagen fibres. C5b-9 formation was obliterated by Mg(2+)-EGTA and significantly reduced by the thrombin inhibitor hirudin (-37%, p<0.05), but was unaffected by chondroitinase, compstatin, SCH79797 (PAR-1 inhibitor), or in the PRP of a MBL-deficient donor. Compstatin and Mg(2+)-EGTA, but not hirudin, SCH79797 or chondroitinase, inhibited the formation of collagen-induced microparticles (-71% and -44%, respectively, p<0.04). These microparticles contained greater amounts of C5b-9 compared with the other agonists. Platelet activation by collagen or convulxin resulted in the strong binding of anaphylatoxins and the exposure of receptors C3aR1 and C5aR (CD88) on their surface.C5b-9 formation on collagen-activated platelets is i) partially controlled by thrombin, ii) restricted to a subset of platelets, and iii) can occur without P-selectin expression or phosphatidylserine exposure. Activated platelets bind anaphylatoxins on their surface and express C3a and C5a receptors, which may contribute to the localization of inflammatory processes during thrombosis

    Chemical properties and protective effect of Rosmarinus officinalis: mitigation of lipid peroxidation and DNA-damage from arsenic exposure

    Get PDF
    Recent studies have implicated dietary factors in the cause and prevention of important diseases, with strong evidence that plant’s compounds can protect against these diseases. Moreover, food security and environmental contamination are topics in focus at the moment. In this view, contamination by arsenic (As) has received much attention as well as some spices with medicinal properties. Among these plants, the use of Rosmarinus officinalis L. has demonstrated antioxidant properties besides being used for circulatory disorders. Therefore, we measured the mitotic index of Allium cepa L. and characterized the antioxidant effects to determine the capacity of R. officinalis to ameliorate arsenic-induced DNA damage. R. officinalis extract showed no mutagenic effects and exhibited antimutagenic potential, reducing the DNA damage, anaphase-telophase briges and micronuclei chromosome aberrations that result from treatment with the arsenic. Additionally, reduction in arsenic- induced lipid peroxidation was also observed

    A regulated deficit irrigation strategy for hedgerow olive orchards with high plant density

    Get PDF
    Background & Aims There is not a consensus on the best irrigation approach for super-high density (SHD) olive orchards. Our aim was to design and test a regulated deficit irrigation (RDI) strategy for a sustainable balance between water saving, tree vigour and oil production. Methods We tested our RDI strategy for 3 years in an ‘Arbequina’ orchard with 1,667 trees ha−1. Two levels of irrigation reduction were applied, 60RDI and 30RDI, scaled to replacing 60 % and 30 %, respectively, of the of irrigation needs (IN). We also had a full irrigation (FI) treatment as control, with IN totalling 4,701 m3 ha−1 Results The 30RDI treatment showed the best balance between water saving, tree vigour and oil production. With a yearly irrigation amount (IA) of 1,366 m3 ha−1, which meant 72 % water saving as compared to FI, the reduction in oil yield was 26 % only. Conclusions Our results, together with recent knowledge on the effect of water stress on fruit development, allowed us to suggest a potentially improved RDI strategy for which a total IA of ca. 2,100 m3 ha−1 was calculated. Both some management details and the benefits of this suggested RDI strategy are still to be tested

    The Arabidopsis thaliana F-Box Protein FBL17 Is Essential for Progression through the Second Mitosis during Pollen Development

    Get PDF
    In fungi and metazoans, the SCF-type Ubiquitin protein ligases (E3s) play a critical role in cell cycle regulation by degrading negative regulators, such as cell cycle-dependent kinase inhibitors (CKIs) at the G1-to-S-phase checkpoint. Here we report that FBL17, an Arabidopsis thaliana F-box protein, is involved in cell cycle regulation during male gametogenesis. FBL17 expression is strongly enhanced in plants co-expressing E2Fa and DPa, transcription factors that promote S-phase entry. FBL17 loss-of-function mutants fail to undergo pollen mitosis II, which generates the two sperm cells in mature A. thaliana pollen. Nonetheless, the single sperm cell-like cell in fbl17 mutants is functional but will exclusively fertilize the egg cell of the female gametophyte, giving rise to an embryo that will later abort, most likely due to the lack of functional endosperm. Seed abortion can, however, be overcome by mutations in FIE, a component of the Polycomb group complex, overall resembling loss-of-function mutations in the A. thaliana cyclin-dependent kinase CDKA;1. Finally we identified ASK11, as an SKP1-like partner protein of FBL17 and discuss a possible mechanism how SCFFBL17 may regulate cell division during male gametogenesis

    Informe de economía e instituciones

    No full text
    Resumen ejecutivo: En la primera columna, Por qué y cómo “cerrar” la grieta económica, el autor profundiza en la cuestión de la polarización, y el impacto que esta genera en el desarrollo económico de la Argentina. Señala el carácter histórico que desempeña dicho concepto a nivel macroeconómico, conectado con el conflicto de intereses entre dos grandes sectores de la economía. Luego señala que el resultado de querer imponer un modelo por sobre otro, sin una coherencia a largo plazo, ha provocado un costo social y humano muy alto. Es por ello que, finalmente, resalta la importancia de consensos que desarticulen la polarización. En la segunda columna, Desarrollo financiero y marco institucional, el autor analiza la importancia de un sistema financiero fuerte para el desarrollo económico. Posteriormente enfatiza las condiciones necesarias para un desarrollo financiero sostenido, remarcando lo fundamental que resulta un marco institucional que permita el cumplimiento de los contratos, con leyes que regulen los derechos de los inversores. Finalmente, señala el caso de Argentina, donde persiste una macroeconomía inestable y un marco institucional débil frente al cumplimiento de contratos. De esta manera, el desarrollo financiero para el crecimiento económico de manera sostenible resulta complejo. En la tercera columna, Brasil: Deterioro por todos lados la autora pasa a revista a un conjunto de falencias en la política económica, que provocaron una de las peores recesiones de su historia. Señala, que dicha recesión ha generado un deterioro en la imagen de los correspondientes gobiernos de turno. Además, explica que Brasil no ha podido combinar la estabilidad macroeconomía con bajos niveles de crecimiento. En relación a lo anterior, hace referencia a un conjunto de medidas tomadas para aumentar el crecimiento, las cuales no pudieron aumentar la demanda interna, y consecuentemente se perdió la estabilidad macroeconómica.Contenidos: Resumen ejecutivo -- Por qué y cómo “cerrar” la grieta económica / Marcelo F. Resico -- Desarrollo financiero y marco institucional / Pablo Souto -- Brasil: deterioro por todos lados / Maria Antonieta Del Tedesco Lin

    Cognitive disorders in migrants: retrospective analysis in a Center for Cognitive Disorders and Dementia in Milan

    No full text
    Background: The number of migrants with dementia in Italy might increase considerably over the coming years due to the increasing flow of immigration and the aging of the population. Aims: We retrospectively registered rate and characteristics of demented migrant outpatients referred to one hospital in Milan from 2001 to 2017. Methods: Information about country of origin of migrants attending general neurology and memory clinics was obtained from their Italian tax code. Socio-demographic, cultural, and clinical characteristics were derived from their medical records. Results: Migrants with cognitive decline represented a minimal fraction (3.1%) of demented outpatients, but a grow rate of 400% was registered within the period of observation. A linguistic barrier resulted as the main obstacle for the application of available diagnostic tools for dementia. Discussion/conclusion: Given the above-reported data, the implementation of strategies (such as transcultural diagnostic instruments) and policies dedicated to this growing health problem appears a priority for our health systems
    corecore