1,045 research outputs found

    An Interpretation of the Fan Theorem in Type Theory

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    This article presents a formulation of the fan theorem inMartin-L¨of's type theory. Starting from one of the standard versions of the fan theorem we gradually introduce reformulations leading to a final version which is easy to interpret in type theory. Finally we describe a formal proof of that final version of the fan theorem.Keywords: type theory, fan theorem, inductive bar

    A Certified Extension of the Krivine Machine for a Call-by-Name Higher-Order Imperative Language

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    In this paper we present a compiler that translates programs from an imperative higher-order language into a sequence of instructions for an abstract machine. We consider an extension of the Krivine machine for the call-by-name lambda calculus, which includes strict operators and imperative features. We show that the compiler is correct with respect to the big-step semantics of our language, both for convergent and divergent programs

    Plant derived substances with anti-cancer activity: from folklore to practice

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    Plants have had an essential role in the folklore of ancient cultures. In addition to the use as food and spices, plants have also been utilized as medicines for over 5000 years. It is estimated that 70-95% of the population in developing countries continues to use traditional medicines even today. A new trend, that involved the isolation of plant active compounds begun during the early 19th century. This trend led to the discovery of different active compounds that are derived from plants. In the last decades, more and more new materials derived from plants have been authorized and subscribed as medicines, including those with anti-cancer activity. Cancer is among the leading causes of morbidity and mortality worldwide. The number of new cases is expected to rise by about 70% over the next 2 decades. Thus, there is a real need for new efficient anti-cancer drugs with reduced side effects, and plants are a promising source for such entities. Here we focus on some plant-derived substances exhibiting anti-cancer and chemoprevention activity, their mode of action and bioavailability. These include paclitaxel, curcumin and cannabinoids. In addition, development and use of their synthetic analogs, and those of strigolactones, are discussed. Also discussed are commercial considerations and future prospects for development of plant derived substances with anti-cancer activity

    A certified extension of the Krivine machine for a call-by-name higher-order imperative language

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    In this paper we present a compiler that translates programs from an imperative higher-order language into a sequence of instructions for an abstract machine. We consider an extension of the Krivine machine for the call-by-name lambda calculus, which includes strict operators and imperative features. We show that the compiler is correct with respect to the big-step semantics of our language, both for convergent and divergent programs.http://drops.dagstuhl.de/opus/volltexte/2014/4634publishedVersionFil: Rodríguez, Leonardo Matías. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Fridlender, Daniel Edgardo. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Pagano, Miguel María. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Ciencias de la Computació

    Association between CD14 gene polymorphisms and disease phenotype in sarcoidosis

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    SummaryAlthough the etiology of sarcoidosis is unknown, genetic susceptibility has been demonstrated. Granuloma formation is a key feature in the pathophysiology of sarcoidosis and Crohn’s Disease, raising the possibility that these diseases share common pathogenetic pathways. An association between sarcoidosis and the protein “CD14”, a molecule that is part of the lipopolysaccharide (LPS) cell surface receptor complex, has been suggested.In the current study we evaluated the CD14 gene promoter 159 C→T polymorphic site and soluble CD14 levels in a cohort of 74 sarcoidosis patients compared to 85 healthy controls. We further sought to identify correlations between clinical phenotype, specific genotypes and soluble CD14 levels.We found the TT genotype to be more prevalent in the sarcoidosis patient group than in controls (p=0.03). Serum levels of soluble CD14 were higher in the sarcoidosis patients (p=0.001). Within the patient cohort, CC homozygous patients presented at an older age with milder disease as assessed with the SAC score, longer time to diagnosis, and less impairment of pulmonary function tests.Our study suggests a role of CD14 in the pathogenesis of sarcoidosis, and a clinical phenotype-genotype association. Further mechanistic and epidemiologic studies are needed in order to establish the specific role of CD14 in the etiology, pathogenesis and clinical phenotype of sarcoidosis

    A new antiviral screening method that simultaneously detects viral replication, cell viability, and cell toxicity

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    AbstractViruses cause a variety of illnesses in humans, yet only a few antiviral drugs have been developed; thus, new antiviral drugs are urgently needed. Plants could be a good source of antiviral drugs, they do not have mobility and can only defend themselves by producing compounds against pathogens such as viruses in their own fix environment. These compounds may have the potential to inhibit animal and human viruses as well.In this study, a fast and reliable method for screening plant extracts for specific antiviral activity against Herpes simplex virus type-1 (HSV-1) was developed. This method distinguishes between host cell death due to infectivity and multiplicity of the virus versus toxicity of the plant extract. Extracts from 80 plant and plant organs were screened using this approach. Six plant extracts showed potential to exert specific HSV-1 growth inhibition activity. In two cases, different organs from the same plant showed similar active results. With this method it is possible to screen a large number of extracts in a rapid and accurate way to detect antiviral substances against HSV-I and other viruses

    Decoding Lua: formal semantics for the developer and the semanticist

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    We provide formal semantics for a large subset of the Lua programming language, in its version 5.2. We validate our model by mechanizing it and testing it against the test suite of the reference interpreter of Lua, con rming that our model accurately represents the language. In addition, we set us an ambitious goal: to target both a PL semanticist —not necessarily versed in Lua—, and a Lua developer —not necessarily versed in semantic frameworks. To the former, we present the peculiarities of the language, and how we model them in a traditional small-step operational semantics, embedded within Felleisen-Hieb’s reduction semantics with evaluation contexts. e mechanization is, naturally, performed in PLT Redex, the de facto tool for mechanizing reduction semantics. To the reader unfamiliar with such concepts, we provide, to our best possible within the space limitations, a gentle introduction of the model. It is our hope that developers of the di erent Lua implementations and dialects understand the model and consider it both for testing their work and for experimenting with new language features.Fil: Soldevila Raffa, Mallku Ernesto. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Ziliani, Beta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Silvestre, Bruno. Universidade Federal de Goiás; BrasilFil: Fridlender, Daniel Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Mascarenhas, Fabio. Universidade Federal do Rio de Janeiro; Brasi

    Immune Tolerance to Tumor Antigens Occurs in a Specialized Environment of the Spleen

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    Summary Peripheral tolerance to tumor antigens (Ags) is a major hurdle for antitumor immunity. Draining lymph nodes are considered the privileged sites for Ag presentation to T cells and for the onset of peripheral tolerance. Here, we show that the spleen is fundamentally important for tumor-induced tolerance. Splenectomy restores lymphocyte function and induces tumor regression when coupled with immunotherapy. Splenic CD11b + Gr-1 int Ly6C hi cells, mostly comprising proliferating CCR2 + -inflammatory monocytes with features of myeloid progenitors, expand in the marginal zone of the spleen. Here, they alter the normal tissue cytoarchitecture and closely associate with memory CD8 + T cells, cross-presenting tumor Ags and causing their tolerization. Because of its high proliferative potential, this myeloid cell subset is also susceptible to low-dose chemotherapy, which can be exploited as an adjuvant to passive immunotherapy. CCL2 serum levels in cancer patients are directly related to the accumulation of immature myeloid cells and are predictive for overall survival in patients who develop a multipeptide response to cancer vaccines
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