4,365 research outputs found

    A basic epistemic logic and its algebraic model

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    In this paper we propose an algebraic model for a modal epistemic logic. Although it is known the existence of algebraic models for modal logics, considering that there are so many different modal logics, so it is not usual to give an algebraic model for each such system. The basic epistemic logic used in the paper is bimodal and we can show that the epistemic algebra introduced in the paper is an adequate model for it. In this paper we propose an algebraic model for a modal epistemic logic. Although it is known the existence of algebraic models for modal logics, considering that there are so many different modal logics, so it is not usual to give an algebraic model for each such system. The basic epistemic logic used in the paper is bimodal and we can show that the epistemicalgebra introduced in the paper is an adequate model for it.

    Probing Plasmodium falciparum sexual commitment at the single-cell level

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    Background: Malaria parasites go through major transitions during their complex life cycle, yet the underlying differentiation pathways remain obscure. Here we apply single cell transcriptomics to unravel the program inducing sexual differentiation in Plasmodium falciparum. Parasites have to make this essential life-cycle decision in preparation for human-to-mosquito transmission. Methods: By combining transcriptional profiling with quantitative imaging and genetics, we defined a transcriptional signature in sexually committed cells. Results: We found this transcriptional signature to be distinct from general changes in parasite metabolism that can be observed in response to commitment-inducing conditions. Conclusions: This proof-of-concept study provides a template to capture transcriptional diversity in parasite populations containing complex mixtures of different life-cycle stages and developmental programs, with important implications for our understanding of parasite biology and the ongoing malaria elimination campaign

    Surface Architecture of Histoplasma Capsulatum

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    The dimorphic fungal pathogen Histoplasma capsulatum is the most frequent cause of clinically significant fungal pneumonia in humans. H. capsulatum virulence is achieved, in part, through diverse and dynamic alterations to the fungal cell surface. Surface components associated with H. capsulatum pathogenicity include carbohydrates, lipids, proteins, and melanins. Here, we describe the various structures comprising the cell surface of H. capsulatum that have been associated with virulence and discuss their involvement in the pathobiology of disease

    Hemodynamic evaluation of the right portal vein in healthy dogs of different body weights

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    <p>Abstract</p> <p>Background</p> <p>Doppler ultrasonography is an important tool for evaluating hepatic portal hemodynamics. However, no study in dogs of different body weights, in the range encountered in routine clinical veterinary practice, has been reported. It can be difficult to obtain an ideal insonation angle when evaluating the main portal vein, so evaluation of the right portal vein branch has been described in humans as an alternative. The aim of this study was to analyze, through Doppler ultrasonography, the hemodynamics in the right portal vein branch in dogs of different body weights.</p> <p>Methods</p> <p>Thirty normal dogs were divided in three groups by weight, in order to establish normal values for mean velocity, flow volume and portal congestion index of the right portal vein branch by means of Doppler ultrasonography.</p> <p>Results</p> <p>In all dogs ideal insonation angles were obtained for the right portal vein branch. The average velocity was similar in the three groups, but the portal congestion index and the flow volume differed, showing that the weight of the dog can influence these values.</p> <p>Conclusion</p> <p>Doppler ultrasonography for the evaluation of flow in the right branch of the portal vein could be a viable alternative, or complement, to examining the main vessel segment. This is especially so in those animals in which an ideal insonation angle for examination of the main portal vein is hard to obtain. In addition, the weight of the dog must be considered for the correct evaluation of the portal system hemodynamics, particularly for portal blood flow and the congestion index.</p

    Chromosomal loci important for cotyledon opening under UV-B in Arabidopsis thaliana

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    <p>Abstract</p> <p>Background</p> <p>Understanding of the genetic architecture of plant UV-B responses allows extensive targeted testing of candidate genes or regions, along with combinations of those genes, for placement in metabolic or signal transduction pathways.</p> <p>Results</p> <p>Composite interval mapping and single-marker analysis methods were used to identify significant loci for cotyledon opening under UV-B in four sets of recombinant inbred lines. In addition, loci important for canalization (stability) of cotyledon opening were detected in two mapping populations. One candidate locus contained the gene <it>HY5</it>. Mutant analysis demonstrated that HY5 was required for UV-B-specific cotyledon opening.</p> <p>Conclusions</p> <p>Structured mapping populations provide key information on the degree of complexity in the genetic control of UV-B-induced cotyledon opening in Arabidopsis. The loci identified using quantitative trait analysis methods are useful for follow-up testing of candidate genes.</p

    Preservation of probiotic strains isolated from kefir by spray drying

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    Aims: This work aims to investigate the survival of Lactobacillus kefir CIDCA 8348, Lactobacillus plantarum CIDCA 83114 and Saccharomyces lipolytica CIDCA 812, all isolated from kefir, during spray drying and subsequent storage. Methods and Results: Micro-organisms were grown in De Man, Rogosa, Sharpe (MRS) or yeast medium (YM) medium and harvested in the stationary phase of growth. The thermotolerance in skim milk (D and Z values), the survival of spray drying at different outlet air temperatures and subsequent storage in different conditions during 150 days were studied. The resistance to the heat treatments was higher in Lact. plantarum compared to Lact. kefir and S. lipolytica. The three micro-organisms studied varied considerably in their ability to survive to spray drying processes. Lactobacillus plantarum showed the highest survival rate for all the tested outlet air temperatures and also to the further storage in the dried state. The survival rates of Lact. kefir and S. lipolytica through drying and subsequent storage in the dried state decreased when the drying outlet air temperatures increased. Conclusions: Spray drying is a suitable method to preserve micro-organisms isolated from kefir grains. A high proportion of cells were still viable after 80 days of storage at refrigerated temperatures Significance and Impact of Study: It is the first report about spray-dried probiotic strains isolated from kefir grain and contributes to the knowledge about these micro-organisms for their future application in novel dehydrated products.Fil: Golowczyc, Marina Alejandra. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Silva, J.. Universidad Católica Portuguesa. Escuela Superior de Biotecnología; PortugalFil: Abraham, Analia Graciela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: de Antoni, Graciela Liliana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Teixeira, Paula Mariana. Universidad Católica Portuguesa. Escuela Superior de Biotecnología; Portuga

    Nano-galvanic coupling for enhanced Ag+ release in ZrCN-Ag films: antibacterial application

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    The antibacterial properties of materials developed for medical devices with embedded silver nanoparticles are enhanced by controlling the release of silver ions. In this study, a simple experimental procedure for the augmentation of the silver ion release from ZrCN-Ag coatings is described. The silver nanoparticles are embedded in an amorphous carbon matrix within the ZrCN coatings, to create nano-galvanic couples between the silver and the carbon phases. The galvanic couple promotes the oxidation of silver, and consequently, increases the silver release. It is demonstrated that coatings with a lower silver content, but integrating amorphous carbon phases, can release similar or even a larger amount of Ag+ ions than those with higher Ag content having just ZrCN and Ag phases. The antibacterial tests demonstrate that coatings with silver nanoparticles encapsulated into amorphous phase reveal a larger bacterial zone of inhibition compared to samples with similar or lower silver content. However, it is shown that the antibacterial effect of the coatings not only depends on the ability for silver ion release, but also on the availability of silver nanoparticles on the surface.This research is partially sponsored by FEDER funds through the program COMPETE - Programa Operacional Factores de Competitividade and by Portuguese national funds through FCT-Fundacao para a Ciencia e a Tecnologia, under the projects ANTIMICROBCOAT - PTDC/CTM/102853/2008 and in the framework of the Strategic Projects PEST-C/ FIS/UI607/2011", UID/EMS/00285/2013 and SFRH/BD/80947/2011

    Very high gravity bioethanol revisited: main challenges and advances

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    Over the last decades, the constant growth of the world-wide industry has been leading to more and more concerns with its direct impact on greenhouse gas (GHG) emissions. Resulting from that, rising efforts have been dedicated to a global transition from an oil-based industry to cleaner biotechnological processes. A specific example refers to the production of bioethanol to substitute the traditional transportation fuels. Bioethanol has been produced for decades now, mainly from energy crops, but more recently, also from lignocellulosic materials. Aiming to improve process economics, the fermentation of very high gravity (VHG) mediums has for long received considerable attention. Nowadays, with the growth of multi-waste valorization frameworks, VHG fermentation could be crucial for bioeconomy development. However, numerous obstacles remain. This work initially presents the main aspects of a VHG process, giving then special emphasis to some of the most important factors that traditionally affect the fermentation organism, such as nutrients depletion, osmotic stress, and ethanol toxicity. Afterwards, some factors that could possibly enable critical improvements in the future on VHG technologies are discussed. Special attention was given to the potential of the development of new fermentation organisms, nutritionally complete culture media, but also on alternative process conditions and configurations.This work has been carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)- LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitive ness and Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Pro gramme (Lisboa 2020) and by North Portugal Regional Operational Program (Norte 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and has been supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 and through Project EcoTech (POCI-01-0145- FEDER-032206/ FAPESP 2018/07522-6) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. The authors also acknowledge the financial support of Research Support Foundation of the state of Minas Gerais-FAPEMIG, National Counsel of Technological and Scientific Development-CNPq and Coordination for the Improvement of Higher Education Personnel-CAPES (Finance Code 001).info:eu-repo/semantics/publishedVersio

    Tidal deformability of strange stars and the GW170817 event

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    In this work we consider strange stars formed by quark matter in the color-flavor-locked (CFL) phase of color superconductivity. The CFL phase is described by a Nambu-Jona-Lasinio model with four-fermion vector and diquark interaction channels. The effect of the color superconducting medium on the gluons are incorporated into the model by including the gluon self-energy in the thermodynamic potential. We construct parametrizations of the model by varying the vector coupling GV and comparing the results to the data on tidal deformability from the GW170817 event, the observational data on maximum masses from massive pulsars such as the MSP J0740+6620, and the mass/radius fits to NICER data for PSR J003+0451. Our results point out to windows for the GV parameter space of the model, with and without gluon effects included, that are compatible with all these astrophysical constraints, namely, 0.2
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