105 research outputs found

    Efeitos de fungos termófilos sobre a madeira de Eucalyptus saligna: III. a população fúngica.

    Get PDF
    Este é um trabalho complementar a uma série de estudos com fungos termófilos, em madeira de eucalipto. Seu objetivo foi determinar a ação de uma população de fungos termófilos sobre a madeira e a celulose, obtida com cavacos de madeira de Eucalyptus saligna. Amostras de cavacos secos ao ar foram esterilizados por autoclavagem. Após a inoculação, os cavacos foram incubados, por 30 dias, a 30, 40 e 50oC. O inóculo foi preparado com uma amostra de 20 g de cavacos naturalmente contaminados com os fungos: Aspergillus sp., Dactylomyces thermophilus, Penicillium bacillisporum, Rhizomucor sp., Sporotrichum sp. e Thermoascus aurantiacus. Os cavacos foram analisados quanto aos teores de holocelulose, lignina e extrativos. Preparou-se, também, celulose não branqueada com os cavacos dos tratamentos e analisou-se o rendimento bruto da celulose. A análise dos resultados mostrou que os teores de holocelulose e lignina permaneceram inalterados revelando que os fungos não degradam celulose ou lignina. A diminuição nos teores de extrativos começaram a ser detectados a 40 e 50oC, exceção feita aos açúcares livres em etanol. O maior decréscimo ocorreu a 50oC. O decréscimo no teor foi observado na fração solúvel em etanol-tolueno (19,3%), em diclorometano (7,1%) e em água quente (4%); com extrativos totais e açúcares livres em etanol, o decréscimo foi de 8,6% e 4,8%, respectivamente. A análise da produção de celulose não branqueada verificou-se uma relação direta entre produção e a temperatura de incubação. Cavacos não inoculados e os inoculados/incubados a 30oC produziram 50,8% de celulose, enquanto que os incubados a 40 e 50oC produziram 52 e 53,1%, respectivamente

    Electronics design of the RPC system for the OPERA muon spectrometer

    Get PDF
    The present document describes the front-end electronics of the RPC system that instruments the magnet muon spectrometer of the OPERA experiment. The main task of the OPERA spectrometer is to provide particle tracking information for muon identification and simplify the matching between the Precision Trackers. As no trigger has been foreseen for the experiment, the spectrometer electronics must be self-triggered with single-plane readout capability. Moreover, precision time information must be added within each event frame for off-line reconstruction. The read-out electronics is made of three different stages: the Front-End Boards (FEBs) system, the Controller Boards (CBs) system and the Trigger Boards(TBs) system. The FEB system provides discrimination of the strip incoming signals; a FAST-OR output of the input signals is also available for trigger plane signal generation. FEB signals are acquired by the CB system that provides the zero suppression and manages the communication to the DAQ and Slow Control. A Trigger Board allows to operate in both self-trigger mode (the FEB’s FAST-OR signal starts the plane acquisition) or in external-trigger mode (different conditions can be set on the FAST-OR signals generated from different planes)

    A study of backward going pp and π\pi^{-} in νμCC\nu_{\mu}CC interactions with the NOMAD detector

    Get PDF
    Backward proton and π\pi^- production has been studied in νμCC\nu_{\mu}CC interactions with carbon nuclei. Detailed analyses of the momentum distributions, of the production rates, and of the general features of events with a backward going particle, have been carried out in order to understand the mechanism producing these particles. The backward proton data have been compared with the predictions of the reinteraction and the short range correlation models.Comment: 29 pages, 14 figures, submitted to Nucl. Phys.

    A mouse model reproducing the pathophysiology of neonatal group B streptococcal infection

    Get PDF
    Group B streptococcal (GBS) meningitis remains a devastating disease. The absence of an animal model reproducing the natural infectious process has limited our understanding of the disease and, consequently, delayed the development of effective treatments. We describe here a mouse model in which bacteria are transmitted to the offspring from vaginally colonised pregnant females, the natural route of infection. We show that GBS strain BM110, belonging to the CC17 clonal complex, is more virulent in this vertical transmission model than the isogenic mutant BM110∆cylE, which is deprived of hemolysin/cytolysin. Pups exposed to the more virulent strain exhibit higher mortality rates and lung inflammation than those exposed to the attenuated strain. Moreover, pups that survive to BM110 infection present neurological developmental disability, revealed by impaired learning performance and memory in adulthood. The use of this new mouse model, that reproduces key steps of GBS infection in newborns, will promote a better understanding of the physiopathology of GBS-induced meningitis.The authors gratefully acknowledge the help of Encarnaca̧ ̃o Ribeiro for excellent technical assistance, Joana Tavares for assisting with IVIS Lumina LT, Susana Roque for the luminex instrument experiments, the Molecular Microbiology group at i3S for microscope use, and the Portuguese architect and artist Gil Ferreira da Silva for the artworks included in the last figure. This work was supported by funds from Foundation for Science and Technology (FCT), European Regional Development Fund (FEDER) and Compete under project POCI-01-0145-FEDER-016607 (PTDC/IMI-MIC/1049/2014) and from the project NORTE-01-0145-FEDER-000012, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). T.S. and A.M. were supported by Investigador FCT (IF/00875/2012 and IF/00753/2014), POPH and Fundo Social Europeu. E.B.A. and C.C.P. hold postdoctoral fellowships from FCT (PTDC/IMI-MIC/1049/2014 and SFRH/BPD/91962/2012). Ar.F. and P.T.C. were supported by Laboratoire d’Excellence (LABEX) Integrative Biology of Emerging Infectious Diseases (grant ANR-10-LABX-62-IBEID).info:eu-repo/semantics/publishedVersio

    The Neurotrophic Receptor Ntrk2 Directs Lymphoid Tissue Neovascularization during Leishmania donovani Infection

    Get PDF
    The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80hiCD11bloCD11c+ macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis

    Design of bio-nanosystems for oral delivery of functional compounds

    Get PDF
    Nanotechnology has been referred to as one of the most interesting topics in food technology due to the potentialities of its use by food industry. This calls for studying the behavior of nanosystems as carriers of biological and functional compounds aiming at their utilization for delivery, controlled release and protection of such compounds during food processing and oral ingestion. This review highlights the principles of design and production of bio-nanosystems for oral delivery and their behavior within the human gastrointestinal (GI) tract, while providing an insight into the application of reverse engineering approach to the design of those bio-nanosystems. Nanocapsules, nanohydrogels, lipid-based and multilayer nanosystems are discussed (in terms of their main ingredients, production techniques, predominant forces and properties) and some examples of possible food applications are given. Phenomena occurring in in vitro digestion models are presented, mainly using examples related to the utilization of lipid-based nanosystems and their physicochemical behavior throughout the GI tract. Furthermore, it is shown how a reverse engineering approach, through two main steps, can be used to design bio-nanosystems for food applications, and finally a last section is presented to discuss future trends and consumer perception on food nanotechnology.Miguel A. Cerqueira, Ana C. Pinheiro, Helder D. Silva, Philippe E. Ramos, Ana I. Bourbon, Oscar L. Ramos (SFRH/BPD/72753/2010, SFRH/BD/48120/2008, SFRH/BD/81288/2011, SFRH/BD/80800/2011, SFRH/BD/73178/2010 and SFRH/BPD/80766/2011, respectively) are the recipients of a fellowship from the Fundacao para a Ciencia e Tecnologia (FCT, POPH-QREN and FSE Portugal). Maria L. Flores-Lopez thanks Mexican Science and Technology Council (CONACYT, Mexico) for PhD fellowship support (CONACYT Grant number: 215499/310847). The support of EU Cost Actions FA0904 and FA1001 is gratefully acknowledged

    Host–pathogen interactions in bacterial meningitis

    Get PDF
    corecore