300 research outputs found

    A review of wildland fire spread modelling, 1990-present, 1: Physical and quasi-physical models

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    In recent years, advances in computational power and spatial data analysis (GIS, remote sensing, etc) have led to an increase in attempts to model the spread and behaviour of wildland fires across the landscape. This series of review papers endeavours to critically and comprehensively review all types of surface fire spread models developed since 1990. This paper reviews models of a physical or quasi-physical nature. These models are based on the fundamental chemistry and/or physics of combustion and fire spread. Other papers in the series review models of an empirical or quasi-empirical nature, and mathematical analogues and simulation models. Many models are extensions or refinements of models developed before 1990. Where this is the case, these models are also discussed but much less comprehensively.Comment: 31 pages + 8 pages references + 2 figures + 5 tables. Submitted to International Journal of Wildland Fir

    Microtubule depolymerization affects endocytosis and exocytosis in the tip and influences endosome movement in tobacco pollen tubes

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    Polarized organization of the cytoplasm of growing pollen tubes is maintained by coordinated function of actin filaments (AFs) and microtubules (MTs). AFs convey post-Golgi secretory vesicles to the tip where some fuse with specific domains of the plasma membrane (PM). Secretory activity is balanced by PM retrieval that maintains cell membrane economy and regulates the polarized composition of the PM, by dividing lipids/proteins between the shank and the tip. Although AFs play a key role in PM internalization in the shank, the role of MTs in exoendocytosis needs to be characterized. The present results show that integrity of the MT cytoskeleton is necessary to control exoendocytosis events in the tip. MT polymerization plays a role in promoting PM invagination in the apex of tobacco pollen tubes since Nocodazole affected PM internalization in the tip and subsequent migration of endocytic vesicles from the apex for degradation. MT depolymerization in the apex and shank was associated with misallocation of a significantly greater amount of internalized PM to the Golgi apparatus and its early recycling to the secretory pathway. FRAP experiments also showed that MT depolymerization in the tip region influenced the rate of exocytosis in the central domain of the apical PM

    Ceriantharia (Cnidaria) of the World: An annotated catalogue and key to species

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    The diversity of Ceriantharia is known from studies formally describing species from the late 18th Century onwards. However, no nomenclators including a list and discussion of all valid species have been produced since a list discussed by Carlgren in 1912. The present nomenclator presents a complete list of adult species of Ceriantharia of the World, including a discussion on each species. It includes the three families (Arachnactidae, Botrucnidiferidae, Cerianthidae) and the currently accepted 54 species based on their adult form. This study serves as a presentation of the “state-of-the-art” list of species of Ceriantharia, and includes a species identification key to support taxonomic identification. Additional in-depth species-byspecies investigations for almost all cerianthid species is still needed, as the information available for most of these species is quite superficial.Fil: Stampar, Sergio. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Reimer, James D.. University of The Ryukyus; JapónFil: Maronna, Maximiliano. Universidade de Sao Paulo; BrasilFil: Lopes, Celine S.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Ceriello, Helen. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Santos, Thais B.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Acuña, Fabian Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Morandini, André C.. Universidade de Sao Paulo; Brasi

    Lupus anticoagulant in patients without thrombotic or obstetric complications

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    El inhibidor lúpico (IL) es un criterio de laboratorio para síndrome antifosfolipídico (SAF); sin embargo, puede detectarse en individuos asintomáticos o estar asociado a otras situaciones clínicas. Presentamos un análisis retrospectivo de 2000 exámenes consecutivos para IL (TTPA, DRVVT), de los cuales 499 casos no presentaban criterios clínicos de SAF (trombosis o complicaciones obstétricas). Aplicando los criterios SSC-ISTH, hallamos IL+ en 27,3% (410/1501) y 43,3% (216/499) de los casos con y sin clínica de SAF respectivamente, analizándose en los casos no-SAF las características clínicas y de laboratorio. Contexto clínico de casos IL+ no-SAF: 18,0% asintomáticos, 34,3% sangrado (epistaxis, gingivorragia, equimosis, hematomas espontáneos) y 47,7% otras manifestaciones (infertilidad, insuficiencia renal crónica, desórdenes autoinmunes, cardiopatía isquémica, trombocitopenia inmune, entre otras). Otras alteraciones de laboratorio en casos IL+ no- SAF, con síntomas de sangrado: alteraciones plaquetarias, descenso de VWF:RCo y/o VWF:Ag, disthrombocytopeminución de FVIII, FII, FV, FVII, FXI o fibrinógeno (sólo o sumado a disminución de plaquetas o FX), inhibidor a-FV o hiperfibrinolisis fueron detectadas en el 55,4% de los casos. El análisis mostró IL+ en un número importante de estudios (216/2000) sin criterios de SAF (1,95% en individuos asintomáticos, 3,70% en pacientes con síntomas de sangrado y 5,15% en casos con otro contexto clínico). Los casos con IL+ y sangrado representan un desafío particular, al requerir evaluar otros posibles defectos subyacentes, que pudiesen justificar el comportamiento clínico. La detección e identificación de defectos combinados requiere de un análisis minucioso, a fin de alcanzar un diagnóstico correcto, esencial para tomar decisiones terapéuticas adecuadas.Despite lupus anticoagulant (LA) is a laboratory criterion for antiphospholipid syndrome (APS), it can be present in asymptomatic subjects or it can be associated with other clinical settings. We present a retrospective analysis of 2000 consecutive LA assays (APTT, DRVVT), 499 of them were performed in patients without APS clinical criteria (thrombosis or obstetric complications). According to SSC-ISTH criteria, LA+ was found in 27.3% (410/1501) and 43.3% (216/499) of cases with or without APS criteria respectively; in no-APS group, the analysis of clinical background and laboratory features was done. Clinical background of LA+ cases no-APS: 18.0% asymptomatic, 34.3% bleeding symptoms (epistaxis, gingivorrhagia, bruising, spontaneous hematomas) and 47.7% other clinical settings (infertility, chronic kidney disease, autoimmune disorders, ischemic heart disease, idiopathic thrombocytopenic purpura, among others). Other abnormal laboratory tests in LA+ cases no- APS with bleeding symptoms: platelet dysfunction; low VWF:RCo and/or VWF:Ag; decrease of FVIII, FII, FV, FVII, FXI or fibrinogen (alone or with low platelet count or low FX), a-FV inhibitor and hyperfibrinolysis were found in the 55.4% of the cases. The analysis showed LA+ in an important number of cases (216/2000) without APS criteria (1.95% in asymptomatic cases, 3.70% in patients with bleeding symptoms and 5.15% in cases with other clinical settings). Those LA+ cases with bleeding symptoms represent a particular challenge because other possible underlying defects have to be analysed in order to explain the clinical behaviour. The detection and identifications of combined defects required a careful analysis in order to achieve an accurate diagnosis, essential for therapeutic decisions.Fil: Remotti, L.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Grosso, S. H.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Ingratti, M. F.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Vera Morandini, Maria Paula. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Woods, Adriana Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bermejo, E. I.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Sánchez Luceros, Analía Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Meschengieser, S. S.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; ArgentinaFil: Lazzari, María Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Blanco, A. N.. Academia Nacional de Medicina de Buenos Aires. Instituto de Investigaciones Hematológicas ; Argentin

    Low drug levels and thrombotic complications in high-risk atrial fibrillation patients treated with direct oral anticoagulants

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    Essentials Direct oral anticoagulants (DOACs) do not require laboratory monitoring currently. DOAC specific measurements were performed at trough in patients with atrial fibrillation. Patients who developed thromboembolic events showed lower DOAC plasma levels. This study supports the concept of measuring DOAC levels at steady state. Summary: Background Direct oral anticoagulants (DOACs) are administered at fixed doses without the need for dose adjustment according to laboratory testing. High interindividual variability in drug blood levels has been shown with all DOACs. To evaluate a possible relationship between DOAC C-trough anticoagulant levels and thromboembolic events, 565 consecutive naive patients with atrial fibrillation (AF) were enrolled in this study performed within the START Laboratory Registry. Methods DOAC-specific measurements (diluted thrombin time or anti-activated factor II calibrated for dabigatran; anti-activated FX calibrated for rivaroxaban or apixaban) at C-trough were performed locally at steady state within 15–25 days after the start of treatment. For each DOAC, the interval of C-trough levels, from the limit of quantification to the highest value, was subdivided into four equal classes, and results were attributed to these classes; the median values of results were also calculated. Thromboembolic complications occurring during 1 year of follow-up were recorded. Results Thromboembolic events (1.8%) occurred in 10 patients who had baseline C-trough levels in the lowest class of drug levels. The incidence of thromboembolic events among patients with DOAC C-trough levels in the lowest level class was 2.4%, and that in the remaining groups was 0%. The patients with thrombotic complications also had a higher mean CHA2DS2-VASc score than that of the total patient population: 5.3 (95% confidence interval [CI] 4.3–6.3 versus 3.0 (95% CI 2.9–3.1). Conclusion In this study cohort, thrombotic complications occurred only in DOAC-treated AF patients who had very low C-trough levels, with a relatively high CHA2DS2-VASc score. Larger studies are warranted to confirm these preliminary observations. © 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis

    Metabolic reprogramming through mitochondrial biogenesis drives adenosine anti-inflammatory effects: new mechanism controlling gingival fibroblast hyper-inflammatory state

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    IntroductionFibroblasts are the dominant stromal cells in the gingival lamina propria with a well-established relevance in regulation of inflammation, and in innate immunity. This is exemplified by their hypersecretion of CXCL8, enhancing leukocyte infiltration in chronic and sustained inflammatory conditions. We have previously shown adenosine to be a key metabolic nucleoside that regulates stromal inflammation, but the underlying mechanisms linking adenosine to the metabolic status of fibroblasts and to the resultant inflammatory response are unclear. This study examined, by seahorse real-time cell metabolic analysis, the bioenergetics of the stromal fibroblast response to extracellular adenosine and IL-1β, focusing on CXCL8 secretion by primary human gingival fibroblasts (HGF).MethodsMarkers of the glycolytic pathway and mitochondrial biogenesis were tracked through immunoblot. Further, the influence of adenosine on mitochondrial accumulation was measured by uptake of MitoTracker Red fluorescent probe and assessment of the role of FCCP (a mitochondrial uncoupler) in CXCL8 secretion and mitochondrial accumulation. ResultsOur results show that the anti-inflammatory response of HGF to extracellular adenosine, typified by reduced CXCL8 secretion, is mediated by mitochondrial oxidative phosphorylation, reflected in higher oxygen consumption rate (OCR). In the presence of IL-1β, adenosine-treated cells induced higher ATP production, basal respiration and proton leak compared to IL-1β without adenosine. Surprisingly, adenosine had no additional effect on the IL-1β-induced higher glycolysis rate demonstrated by the extracellular acidification rate (ECAR). In addition, the higher OCR in adenosine-stimulated cells was not due to the mitochondrial fuel dependency or capacity, but due to an increase in mitochondrial biogenesis and accumulation in the cells with concomitant decrease in mitophagy-required p-PINK1 marker. We detected the accumulation of functional mitochondria with increased activation of the AMPK/SIRT1/PGC-1α pathway. The adenosine-induced uptake of MitoTracker was abrogated by PGC-1α inhibition with SR-12898. In addition, the adenosine effects on reduced CXCL8 were ablated by treatment with FCCP, a potent uncoupler of mitochondrial oxidative phosphorylation.ConclusionOur findings reveal a key role for mitochondrial bioenergetics in regulation of CXCL8-mediated inflammation by HGF through the adenosine/AMPK/SIRT1/PGC-1α axis. Therapeutically targeting this pathway in gingival fibroblasts might be a promising future strategy to modulate stromal-mediated sustained hyper-inflammatory responses

    A wildland fire model with data assimilation

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    A wildfire model is formulated based on balance equations for energy and fuel, where the fuel loss due to combustion corresponds to the fuel reaction rate. The resulting coupled partial differential equations have coefficients that can be approximated from prior measurements of wildfires. An ensemble Kalman filter technique with regularization is then used to assimilate temperatures measured at selected points into running wildfire simulations. The assimilation technique is able to modify the simulations to track the measurements correctly even if the simulations were started with an erroneous ignition location that is quite far away from the correct one.Comment: 35 pages, 12 figures; minor revision January 2008. Original version available from http://www-math.cudenver.edu/ccm/report
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