4,737 research outputs found

    P27kip1 controls H-Ras/MAPK activation and cell cycle entry via modulation of MT stability

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    The cyclin-dependent kinase (CDK) inhibitor p27(kip1) is a critical regulator of the G1/S-phase transition of the cell cycle and also regulates microtubule (MT) stability. This latter function is exerted by modulating the activity of stathmin, an MT-destabilizing protein, and by direct binding to MTs. We recently demonstrated that increased proliferation in p27(kip1)-null mice is reverted by concomitant deletion of stathmin in p27(kip1)/stathmin double-KO mice, suggesting that a CDK-independent function of p27(kip1) contributes to the control of cell proliferation. Whether the regulation of MT stability by p27(kip1) impinges on signaling pathway activation and contributes to the decision to enter the cell cycle is largely unknown. Here, we report that faster cell cycle entry of p27(kip1)-null cells was impaired by the concomitant deletion of stathmin. Using gene expression profiling coupled with bioinformatic analyses, we show that p27(kip1) and stathmin conjunctly control activation of the MAPK pathway. From a molecular point of view, we observed that p27(kip1), by controlling MT stability, impinges on H-Ras trafficking and ubiquitination levels, eventually restraining its full activation. Our study identifies a regulatory axis controlling the G1/S-phase transition, relying on the regulation of MT stability by p27(kip1) and finely controlling the spatiotemporal activation of the Ras-MAPK signaling pathway

    Common biological phenotypes characterize the acquisition of platinum-resistance in epithelial ovarian cancer cells

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    Standard of care for Epithelial Ovarian Cancer (EOC) patients relies on platinum-based therapy. However, acquired resistance to platinum occurs frequently and predicts poor prognosis. To understand the mechanisms underlying acquired platinum-resistance, we have generated and characterized three platinum-resistant isogenic EOC cell lines. Resistant cells showed 3-to 5- folds increase in platinum IC50. Cross-resistance to other chemotherapeutic agents commonly used in the treatment of EOC patients was variable and dependent on the cell line utilized. Gene expression profiling (GEP) of coding and non-coding RNAs failed to identify a common signature that could collectively explain the mechanism of resistance. However, we observed that all resistant cell lines displayed a decreased level of DNA platination and a faster repair of damaged DNA. Furthermore, all platinum resistant cell lines displayed a change in their morphology and a higher ability to grown on mesothelium. Overall, we have established and characterized three new models of platinum-resistant EOC cell lines that could be exploited to further dissect the molecular mechanisms underlying acquired resistance to platinum. Our work also suggests that GEP studies alone, at least when performed under basal culture condition, do not represent the optimal way to identify molecular alterations linked to DNA repair pathway defects

    Hepatitis B virus-infection related cryoglobulinemic vasculitis. Clinical manifestations and the effect of antiviral therapy: A review of the literature

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    Objective: Hepatitis B virus (HBV) infection causes chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Furthermore, about 20% of the patients develop extrahepatic manifestations such as cryoglobulinemic vasculitis (CV), polyarteritis nodosa, non-rheumatoid arthritis, glomerulonephritis and non-Hodgkin lymphoma. This review analyzed literature data on clinical manifestations of HBV-related CV and the impact of antiviral therapy with analoques nucleotide. Methods: A PubMed search was performed to select eligible studies in the literature, up to July 2022. Results: Some studies have analyzed clinical manifestations in HBV-related CV and have investigated the role of antiviral therapy with nucleotides analogues (NAs). Clinical manifestations of CV vary from mild to moderate (purpura, asthenia and arthralgias) to severe (leg ulcers, peripheral neuropathy, glomerulonephritis, and non-Hodking lymphoma). NAs therapy leads to suppression of HBV-DNA; therefore, it is capable of producing clinical response in the majority of patients with mild to moderate symptoms. Conclusion: Antiviral therapy with NAs is the first choice for HBV suppression and control of mild to moderate disease. In severe vasculitis (glomerulonephritis, progressive peripheral neuropathy and leg ulcers), rituximab alone or with plasma-exchange is always indicated in combination with antiviral therapy

    Estudio del esfuerzo de rodadura en tractores articulados (4WD) y de tracciĂłn delantera asistida (FWA)

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    p.221-229En el autotransporte del tractor se producen tros tipos de pérdidas de transmisión, pérdidas por rodadura y pérdida por patinaje. Las pérdidas por transmisión conciernen al diseño de la misma, las pérdidas por patinaje y rodadura son las que más preocupan al productor (FWA y 4WD) comunes a nuestro mercado agrícola, sobre estas condiciones de suelo diferentes, suelo arado, cama de siembra y siembra directa. Los parámetros evaluados fueron: esfuerzos de rodadura fueron contrastados con las fórmulas de predicción de Wismer y Luth y de MCallister. Las conclusiones obtenidas fueron 1) La potencia pérdida en rodadura se incrementó en suelos de baja capacidad portante; 2) Para predecir esfuerzo de rodadura en tractores (FWA y 4WD) cuando transitan sobre suelos arados se puede utilizar la ecuación de predicción de Wismer y Luth; 3) El porcentaje de potencia del motor pérdida por rodadura fue mayor para el tractor FWA cuando transitó sobre suelos de baja capacidad portante, 4) La menor relación potencia pérdida en rodadura 7 potencia motor fue mejor para el 4 WD en suelo cama de siembra y suelo arado, no así en siembra directa y 5) Se encontró, sobre los suelos blandos, una relación directa entre profundidad de huella y el peso del tractor que lo transitó

    Development and Flight Testing of a Neural Network Based Flight Control System on the NF-15B Aircraft

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    The Intelligent Flight Control System (IFCS) project at the NASA Dryden Flight Research Center, Edwards AFB, CA, has been investigating the use of neural network based adaptive control on a unique NF-15B test aircraft. The IFCS neural network is a software processor that stores measured aircraft response information to dynamically alter flight control gains. In 2006, the neural network was engaged and allowed to learn in real time to dynamically alter the aircraft handling qualities characteristics in the presence of actual aerodynamic failure conditions injected into the aircraft through the flight control system. The use of neural network and similar adaptive technologies in the design of highly fault and damage tolerant flight control systems shows promise in making future aircraft far more survivable than current technology allows. This paper will present the results of the IFCS flight test program conducted at the NASA Dryden Flight Research Center in 2006, with emphasis on challenges encountered and lessons learned

    The INFN-FBK "Phase-2" R&D program

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    We report on the 3-year INFN ATLAS-CMS joint research activity in collaboration with FBK, started in 2014, and aimed at the development of new thin pixel detectors for the High Luminosity LHC Phase-2 upgrades. The program is concerned with both 3D and planar active-edge pixel sensors to be made on 6" p-type wafers. The technology and the design will be optimized and qualified for extreme radiation hardness (2×1016 neq cm-2). Pixel layouts compatible with present (for testing) and future (RD53 65nm) front-end chips of ATLAS and CMS are considered. The paper covers the main aspects of the research program, from the sensor design and fabrication technology, to the results of initial tests performed on the first prototypes. © 2015 Elsevier B.V

    Secado de barras de cereales saladas a base de amaranto cruentus: influencia de la temperatura y el tiempo

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    Se elaboró una barra de cereales salada, nutricionalmente equilibrada a base de semillas de amaranto popeadas (Amaranthus cruentus, variedad Candil), e ingredientes como: avena, salvado extruido, semilla de sésamo, copos de maíz, arroz inflado como fuentes de proteínas y de calcio. Para lograr la cohesión de estos ingredientes se utilizó un ligante no convencional y novedoso que distingue al producto de las barras de consumo masivo. A la formulación seleccionada se le realizó estudios de secado para determinar la influencia de las variables del proceso en la calidad del producto terminado, resultando los mejores atributos cuando las barras se expusieron a 100ºC durante 45 min. Se realizó la evaluación sensorial del producto mediante un panel no entrenado a través de una escala Hedónica resultando con una muy buena aceptación.Centro de Investigación y Desarrollo en Criotecnología de Alimento

    Measurement of ISR-FSR interference in the processes e+ e- --> mu+ mu- gamma and e+ e- --> pi+ pi- gamma

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    Charge asymmetry in processes e+ e- --> mu+ mu- gamma and e+ e- --> pi+ pi- gamma is measured using 232 fb-1 of data collected with the BABAR detector at center-of-mass energies near 10.58 GeV. An observable is introduced and shown to be very robust against detector asymmetries while keeping a large sensitivity to the physical charge asymmetry that results from the interference between initial and final state radiation. The asymmetry is determined as afunction of the invariant mass of the final-state tracks from production threshold to a few GeV/c2. It is compared to the expectation from QED for e+ e- --> mu+ mu- gamma and from theoretical models for e+ e- --> pi+ pi- gamma. A clear interference pattern is observed in e+ e- --> pi+ pi- gamma, particularly in the vicinity of the f_2(1270) resonance. The inferred rate of lowest order FSR production is consistent with the QED expectation for e+ e- --> mu+ mu- gamma, and is negligibly small for e+ e- --> pi+ pi- gamma.Comment: 32 pages,29 figures, to be submitted to Phys. Rev.
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