275 research outputs found

    Seismic performance of historical buildings based on discrete element method: an adobe church

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    This article presents the main concepts and the application of the discrete element method (DEM) for evaluating the seismic performance of historical buildings. Furthermore, the out-of-plane behavior of an adobe church with thick walls, in which the morphology of the cross-section can have an influence on the response, was evaluated by the DEM. The performance of rigid and deformable blocks models was compared, and the sensitivity of the numerical model to the variation of critical parameters was investigated. The results allowed the identification of the most vulnerable elements and a proposal of recommendations for reducing the seismic vulnerability

    Engineering simulations of a super-complex cultural heritage building: Ica Cathedral in Peru

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    The Cathedral of Ica, Peru, is one of the four prototype buildings involved in the ongoing Seismic Retrofitting Project, initiative of the Getty Conservation Institute. The complex historical building, which was heavily damaged by earthquakes in 2007 and 2009, can be divided into two substructures: an external masonry envelope and an internal timber frame built by a construction method known as quincha technique. This study makes use of the information available in literature and the results obtained from experimental campaigns performed by Pontificia Universidad Catlica del PerA and University of Minho. Nonlinear behaviour of masonry is simulated in the numerical models by considering specified compressive and tensile softening behaviour, while isotropic homogeneous and linear behaviour is adopted for modelling timber with appropriate assumptions on the connections. A single representative bay was initially studied by performing linear elastic analysis and verifying the compliance with the various criteria specified by the applicable normative to discuss the actual failure of Ica Cathedral. Afterwards, the structural behaviour of the two substructures composing the Cathedral is evaluated independently. Finally, the interaction of these two substructures is investigated by performing structural analysis on the entire structure of Ica Cathedral. Several structural analysis techniques, including eigenvalue, nonlinear static and dynamic analyses, are performed in order to: (1) evaluate the dominant mode shapes of the structure; (2) validate the numerical models by reproducing the structural damage observed in situ; (3) estimate the structural performance; and (4) identify the main failure mechanisms.This work was carried out with funding from the Getty Seismic Retrofitting Project under the auspices of the Getty Conservation Institute (GCI). This work is also partially financed by FEDER funds through the Competitivity Factors Operational Programme-COMPETE and by national funds through FCT-Foundation for Science and Technology within the scope of the projects POCI-01-0145-FEDER-007633 and PTDC/ECM-EST/2777/2014.info:eu-repo/semantics/publishedVersio

    In vitro-generated Tc17 cells present a memory phenotype and serve as a reservoir of Tc1 cells in vivo

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    Indexación: Scopus.Memory CD8+ T cells are ideal candidates for cancer immunotherapy because they can mediate long-term protection against tumors. However, the therapeutic potential of different in vitro-generated CD8+ T cell effector subsets to persist and become memory cells has not been fully characterized. Type 1 CD8+ T (Tc1) cells produce interferon-γ and are endowed with high cytotoxic capacity, whereas IL-17-producing CD8+ T (Tc17) cells are less cytotoxic but display enhanced self-renewal capacity. We sought to evaluate the functional properties of in vitro-generated Tc17 cells and elucidate their potential to become long lasting memory cells. Our results show that in vitro-generated Tc17 cells display a greater in vivo persistence and expansion in response to secondary antigen stimulation compared to Tc1 cells. When transferred into recipient mice, Tc17 cells persist in secondary lymphoid organs, present a recirculation behavior consistent with central memory T cells, and can shift to a Tc1 phenotype. Accordingly, Tc17 cells are endowed with a higher mitochondrial spare respiratory capacity than Tc1 cells and express higher levels of memory-related molecules than Tc1 cells. Together, these results demonstrate that in vitro-generated Tc17 cells acquire a central memory program and provide a lasting reservoir of Tc1 cells in vivo, thus supporting the use of Tc17 lymphocytes in the design of novel and more effective therapies.https://www.frontiersin.org/articles/10.3389/fimmu.2018.00209/ful

    SARS-CoV-2 outbreak on a Spanish mink farm: epidemiological, molecular, and pathological studies

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    Farmed minks have been reported to be highly susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and may represent a risk to humans. In this study, we describe the first outbreak of SARS-CoV-2 occurred on a mink farm in Spain, between June and July 2020, involving 92,700 animals. The outbreak started shortly after some farm workers became seropositive for SARS-CoV-2. Minks showed no clinical signs compatible with SARS-CoV-2 infection throughout the outbreak. Samples from 98 minks were collected for histopathological, serological, and molecular studies. Twenty out of 98 (20.4%) minks were positive by RT-qPCR and 82 out 92 (89%) seroconverted. This finding may reflect a rapid spread of the virus at the farm with most of the animals overcoming the infection. Additionally, SARS-CoV-2 was detected by RT-qPCR in 30% of brain samples from positive minks. Sequencing analysis showed that the mink sequences were not closely related with the other mink SARS-CoV-2 sequences available, and that this mink outbreak has its probable origin in one of the genetic variants that were prevalent in Spain during the first COVID-19 epidemic wave. Histological studies revealed bronchointerstitial pneumonia in some animals. Immunostaining of viral nucleocapsid was also observed in nasal turbinate tissue. Farmed minks could therefore constitute an important SARS-CoV-2 reservoir, contributing to virus spread among minks and humans. Consequently, continuous surveillance of mink farms is needed

    Análisis de crecimiento del pasto Cuba OM-22 (Pennisetum purpureum x Pennisetum glaucum) en el trópico seco

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    Objective: To analyze a growth curve of the Cuba OM-22 grass (Pennisetum purpureum x Pennisetum glaucum), to find the optimum harvest time, in the dry tropics. Design/methodology/approach: The variables were total yield and by leaf and stem component, height of the plant, intercepted radiation, growth rate, weight per stem, leaf: stem ratio and stem population. They were evaluated at 20 day intervals, over a period of 110 days, with the exception of the first sample that was at 30 days. The data were analyzed using the SAS GLM procedure, under an experimental randomized block design, with measures repeated over time, with three repetitions. Results: The maximum production of total yield and growth rate was reached at 110 days after cutting with 38,600 kg DM ha-1 and 435 kg DM ha-1 d-1, respectively. Limitations on study/implications: After 70 days, a greater biomass accumulation of biomass is reported, but with a lower quality of structural characteristics.  Findings/conclusions: The optimal cutting moment of the Cuba OM-22 grass is when it has higher leaf yield in this growth analysis was at 70 days after cutting, reporting a height of 132 cm and intercepted radiation of 95%.Objetivo: El objetivo de este ensayo fue analizar una curva de crecimiento del pasto Cuba OM-22 (Pennisetum purpureum x Pennisetum glaucum), para encontrar el momento óptimo de cosecha, en el trópico seco. Diseño/Metodología/Aproximación: Las variables fueron rendimiento total y por componente hoja y tallo, altura de la planta, radiación interceptada, tasa de crecimiento, peso por tallo, relación hoja:tallo y población de tallos. Se evaluaron a intervalos de 20 días, en un periodo de 110 días, a excepción del primer muestreo que fue a los 30 días. Los datos se analizaron mediante el procedimiento GLM de SAS, bajo un diseño experimental de bloques al azar, con medidas repetidas en el tiempo, con tres repeticiones. Resultados: La máxima producción de rendimiento total y tasa de crecimiento se alcanzó a los 110 días después del corte con 38,600 kg MS ha-1 y 435 kg MS ha-1 d-1, respectivamente. Limitaciones del estudio/implicaciones: Después de los 70 días se reporta mayor acumulación de biomasa, pero con menor calidad de características estructurales.  Hallazgos/conclusiones: El momento óptimo del corte del pasto Cuba OM-22 es cuando tiene mayor rendimiento de hoja en este análisis de crecimiento fue a los 70 días después del corte reportando una altura de 132 cm y radiación interceptada de 95%

    Land conflict in peri-urban areas: Exploring the effects of land reform on informal settlement in Mexico

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    Peri-urban areas are often subject to intensive construction, through both formal and informal processes. As land transitions from rural to urban status, different land tenure and administration systems may come into conflict, leading to disputes, contestation and, in some cases, violence. However, little is known about the precise causes of peri-urban land conflict. In Mexico, peri-urban growth has historically proceeded peacefully, owing to the control exerted by a corporatist system of government, and the political use of land tenure regularisation. However, the effects of land reforms on transactions at the peri-urban fringe, in the context of wider processes of liberalisation, may be increasing vulnerability to conflict over land. This paper explores these issues through a case study of an irregular settlement on the peri-urban fringe of the provincial Mexican city of Xalapa, where contestations over informally developed land have escalated into violent encounters between groups of settlers and the state. The findings show that vulnerability to conflict in peri-urban areas can be attributed to the interaction of macro-level processes with local-level factors, including diverse claims, overlapping legal and governance frameworks and, critically, local power relations

    The T cell differentiation landscape is shaped by tumour mutations in lung cancer

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    Tumour mutational burden (TMB) predicts immunotherapy outcome in non-small cell lung cancer (NSCLC), consistent with immune recognition of tumour neoantigens. However, persistent antigen exposure is detrimental for T cell function. How TMB affects CD4 and CD8 T cell differentiation in untreated tumours and whether this affects patient outcomes is unknown. Here, we paired high-dimensional flow cytometry, exome, single-cell and bulk RNA sequencing from patients with resected, untreated NSCLC to examine these relationships. TMB was associated with compartment-wide T cell differentiation skewing, characterized by loss of TCF7-expressing progenitor-like CD4 T cells, and an increased abundance of dysfunctional CD8 and CD4 T cell subsets with strong phenotypic and transcriptional similarity to neoantigen-reactive CD8 T cells. A gene signature of redistribution from progenitor-like to dysfunctional states was associated with poor survival in lung and other cancer cohorts. Single-cell characterization of these populations informs potential strategies for therapeutic manipulation in NSCLC
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