169 research outputs found

    Explorando Temas en Recursos Educativos Abiertos de Tecnologías de la Información a través del Algoritmo LDA

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    This paper explores the application of machine learning and text mining techniques to discover OER issues in the context of Engineering Education. Applying the LDA (Latent Dirichlet Allocation) algorithm, themes are extracted from OER, it is possible to consider them as additional metadata. This augmentation serves to enhance the description and categorization of OER. Furthermore, this study introduces a methodology to automatically identify topics in open educational resources. In this research, a dataset of 80 OER was obtained from the Skills Commons repository. The highest coherence value achieved at 0.42, emerged when the number of topics was 9 in the LDA model. These nine topics are closely associated with Information Technology Education.Este artículo aplica el algoritmo Latent Dirichlet Allocation, LDA, como una técnica de aprendizaje de máquina y minería de texto para descubrir temas en OER en el contexto de la educación en ingeniería. El algoritmo LDA permite extraer temas, en este estudio los temas que se extraen de OER pueden ser considerados como metadatos adicionales que enriquecerán la descripción y clasificación de los mismos. Además, se define una metodología para la identificación automática de temas en los recursos educativos abiertos. En esta investigación, se utiliza un dataset de 80 OER extraído del repositorio Skills Commons. El valor más alto de coherencia es 0.42, cuando el número de temas en el modelo LDA es 9. Estos nueve temas están relacionados con Educación en Tecnologías de la Información

    Differential permissivity of human cerebrovascular endothelial cells to enterovirus infection and specificities of enterovirus 71 in crossing an in vitro model of human blood brain barrier

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    Human cerebral microvascular endothelial cells (hCMEC/D3 cell line) form a steady polarized barrier when cultured in vitro on a permeable membrane. Their susceptibility to enterovirus (EV) strains was analysed to investigate how these viruses may cross the blood-brain barrier. A sample of 88 virus strains was selected on phylogenetic features among 44 epidemiologically relevant types of the four EV species A-D. The EV-A71 genome was replicated at substantial rates while the infectious virus was released at extremely low but sustained rates at both barrier sides for at least 4 days. EV-A71 antigens were detected in a limited number of cells. The properties of the endothelial barrier (structure and permeability) remained intact throughout infection. The chronic EV-A71 infection was in sharp contrast with the productive infection of cytolytic EVs (e.g. echoviruses 6 and 30). The hCMEC/D3 barriers infected with the latter EVs exhibited elevated proportions of apoptotic and necrotic cells, which resulted in major injuries to the endothelial barriers with dramatic increase of paracellular permeability and virus crossing to the abluminal side. The following intracellular rearrangements were also seen: early destruction of the actin cytoskeleton, remodelling of intracellular membranes, and reorganization of the mitochondrion network in a small cluster near the perinuclear space

    Development of nine microsatellite loci for <i>Trypanosoma lewisi</i>, a potential human pathogen in Western Africa and South-East Asia, and preliminary population genetics analyses

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    This manuscript (word file), presents results obtained while developing microsatellite markers for the parasite T. lewisi and the first population genetics data analysis for this species. This parasite is found mainly in rodents (rats) and is transmitted by fleas. To this respect, it shares the same cycle as other human pathogens (plague, murine typhus) The first results suggest that the subpopulation unit for these parasite populations may be found at very small scales, neighborhoods of cities, and probably even at lower scales (e.g. homes). Data also suggest an operational life cycle (generation time) of 1-2 months, as for other trypanosome species. The excel file contains all raw data. These results, even if they need being refined, but already shed some light on the ecology of this host-parasite-vector system, together with the ecology of other pathogenic agents sharing the same cycle

    Lactate dehydrogenases promote glioblastoma growth and invasion via a metabolic symbiosis

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    Lactate is a central metabolite in brain physiology but also contributes to tumor development. Glioblastoma (GB) is the most common and malignant primary brain tumor in adults, recognized by angiogenic and invasive growth, in addition to its altered metabolism. We show herein that lactate fuels GB anaplerosis by replenishing the tricarboxylic acid (TCA) cycle in absence of glucose. Lactate dehydrogenases (LDHA and LDHB), which we found spatially expressed in GB tissues, catalyze the interconversion of pyruvate and lactate. However, ablation of both LDH isoforms, but not only one, led to a reduction in tumor growth and an increase in mouse survival. Comparative transcriptomics and metabolomics revealed metabolic rewiring involving high oxidative phosphorylation (OXPHOS) in the LDHA/B KO group which sensitized tumors to cranial irradiation, thus improving mouse survival. When mice were treated with the antiepileptic drug stiripentol, which targets LDH activity, tumor growth decreased. Our findings unveil the complex metabolic network in which both LDHA and LDHB are integrated and show that the combined inhibition of LDHA and LDHB strongly sensitizes GB to therapy.publishedVersio

    Hypoxia and the Hypoxic Response Pathway Protect against Pore-Forming Toxins in C. elegans

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    Pore-forming toxins (PFTs) are by far the most abundant bacterial protein toxins and are important for the virulence of many important pathogens. As such, cellular responses to PFTs critically modulate host-pathogen interactions. Although many cellular responses to PFTs have been recorded, little is understood about their relevance to pathological or defensive outcomes. To shed light on this important question, we have turned to the only genetic system for studying PFT-host interactions—Caenorhabditis elegans intoxication by Crystal (Cry) protein PFTs. We mutagenized and screened for C. elegans mutants resistant to a Cry PFT and recovered one mutant. Complementation, sequencing, transgenic rescue, and RNA interference data demonstrate that this mutant eliminates a gene normally involved in repression of the hypoxia (low oxygen response) pathway. We find that up-regulation of the C. elegans hypoxia pathway via the inactivation of three different genes that normally repress the pathway results in animals resistant to Cry PFTs. Conversely, mutation in the central activator of the hypoxia response, HIF-1, suppresses this resistance and can result in animals defective in PFT defenses. These results extend to a PFT that attacks mammals since up-regulation of the hypoxia pathway confers resistance to Vibrio cholerae cytolysin (VCC), whereas down-regulation confers hypersusceptibility. The hypoxia PFT defense pathway acts cell autonomously to protect the cells directly under attack and is different from other hypoxia pathway stress responses. Two of the downstream effectors of this pathway include the nuclear receptor nhr-57 and the unfolded protein response. In addition, the hypoxia pathway itself is induced by PFT, and low oxygen is protective against PFT intoxication. These results demonstrate that hypoxia and induction of the hypoxia response protect cells against PFTs, and that the cellular environment can be modulated via the hypoxia pathway to protect against the most prevalent class of weapons used by pathogenic bacteria

    Incorporating progesterone receptor expression into the PREDICT breast prognostic model

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    Background: Predict Breast (www.predict.nhs.uk) is an online prognostication and treatment benefit tool for early invasive breast cancer. The aim of this study was to incorporate the prognostic effect of progesterone receptor (PR) status into a new version of PREDICT and to compare its performance to the current version (2.2).Method: The prognostic effect of PR status was based on the analysis of data from 45,088 European patients with breast cancer from 49 studies in the Breast Cancer Association Consortium. Cox proportional hazard models were used to estimate the hazard ratio for PR status. Data from a New Zealand study of 11,365 patients with early invasive breast cancer were used for external validation. Model calibration and discrimination were used to test the model performance.Results: Having a PR-positive tumour was associated with a 23% and 28% lower risk of dying from breast cancer for women with oestrogen receptor (ER)-negative and ER-positive breast cancer, respectively. The area under the ROC curve increased with the addition of PR status from 0.807 to 0.809 for patients with ER-negative tumours (p = 0.023) and from 0.898 to 0. 902 for patients with ER-positive tumours (p = 2.3 x 10(-6)) in the New Zealand cohort. Model calibration was modest with 940 observed deaths compared to 1151 predicted.Conclusion: The inclusion of the prognostic effect of PR status to PREDICT Breast has led to an improvement of model performance and more accurate absolute treatment benefit predic-tions for individual patients. Further studies should determine whether the baseline hazard function requires recalibration. (C) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

    Germline variants and breast cancer survival in patients with distant metastases at primary breast cancer diagnosis.

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    Breast cancer metastasis accounts for most of the deaths from breast cancer. Identification of germline variants associated with survival in aggressive types of breast cancer may inform understanding of breast cancer progression and assist treatment. In this analysis, we studied the associations between germline variants and breast cancer survival for patients with distant metastases at primary breast cancer diagnosis. We used data from the Breast Cancer Association Consortium (BCAC) including 1062 women of European ancestry with metastatic breast cancer, 606 of whom died of breast cancer. We identified two germline variants on chromosome 1, rs138569520 and rs146023652, significantly associated with breast cancer-specific survival (P = 3.19 × 10-8 and 4.42 × 10-8). In silico analysis suggested a potential regulatory effect of the variants on the nearby target genes SDE2 and H3F3A. However, the variants showed no evidence of association in a smaller replication dataset. The validation dataset was obtained from the SNPs to Risk of Metastasis (StoRM) study and included 293 patients with metastatic primary breast cancer at diagnosis. Ultimately, larger replication studies are needed to confirm the identified associations
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