428 research outputs found
Forage biomass estimation using sentinel-2 imagery at high latitudes
Forages are the most important kind of crops at high latitudes and are the main feeding source for ruminant-based dairy industries. Maximizing the economic and ecological performances of farms and, to some extent, of the meat and dairy sectors require adequate and timely supportive field-specific information such as available biomass. Sentinel-2 satellites provide open access imagery that can monitor vegetation frequently. These spectral data were used to estimate the dry matter yield (DMY) of harvested forage fields in northern Sweden. Field measurements were conducted over two years at four sites with contrasting soil and climate conditions. Univariate regression and multivariate regression, including partial least square, support vector machine and random forest, were tested for their capability to accurately and robustly estimate in-season DMY using reflectance values and vegetation indices obtained from Sentinel-2 spectral bands. Models were built using an iterative (300 times) calibration and validation approach (75% and 25% for calibration and validation, respectively), and their performances were formally evaluated using an independent dataset. Among these algorithms, random forest regression (RFR) produced the most stable and robust results, with Nash–Sutcliffe model efficiency (NSE) values (average ± standard deviation) for the calibration, validation and evaluation of 0.92 ± 0.01, 0.55 ± 0.22 and 0.86 ± 0.04, respectively. Although relatively promising, these results call for larger and more comprehensive datasets as performances vary largely between calibration, validation and evaluation datasets. Moreover, RFR, as any machine learning algorithm regression, requires a very large dataset to become stable in terms of performance
El tratamiento con 5azadC regula al alza el nivel de miR-375 y reprime la expresión de HPV16 E6
High-risk human papillomaviruses are the etiological agents of cervical cancer and HPV16 is the most oncogenic genotype. Immortalization and transformation of infected cells requires the overexpression of the two viral oncoproteins E6 and E7 following HPV DNA integration into the host cell genome. Integration often leads to the loss of the E2 open reading frame and the corresponding protein can no longer act as a transcriptional repressor on p97 promoter. Recently, it has been proposed that long control region methylation also contributes to the regulation of E6/E7 expression. To determine which epigenetic mechanism is involved in HPV16 early gene regulation, 5-aza-2?-deoxycytidine was used to demethylate Ca Ski and SiHa cell DNA. Decreased expression of E6 mRNA and protein levels was observed in both cell lines in an E2-independent manner. E6 repression was accompanied by neither a modification of the main cellular transcription factor expression involved in long control region regulation, nor by a modification of the E6 mRNA splicing pattern. In contrast, a pronounced upregulation of miR-375, known to destabilize HPV16 early viral mRNA, was observed. Finally, the use of miR-375 inhibitor definitively proved the involvement of miR-375 in E6 repression. These results highlight that cellular DNA methylation modulates HPV16 early gene expression and support a role for epigenetic events in high-risk HPV associated-carcinogenesis
Cells
The earliest effect of spaceflight is an alteration in vestibular function due to microgravity. Hypergravity exposure induced by centrifugation is also able to provoke motion sickness. The blood-brain barrier (BBB) is the crucial interface between the vascular system and the brain to ensure efficient neuronal activity. We developed experimental protocols of hypergravity on C57Bl/6JRJ mice to induce motion sickness and reveal its effects on the BBB. Mice were centrifuged at 2× for 24 h. Fluorescent dextrans with different sizes (40, 70 and 150 kDa) and fluorescent antisense oligonucleotides (AS) were injected into mice retro-orbitally. The presence of fluorescent molecules was revealed by epifluorescence and confocal microscopies in brain slices. Gene expression was evaluated by RT-qPCR from brain extracts. Only the 70 kDa dextran and AS were detected in the parenchyma of several brain regions, suggesting an alteration in the BBB. Moreover, Ctnnd1, Gja4 and Actn1 were upregulated, whereas Jup, Tjp2, Gja1, Actn2, Actn4, Cdh2 and Ocln genes were downregulated, specifically suggesting a dysregulation in the tight junctions of endothelial cells forming the BBB. Our results confirm the alteration in the BBB after a short period of hypergravity exposure
Staging of nutrition disorders in non-small-cell lung cancer patients : utility of skeletal muscle mass assessment
Background An international consensus proposed in 2011 a definition and classification system for cachexia (CAX), mainly based on weight loss, sarcopenia [skeletal muscle mass (SMM) loss], inflammation, and anorexia. The aim of this study was to stage CAX in non-small-cell lung cancer (NSCLC) patients by using a classification based on the Fearon criteria and supported by quantifiable parameters. Methods This was a cross-sectional and non-interventional multicentre study. SMM was assessed by analysing L3 computed tomography-scan images. Patients completed the anorexia/CAX subscale of the Functional Assessment of Anorexia/Cachexia Therapy, EORTC QLQ-C30 quality of life (QoL) and International Physical Activity Questionnaire (IPAQ). Results Patients were recruited in 56 sites. The analysis population comprised 531 patients, and SMM was assessed in 312 patients. Male patients were 66.5%, with a mean (SD) age of 65.2 (10.0) years, 79.9% were PS 0-1, and the tumour stage was mainly IIIB-IV (87.3%). Overall, 38.7% of patients had CAX, 33.8% pre-CAX, and 0.9% refractory CAX. Molecular tumour profiles were significantly associated with the presence of CAX: 23.9% in EGFR, ALK, ROS1, BRAF, or HER2+ patients, 41.4% in K-RAS+, and 43.2% in patients with no molecular abnormality (P = 0.003). The more advanced the CAX stage, the poorer the scores of functional items of the QoL (P < 0.001) and International Physical Activity Questionnaire (P < 0.001). Sarcopenia was present in 66.7% of CAX and 68.5% of pre-CAX patients. Overall, 43.8% of pre-CAX patients had only sarcopenia with limited weight loss (<= 2%) and no anorexia. Conclusions This is the first study to show the distribution of CAX in a population of NSCLC patients and an association between molecular abnormality in NSCLC and CAX. The original Fearon classification for CAX stages was supported by the associated functional QoL scores and physical activity levels, resulting in a clinically relevant system for detection of early stages of CAX
DNA demethylation agent 5azadC downregulates HPV16 E6 expression in cervical cancer cell lines independently of TBX2 expression
HPV16 is the most carcinogenic human papillomavirus and causes >50% of cervical cancers, the majority of anal cancers and 30% of oropharyngeal squamous cell carcinomas. HPV carcinogenesis relies on the continuous expression of the two main viral oncoproteins E6 and E7 that target >150 cellular proteins. Among them, epigenetic modifiers, including DNA Methyl Transferases (DNMT), are dysregulated, promoting an aberrant methylation pattern in HPV-positive cancer cells. It has been previously reported that the treatment of HPV-positive cervical cancer cells with DNMT inhibitor 5-aza-2'-deoxycytidine (5azadC) caused the downregulation of E6 expression due to mRNA destabilization that was mediated by miR-375. Recently, the T-box transcription factor 2 (TBX2) has been demonstrated to repress HPV LCR activity. In the current study, the role of TBX2 in E6 repression was investigated in HPV16 cervical cancer cell lines following 5azadC treatment. A decrease of E6 expression was accompanied by p53 and p21 restoration. While TBX2 mRNA was upregulated in 5azadC-treated SiHa and Ca Ski cells, TBX2 protein was not detectable. Furthermore, the overexpression of TBX2 protein in cervical cancer cells did not allow the repression of E6 expression. The TBX2 transcription factor is therefore unlikely to be associated with the repression of E6 following 5azadC treatment of SiHa and Ca Ski cells. © 2020 Spandidos Publications. All rights reserved
"SARGOS" : Système d'Alerte et Réponse Graduée Off Shore
International audienceLe projet SARGOS répond à l'émergence du besoin de sûreté des infrastructures offshore civiles vulnérables aux actes de malveillance, de piraterie ou de terrorisme menées à partir de la mer. Il propose le développement d'un système assurant de manière coordonnée la chaîne globale de protection : veille et surveillance automatisées ; détection d'intrusion ; évaluation de dangerosité ; plan de réaction gradué et piloté en temps réel pour rester constamment adapté au niveau de menace représenté par l'intrusion détectée. Une des capacités clefs est l'élaboration d'une stratégie complète et mutualisée de défense, incluant la mise en sûreté des personnes, la diffusion de l'alarme, la coordination des moyens d'assistance extérieure et la mise en oeuvre de moyens de dissuasion non létaux pour apporter une réponse complète à la menace. Un démonstrateur du système SARGOS illustrant toute la chaîne de protection a été déployé sur site pour des expérimentations en vraie grandeur selon des scénarios définis avec les opérationnels. Les essais ont permis de valider tous les points clefs : détection de petites embarcations - levée d'alertes pertinentes couplant analyse de comportement des embarcations et évaluation de dangerosité - Assistance intuitive à l'opérateur pour l'activation de procédures de réaction proposées en dynamique suivant une logique prédéfinie propre aux moyens disponibles
Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations
We present a method to confirm the planetary nature of objects in systems
with multiple transiting exoplanet candidates. This method involves a
Fourier-Domain analysis of the deviations in the transit times from a constant
period that result from dynamical interactions within the system. The
combination of observed anti-correlations in the transit times and mass
constraints from dynamical stability allow us to claim the discovery of four
planetary systems Kepler-25, Kepler-26, Kepler-27, and Kepler-28, containing
eight planets and one additional planet candidate.Comment: Accepted to MNRA
Genetic and dietary modulators of the inflammatory response in the gastrointestinal tract of the BXD mouse genetic reference population.
peer reviewedInflammatory gut disorders, including inflammatory bowel disease (IBD), can be impacted by dietary, environmental, and genetic factors. While the incidence of IBD is increasing worldwide, we still lack a complete understanding of the gene-by-environment interactions underlying inflammation and IBD. Here, we profiled the colon transcriptome of 52 BXD mouse strains fed with a chow or high-fat diet (HFD) and identified a subset of BXD strains that exhibit an IBD-like transcriptome signature on HFD, indicating that an interplay of genetics and diet can significantly affect intestinal inflammation. Using gene co-expression analyses, we identified modules that are enriched for IBD-dysregulated genes and found that these IBD-related modules share cis-regulatory elements that are responsive to the STAT2, SMAD3, and REL transcription factors. We used module quantitative trait locus analyses to identify genetic loci associated with the expression of these modules. Through a prioritization scheme involving systems genetics in the mouse and integration with external human datasets, we identified Muc4 and Epha6 as the top candidates mediating differences in HFD-driven intestinal inflammation. This work provides insights into the contribution of genetics and diet to IBD risk and identifies two candidate genes, MUC4 and EPHA6, that may mediate IBD susceptibility in humans
System Vicarious Calibration for Ocean Color Climate Change Applications: Requirements for In Situ Data
System Vicarious Calibration (SVC) ensures a relative radiometric calibration to satellite ocean color sensors that minimizes uncertainties in the water-leaving radiance Lw derived from the top of atmosphere radiance LT. This is achieved through the application of adjustment gain-factors, g-factors, to pre-launch absolute radiometric calibration coefficients of the satellite sensor corrected for temporal changes in radiometric sensitivity. The g-factors are determined by the ratio of simulated to measured spectral LT values where the former are computed using: i. highly accurate in situ Lw reference measurements; and ii. the same atmospheric model and algorithms applied for the atmospheric correction of satellite data. By analyzing basic relations between relative uncertainties of Lw and LT, and g-factors consistently determined for the same satellite missions using different in situ data sources, this work suggests that the creation of ocean color Climate Data Records (CDRs) should ideally rely on: i. one main long-term in situ calibration system (site and radiometry) established and sustained with the objective to maximize accuracy and precision over time of g-factors and thus minimize possible biases among satellite data products from different missions; and additionally ii. unique (i.e., standardized) atmospheric model and algorithms for atmospheric correction to maximize cross-mission consistency of data products at locations different from that supporting SVC. Finally, accounting for results from the study and elements already provided in literature, requirements and recommendations for SVC sites and field radiometers radiometric measurements are streamlined
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