241 research outputs found
Dual role of mitochondrial reactive oxygen species in hypoxia signaling: Activation of nuclear factor-κB via c-SRC- and oxidant-dependent cell death
No full textHypoxia is a prominent feature of solid tumor development and is known to stimulate mitochondrial ROS (mROS), which, in turn, can activate hypoxia-inducible transcription factor-1α and nuclear factor-κB (NF-κB). Because NF-κB plays a central role in carcinogenesis, we examined the mechanism of mROS-mediated NF-κB activation and the fate of cancer cells during hypoxia after mitochondrial reduced glutathione (mGSH) depletion. Hypoxia generated mROS in hepatoma (HepG2, H35), neuroblastoma (SH-SY5Y), and colon carcinoma (DLD-1) cells, leading to hypoxia-inducible transcription factor-1α-dependent gene expression and c-Src activation that was prevented in cells expressing a redox-insensitive c-Src mutant (C487A). c-Src stimulation activated NF-κB without IκB-α degradation due to IκB-α tyrosine phosphorylation that was inhibited by rotenone/TTFA or c-Src antagonism. The c-Src-NF-κB signaling contributed to the survival of cells during hypoxia as c-Src inhibition or p65 down-regulation by small interfering RNA-sensitized HepG2 cells to hypoxia-induced cell death. Moreover, selective mGSH depletion resulted in an accelerated and enhanced mROS generation by hypoxia that killed SH-SY5Y and DLD-1 cells without disabling the c-Src-NF-κB pathway. Thus, although mROS promote cell survival by NF-κB activation via c-Src, mROS overgeneration may be exploited to sensitize cancer cells to hypoxia. ©2007 American Association for Cancer Research.Grant support: Research Center for Liver and Pancreatic Diseases grant P50-AA11999 funded by the National Institute on Alcohol Abuse and Alcoholism; Plan Nacional de I+D Grant SAF 2006-6780; Fondo de Investigaciones Sanitarias, FISS 06/0495 and FISS 03/0426; and CIBEREHD supported by Instituto de Salud Carlos III. J.M. Lluis and A. Morales are Juan de la Cierva and Ramon y Cajal Investigators, respectively.Peer Reviewe
Narrow absorption lines from intervening material in supernovae I: measurements and temporal evolution
No full textNarrow absorption features in nearby supernova (SN) spectra are a powerful diagnostic of the slow-moving material in the line of sight: they are extensively used to infer dust extinction from the host galaxies, and they can also serve in the detection of circumstellar material originating from the SN progenitor and present in the vicinity of the explosion. Despite their wide use, very few studies have examined the biases of the methods to characterize narrow lines, and not many statistical analyses exist. This is the first paper of a series in which we present a statistical analysis of narrow lines of SN spectra of various resolutions. We develop a robust automated methodology to measure the equivalent width (EW) and velocity of narrow absorption lines from intervening material in the line of sight of SNe, including Na I D , Ca II H&K, K i and diffuse interstellar bands (DIBs). We carefully study systematic biases in heterogeneous spectra from the literature by simulating different signal-to-noise, spectral resolution, slit size and orientation and present the real capabilities and limitations of using low- and mid-resolution spectra to study these lines. In particular, we find that the measurement of the equivalent width of the narrow lines in low-resolution spectra is highly affected by the evolving broad P-Cygni profiles of the SN ejecta, both for core-collapse and type Ia SNe, inducing a conspicuous apparent evolution. We present thus an easy way to detect and exclude those cases to obtain more robust and reliable measurements. Finally, after considering all possible effects, we analyse the temporal evolution of the narrow features in a large sample of nearby SNe to detect any possible variation in their EWs over time. We find no time evolution of the narrow line features in our large sample for all SN type
A probabilistic author-centered model for Twitter discussions
No full textIn a recent work some of the authors have developed an argumentative approach for discovering relevant opinions in Twitter discussions with probabilistic valued relationships. Given a Twitter discussion, the system builds an argument graph where each node denotes a tweet and each edge denotes a criticism relationship between a pair of tweets of the discussion. Relationships between tweets are associated with a probability value, indicating the uncertainty that the relationships hold. In this work we introduce and investigate a natural extension of the representation model, referred as probabilistic author-centered model, in which tweets within a discussion are grouped by authors, in such a way that tweets of a same author describe his/her opinion in the discussion and are rep- resented with a single node in the graph, and criticism relationships denote controversies between opinions of Twitter users in the discussion. In this new model, the interactions between authors can give rise to circular criticism relationships, and the probability of one opinion criticizing another has to be evaluated from the probabilities of criticism among the tweets that compose both opinions.This work was partially funded by the Spanish MICINN Projects TIN2015-71799-C2-1-P and TIN2015-71799-C2-2-PPeer Reviewe
El pensamiento de santo Tomás de Aquino en la Encíclica Fides et ratio
No full textThe author presents the portrait of St. Thomas Aquinas following a selection of texts of the Encyclical. The harmony between faith and reason, the right autonomy of the human nature, the metaphysics of act of being (including the personal being) seem to be the ground of the recomendations of the Popes, particularly from Leo XIII to John Paul II, to study the thought of Aquinas, that was very present in the Council Vatican II
Parametrization of embedded-atom method potential for liquid lithium and lead-lithium eutectic alloy
No full textLiquid lead-lithium eutectic remains as a promising candidate for various breeding-blanket designs in future nuclear-fusion technologies. The lack of a generalized theory of interatomic forces in the liquid state is reflected on the wide variety of proposed functional forms to describe interatomic interactions even in simple liquids. Computer simulations facilitate the study of liquid metal properties, due to mathematical and experimental challenges. A classical-MD EAM potential is parametrized using mechanical and non-mechanical (melting-point) properties to minimize the arbitrariness of functional forms, where the employed pair potential stems from the liquid-state theory to avoid the issue of the uniqueness of the potential. Enhanced performance is obtained for liquid density, energy, structure, diffusivity and shear viscosity of Li, and their temperature-dependencies. In a similar manner, reference experimental and ab initio MD data are used to parametrize a functional to describe Pb-Li pairwise interactions in liquid Pb-Li alloy, which is used with the derived EAM of liquid Li and a reference EAM of liquid Pb to investigate properties of liquid Pb-Li alloy. Enhanced transferability characteristics are obtained for low-in-lithium liquid Pb-Li melts, where Coulombic interactions are negligible. In specific, the exhibited behaviour of Li in liquid lead-lithium eutectic is consistent with findings from ab initio MD methods, and drastically different from predictions of previous C-MD studies which suggested a substantial segregation of Li atoms instead of dispersion. It is concluded that the functional form of the pair potential and its uniqueness influence both the pure liquid-metal properties and the validity of the potential transferability in multi-component systems, where a theoretical functional results in enhanced performance in pure and alloyed liquid systems.We thank Dr. Jordi Marti for the discussion about the NPA potential. The first author is a holder of FI AGAUR doctoral fellowship, provided by Generalitat de Catalunya and European Social Plus Fund. This work is partially funded by the EUROfusion project (Grant Agreement No. 101052200) under the Horizon Europe programme.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe
Provenance-based trust for grid computing: Position Paper
No full textCurrent evolutions of Internet technology such as Web Services, ebXML, peer-to-peer and Grid computing all point to the development of large-scale open networks of diverse computing systems interacting with one another to perform tasks. Grid systems (and Web Services) are exemplary in this respect and are perhaps some of the first large-scale open computing systems to see widespread use - making them an important testing ground for problems in trust management which are likely to arise. From this perspective, today's grid architectures suffer from limitations, such as lack of a mechanism to trace results and lack of infrastructure to build up trust networks. These are important concerns in open grids, in which "community resources" are owned and managed by multiple stakeholders, and are dynamically organised in virtual organisations. Provenance enables users to trace how a particular result has been arrived at by identifying the individual services and the aggregation of services that produced such a particular output. Against this background, we present a research agenda to design, conceive and implement an industrial-strength open provenance architecture for grid systems. We motivate its use with three complex grid applications, namely aerospace engineering, organ transplant management and bioinformatics. Industrial-strength provenance support includes a scalable and secure architecture, an open proposal for standardising the protocols and data structures, a set of tools for configuring and using the provenance architecture, an open source reference implementation, and a deployment and validation in industrial context. The provision of such facilities will enrich grid capabilities by including new functionalities required for solving complex problems such as provenance data to provide complete audit trails of process execution and third-party analysis and auditing. As a result, we anticipate that a larger uptake of grid technology is likely to occur, since unprecedented possibilities will be offered to users and will give them a competitive edge
Entrevistes: 27 visions
No full textSumari [de les entrevistes]: 1. Joan Busquets
2. Lluis Cantallops i Valeri
3. Josep M. Carreras i Quilis
4. Jordi Casso i Smsó
5. Isabel Castiñeira i Palou
6. Miquel Corominas i Ayala
7. Juli Esteban i Noguera
8. Xabier Eizaguirre i Garagoitia
9. Ricard Fayos i Molet
10. Antoni Font i Arellano
11. Montserrat Giné i Macià
12. Sebastià Jornet i Forner
13. Carles Llop i Torné
14. Josep M. Llop i Torné
15. Juli Llueca i Fernández
16. Francesc Mestres i Angla
17. Ferran Navarro i Acebes
18. Joan A. Páez i Berga
19. Ricard Pié i Ninot
20. Manuel Ribas i Piera
21. Estanislau Roca i Blanch
22. Ramon Roger i Casamada
23. Pere Solà i Busquets
24. Manuel de Solà-Morales i Rubió
25. Jaume Torrent i Genís
26. Manuel Torres i Capell
27. Josep M. Vilanova i ClaretPostprint (published version
Entrevistes : 27 visions
No full textSumari [de les entrevistes]: 1. Joan Busquets
2. Lluis Cantallops i Valeri
3. Josep M. Carreras i Quilis
4. Jordi Casso i Smsó
5. Isabel Castiñeira i Palou
6. Miquel Corominas i Ayala
7. Juli Esteban i Noguera
8. Xabier Eizaguirre i Garagoitia
9. Ricard Fayos i Molet
10. Antoni Font i Arellano
11. Montserrat Giné i Macià
12. Sebastià Jornet i Forner
13. Carles Llop i Torné
14. Josep M. Llop i Torné
15. Juli Llueca i Fernández
16. Francesc Mestres i Angla
17. Ferran Navarro i Acebes
18. Joan A. Páez i Berga
19. Ricard Pié i Ninot
20. Manuel Ribas i Piera
21. Estanislau Roca i Blanch
22. Ramon Roger i Casamada
23. Pere Solà i Busquets
24. Manuel de Solà-Morales i Rubió
25. Jaume Torrent i Genís
26. Manuel Torres i Capell
27. Josep M. Vilanova i ClaretPostprint (published version
Entrevistes: 27 visions
No full textSumari [de les entrevistes]: 1. Joan Busquets
2. Lluis Cantallops i Valeri
3. Josep M. Carreras i Quilis
4. Jordi Casso i Smsó
5. Isabel Castiñeira i Palou
6. Miquel Corominas i Ayala
7. Juli Esteban i Noguera
8. Xabier Eizaguirre i Garagoitia
9. Ricard Fayos i Molet
10. Antoni Font i Arellano
11. Montserrat Giné i Macià
12. Sebastià Jornet i Forner
13. Carles Llop i Torné
14. Josep M. Llop i Torné
15. Juli Llueca i Fernández
16. Francesc Mestres i Angla
17. Ferran Navarro i Acebes
18. Joan A. Páez i Berga
19. Ricard Pié i Ninot
20. Manuel Ribas i Piera
21. Estanislau Roca i Blanch
22. Ramon Roger i Casamada
23. Pere Solà i Busquets
24. Manuel de Solà-Morales i Rubió
25. Jaume Torrent i Genís
26. Manuel Torres i Capell
27. Josep M. Vilanova i Clare
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