DSpace Community: Repositorio Principal

Flow and clogging in a silo with an obstacle above the orifice

Sat, 31 Dec 2011 23:00:00 GMT

Title: Flow and clogging in a silo with an obstacle above the orifice Author(s) : Lozano-Grijalba, C. (Celia); Janda-Galán, Á. (Álvaro); Garcimartín-Montero, Á. (Ángel); Maza-Ozcoidi, D. (Diego Martín); Zuriguel-Ballaz, I. (Iker)

Flow rate of particles through apertures obtained from self-similar density and velocity profiles

Sat, 31 Dec 2011 23:00:00 GMT

Title: Flow rate of particles through apertures obtained from self-similar density and velocity profiles Author(s) : Janda-Galán, Á. (Álvaro); Zuriguel-Ballaz, I. (Iker); Maza-Ozcoidi, D. (Diego Martín)

Influence of the feeding mechanism on deposits of square particles

Mon, 31 Dec 2012 23:00:00 GMT

Title: Influence of the feeding mechanism on deposits of square particles Author(s) : Acevedo-Escalante, M. (Manuel Francisco); Cruz-Hidalgo, R. (Raúl); Zuriguel-Ballaz, I. (Iker); Maza-Ozcoidi, D. (Diego Martín); Pagonabarraga, I.

Contact network topology in tapped granular media

Mon, 31 Dec 2012 23:00:00 GMT

Title: Contact network topology in tapped granular media Author(s) : Arévalo, R.; Pugnaloni, L. A.; Maza-Ozcoidi, D. (Diego Martín); Zuriguel-Ballaz, I. (Iker)

The epitopic and structural characterization of Brucella suis biovar 2 O-polysaccharide demonstrates the existence of a new M-negative C-negative smooth Brucella serovar

Mon, 31 Dec 2012 23:00:00 GMT

Title: The epitopic and structural characterization of Brucella suis biovar 2 O-polysaccharide demonstrates the existence of a new M-negative C-negative smooth Brucella serovar Author(s) : Zaccheus, M.V. (Mona V.); Ali, T. (Tara); Cloeckaert, A. (Axel); Zygmunt, M. (Michel); Weintraub, A. (Andrej); Iriarte, M. (Maite); Moriyon, I. (Ignacio); Widmalm, G. (Göran) Abstract: The brucellae are Gram-negative bacteria that cause an important zoonosis. Studies with the main Brucella species have shown that the O-antigens of the Brucella smooth lipopolysaccharide are α-(1 → 2) and α-(1 → 3)-linked N-formyl-perosamine polysaccharides that carry M, A and C (A = M, A>M and AA) and M specificities. However, the biovar 2 O-antigen bound monoclonal antibodies to the Brucella A epitope, and to the C/Y epitope shared by brucellae and Yersinia enterocolitica O:9, a bacterium that carries an N-formyl-perosamine O-antigen in exclusively α-(1 → 2)-linkages. By (13)C NMR spectroscopy, B. suis biovar 1 but not B. suis biovar 2 or Y. enterocolitica O:9 polysaccharide showed the signal characteristic of α-(1 → 3)-linked N-formyl-perosamine, indicating that biovar 2 may altogether lack this linkage. Taken together, the NMR spectroscopy and monoclonal antibody analyses strongly suggest a role for α-(1 → 3)-linked N-formyl-perosamine in the C (A = M) and C (M>A) epitopes. Moreover, they indicate that B. suis biovar 2 O-antigen lacks some lipopolysaccharide epitopes previously thought to be present in all smooth brucellae, thus representing a new brucella serovar that is M-negative, C-negative. Serologically and structurally this new serovar is more similar to Y. enterocolitica O:9 than to other brucellae.

Complexio, enunciatio, assensus: The role of propositions in knowledge according to John Buridan

Wed, 31 Dec 2003 23:00:00 GMT

Title: Complexio, enunciatio, assensus: The role of propositions in knowledge according to John Buridan Author(s) : Pérez-Ilzarbe, P. (Paloma) Abstract: This paper examines Buridan's conception of scientia as opposed to error, opinio and fides. Since scientia (as well as error, opinio and fides) is the intellectual assent to some proposition, I will try to support the hypothesis that the specific nature and structure of propositions plays an essential role in Buridan's theory of human knowledge. On the one hand, the fact that a proposition is not a mere complexio but an enunciatio, capable of being true or false, determines that human knowledge is open to error. On the other hand, since a proposition may be not only apprehended but also judged to be true, there must be some causes that move the intellect from apprehensio to assensus. Given the natural inclination of the intellect to truth, the fact that some propositions are such that they can manifest their own truth and some others are not, seems to be the explanation of why the human mind wavers between scientific knowledge and opinion, and also of the difference between science and faith. As Buridan explains the truth conditions of propositions in terms of the semantic property of suppositio, the hypothesis that propositions play a role in knowledge can be tested by examining the contribution of suppositio to the grasping of truth.

John Buridan and Jerónimo Pardo on the Notion of Propositio

Wed, 31 Dec 2003 23:00:00 GMT

Title: John Buridan and Jerónimo Pardo on the Notion of Propositio Author(s) : Pérez-Ilzarbe, P. (Paloma) Abstract: The first section offers a reconstruction of Buridan’s theory of propositions, along the following lines: on the syntactic plane, propositions obtain a special type of unity from the presence of a copula; on the semantic plane, the fact that a proposition does not have any specific significate (different from the significate of terms), does not erase the distinction between propositions and terms: the copula performs an act of “saying”, in virtue of which propositions can be true or false. The second section summarises Pardo’s theory of propositions, showing how in this case a Buridanian starting point led to a result very different from that which Buridan reached.

Brucella abortus ornithine lipids are dispensable outer membrane components devoid of a marked pathogen-associated molecular pattern

Fri, 31 Dec 2010 23:00:00 GMT

Title: Brucella abortus ornithine lipids are dispensable outer membrane components devoid of a marked pathogen-associated molecular pattern Author(s) : Palacios-Chaves, L. (Leyre); Conde-Alvarez, R. (Raquel); Gil-Ramirez, Y. (Yolanda); Zuñiga-Ripa, A. (Amaia); Barquero-Calvo, E. (Elías); Chacon-Diaz, C. (Carlos); Chaves-Olarte, E. (Esteban); Arce-Gorvel, V. (Vilma); Gorvel, J.P. (Jean Pierre); Moreno, E. (Edgardo); Miguel, M.J. (María Jesús) de; Grillo, M.J. (María Jesús); Moriyon, I. (Ignacio); Iriarte, M. (Maite) Abstract: The brucellae are α-Proteobacteria facultative intracellular parasites that cause an important zoonosis. These bacteria escape early detection by innate immunity, an ability associated to the absence of marked pathogen-associated molecular patterns in the cell envelope lipopolysaccharide, lipoproteins and flagellin. We show here that, in contrast to the outer membrane ornithine lipids (OL) of other Gram negative bacteria, Brucella abortus OL lack a marked pathogen-associated molecular pattern activity. We identified two OL genes (olsB and olsA) and by generating the corresponding mutants found that olsB deficient B. abortus did not synthesize OL or their lyso-OL precursors. Liposomes constructed with B. abortus OL did not trigger IL-6 or TNF-α release by macrophages whereas those constructed with Bordetella pertussis OL and the olsB mutant lipids as carriers were highly active. The OL deficiency in the olsB mutant did not promote proinflammatory responses or generated attenuation in mice. In addition, OL deficiency did not increase sensitivity to polymyxins, normal serum or complement consumption, or alter the permeability to antibiotics and dyes. Taken together, these observations indicate that OL have become dispensable in the extant brucellae and are consistent within the trend observed in α-Proteobacteria animal pathogens to reduce and eventually eliminate the envelope components susceptible of recognition by innate immunity.

Thermodynamic analysis of the lipopolysaccharide-dependent resistance of gram-negative bacteria against polymyxin B

Sun, 31 Dec 2006 23:00:00 GMT

Title: Thermodynamic analysis of the lipopolysaccharide-dependent resistance of gram-negative bacteria against polymyxin B Author(s) : Howe, J. (Jörg); Andrä, J. (Jörg); Conde-Alvarez, R. (Raquel); Iriarte, M. (Maite); Garidel, P. (Patrick); Koch, M.H.J. (Michel H. J.); Gutsmann, T. (Thomas); Moriyon, I. (Ignacio); Brandenburg, K. (Klaus) Abstract: Cationic antimicrobial cationic peptides (CAMP) have been found in recent years to play a decisive role in hosts' defense against microbial infection. They have also been investigated as a new therapeutic tool, necessary in particular due to the increasing resistance of microbiological populations to antibiotics. The structural basis of the activity of CAMPs has only partly been elucidated and may comprise quite different mechanism at the site of the bacterial cell membranes or in their cytoplasm. Polymyxin B (PMB) is a CAMP which is effective in particular against Gram-negative bacteria and has been well studied with the aim to understand its interaction with the outer membrane or isolated membrane components such as lipopolysaccharide (LPS) and to de. ne the mechanism by which the peptides kill bacteria or neutralize LPS. Since PMB resistance of bacteria is a long-known phenomenon and is attributed to structural changes in the LPS moiety of the respective bacteria, we have performed a thermodynamic and biophysical analysis to get insights into the mechanisms of various LPS/PMB interactions in comparison to LPS from sensitive strains. In isothermal titration calorimetric (ITC) experiments considerable differences of PMB binding to sensitive and resistant LPS were found. For sensitive LPS the endothermic enthalpy change in the gel phase of the hydrocarbon chains converts into an exothermic reaction in the liquid crystalline phase. In contrast, for resistant LPS the binding enthalpy change remains endothermic in both phases. As infrared data show, these differences can be explained by steric changes in the headgroup region of the respective LPS.

Brucellosis vaccines: assessment of Brucella melitensis lipopolysaccharide rough mutants defective in core and O-polysaccharide synthesis and export

Mon, 31 Dec 2007 23:00:00 GMT

Title: Brucellosis vaccines: assessment of Brucella melitensis lipopolysaccharide rough mutants defective in core and O-polysaccharide synthesis and export Author(s) : Gonzalez, D. (David); Grillo, M.J. (María Jesús); Miguel, M.J. (María Jesús) de; Ali, T. (Tara); Arce-Gorvel, V. (Vilma); Delrue, R.M. (Rose-May); Conde-Alvarez, R. (Raquel); Muñoz, P. (Pilar); Lopez-Goñi, I. (Ignacio); Iriarte, M. (Maite); Marin, C.M. (C. M.); Weintraub, A. (Andrej); Widmalm, G. (Göran); Zygmunt, M. (Michel); Letesson, J.J. (Jean Jacques); Gorvel, J.P. (Jean Pierre); Blasco, J.M. (J. M.); Moriyon, I. (Ignacio) Abstract: The brucellae are facultative intracellular bacteria that cause brucellosis, one of the major neglected zoonoses. In endemic areas, vaccination is the only effective way to control this disease. Brucella melitensis Rev 1 is a vaccine effective against the brucellosis of sheep and goat caused by B. melitensis, the commonest source of human infection. However, Rev 1 carries a smooth lipopolysaccharide with an O-polysaccharide that elicits antibodies interfering in serodiagnosis, a major problem in eradication campaigns. Because of this, rough Brucella mutants lacking the O-polysaccharide have been proposed as vaccines. METHODOLOGY/PRINCIPAL FINDINGS: To examine the possibilities of rough vaccines, we screened B. melitensis for lipopolysaccharide genes and obtained mutants representing all main rough phenotypes with regard to core oligosaccharide and O-polysaccharide synthesis and export. Using the mouse model, mutants were classified into four attenuation patterns according to their multiplication and persistence in spleens at different doses. In macrophages, mutants belonging to three of these attenuation patterns reached the Brucella characteristic intracellular niche and multiplied intracellularly, suggesting that they could be suitable vaccine candidates. Virulence patterns, intracellular behavior and lipopolysaccharide defects roughly correlated with the degree of protection afforded by the mutants upon intraperitoneal vaccination of mice. However, when vaccination was applied by the subcutaneous route, only two mutants matched the protection obtained with Rev 1 albeit at doses one thousand fold higher than this reference vaccine. These mutants, which were blocked in O-polysaccharide export and accumulated internal O-polysaccharides, stimulated weak anti-smooth lipopolysaccharide antibodies. CONCLUSIONS/SIGNIFICANCE: The results demonstrate that no rough mutant is equal to Rev 1 in laboratory models and question the notion that rough vaccines are suitable for the control of brucellosis in endemic areas.

The lipopolysaccharide core of Brucella abortus acts as a shield against innate immunity recognition

Sat, 31 Dec 2011 23:00:00 GMT

Title: The lipopolysaccharide core of Brucella abortus acts as a shield against innate immunity recognition Author(s) : Conde-Alvarez, R. (Raquel); Arce-Gorvel, V. (Vilma); Iriarte, M. (Maite); Mancek-Keber, M. (Mateja); Barquero-Calvo, E. (Elías); Palacios-Chaves, L. (Leyre); Chacon-Diaz, C. (Carlos); Chaves-Olarte, E. (Esteban); Martirosyan, A. (Anna); Bargen, K. (Kristine) von; Grillo, M.J. (María Jesús); Jerala, R. (Roman); Brandenburg, K. (Klaus); Llobet, E. (Enrique); Bengoechea, J.A. (José A.); Moreno, E. (Edgardo); Moriyon, I. (Ignacio); Gorvel, J.P. (Jean Pierre) Abstract: Innate immunity recognizes bacterial molecules bearing pathogen-associated molecular patterns to launch inflammatory responses leading to the activation of adaptive immunity. However, the lipopolysaccharide (LPS) of the gram-negative bacterium Brucella lacks a marked pathogen-associated molecular pattern, and it has been postulated that this delays the development of immunity, creating a gap that is critical for the bacterium to reach the intracellular replicative niche. We found that a B. abortus mutant in the wadC gene displayed a disrupted LPS core while keeping both the LPS O-polysaccharide and lipid A. In mice, the wadC mutant induced proinflammatory responses and was attenuated. In addition, it was sensitive to killing by non-immune serum and bactericidal peptides and did not multiply in dendritic cells being targeted to lysosomal compartments. In contrast to wild type B. abortus, the wadC mutant induced dendritic cell maturation and secretion of pro-inflammatory cytokines. All these properties were reproduced by the wadC mutant purified LPS in a TLR4-dependent manner. Moreover, the core-mutated LPS displayed an increased binding to MD-2, the TLR4 co-receptor leading to subsequent increase in intracellular signaling. Here we show that Brucella escapes recognition in early stages of infection by expressing a shield against recognition by innate immunity in its LPS core and identify a novel virulence mechanism in intracellular pathogenic gram-negative bacteria. These results also encourage for an improvement in the generation of novel bacterial vaccines.

The differential interaction of Brucella and Ochrobactrum with innate immunity reveals traits related to the evolution of stealthy pathogens

Wed, 31 Dec 2008 23:00:00 GMT

Title: The differential interaction of Brucella and Ochrobactrum with innate immunity reveals traits related to the evolution of stealthy pathogens Author(s) : Barquero-Calvo, E. (Elías); Conde-Alvarez, R. (Raquel); Chacon-Diaz, C. (Carlos); Quesada-Lobo, L. (Lucía); Martirosyan, A. (Anna); Guzman-Verri, C. (Caterina); Iriarte, M. (Maite); Mancek-Keber, M. (Mateja); Jerala, R. (Roman); Gorvel, J.P. (Jean Pierre); Moriyon, I. (Ignacio); Moreno, E. (Edgardo); Chaves-Olarte, E. (Esteban) Abstract: Background: During evolution, innate immunity has been tuned to recognize pathogen-associated molecular patterns. However, some alpha-Proteobacteria are stealthy intracellular pathogens not readily detected by this system. Brucella members follow this strategy and are highly virulent, but other Brucellaceae like Ochrobactrum are rhizosphere inhabitants and only opportunistic pathogens. To gain insight into the emergence of the stealthy strategy, we compared these two phylogenetically close but biologically divergent bacteria. Methodology/principal Findings: In contrast to Brucella abortus, Ochrobactrum anthropi did not replicate within professional and non-professional phagocytes and, whereas neutrophils had a limited action on B. abortus, they were essential to control O. anthropi infections. O. anthropi triggered proinflammatory responses markedly lower than Salmonella enterica but higher than B. abortus. In macrophages and dendritic cells, the corresponding lipopolysaccharides reproduced these grades of activation, and binding of O. anthropi lipopolysaccharide to the TLR4 co-receptor MD-2 and NF-kappaB induction laid between those of B. abortus and enteric bacteria lipopolysaccharides. These differences correlate with reported variations in lipopolysaccharide core sugars, sensitivity to bactericidal peptides and outer membrane permeability. Conclusions/significance: The results suggest that Brucellaceae ancestors carried molecules not readily recognized by innate immunity, so that non-drastic variations led to the emergence of stealthy intracellular parasites. They also suggest that some critical envelope properties, like selective permeability, are profoundly altered upon modification of pathogen-associated molecular patterns, and that this represents a further adaptation to the host. It is proposed that this adaptive trend is relevant in other intracellular alpha-Proteobacteria like Bartonella, Rickettsia, Anaplasma, Ehrlichia and Wolbachia.

Acceso abierto y visibilidad de la investigación. El caso de Dadun, Depósito Digital de la Universidad de Navarra

Wed, 12 Jun 2013 22:00:00 GMT

Title: Acceso abierto y visibilidad de la investigación. El caso de Dadun, Depósito Digital de la Universidad de Navarra Author(s) : Eslava, S. (Salomé); Itúrbide-Tellechea, M.A. (Mª Arántzazu) Abstract: Comunicación presentada en el Congreso «Humanidades digitales: visibilidad y difusión de la investigación», celebrado en Pamplona los días 23 y 24 de mayo de 2013. La presentación la realizaron Salomé Eslava y Arantxa Iturbide, del Servicio de Biblioteca de la Univeridad de Navarra.

Lifestyles and risk factors associated with adherence to the Mediterranean diet: a baseline assessment of the PREDIMED trial

Mon, 31 Dec 2012 23:00:00 GMT

Title: Lifestyles and risk factors associated with adherence to the Mediterranean diet: a baseline assessment of the PREDIMED trial Author(s) : Hu, E.A. (Emily A.); Toledo, E. (Estefanía); Diez-Espino, J. (J.); Estruch, R. (R.); Corella, D. (Dolores); Salas-Salvado, J. (Jordi); Vinyoles, E. (Ernest); Gómez-Gracia, E. (Enrique); Aros, F. (F.); Fiol, M. (M.); Lapetra, J. (José); Serra-Majem, L. (Lluis); Pinto, X. (Xavier); Portillo, M.P. (María P.); Lamuela-Raventos, R.M. (Rosa María); Ros, E. (Emilio); Sorli, J.V. (José V.); Martinez-Gonzalez, M.A. (Miguel Angel) Abstract: Background: The traditional Mediterranean dietary pattern (MedDiet) is associated with longevity and low rates of cardiovascular disease (CVD). However, there is little information on who is more likely to follow this food pattern. Aim: To evaluate how different factors are associated with lower MedDiet adherence in older Spanish subjects. Methods: We included 7305 participants (men aged 55-80 y, women 60-80 y) at high-risk of CVD recruited into the PREDIMED trial (ISRCTN35739639). Socioeconomic, anthropometric, lifestyle characteristics and CVD risk factors were recorded. A validated 14-item questionnaire was used to evaluate MedDiet adherence at baseline. Multivariate models were used to estimate odds ratios (OR) and 95% confidence intervals for lower adherence to the MedDiet (<9 points out of 14) and ascertain factors independently associated with it. Results: Former smoking (OR = 0.87; 95% CI, 0.78-0.98), physical activity (OR for the 3(rd) vs. the 1(st)tertile: 0.69; 0.62-0.78), and higher educational level (OR for university vs. less than primary school: 0.54; 0.38-0.77) were associated with higher MedDiet adherence. Conversely, having a larger waist-to-height ratio (OR for 0.1 units, 1.35; 1.22-1.49), being diabetic (OR = 1.13; 1.03-1.24), being single (OR = 1.27; 1.01-1.61) or divorced or separated (OR = 1.44; 1.09-1.89), and current smoking (OR = 1.28; 1.11-1.47) were associated with lower adherence. Conclusions: Participants with little education, a larger waist-to-height ratio, or diabetes and those who were less physically active, single, divorced or separated, or smokers were less likely to adhere to the MedDiet, an ideal model for food choices. Stronger efforts of health promotion are needed in these groups to foster adoption of the MedDiet.

Características y valor de las aberraciones cromosómicas inducidas por los tratamientos antitumorales en pacientes pediátricos con cáncer

Fri, 31 Dec 1999 23:00:00 GMT

Title: Características y valor de las aberraciones cromosómicas inducidas por los tratamientos antitumorales en pacientes pediátricos con cáncer Author(s) : Lopez-de-la-Mesa, R. (R.); Sierrasesumaga, L. (Luis); Calasanz, M.J. (María José); Lopez-de-Cerain, A. (Adela); Patiño, A. (Ana) Abstract: Cytogenetic studies were performed on 80 pediatric cancer patients to test the chromosomal damage induced by the chemotherapy treatments. G-banded karyotypes were performed on peripheral blood lymphocytes (PBL) (n = 127) obtained at diagnosis, during treatment, at remission and at relapse. We detected a significant increase in the number of altered karyotypes in the samples during treatment, lowering to similar values to those at diagnosis at two-year remission. Most of the chromosomal aberrations (CA) detected during chemotherapy were unbalanced (75%) and affected most frequently chromosomes 1, 3, 5, 6, 11, 12, 16 and 17. There was also a marked increase of CA in samples at relapse, with similar features (type and distribution) to those detected during treatment. There was an outstanding correlation between the chromosomal breakpoints in our series and fragile sites (58%), oncogene (75%) and tumour suppressor gene (33%) loci described in the literature. The results obtained suggest that the cytostatic drugs induce a transient increase in chromosome fragility that focuses to several cancer-associated breakpoints.