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Search Results: 1 - 10 of 9751 matches for " Pablo; Echave "
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Textbook of Structural Biology by Anders Liljas, Lars Liljas, Jure Piskur, G ran Lindblom, Poul Nissen, and Morten Kjeldgaard
Julian Echave
Trends in Evolutionary Biology , 2009, DOI: 10.4081/eb.2009.e2
Abstract: Textbook of Structural Biology By Anders Liljas, Lars Liljas, Jure Piskur, G ran Lindblom, Poul Nissen, and Morten Kjeldgaard Publisher: World Scientific Publishing Co. Pte. Ltd. Number of Pages: 572 Publication Year: 2009 ISBN-10: 981-277-208-1 ISBN-13: 978-981-277-208-4 Binding: Paperback
Absceso del septum nasal
Barril,María F; Ferolla,Fausto M; José,Pablo; Echave,Cecilia; Tomezzoli,Silvana; Fiorini,Sandra; López,Eduardo Luis;
Archivos argentinos de pediatr?-a , 2008,
Abstract: a nasal septal abscess (na) is defined as a collection of pus between the cartilage or bony septum and its normally applied mucoperichondrium or mucoperiostium. it is an uncommon disease wich should be suspected in a patient with acute onset of nasal obstruction and recent history of nasal trauma, periodontal infection or an inflammatory process of the rhinosinusal region. we report a case of an 8-year-old boy with bilateral na caused by community-acquired methicillin-resistant staphylococcus aureus(mr-co) in order to emphasize the importance of prompt diagnosis and adequate treatment to prevent the potentially dangerous spread of infection and the development of severe functional and cosmetic sequelae.
The structurally constrained protein evolution model accounts for sequence patterns of the LβH superfamily
Gustavo Parisi, Julián Echave
BMC Evolutionary Biology , 2004, DOI: 10.1186/1471-2148-4-41
Abstract: We studied site-dependent entropies, amino acid probability distributions, and substitution matrices predicted by SCPE and compared with experimental data for several members of the LβH superfamily. We also evaluated structure conservation during simulations. Overall, SCPE outperforms JTT in the description of sequence patterns observed in structurally constrained sites. Maximum Likelihood calculations show that the local-score and global-score SCPE substitution matrices obtained for LPXA outperform the JTT model for the LPXA family and for the structurally constrained sites of class i of other members within the LβH superfamily.We extended the SCPE model by introducing a new scoring function, the local score. We performed a thorough assessment of the SCPE model on the LPXA family and extended it to all other members of known structure of the LβH superfamily.Protein structure is more conserved than protein sequence during molecular evolution [1-3]. Remote homologous proteins constitute an extreme example of sequence divergence where proteins with similar function and no apparent sequence similarity present almost the same fold [4]. However, protein sequences are far from being random. Rather, they are selected through evolution in such a way that functional constraints modulate sequence variability. Usually, only a few residues are directly related to the protein function. However, these residues must maintain adequate spatial relationships for the protein to remain functional, so that the whole 3D structure is conserved. In turn, structure conservation constrains sequence variability in such a way that residue substitution does not disturb the overall 3D structure of the protein. This results in emergent non-random sequence patterns.The restrictions imposed by the environment of a given protein site onto its pattern of amino acid substitutions have been largely discussed [2,5-9]. Briefly, highly constrained positions are more conserved. Furthermore, each site has a
Assessing local structural perturbations in proteins
Martin A Lema, Julian Echave
BMC Bioinformatics , 2005, DOI: 10.1186/1471-2105-6-226
Abstract: We have developed an algorithm to compare local structural differences between alternative structures of the same protein. We have implemented the algorithm through a computer program that performs the numerical evaluation and allows inspecting visually the results of the structure comparison. We have tested the algorithm on different kinds of model systems. Here we present the algorithm and some results to illustrate its characteristics.This program may provide an insight into the local structural changes produced in a protein structure by different interactions or modifications. It is convenient for the general user and it can be applied to standard or specific tasks on protein structure research.Localized perturbations in a protein structure can originate from point mutations, chemical modifications, interaction with other molecules, etc. Sometimes, it is necessary to compare alternative structures for the same protein sequence (e.g. different three-dimensional structure predictions, multiple models from NMR studies, etc.). To assess such protein structural perturbations, structures are usually compared in a detailed way, by looking at the position and orientation of individual atoms, residues, or secondary structures (for instance, see [1]). This approach is mandatory on case studies, because it leads to explain how modifications have changed the structure and function of a protein. However, this kind of comparison is usually done by superposing different particular structure elements individually and/or by using different protein-specific frames of reference, which are chosen according to the expertise and personal criteria of the researcher. This complicates establishing generalizations applicable to different proteins and the analysis of large numbers of cases. For such situations, quantitative measures of structural perturbation, such as the root mean square deviation (RMSd) or a derivative function [2-4], are used.RMSd is a measure that is simple to calcula
Nonadiabatic Calculation of Dipole Moments
Francisco M. Fernández,Julián Echave
Physics , 2009,
Abstract: We review some of the few available nonadiabatic calculations of dipole moments. We show that those carried out in a laboratory-fixed set of coordinate axes are bound to fail and discuss the more reasonable ones in a molecule-fixed reference frame. For completeness we also describe the standard Born--Oppenheimer calculations of dipole moments. We briefly address the experimental estimation of dipole moments from the Stark shift of spectral lines and argue that it does not provide such property but a sort of energy--weighted average of dipole transition moments.
Strumenti di valutazione della resilienza urbana. Assessment instruments of urban resilience
Giovanna Saporiti,Cynthia Echave,Gianni Scudo,Salvador Rueda
TeMA : Journal of Land Use, Mobility and Environment , 2012, DOI: 10.6092/1970-9870/924
Abstract: L'obiettivo dell'approfondimento è di porre in evidenza quali siano gli aspetti legati alla capacità resiliente di un neoecosistema. Avendo infatti chiaro cosa voglia dire parlare di un neocosostema resiliente e quali siano i caratteri specifici che lo rendono capace di adattarsi e modificarsi in seguito ad una minaccia ambientale, sociale o economica, sarà possibile comprenderne l'efficacia rispetto all'attuale modello di sviluppo urbano. Partendo quindi dall'individuazione dei fattori di perturbazione di questa capacità, verrà approfondito un pannello di valutazione della capacità resiliente rispetto a tre distinti ambiti, che rappresentano i tre elementi caratteristici degli ecosistemi naturali: la struttura fisica dello stesso, le persone e i processi di interazione tra i due, in modo da poter esplicitare con chiarezza quali siano i caratteri specifici della resilienza rispetto al sostenibilità e alla qualità urbana. The objective of this work is to highlight the aspects related to the resilient capacity of a neoecosistema. Clarifying what does it means to speak about a resilient neoecosistema and which are the specific characters that make him capable of change and adaptation when facing an environmental, social or economic threat, it will be possible to understand the efficacy related to the model of urban development. From the individuation of perturbing factors of this capacity, it will be possible to generate a panel of the resilient capacity linked to three different ambits that represent the three characteristic elements of natural ecosystems: its physic structure, the persons and the interaction processes between them so we would be able to make explicit the specific characters of resilience distinguished from those of sustainability and urban quality.
Annual survival of Red Knots (Calidris canutus rufa) using the San Antonio Oeste stopover site is reduced by domino effects involving late arrival and food depletion in Delaware Bay
González,Patricia M.; Baker,Allan J.; Echave,María Eugenia;
El hornero , 2006,
Abstract: ecological conditions in breeding and non-breeding areas of migrant birds have been linked to their annual survival and production of young, but the role of stopover sites is under-appreciated. through banding studies and censuses along the flyway from tierra del fuego to the canadian arctic, the drastic decline in 2000-2001 of red knots (calidris canutus rufa) population summering in southern south america in the northern winter was shown to be related to the overharvesting of horseshoe crabs (limulus polyphemus) in delaware bay, usa, their last stopover site before reaching their breeding grounds, and to the late arrival of the birds at this site. in san antonio oeste, argentina, where 25-50% of the tierra del fuego red knots population congregates every northward migration season, annual survival of the cohort of experienced birds banded in march 1998 was impacted a year later than the general decline. knots marked at san antonio oeste earlier in march arrived in delaware bay on average before those marked 15 days later. additionally, early migrating knots with active body moult in san antonio oeste exhibited a higher return rate in the following years than late and non-moulting birds. since the decline, birds arriving late in delaware bay have been at increased risk of not being able to refuel properly or on time because food is no longer superabundant at that stopover site. these domino effects indicate that there are fitness consequences to individual migration strategies adopted by birds at austral summering and stopover sites, which can be amplified by compressed timing in delaware bay when food is depleted at this final stopover site.
Artritis meningocócica primaria en pediatría: Presentación de nueve casos
Sordelli,Nora; Orlando,Nancy; Neyro,Silvina; Echave,Cecilia; Procopio,Adriana; Fallo,Aurelia; López,Eduardo L;
Archivos argentinos de pediatr?-a , 2011,
Abstract: primary meningococcal arthritis is an extremely uncommon type of invasive meningoccal disease, with an incidence of 1.5- 1.8% of all paediatric cases of pyogenic arthritis. it is defined as the presence of acute septic arthritis without association with meningitis or the classic meningococcaemia, and isolation of neisseria meningitidis in synovial fluid and/or blood culture. typically monoarticular, mostly affects large joints. prognosis is excellent with appropriated treatment. the aim of this study is to report 9 cases of primary meningococcal arthritis, evaluated at hospital de ni?os "dr. r. gutiérrez" in a period of 3 years, and to discuss clinical and epidemiologic issues.
Compromiso mamario bilateral por leucemia linfocítica aguda. Hallazgos por mamografía, ultrasonido y resonancia magnética: Presentación de un caso Bilateral breast involvement in acute lymphoblastic leukemia. Mammographic, ultrasound and magnetic resonance imaging findings: Case report
Javier Rodríguez Lucero,Marcelo García Arnedo,Gabriela Echave,Carolina Espinosa
Revista Argentina de Radiología , 2013,
Abstract: Presentamos el caso de una paciente de 26 a os de edad con antecedente de leucemia linfocítica aguda, tratada con quimioterapia y trasplante de médula ósea, que consultó por nódulos palpables en ambas mamas. Se estudió mediante mamografía, ultrasonido (US) y resonancia magnética (RM), y el diagnóstico anatomopatológico final fue una recaída de la enfermedad de base por compromiso mamario. El caso resulta de interés, ya que se trata de una forma de manifestación muy poco habitual, con escasos reportes en la literatura y ningún trabajo encontrado en el que se describa la utilidad de la resonancia magnética en estos pacientes. We report a case of a 26-year-old girl with acute lymphoblastic leukemia treated with chemotherapy and bone marrow transplant who presented with palpable lumps in both breasts. Mammography, ultrasound and magnetic resonance imaging were performed, with the final pathological diagnosis being relapse of her underlying disease with breast involvement. The case is worth reporting because it is a very unusual form of presentation, with few reports in medical literature, having found no previous studies discussing the usefulness of magnetic resonance imaging in these cases.
Environmental stress upon hepatopancreatic cells of freshwater prawns (Decapoda: Caridea) from the floodplain of Paraná River  [PDF]
Pablo Collins
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.27094
Abstract: In order to evaluate the influence of stressed environments on hepatopancreatic cells of fre- shwater prawns, Macrobachium borellii Nobili, 1896 and Palaemonetes argentinus Nobili 1901, (Crustacea, Decapoda, Palaemonidae) were collected at three different aquatic environments with different relationship to urban development in Argentina. Furthermore the effects of several cypermethryn concentration on hepa- topancreatic cell of M. borellii and P. argentinus were evaluated in a laboratory assays. The “N° 1” lake (Santa Fe Argentina) which is more affected by the anthropogenic pressure and “Don Felipe” lake which is still not strongly by human activities were the studied sites from the floodplain of Paraná river. While Alejandra lake was the intermedia effects sites. Different damaged ultra-structures were found in F- and R-cells of prawns in the stressed lake. The predominant features were: disrupted the microvillous border, swelled mitochondria, reduction of endoplasmic reticulum, dyctiosomes, glycoproteins, desna-turalization of vacuole membrane and premature autolysis. Moreover the F-cell number was higher in the environment near to city than in the others sites. Similar effects were observed in the cypermethryn assays. The observations clearly indicate that the ultrastructure of midgut gland in the both palaemonids varies depending on the site from which animals are collected and the biocid presence. So, in this case it can be stated that the hepatopancreas histology of fre- shwater prawns is a good tool to monitor the impact of a stressed environment upon freshwater prawns.
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