26 research outputs found
Estudio y diseño mecánico mediante elementos finitos del comportamiento de mallas biocompatibles para un dispositivo de asistencia ventricular.
Estudio y diseño de un entorno computacional mediante elementos finitos para analizar el comportamiento mecánico de un dispositivo de asistencia ventricular (VAD) basado en una malla celularizada. Para ello se considerarán diferentes alternativas de diseño de malla, considerando varias geometrías de poro así como diversas modificaciones geométricas dentro de cada patrón, con el objetivo de optimizar su diseño desde el punto de vista mecánico.<br /
Primera detección de Lonsdalea quercina subsp. populi en chopo en España
Lonsdalea quercina (ex Brenneria quercina) subsp. populi es una bacteria recientemente
identificada en Hungría y China como una nueva subespecie causante del chancro de la corteza
del chopo. Los árboles afectados presentan chancros longitudinales en el tronco, de los que
fluyen abundantes exudados espumosos de color blanco y exudados acuosos oscuros que tiñen
la corteza. Los chopos afectados muestran un debilitamiento generalizado.
En España se han localizado choperas con síntomas similares y se ha identificado L. quercina
subsp. populi como el agente causal de los mismos. En este trabajo se presenta la primera
detección de esta bacteria en España y se describen los métodos de diagnóstico e identificación
utilizados. Esta nueva bacteriosis podría tener un impacto económico importante, siendo
necesario evaluar las pérdidas causadas y realizar nuevas prospecciones para determinar su
distribución en el país
Primera detección de Lonsdalea quercina subsp. populi en chopo en España
Lonsdalea quercina (ex Brenneria quercina) subsp. populi es una bacteria recientemente
identificada en Hungría y China como una nueva subespecie causante del chancro de la corteza
del chopo. Los árboles afectados presentan chancros longitudinales en el tronco, de los que
fluyen abundantes exudados espumosos de color blanco y exudados acuosos oscuros que tiñen
la corteza. Los chopos afectados muestran un debilitamiento generalizado.
En España se han localizado choperas con síntomas similares y se ha identificado L. quercina
subsp. populi como el agente causal de los mismos. En este trabajo se presenta la primera
detección de esta bacteria en España y se describen los métodos de diagnóstico e identificación
utilizados. Esta nueva bacteriosis podría tener un impacto económico importante, siendo
necesario evaluar las pérdidas causadas y realizar nuevas prospecciones para determinar su
distribución en el país
First Report of Bark Canker Disease of Poplar Caused by Lonsdalea quercina subp. populi in Spain
Symptoms of a bacterial disease were observed in nine plantations of hybrid poplar clones (Populus x interamericana ‘Beaupré’, and Populus x euramericana ‘I-214’ and ‘MC’) in five localities of Castilla y León and Aragón (north and northeastern Spain, respectively) in summer 2002, 2014 and 2015. Affected trees were from nine to twenty six years old and disease incidence was up to 30% in some poplar stands. The bark of symptomatic trees was vertically cracked and copious white frothy fluid and creamy slime was observed. Some severely affected trees even died after few years. Isolations from exudates on King’s B medium yielded colonies light cream coloured, round, slightly convex and not fluorescent under UV light. A selection of ten purified isolates was further characterized and compared to the reference strain DSM25466T of Lonsdalea quercina subsp. populi (Tóth et al. 2013). All bacterial isolates were Gram-negative, facultative anaerobic, produced levan positive colonies and were esculin hydrolysis positive, but negative for oxidase, urease and tobacco hypersensitivity. Results in API 20E tests, incubated at 25ºC and 37ºC, showed that biochemical characteristics of the studied strains were consistent with those described for L. quercina subsp. populi. PCR amplification using specific primers for L. quercina LqfF/LqfR and LqgF/LqgR (Shang et al. 2015) resulted in the expected 382 and 286-bp amplicons, respectively. Partial 16S rDNA sequencing was used for identification of strains after amplification (Martinez-Murcia et al. 1992). Sequences were aligned and compared with those available in the GenBank database for species of the genera Lonsdalea and Brenneria and other phylogenetically related species. The program MEGA version 6.06 (Tamura et al. 2013) was used to construct a dendrogram using the maximum-likelihood method based on p-distance or the Tamura-Nei models. Results of 16S rDNA sequencing showed 99.8% to 100% sequence identity to the sequence of the strain DSM25466T of L quercina subsp. populi obtained in this work, or NY011 and NY041 from the database. All sequences obtained were submitted to GenBank under Accession Nos. KU531470 to KU531480. Pathogenicity tests were carried out on excised segments of poplar stems (P. x euramericana ‘I-214’) inoculated with bacterial suspensions (107 CFU/ml) (Li et al. 2014). Three stem segments were inoculated per bacterial isolate and after 4-5-days incubation at 28oC typical symptoms observed in the field were reproduced in 100% of the inoculated stems, whereas no symptoms were observed on negative controls. Similar bacteria were re-isolated from lesions of inoculated stems and resulting colonies were confirmed by biochemical tests and PCR. The recently described subspecies L. quercina susbsp. populi had been previously reported in Hungary (Tóth et al. 2013) and China (Li et al. 2014). To our knowledge, this is the first report of this bacterium causing bark canker disease of poplar in Spain and further surveys will help to asses its precise distribution. The disease could have a potential significant economic impact on susceptible poplar clones.Lonsdalea quercinaPublishe
La construcción de la Hacienda hispánica en el largo siglo XVIII: una investigación en curso
Dossier monographiqueInternational audienc