Transfer of Navicula hochstetteri var. patagonica Frenguelli to the genus Cavinula (Cavinulaceae, Bacillariophyta) and lectotype designation

We give a detailed morphological description of the original material of N. hochstetteri var. patagonica and we propose to transfer this taxon to the genus Cavinula and raise it to species level as Cavinula patagonica below. A specimen from the original material of the Joaquín Frenguelli diatom collection is here designated as lectotype.Fil: Lameiro, Rubén Agustín. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; ArgentinaFil: Cefarelli, Adrián Oscar. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Vouilloud, Amelia Alejandra Beatriz. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentin

Influencia de los témpanos sobre la composición y abundancia fitoplanctónica en aguas abiertas antárticas

El presente trabajo de tesis doctoral, enmarcado dentro de un proyecto interdisciplinario más amplio, tiene como objetivo general analizar la influencia que los témpanos pueden ejercer sobre la composición y abundancia de la comunidad fitoplanctónica en aguas abiertas antárticas durante dos estaciones del año diferentes, con especial énfasis en el grupo de las diatomeas (Bacillariophyceae). Cabe resaltar la permanente intención de este trabajo de determinar y explicar las posibles relaciones existentes entre las diferentes variables analizadas, de manera que se puedan establecer relaciones causa-efecto entre las mismas. No obstante, tratándose de un tema u objeto de estudio casi desconocido para la ciencia, se reconoce en cierta parte, el carácter exploratorio de esta investigación. Los objetivos específicos de este estudio son: • Caracterizar taxonómicamente la flora diatomológica adherida a los flancos sumergidos de los témpanos, así como aquellos taxa más relevantes encontrados en aguas adyacentes. • Determinar y comparar la composición de la comunidad fitoplanctónica, con especial énfasis en las diatomeas, en cada sitio y estación anual de muestreo. • Analizar comparativamente la estructura de la comunidad fitoplanctónica en relación a la presencia-ausencia de témpanos, la distancia a los mismos y la época del año. • Determinar el efecto de los témpanos sobre las propiedades fisicoquímicas de la columna de agua, considerando el tamaño de los témpanos y la época del año. • Analizar comparativamente la estructura de la comunidad fitoplanctónica en relación a las propiedades físicas, químicas y biológicas imperantes en cada sitio de muestreo. • Establecer la importancia del hierro para el fitoplancton antártico a través de experiencias de cultivo, teniendo en cuenta el posible aporte de nutrientes por parte de los témpanos.Facultad de Ciencias Naturales y Muse

Thalassioneis signyensis (bacillariophyceae) from northwest weddell sea icebergs, an emendation of the generic description

We offer an emended description of the genus Thalassioneis based on new observations of the type species, T. signyensis Round, from material sampled in the northwest Weddell Sea. Specimens from algal communities attached to submerged flanks of several icebergs were collected with a remote-operated vehicle (ROV-Phantom DS 2). The analyses were carried out by LM and SEM. Fresh material and frustules without organic matter allowed us to observe details not included in the original description such as type and structure of colonies and chloroplasts. The frustule shows an asymmetry with respect to the location of the apical pore fields, one of them situated on the valvar face and the other one displaced toward the mantle; the former is involved in joining contiguous cells to form long chains. Furthermore, we present details on the ultrastructure of the cingulum that consists of three to four open copulae with one or more rows of poroids. A brief discussion on the habit and ecology of this taxon, which may be endemic to the northwest Weddell Sea, is also presented. A comparison with similar genera, such as Brandinia, Creania, Fossula, Fragilaria, Rimoneis, Synedropsis, and Ulnaria, is included with an evaluation of morphological characteristics useful to differentiate them.Fil: Ferrario, Martha Elba. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Cefarelli, Adrián Oscar. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Robison, Bruce. Monterey Bay Aquarium Research Institute; Estados UnidosFil: Vernet, María. University of California at San Diego; Estados Unido

Normothermic frozen elephant trunk: our experience and literature review

none6Background and Objective: The frozen elephant trunk (FET) technique has undoubtable advantages in treating complex and extensive disease of the aortic arch and the thoracic descending aorta. Despite several improvements in cardiopulmonary bypass conduction and surgical strategy, operative times and the institution of systemic circulatory arrest remain the main determinants of early mortality, cerebral/spinal cord injury and visceral organs dysfunction. We have conducted this review to highlight the recent technical advances in arch and FET surgery aiming at the reduction/avoidance of systemic circulatory arrest, and their impact on early outcomes. Methods: A literature search (from origin to January 2022), limited to publications in English, was performed on online platforms and database (PubMed, Google, ResearchGate). After a further review of associated or similar papers, we found 4 experiences, described by 11 peer-reviewed published papers, which focused on minimising or avoiding systemic circulatory arrest during total arch replacement plus stenting of the descending thoracic aorta. Key Content and Findings: Recent experiences reported the use of an antegrade endoaortic balloon, advanced and inflated into the stent graft, to provide an early systemic reperfusion soon after the deployment of the stented portion of the FET prosthesis and minimize the circulatory arrest time (down to a mean of 5 minutes), thus avoiding the need of moderate or deep hypothermia (mean systemic temperature 28-30 ???) while allowing a complete arch and FET repair. Our approach, based on off-pump retrograde vascular stent graft deployment in distal arch/descending thoracic aorta, and the use of a retrograde endoballoon, allows the repair of extensive aortic pathologies during uninterrupted normothermic cerebral and lower body perfusion. Conclusions: The use of endoballoon occlusion has emerged in recent years as a safe and effective strategy to allow distal perfusion during FET repair. This technique minimizes or avoids the detrimental effects of hypothermia and systemic circulatory arrest and significantly reduces the operative times.Malvindi, PG; Alfonsi, J; Berretta, P; Cefarelli, M; Gatta, E; Di Eusanio, MMalvindi, Pg; Alfonsi, J; Berretta, P; Cefarelli, M; Gatta, E; Di Eusanio,

Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: Morphology, distribution and abundance

Fragilariopsis species composition and abundance from the Argentine Sea and Antarctic waters were analyzed using light and electron microscopy. Twelve species (F. curta, F. cylindrus, F. kerguelensis, F. nana, F. obliquecostata, F. peragallii, F. pseudonana, F. rhombica, F. ritscheri, F. separanda, F. sublinearis and F. vanheurckii) are described and compared with samples from the Frenguelli Collection, Museo de La Plata, Argentina. F. peragallii was examined for the first time using electron microscopy, and F. pseudonana was recorded for the first time in Argentinean shelf waters. New information on the girdle view is included, except for the species F. curta, F. cylindrus and F. nana, for which information already existed. In the Argentine Sea, F. pseudonana was the most abundant Fragilariopsis species, and in Antarctic waters, F. curta was most abundant. Of the twelve species of Fragilariopsis documented, four occurred in the Argentine Sea, nine in the Drake Passage and twelve in the Weddell Sea. F. curta, F. kerguelensis, F. pseudonana and F. rhombica were present everywhere.Facultad de Ciencias Naturales y Muse

El microscopio electrónico de barrido

¿Sabías que el Microscopio Electrónico de Barrido (MEB) permite observar detalles de la topografía superficial de diversos especímenes en 3 dimensiones, aumentando hasta 300.000 veces su tamaño original. De esta forma, se pueden realizar análisis ultraestructurales de cualquier tipo de organismo animal o vegetal, minerales, fósiles, restos arqueológicos, etc., que resultan imperceptibles a simple vista. El Museo de la Plata cuenta con un Servicio de Microscopía Electrónica de Barrido que fue inaugurado el 3 de agosto de 1987. Gracias a un convenio de intercambio entre la Universidad Nacional de La Plata y la Prefectura de Tokushima-Japón, y a las gestiones realizadas por el destacado paleontólogo Dr. Rosendo Pascual, llegó el primer MEB.Sección: ¿Sabías que...?Fundación Museo La Plat

El microscopio electrónico de barrido

¿Sabías que el Microscopio Electrónico de Barrido (MEB) permite observar detalles de la topografía superficial de diversos especímenes en 3 dimensiones, aumentando hasta 300.000 veces su tamaño original. De esta forma, se pueden realizar análisis ultraestructurales de cualquier tipo de organismo animal o vegetal, minerales, fósiles, restos arqueológicos, etc., que resultan imperceptibles a simple vista. El Museo de la Plata cuenta con un Servicio de Microscopía Electrónica de Barrido que fue inaugurado el 3 de agosto de 1987. Gracias a un convenio de intercambio entre la Universidad Nacional de La Plata y la Prefectura de Tokushima-Japón, y a las gestiones realizadas por el destacado paleontólogo Dr. Rosendo Pascual, llegó el primer MEB.Sección: ¿Sabías que...?Fundación Museo La Plat

Diatoms (Bacillariophyceae) associated with free-drifting Antarctic icebergs: taxonomy and distribution

Free-drifting Antarctic icebergs can alter the phytoplankton in surrounding waters. In addition, diatom mats live attached to the submerged walls of the icebergs. In this study we describe a diverse diatom community associated with these mats and an atypical planktonic community in waters affected by icebergs. Samples were collected in the winter of 2008 and fall of 2009 from Antarctic icebergs and their adjacent waters, utilizing a remote operated vehicle and plankton nets, respectively, and subsequently analyzed using light and electron microscopy. Thalassioneis signyensis, dominant species growing on the icebergs’ flanks, provided substrate for other diatoms, mainly Synedropsis lata var. angustata, Synedropsis recta, Fragilaria cf. islandica var. adeliae, Attheya gaussii, Navicula cf. perminuta, Amphora sp. and Nitzschia spp. New morphological characteristics are given for S. lata var. angustata, S. recta and A. gaussii. We report also Biddulphia alternans and Coscinodiscus concinnus for the first time in Antarctic waters. Similar to sea ice algae, the term sympagic is used to describe the habitat of these diatom communities. A particular planktonic community is also found close to icebergs, including diatoms known to have a benthic, epiphytic, sympagic or freshwater habitat: Amphora sp., B. alternans, Cocconeis spp., Delphineis minutissima, Licmophora gracilis, Luticola cf. australomutica, Opephora sp., Pinnularia spp., Plagiogramma sp., Psammodictyon panduriforme var. minor, Pseudogomphonema kamtschaticum, Rhaphoneis amphiceros, S. recta and T. signyensis. Our results support the hypothesis that species associated with icebergs exchange freely with plankton, ice shelves and sea ice, suggesting that icebergs can act as physical agents to transport and distribute organisms in between these habitats.Facultad de Ciencias Naturales y MuseoConsejo Nacional de Investigaciones Científicas y Técnica

Extracorporeal Membrane Oxygenation Support as Treatment for Early Graft Failure After Heart Transplantation

Early graft failure (EGF) is a major risk factor for death after heart transplantation (Htx) accounting for >40% of deaths within 30 days postoperatively. According to the last International Society for Heart and Lung Transplantation (ISHLT) consensus statement, the graft dysfunction (GD) is to be classified into primary (PGD), in case of an unknown triggering factor or secondary (SGD) where there is a discernible cause such as acute rejection, pulmonary hypertension, or known surgical complications. The diagnosis of GD is to be made within 24 h after completion of Htx surgery and a severity scale for GD should include mild, moderate, or severe grades based on specified criteria. Mechanical circulatory support (MCS) for GD should be considered when medical management is not sufficient to support the newly transplanted graft. Currently, extra‐corporeal membrane oxygenation (ECMO) is widely accepted as treatment of severe EGF, given its easy and quick setup, the system versatility, the optimal end‐organ perfusion provided, and the possibility of both biventricular and lung assistance by usage of a low‐cost single pump