Telemetrische Untersuchungen zur Verbreitung, zum Tauchverhalten und zur Tauchphysiologie von Seehunden (Phoca vitulina vitulina) des Schleswig-Holsteinischen Wattenmeeres

In der vorliegenden Studie ist das herbst-winterliche Tauchverhalten von Seehunden des Schleswig-Holsteinischen Wattenmeeres mit Hilfe von Satellitensendern und Fahrtenschreibern telemetrisch untersucht worden. Die Tiere nutzten in diesem Zeitraum das Wattenmeer primär als Ruheraum. Beutesuche und Beutejagd finden fast ausschließlich in der vorgelagerten Nordsee statt. Länge und Gestaltung der Beutezüge unterschieden sich deutlich von den bisher für Seehunde beschriebenen Beutezügen. Sie hatten durchschnittliche Dauern von zwischen 12 und 70 Stunden, mit einem Maximum von 112 Stunden. Die dabei zurückgelegten Wegstrecken reichten bis zu 100 km linearer Distanz zwischen dem Hauptruheplatz im Wattenmeer und den Jagdorten auf See. Die Seehunde waren in ihren durchschnittlichen Tauchtiefen von 20 - 30 m topographisch limitiert. Fast alle Tauchgänge innerhalb der Beutezüge waren benthisch ausgerichtet. Über 85% ihrer Zeit auf See verbrachten die Robben getaucht. Die Tiere sind dabei jedoch nicht an ihre tauchphysiologischen Leistungsgrenzen gestoßen zu sein. Die für alle marinen Säuger limitierende "Aerobe Tauchgrenze" (ATG) wurde offensichtlich in keinem Fall erreicht bzw. überschritten. Das Ruheverhalten der Tiere korrelierte weder mit den Gezeiten noch mit klimatischen Faktoren. Ergänzend wurden mit Hilfe eines Seehundmodelles verschiedene Telemetriegeräte in einem Windkanal auf die durch sie induzierte Zunahme des Strömungswiderstandes untersucht. Dadurch sollten mögliche energetische bzw. verhaltensbiologische Folgen telemetrischer Studien an Robben erkannt und quantifiziert werden

Aspartoacylase-LacZ Knockin Mice: An Engineered Model of Canavan Disease

Canavan Disease (CD) is a recessive leukodystrophy caused by loss of function mutations in the gene encoding aspartoacylase (ASPA), an oligodendrocyte-enriched enzyme that hydrolyses N-acetylaspartate (NAA) to acetate and aspartate. The neurological phenotypes of different rodent models of CD vary considerably. Here we report on a novel targeted aspa mouse mutant expressing the bacterial β-Galactosidase (lacZ) gene under the control of the aspa regulatory elements. X-Gal staining in known ASPA expression domains confirms the integrity of the modified locus in heterozygous aspa lacZ-knockin (aspalacZ/+) mice. In addition, abundant ASPA expression was detected in Schwann cells. Homozygous (aspalacZ/lacZ) mutants are ASPA-deficient, show CD-like histopathology and moderate neurological impairment with behavioural deficits that are more pronounced in aspalacZ/lacZ males than females. Non-invasive ultrahigh field proton magnetic resonance spectroscopy revealed increased levels of NAA, myo-inositol and taurine in the aspalacZ/lacZ brain. Spongy degeneration was prominent in hippocampus, thalamus, brain stem, and cerebellum, whereas white matter of optic nerve and corpus callosum was spared. Intracellular vacuolisation in astrocytes coincides with axonal swellings in cerebellum and brain stem of aspalacZ/lacZ mutants indicating that astroglia may act as an osmolyte buffer in the aspa-deficient CNS. In summary, the aspalacZ mouse is an accurate model of CD and an important tool to identify novel aspects of its complex pathology

Retrospective analysis of factors associated with outcome in veno-venous extra-corporeal membrane oxygenation

Abstract Background The outcome of Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) in acute respiratory failure may be influenced by patient-related factors, center expertise and modalities of mechanical ventilation (MV) during ECMO. We determined, in a medium-size ECMO center in Switzerland, possible factors associated with mortality during VV-ECMO for acute respiratory failure of various etiologies. Methods We retrospectively analyzed all patients treated with VV-ECMO in our University Hospital from 2012 to 2019 (pre-COVID era). Demographic variables, severity scores, MV duration before ECMO, pre and on-ECMO arterial blood gases and respiratory variables were collected. The primary outcome was ICU mortality. Data were compared between survivors and non-survivors, and factors associated with mortality were assessed in univariate and multivariate analyses. Results Fifty-one patients (33 ARDS, 18 non-ARDS) were included. ICU survival was 49% (ARDS, 39%; non-ARDS 67%). In univariate analyses, a higher driving pressure (DP) at 24h and 48h on ECMO (whole population), longer MV duration before ECMO and higher DP at 24h on ECMO (ARDS patients), were associated with mortality. In multivariate analyses, ECMO indication, higher DP at 24h on ECMO and, in ARDS, longer MV duration before ECMO, were independently associated with mortality. Conclusions DP on ECMO and longer MV duration before ECMO (in ARDS) are major, and potentially modifiable, factors influencing outcome during VV-ECMO

Metal Free Photocatalytic Graphitic Carbon Nitride on p Type Chalcopyrite as a Composite Photocathode for Light Induced Hydrogen Evolution

Recently, it has been shown that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible light irradiation in the presence of a sacrificial donor. We present herein the preparation and characterization of graphitic carbon nitride g C3N4 films on p type semiconducting CuGaSe2 chalcopyrite thin film substrates by thermal condensation of a dicyandiamide precursor under inert gas conditions. Structural and surface morphological studies of the carbon nitride films suggest a high porosity of g C3N4 thin films consisting of a network of nanocrystallites. Photoelectrochemical investigations show light induced hydrogen evolution upon cathodic polarization for a wide range of proton concentrations in the aqueous electrolyte. Additionally, synchrotron radiation based photoelectron spectroscopy has been applied to study the surface near surface chemical composition of the utilized g C3N4 film photocathodes. For the first time, it has been shown that g C3N4 films coated on p type CuGaSe2 thin films can be successfully applied as new photoelectrochemical composite photocathodes for light induced hydrogen evolutio