Maßnahmen gegen Virosen in der ökologischen Aquakultur

Im Projekt sollten verschiedene Strategien der Desinfektion von Teichböden untersucht werden, die nach einem Ausbruch der Krankheiten Virale Hämorrhagische Septikämie (VHS) und Koi Herpesvirus-Infektion (KHV-I) die verantwortlichen Viren KHV und VHSV zuverlässig inaktivieren. Besonderes Augenmerk sollte auf an Sedimenten gebundenes Virus gelegt werden, da vermutet wird, dass Sedimente als Reservoir für Viren dienen können. Um dieses Ziel zu erreichen, mussten zuerst ausreichende Viruskonzentrationen hergestellt werden, um die Desinfektionsversuche durchführen und adäquat dokumentieren zu können. Da bis zu diesem Zeitpunkt, im Fall des KHV, keine so hohen Titer gezeigt wer-den konnten, stellte die Verbesserung der in vitro KHV Replikation eine Grundvoraussetzung dar. Mittels verfahrenstechnischer Optimierung des Virus-Wirt-Systems konnte der Titer des KHV weit über die benötigte Infektiosität auf 1 x 108 plaqueforming units (PFU) per mL erhöht werden, das Inaktivierungsversuche für beide Viren ermöglichte. Die zunächst in der Suspension bestimmte minimale Konzentrationen von Branntkalk und Peressigsäure, die zu einer vollständigen Inaktivierung der beiden Viren führte, wurden respektive als 10 mmol/L und 0,1 vol.-% identifiziert. Eine Änderung des pH-Werts der Lösung auf unter 4,5 oder über 12 ist ebenso effektiv. Untersuchungen von 87 Teichböden zeigen eine Bandbreite des pH-Wertes des Bodens von 4,8 – 7,8 auf. Auf sehr sauren Teichböden ist daher keine Desinfektion mehr erforderlich bzw. ist die Desinfektion mittels Peressigsäure anstelle des Einsatzes von Branntkalk zu erwägen Zusätzlich wurde eine Protease (Neutrase®) zur Virusdesinfektion getestet und die benötigte Konzentration als 8 U/L ermittelt. Einflüsse der Temperatur auf die Stabilität decken sich mit Literaturanga-ben, wonach das VHSV ab 28°C innerhalb 24 Stunden und das KHV ab 35°C inaktiviert werden. Schließlich konnten diese Desinfektionsmethoden auch mit adsorbierten Viren bestätigt werden. Die hier ermittelten Viren-Stabilitätsdaten deuten darauf hin, dass eine Kombination aus allen natürlichen Faktoren, die in Teichen nach der Entfernung des erkrankten Fischbesatzes und dem Ablassen vorhanden sind (pH-Wert, Temperaturänderungen, Proteasen pro-duzierende Mikroflora), zur Inaktivierung der Viruspartikel ausreichen sollten. Da beide Viren gegenüber Gefrierzyklen stabil sind und alle Inaktivierungsprozesse bei niedrigen Temperaturen langsamer erfolgen, wird nach einem Infektionsausbruch das zeitweise Trockenlegen eines Teiches bei höheren Temperaturen empfohlen

Understanding the meaning of awareness in Research Networks

Reinhardt, W., Mletzko, C., Sloep, P. B., & Drachsler, H. (2012). Understanding the meaning of awareness in Research Networks. In A. Moore, V. Pammer, L. Pannese, M. Prilla, K. Rajagopal, W. Reinhardt, Th. D. Ullman, & Ch. Voigt (Eds.), Proceedings of the 2nd Workshop on Awareness and Reflection in Technology Enhanced Learning. In conjunction with the 7th European Conference on Technology Enhanced Learning: 21st Century Learning for 21st Century Skills (ARTEL/EC-TEL 2012) (pp. 13-30). September, 18, 2012, Saarbrücken, Germany. Available online at http://ceur-ws.org/Vol-931/ . [Please see also http://hdl.handle.net/1820/4729]underpinning and description of a tool that helps researchers become aware of their research context and reflect upon i

Towards a Security Architecture for Vehicular Ad Hoc Networks

Vehicular ad hoc networks (VANETs) have the potential to increase road safety and comfort. Especially because of the road safety functions, there is a strong demand for security in VANETs. After defining three application categories the paper outlines main security and privacy requirements in VANETs. Next, a security architecture for VANETs (SAV) is proposed that strives to satisfy the requirements. To find mechanisms applicable in the architecture a survey of existing mechanisms is given

Understanding the meaning of awareness in Research Networks

underpinning and description of a tool that helps researchers become aware of their research context and reflect upon i

Individualized mould-based high-dose-rate brachytherapy for perinasal skin tumors: technique evaluation from a dosimetric point of view

Purpose: Dosimetric treatment planning evaluations concerning patient-adapted moulds for iridium-192 highdose-rate brachytherapy are presented in this report. Material and methods: Six patients with perinasal skin tumors were treated with individual moulds made of biocompatible epithetic materials with embedded plastic applicators. Treatment plans were optimized with regard to clinical requirements, and dose was calculated using standard water-based TG-43 formalism. In addition, retrospective material-dependent collapsed cone calculations according to TG-186 protocol were evaluated to quantify the limitations of TG-43 protocol for this superficial brachytherapy technique. Results: The dose-volume parameters D90, V100, and V150 of the planning target volumes (PTVs) for TG-43 dose calculations yielded 92.2% to 102.5%, 75.1% to 93.1%, and 7.4% to 41.7% of the prescribed dose, respectively. The maximum overall dose to the ipsilateral eyeball as the most affected organ at risk (OAR) varied between 8.9 and 36.4 Gy. TG-186 calculations with Hounsfield unit-based density allocation resulted in down by –6.4%, –16.7%, and –30.0% lower average D90, V100, and V150 of the PTVs, with respect to the TG-43 data. The corresponding calculated OAR doses were also lower. The model-based TG-186 dose calculations have considered reduced backscattering due to environmental air as well as the dose-to-medium influenced by the mould materials and tissue composition. The median PTV dose was robust within 0.5% for simulated variations of mould material densities in the range of 1.0 g/cm³ to 1.26 g/cm³ up to 7 mm total mould thickness. Conclusions: HDR contact BT with individual moulds is a safe modality for routine treatment of perinasal skin tumors. The technique provides good target coverage and OARs’ protection, while being robust against small variances in mould material density. Model-based dose calculations (TG-186) should complement TG-43 dose calculations for verification purpose and quality improvement

Virucidal effects of various agents—including protease—against koi herpesvirus and viral haemorrhagic septicaemia virus

In a search for alternative, environmentally friendly and effective disinfecting agents, a commercially available protease—Neutrase®—was tested in this work for inactivation of koi herpesvirus (KHV) and of viral haemorrhagic septicaemia virus (VHSV). For comparison, the stability of these viral pathogens in similar configurations at various pH values and concentrations of peracetic acid or quicklime, typically used for disinfection, was tested. Therefore, virus suspensions were incubated with various concentrations of different agents for 24 hr and the titre of the remaining infectious particles was determined by virus titration. Furthermore, the treatment of both viruses, with the agents at concentrations that were previously appointed as effective, was also examined in the presence of solid material (quartz sand). All procedures investigated in this study, including the protease treatment, were able to reduce the titre of KHV and VHSV below the detection limit of the titration. Although further studies are necessary, this is the first report of the application of a protease for the inactivation of the selected fish pathogens, demonstrating the great potential of the latter for disinfection

Time-dependent effects of dexamethasone plasma concentrations on glucocorticoid receptor challenge tests

•Plasma dexamethasone concentrations were measured in depressed patients of two independent cohorts using mass-spectrometry.•Dex concentrations substantially influenced the readouts of the DST and dex-CRH test with an explained variance up to 41%.•A case/control effect in the dex-CRH test was only apparent when controlling for dexamethasone concentrations.•Dex concentrations at baseline and after treatment were highly correlated independent of treatment type and response status.•Gene expression or cortisol concentrations measured 3hours after dex ingestion were not influenced by dex concentrations.•The incorporation of dex concentrations improves the assessment of endocrine dysfunction in depression. Glucocorticoid challenge tests such as the dexamethasone suppression test (DST) and the combined dexamethasone/corticotropin-releasing hormone (dex-CRH) test are considered to be able to sensitively measure hypothalamic-pituitary-adrenal (HPA) axis activity in stress-related psychiatric and endocrine disorders. We used mass-spectrometry to assess the relationship of plasma dexamethasone concentrations and the outcome of these tests in two independent cohorts. Dexamethasone concentrations were measured after oral ingestion of 1.5mg dexamethasone in two cohorts that underwent a standard (dexamethasone at 23:00h) as well as modified (18:00h) DST and dex-CRH test. The first study population was a case/control cohort of 105 depressed patients and 133 controls in which peripheral blood mRNA expression was also measured. The second was a cohort of 261 depressed patients that underwent a standard dex-CRH test at baseline and after 12 weeks’ treatment with cognitive-behavioral therapy or antidepressants. Dexamethasone concentrations explained significant proportions of the variance in the DST in both the first (24.6%) and the second (5.2%) cohort. Dexamethasone concentrations explained a higher proportion of the variance in the dex-CRH test readouts, with 41.9% of the cortisol area under the curve (AUC) in the first sample and 24.7% in the second sample. In contrast to these strong effects at later time points, dexamethasone concentrations did not impact cortisol or ACTH concentrations or mRNA expression 3hours after ingestion. In the second sample, dexamethasone concentrations at baseline and week 12 were highly correlated, independent of treatment type and response status. Importantly, a case/control effect in the Dex-CRH test was only apparent when controlling for dexamethasone concentrations. Our results suggest that the incorporation of plasma dexamethasone concentration or measures of earlier endocrine read-outs may help to improve the assessment of endocrine dysfunction in depression