227 research outputs found
Vorrichtung zur Analyse der chemischen Zusammensetzung eines Gewässerbodens
Verfahren zur Analyse der chemischen Zusammensetzung eines Gewässerbodens umfassend folgende Schritte a. Bereitstellen einer
Vorrichtung umfassend eine Eindringsonde umfassend ein Messfenster mit einer Scheibe und Mittel zur Durchführung eines Röntgenfluoreszenz-
Verfahrens, welche über die Verbindungsvorrichtung mit einem Wasserfahrzeug verbunden ist, wobei die Eindringsonde in einer Wassertiefe bis
zu 6000 m vorliegt, b. Initialisierung eines schwerkraftbedingten Falls der Vorrichtung, c. zumindest teilweises Eindringen der Eindringsonde in
den Gewässerboden, in eine Tiefe von bis zu 18 m, bevorzugt in eine Tiefe von bis zu 12 m, d. Herausziehen der der Eindringsonde aus dem
Gewässerboden, mit einer bevorzugten Geschwindigkeit von 0,1 m/s, e. Durchführung eines Röntgenfluoreszenz-Verfahrens während des gesamten
Herausziehens, wobei in der Eindringsonde erzeugte Röntgenstrahlung durch das Messfenster abgestrahlt wird und im Gewässerboden generierte
Fluoreszenzstrahlung durch das Messfenster einfällt und detektiert wird, g. Verbleiben der Vorrichtung in einem gewässerbodennahen Arbeitsbereich
von bevorzugt 10 m über dem Gewässerboden
Superdeep Tests and Experiments at 9.1 km and 4 km
The Continental Deep Drilling Program of Germany (in German: Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland, abbreviated as KTB) was a scientific drilling project near the town of Windischeschenbach, Bavaria. The KTB Depth Laboratory comprises two 9.1 km and 4 km deep, water-filled boreholes in crystalline basement rocks just 200 meters apart from each other. Available equipment such as cables, winches, geophysical borehole tools as well as workshops and office infrastructure allows for in-situ tests and experiments at different pressure and temperature conditions. The two stable wells are large-diameter steel-cased and have been geophysically monitored in detail since 1996
Mismatch Negativity: Translating the Potential
The mismatch negativity (MMN) component of the auditory event-related potential has become a valuable tool in cognitive neuroscience. Its reduced size in persons with schizophrenia is of unknown origin but theories proposed include links to problems in experience-dependent plasticity reliant on N-methyl-d-aspartate glutamate receptors. In this review we address the utility of this tool in revealing the nature and time course of problems in perceptual inference in this illness together with its potential for use in translational research testing animal models of schizophrenia-related phenotypes. Specifically, we review the reasons for interest in MMN in schizophrenia, issues pertaining to the measurement of MMN, its use as a vulnerability index for the development of schizophrenia, the pharmacological sensitivity of MMN and the progress in developing animal models of MMN. Within this process we highlight the challenges posed by knowledge gaps pertaining to the tool and the pharmacology of the underlying system
Gletscherschrammen auf dem Piesberg bei Osnabrück : mit 1 Tabelle
Auf dem Piesberg bei Osnabrück konnten Gletscherschrammen beobachtet werden. Sie verlaufen überwiegend von NNE nach SSW. Diese Richtung stimmt gut mit Einregelungsmessungen an Geschiebe-Längsachsen in dem die Schrammenfläche bedeckenden Geschiebelehm überein. Gletscherschrammen und Geschiebelehm haben saalezeitliches Alter (Drenthe-Stadium)
Presence and Diversity of Different Enteric Viruses in Wild Norway Rats (Rattus norvegicus)
Abstract:
Rodents are common reservoirs for numerous zoonotic pathogens, but knowledge about
diversity of pathogens in rodents is still limited. Here, we investigated the occurrence and genetic
diversity of enteric viruses in 51 Norway rats collected in three different countries in Europe. RNA of
at least one virus was detected in the intestine of 49 of 51 animals. Astrovirus RNA was detected
in 46 animals, mostly of rat astroviruses. Human astrovirus (HAstV-8) RNA was detected in one,
rotavirus group A (RVA) RNA was identified in eleven animals. One RVA RNA could be typed as
rat G3 type. Rat hepatitis E virus (HEV) RNA was detected in five animals. Two entire genome
sequences of ratHEV were determined. Human norovirus RNA was detected in four animals
with the genotypes GI.P4-GI.4, GII.P33-GII.1, and GII.P21. In one animal, a replication competent
coxsackievirus A20 strain was detected. Additionally, RNA of an enterovirus species A strain was
detected in the same animal, albeit in a different tissue. The results show a high detection rate and
diversity of enteric viruses in Norway rats in Europe and indicate their significance as vectors for
zoonotic transmission of enteric viruses. The detailed role of Norway rats and transmission pathways
of enteric viruses needs to be investigated in further studies.Peer Reviewe
Increased Heat Resilience of Intraspecific Outbred Compared to Inbred Lineages in the Kelp Laminaria digitata: Physiology and Transcriptomics
Marine forests and kelps as their foundation species are threatened by ocean warming especially at the warm distributional edges. Previously identified genetic divergence and ecotypic differentiation within kelp species may allow to produce more resilient lineages by intraspecific outbreeding among populations. In a mechanistic investigation of heat stress, heterosis (hybrid vigour), and underlying gene expression patterns, we assessed the thermal performance of inbred (selfings) and outbred (reciprocal crosses) sporophytes of the N-Atlantic kelp Laminaria digitata among clonal isolates from two divergent populations; one from the temperate North Sea (Helgoland) and one from the Arctic (Spitsbergen). First, we investigated the upper thermal tolerance of microscopic sporophytes in a 14-day experiment applying sublethal to lethal 20–23°C. The upper survival temperature of microscopic sporophytes was lower for the inbred Arctic selfing (21°C) than for the temperate selfing and the reciprocal crosses (22°C). Only in the temperate selfing, 4.5% of sporophytes survived 23°C. We then subjected 4–7 cm long sporophytes to a control temperature (10°C), moderate (19°C) and sublethal to lethal heat stress (20.5°C) for 18 days to assess gene expression in addition to physiological parameters. Growth and optimum quantum yield decreased similarly in the reciprocal crosses and the temperate selfing at 19 and 20.5°C, while inbred Arctic sporophytes died within seven days at both 19 and 20.5°C. In response to 20.5°C, 252 genes were constitutively regulated across all surviving lineages, which we use to describe metabolic regulation patterns in response to heat stress in kelp. At sublethal 20.5°C, ca. 150 genes were differentially expressed by either crossed lineage in comparison to the temperate selfing, indicating that they maintained a growth response similar to the temperate selfing with differential metabolic regulation during sublethal heat stress. Subtle differences in physiology and the differential expression of nine genes between the reciprocal crosses at 20.5°C indicate that female and male gametophytes may contribute differently to offspring traits. We consider potential inbreeding depression in the Spitsbergen selfing and quantify the better performance of both crosses using heterosis-related parameters. We discuss the potential and risks of outbreeding to produce more resilient crops for mariculture and marine forest restoration
Is geographical variation driving the transcriptomic responses to multiple stressors in the kelp Saccharina latissima
Background: Kelps (Laminariales, Phaeophyceae) are brown macroalgae of utmost ecological, and increasingly
economic, importance on temperate to polar rocky shores. Omics approaches in brown algae are still scarce and
knowledge of their acclimation mechanisms to the changing conditions experienced in coastal environments can
benefit from the application of RNA-sequencing.
Despite evidence of ecotypic differentiation, transcriptomic responses from distinct geographical locations have, to
our knowledge, never been studied in the sugar kelp Saccharina latissima so far.
Results: In this study we investigated gene expression responses using RNA-sequencing of S. latissima from
environments with contrasting temperature and salinity conditions – Roscoff, in temperate eastern Atlantic, and
Spitsbergen in the Arctic. Juvenile sporophytes derived from uniparental stock cultures from both locations were
pre-cultivated at 8 °C and SA 30. Sporophytes acclimated to 0 °C, 8 °C and 15 °C were exposed to a low salinity
treatment (SA 20) for 24 h. Hyposalinity had a greater impact at the transcriptomic level than the temperature alone,
and its effects were modulated by temperature. Namely, photosynthesis and pigment synthesis were extensively
repressed by low salinity at low temperatures. Although some responses were shared among sporophytes from the
different sites, marked differences were revealed by principal component analysis, differential expression and GO
enrichment. The interaction between low temperature and low salinity drove the largest changes in gene
expression in sporophytes from Roscoff while specimens from Spitsbergen required more metabolic adjustment at
higher temperatures. Moreover, genes related to cell wall adjustment were differentially expressed between
Spitsbergen and Roscoff control samples.
Conclusions: Our study reveals interactive effects of temperature and salinity on transcriptomic profiles in S.
latissima. Moreover, our data suggest that under identical culture conditions sporophytes from different locations
diverge in their transcriptomic responses. This is probably connected to variations in temperature and salinity in
their respective environment of origin. The current transcriptomic results support the plastic response pattern in
sugar kelp which is a species with several reported ecotypes. Our data provide the baseline for a better
understanding of the underlying processes of physiological plasticity and may help in the future to identify strains
adapted to specific environments and its genetic control
A Semiquantitative Non-invasive Measurement of PcomA Patency in C57BL/6 Mice Explains Variance in Ischemic Brain Damage in Filament MCAo
Numerous studies on experimental ischemic stroke use the filament middle cerebral artery occlusion (fMCAo) model in C57BL/6 mice, but lesion sizes in this strain are highly variable. A known contributor is variation in the posterior communicating artery (PcomA) patency. We therefore aimed to provide a semiquantitative non-invasivein vivomethod to routinely assess PcomA patency. We included 43 male C57BL/6 mice from four independent studies using a transient 45 min fMCAo model. Edema-corrected lesion sizes were measured by magnetic resonance (MR) imaging 24 h after reperfusion. Time-of-flight MR angiography was performed 7 days before and 24 h after fMCAo. Scores of PcomA size measured 24 h after, but not scores measured 7 days before fMCAo were negatively correlated with lesion size. Variability in PcomA patency explained 30% of the variance in our cohort (p< 0.0001, coefficient of determinationr(2)= 0.3). In a simulation using parameters typical for experimental stroke research, the power to detect a true effect ofd= 1 between two groups increased by 15% when an according covariate was included in the statistical model. We have demonstrated thatin vivomeasurement of PcomA size is feasible and can lead to increased accuracy in assessing the effect of treatments
Refining Humane Endpoints in Mouse Models of Disease by Systematic Review and Machine Learning-Based Endpoint Definition
Ideally, humane endpoints allow for early termination of experiments by minimizing an animal’s discomfort, distress and pain, while ensuring that scientific objectives are reached. Yet, lack of commonly agreed methodology and heterogeneity of cut-off values published in the literature remain a challenge to the accurate determination and application of humane endpoints.
With the aim to synthesize and appraise existing humane endpoint definitions for commonly used physiological parameters, we conducted a systematic review of mouse studies of acute and chronic disease models, which used body weight, temperature and/or sickness scores for endpoint definition. In the second part of the study, we used previously published and unpublished data on weight, temperature and sickness scores from mouse models of sepsis and stroke and applied machine learning algorithms to assess the usefulness of this method for parameter selection and endpoint definition across models. Studies were searched for in two electronic databases (MEDLINE/Pubmed and Embase). Out of 110 retrieved full-text manuscripts, 34 studies were included. We found large intra- and inter-model variance in humane endpoint determination and application due to varying animal models, lack of standardized experimental protocols and heterogeneity of performance metrics (part 1).
Machine learning models trained with physiological data and sickness severity score or modified DeSimoni neuroscore identified animals with a high risk of death at an early time point in both mouse models of stroke (male: 93.2% at 72h post-treatment; female: 93.0% at 48h post-treatment) and sepsis (96.2% at 24h post-treatment), thus demonstrating generalizability in endpoint determination across models (part 2)
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