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Das Teilprojekt Landschafts- und Autökologie (LÖK) hat den Schwerpunkt auf die Erarbeitung einer e- Learning-Einheit zur Habitatmodellierung im allgemeinen und dem Verfahren der logistischen Regression im speziellen gelegt. In den sechs Lernmodulen der Lerneinheit werden alle für eine erfolgreiche Modellierung der Habitateignung erforderlichen Arbeitsschritte sequentiell behandelt. Die wesentlichen Schritte werden mit interaktiven Aufgaben vertieft, in welchen an entscheidenden Stellen WebGIS eingesetzt wird. Der räumliche Bezug wird in der Regel über WebGIS- Anwendungen zu einer virtuellen Landschaft hergestellt, die in das GIMOLUS-System integriert ist. Die erforderlichen Datensätze für die Analyse von Art-Habitat- Beziehungen werden bereitgestellt oder können interaktiv aus der virtuellen Landschaft erzeugt werden.
Internationale Freiwilligendienste (IFD) sind ein hochaktuelles wie auch umstrittenes Thema. Die Zahl der deutschen Jugendlichen, die an IFD-Programmen teilnehmen, ist in den vergangenen Jahren erheblich gestiegen und die Volunteer-Branche hat sich stark diversifiziert. Was die verschiedenen Formen staatlicher und privatwirtschaftlicher IFD eint, ist die explizite Abgrenzung vom Tourismus. Bei dieser Abgrenzung handelt es sich jedoch um eine Exklusion, die das Ausgeschlossene gerade nicht als irrelevant, sondern für den Kommunikationszusammenhang als überaus bedeutsam markiert.
Ziel dieses Buches ist es, aufzuzeigen wie Tourismus als ANDERES konstruiert und dies zur Selbstidentifikation der Freiwilligen genutzt wird. Unter Zuhilfenahme des Laclau/Mouffe’schen Theoriegebäudes werden die Selbst- und Fremdbilder von deutschsprachigen Teilnehmer(innen) verschiedener IFD-Programme in Ghana hinsichtlich ihrer Deutungsansprüche und Identifikationsmechanismen betrachtet. Der Fokus richtet sich dabei auf Prozesse der Grenzziehung, die das Sprechen der Freiwilligen in Bereiche des EIGNENEN und des ANDEREN unterteilen. Im Sinne einer dem cultural turn verpflichteten Neuen Kulturgeographie wird der Verwendung räumlicher Identitätsanker dabei besondere Aufmerksamkeit gewidmet.
In five studies, we evaluated the psychometric properties of a revised German version of the State Self-Esteem Scale (SSES; Heatherton & Polivy, 1991). In Study 1, the results of a confirmatory factor analysis on the original scale revealed poor model fit and poor construct validity in a student sample that resembled those in the literature; thus, a revised 15-item version was developed (i.e., the SSES-R) and thoroughly validated. Study 2 showed a valid three-factor structure (Performance, Social, and Appearance) and good internal consistency of the SSES-R. Correlations between subscales of trait and state SE empirically supported the scale's construct validity. Temporal stability and intrapersonal sensitivity of the scale to naturally occurring events were investigated in Study 3. Intrapersonat sensitivity of the scale to experimentally induced changes in state SE was uncovered in Study 4 via social feedback (acceptance vs. rejection) and performance feedback (positive vs. negative). In Study 5, the scale's interpersonal sensitivity was confirmed by comparing depressed and healthy individuals. Finally, the usefulness of the SSES-R was demonstrated by assessing SE instability as calculated from repeated measures of state SE.
Following stroke, neuronal death takes place both in the infarct region and in brain areas distal to the lesion site including the hippocampus. The hippocampus is critically involved in learning and memory processes and continuously generates new neurons. Dysregulation of adult neurogenesis may be associated with cognitive decline after a stroke lesion. In particular, proliferation of precursor cells and the formation of new neurons are increased after lesion. Within the first week, many new precursor cells die during development. How dying precursors are removed from the hippocampus and to what extent phagocytosis takes place after stroke is still not clear. Here, we evaluated the effect of a prefrontal stroke lesion on the phagocytic activity of microglia in the dentate gyrus (DG) of the hippocampus. Three-months-old C57BL/6J mice were injected once with the proliferation marker BrdU (250 mg/kg) 6 hr after a middle cerebral artery occlusion or sham surgery. The number of apoptotic cells and the phagocytic capacity of the microglia were evaluated by means of immunohistochemistry, confocal microscopy, and 3D-reconstructions. We found a transient but significant increase in the number of apoptotic cells in the DG early after stroke, associated with impaired removal by microglia. Interestingly, phagocytosis of newly generated precursor cells was not affected. Our study shows that a prefrontal stroke lesion affects phagocytosis of apoptotic cells in the DG, a region distal to the lesion core. Whether disturbed phagocytosis might contribute to inflammatory- and maladaptive processes including cognitive impairment following stroke needs to be further investigated.
The rooted zone of a soil, more precisely the rhizosphere, is a very dynamic system. Some of the key processes are water uptake and root respiration. We have developed a novel method for measuring the real-time distribution of water and oxygen concentration in the rhizosphere as a biogeochemical interface in soil. This enables understanding where and when roots are active in respect to root respiration and water uptake and how the soil responds to it.
We used glass containers (15 x 15 x 1 cm), which were filled with a quartz sand mixture. Sensor foils for fluorescence dye imaging of O-2 were installed on the inner side of the containers. A lupine plant was grown in each container for 2 weeks under controlled conditions. Then we took time series of fluorescence images for time-lapsed visualization of oxygen depletion caused by root respiration. Changing water content was mapped in parallel by non-invasive neutron radiography, which yields water content distributions in high spatial resolution. Also it can detect the root system of the lupine plants. By this combined imaging of the samples, a range of water contents and different oxygen concentration levels, both induced by root activities, could be assessed.
We monitored the dynamics of these vital parameters induced by roots during a period of several hours. We observed that for high water saturation, the oxygen concentration decreased in parts of the container. The accompanying neutron radiographies gave us the information that these locations are spatially correlated to roots. Therefore, it can be concluded that the observed oxygen deficits close to the roots result from root respiration and show up while re-aeration from atmosphere by gas phase transport is restricted by the high water saturation.
Our coupled imaging setup was able to monitor the spatial distribution and temporal dynamics of oxygen and water content in a night and day cycle. This reflects complex plant activities such as photosynthesis, transpiration, and metabolic activities impacting the root-soil interface. Our experimental setup provides the possibility to non-invasively visualize these parameters with high resolution. The particular oxygen imaging method as well as the combination with simultaneously mapping the water content by neutron radiography is a novelty.
The rhizosphere is a dynamic system strongly influenced by root activity. Roots modify the pH of their surrounding soil causing the soil pH to vary as a function of distance from root surface, location along root axes, and root maturity. Non-invasive imaging techniques provide the possibility to capture pH patterns around the roots as they develop.
We developed a novel fluorescence imaging set up and applied to the root system of two lupin (Lupinus albus L., Lupinus angustifolius L.) and one soft-rush (Juncus effusus L.) species. We grew plants in glass containers filled with soil and equipped with fluorescence sensor foils on the container side walls. We gained highly-resolved data on the spatial distribution of H+ around the roots by taking time-lapse images of the samples over the course of several days.
We showed how the soil pH in the vicinity of roots developed over time to different values from that of the original bulk soil. The soil pH in the immediate vicinity of the root surface varied greatly along the root length, with the most acidic point being at 0.56-3.36 mm behind the root tip. Indications were also found for temporal soil pH changes due to root maturity.
In conclusion, this study shows that this novel optical fluorescence imaging set up is a powerful tool for studying pH developments around roots in situ.
Der Klang der Erinnerung
(2021)
Präexistente Musik im Film
(2022)
Vom Weltuntergang mit Richard Wagners "Tristan und Isolde" über die Gesangsperformance einer zum Tode verurteilten Björk am Galgen bis hin zu Johann Sebastian Bachs Orgelmusik als Erklärungsmodell für Hypersexualität: So seltsam das Kino des Lars von Trier erscheinen mag, so vielfältige Möglichkeiten bietet es, über ein Musikphänomen nachzudenken, das einen Großteil der heutigen Kunst- und Unterhaltungswelt prägt.
In Lars von Triers Filmen erklingt hauptsächlich Musik, die es bereits vor den Filmen gab. Einerseits besitzt solche präexistente Musik ein ausgeprägtes Eigenleben, andererseits entsteht aus der filmischen Aneignung etwas Neues. Am Beispiel eines der einflussreichsten Regisseure der Gegenwart untersucht Pascal Rudolph, wie Filmschaffende Musik adaptieren und wie dadurch Bedeutungen und Wirkungen entstehen. Erstmals bietet das Buch auf Grundlage von unveröffentlichtem Produktionsmaterial und Insider-Interviews detaillierte Einblicke in die Arbeit bei Lars von Triers Filmprojekten im Besonderen, aber auch in die Arbeitsprozesse der filmmusikalischen Gestaltung im Allgemeinen. Der musikalischen Vielfalt in den Filmen wird die Studie durch ihren multiperspektivischen und transdisziplinären Ansatz gerecht. Die zehn Kapitel beleuchten das Zusammenwirken von Musik und Film auf diese Weise aus verschiedenen Blickwinkeln.
Präexistente Musik im Film
(2022)
Vom Weltuntergang mit Richard Wagners "Tristan und Isolde" über die Gesangsperformance einer zum Tode verurteilten Björk am Galgen bis hin zu Johann Sebastian Bachs Orgelmusik als Erklärungsmodell für Hypersexualität: So seltsam das Kino des Lars von Trier erscheinen mag, so vielfältige Möglichkeiten bietet es, über ein Musikphänomen nachzudenken, das einen Großteil der heutigen Kunst- und Unterhaltungswelt prägt.
In Lars von Triers Filmen erklingt hauptsächlich Musik, die es bereits vor den Filmen gab. Einerseits besitzt solche präexistente Musik ein ausgeprägtes Eigenleben, andererseits entsteht aus der filmischen Aneignung etwas Neues. Am Beispiel eines der einflussreichsten Regisseure der Gegenwart untersucht Pascal Rudolph, wie Filmschaffende Musik adaptieren und wie dadurch Bedeutungen und Wirkungen entstehen. Erstmals bietet das Buch auf Grundlage von unveröffentlichtem Produktionsmaterial und Insider-Interviews detaillierte Einblicke in die Arbeit bei Lars von Triers Filmprojekten im Besonderen, aber auch in die Arbeitsprozesse der filmmusikalischen Gestaltung im Allgemeinen. Der musikalischen Vielfalt in den Filmen wird die Studie durch ihren multiperspektivischen und transdisziplinären Ansatz gerecht. Die zehn Kapitel beleuchten das Zusammenwirken von Musik und Film auf diese Weise aus verschiedenen Blickwinkeln.
Brown und Van Kleeck (1989) haben postuliert, daß die Wahrnehmung von Verursachung interpersonaler Ereignisse vor allem durch zwei Faktoren determiniert wird: Zum einen geben die zur Beschreibung von interpersonalen Handlungen und Zuständen verwendeten Verben implizit Auskunft darüber, welcher der Interaktionspartner das fragliche Ereignis verursacht hat. Zum anderen gehorchen die Erklärungen interpersonaler Ereignisse dem Prinzip der Balance. So werden positive Ereignisse nahezu ausschließlich durch positive Ursachen, negative Ereignisse durch negative Ursachen erklärt. Das Zusammenspiel beider Mechanismen hat darüber hinaus vielfältige weitere Konsequenzen für die Erklärung interpersonaler Ereignisse: 1. Bei balancierten Triaden werden die beschriebenen Ereignisse demjenigen Interaktionspartner zugeschrieben, der qua Verbkausalität als kausal verantwortlich anzusehen ist. 2. Bei unbalancierten Triaden hingegen wird das Ereignis ganz überwiegend demjenigen Interaktionspartner zugeschrieben, welcher der impliziten Verbkausalität zufolge als kausal weniger bedeutsamer Interaktionspartner anzusehen ist. Im vorliegenden Experiment wird geprüft, ob eine solche Attributionsumkehr für unbalancierte interpersonale Ereignisse mit korrespondierenden Veränderungen der Wahrnehmung von kausal relevanten Informationen einhergeht. Die vorliegenden Ergebnisse zeigen, daß in der Tat die Wahrnehmung von Konsensus und Distinktheit - Kovariationsinformationen sensu Kelley (1972) - im Falle balancierter versus unbalancierter Triaden jeweils genau entgegengesetzt sind. Diese Ergebnisse sprechen dafür, daß diese klassischen attributionstheoretischen Variablen geeignete Kandidaten zur Erklärung der Attributionsmuster für balancierte und unbalancierte interpersonale Ereignisse darstellen, welche die komplexen Befunde zum Zusammenspiel von Verbkausalität und Balance in sparsamer Weise erklären.
In soils and sediments there is a strong coupling between local biogeochemical processes and the distribution of water, electron acceptors, acids and nutrients. Both sides are closely related and affect each other from small scale to larger scales. Soil structures such as aggregates, roots, layers or macropores enhance the patchiness of these distributions. At the same time it is difficult to access the spatial distribution and temporal dynamics of these parameter. Noninvasive imaging techniques with high spatial and temporal resolution overcome these limitations. And new non-invasive techniques are needed to study the dynamic interaction of plant roots with the surrounding soil, but also the complex physical and chemical processes in structured soils. In this study we developed an efficient non-destructive in-situ method to determine biogeochemical parameters relevant to plant roots growing in soil. This is a quantitative fluorescence imaging method suitable for visualizing the spatial and temporal pH changes around roots. We adapted the fluorescence imaging set-up and coupled it with neutron radiography to study simultaneously root growth, oxygen depletion by respiration activity and root water uptake. The combined set up was subsequently applied to a structured soil system to map the patchy structure of oxic and anoxic zones induced by a chemical oxygen consumption reaction for spatially varying water contents. Moreover, results from a similar fluorescence imaging technique for nitrate detection were complemented by a numerical modeling study where we used imaging data, aiming to simulate biodegradation under anaerobic, nitrate reducing conditions.
Purpose
Root growth, respiration, water uptake as well as root exudation induce biogeochemical patterns in the rhizosphere that can change dynamically over time. Our aim is to develop a method that provides complementary information on 3D root system architecture and biogeochemical gradients around the roots needed for the quantitative description of rhizosphere processes.
Methods
We captured for the first time the root system architecture of maize plants grown in rectangular rhizotrons in 3D using neutron computed laminography (NCL). Simultaneously, we measured pH and oxygen concentration using fluorescent optodes and the 2D soil water distribution by means of neutron radiography. We co-registered the 3D laminography data with the 2D oxygen and pH maps to analyze the sensor signal as a function of the distance between the roots and the optode.
Results
The 3D root system architecture was successfully segmented from the laminographic data. We found that exudation of roots in up to 2 mm distance to the pH optode induced patterns of local acidification or alkalization. Over time, oxygen gradients in the rhizosphere emerged for roots up to a distance of 7.5 mm.
Conclusion
Neutron computed laminography allows for a three-dimensional investigation of root systems grown in laterally extended rhizotrons as the ones designed for 2D optode imaging studies. The 3D information on root position within the rhizotrons derived by NCL explained measured 2D oxygen and pH distribution. The presented new combination of 3D and 2D imaging methods facilitates systematical investigations of a wide range of dynamic processes in the rhizosphere.
Non-invasive imaging techniques to study O-2 micro-patterns around pesticide treated lupine roots
(2015)
The soil root interface is a highly heterogeneous system, e.g. in terms of O-2 and pH distribution. The destructive character of conventional methods disturbs the natural conditions of those biogeochemical gradients. Therefore, experiments aiming to control these influences and study pesticide kinetics under given O-2 and pH conditions suffer from a large uncertainty of the "real" O-2/pH at a certain position. Our approach with two different imaging techniques will examine the soil-root interface as well as the dissipation of the applied pesticide at a high spatial resolution.
The obtained outcomes show directly that the pH has an influence on enantioselective dissipation of the acetanilide fungicide metalaxyl. In areas with high pH from an applied racemic mixture, the R-enantiomer dissipates faster than the S-enantiomer. Moreover, we found significantly reduced oxygen values in the bulk soil and vicinity of metalaxyl treated roots compared to control plant roots. The combination of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) and fluorescence imaging indicated the oxygen-dependent behavior of metalaxyl at the root surface.
The results presented here underline the great potential of combining different imaging methods to examine the soil-root interfaces as well as the dissipation of organic pollutants in small soil compartments. (C) 2014 Elsevier B.V. All rights reserved.
Rhizosphere processes are highly dynamic in time and space and strongly depend on each other. Key factors influencing pH changes in the rhizosphere are root exudation, respiration, and nutrient supply, which are influenced by soil water content levels. In this study, we measured the real-time distribution of soil water, pH changes, and oxygen distribution in the rhizosphere of young maize plants using a recently developed imaging approach. Neutron radiography was used to capture the root system and soil water distribution, while fluorescence imaging was employed to map soil pH and soil oxygen changes. Germinated seeds of maize (Zea mays L.) were planted in glass rhizotrons equipped with pH and oxygen-sensitive sensor foils. After 20 d, the rhizotrons were wetted from the bottom and time-lapsed images via fluorescence and neutron imaging were taken during the subsequent day and night cycles for 5 d. We found higher water content and stronger acidification in the first 0.5 mm from the root surface compared to the bulk soil, which could be a consequence of root exudation. While lateral roots only slightly acidified their rhizosphere, crown roots induced stronger acidification of up to 1 pH unit. We observed changing oxygen patterns at different soil moisture conditions and increasing towards lateral as well as crown roots while extending laterally with ongoing water logging. Our work indicates that plants alter the rhizosphere pH and oxygen also depending on root type, which may indirectly arise also from differences in age and water content changes. The results presented here were possible only by combining different imaging techniques to examine profiles at the root-soil interface in a comprehensive way during wetting and drying.
Background and Aims Dynamic processes occurring at the soil-root interface crucially influence soil physical, chemical and biological properties at a local scale around the roots, and are technically challenging to capture in situ. This study presents a novel multi-imaging approach combining fluorescence and neutron radiography that is able to simultaneously monitor root growth, water content distribution, root respiration and root exudation.
Methods Germinated seeds of white lupins (Lupinus albus) were planted in boron-free glass rhizotrons. After 11 d, the rhizotrons were wetted from the bottom and time series of fluorescence and neutron images were taken during the subsequent day and night cycles for 13 d. The following day (i.e. 25 d after planting) the rhizotrons were again wetted from the bottom and the measurements were repeated. Fluorescence sensor foils were attached to the inner sides of the glass and measurements of oxygen and pH were made on the basis of fluorescence intensity. The experimental set-up allowed for simultaneous fluorescence imaging and neutron radiography.
Key Results The interrelated patterns of root growth and distribution in the soil, root respiration, exudation and water uptake could all be studied non-destructively and at high temporal and spatial resolution. The older parts of the root system with greater root-length density were associated with fast decreases of water content and rapid changes in oxygen concentration. pH values around the roots located in areas with low soil water content were significantly lower than the rest of the root system.
Conclusions The results suggest that the combined imaging set-up developed here, incorporating fluorescence intensity measurements, is able to map important biogeochemical parameters in the soil around living plants with a spatial resolution that is sufficiently high enough to relate the patterns observed to the root system.
Xanthohumol (XN) is the principal prenylated flavonoid of the hop plant and has recently gained considerable interest due to its potential cancer-chemopreventive effects. However, the metabolism of XN has not yet been investigated in detail. Therefore, we studied the in vitro phase 11 metabolism of XN using nine human recombinant UDP- glucuronosyltransferases (UGT) and five sulfotransferases (SULT). The identification of the metabolites formed was elucidated using HPLC with diode array detection as well as HPLC/API-ES MS. XN was efficiently glucuronidated by UGT 1A8, 1A9, and 1A10; further important UGTs were UGT 1A1, 1A7, and 2B7. With respect to the sulfation reaction, SULT 1A1*2, 1A2, and 1E1 were the most active SULT forms. UGT 1A3, 1A4, and 1A6 as well as SULT 1A3 and 2A1 were of minor importance for the conjugation of XN. Three mono-glucuronides as well as three mono-sulfates were identified. Considering the tissue distribution of the tested UGT and SULT enzyme forms, these findings suggest a prominent role for the glucuronidation and sulfation of XN in the liver as well as in the gastrointestinal tract
Isoflavone intake is associated with various properties beneficial to human health which are related to their antioxidant activity, for example, to their ability to increase LDL oxidation resistance. However, the distribution of isoflavones among plasma lipoproteins has not yet been elucidated in vivo. Therefore, the objective of the present study was to investigate the association between daidzein (DAI) and lipoproteins in human plasma upon administration of the aglycone and glucoside form. Five men aged 22-30 years participated in a randomised, double-blind study in cross-over design. After ingestion of DAI and daidzein-7-O-beta-D-glucoside (DG) (1 mg DAI aglycone equivalents/kg body weight) blood samples were drawn before isoflavone administration as well as 1, 2, 3, 4.5, 6, 8, 10, 12, 24 and 48 h post-dose. Concentrations of DAI in the different lipoprotein fractions (chylomicrons, VLDL, LDL, HDL) and in the non-lipoprotein fraction were analysed using isotope dilution capillary GUMS. The lipoprotein fraction profiles were similar for all subjects and resembled those obtained for plasma in our previously published study. The lipoprotein distribution based on the area under the concentration-time profiles from 0 h to infinity in the different fractions were irrespective of the administered form: non-lipoprotein fraction (53%) > LDL (20%) > HDL (14%) > VLDL (9-5%) > chylomicrons (2-5%). Of DAI present in plasma, 47% was associated to lipoproteins. Concentrations in the different lipoprotein fractions as well as in the non-lipoprotein fraction were always higher after the ingestion of DG than of DAI. Taken together, these results demonstrate an association between isoflavones and plasma lipoproteins in vivo.
MADS-domain transcription factors have been shown to act as key repressors or activators of the transition to flowering and as master regulators of reproductive organ identities. Despite their important roles in plant development, the origin of several MADS-box subfamilies has remained enigmatic so far. Here we demonstrate, through a combination of genome synteny and phylogenetic reconstructions, the origin of three major, apparently angiosperm-specific MADS-box gene clades: FLOWERING LOCUS C- (FLC-), SQUAMOSA- (SQUA-) and SEPALLATA- (SEP-) -like genes. We find that these lineages derive from a single ancestral tandem duplication in a common ancestor of extant seed plants. Contrary to common belief, we show that FLC- like genes are present in cereals where they can also act as floral repressors responsive to prolonged cold or vernalization. This opens a new perspective on the translation of findings from Arabidopsis to cereal crops, in which vernalization was originally described.
The origin of flowers has puzzled plant biologists ever since Darwin referred to their sudden appearance in the fossil record as an abominable mystery. Flowers are considered to be an assembly of protective, attractive, and reproductive male and female leaf-like organs. Their origin cannot be understood by a morphological comparison to gymnosperms, their closest relatives, which develop separate male or female cones. Despite these morphological differences, gymnosperms and angiosperms possess a similar genetic toolbox consisting of phylogenetically related MADS domain proteins. Using ancestral MADS domain protein reconstruction, we trace the evolution of organ identity quartets along the stem lineage of crown angiosperms. We provide evidence that current floral quartets specifying male organ identity, which consist of four types of subunits, evolved from ancestral complexes of two types of subunits through gene duplication and integration of SEPALLATA proteins just before the origin of flowering plants. Our results suggest that protein interaction changes underlying this compositional shift were the result of a gradual and reversible evolutionary trajectory. Modeling shows that such compositional changes may have facilitated the evolution of the perfect, bisexual flower.
Equol has, as have other isoflavonoids, recently gained considerable interest due to its possible health effects. However, detailed studies on the metabolism of equol are scarce. Therefore, we investigated the phase I metabolism of equol using liver microsomes from Aroclor-treated male Wistar rats as well as from a male human. The identification of the metabolites formed was elucidated using high performance liquid chromatography ( HPLC) with diode array detection, HPLC/atmospheric pressure ionization electrospray mass spectrometry, and gas chromatography-mass spectrometry, as well as reference compounds. ( +/-)-Equol was converted to 11 metabolites by the liver microsomes from Aroclorpretreated rats comprising three aromatic monohydroxylated and four aliphatic monohydroxylated as well as four dihydroxylated products. The main metabolite was identified as 3'-hydroxy-equol. Using human liver microsomes, equol was converted to six metabolites with 3'-hydroxy- and 6-hydroxy-equol as main products. Furthermore, the aliphatic hydroxylated metabolite 4-hydroxyequol, which was recently detected in human urine after soy consumption, was formed. On the basis of these findings, it is suggested that phase I metabolism of equol is part of a complex biotransformation of the soy isoflavone daidzein in humans in vivo
Antioxidant activity of isoflavones and their major metabolites using different in vitro assays
(2006)
Isoflavone phytoestrogens found mainly in soybeans and clover are widely studied phytochemicals. Genistein and daidzein, the major isoflavones found in soy, have received the most attention. However, they undergo extensive metabolism in the intestine and the liver, which might affect their biological properties, e.g. their antioxidant capacities. Furthermore, the biological activities of other naturally occurring isoflavones, for instance, glycitein from soy or biochanin A from red clover, have not yet been studied in detail. The aim of this study was to investigate the antioxidant activities of six naturally occurring isoflavones and their corresponding oxidative and bacterial metabolites. The oxygen radical absorbance capacity assay as well as the in vitro oxidation of low density lipoproteins with the conjugated diene and the thiobarbituric acid reacting substances formation as end points were used. The oxidative metabolites of genistein and daidzein as well as equol exhibited the highest antioxidant activities in all three assays. With few exceptions, they were more effective than the positive controls quercetin and ascorbic acid. Formononetin, the 4'-O-methyl ether of daidzein, showed the lowest antioxidant property. Because the antioxidant efficacy of isoflavones as effective antioxidants is evident at concentrations well within the range found in the plasma of subjects consuming soy products, this biological activity could be of physiological relevance
Die Studie analysiert das brandenburgisch-preußische Gesandtschaftszeremoniell um 1700. Der Untersuchungszeitraum, von 1648 bis 1740, umfasst die Regentschaft dreier Hohenzollern, veranschaulicht vorhandene Kontinuitäten und erläutert den Einfluss einzelner Personen auf das Zeremoniell. Zugleich wird die Entwicklung des Gesandtschaftszeremoniells an sich über einen längeren Zeitraum verfolgt. Hier offenbart sich, die Vorgänge am und das Vorgehen des Berliner Hofes muten geradezu exemplarisch an. Die Hohenzollern waren Vertreter der allgemein vorherrschenden zeremoniellen Konjunkturen. In der vorliegenden Arbeit werden wiederkehrende Muster und Mechanismen des Gesandtschaftszeremoniells, sei es das Aufeinderbeziehen von Forderungen, der beständige Vergleich mit den übrigen Mächten oder die Darstellung von Abhängigkeiten, aufgezeigt. Es wird analysiert, welche Elemente einander bedingten, wie diese zusammenwirkten und welche Bestandteile häufig zu Diskussionen führten.
We consider a large population of globally coupled noisy phase oscillators. In the thermodynamic limit N this system exhibits a nonequilibrium phase transition, at which amacroscopic mean field appears. It is shown that for large but finite system size N the system can be described by the noisy Stuart-Landau equation, yielding scaling behavior of statistical characteristics of the macroscopic mean field with N. The predictions of the theory are checked numerically.
I. Keine europäischen Vorgaben zur Haftung II. Anwendung allgemeiner Amtshaftungsgrundsätze III. System der Amtshaftung in Deutschland IV. Maßgebliche Amtshandlungen des Einheitlichen Ansprechpartners V. Maßgebliche Amtshandlungen zuständiger Stellen VI. Amtshaftung wegen fehlender elektronischer Erreichbarkeit? VII. Haftende Körperschaft
Geschäftsbeurteilungen und -Erwartungen sind bedeutende Einflussgrößen in der Wirtschaft. Vor allem durch die Ereignisse der Finanzkrise der letzten Monate nahm die Diskussion um den Einfluss solch psychologisch basierter Faktoren zu. Die schillernden Begriffe wie Beurteilungen oder Erwartungen müssen zunächst quantifiziert werden, eine Aufgabe, die in der Regel von Forschungsinstituten wie Ifo, ZEW oder Eurostat übernommen wird. Dieser Diskussionsbeitrag untersucht, welche Möglichkeiten bestehen, die aktuellen Beurteilungen und zukünftigen Erwartungen in der Wirtschaft zu messen und wie dies konkret realisiert wird. Die Arbeit umfasst eine Datenbeschreibung und eine weitergehende Datenanalyse, in der die Zusammenhänge und Entwicklungen der einzelnen Zeitreihen untersucht werden. Eine der bedeutendsten Fragestellungen ist die Qualität und Reichwerte der Prognosekraft der Erwartungen für spätere Zeithorizonte. Ein internationaler Vergleich zwischen Deutschland und ausgewählten Länder der Europäischen Union sollen einen Überblick über die gemeinsame Entwicklung verschaffen. Als statistische Methoden werden unter anderem Hauptkomponentenanalysen und Partial-Least-Squares-Modelle verwendet.
Diese Forschungsarbeit widmet sich der Analyse von Stimmungen und Erwartungen im System der Märkte mit Dynamic Partial Least Squares (DPLS) Modellen. Die Analyse komplexer Systeme mit umfangreichen Datensätzen und die Erkennung relevanter Muster erfordern die Verwendung moderner statistischer Verfahren. DPLS-Modelle, eine Variante der Strukturgleichungs-modelle mit Latenten Variablen, werden methodisch erweitert, um mehrere zeitliche Verzögerungsstufen gleichzeitig modellieren zu können. Die ökonometrischen Modelle versuchen, zahlreiche latente Einflussfaktoren und ihre verdeckten Beziehungen zu identifizieren. Als Daten werden rund 80 Indikatoren verwendet von Januar 1991 bis Juni 2010, um Stimmungen, Erwartungen und wirtschaftlich relevanten Größen zu operationalisieren und die Zusammenhänge detailliert zu untersuchen. Die Modellergebnisse zeigen, dass Stimmungen, also die Einschätzung der aktuellen wirtschaftlichen Lage, deutlich mit wirtschaftlichen Größen zusammenhängen, unter anderem mit Investitionen, Auftragseingängen oder Aktienmarktentwicklungen. Die Erwartungen, also die Einschätzung der zukünftigen Entwicklung, bieten eine mittlere bis schwache Prognosekraft für sechs bis maximal achtzehn Monate in die Zukunft. Für kürzere Zeiträume von sechs Monaten sind Stimmungen und Erwartungen die besten verfügbaren Prognosevariablen. Die Analyse der Modellabweichungen erlaubt Rückschlüsse auf wirtschaftstheoretische Konzepte, wie Rationalität der Erwartungen. Auffällig sind scheinbare Phasen der systematischen Über- und Unterbewertungen der aktuellen Situation oder zukünftigen Entwicklung, insbesondere vor und nach Krisensituationen. Die Ergebnisse dieser Arbeit geben somit einen erweiterten Einblick in die empirischen Zusammenhänge subjektiver Einschätzungen mit realen wirtschaftlichen Größen.
Die vorliegende Untersuchung gibt einen Ausblick auf Prognosemöglichkeiten mit dynamischen Strukturgleichungsmodellen. Die Analyse komplexer Systeme mit umfangreichen Datensätzen und die Erkennung relevanter Muster erfordern die Verwendung moderner statistischer Verfahren. DPLS-Modelle, eine Variante der Strukturgleichungsmodelle mit Latenten Variablen, werden methodisch erweitert, um mehrere zeitliche Verzögerungsstufen gleichzeitig modellieren zu können. Die Modelle versuchen, zahlreiche latente Einflussfaktoren und ihre Wechselwirkungen zu identifizieren. Als Daten werden rund 80 Indikatoren aus 20 Quellen verwendet, um Stimmungen, Erwartungen und wirtschaftlich relevanten Größen zu operationalisieren und zeitliche Prognosemöglichkeiten zu evaluieren. Für kürzere Zeiträume von sechs Monaten sind Stimmungen und Erwartungen die besten verfügbaren Prognosevariablen. Dieser Beitrag ist entstanden im Rahmen eines Vortrages im gemeinsamen Forschungsseminar mit der Staatlichen Universität für Wirtschaft und Finanzen Sankt Petersburg Finec im Dezember 2010.
Der statistische Diskussionbeitrag untersucht, ob und wie sich Erwartungen und Stimmungen in der Wirtschaft bilden bzw. von welchen volkswirtschaftlichen Größen sie abhängen. Als Methodik werden Partial Least Squares (PLS) Modelle genutzt, eine Modellklasse der Pfadanalyse mit latenten Variablen. Die verwendeten Daten wurden vom Ifo-Institut und aus der amtlichen Statistik entnommen.
Dieser Beitrag reflektiert und ergänzt die aktuelle Diskussion über die Empfehlungen des Wissenschaftsrats zur Weiterentwicklung der Friedens- und Konfliktforschung. Wir richten dabei den Blick auf die vom Wissenschaftsrat attestierten Schwachstellen im Bereich empirisch-analytischer Methoden und erläutern ihre Auswirkungen auf Interdisziplinarität, Internationalität und Politikberatung der deutschen Friedens- und Konfliktforschung. Wir argumentieren, unter Verweis auf den Bericht des Wissenschaftsrats, dass eine breitere Methodenausbildung und -kenntnis von großer Bedeutung für interdisziplinäre und internationale Zusammenarbeit, aber auch für die Politikberatung ist. Zukünftige Initiativen innerhalb der Friedens- und Konfliktforschung sollten die Methodenvielfalt des Forschungsbereichs angemessen berücksichtigen und einen besonderen Fokus auf die Ausbildung im Bereich empirisch-analytischer Methoden legen, um das Forschungsfeld in diesem Bereich zu stärken. Unser Beitrag entspringt einer Diskussion innerhalb des Arbeitskreises „Empirische Methoden der Friedens- und Konfliktforschung“ der Arbeitsgemeinschaft Friedens- und Konfliktforschung.
The active metabolite of vitaminA, retinoic acid (RA), plays an important role in the female reproductive system. The synthesis of RA is tightly regulated by the activity of retinaldehyde dehydrogenases (Raldh). Among these, Raldh1 and Raldh2 exhibit specific temporal and spatial expression patterns in the mouse uterus, both during the oestrous cycle and early pregnancy. In the present study, we have assessed whether oestradiol and progesterone directly influence the uterine expression of Raldh1 and Raldh2 in ovariectomised mice. We investigated the effect of gestagen (promegestone 0.3 mg kg(-1) bodyweight), oestrogen (oestradiol 3 mu g kg(-1) bodyweight) and their combination on the uterine expression of Raldh2. Expression was analysed using in situ hybridisation and quantified using real-time detection reverse transcription-polymerase chain reaction. The results show that the expression of Raldh2 is rapidly (within 1-4 h) induced in stromal cells by oestrogen, but not by gestagen, treatment, whereas combined oestrogen + gestagen treatment leads to a more prolonged (48 h) response. In contrast, oestrogen, but not progesterone, treatment downregulates (within 4 - 24 h) Raldh1 expression in the uterine glandular epithelium. We conclude that the uterine RA concentrations are regulated by oestrogens via an effect on the expression of the Raldh synthesising enzymes. Such a regulation is consistent with the natural fluctuations of Raldh expression during the oestrous cycle, early pregnancy and blastocyst implantation
What’s “Drache“ in English?
(2023)
Liquid crystalline side group polymers with azo-chromophores and fluorinated tails of varying length
(1996)
Quo vadis, Mindanao?
(2017)
Collagen is the most abundant protein in mammals. In many tissues, collagen molecules assemble to form a hierarchical structure. In the smallest supramolecular unit, named fibril, each molecule is displaced in the axial direction with respect to its neighbors. This staggering creates a periodic gap and overlap regions, where the gap regions exhibit 20% less density. These fibril-forming collagens play an essential role in the strength of connective tissues. Despite much effort, directed at understanding collagen function and regulation, the influence of the chemical environment on the local structural and mechanical properties remains poorly understood. Recent studies, aimed at elucidating the effect of osmotic pressure, showed that collagen contracts upon water removal. This observation highlights the importance of water for the stabilization and mechanics of the collagen molecule.
Using collagen mimetic peptides (CMPs), which fold into triple helical structures reminiscent of natural collagen, the primary goal of this work was to investigate the effect of the osmotic pressure on specific collagen-mimetic sequences. CMPs were used as the model system as they provide sequence control, which is essential for discriminating local from global structural changes and for relating the observed effects to existing knowledge about the full-length collagen molecule. Of specific interest was the structure of individual collagen triple helices as well as their organization into self-assembled higher order structures. These key structural features were monitored with infrared spectroscopy (IR) and synchrotron X-ray scattering, while varying the osmotic pressure. For controlling the osmotic pressure, CMP powder samples were incubated in air of defined relative humidity, ranging from dry conditions to highly “humid”. In addition, to obtain more biologically relevant conditions, the CMPs were measured in ultrapure water and in solutions containing small molecule osmolytes.
Using the sequences (Pro-Pro-Gly)10, (Pro-Hyp-Gly)10 and (Hyp-Hyp-Gly)10, it was shown that CMPs with different degrees of proline hydroxylation (Hyp = hydroxyproline) exhibit a sequence-specific response to osmotic pressure. IR spectroscopy revealed that osmotic pressure changes affect the strength of the triple helix stabilizing, interchain hydrogen bond and that the extent of this change depends on the degree of hydroxylation. X-ray scattering experiments further showed that changes in osmotic pressure affect both the molecular length as well as the higher order organization of CMPs. Starting from a pseudo-hexagonal packing in the dry state, all three CMPs showed isotropic swelling when increasing the water content to approximately 1.2 water molecules per amino acid, again to different extents depending on the degree of hydroxylation. When increasing the water content further, this pseudo-hexagonal arrangement breaks down. In the fully hydrated state, each CMP is characterized by its own specific and more complex packing geometry.
While these changes in the lateral packing arrangement suggest swelling upon hydration, an overall decrease of the molecular length (i.e. contraction) was observed in the axial direction. Also for this structural feature, a strong dependency on the specific amino acid sequence was found. Interestingly, the observed contraction is the opposite of what has been reported for natural collagen. As (Pro-Pro-Gly)n, (Pro-Hyp-Gly)n and (Hyp-Hyp-Gly)n repeat units are found in collagen with a relatively high abundance, this suggests that other collagen sequence fragments need to respond to hydration in the opposite way to obtain a net elongation of the full-length collagen molecule.
To test this hypothesis, sequences predicted to be sensitive to osmotic pressure were considered. One such sequence, consisting of two repeat units (Ala-Arg-Gly-Ser-Asp-Gly), was inserted as a guest into a (Pro-Pro-Gly) host. When compared to the canonical CMP sequences investigated earlier, the lateral helix packing follows a similar trend with increasing hydration; however, the host-guest CMP axially elongates with increasing water content. This behavior is more similar to what has been found for natural collagen and suggests that different sequences do determine the molecular length of collagen sequences differently. Interestingly, the canonical sequences are more abundant in the overlap region while the guest sequence is found in the gap region. This allows to speculate that sequences in the gap and overlap regions possess a specifically fine-tuned local response to osmotic pressure changes. Clearly, more experiments with additional sequences are needed to confirm this.
In conclusion, the results obtained in this work indicate a highly sequence specific interaction between collagen and water. Osmotic pressure-induced conformational changes mostly originate from local geometries and bonding patterns and affect both the structure of individual triple helices as well as higher order assemblies. One key remaining question is how these conformational changes affect the local mechanical properties of the collagen molecule. As a first step, the stiffness (persistence length) of full-length collagen was determined using atomic force microscopy. In the future, experimental strategies need to be developed that allow for investigating the mechanical properties of specific collagen sequences, e.g. performing single-molecule force spectroscopy of CMPs.
Photon Density Wave (PDW) spectroscopy was applied for temperature dependent monitoring of melting and crystallization of milk fat within homogenized fresh milk. As an in-line process analytical technique, PDW spectroscopy quantifies continuously the optical properties of turbid material, providing an insight into its structural processes. Here, the measured absorption coefficients reflect temperature as well as fat content of milk and the reduced scattering coefficients probe physical changes of the light scattering fat droplets and casein micelles. Thermal processing reveals breakpoints within the temperature trend of the reduced scattering coefficient of fat containing milk. Found at 16 degrees C and 24 degrees C while cooling and heating, respectively, they are associated to the phase transitions of milk fat. Continuous isothermal measurement of the optical coefficients showed that the crystallization process requires several hours. The strongly changing reduced scattering coefficient implies that the thermal history of milk will have a major impact on any method based on light scattering as quantitative analytical technique.
This dissertation was carried out as part of the international and interdisciplinary graduate school StRATEGy. This group has set itself the goal of investigating geological processes that take place on different temporal and spatial scales and have shaped the southern central Andes. This study focuses on claystones and carbonates of the Yacoraite Fm. that were deposited between Maastricht and Dan in the Cretaceous Salta Rift Basin. The former rift basin is located in northwest Argentina and is divided into the sub-basins Tres Cruces, Metán-Alemanía and Lomas de Olmedo. The overall motivation for this study was to gain new knowledge about the evolution of marine and lacustrine conditions during the Yacoraite Fm. Deposit in the Tres Cruces and Metán-Alemanía sub-basins. Other important aspects that were examined within the scope of this dissertation are the conversion of organic matter from Yacoraite Fm. into oil and its genetic relationship to selected oils produced and natural oil spills. The results of my study show that the Yacoraite Fm. began to be deposited under marine conditions and that a lacustrine environment developed by the end of the deposition in the Tres Cruces and Metán-Alemanía Basins. In general, the kerogen of Yacoraite Fm. consists mainly of the kerogen types II, III and II / III mixtures. Kerogen type III is mainly found in samples from the Yacoraite Fm., whose TOC values are low. Due to the adsorption of hydrocarbons on the mineral surfaces (mineral matrix effect), the content of type III kerogen with Rock-Eval pyrolysis in these samples could be overestimated. Investigations using organic petrography show that the organic particles of Yacoraite Fm. mainly consist of alginites and some vitrinite-like particles. The pyrolysis GC of the rock samples showed that the Yacoraite Fm. generates low-sulfur oils with a predominantly low-wax, paraffinic-naphthenic-aromatic composition and paraffinic wax-rich oils. Small proportions of paraffinic, low-wax oils and a gas condensate-generating facies are also predicted. Here, too, mineral matrix effects were taken into account, which can lead to a quantitative overestimation of the gas-forming character.
The results of an additional 1D tank modeling carried out show that the beginning (10% TR) of the oil genesis took place between ≈10 Ma and ≈4 Ma. Most of the oil (from ≈50% to 65%) was generated prior to the development of structural traps formed during the Plio-Pleistocene Diaguita deformation phase. Only ≈10% of the total oil generated was formed and potentially trapped after the formation of structural traps. Important factors in the risk assessment of this petroleum system, which can determine the small amounts of generated and migrated oil, are the generally low TOC contents and the variable thickness of the Yacoraite Fm. Additional risks are associated with a low density of information about potentially existing reservoir structures and the quality of the overburden.