Ein neues magmatisch-tektonisches Modell zur Asthenosphärendynamik im Bereich der zentralandinen Subduktionszone Südamerikas

Im Rahmen der Dissertation wurden an Wässern und freien Gasen aus Thermalquellen sowie an weniger als 5 Millionen Jahre alten basischen Vulkaniten des zentralandinen Puna-Hochplateaus (NE-Argentinien) umfangreiche element- und isotopengeochemische Untersuchungen durchgeführt und die Edelgasgehalte und -isotopensignaturen in diesen Medien bestimmt. Damit soll ein Beitrag zum besseren Verständnis der jüngeren Subduktionsgeschichte im Bereich der südlichen Zentralanden geleistet, die Wechselwirkungen zwischen ozeanischer Unter- und kontinentaler Oberplatte sichtbar gemacht und die Edelgassystematik verbessert werden. Wie die Ergebnisse der Untersuchungen an Gasen aus den Thermalquellen der Puna-Region zeigen, ist der Anteil an Mantel-Helium in den Thermalquellen dieser Region mit bis zu 67 % wesentlich höher als in der westlich gelegenen vulkanisch aktiven Westkordillere und den anderen angrenzenden Gebieten. In einigen Quellen konnten sogar Anteile an Mantel-Neon nachgewiesen werden, was aufgrund von Überlagerungen mit Neon atmosphärischen und krustalen Ursprungs weltweit bisher nur vereinzelt gelungen ist. Für kontinentale Bereiche mit großer Krustendicke ist ein solch starker Mantelgasfluss äußerst ungewöhnlich und bedeutet, dass Mantelschmelzen bis in die Kruste aufgedrungen sind und tief reichende Wegsamkeiten existieren, so dass die Mantelgase aufsteigen können, ohne stark krustal beeinflusst zu werden. Dass im Bereich der Puna rezent Mantelmaterial in die Kruste aufsteigt, zu diesem Ergebnis kommen auch aktuelle seismologische Untersuchungen...thesi

Vitamin D supplementation after the menopause

The purpose of this review was to assess recent evidence regarding the effects of low vitamin D levels on some highly prevalent clinical conditions of postmenopausal women. We reviewed and selected recent literature regarding menopause-related conditions associated with vitamin D deficiency and interventions to manage them. Low circulating 25-hydroxyvitamin D (25(OH)D) levels related to menopause are linked to diet, lifestyle, changes in body composition, insulin sensitivity, and reduced physical activity. Vitamin D supplementation increases serum 25(OH)D levels while normalizing parathyroid hormone and bone markers, and in women with serum 25(OH)D levels below 10 ng/ml supplementation may improve bone mineral density. Low vitamin D status has been associated with the metabolic syndrome, high triglyceride levels, and low high-density lipoprotein cholesterol levels. When compared with placebo, vitamin D supplementation may lower the risk of the metabolic syndrome, hypertriglyceridemia, and hyperglycemia. There is an inverse relationship between fat mass and serum 25(OH)D levels and, therefore, the dosage of supplementation should be adjusted according to the body mass index. Although vitamin D supplementation may improve glucose metabolism in prediabetic subjects, data regarding muscle strength are conflictive. There is evidence that vitamin D over-treatment, to reach extremely high circulating 25(OH)D levels, does not result in better clinical outcomes. The identification and treatment of vitamin D deficiency in postmenopausal women may improve their general health and health outcomes. Vitamin D supplementation should preferably be based on the use of either cholecalciferol or calcifediol

Investigating the Static Recrystallization Behavior of 22MnB5 Manganese–Boron Steel through Stress Relaxation Analysis

A constitutive model was developed to characterize the static recrystallization (SRX) and evolution of the grain size of the industrially relevant press-hardening steel, 22MnB5, subsequent to the hot forming of sheet metal. Isothermal stress relaxation tests were conducted using the BAEHR 805 A/D thermomechanical simulator, encompassing a temperature range of 950 to 1050 °C, prestrain levels ranging from 0.01 to 0.1, and strain rates spanning from 0.01 to 0.8 s−1. The results obtained from the isothermal stress relaxation tests facilitated the formulation of an Avrami equation-based model, which aptly describes the kinetics of SRX in relation to the temperature, prestrain, and strain rate. Notably, an increase in temperature led to accelerated recrystallization kinetics, signifying temperature-dependent behavior. When the temperature increased from 950 to 1050 °C, the recrystallization time was reduced to approximately one-third. Additionally, the prestrain exhibited a positive influence on the acceleration of SRX kinetics. A quintupling of the prestrain from 0.01 to 0.05 resulted in a reduction of the static recrystallization duration to approximately one-fifth. Among the parameters studied, the strain rate had the least impact on the SRX kinetics, as doubling the strain rate from 0.01 to 0.8 only resulted in a halving of the recrystallization duration. Moreover, an analysis of the microstructural evolution in response to the forming parameters was undertaken. While the grain-size investigation post-isothermal stress relaxation tests provided results in line with the SRX kinetics calculations, the observed effects were comparatively subdued. Furthermore, a comprehensive examination was conducted using electron backscatter diffraction (EBSD) analysis, aiming to explore the effects of specific stress relaxation states on the morphology of martensite. The findings reveal fully recrystallized globulitic microstructures, characterized by relatively minor differences among them

Measurements of H2 Solubility in Saline Solutions under Reservoir Conditions: Preliminary Results from Project H2STORE

AbstractA high-pressure/high-temperature reactor has been used to lead PVT and H2-solubility experiments in saline solutions covering conditions for which no data are available in literature: salinity up to halite concentration, pressure up to 200bar and temperature up to 373K. The hereby presented preliminary results show significant deviations from theoretical models. Further analysis and more measurements are needed to assess precision and reproducibility of these measurements; however they pinpoint the importance of experimental work to reliably constrain predictive models

Habituation of reflexive and motivated behavior in mice with deficient BK channel function.

Habituation is considered the most basic form of learning. It describes the decrease of a behavioral response to a repeated non-threatening sensory stimulus and therefore provides an important sensory filtering mechanism. While some neuronal pathways mediating habituation are well described, underlying cellular/molecular mechanisms are not yet fully understood. In general, there is an agreement that short-term and long-term habituation are based on different mechanisms. Historically, a distinction has also been made between habituation of motivated versus reflexive behavior. In recent studies in invertebrates the large conductance voltage- and calcium-activated potassium (BK) channel has been implicated to be a key player in habituation by regulating synaptic transmission. Here, we tested mice deficient for the pore forming α-subunit of the BK channel for short-term and long-term habituation of the acoustic startle reflex (reflexive behavior) and of the exploratory locomotor behavior in the open field box (motivated behavior). Short-term habituation of startle was completely abolished in the BK knock-out mice, whereas neither long-term habituation of startle nor habituation of motivated behavior was affected by the BK deficiency. Our results support a highly preserved mechanism for short-term habituation of startle across species that is distinct from long-term habituation mechanisms. It also supports the notion that there are different mechanisms underlying habituation of motivated behavior versus reflexive behavior

Übergangsprozesse von der Schule in die Erwerbstätigkeit in Japan und Deutschland im Kontext von Beruflichkeit und Stratifizierung

Die Autoren betrachten Übergangsprozesse von der Schule in die Erwerbstätigkeit am Beispiel der beiden Nationalstaaten Japan und Deutschland. Vor dem Hintergrund der von ihnen skizzierten, in beiden Staaten gänzlich unterschiedlichen Berufsschulsysteme und gesetzlichen Vorgaben zur Einmündung in die Erwerbstätigkeit untersuchen sie die Rolle der Beruflichkeit im Kontext der Übergangsproblematik und den Einfluss der Stratifizierung. Sie schließen mit einigen Überlegungen dazu, wie die in Japan formal geringe Stratifizierung des Übergangs durch eine indirekte Stratifizierung konterkariert wird. (DIPF/Orig.)The transition process from school into employment is a well known research object in international comparisons. This article will focus on two special issues. On the one hand this will be the comparison between Japan and Germany, two countries with very different (vocational) education systems and labour market entry regulations. On the other hand it will focus on two different aspects in the transition process: One is the role of \u27vocationalism\u27 (Berufskonzept) and the other is the stratification in the systems of education and training. For Japan an indirect type of stratification and no vocationalism can be found. In contrast to that a direct type of stratification is very common in Germany and vocationalism plays a major role in the transition process. Japan, however, even without direct stratification and vocationalism is very successfull in managing the transition process. Here the high ratio of academic education, the relatively unspecific vocational education combined with expanded internal training after entering a company as well as the yet important close link between the employee and the company are important factors. (DIPF/Orig.

Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway

BACKGROUND: Short-term habituation of the startle response represents an elementary form of learning in mammals. The underlying mechanism is located within the primary startle pathway, presumably at sensory synapses on giant neurons in the caudal pontine reticular nucleus (PnC). Short trains of action potentials in sensory afferent fibers induce depression of synaptic responses in PnC giant neurons, a phenomenon that has been proposed to be the cellular correlate for short-term habituation. We address here the question whether both this synaptic depression and the short-term habituation of the startle response are localized at the presynaptic terminals of sensory afferents. If this is confirmed, it would imply that these processes take place prior to multimodal signal integration, rather than occurring at postsynaptic sites on PnC giant neurons that directly drive motor neurons. RESULTS: Patch-clamp recordings in vitro were combined with behavioral experiments; synaptic depression was specific for the input pathway stimulated and did not affect signals elicited by other sensory afferents. Concordant with this, short-term habituation of the acoustic startle response in behavioral experiments did not influence tactile startle response amplitudes and vice versa. Further electrophysiological analysis showed that the passive properties of the postsynaptic neuron were unchanged but revealed some alterations in short-term plasticity during depression. Moreover, depression was induced only by trains of presynaptic action potentials and not by single pulses. There was no evidence for transmitter receptor desensitization. In summary, the data indicates that the synaptic depression mechanism is located presynaptically. CONCLUSION: Our electrophysiological and behavioral data strongly indicate that synaptic depression in the PnC as well as short-term habituation are located in the sensory part of the startle pathway, namely at the axon terminals of sensory afferents in the PnC. Our results further corroborate the link between synaptic depression and short-term habituation of the startle response

Fully Automated Optimization of Robot‐Based MOF Thin Film Growth via Machine Learning Approaches

Metal–organic frameworks (MOFs), have emerged as ideal class of materials for the identification of structure–property relationships and for the targeted design of multifunctional materials for diverse applications. While the powder form is most common, for the integration of MOFs into devices, typically thin films of surface anchored MOFs (SURMOFs), are required. Although the quality of SURMOFs emerging from layer-by-layer approaches is impressive, previous works revealed that the optimum growth conditions are very different between different types of MOFs and different substrates. Furthermore, the choice of appropriate synthesis conditions (e.g., solvents, modulators, concentrations, immersion times) is crucial for the growth process and needs to be adjusted for different substrates. Machine learning (ML) approaches show great promise for multi-parameter optimization problems such as the above discussed growth conditions for SURMOF on a particular substrate. Here, this work presents an ML-based approach allowing to quickly identify optimized growth conditions for HKUST-I SURMOFs with high crystallinity and uniform orientation. This process can subsequently be used to optimize growth on other types of substrates. In addition, an analysis of the results allows to gain further insights into the factors governing the growth of MOF thin films

Keratinocytes regulate the threshold of inflammation by inhibiting T cell effector functions

Whilst the importance of keratinocytes as a first-line defense has been widely investigated, little is known about their interactions with non-resident immune cells. In this study, the impact of human keratinocytes on T cell effector functions was analyzed in an antigen-specific in vitro model of allergic contact dermatitis (ACD) to nickel sulfate. Keratinocytes partially inhibited T cell proliferation and cytokine production. This effect was dependent on the keratinocyte/T cell ratio and was partially reversible by increasing the number of autologous dendritic cells. The inhibition of T cell proliferation by keratinocytes was independent of the T cell subtype and antigen presentation by different professional antigen-presenting cells. Autologous and heterologous keratinocytes showed comparable effects, while the fixation of keratinocytes with paraformaldehyde abrogated the immunosuppressive effect. The separation of keratinocytes and T cells by a transwell chamber, as well as a cell-free keratinocyte supernatant, inhibited T cell effector functions to the same amount as directly co-cultured keratinocytes, thus proving that soluble factor/s account for the observed suppressive effects. In conclusion, keratinocytes critically control the threshold of inflammatory processes in the skin by inhibiting T cell proliferation and cytokine production