Röntgenreflektometrie und diffuse Röntgenstreuung zur Charakterisierung von Grenzflächenrauheiten und Grenzflächenmorphologien im Bereich der Nanometrologie

Die Charakterisierung von ultradünnen Schichtsystemen mit der diffusen Röntgenstreuung in koplanarer Geometrie (DXRS) wird auf ihre Eignung für die industrielle Praxis untersucht. Die Röntgenreflektometrie (XRR) ist eine der DXRS inhärente Methode zur tast- und zerstörungsfreien Messung ultradünner Schichtdicken (d < 100 nm), die kurzfristig als metrologisches Instrument etabliert werden kann. Es werden Untersuchungen an unterschiedlichen Prototypen für Schichtdickennormale durchgeführt, die belegen, dass die DXRS hohe metrologische Anforderungen in Bezug auf die Messgenauigkeit erfüllt und somit als Referenzmethode geeignet ist. Im Fall der diffusen Röntgenstreuung werden zusätzlich zur spekulären Reflexion die angrenzenden diffusen Streuanteile gemessen. Diese enthalten detaillierte Informationen über die statistischen Eigenschaften der Grenzflächen von Vielschichtsystemen im Hinblick auf ihre Morphologie. Die Arbeiten zielen auf den mittelfristigen Einsatz der Röntgenstreuung im Bereich der Nanometrologie. Messungen an verschiedenen Vielschichtsystemen demonstrieren den Einsatz der Methode und umreißen die ermittelbaren Grenzflächenparameter wie Rauheiten und Korrelationslängen. Zusätzlich belegen sie die Realisierbarkeit der Methode an einem Labormessplatz. Die zur Interpretation der Streubilder erforderliche Theorie, die die Basis für eine numerische Simulation bilden, werden vorgestellt. Auf der Basis auf den durchgeführten Messungen und den theoretischen Untersuchungen wird die Anwendung der diffusen Röntgenstreuung in der Nanometrologie diskutiert.The use of diffuse X-ray scattering in coplanar geometry (DXRS) for the characterization of ultra thin film multilayers is investigated with respect to its use in industrial application. X-ray reflectometry (XRR) is a technique in the framework of DXRS. XRR is a non-contact and non-destructive method to measure the thickness of ultra-thin solid films (d < 100 nm), which is to be used as a metrological instrument in the near future. Investigations carried out on different prototypes of film thickness standards are presented to demonstrate the high accuracy of DXRS. In the case of DXRS, the diffuse scattered part of the radiation is measured in addition to the specular part and contains the information about the statistical properties of the interface of the multilayer. This provides access to the systems morphology. The aim of the work is to prepare DXRS technique for use in nanometrology in the next years. Measurements on different samples are used to present DXRS in practical application and to demonstrate the interface parameter provided by the method, such as interface roughness or correlation length. In addition it is proved, that DXRS can be realized on small laboratory scale. The basic theory of DXRS for interpretation of the scattering images is briefly introduced. The theory is also a starting point for the numerical simualtion of the scattering process. A discussion about the use of DXRS in nanomorphology is held on the basis of the experimental and theoretical results

Associations between stress and migraine and tension-type headache: Results from a school-based study in adolescents from grammar schools in Germany

Introduction: Stress is considered the major contributor to migraine and tension-type headache in adolescents. Previous studies have focused on general stressors, whereas the aim of the present study was to investigate associations between individuals’ stressful experiences and different types of headache. Methods: Adolescents from 10th and 11th grades of grammar schools filled in questionnaires. Stressful experiences were measured with the Trier Inventory of Chronic Stress. Type of headache was classified according to the International Classification of Headache Disorders. Linear regressions, adjusted for sex and grade, were calculated to estimate differences in stress scores that can be attributed to migraine, tension-type headache or miscellaneous headache. Results: A total of 1260 questionnaires were analysed. Tension-type headache, migraine and co-existing migraine plus tension-type headache were found in 48.7%, 10.2% and 19.8% of the participants. In subjects with migraine or co-existing migraine plus tension-type headache, high increases in stress scores were found in all investigated dimensions, whereas much weaker and inconsistent associations were found in subjects with tension-type headache only. Conclusions: The characteristic of migraine is more associated with stressful experiences than this is the case for tensiontype headache. This suggests that adolescent migraine patients might specially benefit from behavioural interventions regarding stress

From perception to action: phase-locked gamma oscillations correlate with reaction times in a speeded response task

<p>Abstract</p> <p>Background</p> <p>Phase-locked gamma oscillations have so far mainly been described in relation to perceptual processes such as sensation, attention or memory matching. Due to its very short latency (≈90 ms) such oscillations are a plausible candidate for very rapid integration of sensory and motor processes.</p> <p>Results</p> <p>We measured EEG in 13 healthy participants in a speeded reaction task. Participants had to press a button as fast as possible whenever a visual stimulus was presented. The stimulus was always identical and did not have to be discriminated from other possible stimuli. In trials in which the participants showed a fast response, a slow negative potential over central electrodes starting approximately 800 ms before the response and highly phase-locked gamma oscillations over central and posterior electrodes between 90 and 140 ms after the stimulus were observed. In trials in which the participants showed a slow response, no slow negative potential was observed and phase-locked gamma oscillations were significantly reduced. Furthermore, for slow response trials the phase-locked gamma oscillations were significantly delayed with respect to fast response trials.</p> <p>Conclusion</p> <p>These results indicate the relevance of phase-locked gamma oscillations for very fast (not necessarily detailed) integration processes.</p

Cross-competition of CD8+ T cells shapes the immunodominance hierarchy during boost vaccination

CD8+ T cell responses directed against multiple pathogen-derived epitopes are characterized by defined immunodominance hierarchy patterns. A possible explanation for this phenomenon is that CD8+ T cells of different specificities compete for access to epitopes on antigen-presenting cells, and that the outcome of this so-called cross-competition reflects the number of induced T cells. In our study using a vaccinia virus infection model, we found that T cell cross-competition is highly relevant during boost vaccination, thereby shaping the immunodominance hierarchy in the recall. We demonstrate that competition was of no importance during priming and was unaffected by the applied route of immunization. It strongly depended on the timing of viral antigen expression in infected APCs, and it was characterized by poor proliferation of T cells recognizing epitopes derived from late viral proteins. To our knowledge, this is the first demonstration of the functional importance of T cell cross-competition during a viral infection. Our findings provide a basis for novel strategies for how boost vaccination to defined antigens can be selectively improved. They give important new insights into the design of more efficient poxviral vectors for immunotherapy

The Correlation of the NA Measurements by Counting 28Si Atoms

open12sìpartially_openembargoed_20160715Mana, G.; Massa, E.; Sasso, C. P.; Stock, M.; Fujii, K.; Kuramoto, N.; Mizushima, S.; Narukawa, T.; Borys, M.; Busch, I.; Nicolaus, A.; Pramann, A.Mana, Giovanni; Massa, Enrico; Sasso, CARLO PAOLO; Stock, M.; Fujii, K.; Kuramoto, N.; Mizushima, S.; Narukawa, T.; Borys, M.; Busch, I.; Nicolaus, A.; Pramann, A

Prognostic Value of Different CMR-Based Techniques to Assess Left Ventricular Myocardial Strain in Takotsubo Syndrome

Cardiac magnetic resonance (CMR)-derived left ventricular (LV) global longitudinal strain (GLS) provides incremental prognostic information on various cardiovascular diseases but has not yet been investigated comprehensively in patients with Takotsubo syndrome (TS). This study evaluated the prognostic value of feature tracking (FT) GLS, tissue tracking (TT) GLS, and fast manual long axis strain (LAS) in 147 patients with TS, who underwent CMR at a median of 2 days after admission. Long-term mortality was assessed 3 years after the acute event. In contrast to LV ejection fraction and tissue characteristics, impaired FT-GLS, TT-GLS and fast manual LAS were associated with adverse outcome. The best cutoff points for the prediction of long-term mortality were similar with all three approaches: FT-GLS −11.28%, TT-GLS −11.45%, and fast manual LAS −10.86%. Long-term mortality rates were significantly higher in patients with FT-GLS > −11.28% (25.0% versus 9.8%; p = 0.029), TT-GLS > −11.45% (20.0% versus 5.4%; p = 0.016), and LAS > −10.86% (23.3% versus 6.6%; p = 0.014). However, in multivariable analysis, diabetes mellitus (p = 0.001), atrial fibrillation (p = 0.001), malignancy (p = 0.006), and physical triggers (p = 0.006) outperformed measures of myocardial strain and emerged as the strongest, independent predictors of long-term mortality in TS. In conclusion, CMR-based longitudinal strain provides valuable prognostic information in patients with TS, regardless of the utilized technique of assessment. Long-term mortality, however, is mainly determined by comorbidities

Time Pressure Modulates Electrophysiological Correlates of Early Visual Processing

BACKGROUND: Reactions to sensory events sometimes require quick responses whereas at other times they require a high degree of accuracy-usually resulting in slower responses. It is important to understand whether visual processing under different response speed requirements employs different neural mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: We asked participants to classify visual patterns with different levels of detail as real-world or non-sense objects. In one condition, participants were to respond immediately, whereas in the other they responded after a delay of 1 second. As expected, participants performed more accurately in delayed response trials. This effect was pronounced for stimuli with a high level of detail. These behavioral effects were accompanied by modulations of stimulus related EEG gamma oscillations which are an electrophysiological correlate of early visual processing. In trials requiring speeded responses, early stimulus-locked oscillations discriminated real-world and non-sense objects irrespective of the level of detail. For stimuli with a higher level of detail, oscillatory power in a later time window discriminated real-world and non-sense objects irrespective of response speed requirements. CONCLUSIONS/SIGNIFICANCE: Thus, it seems plausible to assume that different response speed requirements trigger different dynamics of processing