Abbildendes Raman Deuterium Stable Isotope Probing von Fluidgemischen in Tropfen und Mikrokanälen

Die Verdunstung von komplexen Gemischen ist im täglichen Leben allgegenwärtig. Beim Malen, Tintenstrahldrucken und Kleben verdunsten Lösemittel, während andere relevante Bestandteile der Farbe, Tinte oder des Klebstoffs auf der Oberfläche haften bleiben. Auch wenn Flüssigkeiten auf Oberflächen (ungewollt) eintrocknen und Rückstände zurückbleiben, spielt die Verdunstung bei diesen Trocknungsprozessen eine große Rolle. Die einzelnen Komponenten verdampfen unterschiedlich schnell, wodurch sich Konzentrationsgradienten in den Gemischen bilden, die mithilfe der Ramanspektroskopie charakterisiert werden können.Werden chemisch ähnliche Substanzen untersucht, muss eine Komponente davon chemisch markiert werden, damit die Substanzen mit der Ramanspektroskopie unterschieden werden können. Diese Methode wird zum Beispiel auch beim Raman Deuterium Stable Isotope Probing praktiziert. Eine Art der Markierung kann die Substitution von Wasserstoffatomen durch Deuteriumatome sein. Mit dieser Arbeit konnte die Raman Deuterium Stable Isotope Probing Methode zur Untersuchung chemisch ähnlicher Substanzen an zwei Beispielsystemen und -versuchsaufbauten etabliert werden. Um Mischungsverhältnisse und Mischungsverhalten von Fluiden auch in derMikrofluidik untersuchen zu können, wurden Experimente mit Ramanspektroskopie in Mikrokanälen durchgeführt. Für die Ramanspektroskopie benötigen die verwendeten Mikrosysteme eine hohe Transparenz, weshalb eine Methode für den 3D Druck transparenter Mikrosysteme entwickelt wurde. Das Drucken transparenter Bauteile (für verschiedene Anwendungen) ist mit stereolithographischem 3D Druck möglich. Ein kommerziell erhältlicher 3D Drucker wurde modifiziert, um die Transparenz der gedruckten Bauteile zu erhöhen. Mithilfe dieser Konfiguration wurde die Transparenz der Bauteile so weit erhöht, dass sie für die Ramanspektroskopie verwendet werden können. Durch die Kombination beider Methoden – Raman Deuterium stable isotope probing und transparenter 3D Druck – wurde eine Möglichkeit geschaffen, das Mischungsverhalten chemisch ähnlicher Substanzen in 3D gedruckten Mikrokanälen zu charakterisieren

Berry phase in entangled systems: a proposed experiment with single neutrons

The influence of the geometric phase, in particular the Berry phase, on an entangled spin-1/2 system is studied. We discuss in detail the case, where the geometric phase is generated only by one part of the Hilbert space. We are able to cancel the effects of the dynamical phase by using the ``spin-echo'' method. We analyze how the Berry phase affects the Bell angles and the maximal violation of a Bell inequality. Furthermore we suggest an experimental realization of our setup within neutron interferometry.Comment: 10 pages, 6 figures, Introduction extended, References adde

Engineering of triply entangled states in a single-neutron system

We implemented a triply entangled Greenberger-Horne-Zeilinger(GHZ)-like state and coherently manipulated the spin, path, and energy degrees of freedom in a single neutron system. The GHZ-like state was analyzed with an inequality derived by Mermin: we determined the four expectation values and finally obtained M = 2.558 +/- 0.004 > 2, which exhibits a clear violation of the noncontextual assumption and confirms quantum contextuality.Comment: 4 pages, 2figure

Energy entanglement in neutron interferometry

Entanglement between degrees of freedom, namely between the spin, path and (total) energy degrees of freedom, for single neutrons is exploited. We implemented a triply entangled Greenberger-Horne-Zeilinger(GHZ)-like state and coherently manipulated relative phases of two-level quantum subsystems. An inequality derived by Mermin was applied to analyze the generated GHZ-like state: we determined the four expectation values and finally obtained M=2.558 +/- 0.004 which is clearly above the threshold of 2. This demonstrates the violation of a Mermin-like inequality for triply entangled GHZ-like state in a single-particle system, which, in turn, exhibits a clear inconsistency between noncontextual assumptions and quantum mechanics and confirms quantum contextuality.Comment: 4 pages, 3 figure

Kochen-Specker theorem studied with neutron interferometer

The Kochen-Specker theorem theoretically shows evidence of the incompatibility of noncontextual hidden variable theories with quantum mechanics. Quantum contextuality is a more general concept than quantum non-locality which is quite well tested in experiments by using Bell inequalities. Within neutron interferometry we performed an experimental test of the Kochen-Specker theorem with an inequality, which identifies quantum contextuality, by using spin-path entanglement in a single neutron system. Here entanglement is achieved not between different particles, but between degrees of freedom, i.e., between spin and path degree of freedom. Appropriate combinations of the spin analysis and the position of the phase shifter allow an experimental verification of the violation of an inequality of the Kochen-Specker theorem. The observed value of (2.291 +/- 0.008), which is above the threshold of 1, clearly shows that quantum mechanical predictions cannot be reproduced by noncontextual hidden variable theories.Comment: 5 pages, 3 figure

Curricular Quality and Day-To-Day Learning Activities in Pre-School

The purpose of this paper is to show how curricular quality is related to the day-to-day activities experienced by children and the pedagogical activities of staff, both coded through systematic target child observations. Data were drawn from the Effective Provision of Pre-School Education (EPPE) and the Researching Effective Pedagogy in the Early Years Project (REPEY) studies. Curricular quality was measured by coding the ECERS-E, an English curricular extension to the well known ECERS-R. In centres scoring high on the ECERS-E, staff engaged in pedagogical practices that included more ‘sustained shared thinking’ and more ‘direct teaching’ such as questioning or modeling. In high scoring centres, children were also observed participating in more activities associated with early reading, emergent writing and active listening. Children in centres assessed as ‘adequate’ spent more time in activities associated with the ‘Physical Development’ and ‘Creative’ curriculum. Thus the ECERS-E gives higher scores to pedagogical practices and activities where staff take a more active role in children’s learning, including scaffolding young children’s play, especially in the communication and literacy domains of the curriculum

Finding critical action learning through paradox:the role of action learning in the suppression and stimulation of critical reflection

In this article, we highlight paradoxical tensions generated by in-company action learning. We consider the implications of these tensions for critical action learning, which has critical reflection as a core element of its theory and practice. Using paradox theory as a lens, we analyze data from two in-company action learning programs and build a model relating to critical action learning that has four interlinked features. The model can help evaluate in-company action learning with a view to identifying emotional and political dynamics that are open (or closed) to critical reflection. Such identification assists in making judgements about the appropriateness of critical action learning within a specific organizational context. Our broader contribution is to frame action learning and critical action learning not only as separate approaches but also as potentially interlinked stages in an ongoing process of individual and organizational learning. </jats:p

The mito-QC reporter for quantitative mitophagy assessment in primary retinal ganglion cells and experimental glaucoma models

This research was funded by Ministerio de Ciencia, Innovación y Universidades (MCIU), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) PGC2018-098557-B-I00 and European Union’s Horizon 2020 research and innovation programme under grant agreement No 765912. BVZ is a recipient of PhD contract from the Fundación Tatiana Pérez de Guzmán el Bueno (Spain), PT from H2020-MSCA-ITN-2017, NRM a Juan de la Cierva Grant from Ministerio Ciencia e Innovación (Spain) and KB from DFG (Deutsche Forschungsgemeinschaft, Germany, 6619/1-1).Mitochondrial damage plays a prominent role in glaucoma. The only way cells can degrade whole mitochondria is via autophagy, in a process called mitophagy. Thus, studying mitophagy in the context of glaucoma is essential to understand the disease. Up to date limited tools are available for analyzing mitophagy in vivo. We have taken advantage of the mito-QC reporter, a recently generated mouse model that allows an accurate mitophagy assessment to fill this gap. We used primary RGCs and retinal explants derived from mito-QC mice to quantify mitophagy activation in vitro and ex vivo. We also analyzed mitophagy in retinal ganglion cells (RGCs), in vivo, using different mitophagy inducers, as well as after optic nerve crush (ONC) in mice, a commonly used surgical procedure to model glaucoma. Using mito-QC reporter we quantified mitophagy induced by several known inducers in primary RGCs in vitro, ex vivo and in vivo. We also found that RGCs were rescued from some glaucoma relevant stress factors by incubation with the iron chelator deferiprone (DFP). Thus, the mito-QC reporter-based model is a valuable tool for accurately analyzing mitophagy in the context of glaucoma.publishersversionpublishe

New method to study ion-molecule reactions at low temperatures and application to the H2+_2^+ + H2_2 →\rightarrow H3+_3^+ + H reaction

Studies of ion-molecule reactions at low temperatures are difficult because stray electric fields in the reaction volume affect the kinetic energy of charged reaction partners. We describe a new experimental approach to study ion-molecule reactions at low temperatures and present, as example, a measurement of the ${\rm H}_2^+ + {\rm H}_2\rightarrow {\rm H}_3^+ + {\rm H}$ reaction with the ${\rm H}_2^+$ ion prepared in a single rovibrational state at collision energies in the range $E_{\rm col}/k_{\rm B} = 5$-60 K. To reach such low collision energies, we use a merged-beam approach and observe the reaction within the orbit of a Rydberg electron, which shields the ions from stray fields. The first beam is a supersonic beam of pure ground-state H$_2$ molecules and the second is a supersonic beam of H$_2$ molecules excited to Rydberg-Stark states of principal quantum number $n$ selected in the range 20-40. Initially, the two beams propagate along axes separated by an angle of 10$^\circ$. To merge the two beams, the Rydberg molecules in the latter beam are deflected using a surface-electrode Rydberg-Stark deflector. The collision energies of the merged beams are determined by measuring the velocity distributions of the two beams and they are adjusted by changing the temperature of the pulsed valve used to generate the ground-state ${\rm H}_2$ beam and by adapting the electric-potential functions to the electrodes of the deflector. The collision energy is varied down to below $E_{\rm col}/k_{\rm B}= 10$ K, i.e., below $E_{\rm col}\approx 1$ meV, with an energy resolution of 100 $\mu$eV. We demonstrate that the Rydberg electron acts as a spectator and does not affect the cross sections, which are found to closely follow a classical-Langevin-capture model in the collision-energy range investigated. Because all neutral atoms and molecules can be excited to Rydberg states, this method of studyingComment: 39 pages, 10 figure