Luminescence tuning of MOFs via ligand to metal and metal to metal energy transfer by co-doping of 2∞[Gd2Cl6(bipy)3]*2bipy with europium and terbium

The series of anhydrous lanthanide chlorides LnCl3, Ln=Pr–Tb, and 4,4'-bipyridine (bipy) constitute isotypic MOFs of the formula 2∞[Ln2Cl6(bipy)3]*2bipy. The europium and terbium containing compounds both exhibit luminescence of the referring trivalent lanthanide ions, giving a red luminescence for Eu3+ and a green luminescence for Tb3+ triggered by an efficient antenna effect of the 4,4'-bipyridine linkers. Mixing of different lanthanides in one MOF structure was undertaken to investigate the potential of this MOF system for colour tuning of the luminescence. Based on the gadolinium containing compound, co-doping with different amounts of europium and terbium proves successful and yields solid solutions of the formula 2∞[Gd2-x-yEuxTbyCl6(bipy)3]*2bipy (1–8), 0≤x, y≤0.5. The series of MOFs exhibits the opportunity of tuning the emission colour in-between green and red. Depending on the atomic ratio Gd:Eu:Tb, the yellow region was covered for the first time for an oxygen/carboxylate-free MOF system. In addition to a ligand to metal energy transfer (LMET) from the lowest ligand-centered triplet state of 4,4'-bipyridine, a metal to metal energy transfer (MMET) between 4f-levels from Tb3+ to Eu3+ is as well vital for the emission colour. However, no involvement of Gd3+ in energy transfers is observed rendering it a suitable host lattice ion and connectivity centre for diluting the other two rare earth ions in the solid state. The materials retain their luminescence during activation of the MOFs for microporosity

Mehrskalen-2D-Mechanik : von Quanten zu Festkörpern, von Graphen zu Betonplatten

Abweichender Titel nach Übersetzung der Verfasserin/des Verfassers2D Mechanik von dünnen Strukturelementen in Kombination mit Fourierreihen-basierten Ver- schiebungsansätzen dient als eine effiziente Art und Weise zur Bestimmung von Deformations- und Spannungsgrößen. Neben der Recheneffizienz infolge der gewählten kinematischen Annahmen bezüglich des Strukturelements, werden energetisch konsistente Kontinuummodelle für thermo- elastische dünne Platten und Membrane für beliebige Randbedingungen hergeleitet. In diesem Zusammenhang wird das Prinzip der virtuellen Leistungen angewendet, um die strikte Unterschei- dung zwischen internen und externen Kräften sicherzustellen. Dieses vielseitige Prinzip liefert weiters ein Lösungsverfahren in Form von algebraischen Gleichungssystemen zur Bestimmung der Fourierkoeffizienten der obengenannten Reihendarstellung der gesuchten Verschiebungen.In der vorliegenden Arbeit wird die semianalytische Methode auf Strukturprobleme von dünnen elastisch gebetteten Betonplatten sowie von freistehenden Graphenmembranen unter großen Deformationen angewendet. Die Modellierung der Betonplatten erfolgt durch Kirchhoffsche Platten auf elastischer Winkler Bettung mit spannungsfreien Randbedingungen. Dabei wird von klassischen linear-thermoelastischen Spannungs-Dehungsbeziehungen zur Beschreibung des isotro- pen Materialverhalten ausgegangen. Das konstitutive Materialverhalten von Graphen hingegen ist noch in der Anfangsphase der Entwicklung. Hierbei handelt es sich um das erste tatsächliche 2D Material mit unübertroffenen mechanischen Eigenschaften, bestehend aus Kohlenstoffatomen, die in einem einschichtigen hexagonalen Gitter angeordnet sind. Als Lösungsansatz für diese Situation wird eine invariante hyperelastische Formulierung des vollständig nichtlinearen aniso- tropen Materialverhalten entwickelt. Dieses verfeinerte Model basiert auf quantenmechanischen Energiesimulationen von Zehntausenden beliebigen biaxialen Verzerrungszuständen, bis zu den elastischen Stabilitätsgrenzen von Graphen.Solch dünne Strukturelemente werden mehreren Typen von vertikalen mechanischen Kräften sowie Temperaturgradienten über die Elementdicke unterworfen. Die temperaturinduzierten Belastungen werden durch Simulationen von extremen Wetterverhältnissen motiviert, nämlich Hagelschauer nach starker Sonneneinstrahlung auf Straßen oder Flugplätzen. Die numerischen Ergebnisse der bereitgestellten Anwendungen werden durch Vergleich mit Daten von experi- mentellen Messungen und Finite Elemente Analysen validiert. In Bezug auf letztere kann das reihenbasierte Lösungsverfahren die Rechenzeit um einen Faktor von bis zu vierzig verkürzen.2D mechanics of thin structural elements in combination with Fourier series-based approximative displacement fields serves as an efficient way to determine deformation and stress measures. Along with computational efficiency due to the kinematic assumptions regarding the structural element, energetically consistent continuum models for thermoelastic thin plates and membranes with arbitrary boundary conditions are derived. In this context, the Principle of Virtual Power is applied in order to ensure a rigorous discrimination of internal and external forces. This versatile principle further yields a solution procedure in form of an algebraic system of equations for the Fourier coefficients of the aforementioned series representation of the sought displacements.In the present thesis, the semi-analytical method is applied to structural problems of thin elastically supported concrete slabs and to suspended graphene membranes undergoing large deformations. The concrete slabs are modeled as Kirchhoff plates resting on elastic Winkler foundations with stress-free boundary conditions, where classical linear thermoelastic stress-strain relations are used for describing the constitutive isotropic material behavior. For graphene, the first true 2D material with unsurpassed mechanical properties, consisting of carbon atoms arranged in a monolayer hexagonal lattice, the constitutive material behavior is still in its infancy. As a remedy to this situation, an invariant hyperelastic formulation of the fully nonlinear anisotropic material behavior is developed. This refined model is based on quantum mechanics- rooted energy simulations associated with tens of thousands of arbitrary biaxial strain states up to graphene’s elastic stability limits.Such thin structural elements are subjected to several types of vertical mechanical forces and to temperature gradients along the element’s thickness. The temperature-induced loads are motivated to simulate extreme weather events, namely hail showers following significant solar heating, appearing on roads and airfields for example. The numerical results of the provided applications are validated through comparison with predictions obtained from experimental measurements and Finite Element analysis. With respect to the latter, the series-based solution procedure may reduce computer time by a factor of almost forty.22

Modellierung schwimmender Estriche als gebettete Platten oder geschichtete Halbräume? Auswirkungen auf die Dimensionierung

Zusammenfassung in deutscher SpracheAbweichender Titel nach Übersetzung der Verfasserin/des VerfassersDie Bemessung von Fußbodenaufbauten erfolgt in aktuellen Normen durch die Beschränkung von Zugspannungen an der Unterseite von elastisch gebetteten Platten, welche anhand der Theorie von Westergaard ermittelt werden. Dadurch ergeben sich in der Regel höhere Estrichdicken gegenüber bisherigen Regelungen, was zu wirtschaftlichen und ökologischen Herausforderungen führt. Die vorliegende Arbeit widmet sich möglichen Lösungsansätzen für diese Situation. Zunächst wird aus zahlreichen Beiträgen zur Theorie von Westergaard diejenige mathematische Formulierung für elastisch gebettete Platten identifiziert, welche tatsächlich für die Estrichbemessung verwendet wird. Bei dieser Untersuchung stellte sich heraus, dass Einzellasten am Estrichrand maßgebend für die Ermittlung der maximalen Spannungen sind. Die zugehörigen kritischen Spannungen treten an der Unterkante des Estrichs auf, direkt an die elastische Bettung angrenzend. Diese kritischen Spannungen werden in aktuellen Normen zur Angabe von Mindestdicken für Estriche herangezogen. Westergaards Lösungen für die Ermittlung von Spannungen basieren auf der Annahme, dass Spannungen orthogonal zur Plattenmittelebene vernachlässigbar sind. Westergaards Theorie liefert also obere Schranken für die tatsächlich auftretenden Spannungen. In anderen Worten, die Verwendung einer verfeinerten Theorie würde zu niedrigeren Spannungen und damit zu niedrigeren erforderlichen Plattendicken führen. Das ist die Motivation, die Theorie des elastisch geschichteten Halbraums von Pan auf die Mechanik schwimmender Estriche anzuwenden. Eine solche Anpassung liefert nach längerer Ableitung besonders recheneffiziente Lösungen für Spannungen und Verschiebungen unterhalb einer in der Mitte liegenden Belastung. Weiters zeigt der Vergleich der Ergebnisse einer Reihe von 3D Finite Elemente Simulationen von einerseits in der Mitte und andererseits am Rand belasteten, geschichteten Fußbodensystemen, dass die kritischen Zugspannungen an der Unterseite des Estrichs kaum von der Lastangriffsposition abhängen. Daher bietet die angepasste Theorie von Pan einen verfeinerten, effektiven rechnerischen Zugang zu den kritischen Zugspannungen. Diese Methode ermöglicht Verringerungen der Estrichdicken um typischerweise 10 %, im Vergleich zu den Vorgaben der aktuellen österreichischen Norm. Eine weitere Reduzierung der Spannungen kann durch einen geschichteten Estrichaufbau erreicht werden - basierend auf Pans Lösungen.Recent regulations for floor design are based on tensile stress restrictions on the lower face of elastically bedded plates according to the theory of Westergaard. As a result, screed layer thicknesses now often have be increased with respect to the former regulations, and this causes economical and ecological challenges. The present thesis is devoted to potential remedies to this situation. First of all, the precise mathematical relations used for the plate-based floor design are identified from the various contributions of Westergaard on the theory of elastically bedded plates. In more detail, it turned out that it is the solution for the maximum tensile stress occurring at an edge of the lower surface of such a plate (i.e. of the surface adjacent to the elastic foundation) which was used for defining the requirements for screed thicknesses. This stress solution is based on the assumption that normal stresses orthogonal to the plane of the plate are negligible - hence, it is an upper bound for the actually occurring stress. In other words, use of a more refined theory would result in lower stresses, and hence lower required thicknesses. This is the motivation to adapt the theory of layered elastic half spaces, as proposed by Pan, to the case of floating floor screed. Such an adaptation provides, after quite lengthy derivations, solutions of particular computational efficiency, for the stresses and displacements below a load situated rather in the middle, than on the edge of a floating floor screed. However, comparison with a series of 3D Finite Element simulations of layered floor systems loaded in the center and at the edges, respectively, provide evidence that this position change of the load does only faintly affect the critical tensile stresses occurring at the bottom of the floor screed. Hence, the adaptation of Pan's theory provides a refined, computationally effective access to critical tensile stresses; allowing for a reduction of floor thicknesses by typically 10 %; when compared to current Austrian code recommendations. Further reduction of stresses can be achieved by a layered floor design - again based on Pan's solutions.7

Triple-induction treatment for locally advanced non-small cell lung cancer: a case report of pathological complete response

Abstract Background In patients with resectable stage III non-small cell lung cancer (NSCLC), induction chemoimmunotherapy followed by surgical resection has shown unprecedented rates of pathological response and event-free survival. However, a triple-induction including radiochemotherapy and immunotherapy followed by surgical resection has not been routinely established in clinical practice. Case presentation We report the case of a 47-year-old patient with stage IIIA NSCLC who was treated in a combined concept including induction concurrent radiochemotherapy, followed by 4 cycles of pembrolizumab and subsequent intrapericardial left-sided pneumonectomy. Histological analysis revealed a pathological complete response. Conclusions The case demonstrates that the combination of neoadjuvant chemo-, radio- and immunotherapy in advanced NSCLC may lead to a relevant down-staging and may enable a R0-resection of a borderline resectable tumor. However, the combination of four different treatment modalities requires resilience and a good performance status. A triple induction treatment may be a promising option for selected patients with locally advanced NSCLC and good performance status

Impaired wound healing in an acute diabetic pig model and the effects of local hyperglycemia

Diabetic wounds result in significant morbidity, prolonged hospitalization, and enormous health-care expenses. Pigs have been shown to have wound healing resembling that in humans. The aim of this study was to develop a large-animal model for diabetic wound healing. Diabetes was induced by streptozotocin injection in Yorkshire pigs. Full-thickness wounds were created and dressed with a sealed chamber. Nondiabetic pigs with or without high glucose wound fluid concentration served as controls. Glucose concentration in serum and wound fluid was measured and collected. Wound contraction was monitored, and biopsies were obtained for measurement of reepithelialization. Wound fluid was analyzed for insulin-like growth factor-1 (IGF-1), platelet-derived growth factor, and transforming growth factor. Glucose concentration in wound fluid initially followed serum levels and then decreased to undetectable on day 9. Reepithelialization was significantly delayed in diabetic pigs. In nondiabetic pigs, wounds treated in a local hyperglycemic environment, and thus excluding the effects of systemic hyperglycemia, showed no difference in wound closure compared with controls. This suggests that delayed wound healing in diabetes is not induced by local high-glucose concentration itself. Analysis of growth factor expression showed a marked reduction in IGF-1 in the diabetic wounds. Diabetic pigs have impaired healing that is accompanied by a reduction of IGF-1 in the healing wound and is not due to the local hyperglycemia condition itself