PPAR Gamma Activators: Off-Target Against Glioma Cell Migration and Brain Invasion

Today, there is increasing evidence that PPARγ agonists, including thiazolidinediones (TDZs) and nonthiazolidinediones, block the motility and invasiveness of glioma cells and other highly migratory tumor entities. However, the mechanism(s) by which PPARγ activators mediate their antimigratory and anti-invasive properties remains elusive. This letter gives a short review on the debate and adds to the current knowledge by applying a PPARγ inactive derivative of the TDZ troglitazone (Rezulin) which potently counteracts experimental glioma progression in a PPARγ independent manner

Synthese und Modifikation von Calciumsilicathydrat-Phasen

Eine der wichtigsten Eigenschaften von Beton bzw. Zement ist die hohe Druckfestigkeit des jeweiligen Materials, die Zugfestigkeit (z. B. Biegezugfestigkeit) ist dagegen um ein Vielfaches geringer. Durch Verbesserung der mechanischen Eigenschaften der Hauptkomponente von hydratisiertem Zement, Calciumsilicathydrat (C-S-H) in nanokristalliner Form, könnte damit eventuell auch die Zugfestigkeit des Zements an sich verbessert werden. Einen ersten Schritt in diese Richtung stellt die Modifikation reiner C-S-H-Phasen im Labormaßstab dar. Auf dem Gebiet der Modifikation von C-S-H-Phasen wurde in den letzten Jahrzehnten intensiv geforscht. Obwohl große Anstrengungen unternommen wurden, um eine mögliche Interkalation, sprich die Einlagerung organischer Moleküle in die Zwischenschichten der C-S-H-Struktur, zu ermöglichen, konnte bisher kein endgültiger Nachweis für die echte Interkalation organischer Moleküle in den interlamellaren Bereich von C-S-H-Phasen erbracht werden. In der vorliegenden Arbeit wurde die Synthese von Calciumsilicathydraten sowie deren Modifizierung mit organischen Precursoren hinsichtlich einer möglichen Interkalation bzw. der Bildung von Hybriden untersucht. Dazu wurden anhand verschiedener Syntheserouten sowohl nanokristalline Phasen mit geringer struktureller Ordnung als auch kristalline Phasen mit hoher struktureller Ordnung synthetisiert und charakterisiert. Interkalationsversuche wurden an nanokristallinen und an kristallinen Proben durchgeführt. Dabei wurden die zu interkalierenden Moleküle (verschiedene Alkoxysilane und Polymere) direkt während der Synthese eingesetzt. Zusätzlich wurden Ca-Organohybridverbindungen mit Alkoxysilanen als einziger Si-Quelle hergestellt, was im Idealfall zur Ausbildung von Schichtverbindungen mit organischen Spacern führt.One of the most important features of concrete and cement is its high compressive strength while the tensile strength (e.g. tensile strength in bending) of the material is significantly lower. The improvement of the mechanic properties of the main compound of hydrated cement, calciumsilicatehydrate (C-S-H) in nanocrystalline form, could therefore lead to an improvement of the tensile strength. The modification of pure C-S-H in a laboratory scale would be a first step towards this improvement. The modification of C-S-H has been subject to extensive research for the last decades. While great efforts have been made to provide a potential way to intercalate organic moieties into the interlayer spacing of the C-S-H structure, a proof for true intercalation in this spacing of C-S-H phases could not yet be provided. This work deals with the synthesis of calciumsilicatehydrates and the modification of these phases with organic precursors to evaluate a possible intercalation or formation of hybrids. Nanocrystalline phases with minor structural order as well as crystalline phases with high structural order were synthesized and characterized using different synthesis routes. Intercalation experiments were performed with nanocrystalline and crystalline samples. The molecules used for intercalation (several alkoxysilanes and polymers) were directly added during synthesis of the samples. Calcium organosilicate hybrid compounds were synthesized with alkoxysilanes as sole silicon source which ideally leads to the formation of a layered structure with organic spacers

3D characterization of microstructured poly(methacrylic acid) thin films via Mach-Zehnder interference microscopy

We demonstrate the adaption of a further developed Mach–Zehnder interference (MZI) microscope for the rapid 3D characterization of transparent microstructured polymer thin films. In order to quantify the accuracy of the Mach-Zehnder interferometer, comparative film thickness measurements of photolithographically patterned poly(methacrylic acid) polymer brushes are performed employing two alternative techniques: white light profilometry (WIM) and atomic force microscopy (AFM). When the refractive index of the polymer brushes is calculated from MZI data, we obtain a good agreement with results received from an independent method (ellipsometry). In contrast to surface probing techniques such as AFM or WIM, Mach-Zehnder interferometry is a transmitted light method that measures both surface height profiles and refractive index distributions. MZI thus enables the quantification of film homogeneity with respect to height and density variations at the lateral resolution of a refraction limited microscope. We conclude that MZI is an adequate tool for the rapid and non-destructive characterization of structured polymer thin films. This method should be particularly useful for production quality control of microstructured polymer thin films which possess great potential in electronic device fabrication and biotechnology