Influence of different silica nanoparticles on drop size distributions in agitated liquid‐liquid systems

The impact of different silica nanoparticles on rheology, interfacial tension and drop size distributions in liquid‐liquid systems is determined experimentally. The particles vary in wettability and specific surface area. In contrast to commonly used high‐energy devices for Pickering emulsion preparation, low energy input by stirring allows to quantify drop breakage and coalescence in steady state and dynamic conditions. The experiments can provide essential information for drop size model development in nanoparticle‐stabilized emulsions.DFG, 56091768, TRR 63: Integrierte chemische Prozesse in flüssigen MehrphasensystemenTU Berlin, Open-Access-Mittel - 201

Maximum Incorporation of Soft Microgel at Interfaces of Water in Oil Emulsion Droplets Stabilized by Solid Silica Spheres

The incorporation of soft hydrophilic particles at the interface of water in non-polar oil emulsion droplets is crucial for several applications. However, the stabilization of water in non-polar oil emulsions with hydrophilic soft material alone is, besides certain exceptions, not possible. In our previous works, we showed that stabilizing the emulsions with well-characterized spherical hydrophobic silica nanospheres (SNs) and soft equally charged microgel particles (MGs) is a robust strategy to stabilize w/o emulsions while still incorporating a large amount of MGs at the interface. In the present study, we address the question of what the maximum amount of MGs at the interface in these kinds of emulsion droplets can be. By using well-characterized mono-disperse SNs, we are able to calculate the fraction of interface covered by the SNs and complementary that of the present MG. We found that it is not possible to decrease the SN coverage below 56% irrespective of MG softness and SN size. The findings elucidate new perspectives to the broader topic of soft/solid stabilized emulsions

„Ich wollte Venedig einfangen, ich wollte es beschreiben“ – Wolfgang Koeppen und das Ende der Reiseliteratur

Erhart W. „Ich wollte Venedig einfangen, ich wollte es beschreiben“ – Wolfgang Koeppen und das Ende der Reiseliteratur. In: Ecker G, Röhl S, eds. In Spuren Reisen. Vor-Bilder und Vor-Schriften in der Reiseliteratur. Münster: Lit-Verlag; 2006: 187-206

Changes in organic matter composition during the Toarcian Oceanic Anoxic Event (T-OAE) in the Posidonia Shale Formation from Dormettingen (SW-Germany)

During the Early Toarcian, deposition of organic carbon-rich-shales occurred throughout the epicontinental sea across Europe. Climate instability and high extinction rates in the marine realm were associated with profound environmental changes. The Toarcian Oceanic Anoxic Event (T-OAE) has been linked to the injection of greenhouse gases (e.g. oceanic methane) into the atmosphere triggered by the emplacement of the Karoo-Ferrar large igneous province (LIP) volcanism. The data presented are obtained from the Posidonia Shale Formation in Dormettingen (southwestern Germany), ~2 km from the well-known Dotternhausen section. Despite the intense palaeontological and geochemical research, studies on the particulate organic matter (POM) across the T-OAE are scarce. Here, we provide a detailed study of POM of the Dormettingen section as a tool to evaluate changes in the depositional environment. Integrated POM (i.e. amorphous organic matter, marine and terrestrial palynomorphs) and geochemical (i.e. carbon isotope δ13C) analyses reveal different episodes of palaeoecological upheavals during the studied time interval. In this study, we will integrate new palynofacies data and combine it with the existing sedimentological and palaeoecological data of Dotternhausen in order to interpret relative sea-level fluctuations and climatic changes at the local palaeogeographic setting.ISSN:0031-0182ISSN:1872-616

Application of Population Balance Models in Particle-Stabilized Dispersions

In this study, a first approach to model drop size distributions in agitated nanoparticle-stabilized liquid/liquid systems with population balance equations is presented. Established coalescence efficiency models fail to predict the effect of steric hindrance of nanoparticles at the liquid/liquid interface during the film drainage process. A novel modified coalescence efficiency is developed for the population balance framework based on the film drainage model. The elaborate submodel considers the desorption energy required to detach a particle from the interface, representing an energy barrier against coalescence. With an additional implemented function in the population balance framework, the interface coverage rate by particles is calculated for each time step. The transient change of the coverage degree of the phase interface by particles is thereby considered in the submodel. Validation of the modified submodel was performed with experimental data of agitated water-in-oil (w/o) dispersions, stabilized by well-defined spherical silica nanoparticles. The nanospheres with a size of 28 nm are positively charged and were hydrophobized by silanization with dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammoniumchloride. This modeling approach is a first step toward predicting time-resolved dynamic drop size distributions of nanoparticle-stabilized liquid/liquid systems

Cytokine Profiles of Head and Neck Squamous Cell Carcinoma Undergoing Dual Immunotherapy With Cetuximab and Pembrolizumab Identify Interferon Gamma-Induced Protein 10 as Novel Biomarker

Background: Pembrolizumab and cetuximab are antibodies under investigation in head and neck squamous cell carcinoma (HNSCC) either as single agents or combined with cisplatin and other chemotherapeutic drugs, e.g., 5-fluorouracil and/or docetaxel. However, also the combination of both antibodies may have potential in recurrent/ metastatic (R/M) HNSCC, in particular in cisplatin-resistant or -refractory cases or patients with comorbid disease, e.g. patients with impaired renal function. Methods: To clarify potential benefit that may result from such combination, we used the FLAVINO assay, a short-time ex vivo assay to compare responsiveness of HNSCC to pembrolizumab, cetuximab and both combined regarding colony formation of epithelial cells of biopsy-derived tumor samples and their cytokine production within three days either without or with stimulation with 10 ng/mL interferon gamma (IFN-g). Vascular endothelial growth factor A (VEGF), monocyte chemoattractant protein 1 (MCP-1 or CCL2), interleukin 6 (IL-6), IL-8, IFN-g, and interferon gamma-induced protein 10 (IP-10 or CXCL10) in supernatants were measured by ELISA. Results: We detected huge heterogeneity in response to cetuximab, pembrolizumab and both combined with and without IFN-g stimulation. Moreover, we detected a link between IFN-g induced IP-10 release and improved outcome in those HNSCC patients who were capable to respond to IFN-g and pembrolizumab, cetuximab and both combined with a further increase in IP-10 production. We derived an “IP-10 score” that independent from clinical characteristics of HNSCC patients and therapy regimens applied was able to predict their outcome. Conclusions: The heterogeneity in the ex vivo response of cetuximab, pembrolizumab and both combined with and without IFN-g stimulation identifies subgroups of HNSCC patients with deviating OS