Experimental studies of nucleation and growth processes related to the formation of presolar grains

An understanding was sought for the mechanisms of nucleation of refractory materials, and the relative importance of factors controlling the rate of cluster formation and growth for astrophysically important species. The structure and composition of the condensates is being studied, with the goal of characterizing the grains present in the primitive solar nebula

Formation of iron metal and grain coagulation in the solar nebula

The interstellar grain population in the giant molecular cloud from which the sun formed contained little or no iron metal. However, thermal processing of individual interstellar silicates in the solar nebula is likely to result in the formation of a population of very small iron metal grains. If such grains are exposed to even transient magnetic fields, each will become a tiny dipole magnet capable of interacting with other such dipoles over spatial scale orders of magnitude larger than the radii of individual grains. Such interactions will greatly increase the coagulation cross-section for this grain population. Furthermore, the magnetic attraction between two iron dipoles will significantly increase both the collisional sticking coefficient and the strength of the interparticle binding energy for iron aggregates. Formation of iron metal may therefore be a key step in the aggregation of planetesimals in a protoplanetary nebula. Such aggregates may have already been observed in protoplanetary systems. The enhancement in the effective interaction distance between two magnetic dipoles is directly proportional to the strength of the magnetic dipoles and inversely proportional to the relative velocity. It is less sensitive to the reduced mass of the interacting particles (alpha M(exp -1/2)) and almost insensitive to the initial number density of magnetic dipoles (alpha n(sub o)(exp 1/6)). We are in the process of measuring the degree of coagulation in our condensation flow apparatus as a function of applied magnetic field and correlating these results by means of magnetic remanance acquisition measurements on our iron grains with the strength of the magnetic field to which the grains are exposed. Results of our magnetic remanance acquisition measurements and the magnetic-induced coagulation study will be presented as well as an estimate of the importance of such processes near the nebular midplane

A novel Malonamide Periodic Mesoporous Organosilica (PMO) for controlled Ibuprofen release

Controlled drug release gained a sharply increasing interest over recent years. Multiple materials have been screened as possible drug carriers, ranging from biodegradable polymers to hydroxyapatite[1]. Periodic Mesoporous Organosilicas are valuable alternatives as they possess a high chemical and thermal stability combined with a biocompatible nature[2]. Furthermore, their large internal surface area permits a high drug loading. Careful selection of the organic ‘bridged’ functionality allows a controlled release with respect to external stimuli, such as pH or temperature, of the drugs which are adsorbed via weak and reversible interactions, e.g. H-bonding, ionic and hydrophobic-phobic interaction[3]. In this contribution a novel malonamide (MA-PMO) and a methyl-malonamide PMO (mMA-PMO) bearing a high amount of functionalities, capable of multiple intramolecular interactions, are developed and thoroughly characterized[4]. Subsequently, these hybrid materials are evaluated in the controlled drug release of Ibuprofen

Refugees on Their Way to German Higher Education: A Capabilities and Engagements Perspective on Aspirations, Challenges and Support

In recent years, the number of new asylum applications in Germany has risen with a peak in 2015. Many refugees arrive with high levels of prior education and corresponding educational aspirations. Hence, German universities and preparatory colleges (so-called ‘Studienkollegs’) have created additional preparatory courses and supporting services for refugees. Heretofore, little is known about the specific challenges for prospective refugee students seeking access to higher education in the German context. We focus on key individual, social, and institutional conditions for integrating refugees into the German higher education system. How do prospective refugee students value higher education? What are the key challenges and supporting factors on their way to higher education in Germany? Our analysis is based on 17 exploratory interviews with prospective refugee students, staff of higher education institutions and counselling services. We combine educational sociology and refugee studies and rely on the capability approach and its close relation to the conception of agency to theorize our empirical findings. Reconstructing the challenges and coping strategies along with the key concepts of the capability approach reveals the different strategies of prospective refugee students to achieve their aspirations as well as the frustrating institutional limits of agency. Finally, we will discuss implications for higher education policy in Germany