Some heuristics about the ecosystem of mathematics research data

Like in other sciences, research data play a growing role in mathematics, but in contrast to classical objects like measurements in physics they are much more heterogeneous. They may take the shape of abstract objects like the collection of integer sequences in OEIS, algorithms and their implementations as mathematical software, libraries of test problems or statistical data. From an infrastructure viewpoint, which aims at sustainable and connected data repositories which facilitate researchers to use existing information efficiently, it is essential to define an appropriate framework that allows not just storage but also connection and retrieval of the various types of data. Recently, there have been promising attempts to define standards for mathematical software, but the general task remains a big challenge, which is also addressed within the recently initiated GDML working group of the IMU. This is especially important in the fields of applied mathematics where research is often connected to research data originating from applications. The goal of this talk is a first attempt to analyse the diverse ecosystem of research data based on reference data from zbMATH. This approach has worked quite well for mathematical software, resulting in the formation of the swMATH database. Though reference data involve always a bias, the collected information of about 16 million reference data in zbMATH may be useful to identify the recent needs of researchers in different fields pertaining mathematical research data, and we discuss several aspects of such an analysis. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Resorbable initiators for polymerizations of lactones

Numerous nontoxic (resorbable) salts were prepared from cations and anions belonging to the human metabolism, such as Na, K, Mg, Ca, Zn and Fe in combination with chloride, iodide, hydroxide, carbonate, acetate, stearate, glycolate, L‐lactate, D‐mandelate and various N‐substituted α‐amino acids. All these salts were used as initiators for polymerizations of L‐lactide in bulk at 100–180°C. Furthermore, Grignard reagents, hemin and hematin were included in this study. Zn L‐lactate was found to be the most useful initiator in terms of reactivity, maximum molecular weight of the isolated poly(L‐lactide) and its optical purity. Zn L‐lactate initiated copolymerizations of L‐lactide and glycolid or L‐lactide and ϵ‐caprolactone were also studied. Finally, first studies of the polymerization mechanism of zinc stearate and zin 2‐ethylhexanoate were performed. They suggest that zinc carboxylates combined with an alcohol as coinitiator form reactive zinc alkoxides which are the true initiators at temperatures < 150°C.