Digital research data: from analysis of existing standards to a scientific foundation for a modular metadata schema in nanosafety.

BACKGROUND: Assessing the safety of engineered nanomaterials (ENMs) is an interdisciplinary and complex process producing huge amounts of information and data. To make such data and metadata reusable for researchers, manufacturers, and regulatory authorities, there is an urgent need to record and provide this information in a structured, harmonized, and digitized way. RESULTS: This study aimed to identify appropriate description standards and quality criteria for the special use in nanosafety. There are many existing standards and guidelines designed for collecting data and metadata, ranging from regulatory guidelines to specific databases. Most of them are incomplete or not specifically designed for ENM research. However, by merging the content of several existing standards and guidelines, a basic catalogue of descriptive information and quality criteria was generated. In an iterative process, our interdisciplinary team identified deficits and added missing information into a comprehensive schema. Subsequently, this overview was externally evaluated by a panel of experts during a workshop. This whole process resulted in a minimum information table (MIT), specifying necessary minimum information to be provided along with experimental results on effects of ENMs in the biological context in a flexible and modular manner. The MIT is divided into six modules: general information, material information, biological model information, exposure information, endpoint read out information and analysis and statistics. These modules are further partitioned into module subdivisions serving to include more detailed information. A comparison with existing ontologies, which also aim to electronically collect data and metadata on nanosafety studies, showed that the newly developed MIT exhibits a higher level of detail compared to those existing schemas, making it more usable to prevent gaps in the communication of information. CONCLUSION: Implementing the requirements of the MIT into e.g., electronic lab notebooks (ELNs) would make the collection of all necessary data and metadata a daily routine and thereby would improve the reproducibility and reusability of experiments. Furthermore, this approach is particularly beneficial regarding the rapidly expanding developments and applications of novel non-animal alternative testing methods.

Synthesis of LiNH2 + LiH by reactive milling of Li3N.

The hydrogen sorption properties of Li3N under reactive milling conditions have been investigated in- and ex-situ as a function of polytype structure (alpha vs. beta), focusing on the influence of the micro-structure and/or the crystal structure upon hydrogen uptake. LiNH2 and LiH were synthesized by reactive milling of Li3N at 20 bar hydrogen pressure for 4 h. Reactive milling represents a quick and effective technique to produce LiNH2 by hydrogenation of Li3N at low hydrogen pressure and without any need for heating. As to our knowledge, we present a full hydrogenation of Li3N under the aforementioned conditions for the first time. The (de)hydrogenation and rehydrogenation behaviour of milled amides was evaluated using a combination of powder X-ray diffraction, differential scanning calorimetry, thermogravimetry and in situ Raman spectroscopy. In situ Raman spectroscopy showed a shift in the lithium amide stretching modes upon hydrogenation supporting a non-stoichiometric storage mechanism consistent with the literature. The microstructure and polytype composition of the Li3N dehydrogenated materials had no effect on the hydrogenation products and only minor effects on the hydrogen uptake profile during milling.