Digital records as relational objects–Yuk Hui’s concept of digital objects applied to archival science

The writings of Yuk Hui, bringing together both technical and philosophical insights, present a new way of dealing with the digital. The aim of this article is to assess the use of Hui’s theories on digital objects as a critical reframing, looking at the concept of digital records in particular. Two types of ontology are needed in order to understand digital objects according to Hui: (1) ontologies which relates to the technical language and hierarchies of knowledge representation, like metadata; (2) Ontology, which is a question of being-in-the-tradition of Heidegger’s phenomenology, the understanding of what it is to be in the world. Both are needed to account for the nature of the digital object. Further, digital objects are produced and constituted through their relations, which can be divided into discursive (technical and logical) and existential (the understanding of being-in-the-world) relations. Different conceptions of digital records are discussed, in order to find commonalities and possibilities in relation to Hui’s theory. The digital record as a process of becoming, information as affordance, and temporality are related to and structured through the application of Hui’s perspective. The article ends with the contribution of a possible redefinition of digital records: a digital record is constituted and concretised as material by discursive and existential relations that taken together function as a persistent representation. Hui’s theory is suggested as a set of coordinates for further thinking and a method for critical reading of digital records.

     

Long-term microfluidic glucose and lactate monitoring in hepatic cell culture

Monitoring cellular bioenergetic pathways provides the basis for a detailed understanding of the physiological state of a cell culture. Therefore, it is widely used as a tool amongst others in the field of in vitro toxicology. The resulting metabolic information allows for performing in vitro toxicology assays for assessing drug-induced toxicity. In this study, we demonstrate the value of a microsystem for the fully automated detection of drug-induced changes in cellular viability by continuous monitoring of the metabolic activity over several days. To this end, glucose consumption and lactate secretion of a hepatic tumor cell line were continuously measured using microfluidically addressed electrochemical sensors. Adapting enzyme-based electrochemical flat-plate sensors, originally designed for human whole-blood samples, to their use with cell culture medium supersedes the common manual and laborious colorimetric assays and off-line operated external measurement systems. The cells were exposed to different concentrations of the mitochondrial inhibitor rotenone and the cellular response was analyzed by detecting changes in the rates of the glucose and lactate metabolism. Thus, the system provides real-time information on drug-induced liver injury in vitro.     

Biomechanische Grundlagen des Startsprungs im Schwimmen

Starting block performance in swimming is of crucial importance in the individual competitions for the shorter swimming distances as well as for the relay events. The significance of this swim start performance will increase with the introduction of a new starting block with a longer and slightly steeper surface in conjunction with a push-off support for the feet and laterally adjustable handles. As grab starts and track starts were equally observed in international swimming competitions there are good reasons to assume that only the latter will remain the dominant starting technique. This report aims to summarize existing knowledge on the biomechanics of the swim start performed on a traditional starting block as a new starting block is introduced and new starting techniques are going to be developed. Following some introductory remarks on the assessment of the swim start performance, results will be discussed on the merit of different take-off techniques, on the entry behaviour, and on the force development profiles on the starting block. In conclusion, a tendency in favour of the rear-weighted track start was found in conjunction with a flat entry. In addition, it could be shown that an angular momentum around the transverse body axis combined with a dolphin kick (and a previously hyperextended hip joint) may provide hydrodynamic conditions to enter the water with a rather steep centre of mass trajectory. Finally, existing biomechanical knowledge will be presented on the relay start as well as on a possible change in the starting technique using the new block.     

The relative contributions of vocabulary,decoding, and phonemic awareness to word reading in English versus German

Beginning readers in shallow orthographies acquire word reading skills more quickly than in deep orthographies like English. In addition to extending this evidence base by comparing reading acquisition in English with the more transparent German, we conducted a longitudinal study and investigated whether different early reading skills made different contributions to word reading as a function of orthography. Children (n = 133) were recruited from the first year of primary school in New Zealand (age 5;8) and Germany (age 7;2) and from kindergartens in Germany (age 5;0) to provide both age- and schooling-matched samples. Parallel measures of phonemic awareness, vocabulary, decoding skill, and word reading (accuracy) were administered at two time points, 1 year apart. An advantage for orthography and school attendance existed for reading development. Vocabulary made a greater contribution to word reading in English than in German as did decoding skill. Findings underscore the relative importance of vocabulary and decoding skills for early reading in English.     

Utilizing microfluidics to synthesize polyethylene glycol microbeads for F?rster resonance energy transfer based glucose sensing

Here, we utilize microfluidic droplet technology to generate photopolymerizeable polyethylene glycol (PEG) hydrogel microbeads incorporating a fluorescence-based glucose bioassay. A microfluidic T-junction and multiphase flow of fluorescein isothiocyanate dextran, tetramethyl rhodamine isothiocyanate concanavalin A, and PEG in water were used to generate microdroplets in a continuous stream of hexadecane. The microdroplets were photopolymerized mid-stream with ultraviolet light exposure to form PEG microbeads and were collected at the outlet for further analysis. Devices were prototyped in PDMS and generated highly monodisperse 72 ± 2 μm sized microbeads (measured after transfer into aqueous phase) at a continuous flow rate between 0.04 ml/h—0.06 ml/h. Scanning electron microscopy analysis was conducted to analyze and confirm microbead integrity and surface morphology. Glucose sensing was carried out using a Förster resonance energy transfer (FRET) based assay. A proportional fluorescence intensity increase was measured within a 1–10 mM glucose concentration range. Microfluidically synthesized microbeads encapsulating sensing biomolecules offer a quick and low cost method to generate monodisperse biosensors for a variety of applications including cell cultures systems, tissue engineering, etc.