Perspective and limitations of cryo-electron microscopy

We investigated the possibility of vitrifying temperature-sensitive lipid phases as well as (small) biological specimens. From a suspension of unilamellar vesicles, prepared from dipalmitoyl-phosphatidylcholine (DPPC), thin aqueous films were formed at various temperatures. With cryo-electron microscopy vesicles were found to be smooth, rippled and faceted or faceted only, depending on the temperature of thin-film formation (318, 312 and 296 K respectively). The morphology and the electron diffraction patterns indicate that membranes can by physically fixed by vitrification in their high-temperature configuration and studied at low temperature by cryo-electron microscopy. This finding suggests that it may also be possible to preserve, in their original state, the more complex membrane systems found in living organisms by initiating rapid-cooling at a physiological temperature. This was explored by vitrification of thin films formed on specimen grids with (human) blood platelets adhering to collagen fibres. Low-temperature observation with an acceleration voltage of 120 kV revealed subcellular details. More details were observed when using higher accelerating voltages (200 and 300 kV) of the electron beam. The results presented in this paper illustrate the great potential of cryo-electron microscopy in the study of membrane dynamics, both in relatively simple model membrane systems and in more complex biological membrane systems.     

Glassomer—Processing Fused Silica Glass Like a Polymer

Fused silica glass is one of the most important high‐performance materials for scientific research, industry, and society. However due to its high chemical and thermal resistance as well as high hardness, fused silica glass is notoriously difficult to structure. This work introduces Glassomer, a solid nanocomposite, which can be structured using polymer molding and subtractive technologies at submicrometer resolution. After polymer processing Glassomer is turned into optical grade fused silica glass during a final heat treatment. The resulting glass has the same optical transparency as commercial fused silica and a smooth surface with a roughness of a few nanometers. This work makes high‐performance fused silica glass components accessible to high‐throughput fabrication technologies and will enable numerous optical, photonic and medical applications in science and industry.     

How to be a gamer! Exploring personal and social indicators of gamer identity

Over the past decades, digital games have continued to extend their audience as they moved into the cultural mainstream. Despite this fact, however, only a portion of those who play games consider themselves a gamer. Drawing on insights from social identity theory, this study explores the factors that contribute to why people attribute a gamer identity to self or others. It does so by considering 2 sites of identity construction: the social context of players and the broader cultural milieu. Results suggest that a gamer identity is first and foremost associated with stereotypical behaviors that find their origin in a consumption logic. Friendship networks, however, provide an important environment in which a gamer identity can be performed.     

Miniaturized octupole cytometry for cell type independent trapping and analysis

Microflow cytometry, including robust alignment, separation, and trapping of living cells, is on the verge of commercialization. Yet, the necessary equipment is frequently not applicable to certain biological questions as the products have been specifically developed for particular cell types. We present a versatile cell handling technology based on single miniaturized octupoles that enables the physical manipulation of a broad variety of different cell types via controlled negative dielectrophoresis force fields. The octupole technology allows contactless and time-resolved cell analysis in physicochemical controlled microenvironments. Contactless cell manipulation and trapping with the octupole technology were shown to be independent of cell size and morphology. This was demonstrated with nine different cell types of technical and medical relevance, ranging from motile bacteria over yeast and small platelets (thrombocytes) up to large cancer cells. We also demonstrate applications of octupole cytometry for controlled analyses of mechano-elastic properties of single cells, contactless cultivation and perfusion for perturbation studies, as well as studying the interaction of different cell types in physical proximity. These examples prove the miniaturized octupole format as a versatile, noninvasive, and robust tool for microfluidic single cell cytometry that complements existing hydrodynamic, optical, and acoustic technologies.     

Design of a flow-controlled asymmetric droplet splitter using computational fluid dynamics

In this work the design of a segmented flow microfluidic device is presented that allows droplet splitting ratios from 1:1 up to 20:1. This ratio can be dynamically changed on chip by altering an additional oil flow. The design was fabricated in PDMS chips using the standard SU-8 mold technique and does not require any valves, membranes, optics or electronics. To avoid a trial and error approach, fabricating and testing several designs, a computational fluid dynamics model was developed and validated for droplet formation and splitting. The model was used to choose between several variations of the splitting T-junction with the extra oil inlet, as well to predict the additional flow rate needed to split the droplets in various ratios. Experimental and simulated results were in line, suggesting the model’s suitability to optimize future designs and concepts. The resulting asymmetric droplet splitter design opens possibilities for controlled sampling and improved magnetic separation in bio-assay applications.     

Optimizing the performance of porous electrochemical cells for flue gas purification using the DOE method

The DOE model was used to improve the performance of cells for electrochemical gas purification. Three factors were chosen: the amount of graphite, the Lanthanum Strontium Manganate/Gadolinium-doped Cerium oxide weight % ratio, and the Lanthanum Strontium Manganate pre-calcination temperature (with or without Lanthanum Strontium Manganate calcinated at 1000 °C). The effects of the following physical properties were measured: porosity, pore size, shrinkage, and conductivity. The sintered tapes were also characterized with scanning electron microscopy. Graphite was added as a pore former.The work shows, that a change in a factor not only changes the performance property that one would expect, but also influence other properties.