A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam

We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a low-energy and ultra-low-emittance electron beam travelling through short-period undulators. It delivers stable hard X-ray FEL radiation at 1-Å wavelength with pulse energies of more than 500 μJ, pulse durations of ~30 fs (root mean square) and spectral bandwidth below the per-mil level. Using special configurations, we have produced pulses shorter than 1 fs and, in a different set-up, broadband radiation with an unprecedented bandwidth of ~2%. The extremely small emittance demonstrated at SwissFEL paves the way for even more compact and affordable hard X-ray FELs, potentially boosting the number of facilities worldwide and thereby expanding the population of the scientific community that has access to X-ray FEL radiation

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

Perforated microelectrode arrays implanted in the regenerating adult central nervous system

Adult mammalian optic nerve axons are able to regenerate, when provided with the permissive environment of an autologous peripheral nerve graft, which is usually the sciatic nerve. This study demonstrates the ability of adult rat optic nerve axons to regenerate through the preformed perforations of a polyimide electrode carrier implanted at the interface between the proximal stump of the cut optic nerve and the stump of the peripheral nerve piece used for grafting. Evidence that retinal ganglion cells regenerated their axons through the perforated electrode carrier was obtained by retrograde labeling with a fluorescent dye deposited into the sciatic nerve graft beyond the nerve-carrier-nerve junction. The number of regenerating cells could be enhanced by injecting neuroprotective drugs like aurintricarboxylic acid and cortisol intravitreally. A second line of evidence was obtained by immunohistochemical staining with antibodies to neurofilament. Third, electrical activity of the regenerating nerves was recorded after stimulating the retina with a flash of light. The results suggest that a regenerating central nerve tract may serve as an experimental model to implant artificial microdevices to monitor the physiological and topographical properties of neurites passing through the device or to stimulate them, thus interfering with their potential to grow. This study reports for the first time that the optic nerve has unique properties, which aids in the realization of these goals

The suitability of infinite slit shaped pore model to describe the pores in highly porous carbon materials

The slit shaped pore model is often assumed to be the most suitable to describe the pores in micro mesoporous carbon materials. This article analyses the suitability of this assumption when pore size distribution of carbon materials is calculated applying non local density functional theory NLDFT to nitrogen adsorption isotherms. For further insight, three micro mesoporous carbide derived carbons CDC s synthesised from SiC, TiC and Mo2C, respectively, and denoted as SiC CDC, TiC CDC and Mo2C CDC, were characterized with nitrogen sorption, small angle neutron scattering SANS and Raman spectroscopy methods. Although the SANS and NLDFT with slit shaped pore model produced coinciding results for pore widths, it was found that the pores in all three carbon materials have different shapes and width to length ratios. Pores in SiC CDC can be approximated to sphere like, in TiC CDC to cylinder like and in Mo2C CDC to slit like shape. It was also suggested that the pore length may contribute significantly to the pore size distribution calculated using NLDFT model. Thus, the shape of pores in the carbon material investigated should be verified before the performance of carbon materials is explained in detail by the size and porous structure of micro mesoporous carbon material

Defined adhesion and growth of neurones on artificial structured substrates

Patterned adhesion of neurones and directed growth of neurites is the pre-requisite to establish meaningful in vitro models for the study of interactions and signalling between neurones. We have therefore studied two model systems for structured substrates. Silicon samples were microstructured by etching. Neurones adhered preferentially onto the bottom of the resulting grooves and wells. Outgrowth of neurites could be observed on adsorptive coating with polylysine and laminin. Most of the neurites did not cross the border between the plain surfaces of the silicon sample and the bottom of the grooves and wells. The second approach was to use interdigitating platinum comb electrodes. One of them was coated with laminin by electrochemical polymerisation. A strong outgrowth of axons was found, and such a surface modification appears to be suitable for the creation of neuronal patterns with effective growth of axons in vitro. (C) 2001 Elsevier Science Ltd. All rights reserved

Study of the structural curvature in Mo2C derived carbons with contrast matched small angle neutron scattering

The influence of the synthesis conditions on the formation of the porous and the graphitic structure of carbon materials was investigated on Mo2C derived carbon materials synthesized at different temperatures Tsyn from 700 to 1000 C . Contrast matched small angle neutron scattering method was used to obtain explicit information about the pore and pore wall structure of the carbons. It was found that carbons formed at lower Tsyn exhibit prevalently nano scale cylindrical geometry and an increase in Tsyn promotes the formation of slit like structures. Additionally, partial contrast matching was used, which effectively made the pore walls wider, enabled to hide the smaller pores, exposing in greater detail the geometries of larger mesopores. The geometry of larger structures e.g. pores and pore walls changes from mixed cylindrical and slit like to completely slit like with the increase of Tsyn. The observed change of the geometries, expressed by the increase in the dimensionality parameter, that increases from 1.2 to 1.8, empirically correlates with the decrease in the disorder between graphitic layers. Thus, we conclude that the cylindrical structures are caused by the curvature in graphitic layers formed at lower Tsyn lt;800

Development of a Unique Rapid Test to Detect Anti-bodies Directed Against an Extended RBD of SARS-CoV-2 Spike Protein: FH-HES Universities of Applied Sciences

Serological testing for antibodies directed against SARS-CoV-2 in patients may serve as a diagnostic tool to verify a previous infection and as surrogate for an elicited humoral immune response, ideally conferring immunity after infection or vaccination. Here, we present the recombinant expression of an extended receptor binding domain (RBD) of the SARS-CoV-2 Spike protein used as capture antigen in a unique rapid immunoassay to detect the presence of RBD binding antibodies with high sensitivity and specificity. As currently available vaccines focus on the Spike RBD as target, the developed test can also be used to monitor a successful immune response after vaccination with an RBD based vaccine