Hospitality and the Nation in Mary Wollstonecraft’s A Short Residence in Sweden, Norway, and Denmark

In the summer of 1795, when Mary Wollstonecraft journeyed to Scandinavia, she was disillusioned with human society and the possibility of meaningful relation with others. She had recently been in Paris, where she had seen many of her moderate revolutionary friends executed under Robespierre’s Reign of Terror, and by the time of her arrival in Scandinavia her unsatisfactory relationship with Gilbert Imlay was coming to an end. The book that resulted from this journey, A Short Residence in Sweden, Norway, and Denmark, is remarkable for its critique of sovereignty and the reification of difference inherent to the construction of national borders and the drives of commercial exchange. The article argues that Wollstonecraft insists upon openness to the people and cultures she encounters through configuring epistemology as a twin process of experiential contact and sceptical inquiry. This a process that remains inherently and necessarily ethical because it resists the structures of tyranny, domination, and control, which Wollstonecraft perceives to be afflicting late-eighteenth-century Europe, whilst simultaneously allowing for a re-conception of politics and justice according to the demands both of the present and the not-yet-formalised future

Korrosion von Kulturgut aus Kupferwerkstoffen in Gegenwart von elementarem Schwefel in der Gasphase

"Schwarze Flecken" werden seit den 1970er Jahren immer wieder als Korrosionsproblem in Museen und Sammlungen thematisiert. Die vorliegende Arbeit beinhaltet die erste systematische Untersuchung der Korrosionsprozesse, welche zur Bildung von Kupfersulfiden in Form "Schwarzer Flecken" auf Kupferwerkstoffen führen. Hierbei war es erstmals möglich, die Korrosion mit typischer Morphologie im Laborexperiment reproduzierbar darzustellen. Experimente zur Stabilität der Korrosionsprodukte Chalkosin und Covellin sowie die Dokumentation und Analyse von über 300 betroffenen Objekten und Korrosionsproben liefern ergänzende Informationen. Die charakteristische Morphologie der Produkte wurde im Rahmen der Arbeit lichtmikroskopisch und rasterelektronenmikroskopisch untersucht. Analysen zur chemischen Zusammensetzung der Produkte wurden zerstörungsfrei am Raman-Mikroskop und mit Hilfe von EDX-Analysen durchgeführt. Ergänzend hierzu wurden einzelne Analysen mittels Röntgendiffraktometrie an Pulverproben durchgeführt. Die relative Luftfeuchte stellt bei der Korrosion von Kupferwerkstoffen in Gegenwart von elementarem Schwefel in der Gasphase den wesentlichen Einfluss auf die chemische Zusammensetzung der Korrosionsprodukte dar. Ein systematischer Zusammenhang zwischen der Morphologie, Farbe und chemischen Zusammensetzung der Korrosionsprodukte lässt sich eindeutig nachweisen. Die Temperatur beeinflusst hingegen lediglich die Korrosionsrate. Die Anwesenheit der Legierungspartner Zinn und Zink mit einem Anteil von 8 bzw. 10 % zeigt vergleichsweise geringfügige Auswirkungen auf die Korrosionsrate und die chemische Zusammensetzung der entstehenden Produkte. Die Anwesenheit der Korrosionsprodukte Malachit, Cuprit und Tenorit zeigt ebenfalls keinen bedeutenden Einfluss auf die Korrosion, auch sind die Produkte selbst unter den getesteten Bedingungen deutlich stabiler als Kupfer und die untersuchten Legierungen. Eine deckende Oxidschicht auf der Metalloberfläche schützt bei niedriger relativer Luftfeuchte vor Korrosion. Das Korrosionswachstum an Schwachstellen innerhalb einer Oxidschicht entspricht dem fleckigen Auftreten der Korrosion in der Praxis. Mit steigender relativer Luftfeuchte werden die Kupfersulfide Covellin und Chalkosin, welche als Korrosion in Form "Schwarzer Flecken" auftreten, zunehmend instabil. Covellin wirkt bei steigender relativer Luftfeuchte auf metallisches Kupfer in direktem Kontakt zunehmend korrosiv. Die gewonnenen Erkenntnisse ermöglichen uns ein besseres Verständnis der Korrosionsprozesse und liefern wichtige Informationen für den Umgang mit betroffenen Objekten in der restauratorischen und konservatorischen Praxis

Aggregates of diketopyrrolopyrrole dimers in solution

Dimers based on diketopyrrolopyrrole (DPP) chromophores have gained tremendous interest as an excellent material building block for organic solar cells and photodiodes. However, a counterintuitive blue-shift in their solution absorption spectra occurs with an increasing number of thiophene units bridging the DPP moieties. We allocate this to aggregates in solution, which might hinder adequate mixing in blends, leading to poor film forming quality and reduced charge generation in solution processed devices. Hence, identification of such aggregates is crucial in order to find measures for device optimisation. In this study, we present synthesis and characterisation of three pyridyl end-capped DPP dimers of different conjugation length using thiophene linkers and compare their parent monomer to evidence the behaviours of aggregates in solution. We employ conventional and temperature dependent UV–Vis spectroscopy, fluorescence and excitation-emission spectroscopy as well as TD-DFT calculations to show that such DPP dimers predominantly form aggregates in solution even at low concentrations. By disentangling the spectroscopic behaviour of both aggregated and non-aggregated species, we refute literature's explanation that the apparent blue shift in absorption arises from a reduced conjugation length due to more molecular flexibility. Instead, absorption and emission signals of non-aggregated dimers are mostly masked by their aggregated species. This work provides a tool set using common laboratory spectroscopic equipment to identify and characterise solution aggregates—information particularly important towards optimisation of organic electronics processed from solution

Specific protein antigen delivery to human Langerhans cells in intact skin

Immune modulating therapies and vaccines are in high demand, not least to the recent global spread of SARS-CoV2. To achieve efficient activation of the immune system, professional antigen presenting cells have proven to be key coordinators of such responses. Especially targeted approaches, actively directing antigens to specialized dendritic cells, promise to be more effective and accompanied by reduced payload due to less off-target effects. Although antibody and glycan-based targeting of receptors on dendritic cells have been employed, these are often expensive and time-consuming to manufacture or lack sufficient specificity. Thus, we applied a small-molecule ligand that specifically binds Langerin, a hallmark receptor on Langerhans cells, conjugated to a model protein antigen. Via microneedle injection, this construct was intradermally administered into intact human skin explants, selectively loading Langerhans cells in the epidermis. The ligand-mediated cellular uptake outpaces protein degradation resulting in intact antigen delivery. Due to the pivotal role of Langerhans cells in induction of immune responses, this approach of antigen-targeting of tissue-resident immune cells offers a novel way to deliver highly effective vaccines with minimally invasive administration

Nano-Alignment in Semiconducting Polymer Films: A Path to Achieve High Current Density and Brightness in Organic Light Emitting Transistors

Organic light emitting field effect transistors (LEFETs) integrate light emission of a diode with logic functions of a transistor into a single device architecture. This integration has the potential to provide simplified displays at low costs and access to injection lasing. However, the charge carrier mobility in LEFETs is a limiting factor in realizing high current densities along with a trade-off between brightness and efficiency. Herein, we present a technique controlling the nanoscale morphology of semiconducting polymers using nanoscale grooved substrates and dip-coating deposition to achieve high current density. We then applied this approach to heterostructure LEFETs and demonstrated brightness exceeding 29000 cd m–2 at an EQE of 0.4% for a yellow emitter and 9600 cd m–2 at an EQE of 0.7% for a blue emitter. These results represent a significant advancement in organic optoelectronics and are an important milestone toward the realization of new applications in displays and electrically pumped lasing

A Remote Secondary Binding Pocket Promotes Heteromultivalent Targeting of DC-SIGN

Dendritic cells (DC) are antigen-presenting cells coordinating the interplay of the innate and the adaptive immune response. The endocytic C-type lectin receptors DC-SIGN and Langerin display expression profiles restricted to distinct DC subtypes and have emerged as prime targets for next-generation immunotherapies and anti-infectives. Using heteromultivalent liposomes copresenting mannosides bearing aromatic aglycones with natural glycan ligands, we serendipitously discovered striking cooperativity effects for DC-SIGN+ but not for Langerin+ cell lines. Mechanistic investigations combining NMR spectroscopy with molecular docking and molecular dynamics simulations led to the identification of a secondary binding pocket for the glycomimetics. This pocket, located remotely of DC-SIGN’s carbohydrate bindings site, can be leveraged by heteromultivalent avidity enhancement. We further present preliminary evidence that the aglycone allosterically activates glycan recognition and thereby contributes to DC-SIGN-specific cell targeting. Our findings have important implications for both translational and basic glycoscience, showcasing heteromultivalent targeting of DCs to improve specificity and supporting potential allosteric regulation of DC-SIGN and CLRs in general

Automated laser-transfer synthesis of high-density microarrays for infectious disease screening

Abstract Laser-induced forward transfer (LIFT) is a rapid laser-patterning technique for high-throughput combinatorial synthesis directly on glass slides. A lack of automation and precision limited LIFT applications to simple proof-of-concept syntheses of fewer than 100 compounds. Here, we report an automated synthesis instrument that combines laser transfer and robotics for parallel synthesis in a microarray format with up to 10000 individual reactions/cm2. An optimized pipeline for amide bond formation is the basis for preparing complex peptide microarrays with thousands of different sequences in high yield with high reproducibility. The resulting peptide arrays are of higher quality than commercial peptide arrays. More than 4800 15-residue peptides resembling the entire Ebola virus proteome on a microarray were synthesized to study the antibody response of an Ebola virus infection survivor. We identified known and unknown epitopes that serve now as a basis for Ebola diagnostic development. The versatility and precision of the synthesizer is demonstrated by in situ synthesis of fluorescent molecules via Schiff base reaction and multi-step patterning of precisely definable amounts of fluorophores. This automated laser transfer synthesis approach opens new avenues for high-throughput chemical synthesis and biological screening