Comparing the electrical and protonic conductivity of mesoporous and nanocrystalline thin films of ceria-zirconia solid solutions

Due to the redox activity of the redox couple Ce3+/Ce4+, ceria-based solid solutions are typical mixed electronic and ionic conductors (MIECs) which are used e.g. as solid electrolytes in oxygen membranes or as electrode material in solid oxide fuel cells. CexZr1-xO2 (CZO) solid solutions not only show an increased thermal and mechanical stability compared to the corresponding binary oxides, but also exhibit an improved oxygen storage capacity making CZO a prominent material system for heterogeneous catalysis. Besides the control over composition, the defect chemistry of CZO may be optimized by nanostructuring. Here we present investigations of the electrical properties of mesoporous C0.8Z0.2O2 thin films prepared by solution phase coassembly of salt precursors with an amphiphilic diblock copolymer using an evaporation-induced self-assembly (EISA) process. The mesoporous thin films exhibit a regular pore network with a high surface to volume ratio making them an ideal model system to study the influence of surface effects on the transport properties. Structural characterization using SEM, WAXD, XRD, XPS and Raman spectroscopy reveal the high structural quality of the thin films with 24 nm diameter pores which are surrounded by a crystalline wall structure consisting of 3 to 15 nm grains. Nanocrystalline thin films were prepared using pulsed laser deposition and characterized by SEM and XRD. Using electrochemical impedance spectroscopy, the electrical properties of the mesoporous and nanocrystalline thin films were investigated in a temperature range from room temperature to 500 °C and under different oxygen partial pressures between 1 and 10-4 bar. Measurements under varying humidity show large differences between the mesoporous and nanocrystalline thin films. While a significant increase in the conductivity is observed for the nanocrystalline thin films at temperatures below 250 °C and high humidity conditions, the mesoporous samples show no contribution of protonic conductivity. As will be discussed, these results indicate that the high surface area of the mesoporous samples has either no or very little effect on the protonic transport properties in CZO. Please click Additional Files below to see the full abstract

Designing the mobile robot Kevin for a life science laboratory

Laboratories are being increasingly automated. In small laboratories individual processes can be fully automated, but this is usually not economically viable. Nevertheless, individual process steps can be performed by flexible, mobile robots to relieve the laboratory staff. As a contribution to the requirements in a life science laboratory the mobile, dextrous robot Kevin was designed by the Fraunhofer IPA research institute in Stuttgart, Germany. Kevin is a mobile service robot which is able to fulfill non-value adding activities such as transportation of labware. This paper gives an overview of Kevin's functionalities, its development process, and presents a preliminary study on how its lights and sounds improve user interaction

Ökologie und Religionen. Eine religionswissenschaftliche Darstellung

Erst in den letzten zwei Jahrzehnten hat sich im Westen allgemein die Erkenntnis durchgesetzt, daß Natur nicht nur beherrscht, sondern auch geschützt werden muß. Die allgemeine Relevanz des ökologischen Diskurses konnte auch von den religiösen Gemeinschaften nicht ignoriert werden, weil dieser Diskurs eine ethische Komponente enthält, die traditionell in ihren Zuständigkeitsbereich als ethisch normative Instanzen fällt. Der Anteil der Religionen am Diskurs selbst liegt im wesentlichen in dem Versuch, eine Art Umweltethik aus der eigenen Denktradition bzw. den normativen Schriften abzuleiten. Dabei ist zu beachten, daß bislang in keiner der uns bekannten Religionen der Umweltschutz im heutigen Sinne explizit thematisiert wurde, von den mahnenden Stimmen Einzelner abgesehen , da das Problembewußtsein gegenüber ökologischen Fragestellungen überhaupt erst sehr jung ist. Bei der Betrachtung des Verhältnisses der Religionen zu Umwelt und Natur muß man zwei grundlegende Aspekte unterscheiden, nämlich erstens die theoretische Interpretation und Würdigung der Natur und der Position des Menschen darin bzw. ihr gegenüber und zweitens den praktischen Umgang der konkreten Angehörigen einer religiösen Tradition mit der Natur. Es geht also um Weltverständnis und Weltverhalten und die Beziehung zwischen beiden

Mass spectrometric fragmentation patterns discriminate C1- and C4-oxidised cello-oligosaccharides from their non-oxidised and reduced forms

Lytic polysaccharide monooxygenases (LPMOs) are powerful enzymes that degrade recalcitrant polysaccharides, such as cellulose. However, the identification of LPMO-generated C1- and/or C4-oxidised oligosaccharides is far from straightforward. In particular, their fragmentation patterns have not been well established when using mass spectrometry. Hence, we studied the fragmentation behaviours of non-, C1- and C4-oxidised cello-oligosaccharides, including their sodium borodeuteride-reduced forms, by using hydrophilic interaction chromatography and negative ion mode collision induced dissociation - mass spectrometry. Non-oxidised cello-oligosaccharides showed predominantly C- and A-type cleavages. In comparison, C4-oxidised ones underwent B-/Y- and X-cleavage close to the oxidised non-reducing end, while closer to the reducing end C-/Z- and A-fragmentation predominated. C1-oxidised cello-oligosaccharides showed extensively A-cleavage. Reduced oligosaccharides showed predominant glycosidic bond cleavage, both B-/Y- and C-/Z-, close to the non-reducing end. Our findings provide signature mass spectrometric fragmentation patterns to unambiguously elucidate the catalytic behaviour and classification of LPMOs.</p

The SOM Family: Virtual Machines for Teaching and Research

This paper introduces the SOM (Simple Object Machine) family of virtual machine (VM) implementations. Starting from a Java-based implementation, several ports of the VM to different programming languages have been developed and put to successful use in teaching at both undergraduate and graduate levels since 2006. Moreover, the VMs have been used in various research projects. We document the rationale behind each of the SOM VMs and results that have been achieved in teaching and research

Elucidating the molecular landscape of the stratum corneum

Characterization of the molecular structure of skin, especially the barrier layer, the stratum corneum, is a key research priority for generating understanding to improve diagnostics, aid pharmaceutical delivery, and prevent environmental damage. Our study uses the recently developed 3D OrbiSIMS technique to conduct in situ analysis of ex vivo human skin tissue and reveals the molecular chemistry of skin in unprecedented detail, as a result of the step change in high mass resolving power compared with previous studies. This characterization exposes the nonhomogeneity of the stratum corneum, both laterally and as a function of depth. Chemical variations relating to fundamental biological processes, such as the epidermal cholesterol sulfate cycle, are visualized using in situ analysis. We are able to resolve the debate around the chemical gradients present within the epidermis, for example, whether palmitic acid is of sebaceous origin or a true component of the stratum corneum. Through in situ depth analysis of cryogenically preserved samples, we are able to propose that it is actually a component of both surface sebum and the intrinsic lipid matrix. This approach also suggests similarity between the epidermis compounds found in human and porcine skin as a function of depth. Since porcine skin is a widely used model for permeation testing this result has clinical relevance. In addition to using this technique for endogenous species, we have used it to demonstrate the permeation of a commercially important antiaging peptide into the human stratum corneum. Due to its chemical similarity to native skin components and exceptionally low effective concentration, this information was previously unattainable

Incidence of Isolated Biliary Atresia during the COVID Lockdown in Europe: Results from a Collaborative Project by RARE-Liver

Background: Biliary atresia (BA) is a rare cholangiopathy where one of the proposed aetiological mechanisms is an infectious viral trigger. Coronavirus disease-19 (COVID) lockdown restrictions were implemented to reduce the transmission of infections. Strictness of lockdown varied across European countries. This study aimed to investigate if there was an association between strictness of lockdown and change in isolated BA (IBA) incidence in Europe. Methods: We approached European centres involved in the European Reference Network RARE-LIVER. We included IBA patients born between 2015 and June 2020. We calculated the number of IBA patients born per centre per month. The Stringency Index (SI) was used as lockdown strictness indicator. The association between percentage change of mean number of IBA patients born per month and the SI was assessed. Results: We included 412 IBA patients from thirteen different centres. The median number of patients per month did not change: 6 (1–15) pre-lockdown and 7 (6–9) during lockdown (p = 0.34). There was an inverse association between SI and percentage change in IBA (B = -0.73, p = 0.03). Median age at Kasai portoenterostomy (days) did not differ between time periods (51 (9–179) vs. 53 (19–126), p = 0.73). Conclusion: In this European study, a stricter COVID-lockdown was seemingly accompanied by a simultaneous larger decrease in the number of IBA patients born per month in the lockdown. Results should be interpreted with caution due to the assumptions and limitations of the analysis