Frustrated quantum antiferromagnetism with ultracold bosons in a triangular lattice

We propose to realize the anisotropic triangular-lattice Bose-Hubbard model with positive tunneling matrix elements by using ultracold atoms in an optical lattice dressed by a fast lattice oscillation. This model exhibits frustrated antiferromagnetism at experimentally feasible temperatures; it interpolates between a classical rotor model for weak interaction, and a quantum spin-1/2 $XY$-model in the limit of hard-core bosons. This allows to explore experimentally gapped spin liquid phases predicted recently [Schmied et al., New J. Phys. {\bf 10}, 045017 (2008)].Comment: 6 pages, as published in EP

Engineering spin waves in a high-spin ultracold Fermi gas

We report on the detailed study of multi-component spin-waves in an s=3/2 Fermi gas where the high spin leads to novel tensorial degrees of freedom compared to s = 1/2 systems. The excitations of a spin-nematic state are investigated from the linear to the nonlinear regime, where the tensorial character is particularly pronounced. By tuning the initial state we engineer the tensorial spin-wave character, such that the magnitude and sign of the counterflow spin-currents are effectively controlled. A comparison of our data with numerical and analytical results shows excellent agreement.Comment: 9 pages, 4 figure

Die Zusammensetzung des Mikrobioms bei Sarkoidose

Einleitung: Sarkoidose ist eine entzündliche Systemerkrankung mit einer nicht vollständig geklärten Ätiologie. Es existieren mehrere Hypothesen über ein auslösendes Antigen, welches eine Immunreaktion initiiert. Im Vorder-grund stehen dabei mikrobielle Erreger, welche durch vorausgehende Studien als potentielle Auslöser identifiziert wurden. Durch neue Verfahren der Mikro-biomanalyse können deutlich breitere Spektren an potentiellen Erregern er-fasst werden. Ziele: Diese Arbeit vergleicht das Mikrobiom von Patienten mit Sarkoidose und dem von Patienten mit anderen interstitiellen Lungenerkrankungen und hat zum Ziel, einen mikrobiellen Auslöser der Sarkoidose zu identifizieren. Methoden: Im Rahmen der PULMOHOM Studie wurden Patienten mit Sarkoi-dose und anderen interstitiellen Lungenerkrankungen rekrutiert und einer Bronchoskopie mit bronchoalveolärer Lavage unterzogen. Wichtige klinische Patientendaten, sowie die zelluläre Zusammensetzung der bronchoalveolären Lavage (BAL) in Bezug auf die Immunzellen wurden zwischen beiden Grup-pen verglichen. Die BAL wurde durch Sequenzierung der mikrobiellen 16sRNA Gene und folgender biostatistischer Auswertung auf Unterschiede im Mikrobiom untersucht. Ergebnisse: Es zeigten sich wenige signifikante Unterschiede in der zellulä-ren Zusammensetzung der BAL zwischen beiden Gruppen. Dabei war in der Sarkoidosegruppe ein höherer CD4/CD8 Quotient, sowie ein höherer Anteil an Alveolarmakrophagen, sowie Lymphozyten vorhanden. Jedoch zeigten sich keine signifikanten Unterschiede des Mikrobioms zwischen Patienten mit Sar-koidose und anderen interstitiellen Lungenerkrankungen. Der direkte Ver-gleich verschiedener Bakterienstämme mittels Heatmap, sowie der Alpha-Diversität, Hauptkomponentenanalyse und Korrespondenzanalyse zeigte kei-nen signifikanten Unterschied. Eine Betrachtung von Mykobakterien und Propionibakterien zeigte ebenso keine signifikanten Unterschiede. Zusammenfassung: Das Mikrobiom der Sarkoidose unterscheidet sich in der vorliegenden Arbeit nicht von dem anderer interstitiellen Lungenerkrankun-gen, basierend auf einer Sequenzierung der 16sRNA Gene und einer multiva-rianten statistischen Auswertung. Hinweise auf eine Beteiligung von My-kobakterien oder Propionibakterien bei der Genese der Sarkoidose wurden nicht gesehen. Die Analysen konnten eine mikrobielle Genese der Sarkoidose nicht bekräftigen. Die aufgeführten Daten widerlegen allerdings auch nicht eine mikrobiologische Komponente in der Pathogenese der Sarkoidose. Diver-se Faktoren, zum Beispiel der Ort der Materialgewinnung, das Krankheitssta-dium oder Komorbiditäten könnten das Mikrobiom maßgeblich beeinflussen. Die vorliegenden Daten zeigen nur einen kleinen Ausschnitt des Gesamtbil-des Mikrobiom der Lunge. Gegenstand zukünftiger Studien könnte die Unter-suchung dieser Faktoren mit ihren Auswirkungen sein um eine möglichst standardisierte Herangehensweise bei Mikrobiomanalysen zu ermöglichen

Mechanochemical reactions and syntheses of oxides

Technological and scientific challenges coupled with environmental considerations have prompted a search for simple and energy-efficient syntheses and processing routes of materials. This tutorial review provides an overview of recent research efforts in non-conventional reactions and syntheses of oxides induced by mechanical action. It starts with a brief account of the history of mechanochemistry. Ensuing discussions will review the progress in homogeneous and heterogeneous mechanochemical reactions in oxides of various structures. The review demonstrates that the event of mechanically induced reactions provides novel opportunities for the non-thermal manipulation of materials and for the tailoring of their properties. © 2013 The Royal Society of Chemistry

Two α subunits and one β subunit of meprin zinc-endopeptidases are differentially expressed in the zebrafish Danio rerio

Meprins are members of the astacin family of metalloproteases expressed in epithelial tissues, intestinal leukocytes and certain cancer cells. In mammals, there are two homologous subunits, which form complex glycosylated disulfide-bonded homo- and heterooligomers. Both human meprin α and meprin β cleave several basement membrane components, suggesting a role in epithelial differentiation and cell migration. There is also evidence that meprin β is involved in immune defence owing to its capability of activating interleukin-1β and the diminished mobility of intestinal leukocytes in meprin β-knockout mice. Here we show for the first time by reverse transcription PCR, immunoblotting and immunofluorescence analyses that meprins are expressed not only in mammals, but also in the zebrafish Danio rerio. In contrast to the human, mouse and rat enzymes, zebrafish meprins are encoded by three genes, corresponding to two homologous α subunits and one β subunit. Observations at both the mRNA and protein level indicate a broad distribution of meprins in zebrafish. However, there are strikingly different expression patterns of the three subunits, which is consistent with meprin expression in mammals. Hence, D. rerio appears to be a suitable model to gain insight into the basic physiological functions of meprin metalloprotease

Characterisation of the Tensile and Metallurgical Properties of Laser Powder Bed Fusion-Produced Ti-6Al-4V ELI in the Duplex Annealed and Dry Electropolished Conditions

Metal additive manufacturing is becoming a popular manufacturing process in industries requiring geometrically complex components, part consolidation, and reductions in material waste. Metals manufactured via additive manufacturing processes such as laser powder bed fusion typically exhibit process-induced defects, material inhomogeneities, and anisotropy in terms of mechanical properties. Post-processing techniques such as heat treatments and surface finishing have been touted as approaches for improving these materials. Although various post-processing techniques have been proposed, the optimal post-processing route remains an active area of research. This research investigates Ti-6Al-4V ELI produced using laser powder bed fusion and post-processed via different routes. The materials in the stress-relieved and duplex annealed material conditions as well as dry electropolished and machined surface conditions were characterised. The duplex annealed Ti-6Al-4V ELI material showed improvements in ductility but at reduced strength when compared with the material in the stress-relieved condition. The microstructure of the duplex annealed material shows little evidence of process-induced defects and features and consists primarily of elongated and acicular α in a lamellar structure with intergranular β and exhibits uniform microhardness throughout the material. A reduced surface roughness due to surface finishing resulted in an improved reduction in area. This research highlights the effects of post-processing treatments and their ability to improve the properties of laser powder bed fusion-produced Ti-6Al-4V ELI

Highly Cooperative Photoswitching in Dihydropyrene Dimers

We present a strategy to achieve highly cooperative photoswitching, where the initial switching event greatly facilitates subsequent switching of the neighboring unit. By linking donor/acceptor substituted dihydropyrenes via suitable π-conjugated bridges, the quantum yield of the second photochemical ring-opening process could be enhanced by more than two orders of magnitude as compared to the first ring-opening. As a result, the intermediate mixed switching state is not detected during photoisomerization although it is formed during the thermal back reaction. Comparing the switching behavior of various dimers, both experimentally and computationally, helped to unravel the crucial role of the bridging moiety connecting both photochromic units. The presented dihydropyrene dimer serves as model system for longer cooperative switching chains, which, in principle, should enable efficient and directional transfer of information along a molecularly defined path. Moreover, our concept allows to enhance the photosensitivity in oligomeric and polymeric systems and materials thereof. © 2020 The Authors. Published by Wiley-VCH Gmb