Nanocrystal Aerogels with Coupled or Decoupled Building Blocks

The influence of interparticle contact in nanoparticle-based aerogelnetwork structures is investigated by selectively connecting or isolating the buildingblocks inside of the network, thereby coupling and decoupling them in regards to theiroptical and electronic properties. This is achieved by tuning the synthesis sequence andexchanging the point of shell growth and the point of particle assembly, leading to twodistinctly different structures as examined by electron microscopy. By thoroughexamination of the resulting optical properties of the generated structures, the clearcorrelation between nanoscopic/microscopic structure and macroscopic optical proper-ties is demonstrated. Temperature-dependent measurements and effective massapproximation calculations support ourfindings

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three genomic nomenclature systems to all sequence data from the World Health Organization European Region available until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation, compare the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2

Characterization of Pellino2, a substrate of IRAK1 and IRAK4

AbstractInterleukin-1 (IL-1) receptor-associated kinases (IRAKs) are central components of Toll/IL-1 receptor (TIR) signaling pathways. In an attempt to discover novel signal transducers in TIR signaling, we identified human Pellino2 as an interaction partner of IRAK4. Pellino2 interacts with kinase-active as well as kinase-inactive IRAK1 and IRAK4. Furthermore, Pellino2 is one of the first substrates identified for IRAK1 and IRAK4. Functional studies using overexpression or RNAi knock-down of Pellino2 suggest a role of Pellino2 as a scaffolding protein similar to Pellino1. However, unlike Pellino1, Pellino2 does not seem to activate a specific transcription factor, but links TIR signaling to basic cellular processes

Multicrystalline, Highly Oriented Thick‐Film Silicon from Reduction of Soda‐Lime Glass

The study describes synthesis and characterization of > 10 µm thick multicrystalline (mc), highly oriented, p-doped silicon layers by aluminothermic reduction of low-cost soda-lime glass. X-ray diffraction shows a highly preferred (111)-orientation and excellent crystallinity. Low compressive stress and very good crystallinity are confirmed by the peak position and width of the Raman LO-phonon line, approaching the one of bulk single-crystalline wafer material. Due to strong bonding to the glass substrate layer, spalling is not observed. A conductive aluminum-rich oxide layer is formed underneath the silicon, serving as an electrical back-contact for electronic devices. Using secondary ion mass spectrometry very low concentrations of 1014–1015 cm−3 of impurities are found originating from the soda-lime glass with an iron content below the detection limit. Furthermore, a plateau-like, very homogenous Al concentration of ≈4 × 1018 cm−3 over a thickness of ≈10 µm is found, which corresponds to the solubility of Al in Si at the process temperature. Complete electronic activation within the plateau region is confirmed by carrier concentration measurements using electrochemical capacitance–voltage profiling and Raman spectroscopy. Hole concentrations in the range of few 1018 cm−3 are beneficial for the p-type base material of full-emitter cell mc-silicon photovoltaic devices

Clustering of CdSe/CdS Quantum Dot/Quantum Rods into Micelles Can Form Bright, Non-blinking, Stable, and Biocompatible Probes

We investigate clustered CdSe/CdS quantum dots/quantum rods, ranging from single to multiple encapsulated rods within amphiphilic diblock copolymer micelles, by time-resolved optical spectroscopy. The effect of the clustering and the cluster size on the optical properties is addressed. The clusters are bright and stable and show no blinking while retaining the fundamental optical properties of the individual quantum dots/quantum rods. Cell studies show neither unspecific uptake nor morphological changes of the cells, despite the increased sizes of the clusters

From Dots to Stripes to Sheets: Shape Control of Lead Sulfide Nanostructures

Controlling anisotropy in nanostructures is a challenging but rewarding task because confinement in one or more dimensions influences the physical and chemical properties of the items decisively. In particular, semiconducting nanostructures can be tailored to gain optimized properties to work as transistors or absorber material in solar cells. We demonstrate that the shape of colloidal lead sulfide nanostructures can be tuned from spheres to stripes to sheets by means of the precursor concentrations, the concentration of a chloroalkane coligand and the synthesis temperature. All final structures still possess at least one dimension in confinement. The structures cover all dimensionalities from 0D to 3D. Additionally, the effect of temperature on the shape and thickness of PbS nanosheets is shown and electrical transport measurements complement the findings