Die Pilotanwendung der weltweit größten künstlichen Sonne in der solarthermischen Wasserstofferzeugung im Technikumsmaßstab

In Jülich wird in den kommenden Jahren die weltweit größte künstliche Sonne gebaut. Sie wird hochkonzentrierte optische Strahlung mit einer Strahlungsleistung bis zu ca. 200 kW liefern. Das Institut für Solarforschung wird mit ihrer Hilfe neue Komponenten für solarthermische Kraftwerke entwickeln und testen. Vor allem werden in der neuen Anlage auch neue Verfahren zur Herstellung solarer Treibstoffe, insbesondere Wasserstoff, erarbeitet. Die neue Anlage wird außerdem ein wichtiges Element in der Entwicklung des Standorts Jülich zu einem Campus für die angewandte Solarforschung sein

EUropean Heliospheric FORecasting Information Asset 2.0

Aims: This paper presents a H2020 project aimed at developing an advanced space weather forecasting tool, combining the MagnetoHydroDynamic (MHD) solar wind and coronal mass ejection (CME) evolution modelling with solar energetic particle (SEP) transport and acceleration model(s). The EUHFORIA 2.0 project will address the geoeffectiveness of impacts and mitigation to avoid (part of the) damage, including that of extreme events, related to solar eruptions, solar wind streams, and SEPs, with particular emphasis on its application to forecast geomagnetically induced currents (GICs) and radiation on geospace. Methods: We will apply innovative methods and state-of-the-art numerical techniques to extend the recent heliospheric solar wind and CME propagation model EUHFORIA with two integrated key facilities that are crucial for improving its predictive power and reliability, namely (1) data-driven flux-rope CME models, and (2) physics-based, self-consistent SEP models for the acceleration and transport of particles along and across the magnetic field lines. This involves the novel coupling of advanced space weather models. In addition, after validating the upgraded EUHFORIA/SEP model, it will be coupled to existing models for GICs and atmospheric radiation transport models. This will result in a reliable prediction tool for radiation hazards from SEP events, affecting astronauts, passengers and crew in high-flying aircraft, and the impact of space weather events on power grid infrastructure, telecommunication, and navigation satellites. Finally, this innovative tool will be integrated into both the Virtual Space Weather Modeling Centre (VSWMC, ESA) and the space weather forecasting procedures at the ESA SSCC in Ukkel (Belgium), so that it will be available to the space weather community and effectively used for improved predictions and forecasts of the evolution of CME magnetic structures and their impact on Earth. Results: The results of the first six months of the EU H2020 project are presented here. These concern alternative coronal models, the application of adaptive mesh refinement techniques in the heliospheric part of EUHFORIA, alternative flux-rope CME models, evaluation of data-assimilation based on Karman filtering for the solar wind modelling, and a feasibility study of the integration of SEP models.</p

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing

Chromothripsis is a mutational phenomenon characterized by massive, clustered genomic rearrangements that occurs in cancer and other diseases. Recent studies in selected cancer types have suggested that chromothripsis may be more common than initially inferred from low-resolution copy-number data. Here, as part of the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA), we analyze patterns of chromothripsis across 2,658 tumors from 38 cancer types using whole-genome sequencing data. We find that chromothripsis events are pervasive across cancers, with a frequency of more than 50% in several cancer types. Whereas canonical chromothripsis profiles display oscillations between two copy-number states, a considerable fraction of events involve multiple chromosomes and additional structural alterations. In addition to non-homologous end joining, we detect signatures of replication-associated processes and templated insertions. Chromothripsis contributes to oncogene amplification and to inactivation of genes such as mismatch-repair-related genes. These findings show that chromothripsis is a major process that drives genome evolution in human cancer

The coordination chemistry of sterically demanding pentadienyl ligands with rare earth metals

Die Abhandlung „Untersuchungen zur Koordinationschemie sterisch anspruchsvoller Pentadienyl-Liganden gegenüber Seltenen Erden“ befasst sich mit der Anwendung des im Arbeitskreis bereits vielseitig verwendeten Pentadienyl-Liganden pdl‘ (2,4-Di-tert-butylpentadienyl) und der Übertragung des Wissens zur Synthese und Charakterisierung der d-Übergangsmetallkomplexe auf die Seltenen Erden. Diese umfassen die 4f-Elemente, sowie die Übergangsmetalle Scandium und Yttrium. Im ersten Abschnitt wurde unter Annahme von Salzmetathesereaktionen je ein Äquivalent eines geeigneten Seltenerdmetall(III)halogenids mit drei Äquivalenten Kpdl‘ umgesetzt. Dabei haben sich drei Reaktionspfade ergeben. 1. Salzmetathese: Die Seltenen Erden mit großen Ionenradius (La, Ce, Pr, Nd) bildeten Salzmetathesekomplexe des Typs [pdl‘3Ln] - 1-Ln. 2. Reduktion: Die leicht zu reduzierenden Seltenen Erden Samarium, Europium und Ytterbium bildeten auch bei Einsatz dreiwertiger Vorläuferverbindungen zweiwertige Komplexe des Typs [pdl‘2Ln(thf)n] (n = 1, 2) - 2-Ln. Als Nebenprodukt entstand dabei das Kupplungsprodukt zweier Pentadienyle: pdl‘2. Um dieses Nebenprodukt zu vermeiden, wurden in Folge stets die zweiwertigen Vorläuferverbindungen verwendet. 3. Deprotonierung: Die Seltenen Erden mit kleinen Ionenradien (Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Lu) bildeten zweikernige Komplexe des Typs [pdl‘3Ln2(thf)2] aus - 3-Ln. Die Besonderheit hier war, dass in diesen Komplexen der Ligand pdl‘ gleichzeitig in einfach, zweifach und dreifach deprotonierter Form vorlag. Sämtliche Komplexe wurden sowohl in Lösung als auch im Festkörper charakterisiert. Im zweiten Abschnitt der Arbeit wurden die Eigenschaften des Komplexes 1-La aus dem ersten Abschnitt näher beleuchtet. Dabei wurde zunächst die Realisierbarkeit der Verbindung [pdl‘2LaI(thf)] untersucht und deren Beziehung zu 1-La. Die durch teilweise Salzmetathese erzeugte reaktive Stelle, das Iodid, sollte dabei als Angriffspunkt für weitere Modifikationen dienen. In weiteren Umsetzungsschritten wurden so einige heteroleptische Lanthan(III)-Komplexe synthetisiert und charakterisiert. Die Umsetzung mit Metall-Alkylen zur Erzeugung von Lanthan-Alkyl-Komplexen hat sich dabei als besonders herausfordernd herausgestellt und ist nicht direkt gelungen. Es kann die Vermutung angestellt werden, dass entstandene Alkyl-Komplexe als Zwischenstufen fungierten, von denen ausgehend inter- oder intramolekulare Deprotonierungsreaktionen zu den Komplexen 13-La und 14-La führten. Im zweiten Teil des zweiten Abschnitts ist der Einfluss des Substitutionsmusters verschiedener Pentadienyl-Liganden auf die Umsetzung von Tris(pentadienyl)lanthan-Komplexen mit AlMe3 untersucht worden. Dabei hat sich gezeigt, dass der sterisch anspruchsvollste Ligand (pdl‘)- die mildesten Reaktionsbedingungen zur Synthese von [pdl2La(AlMe4)] benötigt und als einziger die Eliminierung von Methan zur Bildung von 18-La unter handhabbaren Bedingungen zulässt. Das dritte Kapitel befasste sich näher mit den zweiwertigen Seltenerdmetallkomplexen 2-Ln. Als Untersuchungskriterium galt das koordinierte Lösungsmittel thf. Dieses sollte durch geeignete Lewis-Basen, einen nicht-unschuldigen Liganden, NHCs und Imidazolin-2-thione (S=NHCs) ersetzt werden. Zunächst wurde die Austauschbarkeit von thf durch 4-(N,N-Dimethylamino)pyridin für die Komplexe 2-Ln (Ln = Sm, Eu, Yb) nachgewiesen. Die Umsetzung mit 2,2‘-Bipyridin ergab für die Metalle Samarium und Europium grundverschiedene Verbindungen. Ein etwas umfangreicherer Teil befasste sich mit der Umsetzung mit NHCs und S=NHCs und den daraus resultierenden Unterschieden beim Einsatz von 2-Sm und 2-Yb. Dabei konnten einige Unterschiede zwischen den eigesetzten Metallen herausgearbeitet werden.The PhD thesis “The coordination chemistry of sterically demanding pentadienyl ligands with rare earth metals“ deals with the transfer of knowledge gained in the Walter group on the sterically demanding pdl‘ ligand (2,4-di-tert-butylpentadienyl) to the field of rare earth metals. This includes the 4f elements as well as scandium and yttrium. The first chapter focusses on the reactivity of Kpdl’ with different rare earth metals. Therefore, in the beginning every rare earth metal precursor in oxidation state +III available in the group was treated with three equivalents of Kpdl’ expecting salt metathesis reactions. However, three different reaction products were identified: 1. Salt metathesis reactions. Rare earth metals with a comparably large ionic radius (La, Ce, Pr, Nd) gave the expected complexes with the general formula [pdl’3Ln] - 1-Ln. 2. Reduction products. Rare earth metals with relatively low reduction potentials (Sm, Eu, Yb) can be reduced by an excess of Kpdl’ to yield complexes of the type [pdl’2Ln(thf)n] (n = 1, 2) - 2-Ln. As a byproduct, the coupling product of two pentadienyls (pdl’2) is formed. To avoid the formation of this byproduct, which is difficult to separate from the target complex, divalent rare earth metal precursors were chosen from this point on. 3. Deprotonation complexes. Rare earth metals with a comparably small ionic radius, such as Sc, Y, Gd, Tb, Dy, Ho, Er, Tm and Lu form homobimetallic complexes of the type [pdl’3Ln2(thf)2] - 3-Ln. The key feature of these complexes is, that they contain three different forms of the pentadienyl ligand. The monoanionic form pdl’, the dianionic form (pdl’-1H)2- and the trianionic form (pdl’-2H)3- formed by inter- or intramolecular deprotonations with pdl’H as the byproduct of this reaction. All complexes were fully characterized in solution as well as in the solid state. The second chapter details the properties of 1-La. In a first step, by changing the precursor, the synthesis of [pdl’2LaI(thf)] was attempted and its relation to 1-La was examined. The incomplete salt metathesis gave rise to a labile position in the complex, the iodide. This feature was used to enable further modifications and the syntheses of new heteroleptic lanthanum complexes were targeted. One of the biggest challenges was the reaction with different metal alkyls to address lanthanum alkyl complexes. These attempts turned out unsuccessful and yielded complexes 13-La and 14-La, which might be products of an inter- or intramolecular deprotonation event involving La alkyl compounds. The second part of this chapter dealt with the influence of different substitution patterns on the pentadienyl ligand on the reaction with AlMe3. Three different substitution patterns were tested. 2,4-Dimethyl-, 2-tert-butyl-4-methyl- and 2,4-di-tert-butylpentadienyl. The sterically most demanding ligand within this series (pdl’)- has shown to need the mildest reaction conditions in order to synthesize [pdl2La(AlMe4)]. The pdl’-complex was also the only candidate enabling the elimination of methane to form 18-La in reasonable quantities. Chapter three addresses the divalent rare earth metal complexes 2-Ln. The feature of interest in this chapter was the replaceability of the coordinated solvent molecule. Attempts to replace thf with other Lewis bases, redox non-innocent ligands, NHCs and imidazoline-2-thiones (S=NHCs) were made. In the first place the possibility to exchange thf with 4-dimethylaminopyridine was proven for Sm, Eu and Yb. Reactions with 2,2’-bypiridine gave rise to two different products for Sm and Eu, respectively, while no isolable product for Yb was obtained. A more thorough investigation was made for the differences in the reaction of various NHCs and S=NHCs with 2-Sm and 2-Yb giving rise to several unusual coordination patterns

Spread of local anesthetics after erector spinae plane block: an MRI study in healthy volunteers

Background. Erector spinae plane block (ESPB) is a truncal fascial block with a disputed mechanism and anatomical site of effect. This study aimed to perform a one-sided ESPB and use MRI to investigate the spread of the local anesthetic (LA) and the corresponding cutaneous loss of sensation to pinprick and cold. Methods. Ten volunteers received a right-sided ESPB at the level of the seventh thoracic vertebra (Th7), consisting of 30mL 2.5mg/mL ropivacaine with 0.3mL gadolinium. The primary outcome was the evaluation of the spread of LA on MRI 1-hour postblock. The secondary outcome was the loss of sensation to cold and pinprick 30–50min after the block was performed. Results. All volunteers had a spread of LA on MRI in the erector spinae muscles and to the intercostal space. 9/10 had spread to the paravertebral space and 8/10 had spread to the neural foramina. 4/10 volunteers had spread to the epidural space. One volunteer had extensive epidural spread as well as contralateral epidural and foraminal spread. Four volunteers had a loss of sensation both posterior and anterior to the midaxillary line, while six volunteers had a loss of sensation only on the posterior side. Conclusion. We found that LA consistently spreads to the intercostal space, the paravertebral space, and the neural foramina after an ESPB. Epidural spread was evident in four volunteers. Sensory testing 30–50min after an ESPB shows highly variable results, and generally under-represents what could be expected from the visualized spread on MRI 60min after block performance.publishedVersio

Low-Coordinate Iron(II) Amido Half-Sandwich Complexes with Large Internal Magnetic Hyperfine Fields

The half-sandwich complex [Cp′Fe{N(dipp)(SiMe3)}] (Fe-dipp; Cp′ = 1,2,4-tri-tert-butylcyclopentadienyl and dipp = 2,6-diisopropylphenyl) and the mixed metallocene [Cp′Fe{(η5-C6H3iPr2)N(SiMe3)}] (Fe-chd) formed in the reaction between [{Cp′Fe(μ-I)}2] and [Li{N(dipp)(SiMe3)}]2 were characterized by NMR spectroscopy and X-ray diffraction analysis. Fe-dipp complements the series of low-coordinate, quasi-linear iron amido half-sandwich complexes [Cp′Fe{N(tBu)(SiMe3)}] (Fe-tBu) and [Cp′Fe{N(SiMe3)2}] (Fe-tms) reported earlier, and all three compounds were characterized in the solid state by zero-field 57Fe Mössbauer spectroscopy and magnetic susceptibility measurements, confirming their S = 2 electronic ground state. Moreover, the Mössbauer absorption spectra reveal slow paramagnetic relaxation at low temperatures with large internal magnetic hyperfine fields of Bhf = 96.4 T (Fe-dipp, 20 K), Bhf = 101.3 T (Fe-tBu, 15 K), and Bhf = 96.9 T (Fe-tms, 20 K). The magnetic measurements further confirm that the presence of significant axial zero-field splitting and slow relaxation of magnetization is detected, which is revealed even in the absence of a static magnetic field in the case of Fe-tBu. Supplementary ab initio and density functional theory calculations were performed and support the experimental data

Solares Recyceln von Aluminium in einem direkt bestrahlten Drehrohrofen

Das Aufschmelzen von Metallen ist ein energieintensiver Prozess, da hier hohe Temperaturen benötigt werden. Konventionell wird diese Energie mit fossilen Energieträgern zur Verfügung gestellt. Mit einem solaren Schmelzverfahren von Metallen können der Ausstoß von CO2 und die Energiekosten der Gießereien erheblich gesenkt werden. Insbesondere Länder mit hoher direkter Solarstrahlung wie Südafrika, können ein solches Verfahren zum Schmelzen und Wiederverwerten von Metallschrott einsetzten. Das vom BMBF geförderte Projekt SOLAM zielt auf die Entwicklung eines solaren Schmelzprozesses für Aluminium ab. Das wesentliche Projektziel ist die Entwicklung, der Aufbau und Test eines solaren Drehrohrofens zum Schmelzen und Recyceln von Aluminium