Xenon Suboxides Stable under Pressure

We present results from first-principles calculations on solid xenon–oxygen compounds under pressure. We find that the xenon suboxide Xe₃O₂ is the first compound to become more stable than the elements, at around <i>P</i> = 75 GPa. Other, even more xenon-rich compounds follow at higher pressures, while no region of enthalpic stability is found for the monoxide XeO. We establish the spectroscopic fingerprints of a variety of structural candidates for a recently synthesized xenon–oxygen compound at atmospheric pressure and, on the basis of the proposed stoichiometry XeO₂, suggest an orthorhombic structure that comprises extended sheets of square-planar-coordinated xenon atoms connected through bent Xe–O–Xe linkages

Human TDP-43 and FUS selectively affect motor neuron maturation and survival in a murine cell model of ALS by non-cell-autonomous mechanisms

<p>TAR DNA-binding protein 43 (TDP-43) and fused in sarcoma (FUS) were recently found to cause familial and sporadic amyotrophic lateral sclerosis (ALS). The mechanisms by which mutations within these genes cause ALS are not understood. We established murine embryonic stem cell (ESC)-based cell models that stably express the human wild-type (WT) and various ALS causing mutations of <i>TDP-43</i> (A315T) and <i>FUS</i> (R514S, R521C and P525L). We investigated their effect on pan-neuron as well as motor neuron degeneration. Finally, non-cell-autonomous mediated neurodegeneration by muscle cells was investigated. Expression of mutant hTDP-43, but not wild-type TDP-43, as well as wild-type and mutant hFUS proteins induced neuronal degeneration with partial selectivity for motor neurons. Motor neuron loss was accompanied by abnormal neurite morphology and length. In chimeric coculture experiments with control motor neurons and mutant muscle cells (as their major target cells), we detected that mutant hTDP-43 A315T as well as wild-type and hFUS P525L expression only in muscle cells is sufficient to exert degenerative effects on control motor neurons. In conclusion, our data indicate that a selective vulnerability of motor neurons expressing the pathogenic ALS-causing genes <i>TDP-43</i> and <i>FUS</i>, is, at least in part, mediated through non-cell-autonomous mechanisms.</p

Making Sense of Boron-Rich Binary Be–B Phases

There is much uncertainty in the literature about the structure of several Be–B phases between 20 and 33 atom % Be. We clarify the structural choices in this region of the phase diagram, proposing structural candidates obtained from a combination of chemical intuition and unbiased solid-state structure searches. In particular, we discuss the structural, dynamical, and electronic properties of the ground states of the BeB₂, BeB₃, and BeB₄ phases, as well as those of the complex (and superconducting) “BeB_2.75” phase. For the latter, we find the polyhedral borane cluster electron-counting approach very useful to explain its electronic structure. We can also make sense of the partial and mixed occupancies in the structure by looking at the cavities in a parent structure. A Be₂₉B₈₁ stoichiometry seems most reasonable for the ground state of this phase. The electronic structure points to a region of stability for three additional electrons per unit cell, a 1% difference in total electron count. For BeB₂, which is usually studied computationally in the AlB₂ structure type, we find several other structure types that are more stable, all essentially Zintl phases with 4-connected boron networks. New structure types are also predicted for BeB₃ and BeB₄ as well

Nucleation of Antiferromagnetically Coupled Chromium Dihalides: from Small Clusters to the Solid State

The nucleation of chromium dihalide clusters is investigated by studying clusters of the form CrnX2n (n ≤ 4, X = F, Cl, Br, and I) for different spin states and the corresponding low temperature solid-state modifications using density functional theory. Using both wave function based (coupled cluster) and density functional theory, we predict that in all cases the ground state of the CrX2 monomer is a bent 5B2 state arising from a weakly Renner−Teller distorted 5Πg state of the linear CrX2 unit. These quintet units can form antiferromagnetically coupled, two-dimensional chains with chromium being bridged by two halides and a nucleation growth pattern that resembles the structural motif found for the solid state. Deviations from this two-dimensional chain growth are only found for the trimers and tetramers of CrBr2 and CrI2, where a “triangular” three-dimensional geometry takes slight precedence over the planar ribbon motif. We find that each single CrX2 unit adds an almost constant amount of energy between 45 and 50 kcal/mol to the cluster growth. This is in accordance with the calculated sublimation energies for the solid state which gave 58 kcal/mol for CrF2, and between 41 and 46 kcal/mol for CrCl2, CrBr2, and CrI2. The large deviation of the calculated from the experimental sublimation energy for CrF2 is due to the high electronegativity of fluorine ligand, which substantially increases the ionic interactions, resulting in a much more tightly packed solid-state structure, which is not so well described by spin-broken density functional theory. In accordance with this, CrF2 shows an unusually large bulk modulus (395 kbar) compared to the heavier halides CrCl2 (82 kbar), CrBr2 (40 kbar), and CrI2 (18 kbar)

Table_1_Applied Bayesian Approaches for Research in Motor Neuron Disease.docx

Statistical evaluation of empirical data is the basis of the modern scientific method. Available tools include various hypothesis tests for specific data structures, as well as methods that are used to quantify the uncertainty of an obtained result. Statistics are pivotal, but many misconceptions arise due to their complexity and difficult-to-acquire mathematical background. Even though most studies rely on a frequentist interpretation of statistical readouts, the application of Bayesian statistics has increased due to the availability of easy-to-use software suites and an increased outreach favouring this topic in the scientific community. Bayesian statistics take our prior knowledge together with the obtained data to express a degree of belief how likely a certain event is. Bayes factor hypothesis testing (BFHT) provides a straightforward method to evaluate multiple hypotheses at the same time and provides evidence that favors the null hypothesis or alternative hypothesis. In the present perspective, we show the merits of BFHT for three different use cases, including a clinical trial, basic research as well as a single case study. Here we show that Bayesian statistics is a viable addition of a scientist's statistical toolset, which can help to interpret data.</p

From Wade–Mingos to Zintl–Klemm at 100 GPa: Binary Compounds of Boron and Lithium

Structural diversity and a variety of bonding schemes emerge as characteristics of the Li–B phase diagram in this ground-state theoretical investigation. We studied stoichiometries ranging from LiB₁₅ to Li₅B, over a pressure range from 1 atm to 300 GPa. At <i>P</i> = 1 atm, stability is found for the experimentally known LiB_0.8–1.0, LiB₃, and Li₃B₁₄ phases. As the pressure rises, the latter two structures are no longer even metastable, while the LiB_0.8–1.0 structures change in geometry and narrow their range of off-stoichiometry, eventually coming at high pressure to a diamondoid NaTl-type LiB. This phase then dominates the convex hull of stability. Other phases emerge as stable points at some pressure: LiB₄, Li₃B₂, Li₂B, and Li₅B. At the boron-rich end, one obtains structures expectedly containing polyhedral motifs, and geometries are governed by Wade–Mingos electron counts; LiB₄ has a BaAl₄ structure. In the center and on the lithium-rich side of the phase diagram, Zintl-phase considerations, i.e., bonding between B^<i>n</i>– entities, give us insight into the structurestetrahedral B^– networks in LiB; B pairs to isolated bonds in Li₅B

raw movie data

ZIP-compressed hierarchical folder tree containing raw movie data as 16 bit TIFF image stack files. Each movie was acquired by fluorescence video microscopy on compartmentalized motor neurons cultured in Xona microfluidic chambers at standardized distal and proximal axonal readout positions at 3 frames per second with Lysotracker and Mitotracker. For more details refer to Methods, section ‘Live imaging of MN in MFCs’. The file path of the hierarchical folder tree defines the metadata of each movie (i.e. the experimental conditions of each movie) and serves as the base for the automated movie annotation with KNIME software, as detailed in Methods, section ‘Handling of meta data throughout the work flow’ and ‘Data mining in CSV result files and assembly of final EXCEL result tables with KNIME'

FIJI Morphology macro

FIJI macro code (ijm file) of static organelle morphology analysis as described in Methods, section 'Automated object recognition and static morphology analysis with the FIJI Morphology macro'

Z-scores

MS Excel table containing Z-scores of all parameters to build the multiparametric phenotypic signatures as described in the main manuscript under Methods, section 'Assembly of phenotypic HC signatures'

Default KNIME workflow

ZIP-compressed default KNIME workflow for automated movie annotation, parameter extraction and result table assemby as detailed in Methods, section 'Data mining in CSV result files and assembly of final EXCEL result tables with KNIME'