1,023 research outputs found
Effect of fluorination on the crystal and electronic structure of organometallic cyclopentadienyl-phenylenediamino-cobalt complexes
The fluorinated half sandwich complex [CpCoLF] (Cp = cyclopentadiene; LF = o-perfluoro-phenylenediimine; 2F) shows a T-shaped geometry with the LF ligand coplanar with the metallocycle. The molecules are dimerized in a head-to-tail fashion and arranged in a herringbone manner in the crystal packing. The crystal structure of 2F is different from that of the corresponding hydrocarbon compound (2H). Moreover, the differences due to the presence of fluorine atoms are also highlighted by the analysis of the intermolecular contacts, which show that 2F exhibits several F⋯F contacts, as well as aromatic intra-dimer π … π interactions in addition to C–H … π and C–H⋯F contacts. No relevant π … π interactions are observed in the case of 2H. Hirshfeld Surface (HS) analysis also depicted well the differences in the solid state interactions between the different crystal structures. In particular, HS has been useful in highlighting the differences observed between the crystal structure of 2H obtained from Rietveld refinement and that measured on single crystal (2HP and 2HSCH, respectively). The effect of the fluorination on the electronic structure has been investigated also by CV measurements and Density Functional Theory calculations. Both are consistent with a lowering in energy of the molecular orbitals. Data Mining Force Field calculations clearly indicate that the 2HSCH structure is more stable than the 2HP one. These findings can be explained in terms of the energy of the intermolecular interactions. The enhanced stability of the fluorine substitute can be easily explained by the large number of strong interactions involving fluorine atoms
Cognitive conflicts in major depression : Between desired change and personal coherence
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposesThe notion of intrapsychic conflict has been present in psychopathology for more than a century within different theoretical orientations. However, internal conflicts have not received enough empirical attention, nor has their importance in depression been fully elaborated. This study is based on the notion of cognitive conflict, understood as implicative dilemma (ID), and on a new way of identifying these conflicts by means of the Repertory Grid Technique. Our aim was to explore the relevance of cognitive conflicts among depressive patientsPeer reviewedFinal Published versio
Different pathways of molecular pathophysiology underlie cognitive and motor tauopathy phenotypes in transgenic models for Alzheimer’s disease and frontotemporal lobar degeneration
Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Acknowledgments From the Berlin Laboratory, we thank Ingo Voigt for performing the injections of the two constructs into the oocytes, Bettina Seelhorst for her extensive technical assistance, Anna Thoma for taking specific care of the animals, and John Horn, Charite Core Facility for electron microscopy for performing expert analyses in ultra-cryosections with immunogold technique. Expert comments on the manuscript from Silke Frahm-Barske (Berlin) are also acknowledged. Special thanks to Bob Switzer at NeuroScience Associates Inc. for embedding, sectioning and staining mouse brains. This work was funded by TauRx Therapeutics, Singapore. C.R.H. and C.M.W. declare that they are officers in TauRx Therapeutics Ltd.Peer reviewedPublisher PD
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A triple protostar system formed via fragmentation of a gravitationally unstable disk
Binary and multiple star systems are a frequent outcome of the star formation process(1,2) and as a result almost half of all stars with masses similar to that of the Sun have at least one companion star(3). Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large-scale fragmentation of turbulent gas cores and filaments(4,5) or smaller-scale fragmentation of a massive protostellar disk due to gravitational instability(6,7). Observational evidence for turbulent fragmentation on scales of more than 1,000 astronomical units has recently emerged(8,9). Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems(10-13). The triple protostar system L1448 IRS3B is an ideal system with which to search for evidence of disk fragmentation as it is in an early phase of the star formation process, it is likely to be less than 150,000 years old(14) and all of the protostars in the system are separated by less than 200 astronomical units. Here we report observations of dust and molecular gas emission that reveal a disk with a spiral structure surrounding the three protostars. Two protostars near the centre of the disk are separated by 61 astronomical units and a tertiary protostar is coincident with a spiral arm in the outer disk at a separation of 183 astronomical units(13). The inferred mass of the central pair of protostellar objects is approximately one solar mass, while the disk surrounding the three protostars has a total mass of around 0.30 solar masses. The tertiary protostar itself has a minimum mass of about 0.085 solar masses. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150 and 320 astronomical units, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars
Potential association of LMNA-associated generalized lipodystrophy with juvenile dermatomyositis
Abstract
Background
Juvenile dermatomyositis (JDM) is an auto-immune muscle disease which presents with skin manifestations and muscle weakness. At least 10% of the patients with JDM present with acquired lipodystrophy. Laminopathies are caused by mutations in the lamin genes and cover a wide spectrum of diseases including muscular dystrophies and lipodystrophy. The p.T10I LMNA variant is associated with a phenotype of generalized lipodystrophy that has also been called atypical progeroid syndrome.
Case presentation
A previously healthy female presented with bilateral proximal lower extremity muscle weakness at age 4. She was diagnosed with JDM based on her clinical presentation, laboratory tests and magnetic resonance imaging (MRI). She had subcutaneous fat loss which started in her extremities and progressed to her whole body. At age 7, she had diabetes, hypertriglyceridemia, low leptin levels and low body fat on dual energy X-ray absorptiometry (DEXA) scan, and was diagnosed with acquired generalized lipodystrophy (AGL). Whole exome sequencing (WES) revealed a heterozygous c.29C > T; p.T10I missense pathogenic variant in LMNA, which encodes lamins A and C. Muscle biopsy confirmed JDM rather than muscular dystrophy, showing perifascicular atrophy and perivascular mononuclear cell infiltration. Immunofluroscence of skin fibroblasts confirmed nuclear atypia and fragmentation.
Conclusions
This is a unique case with p.T10I LMNA variant displaying concurrent JDM and AGL. This co-occurrence raises the intriguing possibility that LMNA, and possibly p.T10I, may have a pathogenic role in not only the occurrence of generalized lipodystrophy, but also juvenile dermatomyositis. Careful phenotypic characterization of additional patients with laminopathies as well as individuals with JDM is warranted.https://deepblue.lib.umich.edu/bitstream/2027.42/142870/1/40842_2018_Article_58.pd
Variable Scintillation Arcs of Millisecond Pulsars observed with the Large European Array for Pulsars
We present the first large sample of scintillation arcs in millisecond
pulsars, analysing 12 sources observed with the Large European Array for
Pulsars (LEAP), and the Effelsberg 100\,m telescope. We estimate the delays
from multipath propagation, measuring significant correlated changes in
scattering timescales over a 10-year timespan. Many sources show compact
concentrations of power in the secondary spectrum, which in PSRs J06130200
and J16003053 can be tracked between observations, and are consistent with
compact scattering at fixed angular positions. Other sources such as PSRs
J16431224 and J0621+1002 show diffuse, asymmetric arcs which are likely
related to phase-gradients across the scattering screen. PSR B1937+21 shows at
least three distinct screens which dominate at different times and evidence of
varying screen axes or multi-screen interactions. We model annual and orbital
arc curvature variations in PSR J06130200, providing a measurement of the
longitude of ascending node, resolving the sense of the orbital inclination,
where our best fit model is of a screen with variable axis of anisotropy over
time, corresponding to changes in the scattering of the source. Unmodeled
variations of the screen's axis of anisotropy are likely to be a limiting
factor in determining orbital parameters with scintillation, requiring careful
consideration of variable screen properties, or independent VLBI measurements.
Long-term scintillation studies such as this serve as a complementary tool to
pulsar timing, to measure a source of correlated noise for pulsar timing
arrays, solve pulsar orbits, and to understand the astrophysical origin of
scattering screens.Comment: Submitted to MNRAS, first revision. 18 pages, 16 figure
Economical, green, and safe route towards substituted lactones by anodic generation of oxycarbonyl radicals
A new electrochemical methodology has been developed for the generation of oxycarbonyl radicals under mild and green conditions from readily available hemioxalate salts. Mono‐ and multi‐functionalised γ‐butyrolactones were synthesised through exo‐cyclisation of these oxycarbonyl radicals with an alkene, followed by the sp3–sp3 capture of the newly formed carbon‐centred radical. The synthesis of functionalised valerolactone derivatives was also achieved, demonstrating the versatility of the newly developed methodology. This represents a viable synthetic route towards pharmaceutically important fragments and further demonstrates the practicality of electrosynthesis as a green and economical method to activate small organic molecules
The VLA Nascent Disk And Multiplicity (VANDAM) Survey of Perseus Protostars. Resolving the Sub-Arcsecond Binary System in NGC 1333 IRAS2A
We are conducting a Jansky VLA Ka-band (8 mm and 1 cm) and C-band (4 cm and
6.4 cm) survey of all known protostars in the Perseus Molecular Cloud,
providing resolution down to 0.06'' and 0.35" in Ka-band and
C-band, respectively. Here we present first results from this survey that
enable us to examine the source NGC 1333 IRAS2A in unprecedented detail and
resolve it into a proto-binary system separated by 0.621"0.006" (143
AU) at 8 mm, 1 cm, and 4 cm. These 2 sources (IRAS2A VLA1 and VLA2) are likely
driving the two orthogonal outflows known to originate from IRAS2A. The
brighter source IRAS2A VLA1 is extended perpendicular to its outflow in the VLA
data, with a deconvolved size of 0.055" (13 AU), possibly tracing a
protostellar disk. The recently reported candidate companions (IRAS2A MM2 and
MM3) are not detected in either our VLA data, CARMA 1.3 mm data, or SMA 850
m data. SMA CO (), CARMA CO (), and
lower resolution CARMA CO () observations are used to examine
the outflow origins and the nature of the candidate companions to IRAS2A VLA1.
The CO () and () data show that IRAS2A MM2 is
coincident with a bright CO emission spot in the east-west outflow, and IRAS2A
MM3 is within the north-south outflow. In contrast, IRAS2A VLA2 lies at the
east-west outflow symmetry point. We propose that IRAS2A VLA2 is the driving
source of the East-West outflow and a true companion to IRAS2A VLA1, whereas
IRAS2A MM2 and MM3 may not be protostellar.Comment: Accepted to ApJ, 27 pages, 6 Figures, 2 Table
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