Physical State of the Deep Interior of the CoRoT-7b Exoplanet

The present study takes the CoRoT-7b exoplanet as an analogue for massive terrestrial planets to investigate conditions, under which intrinsic magnetic fields could be sustained in liquid cores. We examine the effect of depth-dependent transport parameters (e.g., activation volume of mantle rock) on a planet's thermal structure and the related heat flux across the core mantle boundary. For terrestrial planets more massive than the Earth, our calculations suggest that a substantial part of the lowermost mantle is in a sluggish convective regime, primarily due to pressure effects on viscosity. Hence, we find substantially higher core temperatures than previously reported from parameterized convection models. We also discuss the effect of melting point depression in the presence of impurities (e.g., sulfur) in iron-rich cores and compare corresponding melting relations to the calculated thermal structure. Since impurity effects become less important at the elevated pressure and temperature conditions prevalent in the deep interior of CoRoT-7b, iron-rich cores are likely solid, implying that a self-sustained magnetic field would be absent.Comment: 4 pages, 3 figures. IAU 276 Proceeding

Cancer-associated TERT promoter mutations abrogate telomerase silencing.

Mutations in the human telomerase reverse transcriptase (TERT) promoter are the most frequent non-coding mutations in cancer, but their molecular mechanism in tumorigenesis has not been established. We used genome editing of human pluripotent stem cells with physiological telomerase expression to elucidate the mechanism by which these mutations contribute to human disease. Surprisingly, telomerase-expressing embryonic stem cells engineered to carry any of the three most frequent TERT promoter mutations showed only a modest increase in TERT transcription with no impact on telomerase activity. However, upon differentiation into somatic cells, which normally silence telomerase, cells with TERT promoter mutations failed to silence TERT expression, resulting in increased telomerase activity and aberrantly long telomeres. Thus, TERT promoter mutations are sufficient to overcome the proliferative barrier imposed by telomere shortening without additional tumor-selected mutations. These data establish that TERT promoter mutations can promote immortalization and tumorigenesis of incipient cancer cells

Structural investigation and strain analysis of a polyphase flower structure in the Lower Saxony Basin, Germany

The Lower Saxony Basin (LSB) is a part of the post-Variscan Central European Basin System. We used a 3-D reflection seismic dataset in the northern LSB, provided by RWE-DEA AG, Hamburg (c.f. Lohr et al. submitted) for our investigation, which is concerned with the detailed structural and kinematic analysis of a flower structure within Mesozoic strata. This data is used in turn to determine input parameters for further 3-D geometrical retro-deformation. The retro-deformation verifies our assumptions about the structure and tectonic processes, and gives further information about sub-seismic strain distribution with respect to the branch faults of the flower structure.conferenc

Characterisation of FUT4 and FUT6 α-(1 → 2)-fucosyltransferases reveals that absence of root arabinogalactan fucosylation increases Arabidopsis root growth salt sensitivity.

Plant type II arabinogalactan (AG) polysaccharides are attached to arabinogalactan proteins (AGPs) at hydroxyproline residues, and they are very diverse and heterogeneous structures. The AG consists of a β-(1 → 3)-linked galactan backbone with β-(1 → 6)-galactan side chains that are modified mainly with arabinose, but they may also contain glucuronic acid, rhamnose or other sugars. Here, we studied the positions of fucose substitutions in AGPs, and we investigated the functions of this fucosylation. Monosaccharide analysis of Arabidopsis leaf AGP extracts revealed a significant reduction in L-Fucose content in the fut4 mutant, but not in the fut6 mutant. In addition, Fucose was reduced in the fut4 mutant in root AGP extracts and was absent in the fut4/fut6 mutant. Curiously, in all cases reduction of fucose was accompanied with a reduction in xylose levels. The fucosylated AGP structures in leaves and roots in wild type and fut mutant plants were characterised by sequential digestion with AG specific enzymes, analysis by Polysaccharide Analysis using Carbohydrate gel Electrophoresis, and Matrix Assisted Laser Desorption/Ionisation (MALDI)-Time of Flight Mass spectrometry (MS). We found that FUT4 is solely responsible for the fucosylation of AGPs in leaves. The Arabidopsis thaliana FUT4 and FUT6 genes have been previously proposed to be non-redundant AG-specific fucosyltransferases. Unexpectedly, FUT4 and FUT6 enzymes both fucosylate the same AGP structures in roots, suggesting partial redundancy to each other. Detailed structural characterisation of root AGPs with high energy MALDI-Collision Induced Dissociation MS and NMR revealed an abundant unique AG oligosaccharide structure consisting of terminal xylose attached to fucose. The loss of this structure in fut4/fut6 mutants explains the reduction of both fucose and xylose in AGP extracts. Under salt-stress growth conditions the fut4/fut6 mutant lacking AGP fucosylation exhibited a shorter root phenotype than wild type plants, implicating fucosylation of AGPs in maintaining proper cell expansion under these conditions

Increased Expression of Cell-Cell Signaling Genes by Stimulated Mononuclear Leukocytes in Patients with Previous Atherothrombotic Stroke A Whole Genome Expression Profile Study

Background/Aims: Inflammation plays an important role in atherosclerosis and stroke. Acute infections are recognized as trigger factors for ischemic stroke. Methods: In this whole genome expression profile study of 15 patients and 15 control subjects, we tested the hypothesis that patients with a history of atherothrombotic stroke show enhanced transcription of inflammatory genes in circulating leukocytes. RNA from unstimulated or lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) was analyzed with Affymetrix U133A GeneChips using a pooling design. Expression of single genes and functional groups of genes was analyzed by global statistical tests. Results: A total of 10,197 probe sets showed positive calls. After correction for multiple testing no single probe set revealed significant differences either without or with LPS stimulation. However, significant global expression differences were found upon LPS stimulation for the group of genes that are involved in cell-cell signaling. Conclusion: LPS stimulation of PBMCs, a condition mimicking bacterial infection, induces differential expression of a group of cell-cell signaling genes in patients with previous atherothrombotic stroke. This finding can be caused by genetic differences between both groups, but acquired risk factors, medication and technical factors may also have contributed to the result. Copyright (C) 2009 S. Karger AG, Base

Wang Xiaotong on Right Triangles: Six Problems from ‘Continuation of Ancient Mathematics’ (Seventh Century AD)

Wang Xiaotong’s 王孝通 Jigu suanjing 緝古算經 is primarily concerned with problems in solid and plane geometry leading to polynomial equa­tions which are to be solved numerically using a procedure similar to Horner’s Method. We translate and analyze here six problems in plane geometry. In each case the solution is derived using a dissection of a 3-dimensional object. We suggest an interpretation of one fragmentary comment which at first sight appears to refer to a dissection of a 4-dimensional object

Psychopathologie und elterlicher Stress bei 3- bis 6-jährigen Kindern mit Ausscheidungsstörungen

Objective: Incontinence and functional gastrointestinal disorders are common in young children and are associated with higher rates of psychological symptoms and mental disorders. This article focuses on the mutual association between incontinence and related toilet refusal syndrome, parental stress, and children’s psychopathology especially in young children. Methods: Children’s psychological symptoms, mental disorders, and parental stress levels were assessed in 38 parent-child dyads involving children with incontinence and 42 dyads of typically developing (TD) children. Results: Compared to TD children, patients had higher internalizing and externalizing CBCL scores and higher rates of clinically relevant externalizing problems. However, the rates of clinically relevant internalizing problems and mental disorders did not differ. The parents of children with incontinence reported signifi cantly higher stress levels regarding child-related stress factors (PSI-CD) than did parents of TD children. However, there were no clinically relevant parental stress scores on a group level, which remained below the clinical range (T-value < 60). When simultaneously analyzed, children’s (comorbid) mental disorders but not incontinence had a major impact on parental stress. Conclusions: Despite moderate stress levels, incontinence symptoms, urinary and fecal incontinence are highly prevalent in young children. However, stress among parents of young children was mainly elicited by any (comorbid) mental disorder.Fragestellung: Ausscheidungsstörungen (AS) wie funktionelle Harn- und Stuhlinkontinenz sind sehr häufi ge Störungen im Vorschulalter und sind mit einer erhöhten Prävalenz von psychopathologischen Symptomen und psychischen Störungen bei den betroffenen Kindern assoziiert. Innerhalb der vorliegenden Arbeit wird der wechselseitige Zusammenhang von funktioneller Harn- und Stuhlinkontinenz sowie dem damit in Verbindung stehenden Toilettenverweigerungssyndrom auf die kindliche Psychopathologie und das elterliche Stresserleben speziell bei jungen Kindern untersucht. Methode: Psychopathologische Symptome, psychische Störungen und elterliche Stressbelastung wurden in 38 Eltern-Kind-Dyaden bei Kindern mit vorhandener AS und in 42 Dyaden bei Kindern ohne AS untersucht. Ergebnisse: Kinder mit AS wiesen höhere Werte von internalisierendem und externalisierendem Problemverhalten auf und waren häufi ger von klinisch relevanter externalisierender Symptomatik betroffen. Nichtsdestotrotz war die Prävalenz psychischer Störungen vergleichbar. Eltern von Kindern mit AS berichteten signifi kant höhere kindbezogene Stresslevel. Dennoch zeigte sich auf Gruppenebene kein klinisch bedeutsamer elterlicher Stress und die mittleren Stresslevel lagen unterhalb des Bereichs der klinischen Auffälligkeit (T-Wert < 60). Bei gleichzeitiger Betrachtung des Einfl usses von AS und psychischen Störungen zeigten sich letztere als ausschlaggebend für den elterlichen Stress. Schlussfolgerungen: Trotz moderater Stresslevel konnte eine generell hohe Prävalenz von AS Symptomen bei 3–6-Jährigen aufgezeigt werden. Elterlicher Stress war jedoch bedeutsamer mit einer (komorbiden) psychischen Erkrankung assoziiert

SPLICS: a split green fluorescent protein-based contact site sensor for narrow and wide heterotypic organelle juxtaposition

Contact sites are discrete areas of organelle proximity that coordinate essential physiological processes across membranes, including Ca2+ signaling, lipid biosynthesis, apoptosis, and autophagy. However, tools to easily image inter-organelle proximity over a range of distances in living cells and in vivo are lacking. Here we report a split-GFP-based contact site sensor (SPLICS) engineered to fluoresce when organelles are in proximity. Two SPLICS versions efficiently measured narrow (8\u201310 nm) and wide (40\u201350 nm) juxtapositions between endoplasmic reticulum and mitochondria, documenting the existence of at least two types of contact sites in human cells. Narrow and wide ER\u2013mitochondria contact sites responded differently to starvation, ER stress, mitochondrial shape modifications, and changes in the levels of modulators of ER\u2013mitochondria juxtaposition. SPLICS detected contact sites in soma and axons of D. rerio Rohon Beard (RB) sensory neurons in vivo, extending its use to analyses of organelle juxtaposition in the whole anim

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