A simple approach for describing metal-supported cyclohexaphenylene dehydrogenation: Hybrid classical/DFT metadynamics simulations

The mechanisms for the dehydrogenation reaction of cyclohexaphenylene at a copper surface are investigated with the help of density functional theory and metadynamics. Our results represent a showcase for an approach that describes the surface using many-body classical potentials and molecule-surface interactions with a van der Waals model. Starting from the experimental observation that dispersion-assisted mechanisms are at least as important as catalytic processes for the description of the reaction, we fully describe the former, we identify intermediate states and estimate the free energy barriers that characterize the reactio

Characterization of progenitor domains in the developing mouse thalamus

To understand the molecular basis of the specification of thalamic nuclei, we analyzed the expression patterns of various transcription factors and defined progenitor cell populations in the embryonic mouse thalamus. We show that the basic helix-loop-helix (bHLH) transcription factor Olig3 is expressed in the entire thalamic ventricular zone and the zona limitans intrathalamica (ZLI). Next, we define two distinct progenitor domains within the thalamus, which we name pTH-R and pTH-C, located caudal to the ZLI. pTH-R is immediately caudal to the ZLI and expresses Nkx2.2, Mash1, and Olig3. pTH-C is caudal to pTH-R and expresses Ngn1, Ngn2, and Olig3. Short-term lineage analysis of Olig3-, Mash1-, Ngn1-, and Ngn2-expressing progenitor cells as well as tracing the Pitx2 cell lineage suggests that pTH-C is the only major source of thalamic nuclei containing neurons that project to the cerebral cortex, whereas pTH-R and ZLI are likely to produce distinct postmitotic populations outside of the cortex-projecting part of the thalamus. To determine if pTH-C is composed of subdomains, we characterized expression of the homeodomain protein Dbx1 and the bHLH protein Olig2. We show that Dbx1 is expressed in caudodorsal-high to rostroventral-low gradient within pTH-C. Analysis of heterozygous Dbx1 nlslacZ knockin mice demonstrated that Dbx1-expressing progenitors preferentially give rise to caudodorsal thalamic nuclei. Olig2 is expressed in an opposite gradient within pTH-C to that of Dbx1. These results establish the molecular heterogeneity within the progenitor cells of the thalamus, and suggest that such heterogeneity contributes to the specification of thalamic nuclei. J. Comp. Neurol. 505:73–91, 2007. © 2007 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56116/1/21467_ftp.pd

Reciprocal Interactions of Pit1 and GATA2 Mediate Signaling Gradient–Induced Determination of Pituitary Cell Types

AbstractThe mechanisms by which transient gradients of signaling molecules lead to emergence of specific cell types remain a central question in mammalian organogenesis. Here, we demonstrate that the appearance of four ventral pituitary cell types is mediated via the reciprocal interactions of two transcription factors, Pit1 and GATA2, which are epistatic to the remainder of the cell type–specific transcription programs and serve as the molecular memory of the transient signaling events. Unexpectedly, this program includes a DNA binding–independent function of Pit1, suppressing the ventral GATA2-dependent gonadotrope program by inhibiting GATA2 binding to gonadotrope- but not thyrotrope-specific genes, indicating that both DNA binding–dependent and –independent actions of abundant determining factors contribute to generate distinct cell phenotypes

A Nonzero Gap Two-Dimensional Carbon Allotrope from Porous Graphene

Graphene is considered one of the most promising materials for future electronic. However, in its pristine form graphene is a gapless material, which imposes limitations to its use in some electronic applications. In order to solve this problem many approaches have been tried, such as, physical and chemical functionalizations. These processes compromise some of the desirable graphene properties. In this work, based on ab initio quantum molecular dynamics, we showed that a two-dimensional carbon allotrope, named biphenylene carbon (BPC) can be obtained from selective dehydrogenation of porous graphene. BPC presents a nonzero bandgap and well-delocalized frontier orbitals. Synthetic routes to BPC are also addressed.Comment: Published on J. Phys. Chem. C, 2012, 116 (23), pp 12810-1281

Screening for affective dysregulation in school-aged children: relationship with comprehensive measures of affective dysregulation and related mental disorders

Affective dysregulation (AD) is characterized by irritability, severe temper outbursts, anger, and unpredictable mood swings, and is typically classified as a transdiagnostic entity. A reliable and valid measure is needed to adequately identify children at risk of AD. This study sought to validate a parent-rated screening questionnaire, which is part of the comprehensive Diagnostic Tool for Affective Dysregulation in Children (DADYS-Screen), by analyzing relationships with comprehensive measures of AD and related mental disorders in a community sample of children with and without AD. The sample comprised 1114 children aged 8–12 years and their parents. We used clinical, parent, and child ratings for our analyses. Across all raters, the DADYS-Screen showed large correlations with comprehensive measures of AD. As expected, correlations were stronger for measures of externalizing symptoms than for measures of internalizing symptoms. Moreover, we found negative associations with emotion regulation strategies and health-related quality of life. In receiver operating characteristic (ROC) analyses, the DADYS-Screen adequately identified children with AD and provided an optimal cut-off. We conclude that the DADYS-Screen appears to be a reliable and valid measure to identify school-aged children at risk of AD

High resolution in situ magneto-optic Kerr effect and scanning tunneling microscopy setup with all optical components in UHV

A surface magneto-optic Kerr effect (MOKE) setup fully integrated in an ultrahigh vacuum chamber is presented. The system has been designed to combine in situ MOKE and scanning tunneling microscopy. Magnetic fields up to 0.3 T can be applied at any angle in the transverse plane allowing the study of in-plane and out-of-plane magnetization. The setup performance is demonstrated for a continuous film of 0.9 monolayers (ML) Co/Rh(111) with in-plane easy axis and for a superlattice of nanometric double layer Co islands on Au(11,12,12) with out-of-plane easy axis. For Co/Au(11,12,12) we demonstrate that the magnetic anisotropy energies deduced from thermally induced magnetization reversal and from applying a torque onto the magnetization by turning the field are the same. For the presented setup we establish a coverage detection limit of 0.5 ML for transverse and 0.1 ML for polar MOKE. For island superlattices with the density of Co/Au(11,12,12), the latter limit corresponds to islands composed of about 50 atoms. The detection limit can be further reduced when optimizing the MOKE setup for either one of the two Kerr configurations. ©2009 American Institute of Physic

Impact of the COVID-19 pandemic on children with and without affective dysregulation and their families

Analyzing COVID-19-related stress in children with affective dysregulation (AD) seems especially interesting, as these children typically show heightened reactivity to potential stressors and an increased use of maladaptive emotion regulation strategies. Children in out-of-home care often show similar characteristics to those with AD. Since COVID-19 has led to interruptions in psychotherapy for children with mental health problems and to potentially reduced resources to implement treatment strategies in daily life in families or in out-of-home care, these children might show a particularly strong increase in stress levels. In this study, 512 families of children without AD and 269 families of children with AD reported on COVID-19-related stress. The sample comprised screened community, clinical, and out-of-home care samples. Sociodemographic factors, characteristics of child and caregiver before the pandemic, and perceived change in external conditions due to the pandemic were examined as potential risk or protective factors. Interestingly, only small differences emerged between families of children with and without AD or between subsamples: families of children with AD and families in out-of-home care were affected slightly more, but in few domains. Improvements and deteriorations in treatment-related effects balanced each other out. Overall, the most stable and strongest risk factor for COVID-19-related stress was perceived negative change in external conditions—particularly family conditions and leisure options. Additionally, caregiver characteristics emerged as risk factors across most models. Actions to support families during the pandemic should, therefore, facilitate external conditions and focus on caregiver characteristic to reduce familial COVID-19-related stress. Trial registration: German Clinical Trials Register (DRKS), ADOPT Online: DRKS00014963 registered 27 June 2018, ADOPT Treatment: DRKS00013317 registered 27 September 2018, ADOPT Institution: DRKS00014581 registered 04 July 2018

WDR11-mediated Hedgehog signalling defects underlie a new ciliopathy related to Kallmann syndrome

WDR11 has been implicated in congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS), human developmental genetic disorders defined by delayed puberty and infertility. However, WDR11's role in development is poorly understood. Here, we report that WDR11 modulates the Hedgehog (Hh) signalling pathway and is essential for ciliogenesis. Disruption of WDR11 expression in mouse and zebrafish results in phenotypic characteristics associated with defective Hh signalling, accompanied by dysgenesis of ciliated tissues. Wdr11-null mice also exhibit early-onset obesity. We find that WDR11 shuttles from the cilium to the nucleus in response to Hh signalling. WDR11 regulates the proteolytic processing of GLI3 and cooperates with the transcription factor EMX1 in the induction of downstream Hh pathway gene expression and gonadotrophin-releasing hormone production. The CHH/KS-associated human mutations result in loss of function of WDR11. Treatment with the Hh agonist purmorphamine partially rescues the WDR11 haploinsufficiency phenotypes. Our study reveals a novel class of ciliopathy caused by WDR11 mutations and suggests that CHH/KS may be a part of the human ciliopathy spectrum.Peer reviewe

Supporting self-regulated learning

Self-regulated learning (SRL) competences are crucial for lifelong learning. Their cultivation requires the right balance between freedom and guidance during the learning processes. Current learning systems and approaches, such as personal learning environments, give overwhelming freedom, but also let weak learners alone. Other systems, such as learning management systems or adaptive systems, tend to institutionalise learners too much, which does not support the development of SRL competences. This chapter presents possibilities and approaches to support SRL by the use of technology. After discussing the theoretical background of SRL and related technologies, a formal framework is presented that describes the SRL process, related competences, and guidelines. Furthermore, a variety of methods is presented, how learners can be supported to learn in a self-regulated way