Benefits of current percolation in superconducting coated conductors

The critical currents of MOD/RABiTS and PLD/IBAD coated conductors have been measured as a function of magnetic field orientation and compared to films grown on single crystal substrates. By varying the orientation of magnetic field applied in the plane of the film, we are able to determine the extent to which current flow in each type of conductor is percolative. Standard MOD/RABiTS conductors have also been compared to samples whose grain boundaries have been doped by diffusing Ca from an overlayer. We find that undoped MOD/RABiTS tapes have a less anisotropic in-plane field dependence than PLD/IBAD tapes and that the uniformity of critical current as a function of in-plane field angle is greater for MOD/RABiTS samples doped with Ca.EPSRC US Department of Energ

Substrate-induced band gap opening in epitaxial graphene

Graphene has shown great application potentials as the host material for next generation electronic devices. However, despite its intriguing properties, one of the biggest hurdles for graphene to be useful as an electronic material is its lacking of an energy gap in the electronic spectra. This, for example, prevents the use of graphene in making transistors. Although several proposals have been made to open a gap in graphene's electronic spectra, they all require complex engineering of the graphene layer. Here we show that when graphene is epitaxially grown on the SiC substrate, a gap of ~ 0.26 is produced. This gap decreases as the sample thickness increases and eventually approaches zero when the number of layers exceeds four. We propose that the origin of this gap is the breaking of sublattice symmetry owing to the graphene-substrate interaction. We believe our results highlight a promising direction for band gap engineering of graphene.Comment: 10 pages, 4 figures; updated reference

Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study

Childhood loneliness is characterised by children’s perceived dissatisfaction with aspects of their social relationships. This 8-year prospective study investigates whether loneliness in childhood predicts depressive symptoms in adolescence, controlling for early childhood indicators of emotional problems and a sociometric measure of peer social preference. 296 children were tested in the infant years of primary school (T1 5 years of age), in the upper primary school (T2 9 years of age) and in secondary school (T3 13 years of age). At T1, children completed the loneliness assessment and sociometric interview. Their teachers completed externalisation and internalisation rating scales for each child. At T2, children completed a loneliness assessment, a measure of depressive symptoms, and the sociometric interview. At T3, children completed the depressive symptom assessment. An SEM analysis showed that depressive symptoms in early adolescence (age 13) were predicted by reports of depressive symptoms at age 8, which were themselves predicted by internalisation in the infant school (5 years). The interactive effect of loneliness at 5 and 9, indicative of prolonged loneliness in childhood, also predicted depressive symptoms at age 13. Parent and peer-related loneliness at age 5 and 9, peer acceptance variables, and duration of parent loneliness did not predict depression. Our results suggest that enduring peer-related loneliness during childhood constitutes an interpersonal stressor that predisposes children to adolescent depressive symptoms. Possible mediators are discussed

Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism.

Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells

The Mitochondrial Ca(2+) Uniporter: Structure, Function, and Pharmacology.

Mitochondrial Ca(2+) uptake is crucial for an array of cellular functions while an imbalance can elicit cell death. In this chapter, we briefly reviewed the various modes of mitochondrial Ca(2+) uptake and our current understanding of mitochondrial Ca(2+) homeostasis in regards to cell physiology and pathophysiology. Further, this chapter focuses on the molecular identities, intracellular regulators as well as the pharmacology of mitochondrial Ca(2+) uniporter complex

Performance measures for upper gastrointestinal endoscopy:A European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative

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Subgrouping the autism "spectrum": reflections on DSM-5

DSM-5 has moved autism from the level of subgroups ("apples and oranges") to the prototypical level ("fruit"). But making progress in research, and ultimately improving clinical practice, will require identifying subgroups within the autism spectrum

Mapping Dirac quasiparticles near a single Coulomb impurity on graphene

The response of Dirac fermions to a Coulomb potential is predicted to differ significantly from how non-relativistic electrons behave in traditional atomic and impurity systems. Surprisingly, many key theoretical predictions for this ultra-relativistic regime have not been tested. Graphene, a two-dimensional material in which electrons behave like massless Dirac fermions, provides a unique opportunity to test such predictions. Graphene’s response to a Coulomb potential also offers insight into important material characteristics, including graphene’s intrinsic dielectric constant, which is the primary factor determining the strength of electron–electron interactions in graphene. Here we present a direct measurement of the nanoscale response of Dirac fermions to a single Coulomb potential placed on a gated graphene device. Scanning tunnelling microscopy was used to fabricate tunable charge impurities on graphene, and to image electronic screening around them for a Q = +1|e| charge state. Electron-like and hole-like Dirac fermions were observed to respond differently to a Coulomb potential. Comparing the observed electron–hole asymmetry to theoretical simulations has allowed us to test predictions for how Dirac fermions behave near a Coulomb potential, as well as extract graphene’s intrinsic dielectric constant: ε[subscript g] = 3.0±1.0. This small value of ε[subscript g] indicates that electron–electron interactions can contribute significantly to graphene properties.United States. Office of Naval Research. Multidisciplinary University Research Initiative (Award N00014-09-1-1066)United States. Dept. of Energy. Office of Science (Contract DE-AC02-05CH11231)National Science Foundation (U.S.) (Award DMR-0906539

Criança, violência e saúde: desafios e questões atuais

This paper examines challenges and current issues involved in measuring exposure to different types of violence which are associated mental health problems in children and adolescents. Standardized measures suitable for epidemiological studies, selected based on their relevance in the current literature, are briefly described and commented. The assessment of child's exposure to violence may focus on a specific event (e.g., kidnapping), a specific context (e.g., war) or even of a certain type of exposure (e.g., intrafamilial physical violence). The assessment of child mental health after exposure to violence has traditionally focused on posttraumatic stress disorder (PTSD) - most frequently measured through non-diagnostic scales. However, other mental health reactions may be present and screening as well as diagnostic instruments which may be used to assess these reactions are also described. Two issues of emerging importance - the assessment of impairment and of traumatic grief in children - are also presented. Availability of culturally appropriate instruments is a crucial step towards proper identification of child mental health problems after exposure to violence.Este artigo examina os desafios e perspectivas atuais envolvidos na mensuração da exposição a diferentes tipos de violência e problemas de saúde mental em crianças e adolescentes. Instrumentos padronizados apropriados para estudos epidemiológicos, selecionados com base em sua relevância na literatura, são brevemente descritos e comentados. A avaliação de exposição à violência em crianças pode dizer respeito a um evento específico (como sequestro) ou um contexto específico (como guerra) ou mesmo um determinado tipo de exposição (como violência física intrafamiliar). A avaliação da saúde mental infantil após a exposição à violência tradicionalmente concentrou-se na avaliação do transtorno de estresse pós-traumático (TEPT) - freqüentemente avaliado através de escalas não-diagnósticas. Porém, outras reações psicológicas podem ocorrer e instrumentos que podem ser usados para avaliar estas reações também são descritos neste artigo. Dois tópicos de importância emergente - a avaliação de prejuízo funcional e do pesar traumático em crianças - são também apresentados. Instrumentos culturalmente apropriados são essenciais para a identificação de problemas de saúde mental em crianças após a exposição à violência.Division of Child and Adolescent PsychiatryUniversidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Departamento de PsiquiatriaUNIFESP, EPM, Depto. de PsiquiatriaSciEL

Role of genetic polymorphisms in tumour angiogenesis

Angiogenesis plays a crucial role in the development, growth and spread of solid tumours. Pro- and anti-angiogenic factors are abnormally expressed in tumours, influencing tumour angiogenesis, growth and progression. Polymorphisms in genes encoding angiogenic factors or their receptors may alter protein expression and/or activity. This article reviews the literature to determine the possible role of angiogenesis-related polymorphisms in cancer. Further research studies in this potentially crucial area of tumour biology are proposed