526 research outputs found

    Evidence for transfer followed by breakup in 7Li + 65Cu

    Full text link
    The observation of a large cross-section for the alpha + d channel compared to breakup into the alpha + t channel from an exclusive measurement for the 7Li+65Cu system at 25 MeV is presented. A detailed analysis of the angular distribution using coupled channels Born approximation calculations has provided clear evidence that the observed alpha + d events arise from a two step process, i.e. direct transfer to the 2.186 MeV (3+) resonance in the alpha + d continuum of 6Li followed by breakup, and are not due to final state interaction effects.Comment: 12 pages, 3 figures, To be published in Phys. Letts.

    A new model for magnetoreception

    Get PDF
    Certain migratory birds can sense the earth's magnetic field. The nature of this process is not yet properly understood. Here we offer a simple explanation according to which birds literally `see' the local magnetic field: Our model relates the well-established radical pair hypothesis to the phenomenon of Haidinger's brush, a capacity to see the polarisation of light. This new picture explains recent surprising experimental data indicating long lifetimes for the radical pair. Moreover there is a clear evolutionary path toward this field sensing mechanism: it is an enhancement of a weak effect that may be present in many species.Comment: 8 pages, 5 figures, version of final published pape

    Ernährung bei angeborenen Stoffwechselerkrankungen — ein Spagat zwischen Genuss und Therapie

    Get PDF
    For many inborn metabolic diseases, a lifelong diet is a crucial part of the therapy since pharmacological therapy is available for only a few conditions and patients. The implementation of a low natural protein diet with a reduced intake of natural protein and the complementary use of synthetic amino acid mixtures is described using the examples of phenylketonuria and urea cycle disorders focusing on children and adolescents. For phenylketonuria, the amino acid supplement is free of phenylalanine whereas for urea cycle disorders, it exclusively consists of essential amino acids. The dietary treatment aims to maintain metabolic stability and to prevent accumulation of toxic metabolites. At the same time, the nutritional requirements to ensure growth and development must be met. Therefore, patients need to follow strict rules regarding the choice of food products. This restrictive therapy interferes with the desire for autonomy and the joy of eating and often results in a reduced quality of life.Following the diet is crucial for a favorable outcome. To meet its requirements, patients and their families are provided with training. It is a~great challenge not only to support the patients and their families in all practical aspects of dietary management, but also to motivate them to lifelong adherence in order to ensure the best possible outcome.Bei vielen angeborenen Stoffwechselkrankheiten ist eine lebensbegleitende Diät von Geburt an fester Bestandteil der Therapie. Alternative medikamentöse Therapieansätze stehen erst für einige wenige Patienten zur Verfügung. Am Beispiel der Phenylketonurie und der Harnstoffzyklusstörungen wird das Prinzip der eiweißdefinierten Diät mit dem Schwerpunkt auf Kinder und Jugendliche erläutert. Die Herausforderungen, die sich bei dieser Ernährungstherapie ergeben, werden aufgezeigt. Bei der eiweißdefinierten Diät erfolgt eine verminderte Zufuhr von natürlichem Protein, ergänzt durch die Gabe spezieller Aminosäuremischungen. Diese enthalten bei der Phenylketonurie kein Phenylalanin, bei den Harnstoffzyklusdefekten ausschließlich essenzielle Aminosäuren. Mithilfe der Diät soll zum einen eine gute metabolische Einstellung erreicht und die Anhäufung toxischer Metabolite vermieden werden. Zum anderen muss eine bedarfsdeckende Energie- und Nährstoffversorgung für das adäquate Wachstum und die Entwicklung des Kindes gewährleistet sein. Für die Patienten bedeutet dies, sich an restriktive Vorgaben bei der Lebensmittelauswahl halten zu müssen. Diese konkurrieren oft mit dem Bedürfnis nach Freiheit/Spontaneität und dem Genuss bei der Nahrungsaufnahme. Viele Patienten empfinden ihre Diät daher als drastische Einschränkung der Lebensqualität. Eine konsequente Umsetzung der Diät ist entscheidend für die Prognose der Erkrankungen. Hierfür bringen die Patienten und ihre Familien oft unterschiedliche Voraussetzung und Fähigkeiten mit. Für Therapeuten stellt es eine große Herausforderung dar, die Patienten nicht nur bei der praktischen Umsetzung ihrer Diät in allen Lebensabschnitten zu unterstützen, sondern auch zu einer langfristigen Adhärenz zu motivieren, um ein bestmögliches Outcome zu erreichen

    The histone chaperones Vps75 and Nap1 form ring-like, tetrameric structures in solution

    Get PDF
    NAP-1 fold histone chaperones play an important role in escorting histones to and from sites of nucleosome assembly and disassembly. The two NAP-1 fold histone chaperones in budding yeast, Vps75 and Nap1, have previously been crystalized in a characteristic homodimeric conformation. In this study, a combination of small angle X-ray scattering, multi angle light scattering and pulsed electron–electron double resonance approaches were used to show that both Vps75 and Nap1 adopt ring-shaped tetrameric conformations in solution. This suggests that the formation of homotetramers is a common feature of NAP-1 fold histone chaperones. The tetramerisation of NAP-1 fold histone chaperones may act to shield acidic surfaces in the absence of histone cargo thus providing a ‘self-chaperoning’ type mechanism

    Family-specific, novel, deleterious germline variants provide a rich resource to identify genetic predispositions for BRCAx familial breast cancer

    Get PDF
    BACKGROUND: Genetic predisposition is the primary risk factor for familial breast cancer. For the majority of familial breast cancer, however, the genetic predispositions remain unknown. All newly identified predispositions occur rarely in disease population, and the unknown genetic predispositions are estimated to reach up to total thousands. Family unit is the basic structure of genetics. Because it is an autosomal dominant disease, individuals with a history of familial breast cancer must carry the same genetic predisposition across generations. Therefore, focusing on the cases in lineages of familial breast cancer, rather than pooled cases in disease population, is expected to provide high probability to identify the genetic predisposition for each family. METHODS: In this study, we tested genetic predispositions by analyzing the family-specific variants in familial breast cancer. Using exome sequencing, we analyzed three families and 22 probands with BRCAx (BRCA-negative) familial breast cancer. RESULTS: We observed the presence of family-specific, novel, deleterious germline variants in each family. Of the germline variants identified, many were shared between the disease-affected family members of the same family but not found in different families, which have their own specific variants. Certain variants are putative deleterious genetic predispositions damaging functionally important genes involved in DNA replication and damaging repair, tumor suppression, signal transduction, and phosphorylation. CONCLUSIONS: Our study demonstrates that the predispositions for many BRCAx familial breast cancer families can lie in each disease family. The application of a family-focused approach has the potential to detect many new predispositions

    The impact of capital structure on the decision to outsource with long term contracts

    Get PDF
    This paper analyzes how capital structure affects the firms’ strategic choice between outsourcing with long term contracts and outsourcing to the spot market. When outsourcing to the spot market firms are exposed to price uncertainty, whereas a long term contract allows them to set in advance the outsourcing price. We show that, to the extent that leverage and uncertainty can lead to financial distress costs in bad states of nature, firms may use long term contracts as a risk management device to hedge input price uncertainty.N/

    Bats Use Magnetite to Detect the Earth's Magnetic Field

    Get PDF
    While the role of magnetic cues for compass orientation has been confirmed in numerous animals, the mechanism of detection is still debated. Two hypotheses have been proposed, one based on a light dependent mechanism, apparently used by birds and another based on a “compass organelle” containing the iron oxide particles magnetite (Fe3O4). Bats have recently been shown to use magnetic cues for compass orientation but the method by which they detect the Earth's magnetic field remains unknown. Here we use the classic “Kalmijn-Blakemore” pulse re-magnetization experiment, whereby the polarity of cellular magnetite is reversed. The results demonstrate that the big brown bat Eptesicus fuscus uses single domain magnetite to detect the Earths magnetic field and the response indicates a polarity based receptor. Polarity detection is a prerequisite for the use of magnetite as a compass and suggests that big brown bats use magnetite to detect the magnetic field as a compass. Our results indicate the possibility that sensory cells in bats contain freely rotating magnetite particles, which appears not to be the case in birds. It is crucial that the ultrastructure of the magnetite containing magnetoreceptors is described for our understanding of magnetoreception in animals

    Multicenter Breast Cancer Collaborative Registry

    Get PDF
    The Breast Cancer Collaborative Registry (BCCR) is a multicenter web-based system that efficiently collects and manages a variety of data on breast cancer (BC) patients and BC survivors. This registry is designed as a multi-tier web application that utilizes Java Servlet/JSP technology and has an Oracle 11g database as a back-end. The BCCR questionnaire has accommodated standards accepted in breast cancer research and healthcare. By harmonizing the controlled vocabulary with the NCI Thesaurus (NCIt) or Systematized Nomenclature of Medicine-Clinical Terms (SNOMED-CT), the BCCR provides a standardized approach to data collection and reporting. The BCCR has been recently certified by the National Cancer Institute’s Center for Biomedical Informatics and Information Technology (NCI CBIIT) as a cancer Biomedical Informatics Grid (caBIG®) Bronze Compatible product
    corecore