92 research outputs found

    SN 2005hj: Evidence for Two Classes of Normal-Bright SNe Ia and Implications for Cosmology

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    HET Optical spectra covering the evolution from about 6 days before to about 5 weeks after maximum light and the ROTSE-IIIb unfiltered light curve of the "Branch-normal" Type Ia Supernova SN 2005hj are presented. The host galaxy shows HII region lines at redshift of z=0.0574, which puts the peak unfiltered absolute magnitude at a somewhat over-luminous -19.6. The spectra show weak and narrow SiII lines, and for a period of at least 10 days beginning around maximum light these profiles do not change in width or depth and they indicate a constant expansion velocity of ~10,600 km/s. We analyzed the observations based on detailed radiation dynamical models in the literature. Whereas delayed detonation and deflagration models have been used to explain the majority of SNe Ia, they do not predict a long velocity plateau in the SiII minimum with an unvarying line profile. Pulsating delayed detonations and merger scenarios form shell-like density structures with properties mostly related to the mass of the shell, M_shell, and we discuss how these models may explain the observed SiII line evolution; however, these models are based on spherical calculations and other possibilities may exist. SN 2005hj is consistent with respect to the onset, duration, and velocity of the plateau, the peak luminosity and, within the uncertainties, with the intrinsic colors for models with M_shell=0.2 M_sun. Our analysis suggests a distinct class of events hidden within the Branch-normal SNe Ia. If the predicted relations between observables are confirmed, they may provide a way to separate these two groups. We discuss the implications of two distinct progenitor classes on cosmological studies employing SNe Ia, including possible differences in the peak luminosity to light curve width relation.Comment: ApJ accepted, 31 page

    Determination of monolayer-protected gold nanoparticle ligand–shell morphology using NMR

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    It is accepted that the ligand shell morphology of nanoparticles coated with a monolayer of molecules can be partly responsible for important properties such as cell membrane penetration and wetting. When binary mixtures of molecules coat a nanoparticle, they can arrange randomly or separate into domains, for example, forming Janus, patchy or striped particles. To date, there is no straightforward method for the determination of such structures. Here we show that a combination of one-dimensional and two-dimensional NMR can be used to determine the ligand shell structure of a series of particles covered with aliphatic and aromatic ligands of varying composition. This approach is a powerful way to determine the ligand shell structure of patchy particles; it has the limitation of needing a whole series of compositions and ligands' combinations with NMR peaks well separated and whose shifts due to the surrounding environment can be large enough

    Using DTI to assess white matter microstructure in cerebral small vessel disease (SVD) in multicentre studies

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    Diffusion tensor imaging (DTI) metrics such as fractional anisotropy (FA) and mean diffusivity (MD) have been proposed as clinical trial markers of cerebral small vessel disease (SVD) due to their associations with outcomes such as cognition. However, studies investigating this have been predominantly single-centre. As clinical trials are likely to be multisite, further studies are required to determine whether associations with cognition of similar strengths can be detected in a multicentre setting. One hundred and nine patients (mean age =68 years) with symptomatic lacunar infarction and confluent white matter hyperintensities (WMH) on MRI was recruited across six sites as part of the PRESERVE DTI substudy. After handling missing data, 3T-MRI scanning was available from five sites on five scanner models (Siemens and Philips), alongside neuropsychological and quality of life (QoL) assessments. FA median and MD peak height were extracted from DTI histogram analysis. Multiple linear regressions were performed, including normalized brain volume, WMH lesion load, and n° lacunes as covariates, to investigate the association of FA and MD with cognition and QoL. DTI metrics from all white matter were significantly associated with global cognition (standardized β =0.268), mental flexibility (β =0.306), verbal fluency (β =0.376), and Montreal Cognitive Assessment (MoCA) (β =0.273). The magnitudes of these associations were comparable with those previously reported from single-centre studies found in a systematic literature review. In this multicentre study, we confirmed associations between DTI parameters and cognition, which were similar in strength to those found in previous single-centre studies. The present study supports the use of DTI metrics as biomarkers of disease progression in multicentre studies.This work was supported by the British Heart Foundation and the Stroke Association [grant number TSA BHF 2010/01]; the NIHR-funded Newcastle Biomedical Research Centre; the NIHR Senior Investigator Awards (for H.S.M., J.T.O. and G.A.F.); and the Cambridge University Hospitals NIHR Comprehensive Biomedical Research Centre (for H.S.M. and J.T.O.)

    PRESERVE: Randomized Trial of Intensive Versus Standard Blood Pressure Control in Small Vessel Disease.

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    Background and Purpose: In cerebral small vessel disease, cerebral blood flow and autoregulation are impaired and therefore excessive blood pressure reduction could possibly accelerate white matter damage and worsen outcome. The trial determined, in severe symptomatic cerebral small vessel disease, whether intensive blood pressure lowering resulted in progression of white matter damage assessed using diffusion tensor imaging. Methods: Randomized, parallel, multicenter controlled, blinded-outcomes clinical trial. One hundred eleven participants with magnetic resonance imaging confirmed symptomatic lacunar infarct and confluent white matter hyperintensities and were recruited and randomized to standard (systolic=130–140 mmHg) (N=56) or intensive (systolic<125 mmHg) (N=55) blood pressure targets. The primary end point was change in diffusion tensor imaging white matter mean diffusivity peak height between baseline and 24 months. Secondary end points were other magnetic resonance imaging markers and cognition. Results: Patients were mean 68 years and 60% male. Mean (SD) blood pressure reduced by −15.3 (15.4) and −23.1 (22.04) mm Hg in the standard/intensive groups, respectively (P<0.001). There was no difference between treatment groups for the primary end point: standard, adjusted mean (SE)=12.5×10−3 (0.2×10−3); intensive, 12.5×10−3 (0.2×10−3), P=0.92. In the whole population over 24 months follow-up, there was a significant deterioration in white matter microstructure but no detectable decrease in cognition. Conclusions: Intensive blood pressure lowering in severe cerebral small vessel disease was not associated with progression of white matter damage on diffusion tensor imaging or magnetic resonance imaging. In a multicentre study setting over 2 years, multimodal diffusion tensor imaging-magnetic resonance imaging was more sensitive to detecting change than cognitive testing

    Systematic development and adjustment of the German version of the Supportive and Palliative Care Indicators Tool (SPICT-DE)

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    Abstract Background The Supportive and Palliative Care Indicators tool (SPICT) supports the identification of patients with potential palliative care (PC) needs. An Austrian-German expert group translated SPICT into German (SPICT-DE) in 2014. The aim of this study was the systematic development, refinement, and testing of SPICT-DE for its application in primary care (general practice). Methods SPICT-DE was developed by a multiprofessional research team according to the TRAPD model: translation, review, adjudication, pretesting and documentation. In a pretest, five general practitioners (GPs) rated four case vignettes of patients with different PC needs. GPs were asked to assess whether each patient might benefit from PC or not (I) based on their subjective appraisal (“usual practice”) and (II) by using SPICT-DE. After further refinement, two focus groups with 28 GPs (68% with a further qualification in PC) were conducted to test SPICT-DE. Again, participants rated two selected case vignettes (I) based on their subjective appraisal and (II) by using SPICT-DE. Afterwards, participants reflected the suitability of SPICT-DE for use in their daily practice routine within the German primary care system. Quantitative data were analysed with descriptive statistics and non-parametric tests for small samples. Qualitative data were analysed by conventional content analysis. Focus group discussion was analysed combining formal and conventional content analysis. Results Compared to the spontaneous rating of the case vignettes based on subjective appraisal, participants in both the pretest and the focus groups considered PC more often as being beneficial for the patients described in the case vignettes when using SPICT-DE. Participants in the focus groups agreed that SPICT-DE includes all relevant indicators necessary for an adequate clinical identification of patients who might benefit from PC. Conclusions SPICT-DE supports the identification of patients who might benefit from PC and seems suitable for routine application in general practice in Germany. The systematic development, refinement, and testing of SPICT-DE in this study was successfully completed by using a multiprofessional and participatory approach

    Antiviral activity of the mineralocorticoid receptor NR3C2 against Herpes simplex virus Type 1 (HSV-1) infection

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    Abstract Analysis of a genome-scale RNA interference screen of host factors affecting herpes simplex virus type 1 (HSV-1) revealed that the mineralocorticoid receptor (MR) inhibits HSV-1 replication. As a ligand-activated transcription factor the MR regulates sodium transport and blood pressure in the kidney in response to aldosterone, but roles have recently been elucidated for the MR in other cellular processes. Here, we show that the MR and other members of the mineralocorticoid signalling pathway including HSP90 and FKBP4, possess anti-viral activity against HSV-1 independent of their effect on sodium transport, as shown by sodium channel inhibitors. Expression of the MR is upregulated upon infection in an interferon (IFN) and viral transcriptional activator VP16-dependent fashion. Furthermore, the MR and VP16, together with the cellular co-activator Oct-1, transactivate the hormone response element (HRE) present in the MR promoter and those of its transcriptional targets. As the MR induces IFN expression, our data suggests the MR is involved in a positive feedback loop that controls HSV-1 infection

    Facts, values, and Attention-Deficit Hyperactivity Disorder (ADHD): an update on the controversies

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    The Hastings Center, a bioethics research institute, is holding a series of 5 workshops to examine the controversies surrounding the use of medication to treat emotional and behavioral disturbances in children. These workshops bring together clinicians, researchers, scholars, and advocates with diverse perspectives and from diverse fields. Our first commentary in CAPMH, which grew out of our first workshop, explained our method and explored the controversies in general. This commentary, which grows out of our second workshop, explains why informed people can disagree about ADHD diagnosis and treatment. Based on what workshop participants said and our understanding of the literature, we make 8 points. (1) The ADHD label is based on the interpretation of a heterogeneous set of symptoms that cause impairment. (2) Because symptoms and impairments are dimensional, there is an inevitable "zone of ambiguity," which reasonable people will interpret differently. (3) Many other variables, from different systems and tools of diagnosis to different parenting styles and expectations, also help explain why behaviors associated with ADHD can be interpreted differently. (4) Because people hold competing views about the proper goals of psychiatry and parenting, some people will be more, and others less, concerned about treating children in the zone of ambiguity. (5) To recognize that nature has written no bright line between impaired and unimpaired children, and that it is the responsibility of humans to choose who should receive a diagnosis, does not diminish the significance of ADHD. (6) Once ADHD is diagnosed, the facts surrounding the most effective treatment are complicated and incomplete; contrary to some popular wisdom, behavioral treatments, alone or in combination with low doses of medication, can be effective in the long-term reduction of core ADHD symptoms and at improving many aspects of overall functioning. (7) Especially when a child occupies the zone of ambiguity, different people will emphasize different values embedded in the pharmacological and behavioral approaches. (8) Truly informed decision-making requires that parents (and to the extent they are able, children) have some sense of the complicated and incomplete facts regarding the diagnosis and treatment of ADHD

    Fluid Intelligence and Psychosocial Outcome: From Logical Problem Solving to Social Adaptation

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    While fluid intelligence has proved to be central to executive functioning, logical reasoning and other frontal functions, the role of this ability in psychosocial adaptation has not been well characterized.Lower fluid intelligence scores were associated with physical violence, both in the role of victim and victimizer. Drug intake, especially cannabis, cocaine and inhalants and lower self-esteem were also associated with lower fluid intelligence. Finally, scores on the perceived mental health assessment were better when fluid intelligence scores were higher.Our results show evidence of a strong association between psychosocial adaptation and fluid intelligence, suggesting that the latter is not only central to executive functioning but also forms part of a more general capacity for adaptation to social contexts
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