1,120 research outputs found

    Manipulation of Light with Magneto-optic Stripe Domain Films

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    Magnetic diffraction grating materials, being developed to provide a simple means of deflecting light in a two dimensional, solid state fashion are discussed. The most promising material, for several applications, appears to be bismuth substituted iron garnet films in epitaxial form. Calculations indicate that deflection efficiency greater than 60% is possible in the near infrared region of the spectrum. Within the field of view of the deflector, measurements predict that 105 resolvable spots can be expected. Applications include: (1) general purpose deflection of free laser light, (2) image processing of extended sources such as transparencies, (3) programmable lensing, and (4) fiber optic matrix switching

    Comparison of gene expression in CD34+ cells from bone marrow and G-CSF-mobilized peripheral blood by high-density oligonucleotide array analysis - Supplemental Materials Only.

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    A prospective randomized trial has shown that there is a survival advantage for allogeneic transplant recipients who received granulocyte colony-stimulating factor (G-CSF)-stimulated peripheral blood mononuclear cells (GPBMC) versus those who received bone marrow (BM) as a source of stem cells. The biological basis for this advantage is not clear and may be attributable to qualitative as well as quantitative differences in the CD34 cells, T cells, and/or the monocytes transplanted. To begin to address this issue, gene expression patterns in CD34 cells isolated from these 2 stem cell sources were compared to identify functional pathways that may distinguish these 2 populations. CD34 cells were isolated to purity from the BM and peripheral blood stem cells of multiple healthy donors. (The complete data set will be available at http://parma.fhcrc.org/lgraf upon publication.) Two separate RNA preparations from pooled samples from both sources were analyzed by Affymetrix Oligonucleotide Array chips for expression of over 6400 human genes. Comparative analyses among the samples showed that a small set of 28 sequences increased and 38 sequences decreased in expression more than 3-fold in both of the GPBMC samples compared to those in BM samples. More highly expressed genes include several for nuclear proteins and transcriptional factors. Functional categorization of the genes decreased in expression indicated sequences influential in cell cycle progression, in agreement with the recognized quiescence of circulating CD34 cells. Multiple transcriptional regulators and chemokines were also found to be decreased. These data emphasize that in addition to increased numbers of CD34 cells, G-CSF mobilization also results in significant qualitative changes. Whether they impact engraftment remains to be determined

    Antibandwidth of Complete k-ary Trees

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    AbstractThe antibandwidth problem is to label vertices of a n-vertex graph injectively by 1,2,3,…n, so that the minimum difference between labels of adjacent vertices is maximised. The problem is motivated by the obnoxious facility location problem, radiocolouring, work and game scheduling and is dual to the well known bandwidth problem. We prove exact results for the antibandwidth of complete k-ary trees, k even, and estimate the parameter for odd k up to the second order term. This extends previous results for complete binary trees

    Statin Use Is Prospectively Associated With New-Onset Diabetes After Transplantation in Renal Transplant Recipients

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    OBJECTIVE New-onset diabetes after transplantation (NODAT) is frequent and worsens graft and patient outcomes in renal transplant recipients (RTRs). In the general population, statins are diabetogenic. This study investigated whether statins also increase NODAT risk in RTRs. RESEARCH DESIGN AND METHODS From a prospective longitudinal study of 606 RTRs (functioning allograft >1year,single academic center, follow-up: median 9.6 [range, 6.6–10.2] years), 95 patients using statins were age-and sex-matched to RTRs not on statins (all diabetes-free at inclusion). RESULTS NODAT incidence was 7.2% (73.3% of these on statins). In Kaplan-Meier (log-rank test, P 5 0.017) and Cox regression analyses (HR 3.86 [95% CI 1.21–12.27]; P 5 0.022), statins were prospectively associated with incident NODAT, even independent of several relevant confounders including immunosuppressive medication and biomarkers of glucose homeostasis. CONCLUSIONS This study demonstrates that statin use is prospectively associated with the development of NODAT in RTRs independent of other recognized risk factors

    Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event

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    Coronal mass ejections (CMEs) erupt and expand in a magnetically structured solar corona. Various indirect observational pieces of evidence have shown that the magnetic field of CMEs reconnects with surrounding magnetic fields, forming, e.g., dimming regions distant from the CME source regions. Analyzing Solar Dynamics Observatory (SDO) observations of the eruption from AR 11226 on 2011 June 7, we present the first direct evidence of coronal magnetic reconnection between the fields of two adjacent ARs during a CME. The observations are presented jointly with a data-constrained numerical simulation, demonstrating the formation/intensification of current sheets along a hyperbolic flux tube (HFT) at the interface between the CME and the neighbouring AR 11227. Reconnection resulted in the formation of new magnetic connections between the erupting magnetic structure from AR 11226 and the neighboring active region AR 11227 about 200 Mm from the eruption site. The onset of reconnection first becomes apparent in the SDO/AIA images when filament plasma, originally contained within the erupting flux rope, is re-directed towards remote areas in AR 11227, tracing the change of large-scale magnetic connectivity. The location of the coronal reconnection region becomes bright and directly observable at SDO/AIA wavelengths, owing to the presence of down-flowing cool, dense (10^{10} cm^{-3}) filament plasma in its vicinity. The high-density plasma around the reconnection region is heated to coronal temperatures, presumably by slow-mode shocks and Coulomb collisions. These results provide the first direct observational evidence that CMEs reconnect with surrounding magnetic structures, leading to a large-scale re-configuration of the coronal magnetic field.Comment: 12 pages, 12 figure

    Finite-volume effects and the electromagnetic contributions to kaon and pion masses

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    We report on the MILC Collaboration calculation of electromagnetic effects on light pseudoscalar mesons. The simulations employ asqtad staggered dynamical quarks in QCD plus quenched photons, with lattice spacings varying from 0.12 to 0.06 fm. Finite volume corrections for the MILC realization of lattice electrodynamics have been calculated in chiral perturbation theory and applied to the lattice data. These corrections differ from those calculated by Hayakawa and Uno because our treatment of zero modes differs from theirs. Updated results for the corrections to "Dashen's theorem" are presented.Comment: 7 pages, 2 figures. Presented at Lattice 2014, Columbia University, June 23-28, 201

    Serum antibodies in first-degree relatives of patients with IBD: A marker of disease susceptibility? A follow-up pilot-study after 7 years

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    Introduction: Various disease-specific serum antibodies were described in patients with inflammatory bowel disease and their yet healthy first-degree relatives. In the latter, serum antibodies are commonly regarded as potential markers of disease susceptibility. The present long-term follow-up study evaluated the fate of antibody-positive first-degree relatives. Patients and Methods: 25 patients with Crohn's disease, 19 patients with ulcerative colitis and 102 first-degree relatives in whom presence of ASCA, pANCA, pancreatic- and goblet-cell antibodies had been assessed were enrolled. The number of incident cases with inflammatory bowel disease was compared between antibody-positive and antibody-negative first-degree relatives 7 years after storage of serum samples. Results: 34 of 102 (33%) first-degree relatives were positive for at least one of the studied serum antibodies. In the group of first-degree relatives, one case of Crohn's disease and one case of ulcerative colitis were diagnosed during the follow-up period. However, both relatives did not display any of the investigated serum antibodies (p = 1). Discussion: The findings of our pilot study argue against a role of serum antibodies as a marker of disease susceptibility in first-degree relatives of patients with inflammatory bowel disease. However, these data have to await confirmation in larger ideally prospective multicenter studies before definite conclusions can be drawn

    “A sustained, productive, constructive relationship with someone who can help”—A qualitative exploration of the experiences of help seekers and support persons using the emergency department during a suicide crisis

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    For Australians experiencing a suicide crisis, the emergency department (ED) is the recommended point of contact for intervention and to ensure personal safety. However, negative ED experiences can deter individuals from returning, thus impacting future suicide risk. In order to improve the ED environment for individuals in suicidal crisis, an in-depth understanding of this experience is needed. In-depth semi-structured interviews with 17 help seekers and 16 support persons were conducted. A grounded theory approach uncovered a core organising concept—all participants wanted a “a sustained, productive, constructive relationship with someone who can help” during the ED visit—which guided analysis. Thematic analysis resulted in two themes and four subthemes exploring the systemic and interpersonal aspects of the ED visit and the roadblocks and pathways to development of the relationship. Interpersonal factors included aspects of staff interaction and presence of a support person. Systemic factors related to aspects controlled by the physical space and internal policies and procedures and included aspects such as the chaotic environment, long waiting times, and access to staff. Overwhelmingly, there were more roadblocks than pathways reported by participants. Improving the ED environment, increasing staff training and encouraging the presence of support persons may help mitigate some of these roadblocks
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