108 research outputs found

    Dynamic Properties of Charmonium

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    Nonrelativistic quark models of charmonia are tested by comparison of theoretical charmonium decay constants, form factors, and γγ\gamma\gamma widths with experiment and lattice gauge computations. The importance of relativistic effects, a running coupling, and the correct implementation of bound state effects are demonstrated. We describe how an improved model and computational techniques resolve several outstanding issues in previous nonrelativistic quark models such as the use of `correction' factors in quark model form factors, artificial energy prescriptions in decay constant calculations, and ad hoc phase space modifications. We comment on the small experimental value of fψâ€Čâ€Čf_{\psi''} and the D-wave component of the J/ψJ/\psi. Decay constants and γγ\gamma\gamma widths for bottomonium are also presented.Comment: 22 pages, 22 ps figures (table entries corrected, text modified

    ASKyphoplan: a program for deformity planning in ankylosing spondylitis

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    A closing wedge osteotomy of the lumbar spine may be considered to correct posture and spinal balance in progressive thoracolumbar kyphotic deformity caused by ankylosing spondylitis (AS). Adequate deformity planning is essential for reliable prediction of the effect of surgical correction of the spine on the sagittal balance and horizontal gaze of the patient. The effect of a spinal osteotomy on the horizontal gaze is equal to the osteotomy angle. However, the effect of a spinal osteotomy on the sagittal balance depends on both the correction angle and the level of osteotomy simultaneously. The relation between the correction angle, the level of osteotomy and the sagittal balance of the spine can be expressed by a mathematical equation. However, this mathematical equation is not easily used in daily practice. We present the computer program ASKyphoplan that analyses and visualizes the planning procedure for sagittal plane corrective osteotomies of the spine in AS. The relationship between the planned correction angle, level of osteotomy and sagittal balance are coupled into the program. The steps taken during an ASKyphoplan run are outlined, and the clinical application is discussed. The application of the program is illustrated by the analysis of the data from a patient recently treated by a lumbar osteotomy in AS. The software can be used free of charge on the internet at http://www.stega.nl under the heading “research” in the menu

    The development of hemispheric asymmetry in human motion VEPs

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    AbstractIn six healthy adults we examined the sources underlying P1 and N2 of the motion VEP. For this purpose we acquired, in addition to the VEP, MRI images and patterns of regional cerebral blood flow with SPECT for three of the subjects. With the same motion stimulus we also examined the spatial distribution of N2 in children. In both adults and children left and right half-field responses were compared. It was found that N2 is generated by extrastriate activity and that motion stimuli are not equivalently processed in the two cerebral hemispheres. In adults, N2 dominates in one hemisphere irrespective of the visual half-field used for stimulation whereas children show an ipsilateral maximum for N2 upon half-field presentation

    Complement activation during OKT3 treatment: A possible explanation for respiratory side effects

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    Complement activation during OKT3 treatment: A possible explanation for respiratory side effects. Respiratory side effects that sometimes occur during treatment with anti-CD3 MAb OKT3 might result from pulmonary sequestration of activated neutrophils. Therefore, we studied complement activation in relation to activation and pulmonary sequestration of neutrophils during antirejection treatment with OKT3. In each of nine patients studied, plasma C3a-desarg and C4b/c levels increased compared with pretreatment values already in the first sample taken 15 minutes after the first dose of OKT3 (P < 0.05), with peak values at 15 and 30 minutes, respectively. Levels of neutrophil degranulation product elastase (complexed to α1-antitrypsin) also increased already at 15 minutes after the first dose of OKT3 (P < 0.05), which is before elevated levels of the cytokines TNFα, IL-6 or IL-8 were detectable. In contrast, upon subsequent OKT3 administrations or in the control group treated with methylprednisolone, neither complement activation, cytokine release nor neutrophil degranulation occurred. In five studied patients treated with OKT3, pulmonary sequestration of radiolabeled granulocytes was observed from 3 until 15 minutes after the first dose of OKT3, together with peripheral blood granulocytopenia, which lasted at least 30 minutes. In conclusion, we demonstrate a simultaneous activation of complement and pulmonary sequestration of activated granulocytes immediately following the first dose of OKT3. These phenomena may be involved in the development of respiratory side effects complicating this therapy

    Mesons with Beauty and Charm: Spectroscopy

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    Applying knowledge of the interaction between heavy quarks derived from the study of cc‟c\overline{c} and bb‟b\overline{b} bound states, we calculate the spectrum of cb‟c\overline{b} mesons. We compute transition rates for the electromagnetic and hadronic cascades that lead from excited states to the 1S0^1\text{S}_0 ground state, and briefly consider the prospects for experimental observation of the spectrum.Comment: 32 pages + 2 uuencoded PostScript figures Fermilab-Pub-94/032-

    Cost Analysis From a Randomized Comparison of Immediate Versus Delayed Angiography After Cardiac Arrest

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    Background In patients with out‐of‐hospital cardiac arrest without ST‐segment elevation, immediate coronary angiography did not improve clinical outcomes when compared with delayed angiography in the COACT (Coronary Angiography After Cardiac Arrest) trial. Whether 1 of the 2 strategies has benefits in terms of health care resource use and costs is currently unknown. We assess the health care resource use and costs in patients with out‐of‐hospital cardiac arrest. Methods and Results A total of 538 patients were randomly assigned to a strategy of either immediate or delayed coronary angiography. Detailed health care resource use and cost‐prices were collected from the initial hospital episode. A generalized linear model and a gamma distribution were performed. Generic quality of life was measured with the RAND‐36 and collected at 12‐month follow‐up. Overall total mean costs were similar between both groups (EUR 33 575±19 612 versus EUR 33 880±21 044; P=0.86). Generalized linear model: (ÎČ, 0.991; 95% CI, 0.894–1.099; P=0.86). Mean procedural costs (coronary angiography and percutaneous coronary intervention, coronary artery bypass graft) were higher in the immediate angiography group (EUR 4384±3447 versus EUR 3028±4220; P<0.001). Costs concerning intensive care unit and ward stay did not show any significant difference. The RAND‐36 questionnaire did not differ between both groups. Conclusions The mean total costs between patients with out‐of‐hospital cardiac arrest randomly assigned to an immediate angiography or a delayed invasive strategy were similar during the initial hospital stay. With respect to the higher invasive procedure costs in the immediate group, a strategy awaiting neurological recovery followed by coronary angiography and planned revascularization may be considered. Registration URL: https://trialregister.nl; Unique identifier: NL4857

    Sex differences in patients with out-of-hospital cardiac arrest without ST-segment elevation:A COACT trial substudy

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    Background: Whether sex is associated with outcomes of out-of-hospital cardiac arrest (OHCA) is unclear. Objectives: This study examined sex differences in survival in patients with OHCA without ST-segment elevation myocardial infarction (STEMI). Methods: Using data from the randomized controlled Coronary Angiography after Cardiac Arrest (COACT) trial, the primary point of interest was sex differences in OHCA-related one-year survival. Secondary points of interest included the benefit of immediate coronary angiography compared to delayed angiography until after neurologic recovery, angiographic and clinical outcomes. Results: In total, 522 patients (79.1% men) were included. Overall one-year survival was 59.6% in women and 63.4% in men (HR 1.18; 95% CI: 0.761.81;p = 0.47). No cardiovascular risk factors were found that modified survival. Women less often had significant coronary artery disease (CAD) (37.0% vs. 71.3%; p < 0.001), but when present, they had a worse prognosis than women without CAD (HR 3.06; 95% CI 1.31-7.19; p = 0.01). This was not the case for men (HR 1.05; 95% CI 0.67-1.65; p = 0.83). In both sexes, immediate coronary angiography did not improve one-year survival compared to delayed angiography (women, odds ratio (OR) 0.87; 95% CI 0.58-1.30;p = 0.49; vs. men, OR 0.97; 95% CI 0.45-2.09; p = 0.93). Conclusion: In OHCA patients without STEMI, we found no sex differences in overall one-year survival. Women less often had significant CAD, but when CAD was present they had worse survival than women without CAD. This was not the case for men. Both sexes did not benefit from a strategy of immediate coronary angiography as compared to delayed strategy with respect to one-year survival

    Coronary Angiography After Cardiac Arrest Without ST Segment Elevation:One-Year Outcomes of the COACT Randomized Clinical Trial

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    Importance: Ischemic heart disease is a common cause of cardiac arrest. However, randomized data on long-term clinical outcomes of immediate coronary angiography and percutaneous coronary intervention (PCI) in patients successfully resuscitated from cardiac arrest in the absence of ST segment elevation myocardial infarction (STEMI) are lacking. Objective: To determine whether immediate coronary angiography improves clinical outcomes at 1 year in patients after cardiac arrest without signs of STEMI, compared with a delayed coronary angiography strategy. Design, Setting, and Participants: A prespecified analysis of a multicenter, open-label, randomized clinical trial evaluated 552 patients who were enrolled in 19 Dutch centers between January 8, 2015, and July 17, 2018. The study included patients who experienced out-of-hospital cardiac arrest with a shockable rhythm who were successfully resuscitated without signs of STEMI. Follow-up was performed at 1 year. Data were analyzed, using the intention-to-treat principle, between August 29 and October 10, 2019. Interventions: Immediate coronary angiography and PCI if indicated or coronary angiography and PCI if indicated, delayed until after neurologic recovery. Main Outcomes and Measures: Survival, myocardial infarction, revascularization, implantable cardiac defibrillator shock, quality of life, hospitalization for heart failure, and the composite of death or myocardial infarction or revascularization after 1 year. Results: At 1 year, data on 522 of 552 patients (94.6%) were available for analysis. Of these patients, 413 were men (79.1%); mean (SD) age was 65.4 (12.3) years. A total of 162 of 264 patients (61.4%) in the immediate angiography group and 165 of 258 patients (64.0%) in the delayed angiography group were alive (odds ratio, 0.90; 95% CI, 0.63-1.28). The composite end point of death, myocardial infarction, or repeated revascularization since the index hospitalization was met in 112 patients (42.9%) in the immediate group and 104 patients (40.6%) in the delayed group (odds ratio, 1.10; 95% CI, 0.77-1.56). No significant differences between the groups were observed for the other outcomes at 1-year follow-up. For example, the rate of ICD shocks was 20.4% in the immediate group and 16.2% in the delayed group (odds ratio, 1.32; 95% CI, 0.66-2.64). Conclusions and Relevance: In this trial of patients successfully resuscitated after out-of-hospital cardiac arrest and without signs of STEMI, a strategy of immediate angiography was not found to be superior to a strategy of delayed angiography with respect to clinical outcomes at 1 year. Coronary angiography in this patient group can therefore be delayed until after neurologic recovery without affecting outcomes
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