134 research outputs found
Far-infrared vibrational properties of high-pressure-high-temperature C60 polymers and the C60 dimer
We report high-resolution far-infrared transmission measurements of the 2 + 2 cycloaddition C-60 dimer and two-dimensional rhombohedral and one-dimensional orthorhombic high-pressure high-temperature C60 polymers. In the spectral region investigated(20-650 cm(-1)), we see no low-energy interball modes, but symmetry breaking of the linked C-60 balls is evident in the complex spectrum of intramolecular modes. Experimental features suggest large splittings or frequency shifts of some IhC60-derived modes that are activated by symmetry reduction, implying that the balls are strongly distorted in these structures. We have calculated the vibrations of all three systems by first-principles quantum molecular dynamics and use them to assign the predominant IhC60 symmetries of observed modes. Pur calculations show unprecedentedly large downshifts of T-1u(2)-derived modes and extremely large splittings of other modes, both of which are consistent with the experimental spectra. For the rhombohedral and orthorhombic polymers, the T-1u(2)-derived mode that is polarized along the bonding direction is calculated to downshift below any T-1u(1)-derived modes. We also identify a previously unassigned feature near 610 cm(-1) in all three systems as a widely split or shifted mode derived from various silent IhC60 vibrations, confirming a strong perturbation model for these linked fullerene structures
Epidemiologic Study of Dental Caries Experience and Between-Meal Eating Patterns
The relationship between dental caries and between-meal snacks was investigated in a study of 1,486 high school students. The participants completed a questionnaire on between-meal habits and then were given dental examinations. The lack of differences in dental caries between racial and geographic groups was not related to the frequency of sucrose-containing, between-meal snacks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66591/2/10.1177_00220345730520022501.pd
Tests of CPT Invariance at Neutrino Factories
We investigate possible tests of CPT invariance on the level of event rates
at neutrino factories. We do not assume any specific model but phenomenological
differences in the neutrino-antineutrino masses and mixing angles in a Lorentz
invariance preserving context, such as it could be induced by physics beyond
the Standard Model. We especially focus on the muon neutrino and antineutrino
disappearance channels in order to obtain constraints on the
neutrino-antineutrino mass and mixing angle differences; we found, for example,
that the sensitivity
could be achieved.Comment: 6 pages, 1 figure, RevTeX4. Final version to be published in Phys.
Rev.
Dynamical properties of liquid Al near melting. An orbital-free molecular dynamics study
The static and dynamic structure of liquid Al is studied using the orbital
free ab-initio molecular dynamics method. Two thermodynamic states along the
coexistence line are considered, namely T = 943 K and 1323 K for which X-ray
and neutron scattering data are available. A new kinetic energy functional,
which fulfills a number of physically relevant conditions is employed, along
with a local first principles pseudopotential. In addition to a comparison with
experiment, we also compare our ab-initio results with those obtained from
conventional molecular dynamics simulations using effective interionic pair
potentials derived from second order pseudopotential perturbation theory.Comment: 15 pages, 12 figures, 2 tables, submitted to PR
Opportunistic screening models for high-risk men and women to detect diastolic dysfunction and heart failure with preserved ejection fraction in the community
Background: The prevalence of undetected left ventricular diastolic dysfunction is high, especially in the elderly with
comorbidities. Left ventricular diastolic dysfunction is a prognostic indicator of heart failure, in particularly of heart
failure with preserved ejection fraction and of future cardiovascular and all-cause mortality. Therefore we aimed to
develop sex-specific diagnostic models to enable the early identification of men and women at high-risk of left ventricular
diastolic dysfunction with or without symptoms of heart failure who require more aggressive preventative strategies.
Design: Individual patient data from four primary care heart failure-screening studies were analysed (1371 participants,
excluding patients classified as heart failure and left ventricular ejection fraction <50%).
Methods: Eleven candidate predictors were entered into logistic regression models to be associated with the presence
of left ventricular diastolic dysfunction/heart failure with preserved ejection fraction in men and women separately.
Internal-external cross-validation was performed to develop and validate the models.
Results: Increased age and b-blocker therapy remained as predictors in both the models for men and women. The model
for men additionally consisted of increased body mass index, moderate to severe shortness of breath, increased pulse
pressure and history of ischaemic heart disease. The models performed moderately and similarly well in men (c-statistics
range 0.60–0.75) and women (c-statistics range 0.51–0.76) and the performance improved significantly following the addition of N-terminal pro b-type natriuretic peptide (c-statistics range 0.61–0.80 in women and 0.68–0.80 in men).
Conclusions: We provide an easy-to-use screening tool for use in the community, which can improve the early
detection of left ventricular diastolic dysfunction/heart failure with preserved ejection fraction in high-risk men and
women and optimise tailoring of preventive interventions
Effects of the high-density lipoprotein mimetic agent CER-001 on coronary atherosclerosis in patients with acute coronary syndromes: a randomized trial†
Aim High-density lipoproteins (HDLs) have several potentially protective vascular effects. Most clinical studies of therapies targeting HDL have failed to show benefits vs. placebo. Objective To investigate the effects of an HDL-mimetic agent on atherosclerosis by intravascular ultrasonography (IVUS) and quantitative coronary angiography (QCA). Design and setting A prospective, double-blinded, randomized trial was conducted at 51 centres in the USA, the Netherlands, Canada, and France. Intravascular ultrasonography and QCA were performed to assess coronary atherosclerosis at baseline and 3 (2-5) weeks after the last study infusion. Patients Five hundred and seven patients were randomized; 417 and 461 had paired IVUS and QCA measurements, respectively. Intervention Patients were randomized to receive 6 weekly infusions of placebo, 3 mg/kg, 6 mg/kg, or 12 mg/kg CER-001. Main outcome measures The primary efficacy parameter was the nominal change in the total atheroma volume. Nominal changes in per cent atheroma volume on IVUS and coronary scores on QCA were also pre-specified endpoints. Results The nominal change in the total atheroma volume (adjusted means) was −2.71, −3.13, −1.50, and −3.05 mm3 with placebo, CER-001 3 mg/kg, 6 mg/kg, and 12 mg/kg, respectively (primary analysis of 12 mg/kg vs. placebo: P = 0.81). There was also no difference among groups for the nominal change in per cent atheroma volume (0.02, −0.02, 0.01, and 0.19%; nominal P = 0.53 for 12 mg/kg vs. placebo). Change in the coronary artery score was −0.022, −0.036, −0.022, and −0.015 mm (nominal P = 0.25, 0.99, 0.55), and change in the cumulative coronary stenosis score was −0.51, 2.65, 0.71, and −0.77% (compared with placebo, nominal P = 0.85 for 12 mg/kg and nominal P = 0.01 for 3 mg/kg). The number of patients with major cardiovascular events was 10 (8.3%), 16 (13.3%), 17 (13.7%), and 12 (9.8%) in the four groups. Conclusion CER-001 infusions did not reduce coronary atherosclerosis on IVUS and QCA when compared with placebo. Whether CER-001 administered in other regimens or to other populations could favourably affect atherosclerosis must await further study. Name of the trial registry: Clinicaltrials.gov; Registry's URL: http://clinicaltrials.gov/ct2/show/NCT01201837?term=cer-001&rank=2; Trial registration number: NCT0120183
Association of CSSM066 and ILSTS011 microsatellite markers and thyroglobulin gene SNP with backfat in Canchim cattle
Canchim, a synthetic breed of cattle derived from the Charolais and Zebu group has been used in the beef-cattle industry in Brazil as an alternative for intensifying production. One of the main concerns with this breed is its poor fat deposition and consequently, there is an effort to increase the performance for this trait. The thyroglobulin gene is located in a QTL region for fat deposition, and reports describe the influence of a polymorphism in the 5´ leader sequence of that gene on marbling and subcutaneous fat thickness. This study analyzed the association of this polymorphism in the thyroglobulin gene, as well as of two flanking microsatellite markers, CSSM066 and ILSTS011, with backfat thickness in 987 Canchim beef cattle. The CSSM066 and ILSTS011 microsatellite markers have a effect on fat thickness in the studied populations. However, this trait did not have association with the polymorphism of the thyroglobulin gene, which suggests that other genes of bovine chromosome 14 may be responsible for the variation in this trait
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