785 research outputs found
Plant Stanol Esters Lower Serum Triacylglycerol Concentrations via a Reduced Hepatic VLDL-1 Production
Plant stanol esters not only lower low density lipoprotein cholesterol but also have previously been shown to lower serum triacylglycerol (TAG) concentrations, especially in subjects with elevated TAG concentrations. To find a possible explanation, we explored changes in serum lipoprotein profiles, as measured with nuclear magnetic resonance. For this, serum samples from two parallel-designed controlled studies were evaluated before and 8Â weeks after the consumption of plant stanol esters. In the first study, dyslipidemic metabolic syndrome subjects participated and in the second study normolipidemic subjects. In metabolic syndrome subjects, plant stanol esters lowered concentrations of large (>60Â nm) and medium (35â60Â nm) VLDL particles as compared to controls. In normolipidemic subjects, the serum concentration of large VLDL-1 particles was also lowered, although less pronounced. Based on these findings, we hypothesize that the effect of plant stanol esters on serum TAG concentrations origins from a lowered hepatic production of large TAG-rich VLDL-1 particles
Universal logarithmic corrections to entanglement entropies in two dimensions with spontaneously broken continuous symmetries
We explore the R\'enyi entanglement entropies of a one-dimensional (line)
subsystem of length embedded in two-dimensional square lattice
for quantum spin models whose ground-state breaks a continuous symmetry in the
thermodynamic limit. Using quantum Monte Carlo simulations, we first study the
Heisenberg model with antiferromagnetic nearest-neighbor
and ferromagnetic second-neighbor couplings . The signature of SU(2)
symmetry breaking on finite size systems, ranging from up to
clearly appears as a universal additive logarithmic correction to the R\'enyi
entanglement entropies: with , independent of the
R\'enyi index and values of . We confirm this result using a high
precision spin-wave analysis (with restored spin rotational symmetry) on finite
lattices up to sites, allowing to explore further
non-universal finite size corrections and study in addition the case of U(1)
symmetry breaking. Our results fully agree with the prediction
where is the number of Goldstone modes, by Metlitski and Grover
[arXiv:1112.5166].Comment: 6 pages, 6 figure
Improving entanglement and thermodynamic R\'enyi entropy measurements in quantum Monte Carlo
We present a method for improving measurements of the entanglement R\'enyi
entropies in quantum Monte Carlo simulations by relating them with measurements
of participation R\'enyi entropies. Exploiting the capability of building
improved estimators for the latter allows to obtain very good estimates for
entanglement R\'enyi entropies. When considering a full system instead of a
bipartition, the method can be further ameliorated providing access to the
thermodynamic R\'enyi entropies with high accuracy. We also explore a
recently-proposed method for the reconstruction of the entanglement spectrum
from entanglement R\'enyi entropies and finally show how potential entanglement
Hamiltonians may be tested for their validity using a comparison with thermal
R\'enyi entropies.Comment: 15 pages, 11 figure
BEAGLE-AGN I: Simultaneous constraints on the properties of gas in star-forming and AGN narrow-line regions in galaxies
We present the addition of nebular emission from the narrow-line regions
(NLR) surrounding active galactic nuclei (AGN) to BEAGLE (BayEsian Analysis of
GaLaxy sEds). Using a set of idealised spectra, we fit to a set of observables
(emission-line ratios and fluxes) and test the retrieval of different physical
parameters. We find that fitting to standard diagnostic-line ratios from
Baldwin et al. (1981) plus [O II]3726,3729/[O III]5007, Hbeta/ Halpha, [O
I]6300/[O II]3726,3729 and Halpha flux, degeneracies remain between
dust-to-metal mass ratio and ionisation parameter in the NLR gas, and between
slope of the ionizing radiation (characterising the emission from the accretion
disc around the central black hole) and total accretion-disc luminosity. Since
these degeneracies bias the retrieval of other parameters even at maximal
signal-to-noise ratio (S/N), without additional observables, we suggest fixing
the slope of the ionizing radiation and dust-to-metal mass ratios in both NLR
and HII regions. We explore the S/N in Hbeta required for un-biased estimates
of physical parameters, finding that S/N(Hbeta)~10 is sufficient to identify a
NLR contribution, but that higher S/N is required for un-biased parameter
retrieval (~20 for NLR-dominated systems, ~sim30 for objects with
approximately-equal Hbeta contributions from NLR and HII regions). We also
compare the predictions of our models for different line ratios to
previously-published models and data. By adding [He II]4686-line measurements
to a set of published line fluxes for a sample of 463 AGN NLR, we show that our
models with ionisation parameter in the NLR gas can account for the
full range of observed AGN properties in the local Universe.Comment: 22 pages, 18 figures. Submitted to MNRA
Plasma oxyphytosterols most likely originate from hepatic oxidation and subsequent spill-over in the circulation
We evaluated oxyphytosterol (OPS) concentrations in plasma and various tissues of two genetically modified mouse models with either increased cholesterol (apoE KO mice) or increased cholesterol and plant sterol (PS) concentrations (apoExABCG8 dKO mice). Sixteen female apoE KO and 16 dKO mice followed the same standard, low OPS-chow diet. Animals were euthanized at 36 weeks to measure PS and OPS concentrations in plasma, brain, liver and aortic tissue. Cholesterol and oxysteml (OS) concentrations were analyzed as reference for sterol oxidation in general. Plasma campesterol (24.1 +/- 4.3 vs. 11.8 +/- 3.0 mg/dL) and sitosterol (67.4 +/- 12.7 vs. 4.9 +/- 1.1 mg/dL) concentrations were severely elevated in the dKO compared to the apoE KO mice (p < 0.001). Also, in aortic and brain tissue, PS levels were significantly elevated in dKO. However, plasma, aortic and brain OPS concentrations were comparable or even lower in the dKO mice. In contrast, in liver tissue, both PS and OPS concentrations were severely elevated in the dKO compared to apoE KO mice (sum OPS: 7.4 +/- 1.6 vs. 4.1 +/- 0.8 ng/mg, p < 0.001). OS concentrations followed cholesterol concentrations in plasma and all tissues suggesting ubiquitous oxidation. Despite severely elevated PS concentrations, OPS concentrations were only elevated in liver tissue, suggesting that OPS are primarily formed in the liver and plasma concentrations originate from hepatic spill-over into the circulation
The effect of long-term Aronia melanocarpa extract supplementation on cognitive performance, mood, and vascular function: A randomized controlled trial in healthy, middle-aged individuals
Cognitive decline is associated with lifestyle-related factors such as overweight, blood pressure, and dietary composition. Studies have reported beneficial effects of dietary anthocyanins on cognition in older adults and children. However, the effect of anthocyanin-rich Aronia melanocarpa extract (AME) on cognition is unknown. Therefore, this study aimed to determine the effect of long-term supplementation with AME on cognitive performance, mood, and vascular function in healthy, middle-aged, overweight adults. In a randomized double-blind placebo-controlled parallel study, 101 participants either consumed 90 mg AME, 150 mg AME, or placebo for 24 weeks. The grooved pegboard test, number cross-out test, and Stroop test were performed as measures for psychomotor speed, attention, and cognitive flexibility. Mood was evaluated with a visual analogue scale, serum brain-derived neurotrophic factor (BDNF) was determined, and vascular function was assessed by carotid ultrasounds and blood pressure measurements. AME improved psychomotor speed compared to placebo (90 mg AME: change = -3.37; p = 0.009). Furthermore, 150 mg AME decreased brachial diastolic blood pressure compared to 90 mg AME (change = 2.44; p = 0.011), but not compared to placebo. Attention, cognitive flexibility, BDNF, and other vascular parameters were not affected. In conclusion, AME supplementation showed an indication of beneficial effects on cognitive performance and blood pressure in individuals at risk of cognitive decline
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