4,105 research outputs found
Anthocyanins and their physiologically relevant metabolites alter the expression of IL-6 and VCAM-1 in CD40L and oxidized LDL challenged vascular endothelial cells
Scope
In vitro and in vivo studies suggest that dietary anthocyanins modulate cardiovascular disease risk; however, given anthocyanins extensive metabolism, it is likely that their degradation products and conjugated metabolites are responsible for this reported bioactivity.
Methods and results
Human vascular endothelial cells were stimulated with either oxidized LDL (oxLDL) or cluster of differentiation 40 ligand (CD40L) and cotreated with cyanidin-3-glucoside and 11 of its recently identified metabolites, at 0.1, 1, and 10 μM concentrations. Protein and gene expression of IL-6 and VCAM-1 was quantified by ELISA and RT-qPCR. In oxLDL-stimulated cells the parent anthocyanin had no effect on IL-6 production, whereas numerous anthocyanin metabolites significantly reduced IL-6 protein levels; phase II conjugates of protocatechuic acid produced the greatest effects (>75% reduction, p ≤ 0.05). In CD40L-stimulated cells the anthocyanin and its phase II metabolites reduced IL-6 protein production, where protocatechuic acid-4-sulfate induced the greatest reduction (>96% reduction, p ≤ 0.03). Similarly, the anthocyanin and its metabolites reduced VCAM-1 protein production, with ferulic acid producing the greatest effect (>65% reduction, p ≤ 0.04).
Conclusion
These novel data provide evidence to suggest that anthocyanin metabolites are bioactive at physiologically relevant concentrations and have the potential to modulate cardiovascular disease progression by altering the expression of inflammatory mediators
Signatures of anthocyanin metabolites identified in humans inhibit biomarkers of vascular inflammation in human endothelial cells
Scope
The physiological relevance of contemporary cell culture studies is often perplexing, given the use of unmetabolized phytochemicals at supraphysiological concentrations. We investigated the activity of physiologically relevant anthocyanin metabolite signatures, derived from a previous pharmacokinetics study of 500 mg 13C5-cyanidin-3-glucoside in 8 healthy participants, on soluble vascular adhesion molecule-1 (VCAM-1) and interleukin-6 (IL-6) in human endothelial cells.
Methods and results
Signatures of peak metabolites (previously identified at 1, 6 and 24 h post-bolus) were reproduced using pure standards and effects were investigated across concentrations ten-fold lower and higher than observed mean (<5 μM) serum levels. Tumor necrosis factor-α (TNF-α)-stimulated VCAM-1 was reduced in response to all treatments, with maximal effects observed for the 6 h and 24 h profiles. Profiles tested at ten-fold below mean serum concentrations (0.19-0.44 μM) remained active. IL-6 was reduced in response to 1, 6 and 24 h profiles, with maximal effects observed for 6 h and 24 h profiles at concentrations above 2 μM. Protein responses were reflected by reductions in VCAM-1 and IL-6 mRNA, however there was no effect on phosphorylated NFκB-p65 expression.
Conclusion
Signatures of anthocyanin metabolites following dietary consumption reduce VCAM-1 and IL-6 production, providing evidence of physiologically relevant biological activity
Nuclear obscuration and scattering in Seyfert 2 galaxies
We study the relation between gaseous absorbing column density (N),
infrared colors and detectability of the broad lines in a large sample of
Seyfert 2 galaxies(Sy2s). We confirm that Sy2s without polarized broad lines
tend to have cooler 60m/25m colors; this correlation was previously
ascribed to the effect of obscuration towards the nuclear region.
We find some evidence that Sy2s without polarized broad lines have larger
absorbing column density (N) and that a fraction of them are
characterized by dust lanes crossing their nuclei.
However, we find that the IR colors do not correlate with N, in
disagreement with the obscuration scenario.
Also, Sy2s without polarized broad lines follow the same radio-FIR relation
as normal and starburst galaxies, at variance with Sy2s with polarized broad
lines. These results indicate that the lack of broad lines in the polarized
spectrum of Sy2s is mostly due to the contribution/dilution from the host
galaxy or from a circumnuclear starburst, though at a lower extent the
obscuration toward the nuclear region also plays a role.Comment: 6 pages, 4 figures, to appear in A&A
Fabry-Perot interference and spin filtering in carbon nanotubes
We study the two-terminal transport properties of a metallic single-walled
carbon nanotube with good contacts to electrodes, which have recently been
shown [W. Liang et al, Nature 441, 665-669 (2001)] to conduct ballistically
with weak backscattering occurring mainly at the two contacts. The measured
conductance, as a function of bias and gate voltages, shows an oscillating
pattern of quantum interference. We show how such patterns can be understood
and calculated, taking into account Luttinger liquid effects resulting from
strong Coulomb interactions in the nanotube. We treat back-scattering in the
contacts perturbatively and use the Keldysh formalism to treat non-equilibrium
effects due to the non-zero bias voltage. Going beyond current experiments, we
include the effects of possible ferromagnetic polarization of the leads to
describe spin transport in carbon nanotubes. We thereby describe both
incoherent spin injection and coherent resonant spin transport between the two
leads. Spin currents can be produced in both ways, but only the latter allow
this spin current to be controlled using an external gate. In all cases, the
spin currents, charge currents, and magnetization of the nanotube exhibit
components varying quasiperiodically with bias voltage, approximately as a
superposition of periodic interference oscillations of spin- and
charge-carrying ``quasiparticles'' in the nanotube, each with its own period.
The amplitude of the higher-period signal is largest in single-mode quantum
wires, and is somewhat suppressed in metallic nanotubes due to their sub-band
degeneracy.Comment: 12 pages, 6 figure
catena-Poly[[(1,10-phenanthroline-κ2 N,N′)praseodymium(III)]-di-μ-phenoxyacetato-κ4 O:O′-[(1,10-phenanthroline-κ2 N,N′)praseodymium(III)]-di-μ-phenoxyacetato-κ4 O:O′-di-μ-phenoxyacetato-κ3 O,O′:O;κ3 O:O,O′]
The title complex, [Pr2(C8H7O3)6(C12H8N2)2]n, which has an inversion centre midway between the two PrIII atoms of the structural unit, forms a one-dimensional polymer bridged alternately by either two bidentate, or two bidentate and two terdentate, phenoxyacetate carboxylate groups. Each PrIII atom is thus nine-coordinated by two N atoms of a 1,10-phenanthroline ligand and seven O atoms from six phenoxyacetate ligands. The coordination geometry at the PrIII atom is distorted tricapped trigonal prismatic. One phenyl ring is disordered over two positions; the site occupancy factors are ca 0.6 and 0.4
Decentralized Estimation over Orthogonal Multiple-access Fading Channels in Wireless Sensor Networks - Optimal and Suboptimal Estimators
Optimal and suboptimal decentralized estimators in wireless sensor networks
(WSNs) over orthogonal multiple-access fading channels are studied in this
paper. Considering multiple-bit quantization before digital transmission, we
develop maximum likelihood estimators (MLEs) with both known and unknown
channel state information (CSI). When training symbols are available, we derive
a MLE that is a special case of the MLE with unknown CSI. It implicitly uses
the training symbols to estimate the channel coefficients and exploits the
estimated CSI in an optimal way. To reduce the computational complexity, we
propose suboptimal estimators. These estimators exploit both signal and data
level redundant information to improve the estimation performance. The proposed
MLEs reduce to traditional fusion based or diversity based estimators when
communications or observations are perfect. By introducing a general message
function, the proposed estimators can be applied when various analog or digital
transmission schemes are used. The simulations show that the estimators using
digital communications with multiple-bit quantization outperform the estimator
using analog-and-forwarding transmission in fading channels. When considering
the total bandwidth and energy constraints, the MLE using multiple-bit
quantization is superior to that using binary quantization at medium and high
observation signal-to-noise ratio levels
Intraspecific variation in M1 enamel development in modern humans: implications for human evolution
The timing and sequence of enamel development, as well as enamel thickness, was documented for individual cusps (protoconid, hypoconid,metaconid, entoconid) in 15 unworn permanent lower first molars (M1s) from a sample of modern human juveniles. These data were compared with previously published data for modern and fossil species reported in the literature.
Crown formation in all teeth was initiated in the protoconid and completed in the hypoconid. These cusps had significantly longer formation times (2.91 and 2.96 yrs, respectively) than the metaconid and entoconid (2.52 and 2.38 yrs, respectively), as well as thicker enamel, and each represented between 92e95% of the total crown formation time. Rates of enamel secretion in all cusps increased significantly from 2.97 mm in the inner enamel to 4.47 mm in the outer enamel. Two cusps of one individual were studied in more detail and did not follow this typical trajectory. Rather, there was a sharp decrease in the middle of enamel formation and then a slow recovery of secretion rates from the mid to outer enamel. This anomalous trajectory of enamel formation is discussed in the context of other nondental tissue responses to illness. Neither secretion rates nor periodicity differed significantly when compared between the cusps of each molar. Differences in cusp formation times, initiation, and completion suggest a relationship between the rates of enamel formation and enamel thickness. This fits with expectations about the mechanics of the chewing cycle and general lower molar morphology. A comparison with similar
data for some nonhuman primates and fossil hominoids suggests this relationship may hold true across several primate taxa. Other aspects of enamel growth differed between this human sample and certain fossil species. The lower molars formed slowly over a longer period of time,
which may reflect the extended growth period of modern humans. The methodological approach adopted in this study is discussed in the context of that used in other studies
Optical antennas and plasmonics
Optical antenna is a nanoscale miniaturization of radio or microwave antennas
that is also governed by the rule of plasmonics. We introduce various types of
optical antenna and make an overview of recent developments in optical antenna
research. The role of local and surface plasmons in optical antenna is
explained through antenna resonance and resonance conditions for specific metal
structures are explicitly obtained. Strong electric field is shown to exist
within a highly localized region of optical antennas such as antenna feed gap
or apertures. We describe physical properties of field enhancement in
apertures(circular and rectangular holes) and gaps(infinite slit and feed gap),
as well as experimental techniques measuring enhanced electric vector field. We
discuss about analogies and differences between conventional and optical
antennas with a projection of future developments.Comment: To be published in Contemporary Physic
Gas and Star Formation in the Circinus Galaxy
We present a detailed study of the Circinus Galaxy, investigating its star
formation, dust and gas properties both in the inner and outer disk. To achieve
this, we obtained high-resolution Spitzer mid-infrared images with the IRAC
(3.6, 5.8, 4.5, 8.0 micron) and MIPS (24 and 70 micron) instruments and
sensitive HI data from the Australia Telescope Compact Array (ATCA) and the
64-m Parkes telescope. These were supplemented by CO maps from the Swedish-ESO
Submillimetre Telescope (SEST). Because Circinus is hidden behind the Galactic
Plane, we demonstrate the careful removal of foreground stars as well as large-
and small-scale Galactic emission from the Spitzer images. We derive a visual
extinction of Av = 2.1 mag from the Spectral Energy Distribution of the
Circinus Galaxy and total stellar and gas masses of 9.5 x 10^{10} Msun and 9 x
10^9 Msun, respectively. Using various wavelength calibrations, we find
obscured global star formation rates between 3 and 8 Msun yr^{-1}. Star forming
regions in the inner spiral arms of Circinus, which are rich in HI, are
beautifully unveiled in the Spitzer 8 micron image. The latter is dominated by
polycyclic aromatic hydrocarbon (PAH) emission from heated interstellar dust.
We find a good correlation between the 8 micron emission in the arms and
regions of dense HI gas. The (PAH 8 micron) / 24 micron surface brightness
ratio shows significant variations across the disk of Circinus.Comment: 18 pages, 14 figures. All figures have been compressed. Contact
authors for original figures. Accepted by MNRA
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