1,303 research outputs found
Synergistic effect of phosphodiesterase 4 inhibitor and serum on migration of endotoxin-stimulated macrophages.
Macrophage migration is an essential step in host defense against infection and wound healing. Elevation of cAMP by inhibiting phosphodiesterase 4 (PDE4), enzymes that specifically degrade cAMP, is known to suppress various inflammatory responses in activated macrophages, but the role of PDE4 in macrophage migration is poorly understood. Here we show that the migration of Raw 264.7 macrophages stimulated with LPS was markedly and dose-dependently induced by the PDE4 inhibitor rolipram as assessed by scratch wound healing assay. Additionally, this response required the involvement of serum in the culture medium as serum starvation abrogated the effect. Further analysis revealed that rolipram and serum exhibited synergistic effect on the migration, and the influence of serum was independent of PDE4 mRNA expression in LPS-stimulated macrophages. Moreover, the enhanced migration by rolipram was mediated by activating cAMP/exchange proteins directly activated by cAMP (Epac) signaling, presumably via interaction with LPS/TLR4 signaling with the participation of unknown serum components. These results suggest that PDE4 inhibitors, together with serum components, may serve as positive regulators of macrophage recruitment for more efficient pathogen clearance and wound repair
Subtracted Dispersion Relations for In-Medium Meson Correlators in QCD Sum Rules
We analyze subtracted dispersion relations for meson correlators at finite
baryon density and temperature. Such relations are needed for QCD sum rules. We
point out the importance of scattering terms, as well as finite, well-defined
subtraction constants. Both are necessary for consistency, in particular for
the equality of the longitudinal and transverse correlators in the limit of the
vanishing three-momentum of mesons relative to the medium. We present detailed
calculations in various mesonic channels for the case of the Fermi gas of
nucleons
Indoxyl Sulfate-Induced Oxidative Stress, Mitochondrial Dysfunction, and Impaired Biogenesis Are Partly Protected by Vitamin C and N-Acetylcysteine
Indoxyl sulfate (IS) contributes to oxidative stress and endothelial dysfunction in chronic kidney disease patients. However, the role of mitochondria in IS-induced oxidative stress is not very clear. In this study, we examined whether mitochondria play a pivotal role in modulating the effects of antioxidants during IS treatment. In the context of human umbilical vein endothelial cells, we found that IS had a dose-dependent antiproliferative effect. In addition, we used flow cytometry to demonstrate that the level of reactive oxygen species increased in a dose-dependent manner after treatment with IS. High doses of IS also corresponded to increased mitochondrial depolarization and decreased mitochondrial DNA copy number and mitochondrial mass. However, these effects could be reversed by the addition of antioxidants, namely, vitamin C and N-acetylcysteine. Thus, our results suggest that IS-induced oxidative stress and antiproliferative effect can be attributed to mitochondrial dysfunction and impaired biogenesis and that these processes can be protected by treatment with antioxidants
Zigzag magnetic order in a novel tellurate compound NaNiTeO with = 1 chains
NaNiTeO is a rare example in the transition-metal
tellurate family of realizing an = 1 spin-chain structure. By performing
neutron powder diffraction measurements, the ground-state magnetic structure of
NaNiTeO is determined. These measurements reveal that below
6.8(2) K, the Ni moments form a screwed
ferromagnetic (FM) spin-chain structure running along the crystallographic
axis but these FM spin chains are coupled antiferromagnetically along the
and directions, giving rise to a magnetic propagation vector of = (0,
1/2, 1/2). This zigzag magnetic order is well supported by first-principles
calculations. The moment size of Ni spins is determined to be 2.1(1)
at 3 K, suggesting a significant quenching of the orbital moment
due to the crystalline electric field (CEF) effect. The previously reported
metamagnetic transition near 0.1 T can be understood as a
field-induced spin-flip transition. The relatively easy tunability of the
dimensionality of its magnetism by external parameters makes
NaNiTeO a promising candidate for further exploring various
types of novel spin-chain physics.Comment: 10 pages, 6 figure
Seeing phi meson through the dilepton spectra in heavy-ion collisions
Dilepton spectra from the decay of phi mesons produced in heavy-ion
collisions at SIS/GSI energies ( GeV/nucleon) are studied in the
relativistic transport model. We include phi mesons produced from
baryon-baryon, pion-baryon, and kaon-antikaon collisions. The cross sections
for the first two processes are obtained from an one-boson-exchange model,
while that for the last process is taken to be the Breit-Wigner form through
the phi meson resonance. For dileptons with invariant mass near the phi meson
peak, we also include contributions from neutron-proton bremsstrahlung,
pion-pion annihilation, and the decay of rho and omega mesons produced in
baryon-baryon and meson-baryon collisions. Effects due to medium modifications
of the kaon and vector (rho, omega and phi) meson properties are investigated.
We find that the kaon medium effects lead to a broadening of the dilepton
spectrum as a result of the increase of phi meson decay width. Furthermore, the
dropping of phi meson mass in nuclear medium leads to a shoulder structure in
the dilepton spectrum besides the main peak at the bare phi meson mass. The
experimental measurement of the dilepton spectra from heavy-ion collisions is
expected to provide useful information about the phi meson properties in dense
matter.Comment: RevTeX, 18 pages, including 13 postscript figures, submitted to
Nuclear Physics
OpenIllumination: A Multi-Illumination Dataset for Inverse Rendering Evaluation on Real Objects
We introduce OpenIllumination, a real-world dataset containing over 108K
images of 64 objects with diverse materials, captured under 72 camera views and
a large number of different illuminations. For each image in the dataset, we
provide accurate camera parameters, illumination ground truth, and foreground
segmentation masks. Our dataset enables the quantitative evaluation of most
inverse rendering and material decomposition methods for real objects. We
examine several state-of-the-art inverse rendering methods on our dataset and
compare their performances. The dataset and code can be found on the project
page: https://oppo-us-research.github.io/OpenIllumination
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