3,647 research outputs found
The use of MHC class I or class II 'knock out' mice to investigate the role of these antigens in allosensitization
Flavonoid intake and the risk of age-related cataract in China’s Heilongjiang Province
Background/Objectives: Epidemiological evidence suggests that diets rich in flavonoids may reduce the risk of developing age-related cataract (ARC). Flavonoids are widely distributed in foods of plant origin and the objective of this study was to evaluate retrospectively the association between the intakes of the five flavonoid subclasses and the risk of ARC. Subjects/Methods: A population-based case-control study (249 cases and 66 controls) was carried out in Heilongjiang province, which is located in the Northeast of China, and where intakes and availability of fresh vegetables and fruits can be limited. Dietary data gathered by food-frequency questionnaire (FFQ) were used to calculate flavonoid intake. Adjusted odds ratio (OR) and 95% confidence interval (CI) were estimated by logistic regression. Results: No linear associations between risk of developing ARC and intakes of total dietary flavonoids, anthocyanidins, flavon-3-ol, flavanone, total flavones or total flavonols were found, but quercetin and isorhamnetin intake was inversely associated with ARC risk (OR 11.78, 95% CI: 1.62-85.84, P<0.05, and OR 6.99, 95% CI:1.12-43.44, P<0.05, quartile 4 vs quartile 1, respectively). Conclusion: As quercetin is contained in many plant foods and isorhamnetin is only contained in very few foods, we concluded that higher quercetin intake may be an important dietary factor in the reduction of risk of age-related cataract
Diffuse Gamma Rays: Galactic and Extragalactic Diffuse Emission
"Diffuse" gamma rays consist of several components: truly diffuse emission
from the interstellar medium, the extragalactic background, whose origin is not
firmly established yet, and the contribution from unresolved and faint Galactic
point sources. One approach to unravel these components is to study the diffuse
emission from the interstellar medium, which traces the interactions of high
energy particles with interstellar gas and radiation fields. Because of its
origin such emission is potentially able to reveal much about the sources and
propagation of cosmic rays. The extragalactic background, if reliably
determined, can be used in cosmological and blazar studies. Studying the
derived "average" spectrum of faint Galactic sources may be able to give a clue
to the nature of the emitting objects.Comment: 32 pages, 28 figures, kapproc.cls. Chapter to the book "Cosmic
Gamma-Ray Sources," to be published by Kluwer ASSL Series, Edited by K. S.
Cheng and G. E. Romero. More details can be found at
http://www.gamma.mpe-garching.mpg.de/~aws/aws.htm
The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)
This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The file attached is the published version of the article
Decaying Dark Matter in Supersymmetric Model and Cosmic-Ray Observations
We study cosmic-rays in decaying dark matter scenario, assuming that the dark
matter is the lightest superparticle and it decays through a R-parity violating
operator. We calculate the fluxes of cosmic-rays from the decay of the dark
matter and those from the standard astrophysical phenomena in the same
propagation model using the GALPROP package. We reevaluate the preferred
parameters characterizing standard astrophysical cosmic-ray sources with taking
account of the effects of dark matter decay. We show that, if energetic leptons
are produced by the decay of the dark matter, the fluxes of cosmic-ray positron
and electron can be in good agreements with both PAMELA and Fermi-LAT data in
wide parameter region. It is also discussed that, in the case where sizable
number of hadrons are also produced by the decay of the dark matter, the mass
of the dark matter is constrained to be less than 200-300 GeV in order to avoid
the overproduction of anti-proton. We also show that the cosmic gamma-ray flux
can be consistent with the results of Fermi-LAT observation if the mass of the
dark matter is smaller than nearly 4 TeV.Comment: 24 pages, 5 figure
Wacker-oxidation of Ethylene over Pillared Layered Material Catalysts
This paper concerns the Wacker oxidation of ethylene by oxygen in the presence of water over supported Pd/VOx catalysts. High surface area porous supports were obtained from layer-structured materials, such as, montmorillonite (MT), laponite (LT) (smectites), and hydrotalcite (layered double hydroxide, LDH) by pillaring. Before introduction of Pd, supports MT and LDH were pillared by vanadia. The laponite was used in titania-pillared form (TiO2-LAP) as support of Pd/VOx active component. Acetaldehyde (AcH), acetic acid (AcOH) and CO2 were the products with yields and selectivities, depending on the reaction conditions and the properties of the applied catalyst. Under comparable conditions the pillared smectite catalysts gave higher AcH yield than the pillared LDH catalyst. UV vis spectroscopic examination suggested that the pillared smectites contained polymeric chains of VO4, whereas only isolated monomeric VO4 species were present in the pillared LDH. The higher catalytic activity in the Wacker oxidation was attributed to the more favorable redox property of the polymeric than of the monomeric vanadia. The V3+ ions in the polymeric species can reduce O2 to O2- ions, whereas the obtained V5+ ions are ready to pass over O to Pd0 to generate PdO whereon the oxidation of the ethylene proceeds
Analogue peptides for the immunotherapy of human acute myeloid leukemia
Accepted manuscript. The final publication is available at: http://link.springer.com/article/10.1007%2Fs00262-015-1762-9The use of peptide vaccines, enhanced by adjuvants, has shown some efficacy in clinical trials. However, responses are often short-lived and rarely induce notable memory responses. The reason is that self-antigens have already been presented to the immune system as the tumor develops, leading to tolerance or some degree of host tumor cell destruction. To try to break tolerance against self-antigens, one of the methods employed has been to modify peptides at the anchor residues to enhance their ability to bind major histocompatibility complex molecules, extending their exposure to the T-cell receptor. These modified or analogue peptides have been investigated as stimulators of the immune system in patients with different cancers with variable but sometimes notable success. In this review we describe the background and recent developments in the use of analogue peptides for the immunotherapy of acute myeloid leukemia describing knowledge useful for the application of analogue peptide treatments for other malignancies
The holographic principle
There is strong evidence that the area of any surface limits the information
content of adjacent spacetime regions, at 10^(69) bits per square meter. We
review the developments that have led to the recognition of this entropy bound,
placing special emphasis on the quantum properties of black holes. The
construction of light-sheets, which associate relevant spacetime regions to any
given surface, is discussed in detail. We explain how the bound is tested and
demonstrate its validity in a wide range of examples.
A universal relation between geometry and information is thus uncovered. It
has yet to be explained. The holographic principle asserts that its origin must
lie in the number of fundamental degrees of freedom involved in a unified
description of spacetime and matter. It must be manifest in an underlying
quantum theory of gravity. We survey some successes and challenges in
implementing the holographic principle.Comment: 52 pages, 10 figures, invited review for Rev. Mod. Phys; v2:
reference adde
The stellar halo of the Galaxy
Stellar halos may hold some of the best preserved fossils of the formation
history of galaxies. They are a natural product of the merging processes that
probably take place during the assembly of a galaxy, and hence may well be the
most ubiquitous component of galaxies, independently of their Hubble type. This
review focuses on our current understanding of the spatial structure, the
kinematics and chemistry of halo stars in the Milky Way. In recent years, we
have experienced a change in paradigm thanks to the discovery of large amounts
of substructure, especially in the outer halo. I discuss the implications of
the currently available observational constraints and fold them into several
possible formation scenarios. Unraveling the formation of the Galactic halo
will be possible in the near future through a combination of large wide field
photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes.
Full-resolution version available at
http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd
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