135 research outputs found
Measurement of the Neutron Radius of 208Pb Through Parity-Violation in Electron Scattering
We report the first measurement of the parity-violating asymmetry A_PV in the
elastic scattering of polarized electrons from 208Pb. A_PV is sensitive to the
radius of the neutron distribution (Rn). The result A_PV = 0.656 \pm 0.060
(stat) \pm 0.014 (syst) ppm corresponds to a difference between the radii of
the neutron and proton distributions Rn - Rp = 0.33 +0.16 -0.18 fm and provides
the first electroweak observation of the neutron skin which is expected in a
heavy, neutron-rich nucleus.Comment: 6 pages, 1 figur
Electroexcitation of the at low momentum transfer
We report on new p measurements at the
resonance at the low momentum transfer region. The mesonic
cloud dynamics is predicted to be dominant and rapidly changing in this
kinematic region offering a test bed for chiral effective field theory
calculations. The new data explore the low dependence of the resonant
quadrupole amplitudes while extending the measurements of the Coulomb
quadrupole amplitude to the lowest momentum transfer ever reached. The results
disagree with predictions of constituent quark models and are in reasonable
agreement with dynamical calculations that include pion cloud effects, chiral
effective field theory and lattice calculations. The reported measurements
suggest that improvement is required to the theoretical calculations and
provide valuable input that will allow their refinements
Liver-Specific Deletion of Protein-Tyrosine Phosphatase 1B (PTP1B) Improves Metabolic Syndrome and Attenuates Diet-Induced Endoplasmic Reticulum Stress
OBJECTIVE—The protein tyrosine phosphatase PTP1B is a negative regulator of insulin signaling; consequently, mice deficient in PTP1B are hypersensitive to insulin. Because PTP1B−/− mice have diminished fat stores, the extent to which PTP1B directly regulates glucose homeostasis is unclear. Previously, we showed that brain-specific PTP1B−/− mice are protected against high-fat diet–induced obesity and glucose intolerance, whereas muscle-specific PTP1B−/− mice have increased insulin sensitivity independent of changes in adiposity. Here we studied the role of liver PTP1B in glucose homeostasis and lipid metabolism
Uncovering the Importance of Selenium in Muscle Disease
A connection between selenium bioavailability and development of muscular
disorders both in humans and livestock has been established for a long time.
With the development of genomics, the function of several selenoproteins was
shown to be involved in muscle activity, including SELENON, which was linked to
an inherited form of myopathy. Development of animal models has helped to dissect
the physiological dysfunction due to mutation in the SELENON gene; however the
molecular activity remains elusive and only recent analysis using both in vivo and
in vitro experiment provided hints toward its function in oxidative stress defence
and calcium transport control. This review sets out to summarise most recent findings
for the importance of selenium in muscle function and the contribution of this
information to the design of strategies to cure the diseases
Histone deacetylase inhibitors: potential targets responsible for their anti-cancer effect
The histone deacetylase inhibitors (HDACi) have demonstrated anticancer efficacy across a range of malignancies, most impressively in the hematological cancers. It is uncertain whether this clinical efficacy is attributable predominantly to their ability to induce apoptosis and differentiation in the cancer cell, or to their ability to prime the cell to other pro-death stimuli such as those from the immune system. HDACi-induced apoptosis occurs through altered expression of genes encoding proteins in both intrinsic and extrinsic apoptotic pathways; through effects on the proteasome/aggresome systems; through the production of reactive oxygen species, possibly by directly inducing DNA damage; and through alterations in the tumor microenvironment. In addition HDACi increase the immunogenicity of tumor cells and modulate cytokine signaling and potentially T-cell polarization in ways that may contribute the anti-cancer effect in vivo. Here, we provide an overview of current thinking on the mechanisms of HDACi activity, with attention given to the hematological malignancies as well as scientific observations arising from the clinical trials. We also focus on the immune effects of these agents
Search for three-nucleon short-range correlations in light nuclei
We present new data probing short-range correlations (SRCs) in nuclei through the measurement of electron scattering off high-momentum nucleons in nuclei. The inclusive ^{4}He/^{3}He cross section ratio is observed to be both x and Q^{2} independent for 1.52, our data support the hypothesis that a previous claim of three-nucleon correlation dominance was an artifact caused by the limited resolution of the measurement. While 3N-SRCs appear to have an important contribution, our data show that isolating 3N-SRCs is significantly more complicated than for 2N-SRCs.United States. Department of Energy (Contract DE-AC05-06OR23177)United States. Department of Energy (Contract DE-AC02-06CH11357)United States. Department of Energy (Contract DE-FG02-96ER40950
Probing the Repulsive Core of the Nucleon-Nucleon Interaction via the 4He(e,e'pN) Triple-Coincidence Reaction
We studied simultaneously the 4He(e,e'p), 4He(e,e'pp), and 4He(e,e'pn)
reactions at Q^2=2 [GeV/c]2 and x_B>1, for a (e,e'p) missing-momentum range of
400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a
proton or neutron recoiling almost back to back to the missing momentum,
leaving the residual A=2 system at low excitation energy. These data were used
to identify two-nucleon short-range correlated pairs and to deduce their
isospin structure as a function of missing momentum in a region where the
nucleon-nucleon force is expected to change from predominantly tensor to
repulsive. Neutron-proton pairs dominate the high-momentum tail of the nucleon
momentum distributions, but their abundance is reduced as the nucleon momentum
increases beyond ~500 MeV/c. The extracted fraction of proton-proton pairs is
small and almost independent of the missing momentum in the range we studied.
Our data are compared with ab-initio calculations of two-nucleon momentum
distributions in 4He.Comment: 6 pages, 2 figure
Targeting Huntington’s disease through histone deacetylases
Huntington’s disease (HD) is a debilitating neurodegenerative condition with significant burdens on both patient and healthcare costs. Despite extensive research, treatment options for patients with this condition remain limited. Aberrant post-translational modification (PTM) of proteins is emerging as an important element in the pathogenesis of HD. These PTMs include acetylation, phosphorylation, methylation, sumoylation and ubiquitination. Several families of proteins are involved with the regulation of these PTMs. In this review, I discuss the current evidence linking aberrant PTMs and/or aberrant regulation of the cellular machinery regulating these PTMs to HD pathogenesis. Finally, I discuss the evidence suggesting that pharmacologically targeting one of these protein families the histone deacetylases may be of potential therapeutic benefit in the treatment of HD
Comparative analysis of metazoan chromatin organization
Genome function is dynamically regulated in part by chromatin, which consists of the histones, non-histone proteins and RNA molecules that package DNA. Studies in Caenorhabditis elegans and Drosoph ..
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