5,097 research outputs found
Globally Polarized Quark-gluon Plasma in Non-central A+A Collisions
Produced partons have large local relative orbital angular momentum along the
direction opposite to the reaction plane in the early stage of non-central
heavy-ion collisions. Parton scattering is shown to polarize quarks along the
same direction due to spin-orbital coupling. Such global quark polarization
will lead to many observable consequences, such as left-right asymmetry of
hadron spectra, global transverse polarization of thermal photons, dileptons
and hadrons. Hadrons from the decay of polarized resonances will have azimuthal
asymmetry similar to the elliptic flow. Global hyperon polarization is
predicted within different hadronization scenarios and can be easily tested.Comment: 4 pages in RevTex with 2 postscript figures, an erratum is added to
the final published versio
Interethnic differences in pancreatic cancer incidence and risk factors: The Multiethnic Cohort.
While disparity in pancreatic cancer incidence between blacks and whites has been observed, few studies have examined disparity in other ethnic minorities. We evaluated variations in pancreatic cancer incidence and assessed the extent to which known risk factors account for differences in pancreatic cancer risk among African Americans, Native Hawaiians, Japanese Americans, Latino Americans, and European Americans in the Multiethnic Cohort Study. Risk factor data were obtained from the baseline questionnaire. Cox regression was used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for pancreatic cancer associated with risk factors and ethnicity. During an average 16.9-year follow-up, 1,532 incident pancreatic cancer cases were identified among 184,559 at-risk participants. Family history of pancreatic cancer (RR 1.97, 95% CI 1.50-2.58), diabetes (RR 1.32, 95% CI 1.14-1.54), body mass index ≥30 kg/m2 (RR 1.25, 95% CI 1.08-1.46), current smoking (<20 pack-years RR 1.43, 95% CI 1.19-1.73; ≥20 pack-years RR 1.76, 95% CI 1.46-2.12), and red meat intake (RR 1.17, 95% CI 1.00-1.36) were associated with pancreatic cancer. After adjustment for these risk factors, Native Hawaiians (RR 1.60, 95% CI 1.30-1.98), Japanese Americans (RR 1.33, 95% CI 1.15-1.54), and African Americans (RR 1.20, 95% CI 1.01-1.42), but not Latino Americans (RR 0.90, 95% CI 0.76-1.07), had a higher risk of pancreatic cancer compared to European Americans. Interethnic differences in pancreatic cancer risk are not fully explained by differences in the distribution of known risk factors. The greater risks in Native Hawaiians and Japanese Americans are new findings and elucidating the causes of these high rates may improve our understanding and prevention of pancreatic cancer
Temperature dependence of single-particle properties in nuclear matter
The single-nucleon potential in hot nuclear matter is investigated in the
framework of the Brueckner theory by adopting the realistic Argonne V18 or
Nijmegen 93 two-body nucleon-nucleon interaction supplemented by a microscopic
three-body force. The rearrangement contribution to the single-particle
potential induced by the ground state correlations is calculated in terms of
the hole-line expansion of the mass operator and provides a significant
repulsive contribution in the low-momentum region around and below the Fermi
surface. Increasing temperature leads to a reduction of the effect, while
increasing density makes it become stronger. The three-body force suppresses
somewhat the ground state correlations due to its strong short-range repulsion,
increasing with density. Inclusion of the three-body force contribution results
in a quite different temperature dependence of the single-particle potential at
high enough densities as compared to that adopting the pure two-body force. The
effects of three-body force and ground state correlations on the nucleon
effective mass are also discussed.Comment: 14 pages, 5 figure
Correlation effects in the ground state charge density of Mott-insulating NiO: a comparison of ab-initio calculations and high-energy electron diffraction measurements
Accurate high-energy electron diffraction measurements of structure factors
of NiO have been carried out to investigate how strong correlations in the Ni
3d shell affect electron charge density in the interior area of nickel ions and
whether the new ab-initio approaches to the electronic structure of strongly
correlated metal oxides are in accord with experimental observations. The
generalized gradient approximation (GGA) and the local spin density
approximation corrected by the Hubbard U term (LSDA+U) are found to provide the
closest match to experimental measurements. The comparison of calculated and
observed electron charge densities shows that correlations in the Ni 3d shell
suppress covalent bonding between the oxygen and nickel sublattices.Comment: 6 pages, LaTeX and 5 figures in the postscript forma
Pectolinarigenin - A Flavonoid Compound from Cirsium Japonicum with Potential Anti-proliferation Activity in MCF- 7 Breast Cancer Cell
Purpose: To isolate high purity pectolinarigenin from Cirsium japonicum and evaluates its antiproliferative potential and induction of apoptosis activity in MCF-7 breast cancer cell.Methods: Pectolinarigenin was purified by the combination of silica gel and Sephadex LH-20 column chromatography. The structure was identified by 1H-nuclear magnetic resonance (NMR), 13C-NMR and electrospray ionization tandem mass spectrometry (ESI-MS) analyses. The anti-proliferation activity of pectolinarigenin was also evaluated by methylthiazolyldiphenyl-tetrazolium bromide (MTT) and colony formation assays in MCF-7 breast cancer cell.Results: Pectolinarigenin showed potent anti-proliferation activity by inducing apoptosis and downregulation of Bcl2 expression in MCF-7 breast cancer cell. Protein expression of Bcl2 was almost completely inhibited upon the treatment with 25 ÎĽM pectolinarigenin.Conclusion: A rapid method to isolate high purity pectolinarigenin from C. japonicum and as well as evaluate its anti-proliferative potential and induction of apoptosis in MCF-7 breast cancer cells is presented for the first time. Induction of apoptosis of MCF-7 is via downregulation of Bcl2 expression.Keywords: Cirsium japonicum, Anti-proliferation activity, Pectolinarigenin, Breast cancer,Apoptosis
Evaluation of Apoptotic and Growth Inhibitory Activity of Phloretin in BGC823 Gastric Cancer Cell
Purpose: To evaluate the in vitro anti-proliferative activity and probable mechanism of phloretin in human gastric cancer BGC823 cell lines.Methods: Phloretin was isolated from apple tree leaves and identified by 1H-Nuclear Magnetic Resonance (NMR), 13C-NMR and electrospray ionization tandem mass spectrometry (ESI-MS). The inhibitory activity of the compound in BGC823 gastric cancer cells was determined by Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and soft agar colony formation assay while its apoptotic activity was detected by fluorescene staining and Western blotting analysis.Results: The results show that the inhibitory activity of phloretin in BGC823 gastric cancer cells was mediated by induction of apoptosis and down-regulation of Bcl2 (B-cell lymphoma 2) expression. The anti-proliferative effects of phloretin was dose-dependent and inhibited the growth of BGC823 gastric cancer cells by 73 % at 30 μM; this effectively induced cleavage of anti-poly (ADP-ribose) polymerase (PARP) as well as downregulation of Bcl2 protein expression in BGC823 cells after 24 h treatment.Conclusion: Phloretin is a promising preventive and therapeutic agent for gastric cancer.Keywords: Phloretin, Gastric cancer, Apoptosis, β-Cell lymphoma 2, Anti-poly (ADP ribose) polymeras
Accurate structure factors from pseudopotential methods
Highly accurate experimental structure factors of silicon are available in
the literature, and these provide the ideal test for any \emph{ab initio}
method for the construction of the all-electron charge density. In a recent
paper [J. R. Trail and D. M. Bird, Phys. Rev. B {\bf 60}, 7863 (1999)] a method
has been developed for obtaining an accurate all-electron charge density from a
first principles pseudopotential calculation by reconstructing the core region
of an atom of choice. Here this method is applied to bulk silicon, and
structure factors are derived and compared with experimental and Full-potential
Linear Augmented Plane Wave results (FLAPW). We also compare with the result of
assuming the core region is spherically symmetric, and with the result of
constructing a charge density from the pseudo-valence density + frozen core
electrons. Neither of these approximations provide accurate charge densities.
The aspherical reconstruction is found to be as accurate as FLAPW results, and
reproduces the residual error between the FLAPW and experimental results.Comment: 6 Pages, 3 figure
Recommended from our members
Does habitat stability structure intraspecific genetic diversity? It’s complicated...
Regional phylogeographic studies have long been conducted in the southeastern United States for a variety of species. With some exceptions, many of these studies focus on single species or single clades of organisms, and those considering multiple species tend to focus on deep historical breaks causing differentiation. However, in many species more recent factors may be influencing genetic diversity. To understand the roles of historic and contemporary processes in structuring genetic diversity, we reanalyzed existing genetic data from Southeast of North America using approaches gleaned from phylogeographic and landscape genetic literature that were implemented across species including AMOVAs, PCoAs, Species Distribution Modelling, and tests of isolation by distance, environment, and habitat instability. Genetic variance was significantly partitioned by ecoregions, watersheds, and across phylogeographic breaks in the majority of species. Similarly, genetic variation was significantly associated with some combination of geographic or environmental distance or habitat instability in most species. Patterns of genetic variation were largely idiosyncratic across species. While habitat instability over time is significantly correlated with genetic diversity in some species, it appears generally less important than isolation by geographic or environmental distance. Our results suggest that many factors, both historical and contemporary, impact genetic diversity within a species, and more so, that these patterns aren’t always similar in closely related species. This supports the importance of species- specific factors and cautions against assumptions that closely related species will respond to historical and contemporary forces in similar ways
- …