316 research outputs found
Berberine Improves Glucose Metabolism in Diabetic Rats by Inhibition of Hepatic Gluconeogenesis
Berberine (BBR) is a compound originally identified in a Chinese herbal medicine Huanglian (Coptis chinensis French). It improves glucose metabolism in type 2 diabetic patients. The mechanisms involve in activation of adenosine monophosphate activated protein kinase (AMPK) and improvement of insulin sensitivity. However, it is not clear if BBR reduces blood glucose through other mechanism. In this study, we addressed this issue by examining liver response to BBR in diabetic rats, in which hyperglycemia was induced in Sprague-Dawley rats by high fat diet. We observed that BBR decreased fasting glucose significantly. Gluconeogenic genes, Phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase), were decreased in liver by BBR. Hepatic steatosis was also reduced by BBR and expression of fatty acid synthase (FAS) was inhibited in liver. Activities of transcription factors including Forkhead transcription factor O1 (FoxO1), sterol regulatory element-binding protein 1c (SREBP1) and carbohydrate responsive element-binding protein (ChREBP) were decreased. Insulin signaling pathway was not altered in the liver. In cultured hepatocytes, BBR inhibited oxygen consumption and reduced intracellular adenosine triphosphate (ATP) level. The data suggest that BBR improves fasting blood glucose by direct inhibition of gluconeogenesis in liver. This activity is not dependent on insulin action. The gluconeogenic inhibition is likely a result of mitochondria inhibition by BBR. The observation supports that BBR improves glucose metabolism through an insulin-independent pathway
Azimuthal anisotropy of neutral pion production in Au+Au collisions at sqrt(s_NN) = 200 GeV: Path-length dependence of jet quenching and the role of initial geometry
We have measured the azimuthal anisotropy of pi0's for 1 < pT < 18 GeV/c for
Au+Au collisions at sqrt s_NN = 200 GeV. The observed anisotropy shows a
gradual decrease in 3 < pT < 7 - 10 GeV/c, but remains positive beyond 10
GeV/c. The magnitude of this anisotropy is under-predicted, up to at least 10
GeV/c, by current perturbative QCD (pQCD) energy-loss model calculations. An
estimate of the increase in anisotropy expected from initial-geometry
modification due to gluon saturation effects and initial-geometry fluctuations
is insufficient to account for this discrepancy. Calculations which implement a
path length dependence steeper than what is implied by current pQCD energy-loss
models, show reasonable agreement with the data.Comment: 384 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Cold Nuclear Matter Effects on J/psi Yields as a Function of Rapidity and Nuclear Geometry in Deuteron-Gold Collisions at sqrt(s_NN) = 200 GeV
We present measurements of J/psi yields in d+Au collisions at sqrt(s_NN) =
200 GeV recorded by the PHENIX experiment and compare with yields in p+p
collisions at the same energy per nucleon-nucleon collision. The measurements
cover a large kinematic range in J/psi rapidity (-2.2 < y < 2.4) with high
statistical precision and are compared with two theoretical models: one with
nuclear shadowing combined with final state breakup and one with coherent gluon
saturation effects. To remove model dependent systematic uncertainties we also
compare the data to a simple geometric model. We find that calculations where
the nuclear modification is linear or exponential in the density weighted
longitudinal thickness are difficult to reconcile with the forward rapidity
data.Comment: 449 authors from 66 institutions, 6 pages, 3 figures. Submitted to
Physical Review Letters. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (or will be) publicly
available at http://www.phenix.bnl.gov/papers.htm
Transverse momentum dependence of J/psi polarization at midrapidity in p+p collisions at sqrt(s)=200 GeV
We report the measurement of the transverse momentum dependence of inclusive
J/psi polarization in p+p collisions at sqrt(s)=200 GeV performed by the PHENIX
Experiment at RHIC. The polarization is studied in the helicity,
Gottfried-Jackson, and Collins-Soper frames for p_T < 5 GeV/c and |y| < 0.35.
The J/psi polarization in the helicity and Gottfried-Jackson frames is
consistent with zero for all transverse momenta, with a slight (1.8 sigma)
trend towards longitudinal polarization for transverse momenta above 2 GeV/c.
No conclusion is allowed due to the limited acceptance in the Collins-Soper
frame and the uncertainties of the current data. The results are compared to
observations for other collision systems and center of mass energies and to
different quarkonia production models.Comment: 384 authors from 62 institutions, 11 pages, 9 figures, 2 tables. v2
is expanded version submitted to Physical Review D. Plain text data tables
for the points plotted in figures are available at
http://www.phenix.bnl.gov/papers.htm
High p_T Direct Photon and pi^0 Triggered Azimuthal Jet Correlations in sqrt(s)=200 GeV p+p Collisions
Correlations of charged hadrons of 1 < pT < 10 GeV/c with high pT direct
photons and pi^ 0 mesons in the range 5 <pT < 15 GeV/c are used to study jet
fragmentation in the photon+jet and di-jet channels, respectively. The
magnitude of the partonic transverse momentum, kT, is obtained by comparing to
a model incorporating a Gaussian kT smearing. The sensitivity of the associated
charged hadron spectra to the underlying fragmentation function is tested and
the data are compared to calculations using recent global fit results. The
shape of the direct photon-associated hadron spectrum as well as its charge
asymmetry are found to be consistent with a sample dominated by quark-gluon
Compton scattering. No significant evidence of fragmentation photon correlated
production is observed within experimental uncertainties.Comment: 431 authors, 18 pages, 18 figures, 4 tables, RevTeX-4. Submitted to
Physical Review D. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter
Azimuthal angle \Delta\phi correlations are presented for charged hadrons
from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200
GeV. With increasing p_T, the away-side distribution evolves from a broad to a
concave shape, then to a convex shape. Comparisons to p+p data suggest that the
away-side can be divided into a partially suppressed "head" region centered at
Delta\phi ~ \pi, and an enhanced "shoulder" region centered at Delta\phi ~ \pi
+/- 1.1. The p_T spectrum for the "head" region softens toward central
collisions, consistent with the onset of jet quenching. The spectral slope for
the "shoulder" region is independent of centrality and trigger p_T, which
offers constraints on energy transport mechanisms and suggests that the
"shoulder" region contains the medium response to energetic jets.Comment: 420 authors from 58 institutions, 6 pages, 4 figures. Submitted to
Physical Review Letters. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (or will be) publicly
available at http://www.phenix.bnl.gov/papers.htm
Cold Nuclear Matter Effects on J/Psi as Constrained by Deuteron-Gold Measurements at sqrt(s_NN) = 200 GeV
We present a new analysis of J/psi production yields in deuteron-gold
collisions at sqrt(s_NN) = 200 GeV using data taken by the PHENIX experiment in
2003 and previously published in [S.S. Adler et al., Phys. Rev. Lett 96, 012304
(2006)]. The high statistics proton-proton J/psi data taken in 2005 is used to
improve the baseline measurement and thus construct updated cold nuclear matter
modification factors R_dAu. A suppression of J/psi in cold nuclear matter is
observed as one goes forward in rapidity (in the deuteron-going direction),
corresponding to a region more sensitive to initial state low-x gluons in the
gold nucleus. The measured nuclear modification factors are compared to
theoretical calculations of nuclear shadowing to which a J/psi (or precursor)
break-up cross-section is added. Breakup cross sections of sigma_breakup =
2.8^[+1.7_-1.4] (2.2^[+1.6_-1.5]) mb are obtained by fitting these calculations
to the data using two different models of nuclear shadowing. These breakup
cross section values are consistent within large uncertainties with the 4.2 +/-
0.5 mb determined at lower collision energies. Projecting this range of cold
nuclear matter effects to copper-copper and gold-gold collisions reveals that
the current constraints are not sufficient to firmly quantify the additional
hot nuclear matter effect.Comment: 453 authors from 59 institutions, 15 pages, 13 figures, 5 tables.
Submitted to Physical Review C. Plain text data tables for the points plotted
in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
Emerging IT risks: insights from German banking
How do German banks manage the emerging risks stemming from IT innovations such as cyber risk? With a focus on process, roles and responsibilities, field data from ten banks participating in the 2014 ECB stress test were collected by interviewing IT managers, risk managers and external experts. Current procedures for handling emerging risks in German banks were identified from the interviews and analysed, guided by the extant literature. A clear gap was found between enterprise risk management (ERM) as a general approach to risks threatening firms’ objectives and ERM’s neglect of emerging risks, such as those associated with IT innovations. The findings suggest that ERM should be extended towards the collection and sharing of knowledge to allow for an initial understanding and description of emerging risks, as opposed to the traditional ERM approach involving estimates of impact and probability. For example, as cyber risks emerge from an IT innovation, the focus may need to switch towards reducing uncertainty through knowledge acquisition. Since individual managers seldom possess all relevant knowledge of an IT innovation, various stakeholders may need to be involved to exploit their expertise
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Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV
The momentum distribution of electrons from semi-leptonic decays of charm and
bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is
measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC)
over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of
electrons from bottom to that from charm is presented. The ratio is determined
using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It
is found that the yield of electrons from bottom becomes significant above 4
GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative
quantum chromodynamics (pQCD) calculation agrees with the data within the
theoretical and experimental uncertainties. The extracted total bottom
production cross section at this energy is \sigma_{b\b^bar}= 3.2
^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
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