1,646 research outputs found
Circadian rhythm of hepatic cytosolic and nuclear estrogen receptors
The distribution of estrogen receptor between the cytosolic and nuclear compartments were evaluated in liver of male rats to determine whether a circadian rhythm exists. Cytosolic receptor reached a maximum level at 400 hours and a minimum at 2000 and 2400 hr. Nuclear receptor reached a maximum level at 800 hr and was lowest at 1600 and 2000 hr. Serum estradiol levels were also highest at 800 hr and lowest at 1600 hr. The variations in cytosolic and nuclear receptors are not reciprocal; in fact, the overall content of receptor in the liver is not constant and also displays a circadian rhythm. © 1986 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted
Evaluation of the ACS NSQIP Surgical Risk Calculator in Elderly Patients Undergoing Hepatectomy for Hepatocellular Carcinoma
Background: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) surgical risk calculator (SRC) aims to help predict patient-specific risk for morbidity and mortality. The performance of the SRC among an elderly population undergoing curative-intent hepatectomy for hepatocellular carcinoma (HCC) remains unknown.
Methods: Patients > 70 years of age who underwent hepatectomy for HCC between 1998 and 2017 were identified using a multi-institutional international database. To estimate the performance of SRC, 12 observed postoperative outcomes were compared with median SRC-predicted risk, and C-statistics and Brier scores were calculated.
Results: Among 500 patients, median age was 75 years (IQR 72-78). Most patients (n = 324, 64.8%) underwent a minor hepatectomy, while 35.2% underwent a major hepatectomy. The observed incidence of venous thromboembolism (VTE) (3.2%) and renal failure (RF) (4.4%) exceeded the median predicted risk (VTE, 1.8%; IQR 1.5-3.1 and RF, 1.0%; IQR 0.5-2.0). In contrast, the observed incidence of 30-day readmission (7.0%) and non-home discharge (2.5%) was lower than median-predicted risk (30-day readmission, 9.4%; IQR 7.4-12.8 and non-home discharge, 5.7%; IQR 3.3-11.7). Only 57.8% and 71.2% of patients who experienced readmission (C-statistic, 0.578; 95%CI 0.468-0.688) or mortality (C-statistic, 0.712; 95%CI 0.508-0.917) were correctly identified by the model.
Conclusion: Among elderly patients undergoing hepatectomy for HCC, the SRC underestimated the risk of complications such as VTE and RF, while being no better than chance in estimating the risk of readmission. The ACS SRC has limited clinical applicability in estimating perioperative risk among elderly patients being considered for hepatic resection of HCC.info:eu-repo/semantics/publishedVersio
Neutrino hierarchy from CP-blind observables with high density magnetized detectors
High density magnetized detectors are well suited to exploit the outstanding
purity and intensities of novel neutrino sources like Neutrino Factories and
Beta Beams. They can also provide independent measurements of leptonic mixing
parameters through the observation of atmospheric muon-neutrinos. In this
paper, we discuss the combination of these observables from a multi-kton iron
detector and a high energy Beta Beam; in particular, we demonstrate that even
with moderate detector granularities the neutrino mass hierarchy can be
determined for values greater than 4.Comment: 16 pages, 7 figures. Added a new section discussing systematic errors
(sec 5.2); sec.5.1 and 4 have been extended. Version to appear in EPJ
Measurement of Through-Going Particle Momentum By Means Of Multiple Scattering With The ICARUS T600 TPC
The ICARUS collaboration has demonstrated, following the operation of a 600
ton (T600) detector at shallow depth, that the technique based on liquid Argon
TPCs is now mature. The study of rare events, not contemplated in the Standard
Model, can greatly benefit from the use of this kind of detectors. In
particular, a deeper understanding of atmospheric neutrino properties will be
obtained thanks to the unprecedented quality of the data ICARUS provides.
However if we concentrate on the T600 performance, most of the
charged current sample will be partially contained, due to the reduced
dimensions of the detector. In this article, we address the problem of how well
we can determine the kinematics of events having partially contained tracks.
The analysis of a large sample of atmospheric muons collected during the T600
test run demonstrate that, in case the recorded track is at least one meter
long, the muon momentum can be reconstructed by an algorithm that measures the
Multiple Coulomb Scattering along the particle's path. Moreover, we show that
momentum resolution can be improved by a factor two using an algorithm based on
the Kalman Filtering technique
Measurement of the muon decay spectrum with the ICARUS liquid Argon TPC
Examples are given which prove the ICARUS detector quality through relevant
physics measurements. We study the muon decay energy spectrum from a sample of
stopping muon events acquired during the test run of the ICARUS T600 detector.
This detector allows the spatial reconstruction of the events with fine
granularity, hence, the precise measurement of the range and dE/dx of the muon
with high sampling rate. This information is used to compute the calibration
factors needed for the full calorimetric reconstruction of the events. The
Michel rho parameter is then measured by comparison of the experimental and
Monte Carlo simulated muon decay spectra, obtaining rho = 0.72 +/- 0.06(stat.)
+/- 0.08(syst.). The energy resolution for electrons below ~50 MeV is finally
extracted from the simulated sample, obtaining (Emeas-Emc)/Emc =
11%/sqrt(E[MeV]) + 2%.Comment: 16 pages, 8 figures, LaTex, A4. Some text and 1 figure added. Final
version as accepted for publication in The European Physical Journal
Search for anomalies in the neutrino sector with muon spectrometers and large LArTPC imaging detectors at CERN
A new experiment with an intense ~2 GeV neutrino beam at CERN SPS is proposed
in order to definitely clarify the possible existence of additional neutrino
states, as pointed out by neutrino calibration source experiments, reactor and
accelerator experiments and measure the corresponding oscillation parameters.
The experiment is based on two identical LAr-TPCs complemented by magnetized
spectrometers detecting electron and muon neutrino events at Far and Near
positions, 1600 m and 300 m from the proton target, respectively. The ICARUS
T600 detector, the largest LAr-TPC ever built with a size of about 600 ton of
imaging mass, now running in the LNGS underground laboratory, will be moved at
the CERN Far position. An additional 1/4 of the T600 detector (T150) will be
constructed and located in the Near position. Two large area spectrometers will
be placed downstream of the two LAr-TPC detectors to perform charge
identification and muon momentum measurements from sub-GeV to several GeV
energy range, greatly complementing the physics capabilities. This experiment
will offer remarkable discovery potentialities, collecting a very large number
of unbiased events both in the neutrino and antineutrino channels, largely
adequate to definitely settle the origin of the observed neutrino-related
anomalies.Comment: Contribution to the European Strategy for Particle Physics - Open
Symposium Preparatory Group, Kracow 10-12 September 201
Design and implementation of the new scintillation light detection system of ICARUS T600
ICARUS T600 is the far detector of the Short Baseline Neutrino program at
Fermilab(USA), which foresees three Liquid Argon Time Projection Chambers along
the Booster Neutrino Beam line to search for LSND-like sterile neutrino signal.
The T600 detector underwent a significant overhauling process at CERN,
introducing new technological developments while maintaining the already
achieved performances. The realization of a new liquid argon scintillation
light detection system is a primary task of the detector overhaul. As the
detector will be subject to a huge flux of cosmic rays, the light detection
system should allow the 3D reconstruction of events contributing to the
identification of neutrino interactions in the beam spill gate. The design and
implementationof the new scintillation light detection system of ICARUS T600 is
described
Pion yield from 450 GeV/c protons on beryllium
This paper reports on the charged pion production yields measured by the SPY/NA56 experiment for 450 GeV/c proton interactions on beryllium targets. The present data cover a secondary momentum range from 7 GeV/c to 135 GeV/c in the forward direction. An experimental accuracy ranging from 5 to 10\%, depending on the beam momentum, has been achieved, limited mainly by the knowledge of the beam acceptance. These results will be relevant in the calculation of neutrino fluxes in present and future neutrino beams
Topical Review on "Beta-beams"
Neutrino physics is traversing an exciting period, after the important
discovery that neutrinos are massive particles, that has implications from
high-energy physics to cosmology. A new method for the production of intense
and pure neutrino beams has been proposed recently: the ``beta-beam''. It
exploits boosted radioactive ions decaying through beta-decay. This novel
concept has been the starting point for a new possible future facility. Its
main goal is to address the crucial issue of the existence of CP violation in
the lepton sector. Here we review the status and the recent developments with
beta-beams. We discuss the original, the medium and high-energy scenarios as
well as mono-chromatic neutrino beams produced through ion electron-capture.
The issue of the degeneracies is mentioned. An overview of low energy
beta-beams is also presented. These beams can be used to perform experiments of
interest for nuclear structure, for the study of fundamental interactions and
for nuclear astrophysics.Comment: Topical Review for Journal of Physics G: Nuclear and Particle
Physics, published version, minor corrections, references adde
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