1,063 research outputs found
Risk stratification of cardiac arrhythmias and sudden cardiac death in type 2 diabetes mellitus patients receiving insulin therapy: A population-based cohort study
Introduction
Metabolic abnormalities may exacerbate the risk of adverse outcomes in patients with type 2 diabetes mellitus. The present study aims to assess the predictive value of HbA1c and lipid variability on the risks of sudden cardiac death (SCD) and incident atrial fibrillation (AF).
Methods
The retrospective observational study consists of type 2 diabetic patients prescribed with insulin, who went to publicly funded clinics and hospitals in Hong Kong between January 1, 2009 and December 31, 2009. Variability in total cholesterol, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), triglyceride, and HbA1c were assessed through their SD and coefficient of variation. The primary outcomes were incident (1) ventricular tachycardia/ventricular fibrillation, actual or aborted SCD and (2) AF.
Results
A total of 23 329 patients (mean ± SD age: 64 ± 14 years old; 51% male; mean HbA1c 8.6 ± 1.3%) were included. On multivariable analysis, HbA1c, total cholesterol, LDL-C and triglyceride variability were found to be predictors of SCD (p < .05).
Conclusion
HbA1c and lipid variability were predictive of SCD. Therefore, poor glucose control and variability in lipid parameters in diabetic patients are associated with aborted or actual SCD. These observations suggest the need to re-evaluate the extent of glycemic control required for outcome optimization
Gauge Threshold Corrections in Warped Geometry
We discuss the Kaluza-Klein threshold correction to low energy gauge
couplings in theories with warped extra-dimension, which might be crucial for
the gauge coupling unification when the warping is sizable. Explicit
expressions of one-loop thresholds are derived for generic 5D gauge theory on a
slice of AdS_5, where some of the bulk gauge symmetries are broken by orbifold
boundary conditions and/or by bulk Higgs vacuum values. Effects of the mass
mixing between the bulk fields with different orbifold parities are included as
such mixing is required in some class of realistic warped unification models.Comment: 33 pages, 1 figure, 6 tables, invited contribution to New Journal of
Physics Focus Issue on 'Extra Space Dimensions
Quantum Optomechanics with Single Atom
The recently increasing explorations for cavity optomechanical coupling
assisted by a single atom or an atomic ensemble have opened an experimentally
accessible fashion to interface quantum optics and nano (micro) -mechanical
systems. In this paper, we study in details such composite quantum dynamics of
photon, phonon and atoms, specified by the triple coupling, which only exists
in this triple hybrid system: The cavity QED system with a movable end mirror.
We exactly diagonalize the Hamiltonian of the triple hybrid system under the
parametric resonance condition. We find that, with the rotating-wave
approximation, the hybrid system is modeled by a generalized spin-orbit
coupling where the orbital angular momentum operator is defined through a
Jordan-Schwinger realization with two bosonic modes, corresponding to the
mirror oscillation and the single mode photon of the cavity. In the
quasi-classical limit of very large angular momentum, this system will behave
like a standard cavity-QED system described by the Jaynes-Cummings model as the
angular momentum operators are transformed to bosonic operators of a single
mode. We test this observation with an experimentally accessible system with
the atom in the cavity with a moving mirror.Comment: 9 pages, 8 figure
State sampling dependence of the Hopfield network inference
The fully connected Hopfield network is inferred based on observed
magnetizations and pairwise correlations. We present the system in the glassy
phase with low temperature and high memory load. We find that the inference
error is very sensitive to the form of state sampling. When a single state is
sampled to compute magnetizations and correlations, the inference error is
almost indistinguishable irrespective of the sampled state. However, the error
can be greatly reduced if the data is collected with state transitions. Our
result holds for different disorder samples and accounts for the previously
observed large fluctuations of inference error at low temperatures.Comment: 4 pages, 1 figure, further discussions added and relevant references
adde
Radius-dependent gauge unification in AdS5
We examine the relation of the 4-dimensional low energy coupling of bulk
gauge boson in a slice of AdS5 to the 5-dimensional fundamental couplings as a
function of the orbifold radius R. This allows us to address the gauge coupling
unification in AdS5 by means of the radius running as well as the conventional
momentum running. We then compute the radius dependence of 1-loop low energy
couplings in generic AdS5 theory with 4-dimensional supersymmetry, and discuss
the low energy predictions when the 5-dimensional couplings are assumed to be
unified.Comment: 11 pages, 2 figures, revtex, v3: analysis was generalized to
S^1/Z_2*Z_2 orbifoldin
Andreev scattering and Josephson current in a one-dimensional electron liquid
Andreev scattering and the Josephson current through a one-dimensional
interacting electron liquid sandwiched between two superconductors are
re-examined. We first present some apparently new results on the
non-interacting case by studying an exactly solvable tight-binding model rather
than the usual continuum model. We show that perfect Andreev scattering (i.e.
zero normal scattering) at the Fermi energy can only be achieved by fine-tuning
junction parameters. We also obtain exact results for the Josephson current,
which is generally a smooth function of the superconducting phase difference
except when the junction parameters are adjusted to give perfect Andreev
scattering, in which case it becomes a sawtooth function. We then observe that,
even when interactions are included, all low energy properties of a junction
(E<<\Delta, the superconducting gap) can be obtained by "integrating out" the
superconducting electrons to obtain an effective Hamiltonian describing the
metallic electrons only with a boundary pairing interaction. This boundary
model provides a suitable starting point for bosonization/renormalization
group/boundary conformal field theory analysis. We argue that total normal
reflection and total Andreev reflection correspond to two fixed points of the
boundary renormalization group. For repulsive bulk interactions the Andreev
fixed point is unstable and the normal one stable. However, the reverse is true
for attractive interactions. This implies that a generic junction Hamiltonian
(without fine-tuned junction parameters) will renormalize to the normal fixed
point for repulsive interactions but to the Andreev one for attractive
interactions. An exact mapping of our tight-binding model to the Hubbard model
with a transverse magnetic field is used to help understand this behavior.Comment: revtex, 17 pages, 5 postscript figure
Quantized bulk fermions in the Randall-Sundrum brane model
The lowest order quantum corrections to the effective action arising from
quantized massive fermion fields in the Randall-Sundrum background spacetime
are computed. The boundary conditions and their relation with gauge invariance
are examined in detail. The possibility of Wilson loop symmetry breaking in
brane models is also analysed. The self-consistency requirements, previously
considered in the case of a quantized bulk scalar field, are extended to
include the contribution from massive fermions. It is shown that in this case
it is possible to stabilize the radius of the extra dimensions but it is not
possible to simultaneously solve the hierarchy problem, unless the brane
tensions are dramatically fine tuned, supporting previous claims.Comment: 25 pages, 1 figure, RevTe
Improving the sensitivity of Higgs boson searches in the golden channel
Leptonic decays of the Higgs boson in the ZZ* channel yield what is known as
the golden channel due to its clean signature and good total invariant mass
resolution. In addition, the full kinematic distribution of the decay products
can be reconstructed, which, nonetheless, is not taken into account in
traditional search strategy relying only on measurements of the total invariant
mass. In this work we implement a type of multivariate analysis known as the
matrix element method, which exploits differences in the full production and
decay matrix elements between the Higgs boson and the dominant irreducible
background from q bar{q} -> ZZ*. Analytic expressions of the differential
distributions for both the signal and the background are also presented. We
perform a study for the Large Hadron Collider at sqrt{s}=7 TeV for Higgs masses
between 175 and 350 GeV. We find that, with an integrated luminosity of 2.5
fb^-1 or higher, improvements in the order of 10 - 20 % could be obtained for
both discovery significance and exclusion limits in the high mass region, where
the differences in the angular correlations between signal and background are
most pronounced.Comment: 31 pages, 8 figures. v2: Minus signs in definitions of angles
corrected. Typos fixed. Reference added. Cosmetic changes to Figure 4.
Additional sentence added for clarificatio
Objective response by mRECIST as a predictor and potential surrogate end point of overall survival in advanced HCC
Background & Aims: The Modified Response Evaluation Criteria in Solid Tumors (mRECIST) was developed to overcome the limitations of standard RECIST criteria in response assessment of hepatocellular carcinoma (HCC). We aimed to investigate whether objective response by mRECIST accurately predicted overall survival (OS) in patients with advanced HCC treated with systemic targeted therapies and also to preliminarily assess this endpoint as a potential surrogate of OS.Methods: Individual patient data from the BRISK-PS randomized phase III trial comparing brivanib vs. placebo (the first to prospectively incorporate mRECIST) were used to analyze objective response as a predictor of OS in a time-dependent covariate analysis. Patients with available imaging scans during follow-up were included (n = 334; 85% of those randomized). Moreover, a correlation of the survival probability in deciles vs. the observed objective response was performed to evaluate its suitability as a surrogate end-point.Results: Objective response was observed in 11.5% and 1.9% of patients treated with brivanib and placebo respectively, and was associated with a better survival (median OS 15.0 vs. 9.4 months, p < 0.001). In addition, objective response had an independent prognostic value (HR = 0.48; 95% confidence interval [CI], 0.26-0.91, p = 0.025) along with known prognostic factors. Finally, objective response showed promising results as a surrogate of OS in this trial (R = -0.92; 95% CI, -1 to -0.73, p < 0.001). It was an early indicator of the treatment effect (median time to objective response was 1.4 months).Conclusions: Objective response by mRECIST in advanced HCC predicts OS and thus can be considered as a candidate surrogate end-point. Further studies are needed to support this finding.Lay summary: There is a need to identify surrogate end-points for overall survival in advanced hepatocellular carcinoma. We studied patients from the phase III BRISK trial, comparing brivanib treatment with placebo after sorafenib progression. We demonstrate that objective response is an independent predictor of survival and qualifies as a potential surrogate end-point for overall survival in this patient population.Clinical trial number: NCT00825955
Joint EANM/EANO/RANO/SNMMI practice guideline/procedure standards for diagnostics and therapy (theranostics) of meningiomas using radiolabeled somatostatin receptor ligands:version 1.0
Purpose To provide practice guideline/procedure standards for diagnostics and therapy (theranostics) of meningiomas using radiolabeled somatostatin receptor (SSTR) ligands.Methods This joint practice guideline/procedure standard was collaboratively developed by the European Association of Nuclear Medicine (EANM), the Society of Nuclear Medicine and Molecular Imaging (SNMMI), the European Association of Neurooncology (EANO), and the PET task force of the Response Assessment in Neurooncology Working Group (PET/RANO).Results Positron emission tomography (PET) using somatostatin receptor (SSTR) ligands can detect meningioma tissue with high sensitivity and specificity and may provide clinically relevant information beyond that obtained from structural magnetic resonance imaging (MRI) or computed tomography (CT) imaging alone. SSTR-directed PET imaging can be particularly useful for differential diagnosis, delineation of meningioma extent, detection of osseous involvement, and the differentiation between posttherapeutic scar tissue and tumour recurrence. Moreover, SSTR-peptide receptor radionuclide therapy (PRRT) is an emerging investigational treatment approach for meningioma.Conclusion These practice guidelines will define procedure standards for the application of PET imaging in patients with meningiomas and related SSTR-targeted PRRTs in routine practice and clinical trials and will help to harmonize data acquisition and interpretation across centers, facilitate comparability of studies, and to collect larger databases. The current document provides additional information to the evidence-based recommendations from the PET/RANO Working Group regarding the utilization of PET imaging in meningiomas Galldiks (Neuro Oncol. 2017;19(12):1576-87). The information provided should be considered in the context of local conditions and regulations
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