8,541 research outputs found

    Total thyroidectomy versus hemithyroidectomy for patients with follicular neoplasm. A cost-utility analysis

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    AbstractIntroductionThyroid nodules are a common condition. Overall, 20% of the nodules assessed with FNAB correspond to the follicular pattern. A partial thyroidectomy is the minimal procedure that should be performed to determine the nature of these nodules. Some authors have suggested performing a total thyroidectomy based on the elimination of reoperation and ultrasound follow-up. The aim of this study was to evaluate the most cost-useful surgical strategy in a patient with an undetermined nodule, assessing complications, reoperation, recurrence and costs.Material and methodsA cost-utility study was designed to compare hemithyroidectomy and total thyroidectomy. The outcomes were complications (definitive RLN palsy, permanent hypoparathyroidism, reoperation for cancer, and recurrence of the disease), direct costs and utility. We used the payer perspective at 5 years. A deterministic and probabilistic sensitivity analysis was completed.ResultsIn a deterministic analysis, the cost, utility and cost-utility ratio was COP 12.981.801,44.5andCOP12.981.801, 44.5 and COP 291.310 for total thyroidectomy and COP 14.309.889,42.0and14.309.889, 42.0 and 340.044 for partial thyroidectomy, respectively. The incremental cost-utility ratio was −$535.302 favoring total thyroidectomy. Partial thyroidectomy was more cost-effective when the risks of RLN injury and definitive hypoparathyroidism were greater than 8% and 9% in total thyroidectomy, respectively. In total, 46.8% of the simulations for partial thyroidectomy were located in the quadrant of more costly and less effective.ConclusionUnder a common range of complications, and considering the patient's preference and costs, total thyroidectomy should be selected as the most cost-effective treatment for patients with thyroid nodules and follicular patterns

    Heavy-Light Meson Decay Constant from QCD Sum Rules in Three-Loop Approximation

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    In this paper we compute the decay constant of the pseudo-scalar heavy-light mesons in the heavy quark effective theory framework of QCD sum rules. In our analysis we include the recently evaluated three-loop result of order αs2\alpha_s^2 for the heavy-light current correlator. The value of the bottom quark mass, which essentially limits the accuracy of the sum rules for BB meson, is extracted from the nonrelativistic sum rules for ΄\Upsilon resonances in the next-to-next-to-leading approximation. We find stability of our result with respect to all types of corrections and the specific form of the sum rule which reduces the uncertainty. Our results fB=206±20f_B=206\pm 20 MeV and fD=195±20f_D=195\pm 20 MeV for the BB and DD meson decay constants are in impressive agreement with recent lattice calculations.Comment: minor editorial changes, references added, to appear in PR

    QCD sum rules for the pseudoscalar decay constants - To constrain the strange quark mass

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    We study the higher order corrections of quark masses to the Gell-Mann−-Oakes−-Renner (GOR) relation by constructing QCD sum rules exclusively for pseudoscalar mesons from the axial-vector correlation function, i∫d4x eip⋅xi \int d^4x~ e^{ip\cdot x} . To project out the pseudoscalar meson contributions, we apply −pÎŒpÎœ/p2-p^\mu p^\nu/p^2 to this correlation function and construct sum rules for the decay constants of pseudoscalar mesons, fπ,fkf_\pi, f_k and fη8f_{\eta_8}. The OPE is proportional to quark masses due to PCAC. To leading order in quark mass, each sum rule reproduces the corresponding GOR relation. For kaon and η8\eta_8, the deviation from the GOR relation due to higher orders in quark mass is found to be substantial. But the deviation gives better agreements with the phenomenology. Our sum rule provides a sensitive relation between fKf_K and msm_s, which stringently constrain the value for msm_s. To reproduce the experimental value for fKf_K, msm_s is found to be 186 MeV at 1 GeV scale. The fη8f_{\eta_8} sum rule also supports this finding.Comment: 14 pages including 3 figures. slightly revised. Accepted for publication in Physical Review

    Consistent modified gravity: dark energy, acceleration and the absence of cosmic doomsday

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    We discuss the modified gravity which includes negative and positive powers of the curvature and which provides the gravitational dark energy. It is shown that in GR plus the term containing negative power of the curvature the cosmic speed-up may be achieved, while the effective phantom phase (with ww less than -1) follows when such term contains the fractional positive power of the curvature. The minimal coupling with matter makes the situation more interesting: even 1/R theory coupled with the usual ideal fliud may describe the (effective phantom) dark energy. The account of R2R^2 term (consistent modified gravity) may help to escape of cosmic doomsday.Comment: LaTeX file, 9 pages, based on the talk given by S.D. Odintsov (Int. Conference Mathematical Methods in Physics, Rio de Janeiro, Augest, 2004), to appear in CQG, Letter

    Management and 1-year outcomes of patients with newly diagnosed atrial fibrillation and chronic kidney disease: Results from the prospective garfield-af registry

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    © 2019 The Authors. Background-—Using data from the GARFIELD-AF (Global Anticoagulant Registry in the FIELD–Atrial Fibrillation), we evaluated the impact of chronic kidney disease (CKD) stage on clinical outcomes in patients with newly diagnosed atrial fibrillation (AF). Methods and Results-—GARFIELD-AF is a prospective registry of patients from 35 countries, including patients from Asia (China, India, Japan, Singapore, South Korea, and Thailand). Consecutive patients enrolled (2013–2016) were classified with no, mild, or moderate-to-severe CKD, based on the National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative guidelines. Data on CKD status and outcomes were available for 33 024 of 34 854 patients (including 9491 patients from Asia); 10.9% (n=3613) had moderate-to-severe CKD, 16.9% (n=5595) mild CKD, and 72.1% (n=23 816) no CKD. The use of oral anticoagulants was influenced by stroke risk (ie, post hoc assessment of CHA2DS2-VASc score), but not by CKD stage. The quality of anticoagulant control with vitamin K antagonists did not differ with CKD stage. After adjusting for baseline characteristics and antithrombotic use, both mild and moderate-to-severe CKD were independent risk factors for all-cause mortality. Moderate-to-severe CKD was independently associated with a higher risk of stroke/systemic embolism, major bleeding, new-onset acute coronary syndrome, and new or worsening heart failure. The impact of moderate-to-severe CKD on mortality was significantly greater in patients from Asia than the rest of the world (P=0.001). Conclusions-—In GARFIELD-AF, moderate-to-severe CKD was independently associated with stroke/systemic embolism, major bleeding, and mortality. The effect of moderate-to-severe CKD on mortality was even greater in patients from Asia than the rest of the world

    Microsatellite alterations and TP53 mutations in plasma DNA of small-cell lung cancer patients: Follow-up study and prognostic significance

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    Background: Small-cell lung cancer (SCLC), one of the major types of lung cancer, is associated with many different somatic molecular genetic changes. These alterations, observed in tumor DNA, have also been identified in the plasma DNA of patients. We undertook the present study to make a prospective investigation into the correlation between abnormal plasma DNA and patient survival. Patients and methods: Thirty-five patients with SCLC were selected after histological diagnosis. Polymorphic markers (ACTBP2, UT762 and AR) were chosen for their reported high rate of alterations in SCLC and analyzed in tumor tissue, normal blood cells and plasma DNA. Furthermore, we looked for mutations of the TP53 gene in tumor and plasma DNA. Results: In 25 patients (71%) at least one molecular change precisely matching that of the primary tumor was detected in the plasma DNA. No difference in survival was observed between patients with aberrant plasma DNA and patients without plasma DNA alterations. However, patients with microsatellite modifications and TP53 mutations concomitantly, showed a significant difference (P = 0.02) in survival compared with patients bearing only one of these molecular changes. In 15 cases it was possible to find a correlation either between tumor response and disappearance of abnormal plasma DNA, or tumor progression and persistence of plasma DNA alterations. Conclusions: Free plasma DNA with molecular alterations is present to a high degree in plasma DNA of SCLC patients and may have a role as a prognostic facto

    Numerical study of the strongly screened vortex glass model in an external field

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    The vortex glass model for a disordered high-T_c superconductor in an external magnetic field is studied in the strong screening limit. With exact ground state (i.e. T=0) calculations we show that 1) the ground state of the vortex configuration varies drastically with infinitesimal variations of the strength of the external field, 2) the minimum energy of global excitation loops of length scale L do not depend on the strength of the external field, however 3) the excitation loops themself depend sensibly on the field. From 2) we infer the absence of a true superconducting state at any finite temperature independent of the external field.Comment: 6 pages RevTeX, 5 eps-figures include

    Covariant and Heavy Quark Symmetric Quark Models

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    There exist relativistic quark models (potential or MIT-bag) which satisfy the heavy quark symmetry (HQS) relations among meson decay constants and form factors. Covariant construction of the momentum eigenstates, developed here, can correct for spurious center-of-mass motion contributions.Proton form factor and M1 transitions in quarkonia are calculated. Explicit expression for the Isgur-Wise function is found and model determined deviations from HQS are studied. All results depend on the model parameters only. No additional ad hoc assumptions are needed.Comment: 34 pages (2 figures not included but avaliable upon request), LATEX, (to be published in Phys.Rev.D

    Jet Quenching in Heavy Ion Collisions

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    This review article was prepared for the Landolt-Boernstein volume on Relativisitc Heavy Ion Physics.Comment: Review articel accepted for publication in the Landolt-Boernstein Handbook of Physics, ed. R. Stock. 41 pages LaTex, 7 eps-figure
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