109,426 research outputs found
Insular Carcinoma of Thyroid Presenting as a Giant Skull Lesion: A Dilemma in Treatment.
Thyroid surgeons are becoming increasingly more aware of a histologically distinct subset of thyroid carcinoma whose classification falls between well-differentiated and anaplastic carcinomas with respect to both cell differentiation and clinical behavior. This subtype of tumors has been categorized as poorly differentiated or insular carcinoma, based on its characteristic cell groupings. Although the differentiation of insular carcinoma from other thyroid carcinomas has important prognostic and therapeutic significance, relatively little about insular carcinoma has been published in the otolaryngology literature. In this article, we discuss a case of insular carcinoma of thyroid presenting with concurrent distant metastasis to skull, lung, ribs, and inguinal region with review of the literature. We conclude that insular thyroid carcinoma warrants aggressive management with total thyroidectomy and excision of accessible giant lesion followed by radioactive iodine ablation of any remaining thyroid tissue
Deformation and break-up of viscoelastic droplets in confined shear flow
The deformation and break-up of Newtonian/viscoelastic droplets are studied
in confined shear flow. Our numerical approach is based on a combination of
Lattice-Boltzmann models (LBM) and finite difference schemes, the former used
to model two immiscible fluids with variable viscous ratio, and the latter used
to model the polymer dynamics. The kinetics of the polymers is introduced using
constitutive equations for viscoelastic fluids with finitely extensible
non-linear elastic dumbbells with Peterlin's closure (FENE-P). We quantify the
droplet response by changing the polymer relaxation time , the maximum
extensibility of the polymers, and the degree of confinement, i.e. the
ratio of the droplet diameter to gap spacing. In unconfined shear flow, the
effects of droplet viscoelasticity on the critical Capillary number
\mbox{Ca}_{\mbox{\tiny{cr}}} for break-up are moderate in all cases studied.
However, in confined conditions a different behaviour is observed: the critical
Capillary number of a viscoelastic droplet increases or decreases, depending on
the maximum elongation of the polymers, the latter affecting the extensional
viscosity of the polymeric solution. Force balance is monitored in the
numerical simulations to validate the physical picture.Comment: 34 Pages, 13 Figures. This Work applies the Numerical Methodology
described in arXiv:1406.2686 to the Problem of Droplet Break-up in confined
microchannel
Masses and Strong Decay properties of Radially Excited Bottom states B(2S)and B(2P) with their Strange Partners Bs(2S) and Bs(2P)
In this paper, we analyzed the experimentally available radially excited
charm mesons to predict the similar spectra for the n=2 bottom mesons. In the
heavy quark effective theory, we explore the flavor independent parameters to
calculate the masses for the experimentally unknown n=2 bottom mesons B(2S),
B(2P), Bs(2S) and Bs(2P). We have also analyzed these bottom masses by applying
the QCD and 1/mQ corrections to the lagrangian leading to the modification of
flavor symmetry parameters as. Further strong decay widths are determined using
these calculated masses to check the sensitivity of these corrections for these
radially excited mesons. The calculated decay widths are in the form of strong
coupling constant geHH, egSH and egTH. We concluded that these corrections are
less sensitive for n=2 masses as compared to n=1 masses. Branching ratios and
branching fractions of these states are calculated to have a deeper
understanding of these states. These predicted values can be confronted with
the future experimental data.Comment: 11 Pages, 6 Table
Hybrid Lattice Boltzmann/Finite Difference simulations of viscoelastic multicomponent flows in confined geometries
We propose numerical simulations of viscoelastic fluids based on a hybrid
algorithm combining Lattice-Boltzmann models (LBM) and Finite Differences (FD)
schemes, the former used to model the macroscopic hydrodynamic equations, and
the latter used to model the polymer dynamics. The kinetics of the polymers is
introduced using constitutive equations for viscoelastic fluids with finitely
extensible non-linear elastic dumbbells with Peterlin's closure (FENE-P). The
numerical model is first benchmarked by characterizing the rheological
behaviour of dilute homogeneous solutions in various configurations, including
steady shear, elongational flows, transient shear and oscillatory flows. As an
upgrade of complexity, we study the model in presence of non-ideal
multicomponent interfaces, where immiscibility is introduced in the LBM
description using the "Shan-Chen" model. The problem of a confined viscoelastic
(Newtonian) droplet in a Newtonian (viscoelastic) matrix under simple shear is
investigated and numerical results are compared with the predictions of various
theoretical models. The proposed numerical simulations explore problems where
the capabilities of LBM were never quantified before.Comment: 32 Pages, 11 Figure
Fe and N self-diffusion in non-magnetic Fe:N
Fe and N self-diffusion in non-magnetic FeN has been studied using neutron
reflectivity. The isotope labelled multilayers, FeN/57Fe:N and Fe:N/Fe:15N were
prepared using magnetron sputtering. It was remarkable to observe that N
diffusion was slower compared to Fe while the atomic size of Fe is larger
compared to N. An attempt has been made to understand the diffusion of Fe and N
in non-magnetic Fe:N
Full QCD with the L\"uscher local bosonic action
We investigate L\"uscher's method of including dynamical Wilson fermions in a
lattice simulation of QCD with two quark flavours. We measure the accuracy of
the approximation by comparing it with Hybrid Monte Carlo results for gauge
plaquette and Wilson loops. We also introduce an additional global Metropolis
step in the update. We show that the complexity of L\"uscher's algorithm
compares favourably with that of the Hybrid Monte Carlo.Comment: 21 pages Late
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