123 research outputs found
Eta-mesic nuclei
In this contribution we report on theoretical studies of nuclear
quasi-bound states in few- and many-body systems performed recently by the
Jerusalem-Prague Collaboration [1-5]. Underlying energy-dependent
interactions are derived from coupled-channel models that incorporate the
resonance. The role of self-consistent treatment of the strong
energy dependence of subthreshold amplitudes is discussed. Quite large
downward energy shift together with rapid decrease of the amplitudes
below threshold result in relatively small binding energies and widths of the
calculated nuclear bound states. We argue that the subthreshold behavior
of scattering amplitudes is crucial to conclude whether nuclear
states exist, in which nuclei the meson could be bound and if the
corresponding widths are small enough to allow detection of these
nuclear states in experiment.Comment: 7 pages, 5 figures; presented at HADRON2017, Sept. 25-29, 2017,
Salamanca (Spain); prepared for Proceedings of Scienc
Mechanisms that link the oncogenic epithelial–mesenchymal transition to suppression of anoikis
The oncogenic epithelial–mesenchymal transition (EMT) contributes to tumor progression in various context-dependent ways, including increased metastatic potential, expansion of cancer stem cell subpopulations, chemo-resistance and disease recurrence. One of the hallmarks of EMT is resistance of tumor cells to anoikis. This resistance contributes to metastasis and is a defining property not only of EMT but also of cancer stem cells. Here, we review the mechanistic coupling between EMT and resistance to anoikis. The discussion focuses on several key aspects. First, we provide an update on new pathways that lead from the loss of E-cadherin to anoikis resistance. We then discuss the relevance of transcription factors that are crucial in wound healing in the context of oncogenic EMT. Next, we explore the consequences of the breakdown of cell-polarity complexes upon anoikis sensitivity, through the Hippo, Wnt and transforming growth factor β (TGF-β) pathways, emphasizing points of crossregulation. Finally, we summarize the direct regulation of cell survival genes through EMT-inducing transcription factors, and the roles of the tyrosine kinases focal adhesion kinase (FAK) and TrkB neurotrophin receptor in EMT-related regulation of anoikis. Emerging from these studies are unifying principles that will lead to improvements in cancer therapy by reprogramming sensitivity of anoikis
Latest results for the antikaon-nucleon optical potential
The key question of this letter is whether the K-nucleus optical potential is
deep, as it is prefered by the phenomenological fits to kaonic atoms data, or
shallow, as it comes out from unitary chiral model calculations. The current
experimental situation is reviewed.Comment: 3 pages, 1 figure. Presented at the 21st European Conference on the
Few-Body problems in Physics (EFB21), Salamanca, Spain, August 29 - September
3, 201
Antikaons and hyperons in nuclear matter with saturation
We evaluate the antikaon and hyperon spectral functions in a self-consistent
and covariant many-body approach. The computation is based on coupled-channel
dynamics derived from the chiral SU(3) Lagrangian. A novel subtraction scheme
is developed that avoids kinematical singularities and medium-induced power
divergencies all together. Scalar and vector mean fields are used to model
nuclear binding and saturation. The effect of the latter is striking for the
antikaon spectral function that becomes significantly more narrow at small
momenta. Attractive mass shifts of about 30 and 40 MeV are predicted for the
Lambda(1405) and Sigma(1385) resonances. Once scalar and vector mean fields for
the nucleon are switched on the Lambda(1520) resonances dissolves almost
completely in nuclear matter. All together only moderate attraction is
predicted for the nuclear antikaon systems at saturation density. However, at
larger densities we predict a sizable population of soft antikaon modes that
arise from the coupling of the antikaon to a highly collective Lambda(1115)
nucleon-hole state. This may lead to the formation of exotic nuclear systems
with strangeness and antikaon condensation in compact stars at moderate
densities.Comment: 49 pages, 13 figures, The revised manuscript contains additional
material at twice nuclear saturation density. An unexpected and novel
mechanism is unravelled that may have dramatic implications on the formation
of exotic nuclear systems with strangeness and antikaon condensation in
compact star
Renal oncocytoma: a comparative clinicopathologic study and fluorescent in-situ hybridization analysis of 73 cases with long-term follow-up
Clinical studies have confirmed that renal oncocytoma (RO) is a benign neoplasm with excellent prognosis. In diagnostically challenging cases of renal oncocytic epithelial neoplasms, fluorescent in-situ hybridization (FISH) is increasingly being used and its ability to distinguish RO from chromophobe renal cell carcinoma (ChRCC) has been documented. In this study, we evaluated the differential diagnostic contribution of FISH in cases of RO
Elastic Pion Scattering on the Deuteron in a Multiple Scattering Model
Pion elastic scattering on deuterium is studied in the KMT multiple
scattering approach developed in momentum space. Using a Paris wave function
and the same methods and approximations as commonly used in pion scattering on
heavier nuclei excellent agreement with differential cross section data is
obtained for a wide range of pion energies. Only for MeV and very
backward angles, discrepancies appear that are reminiscent of disagreements in
pion scattering on He, H, and He. At low energies the second order
corrections have been included. Polarization observables are studied in detail.
While tensor analyzing powers are well reproduced, vector analyzing powers
exhibit dramatic discrepancies.Comment: 25 pages LATEX and 9 postscript figures in a self-extracting uufile
archiv
Separable potential model for interactions at low energies
The effective separable meson-baryon potentials are constructed to match the
equivalent chiral amplitudes up to the second order in external meson momenta.
We fit the model parameters (low energy constants) to the threshold and low
energy data. In the process, the -proton bound state problem is
solved exactly in the momentum space and the 1s level characteristics of the
kaonic hydrogen are computed simultaneously with the available low energy
cross sections. The model is also used to describe the
mass spectrum and the energy dependence of the amplitude.Comment: 31 pages, v2 - added corrections to make it compatible with the
published versio
Pion interaction with the trinucleon up to the eta production threshold
Pion elastic, charge exchange scattering and induced eta production on the
trinucleon systems are investigated in a coupled-channels approach in momentum
space with Fadeev wave functions. The channel is
included using an isobar model with S-, P-, and D-wave resonances. While the
coherent reactions like He(He can be reasonably well reproduced
up to =500 MeV, large discrepancies appear for the incoherent
processes, He(H and He(H at backward
angles and energies above -resonance. In the forward direction the
calculations underestimate the experimental measurements very
close to threshold but agreement with the data improves with increasing pion
energy. Predictions are made for the asymmetries of the various reactions on
polarized He.Comment: 40 pages, 12 figures (available from the authors), Mainz preprint
MKPH-T-92-1
The reaction on p-shell nuclei
This letter is concerned with the study of the reaction in p-shell nuclei, i.e., , ,
and . The emission rates are
reported as a function of . These rates are discussed in comparison with
previous findings. The ratio in p-shell nuclei is
found to depart largely from that on hydrogen, which provides support for large
in-medium effects possibly generated by the sub-threshold . The
continuum momentum spectra of prompt pions and free sigmas are also discussed
as well as the missing mass behavior and the link with the
reaction mechanism. The apparatus used for the investigation is the FINUDA
spectrometer operating at the DANE -factory (LNF-INFN, Italy).Comment: 14 pages, 5 figures, accepted for publication in Phys. Lett.
Correlated pairs from the reaction
Correlated pairs emitted after the absorption of negative kaons
at rest in light nuclei and are
studied. -hyperons and deuterons are found to be preferentially
emitted in opposite directions. The invariant mass spectrum of
shows a bump whose mass is 32516 MeV/c. The bump mass (binding
energy), width and yield are reported. The appearance of a bump is discussed in
the realm of the [] clustering process in nuclei. The experiment was
performed with the FINUDA spectrometer at DANE (LNF).Comment: 13 pages, 5 figures, accepted for publication in Phys. Lett.
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