Utilisation du grand épiploon dans la chirurgie reconstructrice du cancer du sein localement avancé ou récidivant.

Problématique : En Suisse, près de 5300 nouveaux cas de cancer du sein chez la femme et 30 à 40 chez l'homme sont diagnostiqués chaque année. Une femme sur huit sera touchée par la maladie au cours de sa vie (1-2). Malgré l'avancée de la médecine dans le traitement de cette maladie, il arrive encore que des situations dramatiques se présentent suite à une tumeur localement avancée ou récidivante. Une plaie chronique douloureuse et nécrotique parfois surinfectée ne répondant pas aux traitements de chimio- et de radiothérapie nécessite alors d'effectuer une résection large de la zone atteinte afin d'améliorer la qualité de vie de ces patients. Cette opération entraîne un vaste défect de la paroi thoracique antérieure qui demande une chirurgie de couverture complexe. Le lambeau épiploïque proposé par Kiricuta en 1963 est encore utilisé de nos jours pour ce genre d'intervention (3). L'évolution des techniques chirurgicales fait que nous disposons actuellement d'autres lambeaux myocutanés performants pour de telles situations oncologiques. Ce travail s'intéresse à l'évaluation de l'épiplooplastie proposée il y a maintenant près de 50 ans, afin de s'interroger sur la place qu'elle occupe aujourd'hui parmi ces autres techniques. Objectifs : Comprendre la technique du lambeau de Kiricuta et évaluer sa place parmi les techniques de reconstruction dans la chirurgie du cancer du sein localement avancé ou récidivant. Méthodes : Une revue de la littérature des articles s'intéressant au lambeau de Kiricuta depuis 1963 a permis d'évaluer ses qualités et ses inconvénients. Cette technique a été illustrée par l'analyse rétrospective des dossiers de 4 patients ayant bénéficié d'une reconstruction à partir du grand épiploon au CHUV suite à un cancer du sein récidivant ou localement avancé. La présentation des autres techniques de reconstructions de la paroi thoracique antérieure s'est également basée sur la récolte d'articles d'études comparant ces différentes opérations. Résultats: Le grand épiploon est un organe doté de capacités étonnantes, immunologiques et angiogéniques. Sa taille souvent généreuse convient à de grands défects de la paroi thoracique, particulièrement lors d'atteinte bilatérale ou de la région axillaire. Son utilisation ne convient toutefois pas lors d'exérèse de plus de 3 côtes par manque de stabilité de la cage thoracique. Apprécié en milieu infecté et/ou radique, il convient aux situations où les lambeaux myocutanés sont inadéquats. En effet, comme sa taille n'est pas prédictible et que l'opération demande souvent une laparotomie, cette technique est envisagée en seconde intention ou suivant des situations particulières. Conclusion : L'amélioration des symptômes locaux lors de cancer du sein localement avancé ou récidivant a pu être obtenue en excisant la lésion et en la recouvrant par le lambeau de Kiricuta. Le bénéfice sur la qualité de vie ainsi apporté à ces patients fait de l'épiplooplastie un choix à considérer dans le traitement chirurgical du cancer du sein

Temporal relation between quiet-Sun transverse fields and the strong flows detected by IMaX/SUNRISE

Localized strongly Doppler-shifted Stokes V signals were detected by IMaX/SUNRISE. These signals are related to newly emerged magnetic loops that are observed as linear polarization features. We aim to set constraints on the physical nature and causes of these highly Doppler-shifted signals. In particular, the temporal relation between the appearance of transverse fields and the strong Doppler shifts is analyzed in some detail. We calculated the time difference between the appearance of the strong flows and the linear polarization. We also obtained the distances from the center of various features to the nearest neutral lines and whether they overlap or not. These distances were compared with those obtained from randomly distributed points on observed magnetograms. Various cases of strong flows are described in some detail. The linear polarization signals precede the appearance of the strong flows by on average 84+-11 seconds. The strongly Doppler-shifted signals are closer (0.19") to magnetic neutral lines than randomly distributed points (0.5"). Eighty percent of the strongly Doppler-shifted signals are close to a neutral line that is located between the emerging field and pre-existing fields. That the remaining 20% do not show a close-by pre-existing field could be explained by a lack of sensitivity or an unfavorable geometry of the pre-existing field, for instance, a canopy-like structure. Transverse fields occurred before the observation of the strong Doppler shifts. The process is most naturally explained as the emergence of a granular-scale loop that first gives rise to the linear polarization signals, interacts with pre-existing fields (generating new neutral line configurations), and produces the observed strong flows. This explanation is indicative of frequent small-scale reconnection events in the quiet Sun.Comment: 11 pages, 8 figure

A note on the Landauer principle in quantum statistical mechanics

The Landauer principle asserts that the energy cost of erasure of one bit of information by the action of a thermal reservoir in equilibrium at temperature T is never less than $kTlog 2$. We discuss Landauer's principle for quantum statistical models describing a finite level quantum system S coupled to an infinitely extended thermal reservoir R. Using Araki's perturbation theory of KMS states and the Avron-Elgart adiabatic theorem we prove, under a natural ergodicity assumption on the joint system S+R, that Landauer's bound saturates for adiabatically switched interactions. The recent work of Reeb and Wolf on the subject is discussed and compared

Properties of sunspots in cycle 23: I. Dependence of brightness on sunspot size and cycle phase

In this paper we investigate the dependence of umbral core brightness, as well as the mean umbral and penumbral brightness on the phase of the solar cycle and on the size of the sunspot. Albregtsen & Maltby (1978) reported an increase in umbral core brightness from the early to the late phase of solar cycle from the analysis of 13 sunspots which cover solar cycles 20 and 21. Here we revisit this topic by analysing continuum images of more than 160 sunspots observed by the MDI instrument on board the SOHO spacecraft for the period between 1998 March to 2004 March, i.e. a sizable part of solar cycle 23. The advantage of this data set is its homogeneity, with no seeing fluctuations. A careful stray light correction, which is validated using the Mercury transit of 7th May, 2003, is carried out before the umbral and penumbral intensities are determined. The influence of the Zeeman splitting of the nearby NiI spectral line on the measured 'continuum' intensity is also taken into account. We did not observe any significant variation in umbral core, mean umbral and mean penumbral intensities with solar cycle, which is in contrast to earlier findings for the umbral core intensity. We do find a strong and clear dependence of the umbral brightness on sunspot size, however. The penumbral brightness also displays a weak dependence. The brightness-radius relationship has numerous implications, some of which, such as those for the energy transport in umbrae, are pointed out.Comment: 16 pages, 21 postscript figures, accepted for publication in A&

Structure of even-even nuclei using a mapped collective Hamiltonian and the D1S Gogny interaction

A systematic study of low energy nuclear structure at normal deformation is carried out using the Hartree-Fock-Bogoliubov theory extended by the Generator Coordinate Method and mapped onto a 5-dimensional collective quadrupole Hamiltonian. Results obtained with the Gogny D1S interaction are presented from dripline to dripline for even-even nuclei with proton numbers Z=10 to Z=110 and neutron numbers N less than 200. The properties calculated for the ground states are their charge radii, 2-particle separation energies, correlation energies, and the intrinsic quadrupole shape parameters. For the excited spectroscopy, the observables calculated are the excitation energies and quadrupole as well as monopole transition matrix elements. We examine in this work the yrast levels up to J=6, the lowest excited 0^+ states, and the two next yrare 2^+ states. The theory is applicable to more than 90% of the nuclei which have tabulated measurements. The data set of the calculated properties of 1712 even-even nuclei, including spectroscopic properties for 1693 of them, are provided in CEA website and EPAPS repository with this article \cite{epaps}.Comment: 51 pages with 26 Figures and 4 internal tables; this version is accepted by Physical Review

Comparison of solar photospheric bright points between SUNRISE observations and MHD simulations

Bright points (BPs) in the solar photosphere are radiative signatures of magnetic elements described by slender flux tubes located in the darker intergranular lanes. They contribute to the ultraviolet (UV) flux variations over the solar cycle and hence may influence the Earth's climate. Here we combine high-resolution UV and spectro-polarimetric observations of BPs by the SUNRISE observatory with 3D radiation MHD simulations. Full spectral line syntheses are performed with the MHD data and a careful degradation is applied to take into account all relevant instrumental effects of the observations. It is demonstrated that the MHD simulations reproduce the measured distributions of intensity at multiple wavelengths, line-of-sight velocity, spectral line width, and polarization degree rather well. Furthermore, the properties of observed BPs are compared with synthetic ones. These match also relatively well, except that the observations display a tail of large and strongly polarized BPs not found in the simulations. The higher spatial resolution of the simulations has a significant effect, leading to smaller and more numerous BPs. The observation that most BPs are weakly polarized is explained mainly by the spatial degradation, the stray light contamination, and the temperature sensitivity of the Fe I line at 5250.2 \AA{}. The Stokes $V$ asymmetries of the BPs increase with the distance to their center in both observations and simulations, consistent with the classical picture of a production of the asymmetry in the canopy. This is the first time that this has been found also in the internetwork. Almost vertical kilo-Gauss fields are found for 98 % of the synthetic BPs. At the continuum formation height, the simulated BPs are on average 190 K hotter than the mean quiet Sun, their mean BP field strength is 1750 G, supporting the flux-tube paradigm to describe BPs.Comment: Accepted for publication in Astronomy & Astrophysics on May 30 201

Full counting statistics and phase diagram of a dissipative Rydberg gas

Ultra-cold gases excited to strongly interacting Rydberg states are a promising system for quantum simulations of many-body systems. For off-resonant excitation of such systems in the dissipative regime, highly correlated many-body states exhibiting, among other characteristics, intermittency and multi-modal counting distributions are expected to be created. So far, experiments with Rydberg atoms have been carried out in the resonant, non-dissipative regime. Here we realize a dissipative gas of rubidium Rydberg atoms and measure its full counting statistics for both resonant and off-resonant excitation. We find strongly bimodal counting distributions in the off-resonant regime that are compatible with intermittency due to the coexistence of dynamical phases. Moreover, we measure the phase diagram of the system and find good agreement with recent theoretical predictions. Our results pave the way towards detailed studies of many-body effects in Rydberg gases.Comment: 12 pages, 5 figure

Dynamics of multi-cored magnetic structures in the quiet Sun

We report on the dynamical interaction of quiet-Sun magnetic fields and granular convection in the solar photosphere as seen by \textsc{Sunrise}. We use high spatial resolution (0\farcs 15--0\farcs 18) and temporal cadence (33 s) spectropolarimetric Imaging Magnetograph eXperiment data, together with simultaneous CN and Ca\,\textsc{ii}\,H filtergrams from \textsc{Sunrise} Filter Imager. We apply the SIR inversion code to the polarimetric data in order to infer the line of sight velocity and vector magnetic field in the photosphere. The analysis reveals bundles of individual flux tubes evolving as a single entity during the entire 23 minute data set. The group shares a common canopy in the upper photospheric layers, while the individual tubes continually intensify, fragment and merge in the same way that chains of bright points in photometric observations have been reported to do. The evolution of the tube cores are driven by the local granular convection flows. They intensify when they are "compressed" by surrounding granules and split when they are "squeezed" between two moving granules. The resulting fragments are usually later regrouped in intergranular lanes by the granular flows. The continual intensification, fragmentation and coalescence of flux results in magnetic field oscillations of the global entity. From the observations we conclude that the magnetic field oscillations first reported by \citet{2011ApJ...730L..37M} correspond to the forcing by granular motions and not to characteristic oscillatory modes of thin flux tubes.Comment: 12 pages, 7 figures. Accepted in ApJ. Animation 1 can be downloaded from: http://spg.iaa.es/download

Convective motions and net circular polarization in sunspot penumbrae

We have employed a penumbral model, that includes the Evershed flow and convective motions inside penumbral filaments, to reproduce the azimuthal variation of the net circular polarization (NCP) in sunspot penumbrae at different heliocentric angles for two different spectral lines. The theoretical net circular polarization fits the observations as satisfactorily as penumbral models based on flux-tubes. The reason for this is that the effect of convective motions on the NCP is very small compared to the effect of the Evershed flow. In addition, the NCP generated by convective upflows cancels out the NCP generated by the downflows. We have also found that, in order to fit the observed NCP, the strength of the magnetic field inside penumbral filaments must be very close to 1000 G. In particular, field-free or weak-field filaments fail to reproduce both the correct sign of the net circular polarization, as well as its dependence on the azimuthal and heliocentric angles.Comment: Accepted for publication in the Astrophysical Journal. 10 pages, 7 figures (3 in color). Uses emulatedap