Il trattamento chirurgico dei tumori maligni del labbro. Esperienza personale

I tumori maligni del labbro rappresentano circa l’1-2% delle neoplasie cervico-facciali. Tali lesioni sono più frequentemente costi - tuite da carcinomi spinocellulari e basocellulari che nel complesso rappresentano il 25% di tutti i tumori orali. Mentre il carcinoma spinocellulare si localizza soprattutto sul labbro inferiore, il carcino - ma basocellulare si riscontra maggiormente sul labbro superiore .Il sesso maschile risulta essere sensibilmente il più colpito. L’etiopatoge - nesi di queste neoplasie è legata all’esposizione solare, al fumo, alla predisposizione genetica (mutazione del gene soppressore p53), all’e - voluzione di forme di precancerosi, quali radiodermiti, cheiliti croni - che, xeroderma pigmentosum. Inoltre, alcuni Autori enfatizzano il ruolo svolto da diversi agenti virali quali HPV16, HPV24, HSV1 e HSV2. Il trattamento dei carcinomi del labbro è prevalentemente chirurgico ed è fondamentalmente rappresentato dall’escissione della lesione e successiva ricostruzione del labbro. Le tecniche riparative sono numerose e per la maggior parte basate sull’utilizzo di lembi cutanei locali di scorrimento e di rotazione. La ricostruzione del lab - bro comporta un notevole impegno al fine di preservare quanto più possibile forma e funzioni essendo il labbro fondamentale nell’ali - mentazione, nella fonazione e nella mimica espressiva. Gli Autori riportano la loro esperienza riguardo il trattamento chi - rurgico di 19 pazienti, 17 di sesso maschile, di età compresa tra 58 e 84 anni (età media 72 anni), affetti da carcinoma del labbro (16 spi - nocellulari, 3 basocellulari) con prevalenza di forme ben differenziate. Vengono inoltre discusse le principali problematiche ricostruttive ine - renti la preservazione degli aspetti estetici e funzionali delle labbra

Technical note: Rapid image-based field methods improve the quantification of termite mound structures and greenhouse-gas fluxes

Termite mounds (TMs) mediate biogeochemical processes with global relevance, such as turnover of the important greenhouse gas methane (CH4). However, the complex internal and external morphology of TMs impede an accurate quantitative description. Here we present two novel field methods, photogrammetry (PG) and cross-sectional image analysis, to quantify TM external and internal mound structure of 29 TMs of three termite species. Photogrammetry was used to measure epigeal volume (VE), surface area (AE) and mound basal area (AB) by reconstructing 3-D models from digital photographs, and compared against a water-displacement method and the conventional approach of approximating TMs by simple geometric shapes. To describe TM internal structure, we introduce TM macro- and micro-porosity (θM and θμ), the volume fractions of macroscopic chambers, and microscopic pores in the wall material, respectively. Macro-porosity was estimated using image analysis of single TM cross sections, and compared against full X-ray computer tomography (CT) scans of 17 TMs. For these TMs we present complete pore fractions to assess species-specific differences in internal structure. The PG method yielded VE nearly identical to a water-displacement method, while approximation of TMs by simple geometric shapes led to errors of 4–200 %. Likewise, using PG substantially improved the accuracy of CH4 emission estimates by 10–50 %. Comprehensive CT scanning revealed that investigated TMs have species-specific ranges of θM and θμ, but similar total porosity. Image analysis of single TM cross sections produced good estimates of θM for species with thick walls and evenly distributed chambers. The new image-based methods allow rapid and accurate quantitative characterisation of TMs to answer ecological, physiological and biogeochemical questions. The PG method should be applied when measuring greenhouse-gas emissions from TMs to avoid large errors from inadequate shape approximations

Single-hit resolution measurement with MEG II drift chamber prototypes

Drift chambers operated with helium-based gas mixtures represent a common solution for tracking charged particles keeping the material budget in the sensitive volume to a minimum. The drawback of this solution is the worsening of the spatial resolution due to primary ionisation fluctuations, which is a limiting factor for high granularity drift chambers like the MEG II tracker. We report on the measurements performed on three different prototypes of the MEG II drift chamber aimed at determining the achievable single-hit resolution. The prototypes were operated with helium/isobutane gas mixtures and exposed to cosmic rays, electron beams and radioactive sources. Direct measurements of the single hit resolution performed with an external tracker returned a value of 110 $\mu$m, consistent with the values obtained with indirect measurements performed with the other prototypes.Comment: 18 pages, 18 figure

Measurement of the radiative decay of polarized muons in the MEG experiment

We studied the radiative muon decay $\mu^+ \to e^+\nu\bar{\nu}\gamma$ by using for the first time an almost fully polarized muon source. We identified a large sample (~13000) of these decays in a total sample of 1.8x10^14 positive muon decays collected in the MEG experiment in the years 2009--2010 and measured the branching ratio B($\mu^+ \to e^+\nu\bar{\nu}\gamma$) = (6.03+-0.14(stat.)+-0.53(sys.))x10^-8 for E_e > 45 MeV and E_{\gamma} > 40 MeV, consistent with the Standard Model prediction. The precise measurement of this decay mode provides a basic tool for the timing calibration, a normalization channel, and a strong quality check of the complete MEG experiment in the search for $\mu^+ \to e^+\gamma$ process.Comment: 8 pages, 7 figures. Added an introduction to NLO calculation which was recently calculated. Published versio

Gas Distribution and Monitoring for the Drift Chamber of the MEG-II Experiment

The reconstruction of the positron trajectory in the MEG-II experiment searching for the $\mu^+ \to e^+ \gamma$ decay uses a cylindrical drift chamber operated with a helium-isobutane gas mixture. A stable performance of the detector in terms of its electron drift properties, avalanche multiplication, and with a gas mixture of controlled composition and purity has to be provided and continuously monitored. In this paper we describe the strategies adopted to meet the requirements imposed by the target sensitivity of MEG-II, including the construction and commissioning of a small chamber for an online monitoring of the gas quality.Comment: 12 pages, 6 figures, submitted to Journal of Instrumentatio

The measuring systems of the wire tension for the MEG II Drift Chamber by means of the resonant frequency technique

The ultra-low mass Cylindrical Drift Chamber designed for the MEG experiment upgrade is a challenging apparatus made of 1728 phi = 20 micron gold plated tungsten sense wires, 7680 phi = 40 micron and 2496 phi = 50 micron silver plated aluminum field wires. Because of electrostatic stability requirements all the wires have to be stretched at mechanical tensions of about 25, 19 and 29 g respectively which must be controlled at a level better than 0.5 g. This chamber is presently in acquisition, but during its construction about 100 field wires broke, because of chemical corrosion induced by the atmospheric humidity. On the basis of the experience gained with this chamber we decided to build a new one, equipped with a different type of wires less sensitive to corrosion. The choice of the new wire required a deep inspection of its characteristics and one of the main tools for doing this is a system for measuring the wire tension by means of the resonant frequency technique, which is described in this paper. The system forces the wires to oscillate by applying a sinusoidal signal at a known frequency, and then measures the variation of the capacitance between a wire and a common ground plane as a function of the external signal frequency. We present the details of the measuring system and the results obtained by scanning the mechanical tensions of two samples of MEG II CDCH wires and discuss the possible improvements of the experimental apparatus and of the measuring technique.Comment: Ten pages, twelve figures, to be submitted to Nuclear Instruments and Methods

Muon polarization in the MEG experiment: Predictions and measurements

The MEG experiment makes use of one of the world’s most intense low energy muon beams, in order to search for the lepton flavour violating process μ+ → e+ γ. We determined the residual beam polarization at the thin stopping target, by measuring the asymmetry of the angular distribution of Michel decay positrons as a function of energy. The initial muon beam polarization at the production is predicted to be Pμ = −1 by the StandardModel (SM) with massless neutrinos. We estimated our residual muon polarization to be (formula presented) at the stopping target, which is consistent with the SM predictions when the depolarizing effects occurring during the muon production, propagation and moderation in the target are taken into account. The knowledge of beam polarization is of fundamental importance in order to model the background of our μ+ → e+ γ search induced by themuon radiative decay: (formula presented)

Measurement of the radiative decay of polarized muons in the MEG experiment

We studied the radiative muon decay (Formula presented.) by using for the first time an almost fully polarized muon source. We identified a large sample ((Formula presented.) 13,000) of these decays in a total sample of (Formula presented.) positive muon decays collected in the MEG experiment in the years 2009–2010 and measured the branching ratio (Formula presented.) for (Formula presented.) and (Formula presented.) , consistent with the Standard Model prediction. The precise measurement of this decay mode provides a basic tool for the timing calibration, a normalization channel, and a strong quality check of the complete MEG experiment in the search for (Formula presented.) process

Search for the lepton flavour violating decay μ+→ e +γ with the full dataset of the MEG experiment: MEG Collaboration

The final results of the search for the lepton flavour violating decay μ+→ e +γ based on the full dataset collected by the MEG experiment at the Paul Scherrer Institut in the period 2009–2013 and totalling 7.5 × 10 14 stopped muons on target are presented. No significant excess of events is observed in the dataset with respect to the expected background and a new upper limit on the branching ratio of this decay of B(μ+→ e +γ) < 4.2 × 10 - 13 (90 % confidence level) is established, which represents the most stringent limit on the existence of this decay to date

Search for the lepton flavour violating decay μ+→ e +γ with the full dataset of the MEG experiment: MEG Collaboration

none84siThe final results of the search for the lepton flavour violating decay mu(+) -> e(+)gamma based on the full dataset collected by the MEG experiment at the Paul Scherrer Institut in the period 2009-2013 and totalling 7.5x10(14) stopped muons on target are presented. Nosignificant excess of events is observed in the dataset with respect to the expected background and a new upper limit on the branching ratio of this decay of B(mu(+) -> e(+) gamma) < 4.2 x 10(-13) (90 % confidence level) is established, which represents the most stringent limit on the existence of this decay to date.Baldini, A.M.; Bao, Y.; Baracchini, E.; Bemporad, C.; Berg, F.; Biasotti, M.; Boca, G.; Cascella, M.; Cattaneo, P.W.; Cavoto, G.; Cei, F.; Cerri, C.; Chiarello, G.; Chiri, C.; Corvaglia, A.; de Bari, A.; De Gerone, M.; Doke, T.; D’Onofrio, A.; Dussoni, S.; Egger, J.; Fujii, Y.; Galli, L.; Gatti, F.; Grancagnolo, F.; Grassi, M.; Graziosi, A.; Grigoriev, D.N.; Haruyama, T.; Hildebrandt, M.; Hodge, Z.; Ieki, K.; Ignatov, F.; Iwamoto, T.; Kaneko, D.; Kang, T.I.; Kettle, P.-R.; Khazin, B.I.; Khomutov, N.; Korenchenko, A.; Kravchuk, N.; Lim, G.M.A.; Maki, A.; Mihara, S.; Molzon, W.; Mori, Toshinori; Morsani, F.; Mtchedilishvili, A.; Mzavia, D.; Nakaura, S.; Nardò, R.; Nicolò, D.; Nishiguchi, H.; Nishimura, M.; Ogawa, S.; Ootani, W.; Orito, S.; Panareo, M.; Papa, A.; Pazzi, R.; Pepino, A.; Piredda, G.; Pizzigoni, G.; Popov, A.; Raffaelli, F.; Renga, F.; Ripiccini, E.; Ritt, S.; Rossella, M.; Rutar, G.; Sawada, R.; Sergiampietri, F.; Signorelli, G.; Simonetta, M.; Tassielli, G.F.; Tenchini, F.; Uchiyama, Y.; Venturini, M.; Voena, C.; Yamamoto, A.; Yoshida, K.; You, Z.; Yudin, Yu. V.; Zanello, D.Baldini, A. M.; Bao, Y.; Baracchini, E.; Bemporad, C.; Berg, F.; Biasotti, M.; Boca, Gianluigi; Cascella, M.; Cattaneo, P. W.; Cavoto, G.; Cei, F.; Cerri, C.; Chiarello, G.; Chiri, C.; Corvaglia, A.; DE BARI, Antonio; De Gerone, M.; Doke, T.; D’Onofrio, A.; Dussoni, S.; Egger, J.; Fujii, Y.; Galli, L.; Gatti, F.; Grancagnolo, F.; Grassi, M.; Graziosi, A.; Grigoriev, D. N.; Haruyama, T.; Hildebrandt, M.; Hodge, Z.; Ieki, K.; Ignatov, F.; Iwamoto, T.; Kaneko, D.; Kang, T. I.; Kettle, P. R.; Khazin, B. I.; Khomutov, N.; Korenchenko, A.; Kravchuk, N.; Lim, G. M. A.; Maki, A.; Mihara, S.; Molzon, W.; Mori, Toshinori; Morsani, F.; Mtchedilishvili, A.; Mzavia, D.; Nakaura, S.; Nardo', Roberto; Nicolò, D.; Nishiguchi, H.; Nishimura, M.; Ogawa, S.; Ootani, W.; Orito, S.; Panareo, M.; Papa, A.; Pazzi, R.; Pepino, A.; Piredda, G.; Pizzigoni, G.; Popov, A.; Raffaelli, F.; Renga, F.; Ripiccini, E.; Ritt, S.; Rossella, M.; Rutar, G.; Sawada, R.; Sergiampietri, F.; Signorelli, G.; Simonetta, M.; Tassielli, G. F.; Tenchini, F.; Uchiyama, Y.; Venturini, M.; Voena, C.; Yamamoto, A.; Yoshida, K.; You, Z.; Yudin, Y. u. V.; Zanello, D