Emission and coherent control of Levitons in graphene.

Flying qubits encode quantum information in propagating modes instead of stationary discrete states. Although photonic flying qubits are available, the weak interaction between photons limits the efficiency of conditional quantum gates. Conversely, electronic flying qubits can use Coulomb interactions, but the weaker quantum coherence in conventional semiconductors has hindered their realization. In this work, we engineered on-demand injection of a single electronic flying qubit state and its manipulation over the Bloch sphere. The flying qubit is a Leviton propagating in quantum Hall edge channels of a high-mobility graphene monolayer. Although single-shot qubit readout and two-qubit operations are still needed for a viable manipulation of flying qubits, the coherent manipulation of an itinerant electronic state at the single-electron level presents a highly promising alternative to conventional qubits.

Scaling behavior of electron decoherence in a graphene Mach-Zehnder interferometer.

Over the past 20 years, many efforts have been made to understand and control decoherence in 2D electron systems. In particular, several types of electronic interferometers have been considered in GaAs heterostructures, in order to protect the interfering electrons from decoherence. Nevertheless, it is now understood that several intrinsic decoherence sources fundamentally limit more advanced quantum manipulations. Here, we show that graphene offers a unique possibility to reach a regime where the decoherence is frozen and to study unexplored regimes of electron interferometry. We probe the decoherence of electron channels in a graphene quantum Hall PN junction, forming a Mach-Zehnder interferometer1,2, and unveil a scaling behavior of decay of the interference visibility with the temperature scaled by the interferometer length. It exhibits a remarkable crossover from an exponential decay at higher temperature to an algebraic decay at lower temperature where almost no decoherence occurs, a regime previously unobserved in GaAs interferometers.

Quantum Hall Valley Splitters and a Tunable Mach-Zehnder Interferometer in Graphene.

Graphene is a very promising test bed for the field of electron quantum optics. However, a fully tunable and coherent electronic beam splitter is still missing. We report the demonstration of electronic beam splitters in graphene that couple quantum Hall edge channels having opposite valley polarizations. The electronic transmission of our beam splitters can be tuned from zero to near unity. By independently setting the beam splitters at the two corners of a graphene p-n junction to intermediate transmissions, we realize a fully tunable electronic Mach-Zehnder interferometer. This tunability allows us to unambiguously identify the quantum interferences due to the Mach-Zehnder interferometer, and to study their dependence with the beam-splitter transmission and the interferometer bias voltage. The comparison with conventional semiconductor interferometers points toward universal processes driving the quantum decoherence in those two different 2D systems, with graphene being much more robust to their effect.

[Whole brain radiation therapy for brain metastases: Advantages and controversies]. / Radiothérapie encéphalique en totalité des métastases cérébrales : intérêts et controverses dans le cadre d'un référentiel.

Whole brain radiation therapy is the angular stone of the brain metastasis radiation therapy. This treatment allows reaching two goals, potentially curative for in place metastasis and prophylactic in the rest of brain tissue. However, these two advantages can be disputed and in light of the same data opposite conclusions could be drawn.

[Difficulties encountered and solutions found when implementing stereotactic radiotherapy of non-small cell lung cancer]. / Radiothérapie thoracique en conditions stéréotaxiques : difficultés rencontrées lors de la mise en route et solutions proposées.

The aim of this paper is to describe the difficulties encountered when implementing stereotactic radiotherapy of non-small cell lung cancer (T1-T2, N0, M0) using a voluntary breath-hold technique. From 25/03/2010 to 22/02/2011, eight patients with a non-small cell lung cancer were selected for treatment. CT images were obtained with the patient maintaining breath-hold using a spirometer. Treatment was delivered when the patient maintains this level of breath-hold. Treatment was performed with a 4 MV and 10 MV photon beams from a linear accelerator Varian 2100CS, equipped with a 120 leaves collimator. 60 Gy or 48 Gy were delivered, in four sessions, to the 80% isodose. The planning target volume (PTV) was defined by adding a 5mm margin to the internal target volume (ITV), the ITV corresponding to the gross tumour volume (GTV) plus a 3mm margin. CTV is considered equal to GTV. The non-understanding of the gating technique, the great number of beams and the limited breath-hold times led to the failure of some treatments. It can be explained by some patients insufficient respiratory abilities and the low dose rate of one of the beams used for treatment, thus forcing some radiation fields to be delivered in two or three times. Implementing such a technique can be limited by the patients' physical abilities and the materials used. Some solutions were found: a training phase more intense with a coaching of the breath-hold technique more precise, or the use of an abdominal compression device.

[Whole brain radiation with supplementary boost for patients for unique brain metastasis from a primitive lung cancer]. / Expérience de l'irradiation encéphalique totale avec escalade de dose focalisée pour le traitement des métastases cérébrales uniques d'un carcinome bronchopulmonaire.

PURPOSE: To assess the potential benefit of a boost in patients treated with whole brain irradiation by a conventional linear accelerator for lung cancer solitary brain metastasis. PATIENTS AND METHODS: From 2002 to 2006, a retrospective analysis was carried out from 64 unselected consecutive patients with secondary brain metastasis from lung cancer, treated with whole brain irradiation without surgical resection. Thirty patients (47%) received a boost in their brain metastases. Three potential prognostic factors were studied: sex, RPA score and improvement of neurological symptoms after radiotherapy. An analysis was conducted to determine whether an additional dose may improve survival in the absence of surgical resection. RESULTS: The mean follow-up was 4.9 months. The median overall survival was 8.5 months (6.4 to 10.7 months). The total dose of radiotherapy was the only significant prognostic factor for overall survival. The median overall survival was 6.2 months for patients without additional radiation versus 11.2 months for patients receiving a boost dose (p=0.011). Sex, RPA score and improvement of neurological symptoms after radiotherapy were not found as prognostic factors for overall survival. CONCLUSIONS: Boost delivered after whole brain radiation therapy by a conventional particle accelerator may provide a benefit in selected patients, especially for centres that do not have radiotherapy techniques in stereotactic conditions. This warrants further prospective assessment.

[Malignant gliomas]. / Gliomes cérébraux.

Glial tumors represent 2000 to 3000 new cases per year in France and 75% of them are of high grade. Recent understanding of the molecular biology of these tumors revealed the importance of 1p19q codeletion and mgMT promotor methylation. Radiotherapy also recently evolved with the progress in medical imaging which allows a better definition of the target volumes. Even modest, therapeutic progress is based on chemoradiotherapy with temozolomide and on the development of non-coplanar conformational radiotherapy. Knowledge and precise evaluation of potential late effects of our treatments is necessary due to actual improvement of survival with chemoradiotherapy in glioblastoma.

[Management for 145 cases of Merkel cell carcinoma]. / Prise en charge de 145 cas de carcinomes à cellules de Merkel.

PURPOSE: Merkel cell carcinoma (MCC)/primary cutaneous neuroendocrine carcinoma is a rare and aggressive malignant tumor. Optimal therapeutic strategy has not yet been established. PATIENTS AND METHODS: Management of 145 patients from five centres was analysed. These data included ages, pathological stages, disease sites, histological and treatment details. Cause-specific (CSS) and overall survivals (OS) were analyzed by the Log-rank and Kaplan-Meier methods. RESULTS: Median age was 78 years (47-95.2). We experienced 37 local, 37 regional and 15 distant relapses. In case of relapse, salvage therapy has been proposed whenever the general state of health condition of patient permitted it. CONCLUSION: Our results for the treatment of relapse encourage multidisciplinary approach. Multicenter prospective trials are still needed to clarify and validate the optimal strategy.

[Normal tissue tolerance to external beam radiation therapy: brain and hypophysis]. / Dose de tolérance à l'irradiation des tissus sains: encéphale et hypophyse.

Anticancer treatments-induced central nervous system neurotoxicity has become a major problem in recent years. Real advances in therapeutic results for cancer treatments have improved patients' survival. Nowadays, central nervous system radiation therapy is widely prescribed, both for palliative and curative treatments in the management of malignant or benign tumors. Recent data on tolerance of normal central nervous system to radiation therapy are reviewed here, early and delayed radiation-induced effects are described and dose recommendations are suggested for clinical practice.

[Management of Merkel cell carcinoma: Role of radiotherapy in elderly patients]. / Prise en charge des carcinomes à cellules de Merkel : place de la radiothérapie chez les patients âgés.

PURPOSE: Merkel cell carcinoma carcinoma (MCC) or primary cutaneous neuroendocrine carcinoma is a rare and aggressive malignancy affecting elderly. Optimal therapeutic strategy has not yet been established in elderly patients. PATIENTS AND METHODS: From March 1996 to March 2007, 29 patients with Merkel cell carcinoma of were treated at the University Hospital of Amiens, France. Adjuvant radiotherapy (RT) was performed for 14 patients (50%) on the tumor bed with margins of 3 to 5cm, an average dose of 46Gy (30-60Gy), by 2Gy per fraction. Ten of them also received RT to the lymph node area at mean dose of 44.3Gy (26-50Gy). Duration of RT was 35 days. A retrospective analysis was conducted to better evaluate survival and prognostic factors. RESULTS: Median overall survival (OS) was 18.9 months (3-122) and the median time to progression (MTP) 5.5 months (1-26). At 5 years, OS for irradiated patients was 47% (IC95: 12-82%) versus 27% (IC95: 5-49%) in cases of surgery alone (p=0.032). The most frequent sites of recurrence were nodal (34.5%), local (24.1%) and metastatic (17.2%). For patients over 70 years, eight (36.5%) were free of disease at last news, 8 (36.5%) had died from cancer and six from other causes (27%). In this subgroup, MTP was 6 months (2-19) and median OS of 19 months (4-87). There was no acute toxicity greater than grade 2. CONCLUSION: Although limited by a retrospective analysis, this report suggests an advantage of postoperative RT for patients with MCC. It combined low toxicity and improvement of survival. Prospective multicenter trials are needed to clarify and validate the optimal strategy.

[The axial orientation of the phalanges following the curling up of the fingers]. / L'orientation axiale des phalanges consécutive à l'enroulement des doigts.

This study follows and modestly completes those by Dubousset and Kapandji concerning the phenomena of axial (or longitudinal) rotation of the phalanges combined with flexion-extension of the fingers. Our analysis of the orientation of axial rotation of the skeletal elements of the digital chain, in relation to each other and during digito-palmar flexion was supported by simple observation, impressions in silicone paste, study of anatomical preparations, three-dimensional computed tomography. The index finger and middle finger tend to supinate. The ring finger undergoes virtually no rotation and the distal end of the little finger tends to pronate. These phenomena, essential for good adaptation to grip and fine manipulation must be taken into account by rehabilitation physicians when the amplitude of these movements are limited by immobilisation or disease.

Treatment of high-risk gestational trophoblastic disease with chemotherapy combinations containing cisplatin and etoposide.

The authors have treated 22 patients with high-risk gestational trophoblastic disease (GTD) by cisplatin-etoposide-containing combinations. Sixteen patients were treated with dactinomycin, platinum, and etoposide combination (APE regimen) and six patients had platinum and etoposide combination (PE regimen). Fourteen patients were treated for resistant or relapsing GTD after first-line therapy, and eight patients initially. All 22 patients were high risk according to the World Health Organization prognostic score values. Sustained complete remission was achieved in 19 patients (86%). All eight patients who received treatment as initial therapy were cured (100%) whereas only 11 patients were cured among the 14 patients who failed prior chemotherapy (78%). Hematologic and renal toxicities were limited and no treatment-related deaths occurred in this group of patients. Cisplatin and etoposide could be more widely used in chemotherapeutic combinations for high-risk gestational trophoblastic disease.

[Venous drainage of Littler's neurovascular pedicle flap]. / Le drainage veineux du lambeau à pédicule neurovasculaire de Littler.

The antegrade transosseous injection of the digital veins, followed by dissection enables the authors to analyse the role of various networks in drainage of the pulp. The satellite veins of the digital artery in the finger are probably not involved. The venous return of the pulp is constituted by an anatomical continuity between the superficial palmar network and the common digital veins. A narrow anastomotic channel is demonstrated in the commissure between these two systems.