Efficient Microwave Photon-to-Electron Conversion in a High-Impedance Quantum Circuit.

We demonstrate an efficient and continuous microwave photon-to-electron converter with large quantum efficiency (83%) and low dark current. These unique properties are enabled by the use of a high kinetic inductance disordered superconductor, granular aluminium, to enhance light-matter interaction and the coupling of microwave photons to electron tunneling processes. As a consequence of strong coupling, we observe both linear and nonlinear photon-assisted processes where two, three, and four photons are converted into a single electron at unprecedentedly low light intensities. Theoretical predictions, which require quantization of the photonic field within a quantum master equation framework, reproduce well the experimental data. This experimental advancement brings the foundation for high-efficiency detection of individual microwave photons using charge-based detection techniques.

Microwave Signature of Topological Andreev level Crossings in a Bismuth-based Josephson Junction.

Demonstrating the topological protection of Andreev states in Josephson junctions is an experimental challenge. In particular the telltale 4π periodicity expected for the current phase relation has remained elusive, because of fast parity breaking processes. It was predicted that low temperature ac susceptibility measurements could reveal the topological protection of quantum spin Hall edge states by probing their low energy Andreev spectrum at finite frequency. We have performed such a microwave probing of a phase-biased Josephson junction built around a bismuth nanowire, a predicted second order topological insulator, and which was previously shown to host one-dimensional ballistic edge states. We find absorption peaks at the Andreev level crossings, whose temperature and frequency dependencies point to protected topological crossings with an accuracy limited by the electronic temperature of our experiment.

Spin-Orbit Coupling at the Level of a Single Electron.

We utilize electron counting techniques to distinguish a spin-conserving fast tunneling process and a slower process involving spin flips in AlGaAs/GaAs-based double quantum dots. By studying the dependence of the rates on the interdot tunnel coupling of the two dots, we find that as many as 4% of the tunneling events occur with a spin flip related to spin-orbit coupling in GaAs. Our measurement has a fidelity of 99% in terms of resolving whether a tunneling event occurred with a spin flip or not.

Measuring the Degeneracy of Discrete Energy Levels Using a GaAs/AlGaAs Quantum Dot.

We demonstrate an experimental method for measuring quantum state degeneracies in bound state energy spectra. The technique is based on the general principle of detailed balance and the ability to perform precise and efficient measurements of energy-dependent tunneling-in and -out rates from a reservoir. The method is realized using a GaAs/AlGaAs quantum dot allowing for the detection of time-resolved single-electron tunneling with a precision enhanced by a feedback control. It is thoroughly tested by tuning orbital and spin degeneracies with electric and magnetic fields. The technique also lends itself to studying the connection between the ground-state degeneracy and the lifetime of the excited states.

Microwave Emission from Hybridized States in a Semiconductor Charge Qubit.

We explore the microwave radiation emitted from a biased double quantum dot due to the inelastic tunneling of single charges. Radiation is detected over a broad range of detuning configurations between the dot energy levels, with pronounced maxima occurring in resonance with a capacitively coupled transmission line resonator. The power emitted for forward and reverse resonant detuning is found to be in good agreement with a rate equation model, which considers the hybridization of the individual dot charge states.

Measurement of quantum noise in a carbon nanotube quantum dot in the Kondo regime.

The current emission noise of a carbon nanotube quantum dot in the Kondo regime is measured at frequencies ν of the order or higher than the frequency associated with the Kondo effect k(B)T (K)/h, with TK the Kondo temperature. The carbon nanotube is coupled via an on-chip resonant circuit to a quantum noise detector, a superconductor-insulator-superconductor junction. We find for hν ≈ k(B)T(K) a Kondo effect related singularity at a voltage bias eV ≈ hν, and a strong reduction of this singularity for hν ≈ 3k(B)T(K), in good agreement with theory. Our experiment constitutes a new original tool for the investigation of the nonequilibrium dynamics of many-body phenomena in nanoscale devices.

Emission and absorption quantum noise measurement with an on-chip resonant circuit.

Using a quantum detector, a superconductor-insulator-superconductor junction, we probe separately the emission and absorption noise in the quantum regime of a superconducting resonant circuit at equilibrium. At low temperature the resonant circuit exhibits only absorption noise related to zero point fluctuations, whereas at higher temperature emission noise is also present. By coupling a Josephson junction, biased above the superconducting gap, to the same resonant circuit, we directly measure the noise power of quasiparticles tunneling through the junction at two resonance frequencies. It exhibits a strong frequency dependence, consistent with theoretical predictions.

Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres.

X-ray absorption spectroscopy is an element-specific technique for probing the local atomic-scale environment around an absorber atom. It is widely used to investigate the structures of liquids and solids, being especially valuable for characterization of solid-supported catalysts. Reported cell designs are limited in capabilities-to fluorescence or transmission and to static or flowing atmospheres, or to vacuum. Our goal was to design a robust and widely applicable cell for catalyst characterizations under all these conditions-to allow tracking of changes during genesis and during operation, both under vacuum and in reactive atmospheres. Herein, we report the design of such a cell and a demonstration of its operation both with a sample under dynamic vacuum and in the presence of gases flowing at temperatures up to 300 °C, showing data obtained with both fluorescence and transmission detection. The cell allows more flexibility in catalyst characterization than any reported.

Structured Ni catalysts on porous anodic alumina membranes for methane dry reforming: NiAl2O4 formation and characterization.

This communication presents the successful design of a structured catalyst based on porous anodic alumina membranes for methane dry reforming. The catalyst with a strong Ni-NiAl2O4 interaction shows both excellent activity and stability.

Hippocampal polymorph neurons are the cells of origin for ipsilateral association and commissural afferents to the dentate gyrus.

Neurons in the polymorph layer of the hippocampal dentate hilus were found to be the cells of origin for ipsilateral association and commissural projections to the dentate gyrus. Both afferent systems terminate in the proximal one-third of the stratum moleculare. The polymorph layer is the primary target for noradrenergic, serotonergic and cholinergic input to the hippocampal dentate region. It is hypothesized that one or all of these afferent groups affect hippocampal function through synaptic modification of the defined polymorph afferent system.

Indium-111 antimyosin scintigraphy before and after coronary bypass surgery: unexpected preoperative myocardial uptakes.

The present study was designed to evaluate 111In-antimyosin scintigraphy in detecting pre- and post-operative myocardial infarction in patients undergoing coronary artery bypass surgery. Fab antimyosin scintigraphy has been shown to be sensitive and specific in detecting myocardial necrosis and to be potentially valuable in situations where other criteria are not reliable. In a previous study, postoperative antimyosin uptakes occurred in 82% of the studied patients. Sixteen consecutive patients with an indication of coronary artery surgery were assessed by preoperative coronary angiography, serial electrocardiograms, and myocardial scanning with 111Indium-labeled antimyosin antibodies performed before and after operation. In four patients, a recent myocardial infarction (1 to 3 months) was detected with an accurate localization when compared to the classic criteria of myocardial infarction. One more patient with a 21-year old myocardial infarction showed an intense uptake whereas there was no recent acute coronary event. Four other patients had an unexpected preoperative uptake, since there were no acute coronary events in their medical history. All preoperative scintigraphic uptakes were still present on the second scan performed postoperatively in these nine patients. Only one patient showed a new postoperative uptake when compared to the preoperative scan which was normal; this postoperative septal infarct was confirmed by a postoperative coronary angiography. Extracardiac uptakes (sternum and ribs) were frequently observed after operation and might hamper the interpretation of postoperative scintigrams. Unexpected preoperative uptakes may be related to non diagnosed small necrosis. A preoperative reference scan is required for an accurate interpretation of a postoperative 111In-antimyosin uptake. Moreover, extracardiac uptakes may limit the interpretation of perioperative cardiac damage.

Diagnosis of cerebral metastases by thallium 201.

We have studied the diagnostic potential of thallium 201 in cerebral metastases. Twenty-five patients with one or several metastases have been investigated with two tracers, 201T1 and sodium pertechnetate (99Tcm). With 201T1, all the cases gave a positive result within ten minutes of injection. In 88%, the definition was better, and in five cases (20%) small metastases which were invisible with 99Tcm could be demonstrated with 201T1. This radiotracer seems to promise greater diagnostic precision with an examination time of only 30 minutes.

Cinegammography and 3-D emission tomoscintigraphy for evaluation of revascularized mandibular bone grafts: a preliminary report.

The following reports a study conducted to investigate a scintigraphic monitoring procedure for bone free flap in mandibular reconstruction. This procedure is based on the one hand, on vascular and bone cinegammography, and on the other hand, on vascular and bone 3-D tomoscintigraphy. We used a prospective cohort study design. All patients who underwent free flap mandibular reconstruction from April 1993 to April 1998 in the Salpêtrière University Hospital, France (20 cases) have been evaluated in relation to this scintigraphic procedure. Vascular and bone scintigraphy were performed within the second week after surgery during 2 consecutive days. All images were read by one author (J.- Y. B.), who did not know the skin status of the flap. The results were compared with the viability of revascularized bone grafts as evaluated by the skin status and Greenberg classification based on bone radiographs three months after reconstruction. Vascular cinegammography seems to be closely related to anastomosis patency. Bone cinegammography gives appreciable information on bone viability. 3-D vascular tomoscintigraphy remains difficult to interpret. 3-D bone tomoscintigraphy gives precise information on the viability of the different segments of the bone flap. These results suggest that vascular and bone 3-D tomoscintigraphy coupled with cinegammography have an excellent prognostic value. In the event of partial failure it can give information on the location of the impaired patency and on the osseous fragment which has lost any viability.

[Indium III monoclonal antimyosin antibody scintigraphy for the detection of chronic myocardial infarction apart from the acute phase]. / Scintigraphie aux anticorps monoclonaux antimyosine marqués à l'indium 111 pour la détection de l'infarctus du myocarde en dehors de la phase aiguë.

Fab antimyosin scintigraphy has been shown to be sensitive and specific in detecting acute myocardial necrosis. This study was designed to evaluate the preoperative frequency of Indium-111 (In-111) antimyosin myocardial uptake in patients scheduled for coronary artery bypass surgery. The scintigraphic results were compared with other criteria of myocardial infarction (MI). Sixteen consecutive patients were included. Recent MI (1 to 3 months) were detected in four patients, with an accurate localization in three cases when compared to the classic criteria for MI. Two more patients had old Q wave MI: one did not show any uptake in the territory of MI whereas the second patient with a 21 year old infarct without recent acute coronary events showed an intense uptake consistent with the ECG and angiographic localization. Four other patients with stable angina showed limited uptakes that were unexpected, since there were no acute coronary events in their medical history, and ECG. Their left ventricle angiography were considered as normal. In these four cases, the scintigraphic location corresponded to a territory supplied by an occluded coronary artery (n = 2) or by a coronary artery with a tight stenosis requiring a bypass graft (n = 2). These antimyosin uptakes are probably related to small necroses which did not modify the ECG and did not alter the ventricular segmental wall motion. We conclude: 1) recent MI are detected by In-111 antimyosin scintigraphy; 2) In-111 antimyosin uptake may occur in patients without a diagnosis of recent myocardial infarction and correspond to older MI or limited necroses without detectable changes of the ECG and left ventricle angiography.

[Study of variations in the regional blood volume in the limbs under effort or thermal stress in arterial conditions (author's transl)]. / Etude des variations du volume sanguin régional au niveau des membres sous stimulus d'effort ou thermique dans les artériopathies.

The method of measuring the regional blood volume by labelling the erythrocytes with Technetium-99m has been applied to two groups of patients suffering either from arteritis of the lower limbs or from Raynaud's syndrome. A reduction in the blood volume during physical effort has been observed in arteritis of the lower limbs, followed by a rise of varying extent depending on the severity of the condition. In some cases surgical treatment has produced a particularly obvious effect on the variations in the blood volume, accompanied by a favourable clinical evolution. It has been found in patients suffering from Raynaud's syndrome that the reduction in the blood volume continues after the end of the exposition of the patients' hands to a temperature of 10 degrees C.

[Measurement of multiregional blood volumes: a cerebral vascular autoregulatory phenomenon (author's transl)]. / Mesure du volume sanguin multi-régional: phénomène d'autorégulation vasculaire cérébral.

The variations in regional cerebral blood volume (RCBV) during controlled severe hypotension induced by sodium nitroprusside were studied in a series of 29 patients with aneurysms (14), meningiomas (6) and arteriovenous malformations. Two characteristic variations were noted. The RCBV and mean blood pressure (MPB) vary inversely, this type of variation being known as "Active variation". When pathological lesions are present the RCBV and MBP are modified in the same direction in the regions affected and this is called "Passive variation". A quantitative study in 21 patients showed that in the healthy regions there was a change from the active to the passive mode of variation for a MBP situated between 44 and 52 mm of mercury.

[Trans-tympanic aeration in mastoiditis. Study of 42 cases (author's transl)]. / L'aérateur transtympanique dans les mastoïdites.

The authors review the diagnostic protocol of mastoiditis based upon 382 cases with 1.3% errors (histological confirmation). Up to the present time, mastoidectomy was the only treatment which could be envisaged. In a new series of 90 cases, 48 constituted the control group and 42 the study group, trans-tympanic drains were inserted routinely in the latter. It was thus possible to avoid mastoidectomy in 62% of cases in the study group (evaluation based upon the number of ears). The period of postoperative observation was on average 8 months. No complications related to the drain were seen. Up to the present time, there exist no precise criteria which may be used to decide between insertion of a drain or mastoidectomy from the outset. Insertion of a drain must thus be considered as a therapeutic test, justified by its harmlessness and simplicity.

[Spontaneous meningeal fistula of the middle ear detected during insertion of a trans-tympanic aerator (author's transl)]. / Fistule méningée spontanée de l'oreille moyenne découverte par la mise en place d'un aérateur trans-tympanique.

A remarkable case of spontaneous meningeal fistula of the middle ear is described, the lesion being detected during insertion of a trans-tympanic aerator in an 80-year-old woman. The totally exceptional nature of this case is emphasized, and the therapeutic problems that it gave rise to exposed. Instead of the suprapetrous approach, theoretically more logical, the less dangerous inferior approach was employed, with a subsequent successful result. Biochemical tests should be conducted in all cases of serous otitis, where there is secretion of an abundant amount of clear fluid of atypical appearance.

[Rare tumors of the septum. 8 reported cases (author's transl)]. / Tumeurs rares de la cloison: 8 cas rapportés.

The authors present 8 cases of rare tumors of the nasal septum and define a number of characteristic points on the basis of each of them. The following are presented: --a malignant nevus, the rarety of E.N.T. sites of such tumors is emphasized, as well as important role of immunotherapy in their treatment, alongside surgery and radio-therapy. --a keratoacanthoma, difficult in terms of differential diagnosis from a basal cell carcinoma. -- a cavernous hemangioma, excision of which must be wide if recurrence is to be avoided. --one very hemorrhagic mixed tumor. --one case of pseudo tumoral tuberculosis in a woman with no known past history of tuberculous disease. --one very painful glomus tumor, radical treatment of which is surgical, in preference to radiotherapy. --two cylindromas of the septum, one taking the form of a large, angiomatous polyp, which puts in question the name of cystic adenoid carcinoma, suggested for these non-cutaneous tumors.

[Midline congenital fistulas of the nose. Fourteen cases (author's transl)]. / Fistules congénitales médianes du nez. (à propos de quatorze observations).

The authors report 14 cases of midline congenital fistulas of the nose. Early diagnosis of the abnormality and its deep prolongations are necessary in order to avoid delayed presentation by infectious complications, which may be grave. Anteroposterior tomograms, in Gosserez view, in general provide precise information concerning the extent. In order to limit aesthetic problems, surgical treatment, without prejudice to total excision, should give preference to concealed transcolumellar incisions extended if necessary to the nostrils. This approach offers extensive manaeuvrability and makes it possible to perform a rhinoplasty if necessary.