Spontaneous osteo-dural fistulae of petrous bone posterior wall

SummaryObjectiveTo raise awareness of the possibility of spontaneous temporal bone cerebrospinal fistula in case of clear retrotympanic effusion.Case reportA 63-year-old man with no particular history presented with unilateral spontaneous right retrotympanic clear effusion. CT found defects in the posterior part of the right temporal bone, in contact with arachnoid granulations, with no other visible abnormalities.Discussion/ConclusionUnilateral clear retrotympanic effusion in an adult subject should, apart from serous otitis media, suggest possible cerebrospinal fistula. In the absence of otologic or traumatic history, arachnoid granulation is one possible etiology, inducing spontaneous cerebrospinal fluid leakage when facing the temporal bone. Diagnosis is suggested by bone defects in the tegmen tympani or posterior wall of the temporal bone on CT, with the adjacent mastoid cavities filled with fluid. Pneumococcal vaccination and early surgical repair of the fistula should be performed to avoid neuromeningeal infection

Solution-Processable Graphene Oxide as an Efficient Hole Injection Layer for High Luminance Organic Light-Emitting Diodes

The application of solution-processable graphene oxide (GO) as hole injection layer in organic light-emitting diodes (OLEDs) is demonstrated. High luminance of over 53,000 cd m-2 is obtained at only 10 V. The results will unlock a route of applying GO in flexible OLEDs and other electrode applications.Comment: 14 pages, 3 figures, 1 tabl

L'ombre d'un doute ? Interactions perceptivo-motrices lors de tâches de close-shadowing auditive et audio-visuelles

International audienceOne classical argument in favor of a functional role of the motor system in speech perception comes from the close shadowing task in which a subject has to identify and to repeat as quickly as possible an auditory speech stimulus. The fact that close shadowing can occur very rapidly and much faster than manual identification of the speech target is taken to suggest that perceptually-induced speech representations are already shaped in a motor-compatible format. Another argument is provided by audiovisual interactions often interpreted as referring to a multisensory-motor framework. In this study, we attempted to combine these two paradigms by testing whether the visual modality could speed motor response in a close-shadowing task. To this aim, both oral and manual responses were evaluated during the perception of auditory and audio-visual speech stimuli, clear or embedded in white noise. Overall, oral responses were much faster than manual ones, but it also appeared that they were less accurate in noise, which suggests that motor representations evoked by the speech input could be rough at a first processing stage. In the presence of acoustic noise, the audiovisual modality led to both faster and more accurate responses than the auditory modality. No interaction was however observed between modality and response. Altogether, these results are interpreted within a two-stage sensory-motor framework, in which the auditory and visual streams are integrated together and with internally generated motor representations before a final decision may be available.Un argument classique en faveur des théories motrices de la perception de la parole provient du paradigme de " close-shadowing " (répétition rapide). Le fait que cette tâche de close-shadowing entraîne des réponses orales bien plus rapides qu'en réponses manuelles suggère en effet un codage des représentations perceptives dans un format moteur, compatible avec une réponse orale. Un autre argument est apporté par les interactions audio-visuelles lors de la perception de parole, souvent interprétées en référence à un couplage fonctionnel entre audition, vision et motricité. Dans cette étude, nous avons combiné ces deux paradigmes de manière à tester si la modalité visuelle pouvait induire des réponses motrices plus rapides lors d'une tâche de close-shadowing. Pour ce faire, différentes tâches de catégorisation orale et manuelle de stimuli de parole présentés auditivement ou audio-visuellement, en présence ou non d'un bruit blanc, ont été réalisées. De manière générale, les réponses orales ont été plus rapides que les réponses manuelles, mais aussi moins précises, notamment dans le bruit, ce qui suggère que la représentation motrice induite par la stimulation pourrait être peu précise dans un premier niveau de traitement. En présence d'un bruit acoustique, la modalité audiovisuelle s'est avérée à la fois plus rapide et plus précise que la modalité auditive. Aucune interaction entre le mode de réponse et la modalité de présentation des stimuli n'a cependant été observée. Nous interprétons l'ensemble de ces résultats dans un cadre théorique proposant l'existence de boucles perceptivo-motrices, dans lesquelles les entrées auditives et visuelles seraient intégrées et reliées à la génération interne de représentations motrices préalablement au processus final de décision

L'ombre d'un doute ? Interactions perceptivo-motrices lors de tâches de close-shadowing auditive et audio-visuelles

International audienceOne classical argument in favor of a functional role of the motor system in speech perception comes from the close shadowing task in which a subject has to identify and to repeat as quickly as possible an auditory speech stimulus. The fact that close shadowing can occur very rapidly and much faster than manual identification of the speech target is taken to suggest that perceptually-induced speech representations are already shaped in a motor-compatible format. Another argument is provided by audiovisual interactions often interpreted as referring to a multisensory-motor framework. In this study, we attempted to combine these two paradigms by testing whether the visual modality could speed motor response in a close-shadowing task. To this aim, both oral and manual responses were evaluated during the perception of auditory and audio-visual speech stimuli, clear or embedded in white noise. Overall, oral responses were much faster than manual ones, but it also appeared that they were less accurate in noise, which suggests that motor representations evoked by the speech input could be rough at a first processing stage. In the presence of acoustic noise, the audiovisual modality led to both faster and more accurate responses than the auditory modality. No interaction was however observed between modality and response. Altogether, these results are interpreted within a two-stage sensory-motor framework, in which the auditory and visual streams are integrated together and with internally generated motor representations before a final decision may be available.Un argument classique en faveur des théories motrices de la perception de la parole provient du paradigme de " close-shadowing " (répétition rapide). Le fait que cette tâche de close-shadowing entraîne des réponses orales bien plus rapides qu'en réponses manuelles suggère en effet un codage des représentations perceptives dans un format moteur, compatible avec une réponse orale. Un autre argument est apporté par les interactions audio-visuelles lors de la perception de parole, souvent interprétées en référence à un couplage fonctionnel entre audition, vision et motricité. Dans cette étude, nous avons combiné ces deux paradigmes de manière à tester si la modalité visuelle pouvait induire des réponses motrices plus rapides lors d'une tâche de close-shadowing. Pour ce faire, différentes tâches de catégorisation orale et manuelle de stimuli de parole présentés auditivement ou audio-visuellement, en présence ou non d'un bruit blanc, ont été réalisées. De manière générale, les réponses orales ont été plus rapides que les réponses manuelles, mais aussi moins précises, notamment dans le bruit, ce qui suggère que la représentation motrice induite par la stimulation pourrait être peu précise dans un premier niveau de traitement. En présence d'un bruit acoustique, la modalité audiovisuelle s'est avérée à la fois plus rapide et plus précise que la modalité auditive. Aucune interaction entre le mode de réponse et la modalité de présentation des stimuli n'a cependant été observée. Nous interprétons l'ensemble de ces résultats dans un cadre théorique proposant l'existence de boucles perceptivo-motrices, dans lesquelles les entrées auditives et visuelles seraient intégrées et reliées à la génération interne de représentations motrices préalablement au processus final de décision

Control of defect-mediated tunneling barrier heights in ultrathin MgO films

The impact of oxygen vacancies on local tunneling properties across rf-sputtered MgO thin films was investigated by optical absorption spectroscopy and conducting atomic force microscopy. Adding O$_2$ to the Ar plasma during MgO growth alters the oxygen defect populations, leading to improved local tunneling characteristics such as a lower density of current hotspots and a lower tunnel current amplitude. We discuss a defect-based potential landscape across ultrathin MgO barriers.Comment: 4 pages, 4 figure

Study of molecular spin-crossover complex Fe(phen)2(NCS)2 thin films

We report on the growth by evaporation under high vacuum of high-quality thin films of Fe(phen)2(NCS)2 (phen=1,10-phenanthroline) that maintain the expected electronic structure down to a thickness of 10 nm and that exhibit a temperature-driven spin transition. We have investigated the current-voltage characteristics of a device based on such films. From the space charge-limited current regime, we deduce a mobility of 6.5x10-6 cm2/V?s that is similar to the low-range mobility measured on the widely studied tris(8-hydroxyquinoline)aluminium organic semiconductor. This work paves the way for multifunctional molecular devices based on spin-crossover complexes

The Skull Vibration-Induced Nystagmus Test of Vestibular Function—A Review

A 100-Hz bone-conducted vibration applied to either mastoid induces instantaneously a predominantly horizontal nystagmus, with quick phases beating away from the affected side in patients with a unilateral vestibular loss (UVL). The same stimulus in healthy asymptomatic subjects has little or no effect. This is skull vibration-induced nystagmus (SVIN), and it is a useful, simple, non-invasive, robust indicator of asymmetry of vestibular function and the side of the vestibular loss. The nystagmus is precisely stimulus-locked: it starts with stimulation onset and stops at stimulation offset, with no post-stimulation reversal. It is sustained during long stimulus durations; it is reproducible; it beats in the same direction irrespective of which mastoid is stimulated; it shows little or no habituation; and it is permanent—even well-compensated UVL patients show SVIN. A SVIN is observed under Frenzel goggles or videonystagmoscopy and recorded under videonystagmography in absence of visual-fixation and strong sedative drugs. Stimulus frequency, location, and intensity modify the results, and a large variability in skull morphology between people can modify the stimulus. SVIN to 100 Hz mastoid stimulation is a robust response. We describe the optimum method of stimulation on the basis of the literature data and testing more than 18,500 patients. Recent neural evidence clarifies which vestibular receptors are stimulated, how they cause the nystagmus, and why the same vibration in patients with semicircular canal dehiscence (SCD) causes a nystagmus beating toward the affected ear. This review focuses not only on the optimal parameters of the stimulus and response of UVL and SCD patients but also shows how other vestibular dysfunctions affect SVIN. We conclude that the presence of SVIN is a useful indicator of the asymmetry of vestibular function between the two ears, but in order to identify which is the affected ear, other information and careful clinical judgment are needed

Tri-critical point and suppression of the Shastry-Sutherland phase in Ce2_{2}Pd2_{2}Sn by Ni doping

Structural, magnetization and heat capacity measurements were performed on Ce$_2$(Pd$_{1-x}$Ni$_x$)$_2$Sn ($0 \leq x \leq 0.25$) alloys, covering the full range of the Mo$_2$FeB$_2$ structure stability. In this system, the two transitions observed in Ce$_2$Pd$_2$Sn (at $T_N=4.8$\,K and $T_C=2.1$\,K respectively) converge into a tri-critical point at $T_{cr}\approx 3.4$\,K for $x\approx 0.3$, where the intermediate antiferromagnetic AF phase is suppressed. The $T_N(x)$ phase boundary decrease is due to an incipient Kondo screening of the Ce-4f moments and local atomic disorder in the alloy. Both mechanisms affect the formation of Ce-magnetic dimers on which the Shastry-Sutherland lattice (SSL) builds up. On the contrary, the $T_C(x)$ transition to the ferromagnetic ground state increases as a consequence of the weakening of the AF-SSL phase. Applied magnetic field also suppresses the AF phase like in the stoichiometric compound.Comment: 6 pages, 8 figure

Photoluminescence properties of rare earth (Nd, Yb, Sm, Pr)-doped CeO2 pellets prepared by solid-state reaction

Several structural and optical properties of ceria (band gap, refractive index and lattice parameter) make this material very promising for applications in optoelectronics and photovoltaics. In this paper, we show that CeO2 can be efficiently functionalized by doping with trivalent rare earth ions to give rise to photon management properties. The trivalent ions can be successfully inserted by solid-state reaction of the elementary oxide powders. By combining the information obtained from the absorbance spectra with that of the PL excitation spectra, we demonstrate the presence of the trivalent ions in CeO2 and provide insight in the electronic level structure and transfer mechanism. In particular, we prove that both the complex absorption spectra and the energy transfer mechanisms cannot be fully explained without considering the presence of isolated Ce3+ ions in CeO2