Neuromorphic function learning with carbon nanotube based synapses.

The principle of using nanoscale memory devices as artificial synapses in neuromorphic circuits is recognized as a promising way to build ground-breaking circuit architectures tolerant to defects and variability. Yet, actual experimental demonstrations of the neural network type of circuits based on non-conventional/non-CMOS memory devices and displaying function learning capabilities remain very scarce. We show here that carbon-nanotube-based memory elements can be used as artificial synapses, combined with conventional neurons and trained to perform functions through the application of a supervised learning algorithm. The same ensemble of eight devices can notably be trained multiple times to code successively any three-input linearly separable Boolean logic function despite device-to-device variability. This work thus represents one of the very few demonstrations of actual function learning with synapses based on nanoscale building blocks. The potential of such an approach for the parallel learning of multiple and more complex functions is also evaluated.

Anodic bonded 2D semiconductors: from synthesis to device fabrication.

Two-dimensional semiconductors are increasingly relevant for emergent applications and devices, notably for hybrid heterostructures with graphene. We fabricate few-layer, large-area (a few tens of microns across) samples of the III-VI semiconductors GaS, GaSe and InSe using the anodic bonding method and characterize them by simultaneous use of optical microscopy, atomic force microscopy and Raman spectroscopy. Two-terminal devices with a gate are constructed to show the feasibility of applications based on these.

High quality 2D crystals made by anodic bonding: a general technique for layered materials.

Anodic bonding of nanolayers is an easy technique based on a simple apparatus, which has already proven successful in application in the fabrication of high quality graphene. Here we demonstrate its extension to the fabrication of high quality nanolayers from several layered materials. The strengths of this technique are its high throughput rate and ease of application. All fabrication parameters are controllable and need to be determined carefully. We report optimal parameters found for nine layered materials. In general, using optimal parameters results in high quality 2D layers, in most cases much larger than those obtained by 'Scotch tape' microcleavage, with higher yields and which are easily transferable to other substrates. Moreover the samples obtained are clean and the good optical contrast of these layers on the glass substrate makes their identification very easy. This is thus the technique of choice for making nanolayers in the laboratory from any layered material.

Identification of a strong genetic background for progressive cardiac conduction defect by epidemiological approach.

INTRODUCTION: Progressive cardiac conduction defect (PCCD) is a frequent disease attributed to degeneration and fibrosis of the His bundle. Over the past years, gene defects have been identified demonstrating that PCCD could be a genetic disease. The aim of this study was to show a familial aggregation for PCCD using a genetic epidemiological approach to improve in fine genetic knowledge of the transmission of the disease. METHODS AND RESULTS: Using the French social security number, the authors have been able to determine the city of birth of the 6667 patients implanted with a pacemaker (PM) for PCCD between 1995 and 2005 in the western part of France. The authors then mapped the frequency of PM implantations for PCCD. A large heterogeneity of the frequency of the disease has been observed, with a frequency of 0.21% in the major city (Nantes) ranging up to 2.28% in specific parishes. Familial studies performed in the parishes with the highest frequency of the disease allowed the authors to identify five large families with PCCD. Clinical investigations demonstrated phenotype heterogeneity between families. Three patterns have been differentiated. CONCLUSIONS: This study demonstrates a disparate geographical repartition of the frequency of PM implantation in the area of the authors at least in part related to a hereditary factor. The identification of five large families affected by PCCD using epidemiological approach underlines the existence of a major genetic background in PCCD.

Surgical or medical treatment for thrombus straddling the patent foramen ovale: impending paradoxical embolism? Report of four clinical cases and literature review.

BACKGROUND: Thrombus straddling the patent foramen ovale (TSFO) is a rare event. It occurs in the presence of pulmonary embolism and can be responsible for paradoxical embolism. The aim of this report is to guide the optimal choice of treatment for TSFO in different clinical contexts. METHODS: A PubMed search was conducted of articles published between 1985, when the first TSFO was reported, and 2007. We identified 93 cases of TSFO diagnosed by echocardiography, nine of which were excluded because of lack of information. We analysed data from these 84 patients plus a further four seen at three French cardiology departments. RESULTS: The patients' mean age was 58 years. Pulmonary embolism was present in 94% of cases, and was severe in 34%. Paradoxical embolism, before or after treatment, was found in 44% of cases. Fifty-five patients were treated surgically, 21 were treated with heparin, and 11 received thrombolysis. The mortality rates for the treatments were 13, 14 and 36%, respectively. Patients who received heparin were older (60+/-17 years) and had more strokes (11/21) than the surgical group (56+/-15 years, 14/55). The group that received thrombolysis was more likely to have haemodynamic compromise. CONCLUSION: Medical treatment with heparin tends to be used as a second option in patients with more frequent comorbidities and strokes but the mortality rate is similar to that in the surgical group. Surgery seems to be justified in the prevention of paradoxical embolism. Thrombolysis is more frequently chosen in the higher risk group and is associated with the greatest mortality.