Non-invasive on-skin sensors for brain machine interfaces with epitaxial graphene.

Objective. Brain-machine interfaces are key components for the development of hands-free, brain-controlled devices. Electroencephalogram (EEG) electrodes are particularly attractive for harvesting the neural signals in a non-invasive fashion.Approach.Here, we explore the use of epitaxial graphene (EG) grown on silicon carbide on silicon for detecting the EEG signals with high sensitivity.Main results and significance.This dry and non-invasive approach exhibits a markedly improved skin contact impedance when benchmarked to commercial dry electrodes, as well as superior robustness, allowing prolonged and repeated use also in a highly saline environment. In addition, we report the newly observed phenomenon of surface conditioning of the EG electrodes. The prolonged contact of the EG with the skin electrolytes functionalize the grain boundaries of the graphene, leading to the formation of a thin surface film of water through physisorption and consequently reducing its contact impedance more than three-fold. This effect is primed in highly saline environments, and could be also further tailored as pre-conditioning to enhance the performance and reliability of the EG sensors

Beam test evaluation of electromagnetic calorimeter modules made from proton-damaged PbWO_4 crystals

The performance of electromagnetic calorimeter modules made of proton-irradiated PbWO_4 crystals has been studied in beam tests. The modules, similar to those used in the Endcaps of the CMS electromagnetic calorimeter (ECAL), were formed from 5×5 matrices of PbWO_4 crystals, which had previously been exposed to 24 GeV protons up to integrated fluences between 2.1× 10^(13) and 1.3× 10^(14) cm^(−2). These correspond to the predicted charged-hadron fluences in the ECAL Endcaps at pseudorapidity η = 2.6 after about 500 fb^(−1) and 3000 fb^(−1) respectively, corresponding to the end of the LHC and High Luminosity LHC operation periods. The irradiated crystals have a lower light transmission for wavelengths corresponding to the scintillation light, and a correspondingly reduced light output. A comparison with four crystals irradiated in situ in CMS showed no significant rate dependence of hadron-induced damage. A degradation of the energy resolution and a non-linear response to electron showers are observed in damaged crystals. Direct measurements of the light output from the crystals show the amplitude decreasing and pulse becoming faster as the fluence increases. The latter is interpreted, through comparison with simulation, as a side-effect of the degradation in light transmission. The experimental results obtained can be used to estimate the long term performance of the CMS ECAL

Charged Particle Induced Etching and Functionalization of Two-Dimensional Materials

Focused electron beam induced deposition and etching (FEBID and FEBIE) are direct-write nanofabrication techniques in which an electron beam is used to achieve nanostructure functionalization, etching or deposition. Either alone or in combination with in situ plasmas, these techniques can also be used to accelerate reactions that occur in ambient environment, with simultaneous high-resolution imaging. Here, we describe our recent work on etching, functionalization and directed assembly of a range of nanoand two-dimensional materials using temperature-dependent FEBIE experiments in an environmental scanning electron microscope (ESEM). As examples of the application of these techniques, we demonstrate processes for assembling arrays of nanodiamonds that can be used as magnetic field sensors, as well as for controlled etching of hexagonal boron nitride (hBN) and black phosphorus (BP)

En reconstruction mammaire : intérêt du dépistage du portage de Staphylococcus aureus dans la prévention de l’infection du site opératoire

National audienceThe incidence of prosthesis infections after breast reconstruction is of the order of 4% to 13% according to the literature. In surgical patients, Staphylococcus aureus (S. aureus) is the bacterial species most often responsible for surgical site infections. In cardiac surgery, screening for carriage of S. aureus and preoperative decontamination are carried out routinely before prosthetic surgery. We retrospectively reviewed data from patients at our institution between January 2011 and December 2013. Our series showed that the prosthesis infection rates were in the range of 5.92% in 2008 with an ISO rate of S. aureus 3.61%. Routine screening for prosthetic reconstructions was performed to assess the impact of preoperative decontamination patients in carriers of S. aureus. This screening was done in 381 patients: 17.8% of patients were carriers of S. aureus ; 11 patients have an ISO (or an incidence rate of 2.88%) ; 5 patients have an ISO S. aureus (an incidence of S. aureus ISO 1.3%). The introduction of the screening process, allowed a drop of 5.92% ISO rate at 1.46% with a passage of S. aureus SSI rates of 3, 60% to 0.72%. In the near future, studies are needed to confirm these encouraging results, to demonstrate the efficacy of preoperative decontamination in carriers of S. aureus patients before laying prosthesis

Evaluation of a urine pooling strategy for the rapid and cost-efficient prevalence classification of schistosomiasis

A key epidemiologic feature of schistosomiasis is its focal distribution, which has important implications for the spatial targeting of preventive chemotherapy programs. We evaluated the diagnostic accuracy of a urine pooling strategy using a point-of-care circulating cathodic antigen (POC-CCA) cassette test for detection of Schistosoma mansoni, and employed simulation modeling to test the classification accuracy and efficiency of this strategy in determining where preventive chemotherapy is needed in low-endemicity settings.; We performed a cross-sectional study involving 114 children aged 6-15 years in six neighborhoods in Azaguié Ahoua, south Côte d'Ivoire to characterize the sensitivity and specificity of the POC-CCA cassette test with urine samples that were tested individually and in pools of 4, 8, and 12. We used a Bayesian latent class model to estimate test characteristics for individual POC-CCA and quadruplicate Kato-Katz thick smears on stool samples. We then developed a microsimulation model and used lot quality assurance sampling to test the performance, number of tests, and total cost per school for each pooled testing strategy to predict the binary need for school-based preventive chemotherapy using a 10% prevalence threshold for treatment.; The sensitivity of the urine pooling strategy for S. mansoni diagnosis using pool sizes of 4, 8, and 12 was 85.9%, 79.5%, and 65.4%, respectively, when POC-CCA trace results were considered positive, and 61.5%, 47.4%, and 30.8% when POC-CCA trace results were considered negative. The modeled specificity ranged from 94.0-97.7% for the urine pooling strategies (when POC-CCA trace results were considered negative). The urine pooling strategy, regardless of the pool size, gave comparable and often superior classification performance to stool microscopy for the same number of tests. The urine pooling strategy with a pool size of 4 reduced the number of tests and total cost compared to classical stool microscopy.; This study introduces a method for rapid and efficient S. mansoni prevalence estimation through examining pooled urine samples with POC-CCA as an alternative to widely used stool microscopy

Search for dark matter produced in association with heavy-flavor quark pairs in proton-proton collisions at √s = 13 TeV

A search is presented for an excess of events with heavy-flavor quark pairs (tt and bb) and a large imbalance in transverse momentum in data from proton–proton collisions at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 2.2fb^(−1) collected with the CMS detector at the CERN LHC. No deviations are observed with respect to standard model predictions. The results are used in the first interpretation of dark matter production in tt and bb final states in a simplified model. This analysis is also the first to perform a statistical combination of searches for dark matter produced with different heavy-flavor final states. The combination provides exclusions that are stronger than those achieved with individual heavy-flavor final states

Measurement of the B^± Meson Nuclear Modification Factor in Pb-Pb Collisions at √S_(NN) = 5.02 TeV

The differential production cross sections of B^± mesons are measured via the exclusive decay channels B^± → J/ψK^ ±→ μ^+μ^−K^± as a function of transverse momentum in pp and Pb-Pb collisions at a center-of-mass energy √S_(NN) = 5.02  TeV per nucleon pair with the CMS detector at the LHC. The pp(Pb-Pb) data set used for this analysis corresponds to an integrated luminosity of 28.0  pb^(-1) (351  μb^(-1)). The measurement is performed in the B^± meson transverse momentum range of 7 to 50  GeV/c, in the rapidity interval |y| < 2.4. In this kinematic range, a strong suppression of the production cross section by about a factor of 2 is observed in the Pb-Pb system in comparison to the expectation from pp reference data. These results are found to be roughly compatible with theoretical calculations incorporating beauty quark diffusion and energy loss in a quark-gluon plasma

Constraints on the double-parton scattering cross section from same-sign W boson pair production in proton-proton collisions at √s = 8 TeV

A first search for same-sign WW production via double-parton scattering is performed based on proton-proton collision data at a center-of-mass energy of 8 TeV using dimuon and electron-muon final states. The search is based on the analysis of data corresponding to an integrated luminosity of 19.7 fb^(−1). No significant excess of events is observed above the expected single-parton scattering yields. A 95% confidence level upper limit of 0.32 pb is set on the inclusive cross section for same-sign WW production via the double-parton scattering process. This upper limit is used to place a 95% confidence level lower limit of 12.2 mb on the effective double-parton cross section parameter, closely related to the transverse distribution of partons in the proton. This limit on the effective cross section is consistent with previous measurements as well as with Monte Carlo event generator predictions