Une approche pour des capteurs d'alarmes intelligents dans les réseaux

Dans le cadre de la gestion des fautes dans les réseaux de télécommunication, nous proposons une approche nouvelle, utilisant des outils et méthodes développés pour l'observation et la vérification dans le domaine des systèmes répartis. Nous utilisons notamment les réseaux de Petri et les ordres partiels pour exprimer les causalités existantes entre pannes et alarmes. Nous exposons notre démarche et définissons un modèle de propagation des pannes et des alarmes

An electrically driven and readable molecular monolayer switch using a solid electrolyte

The potential application of molecular switches as active elements in information storage has been demonstrated through numerous reported works. Importantly for devices, such switching capability has also been observed on self-assembled monolayers (SAMs). SAMs of electro-active molecules have been exploited in the last few years as electrochemical switches. Typically, the state of these switches could be read out through their optical and/or magnetic responses. These output reading processes are difficult to integrate into devices and in addition there is a need to use liquid environments to switch the redox-active molecular systems. Here, we overcome both these challenges using an ion-gel as electrolyte medium achieving an unprecedented solid state device based on a single molecular layer. Further, electrochemical impedance has been successfully exploited as the output of the system.We thank R. Pfattner for his help and F. J. del Campo for providing the silicon mold. We acknowledge the financial support of the EU projects ERC StG 2012-306826 e-GAMES, ITN iSwitch (GA no. 642196) and CIG (PCIG10-GA-2011-303989), the Networking Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), the DGI (Spain) with project BE-WELL CTQ2013-40480-R and the Generalitat de Catalunya with project 2014-SGR-17. E. M. acknowledges the Materials Science PhD program of UAB and N.C the JdC program.Peer reviewe

Improving the dielectric properties of ethylene-glycol alkanethiol self-assembled monolayers.

Self-assembled monolayers (SAMs) can be formed at the interface between solids and fluids, and are often used to modify the surface properties of the solid. One of the most widely employed SAM systems is exploiting thiol-gold chemistry, which, together with alkane-chain-based molecules, provides a reliable way of SAM formation to modify the surface properties of electrodes. Oligo ethylene-glycol (OEG) terminated alkanethiol monolayers have shown excellent antifouling properties and have been used extensively for the coating of biosensor electrodes to minimize nonspecific binding. Here, we report the investigation of the dielectric properties of COOH-capped OEG monolayers and demonstrate a strategy to improve the dielectric properties significantly by mixing the OEG SAM with small concentrations of 11-mercaptoundecanol (MUD). The monolayer properties and composition were characterized by means of impedance spectroscopy, water contact angle, ellipsometry and X-ray photoelectron spectroscopy. An equivalent circuit model is proposed to interpret the EIS data and to determine the conductivity of the monolayer. We find that for increasing MUD concentrations up to about 5% the resistivity of the SAM steadily increases, which together with a considerable decrease of the phase of the impedance, demonstrates significantly improved dielectric properties of the monolayer. Such monolayers will find widespread use in applications which depend critically on good dielectric properties such as capacitive biosensor

“We can’t handle things we don’t know about”: perceived neurorehabilitation challenges for Malawian paediatric cerebral malaria survivors

Background We sought to identify perceptions of neurorehabilitation challenges for paediatric cerebral malaria (CM) survivors post-hospital discharge at Queen Elizabeth Central Hospital (QECH) in Blantyre, Malawi. Methods An exploratory approach was used to qualitatively investigate the perceived neurorehabilitation challenges for paediatric CM survivors. Data were collected through semi-structured in-depth interviews (IDIs) and focus group discussions (FGDs). Eighteen data-gathering sessions were conducted with 38 total participants, including 3 FGDs with 23 primary caregivers, 11 IDIs with healthcare workers at QECH, and 4 IDIs with community-based rehabilitation workers (CRWs). Results FGDs revealed that caregivers lack important knowledge about CM and fear recurrence of CM in their children. Post-CM children and families experience substantial stigma and sociocultural barriers to integrating into their community and accessing neurorehabilitative care. At a community-level, rehabilitation infrastructure, including trained staff, equipment, and programmes, is extremely limited. Rehabilitation services are inequitably accessible, and community-based rehabilitation remains largely unavailable. Conclusions There is an urgent need to establish further training of rehabilitation personnel at all levels and to build accessible rehabilitation infrastructure in Malawi for post-CM patients. Additional work is required to expand this study across multiple regions for a holistic understanding of neurorehabilitation needs

“We can’t handle things we don’t know about”: perceived neurorehabilitation challenges for Malawian paediatric cerebral malaria survivors

Background: We sought to identify perceptions of neurorehabilitation challenges for paediatric cerebral malaria (CM) survivors post-hospital discharge at Queen Elizabeth Central Hospital (QECH) in Blantyre, Malawi. Methods: An exploratory approach was used to qualitatively investigate the perceived neurorehabilitation challenges for paediatric CM survivors. Data were collected through semi-structured in-depth interviews (IDIs) and focus group discussions (FGDs). Eighteen data-gathering sessions were conducted with 38 total participants, including 3 FGDs with 23 primary caregivers, 11 IDIs with healthcare workers at QECH, and 4 IDIs with community-based rehabilitation workers (CRWs). Results: FGDs revealed that caregivers lack important knowledge about CM and fear recurrence of CM in their children. Post-CM children and families experience substantial stigma and sociocultural barriers to integrating into their community and accessing neurorehabilitative care

Label-free electrochemical impedance biosensor to detect human interleukin-8 in serum with sub-pg/ml sensitivity

Biosensors with high sensitivity and short time-to-result that are capable of detecting biomarkers in body fluids such as serum are an important prerequisite for early diagnostics in modern healthcare provision. Here, we report the development of an electrochemical impedance-based sensor for the detection in serum of human interleukin-8 (IL-8), a pro-angiogenic chemokine implicated in a wide range of inflammatory diseases. The sensor employs a small and robust synthetic non-antibody capture protein based on a cystatin scaffold that displays high affinity for human IL-8 with a KD of 35 ± 10 nM and excellent ligand specificity. The change in the phase of the electrochemical impedance from the serum baseline, ∆θ(ƒ), measured at 0.1 Hz, was used as the measure for quantifying IL-8 concentration in the fluid. Optimal sensor signal was observed after 15 min incubation, and the sensor exhibited a linear response versus logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml. A detection limit of around 90 fg/ml, which is significantly lower than the basal clinical levels of 5-10 pg/ml, was observed. Our results are significant for the development of point-of-care and early diagnostics where high sensitivity and short time-to-results are essential

Clinical Utilization of the FilmArray Meningitis/Encephalitis (ME) Multiplex Polymerase Chain Reaction (PCR) Assay

Objective: To assess the clinical utilization and performance of the FilmArray® Meningitis/Encephalitis (ME) multiplex polymerase chain reaction (PCR) panel in a hospital setting.Background: Rapid diagnosis and treatment of central nervous system (CNS) infections are critical to reduce morbidity and mortality. The ME panel is a Food and Drug Administration (FDA) approved rapid multiplex PCR assay that targets 14 bacteria, viruses, and fungi. Previous studies show an overall agreement of 93–99% between the ME panel and conventional diagnostic testing. However, few studies have evaluated the clinical implementation of the ME assay, which is available for routine use at our institution.Methods: We performed a single center retrospective chart review of inpatients who underwent ME panel testing from August 2016 to May 2017. Clinical, radiologic, and laboratory data were reviewed to determine the clinical significance of results. Indication for lumbar puncture (LP), time to results of the ME panel, and duration of antimicrobial therapy were evaluated.Results: Seven hundred and five inpatients underwent ME testing, of whom 480 (68.1%) had clinical suspicion for CNS infection with 416 (59.0%) receiving empiric antimicrobial treatment for CNS infection. The median time-to-result of the ME panel was 1.5 h (IQR, 1.4–1.7). Overall agreement between the ME panel results and clinico-laboratory assessment was 98.2%. Forty-five patients tested positive by ME, of which 12 (26.6%) were determined likely to be clinically insignificant.Conclusions: Routine availability of the ME panel led to overutilization of diagnostic test ordering, as demonstrated by the fact that over one-third of ME panel tests performed were ordered for patients with little or no suspicion for CNS infection. The median time from LP to ME panel result was 1.5 h (IQR, 1.4–1.7). The ME panel's rapid turn-around time contributed to the overuse of the test. Approximately one-quarter of positive ME results were deemed clinically insignificant, though the impact of these positive results requires additional evaluation. Twenty-four and forty-eight hours after the ME panel resulted, 68 and 25% of patients started on empiric therapy remained on antibiotics, respectively. The median time from diagnosis to discontinuation and/or narrowing of antibiotic coverage was 25.6 h (IQR, 3.6–42.5). Further consideration of the appropriate indications for use of the ME panel in clinical settings is required

Ion transport and electron transfer at self-assembled alkylthiolgold monolayers

The electrical and electrochemical properties of self-assembled n-alkylthiol monolayers (SAMs) on gold are important if SAMs are to be used as molecular building blocks in biomimetic membranes and in micro- or nano-electronics. Ion transport and electron transfer at SAM/electrolyte interfaces are two important processes which have been characterized by cyclic voltammetry and a.c. impedance spectroscopy. Ion transport from an aqueous phase to the hydrophobic SAM region has been addressed by investigating the insulating properties of a wide variety of X(CH2)nS/Au SAMs (X = CH3, OH, CO2H and CF 3, and n = 7, 9, 11, 15). It was established that when the phase angle at a frequency characteristic of ion diffusion processes ( i.e. 1 Hz) is >88°, the SAM is defect-free and obeys the Helmholtz ideal capacitor model. However, when &phiv;1HZ < 88°, the SAM is no longer an ionic insulator and ion/water penetration from the electrolyte into the SAM hydrophobic region is observed. The behavior of the phase angle with frequency was used to characterize the permeability of SAMs to electrolyte ions (K+, H2PO4 -, and HPO42-) as a function of the applied d.c. potential. A critical potential, Vc, was identified for each type of SAM corresponding to a transition from an insulating state to a more permeable state. When X = CH3, V c becomes more cathodic with increasing chainlength, i.e. Vc = -0.15 V (vs. Ag/AgCl) for n = 7, -0.25 V for n = 9, 11, and -0.35 V for n = 15. The SAM ionic permeability can also be modulated by maintaining n constant (15) and by varying the terminal group X. Vc is considerably more anodic for hydrophilic SAM/electrolyte interfaces (+0.25 V vs . Ag/AgCl for X = OH and + 0.15 V for X = CO2H) than for hydrophobic interfaces (-0.35 V for X = CH3). The kinetics of electron transfer at CH3(CH2)15CH3 SAMs have been investigated by a.c. impedance spectroscopy at various d.c. overpotentials with three redox couples, Ru(NH3)63+/2+, Fe(CN)63-/4-, and Co(

Une approche pour des capteurs d'alarmes intelligents dans les réseaux

Dans le cadre de la gestion des fautes dans les réseaux de télécommunication, nous proposons une approche nouvelle, utilisant des outils et méthodes développés pour l'observation et la vérification dans le domaine des systèmes répartis. Nous utilisons notamment les réseaux de Petri et les ordres partiels pour exprimer les causalités existantes entre pannes et alarmes. Nous exposons notre démarche et définissons un modèle de propagation des pannes et des alarmes