Characterisation of an Electrostatic Vibration Harvester

Harvesting energy from ambient vibration is proposed as an alternative to storage based power supplies for autonomous systems. The system presented converts the mechanical energy of a vibration into electrical energy by means of a variable capacitor, which is polarized by an electret. A lumped element model is used to study the generator and design a prototype. The device has been micromachined in silicon, based on a two-wafer process. The prototype was successfully tested, both using an external polarization source and an electret.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

The Arabs in Malta : 870-1150

Οἱ παῖδες Ἄγαρ ἀθέου is the phrase used by the mid-12th-century anonymous poet exiled on Melitogaudos to describe his neighbours on the island. As the publication of the long lament by this poet did not give much attention to his unneighbourly neighbours, it is the object of this communication to take a closer look at this community, addressing the related questions of who, when and under what conditions were they there, in the light of what was happening at the time in Sicily, and to the South, in North Africa. We conclude with a hypothetical reconstruction of developments in Malta during the Arab period.peer-reviewe

Motion-Based Generators for Industrial Applications

Scaling down of electronic systems has generated a large interest in the research on miniature energy sources. In this paper a closer look is given to the use of vibration based scavengers in industrial environments, where waste energy is abundantly available as engine related vibrations or large amplitude motions. The modeling of mechanical generators resulted in the design and realization of two prototypes, based on electromagnetic and electrostatic conversion of energy. Although the prototypes are not yet optimized against size and efficiency, a power of 0.3 mW has been generated in a 5 Hz motion with a 0.5 meter amplitude.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

PARTITION OF THE ORGANOCHLORINE INSECTICIDE LINDANE INTO THE HUMAN SPERM SURFACE INDUCES MEMBRANE DEPOLARIZATION AND CALCIUM INFLUX

The effects of the insecticide lindane (the gamma-isomer of 1,2,3,4,5,6-hexachlorocyclohexane) on membrane potential, cytosolic free Ca2+ concentration ([Ca2+]i) and surface biophysical properties were studied in human spermatozoa. The insecticide induces rapid, transient and reproducible membrane depolarization and opening of voltage-dependent Ca2+ channels leading to an increase in [Ca2+]i. In contrast with the effect in somatic cells, lindane did not affect gamma-aminobutyric acid receptor-linked Cl- currents. Ca2+ and K+ currents were found to drive lindane-induced membrane depolarization and repolarization respectively, whereas Na+ and Cl- fluxes appear not to have a role in the phenomenon. The insecticide was still able to produce membrane depolarization both in the combined absence of extracellular Ca2+ and Na+ and in high-K+ buffer, suggesting that lindane alters the membrane dipole potential. In agreement with this, Laurodan and Prodan fluorescence spectroscopy revealed that lindane partition into the sperm plasma membrane lowers water molecular dynamics in the uppermost region of the membrane external leaflet, probably as the result of reordering of water dipoles. We propose that the first effect of lindane partitioning into the sperm plasma membrane is a change in the membrane dipole potential, which results in the activation of membrane-located Ca2+-influx pathways

Effect of PAF on polyrnorphonuclear leucocyte plasma membrane polarity: a fluorescence study

The effect of PAF on the plasma membrane polarity of polymorphonuclear leukocytes (PMNs) was investigated by measuring the steady-state fluorescence emission spectra of 2-dimethylamino(6-1auroyl) naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surrounding. Laurdan shows a marked steady-state emission blue-shift in non-polar solvents, with respect to polar solvents. Our results demonstrate that PAF (10−7 M) induces a blue shift of the fluorescence emission spectra of Laurdan. These changes are blocked in the presence of the PAF antagonist, L-659,989. Our data indicate that the interaction between PAF and PMNs is accompanied by a decrease in polarity in the hydrophobic-hydrophilic interface of the plasma membrane

Design of Cloud Robotic Services for Senior Citizens to Improve Independent Living and Personal Health Management

A cloud robotics solution was designed and initially tested with a mobile robotic platform and a smart environment, in order to provide health-care management services to senior citizens and improve their independent living. The solution was evaluated in terms of Quality of Service (QoS) and tested in the realistic scenario of the DomoCasa Living Lab, Peccioli, Italy. In particular, a medication reminding service, a remote home monitoring and a user indoor localization algorithm were outsourced in the cloud and provided to the robots, users and carers. The system acquired data from a smart environment and addressed the robot to the user for service delivery. Experiments showed a service's Reliability of Response at least of the 0.04 % and a Time of Response of the same order of magnitude of the processing time required by the user localization algorithm

Is open tracheotomy performed by residents in otorhinolaryngology a safe procedure? a retrospective cohort study.

Surgical or percutaneous tracheotomy is one of the commonest operations in the ENT practice and one of the first procedures to be taught to residents. No study exists that demonstrates the safety of this surgical procedure performed by unexperienced surgeons. The purpose was to compare outcomes of tracheotomies performed by supervised residents and surgeons in terms of postoperative complications and mortality, and identify risk factors for the onset of complications. Retrospective cohort study. Otolaryngology-Head and Neck Surgery Department, University of Florence, Italy. We included all patients undergoing tracheotomy from July 2008 to January 2013 and compared tracheotomies performed by supervised residents or surgeons. During the study period, 304 patients were submitted to tracheotomy. Patients operated by surgeons had a significantly higher number of tracheal rings fracture (p = 0.05), subcutaneous emphysema (p = 0.003) and tracheostomy tube displacement (p = 0.003), while supervised residents had a higher number of tracheitis/pneumonia (p = 0.04) as early complications. Patients operated by supervised residents had a significantly higher number of tube obstructions as late complication (p = 0.04). Using multivariate model, risk factors for early postoperative complications were male sex (p = 0.04) and delayed time to substitution with cuffless tube (p = 0.01), while only a trend to statistical significance was observed for urgent tracheotomies concerning the risk for late postoperative complications (p = 0.08). The current practice where residents perform tracheotomies supervised by a surgeon should not be disheartened. Our study demonstrates that it is safe and does not lead to higher risk of complications nor negatively affects the quality of care