Electric motor wheel assembly

A motor wheel assembly with a radial flux brushless electric motor with a seat on the stator interrupting the sequence of stator electromagnets suitabel for housing a caliper of a braking system

Microelectrode arrays of diamond-insulated graphitic channels for real time detection of exocytotic events from cultured chromaffin cells and slices of adrenal glands

A microstructured graphitic 4x4 multielectrode array was embedded in a single crystal diamond substrate (4x4 {uG-SCD MEA) for real-time monitoring of exocytotic events from cultured chromaffin cells and adrenal slices. The current approach relies on the development of a parallel ion beam lithographic technique, which assures the time effective fabrication of extended arrays with reproducible electrode dimensions. The reported device is suitable for performing amperometric and voltammetric recordings with high sensitivity and temporal resolution, by simultaneously acquiring data from 16 rectangularly shaped microelectrodes (20x3.5 um^2) separated by 200 um gaps. Taking advantage of the array geometry we addressed the following specific issues: i) detect both the spontaneous and KCl-evoked secretion simultaneously from several chromaffin cells directly cultured on the device surface, ii) resolve the waveform of different subsets of exocytotic events, iii) monitoring quantal secretory events from thin slices of the adrenal gland. The frequency of spontaneous release was low (0.12 Hz and 0.3 Hz respectively for adrenal slices and cultured cells) and increased up to 0.9 Hz after stimulation with 30 mM KCl in cultured cells. The spike amplitude as well as rise and decay time were comparable with those measured by carbon fiber microelectrodes and allowed to identify three different subsets of secretory events associated to "full fusion" events, "kiss and-run" and "kiss-and-stay" exocytosis, confirming that the device has adequate sensitivity and time resolution for real-time recordings. The device offers the significant advantage of shortening the time to collect data by allowing simultaneous recordings from cell populations either in primary cell cultures or in intact tissues

Electric motor wheel assembly

A motor wheel assembly with a radial flux brushless electric motor with a seat on the stator interrupting the sequence of stator electromagnets suitabel for housing a caliper of a braking syste

Cambios en la heterogeneidad del paisaje y organización espacial de bosques nativos en Patagonia, Argentina

Native forests in Patagonia have been influenced by human activities since the beginning of the past century. Nevertheless, the availability of aerial photographs to conduct analysis of changes at a landscape level due to anthropic factors is generally restricted to the last decades. Therefore this study was aimed to detect changes of the forest landscape heterogeneity during the last thirty years in the northwest region of Chubut, the middle-located Patagonian province, and to study spatial patterning of forest landscapes. For the first goal, we focused on a 2,000 ha landscape unit with prevailing Austrocedrus chilensis forests. In 466 ha covered by these forests, 41% of this area was negatively affected by forest fires, timber logging followed by livestock grazing and substitution with pine plantations. In contrast, growth of young Austrocedrus forests was verified in 9% of the forest area. Spatial patterns were studied on an area of 10,000 ha showing a high heterogeneity of the distinctive landscape configurations.Los bosques nativos en Patagonia han estado influidos por la acción del hombre desde principios del siglo pasado. Sin embargo, la disponibilidad de fotografías aéreas para efectuar análisis de cambios debidos a factores antrópicos a escala de paisaje está generalmente restringida a las últimas décadas. En consecuencia, este estudio estuvo orientado a detectar y analizar los cambios de la heterogeneidad del paisaje forestal durante los últimos treinta años en la región noroeste de Chubut, la provincia central de Patagonia en Argentina, y a estudiar la organización espacial de paisajes forestales. Para el primer objetivo, nos concentramos en una unidad de paisaje de 2.000 ha con predominancia de bosques de Austrocedrus chilensis. En 466 ha cubiertas con estos bosques, 41% de esta área fue negativamente afectado por incendios forestales, extracciones forestales seguidas de pastoreo y reemplazo de bosques nativos por plantaciones de pinos. En contraste, el crecimiento de bosques jóvenes de Austrocedrus se verificó en el 9% del área forestal. Los patrones espaciales se estudiaron en un área de 10.000 ha y mostraron una alta heterogeneidad de las configuraciones distintivas del paisaje

All-carbon multi-electrode array for real-time in vitro measurements of oxidizable neurotransmitters

We report on the ion beam fabrication of all-carbon multi electrode arrays (MEAs) based on 16 graphitic micro-channels embedded in single-crystal diamond (SCD) substrates. The fabricated SCD-MEAs are systematically employed for the in vitro simultaneous amperometric detection of the secretory activity from populations of chromaffin cells, demonstrating a new sensing approach with respect to standard techniques. The biochemical stability and biocompatibility of the SCD-based device combined with the parallel recording of multi-electrodes array allow: i) a significant time saving in data collection during drug screening and/or pharmacological tests over a large number of cells, ii) the possibility of comparing altered cell functionality among cell populations, and iii) the repeatition of acquisition runs over many cycles with a fully non-toxic and chemically robust bio-sensitive substrate.Comment: 24 pages, 5 figure

Model and Design of a Power Driver for Piezoelectric Stack Actuators

A power driver has been developed to control piezoelectric stack actuators used in automotive application. An FEM model of the actuator has been implemented starting from experimental characterization of the stack and mechanical and piezoelectric parameters. Experimental results are reported to show a correct piezoelectric actuator driving method and the possibility to obtain a sensorless positioning control

Nanodiamonds-induced effects on neuronal firing of mouse hippocampal microcircuits

Fluorescent nanodiamonds (FND) are carbon-based nanomaterials that can efficiently incorporate optically active photoluminescent centers such as the nitrogen-vacancy complex, thus making them promising candidates as optical biolabels and drug-delivery agents. FNDs exhibit bright fluorescence without photobleaching combined with high uptake rate and low cytotoxicity. Focusing on FNDs interference with neuronal function, here we examined their effect on cultured hippocampal neurons, monitoring the whole network development as well as the electrophysiological properties of single neurons. We observed that FNDs drastically decreased the frequency of inhibitory (from 1.81 Hz to 0.86 Hz) and excitatory (from 1.61 Hz to 0.68 Hz) miniature postsynaptic currents, and consistently reduced action potential (AP) firing frequency (by 36%), as measured by microelectrode arrays. On the contrary, bursts synchronization was preserved, as well as the amplitude of spontaneous inhibitory and excitatory events. Current-clamp recordings revealed that the ratio of neurons responding with AP trains of high-frequency (fast-spiking) versus neurons responding with trains of low-frequency (slow-spiking) was unaltered, suggesting that FNDs exerted a comparable action on neuronal subpopulations. At the single cell level, rapid onset of the somatic AP ("kink") was drastically reduced in FND-treated neurons, suggesting a reduced contribution of axonal and dendritic components while preserving neuronal excitability.Comment: 34 pages, 9 figure