On the Interpretation of Hysteresis Loop for Electronic and Ionic Currents in Organic Memristive Devices

Being promising elements for neuromorphic computation, memristive devices have been often described as crucial elements for mimicking important synapse properties, such as memory and learning. Among them, organic memristive devices (OMDs) can claim low-cost fabrication processes and the easy tunability of their electrical properties. Up to now, the major bottleneck for their larger uses in neuromorphic computation is low rate of the resistance switching and stability. Herein, a new approach is reported, based on the use of a liquid electrolyte, leading to the manufacturing of OMD with higher stability and faster resistive switching

Analysis of the Compliance Properties of an Industrial Robot with the Mozzi Axis Approach

In robotic processes, the compliance of the robot arm plays a very important role. In some conditions, for example, in robotic assembly, robot arm compliance can compensate for small position and orientation errors of the end-effector. In other processes, like machining, robot compliance may generate chatter vibrations with an impairment in the quality of the machined surface. In industrial robots, the compliance of the end-effector is chiefly due to joint compliances. In this paper, joint compliances of a serial six-joint industrial robot are identified with a novel modal method making use of specific modes of vibration dominated by the compliance of only one joint. Then, in order to represent the effect of the identified compliances on robot performance in an intuitive and geometric way, a novel kinematic method based on the concept of \u201cMozzi axis\u201d of the end-effector is presented and discusse

A Tactile Sensor Device Exploiting the Tunable Sensitivity of Copper-PDMS Piezoresistive Composite

Abstract A low cost and highly mechanically flexible 8x8 pressure matrix sensor with dedicated electronics has been fabricated with an innovative metal-elastomer composite material. Under the action of a compressive stress the material exhibits a giant piezoresistive effect varying its electrical resistance of several orders of magnitude. This phenomenon can be tuned by changing the material composition parameters, directly modifying the sensitivity of the sensor. The micro casting fabrication technique, used for the preparation of self standing sheet of functional material, gives the possibility of easily fabricating complex-shaped structure suitable for integration on robot surface for tactile sensing. The sensor has been tested with a customized electronic circuit after an exhaustive characterization of the functional properties of the material

The Role of the Internal Capacitance in Organic Memristive Device for Neuromorphic and Sensing Applications

Organic electronics has recently emerged as a promising candidate for the emulation of brain-like functionalities, especially at the device level. Among the proposed technologies, memristive devices have gained an increasing attention due to their non-volatile behavior which makes them suitable for the implementation of artificial neuronal networks. However, most of them have an energy-costly switching mechanism which limits the approach of brain like energy efficiency. Different from them, organic memristive devices (OMDs) have a narrow switching window and implement neuromorphic characteristics at voltages <= 1 V. Despite OMDs potentialities in bioinspired electronics, guidelines for the design of devices and materials are still missing. Here it is shown that the device capacitance represents a significant degree of freedom for targeting devices applications. It is also shown that a single OMD emulates activity dependent synaptic functions and neuronal temporal and spatial summation, taking advantage of its three-terminals configuration. Interestingly, despite the neuromorphic applications, OMDs can also sense and amplify incoming signals on the basis of their capacitive and/or resistive values. This spectrum of applications, ranging from volatile to non-volatile characteristics and from neuromorphic computing to bio signals sensing, sets the stage for the realization of integrated circuits for adaptive sensing

Null-Space Minimization of Center of Gravity Displacementof a Redundant Aerial Manipulator

Displacements of the base during trajectory tracking are a common issue in the control of aerial manipulators. These are caused by reaction torques transferred to the base due to the manipulator motion and, in particular, to the motion of its center of gravity. We present a novel approach to reduce base displacements of a kinematically redundant aerial manipulator by using null-space projection in the inverse kinematic control. A secondary objective function minimizes the horizontal displacement of the manipulator center of gravity. We test this algorithm on different trajectories for both three and four degrees of freedom (DOF) manipulators in a simulation environment. The results comparing our algorithm with inverse kinematic control without the null-space projection show up to an 80% reduction in the end-effector position error and an average of about 56% reduction in maximum base displacement. The simulation implementation also runs faster than in real-time in our code implementation. We provide a workspace analysis based on multiple stopping criteria such as excessive base displacement, joint velocities and end-effector position error for the 3 and 4 DOF manipulators. As expected, the 4 DOF manipulator has a larger workspace

Identification of D179H, a novel missense GJB2 mutation in a Western Sicily family

The main purpose of this study was to describe a novel missense mutation (p.D179H) found in a Western Sicily family and to examine the genetic and audiologic profiles of all family members by performing a GJB2 and GJB6 mutations analysis and a complete audiologic assessment. The proband was a 3-month-old infant with a congenital profound sensorineural hearing loss; direct sequencing of the GJB2 revealed the presence of a c.35delG mutation in the heterozygous state and a heterozygous G[C transition at nucleotide 535 in trans; this novel mutation, called p.D179H, resulted in an aspartic acid to histidine change at codon 179. It was also evidenced in the heterozygous state in two members of this family, both with normal hearing. No GJB6 mutations were evidenced in all subjects studied. Considering the genotypic and phenotypic analysis of all family members, we suggest, differently from the p.D179 N mutation previously reported, a recessive mode of inheritance. Functional studies on p.D179H have to be performed to confirm our hypothesis

Essential of audiology: screening and postscreening

Newborn hearing screening is a type of screening test for the early detection of hearing loss. It can recognize with good accuracy newborns affected by hearing impairment allowing an early diagnosis and intervention and avoiding cognitive and linguistic deficits [1-6]. The incidence of bilateral sensorineural hearing loss (SNHL) in Sicily is 2.35 cases per 1000 newborns; this value increases to 2.95 if we consider also unilateral SNHL [2,3] and to 10 cases per 1000 births among infants at risk [7-9]. A correct newborn hearing screening programme is based on different protocols depending on the presence/ absence of audiologic risk factor

Oxidative stress neuroinflammation and cellular stress response in sensorineural hearing loss: novel nutritional therapeutical approaches

This study is intended to validate the hypothesis that changes in the redox state of glutathione, the major endogenous antioxidant, associated with the abnormal expression and activity of cytoprotective vitagenes, which in normal conditions are expressed only at low level may represent a critical factor, involved in the physiopathological changes associated to degenerative damage occurring in cochlear diseases. Moreover modulation of stress responsive vitagenes by nutritional antioxidants can be an effective therapeutic strategy to minimize consequences of oxidative stress associated to the pathogenesis and course of sensorineural hearing loss. One therapeutic approach can be antioxidant substances, as cisteina and superoxide dismutase supplementation to burst vitagenes and confer neuroprotection. The damage caused in the inner ear by oxidative stress can induce apoptosis and necrosis of both the hair cells as neurons of the spiral ganglion. Reactive oxygen species (ROS) and free radicals are formed not only as by-products of various metabolic pathways but also for exposure to ototoxic substances such as aminoglycosides and cisplatin, for hypoxia/ischemia and to exposure to noise. Although the mechanism of production of ROS within the cochlea has not yet been precisely identified, it is conceivable that mitochondrial dysfunction and consequent burst in oxidative stress are major causative factors. Consistent with this notion, it is known that the base of the cochlea is more vulnerable to oxidative damage resulted from exposure to ototoxic substances than the apical portions. The difference in survival between the basal outer hair cells and the apical ones appear to be due to a significantly lower level of glutathione in the basal outer hair cells than the apical, a phenomenon that makes it easier basal cells vulnerable to damage from free radicals. © Mattioli 188

Post laryngectomy speech rehabilitation outcome in elderly patients

The aim of our work has been to evaluate the different options of tracheoesophageal voice rehabilitation in over 70-year-old patients, who had undergone laryngectomy, assessing advantages and drawbacks of this method of vocal recovery. A retrospective study has been carried out. This has included 40 subjects, all aged more than 70 years old, who have been referred to tracheoesophageal voice rehabilitation. It has been realized a phonatory fistula between trachea and esophagus with prosthesis positioning by means of a primary puncture in 18 cases and it has been realized a secondary puncture in 22 cases. The results gathered in these patients were compared with data obtained from a group made of 39 patients, less than 70 years of age that therefore represented our control group. In primary tracheoesophageal puncture (TEP), the short-term success was 67 %, while in the 22 cases who underwent secondary TEP, the short-term success was 64 %. After 2 years from TEP, the long-term success was 82.5 %. In the control group, the short-term success was 65 % in primary TEP and 73 % in secondary TEP. After 2 years from TEP, the long-term success was 77 %. The evaluation of the results has shown the absence of a statistically significant difference both as regards complications incidence, during and after surgery (p > 0.9) and as regards overall success ratio of prosthesis implants between the two groups (p > 0.7). The possibilities of tracheoesophageal recovery of elderly patients do not show dissimilarities in comparison with the results in younger subjects