Versatile stochastic dot product circuits based on nonvolatile memories for high performance neurocomputing and neurooptimization.

The key operation in stochastic neural networks, which have become the state-of-the-art approach for solving problems in machine learning, information theory, and statistics, is a stochastic dot-product. While there have been many demonstrations of dot-product circuits and, separately, of stochastic neurons, the efficient hardware implementation combining both functionalities is still missing. Here we report compact, fast, energy-efficient, and scalable stochastic dot-product circuits based on either passively integrated metal-oxide memristors or embedded floating-gate memories.

Controlling Magnetoresistance by Oxygen Impurities in Mq3-Based Molecular Spin Valves.

The understanding of magnetoresistance (MR) in organic spin valves (OSVs) based on molecular semiconductors is still incomplete after its demonstration more than a decade ago. Although carrier concentration may play an essential role in spin transport in these devices, direct experimental evidence of its importance is lacking. We probed the role of the charge carrier concentration by studying the interplay between MR and multilevel resistive switching in OSVs.

Spike-timing-dependent plasticity learning of coincidence detection with passively integrated memristive circuits.

Spiking neural networks, the most realistic artificial representation of biological nervous systems, are promising due to their inherent local training rules that enable low-overhead online learning, and energy-efficient information encoding. Their downside is more demanding functionality of the artificial synapses, notably including spike-timing-dependent plasticity, which makes their compact efficient hardware implementation challenging with conventional device technologies. Recent work showed that memristors are excellent candidates for artificial synapses, although reports of even simple neuromorphic systems are still very rare.

High-Performance Mixed-Signal Neurocomputing With Nanoscale Floating-Gate Memory Cell Arrays.

Potential advantages of analog- and mixed-signal nanoelectronic circuits, based on floating-gate devices with adjustable conductance, for neuromorphic computing had been realized long time ago. However, practical realizations of this approach suffered from using rudimentary floating-gate cells of relatively large area. Here, we report a prototype $28\times28$ binary-input, ten-output, three-layer neuromorphic network based on arrays of highly optimized embedded nonvolatile floating-gate cells, redesigned from a commercial 180-nm nor flash memory.

Implementation of multilayer perceptron network with highly uniform passive memristive crossbar circuits.

The progress in the field of neural computation hinges on the use of hardware more efficient than the conventional microprocessors. Recent works have shown that mixed-signal integrated memristive circuits, especially their passive (0T1R) variety, may increase the neuromorphic network performance dramatically, leaving far behind their digital counterparts. The major obstacle, however, is immature memristor technology so that only limited functionality has been reported.

Corrigendum: A multiply-add engine with monolithically integrated 3D memristor crossbar/CMOS hybrid circuit.

This corrects the article DOI: 10.1038/srep42429.

A multiply-add engine with monolithically integrated 3D memristor crossbar/CMOS hybrid circuit.

Silicon (Si) based complementary metal-oxide semiconductor (CMOS) technology has been the driving force of the information-technology revolution. However, scaling of CMOS technology as per Moore's law has reached a serious bottleneck. Among the emerging technologies memristive devices can be promising for both memory as well as computing applications.

Seed layer technique for high quality epitaxial manganite films.

We introduce an innovative approach to the simultaneous control of growth mode and magnetotransport properties of manganite thin films, based on an easy-to-implement film/substrate interface engineering. The deposition of a manganite seed layer and the optimization of the substrate temperature allows a persistent bi-dimensional epitaxy and robust ferromagnetic properties at the same time. Structural measurements confirm that in such interface-engineered films, the optimal properties are related to improved epitaxy.

Self-Adaptive Spike-Time-Dependent Plasticity of Metal-Oxide Memristors.

Metal-oxide memristors have emerged as promising candidates for hardware implementation of artificial synapses - the key components of high-performance, analog neuromorphic networks - due to their excellent scaling prospects. Since some advanced cognitive tasks require spiking neuromorphic networks, which explicitly model individual neural pulses ("spikes") in biological neural systems, it is crucial for memristive synapses to support the spike-time-dependent plasticity (STDP). A major challenge for the STDP implementation is that, in contrast to some simplistic models of the plasticity, the elementary change of a synaptic weight in an artificial hardware synapse depends not only on the pre-synaptic and post-synaptic signals, but also on the initial weight (memristor's conductance) value.

Training and operation of an integrated neuromorphic network based on metal-oxide memristors.

Despite much progress in semiconductor integrated circuit technology, the extreme complexity of the human cerebral cortex, with its approximately 10(14) synapses, makes the hardware implementation of neuromorphic networks with a comparable number of devices exceptionally challenging. To provide comparable complexity while operating much faster and with manageable power dissipation, networks based on circuits combining complementary metal-oxide-semiconductors (CMOSs) and adjustable two-terminal resistive devices (memristors) have been developed. In such circuits, the usual CMOS stack is augmented with one or several crossbar layers, with memristors at each crosspoint.

Ultrahigh vacuum and low-temperature cleaning of oxide surfaces using a low-concentration ozone beam.

We present a novel method of delivering a low-concentration (<15%) ozone beam to an ultra-high vacuum environment for the purpose of cleaning and dosing experimental samples through oxidation processing. The system described is safe, low-cost, and practical and overcomes the limitations of ozone transport in the molecular flow environment of high or ultrahigh vacuum whilst circumventing the use of pure ozone gas which is potentially highly explosive. The effectiveness of this method in removing surface contamination is demonstrated through comparison of high-temperature annealing of a simple oxide (MgO) in ozone and oxygen environments as monitored using quadrupole mass spectroscopy and Auger electron spectroscopy.

[Psychopathologic risk assessment and self-esteem in patients undergoing hypospadias surgery].

Aims: Although the long-term outcomes ofhypospadias surgery are considered important for psychosexual development, only a few attempts have been made to evaluate patient psico-pathology.

Material And Methods: 20 out 40 patients who received under sealed cover two envelopes--the first containing the assessment tools, the other empty and prepaid for the answer--joined the study. The results came from the analysis of anamnestic interview specially created in order to gather information on how to access to surgery and the degree of information that the parents had from the surgeon, from the analysis of the CBCL (Child Behavior CheckList 2001:4-16 years) and TMA (Multidimensional self-esteem Test: the Italian version of the MSCS Multidimensional Self-Concept Scale).

Surface nanostructures in manganite films.

Ultrathin manganite films are widely used as active electrodes in organic spintronic devices. In this study, a scanning tunnelling microscopy (STM) investigation with atomic resolution revealed previously unknown surface features consisting of small non-stoichiometric islands. Based upon this evidence, a new mechanism for the growth of these complex materials is proposed.

[Advantages of the anterior and mid-shaft hypospadias repair in the first year of life].

Purpose: Only a few studies have been performed on the evaluation of complications strictly related to the age at operation of hypospadias repair. The aim of our study was to evaluate the incidence of complications of surgical treatment of anterior and midshaft hypospadias in relation to the age at operation.

Materials And Methods: 108 patients from 2005 to 2011 were operated on by the same surgeon (AM) for anterior and mid-shaft hypospadias.

Tunnel conductivity switching in a single nanoparticle-based nano floating gate memory.

Nanoparticles (NPs) embedded in a conductive or insulating matrix play a key role in memristors and in flash memory devices. However, the role of proximity to the interface of isolated NPs has never been directly observed nor fully understood. Here we show that a reversible local switching in tunnel conductivity can be achieved by applying an appropriate voltage pulse using the tip of a scanning tunnelling microscope on NPs embedded in a TiO2 matrix.

[Laparoscopic treatment of UPJ obstruction in ectopic pelvic kidneys in children].

Aims: To assess the feasibility and safety of a laparoscopic approach to UPJ obstruction (UPJO) in ectopic pelvic kidneys.

Material And Methods: In a retrospective analysis we selected 14 children, aged 6 months to 17 years, 12 males, 2 females, who had been treated in our Department between January 2004 and June 2011. 9 patients presented ureteropelvic junction obstruction (in 3 cases pelvic stones coexisted) with normal/moderately reduced (> or = 25%) relative function at radionuclide scan (MAG3), 3 nonfunctioning kidneys associated or not to hypertension, 2 congenital hypo-dysplastic kidneys.

A single-device universal logic gate based on a magnetically enhanced memristor.

Memristors are one of the most promising candidates for future information and communications technology (ICT) architectures. Two experimental proofs of concept are presented based on the intermixing of spintronic and memristive effects into a single device, a magnetically enhanced memristor (MEM). By exploiting the interaction between the memristance and the giant magnetoresistance (GMR), a universal implication (IMP) logic gate based on a single MEM device is realized.

Regenerable resistive switching in silicon oxide based nanojunctions.

A nanomemristor based on SiO(2) is fabricated in situ with spatial control at the nanoscale. The proposed system exhibits peculiar properties such as the possibility to be regenerated after being stressed or damaged and the possibility to expose the metal and the oxide interfaces by removing the top electrodes.

"Spaghetti maneuver": a useful tool in pediatric laparoscopy - our experience.

Aims: The laparoscopic "Spaghetti Maneuver" consists in holding an organ by its extremity with a grasper and rolling it up around the tool to keep the organ stable and facilitate its traction within a small space. We describe our experience with the "Spaghetti Maneuver" in some minimally invasive procedures.

Materials And Methods: We successfully adopted this technique in 13 patients (5F : 8M) aged between 6 and 14 years (average age, 10) on whom we performed 7 appendectomies, 2 ureteral reimplantation and 4 cholecystectomies.

Organic spintronics.

Organic semiconductors are emerging materials in the field of spintronics. Successful achievements include their use as a tunnel barrier in magnetoresistive tunnelling devices and as a medium for spin-polarized current in transport devices. In this paper, we give an overview of the basic concepts of spin transport in organic semiconductors and present the results obtained in the field, highlighting the open questions that have to be addressed in order to improve devices performance and reproducibility.

Pneumovesicoscopic correction of primary vesicoureteral reflux (VUR) in children. Our experience.

Aim: We report our experience with pneumovesicoscopic cross-trigonal ureteral reimplantation to correct primary vesicoureteral reflux (VUR) in children.

Material And Methods: 14 children (10 girls, 4 boys, aged 4 to 12 years) with persistent VUR ≥ grade III (5 bilateral, 19 refluxing ureters) underwent pneumovesicoscopic Cohen's cross-trigonal reimplantation. Under cystoscopic control, a first midline 5-mm trocar was introduced for a 0°\30° telescope at the dome of the bladder, and 2 left and right 3- or 5-mm trocars were inserted through the anterolateral wall.

Effectiveness of botulinum-A toxin for the treatment of refractory overactive bladder in children.

Aims: We describe our experience with botulinum-A toxin (BTX-A) in children presenting idiopathic overactive bladder (OAB) refractory to anticholinergic drugs.

Material And Methods: 21 patients, aged 8-12 years, were treated over a 3-year period. BTX-A was administered at a dosage of 12.

Pneumovesicoscopic treatment of congenital bladder diverticula in children: our experience.

Aim: In this article, we report our experience with diverticulectomies of symptomatic congenital bladder diverticula in children, which was performed by utilizing pneumovesicoscopy.

Materials And Methods: Six boys, 4-8 years of age (mean, 5.6) underwent pneumovesicoscopic diverticulectomy at our institution from June 2007 to June 2008.