Improved Synaptic Device Properties of HfAlOx Dielectric on Highly Doped Silicon Substrate by Partial Reset Process

This work demonstrates the synaptic properties of the alloy-type resistive random-access memory (RRAM). We fabricated the HfAlOx-based RRAM for a synaptic device in a neuromorphic system. The deposition of the HfAlOx film on the silicon substrate was verified by X-ray photoelectron spectroscopy (XPS) analysis. It was found that both abrupt and gradual resistive switching could be implemented, depending on the reset stop voltage. In the reset process, the current gradually decreased at weak voltage, and at strong voltage, it tended to decrease rapidly by Joule heating. The type of switching determined by the first reset process was subsequently demonstrated to be stable switching by successive set and reset processes. A gradual switching type has a much smaller on/off window than abrupt switching. In addition, retention maintained stability up to 2000 s in both switching cases. Next, the multiple current states were tested in the gradual switching case by identical pulses. Finally, we demonstrated the potentiation and depression of the Cu/HfAlOx/Si device as a synapse in an artificial neural network and confirmed that gradual resistive switching was suitable for artificial synapses, using neuromorphic system simulation.

P682Radiotherapy-induced malfunction in cancer patients with cardiac implantable electronic devices

Background The number of patients with cardiac implantable electronic devices (CIED) requiring a radiation therapy (RT) for cancer treatment is increasing over time. Nevertheless, the rate and predictors of CIED malfunctions are still controversial. Purpose The aim of our study is to estimate the prevalence and possible predictors of RT-related CIED malfunctions and to describe malfunction characteristics. Methods We retrospectively reviewed medical records of all pacemaker (PM)/implantable cardioverter defibrillator (ICD) patients who underwent RT at our centre between January 2004 and July 2018. We included data from the CIED interrogation performed before the RT course to the first interrogation after the end of the RT course. As a safety measure, during RT a magnet was applied to every ICD and, in all PM-dependent patients, the device was temporarily reprogrammed in V00. Device relocation from the RT field was performed in 2/150 (1.3%) RT courses. Results One hundred twenty-seven patients were included, who underwent 150 separate RT courses. Eighty one percent of patients had a PM, while 19% had an ICD. Of note 17.4% of patients were PM-dependent. Neutron producing RT was used in 37/139 (26.6%) patients, whereas marginal neutron producing and non-neutron producing RT was used in 9/139 (6.4%) and 93/139 (67%) patients respectively. The cumulative dose (Dmax) delivered to the CIED exceeded 5Gy only in 2/132 (1.5%) cases. Three device-related malfunctions were found (2%). None of them were life-threatening or lead to a clinical event. All dysfunctions were resolved by reprogramming the device and did not require CIED substitution or leads extraction. Details of dysfunctions included: 1) a partial reset of an ICD, leading to self-reprogramming in safety mode, 2) full reset of a PM, which required the re-initialisation of the device and 3) programming change of the magnetic PM frequency to 30bpm (instead of 90 bpm). In all cases the Dmax delivered to the CIED was <1Gy. A neutron producing RT was used in the first two cases, whereas a non-neutron producing RT was used in the last case. Conclusions In accordance with the current literature, our results show that RT in patients with CIED is substantially safe. Malfunctions are uncommon and do not result in clinical events, but can develop even if the Dmax delivered to the CIED is <1 Gy. Device interrogation on a regular basis is advisable to promptly recognise CIED malfunctions.

Pitch scaling and the internal structuring of the Intonation Phrase in French

Within the autosegmental-metrical approach to French intonation, the existence of an intermediate phrase or ip is controversial. Our study provides strong evidence for its existence, by uncovering systematic pitch-scaling effects within this constituent. We first show that the presence of an ip break is responsible for blocking recursive downstep of subsequent AP-final LH* rises in declarative utterances, causing the return of the final H target to the pitch level set by the first accentual peak of the phrase (i.e. complete reset). Additional evidence for the internal structuring of the Intonation Phrase is also provided by partial reset on the postboundary H target as well as by preboundary lengthening on the last syllable of the ip. The pitch-scaling effects are claimed to result from control over the reference pitch level for the entire ip, which can alternatively be modelled through secondary association of the last pitch accent of the domain.