Novel electrical and chemical findings on SIOx-based ReRAM devices

Existing non-volatile flash memory technologies are characterised by slow access time, high power consumption and a quickly approaching scaling limit. Filamentary resistive RAM (ReRAM) is an emerging type of storage device that relies on the electrically driven change in resistance of a thin film sandwiched between two electrodes. The active region is often a binary oxide that develops a restorable conductive filament thanks to the electrically driven movement of oxygen. This technology offers potential sub-10 nm scalability, nanosecond programming with direct overwriting (unlike FLASH) and an appealing sub pJ/bit power consumption (compared to nJ/bit of FLASH). In this thesis, metal-insulator-metal ReRAM devices with a TiN/SiOx/TiN structure are used. While other binary oxides have been used in the literature, SiOx must be used in its amorphous form allowing for easier fabrication, and is an extremely well-studied material as its CMOS compatibility dates back 40 years. Using the above devices, it was possible to observe data storage performance comparable to the one of other types of ReRAM. More interestingly, it was observed that the resistance states of this family of devices may be programmed using nanosecond pulses of identical magnitude, possibly leading to simple programming circuits. Consequently, it is shown that this programming method may also be used to gradually increase or decrease the device resistance state as well as have devices enter states that relax over time. These types of behaviour mean that SiOx devices may be used in neuromorphic networks that require components whose behaviour resembles the one of the neuronal synapsis or the mammalian brain’s forgetting process. The literature reports on endurance-hindering electrode deformation phenomena during the operation of oxide-based ReRAM devices. A residual gas analyser (RGA) was used to detect that oxygen species are emitted during operation and therefore confirmed that such phenomena are caused by oxygen emission. Using SIMS (secondary ion mass spectroscopy) analysis on devices switched in atmospheres containing isotopically labelled oxygen, it was observed that, under deformed regions, it is possible to find incorporated atmospheric oxygen. Additionally, reducing atmospheric pressure had negative impact on device reliability. SiOx-based filamentary ReRAM is a strong candidate in the search for alternatives to flash memory. Moreover, these devices display behaviour that may be useful in applications trying to emulate the mammalian brain. Having observed device dependence on its atmosphere, endurance issues may now be addressed using electrodes capable of either adsorbing oxygen without bubbling or letting it go through without cracking

Advanced physical modeling of SiOx resistive random access memories

We apply a three-dimensional (3D) physical simulator, coupling self-consistently stochastic kinetic Monte Carlo descriptions of ion and electron transport, to investigate switching in silicon-rich silica (SiOx) redox-based resistive random-access memory (RRAM) devices. We explain the intrinsic nature of resistance switching of the SiOx layer, and demonstrate the impact of self-heating effects and the initial vacancy distributions on switching. We also highlight the necessity of using 3D physical modelling to predict correctly the switching behavior. The simulation framework is useful for exploring the little-known physics of SiOx RRAMs and RRAM devices in general. This proves useful in achieving efficient device and circuit designs, in terms of performance, variability and reliability

Physical activity for the prevention and treatment of metabolic disorders

Metabolic syndrome and its various features 10 (obesity, hypertension, dyslipidemia, diabetes, and nonal- 11 coholic fatty liver disease) are increasing worldwide and 12 constitute a severe risk for the sustainability of the present 13 universal Italian health care system. Lifestyle interventions 14 should be the first therapeutic strategy to prevent/treat 15 metabolic diseases, far before pharmacologic treatment. 16 The role of diet and weight loss has been fully ascertained, 17 whereas the role of physical activity is frequently over- 18 looked both by physicians and by patients. Physical activity 19 has favorable effects on all components of the metabolic 20 syndrome and on the resulting cardiovascular risk, the 21 cornerstone in the development of cardiometabolic dis- 22 eases. The quantity and the frequency of physical activity 23 necessary to produce beneficial effects has not been defined 24 as yet, but brisk walking is considered particularly appro- 25 priate, as it can be practiced by a large number of indi- 26 viduals, without any additional cost, and has a low rate of 27 injury. The effects of exercise and leisure time physical 28 activity extend from prevention to treatment of the various 29 components of the metabolic syndrome, as well as to mood 30 and quality of life. Any effort should be done to favor adherence to protocols of physical activity in the 31 community

Investigation of resistance switching in SiOx RRAM cells using a 3D multi-scale kinetic Monte Carlo simulator

We employ an advanced three-dimensional (3D) electro-thermal simulator to explore the physics and potential of oxide-based resistive random-access memory (RRAM) cells. The physical simulation model has been developed recently, and couples a kinetic Monte Carlo study of electron and ionic transport to the self-heating phenomenon while accounting carefully for the physics of vacancy generation and recombination, and trapping mechanisms. The simulation framework successfully captures resistance switching, including the electroforming, set and reset processes, by modeling the dynamics of conductive filaments in the 3D space. This work focuses on the promising yet less studied RRAM structures based on silicon-rich silica (SiOx) RRAMs. We explain the intrinsic nature of resistance switching of the SiOx layer, analyze the effect of self-heating on device performance, highlight the role of the initial vacancy distributions acting as precursors for switching, and also stress the importance of using 3D physics-based models to capture accurately the switching processes. The simulation work is backed by experimental studies. The simulator is useful for improving our understanding of the little-known physics of SiOx resistive memory devices, as well as other oxide-based RRAM systems (e.g. transition metal oxide RRAMs), offering design and optimization capabilities with regard to the reliability and variability of memory cells

Long-term weight loss maintenance for obesity: a multidisciplinary approach

The long-term weight management of obesity remains a very difficult task, associated with a high risk of failure and weight regain. However, many people report that they have successfully managed weight loss maintenance in the long term. Several factors have been associated with better weight loss maintenance in long-term observational and randomized studies. A few pertain to the behavioral area (eg, high levels of physical activity, eating a low-calorie, low-fat diet; frequent self-monitoring of weight), a few to the cognitive component (eg, reduced disinhibition, satisfaction with results achieved, confidence in being able to lose weight without professional help), and a few to personality traits (eg, low novelty seeking) and patient–therapist interaction. Trials based on the most recent protocols of lifestyle modification, with a prolonged extended treatment after the weight loss phase, have also shown promising long-term weight loss results. These data should stimulate the adoption of a lifestyle modification-based approach for the management of obesity, featuring a nonphysician lifestyle counselor (also called “lifestyle trainer” or “healthy lifestyle practitioner”) as a pivotal component of the multidisciplinary team. The obesity physicians maintain a primary role in engaging patients, in team coordination and supervision, in managing the complications associated with obesity and, in selected cases, in the decision for drug treatment or bariatric surgery, as possible more intensive, add-on interventions to lifestyle treatment

Hepatocellular carcinoma on cirrhosis complicated with tumoral thrombi extended to the right atrium: Results in three cases treated with major hepatectomy and thrombectomy under hypothermic cardiocirculatory arrest and literature review

BACKGROUND: Hepatocellular carcinoma (HCC) with the presence of tumor thrombus in hepatic veins and vena cava, until the atrium (RATT), is correlated with poor prognosis and with risk of tricuspid valve occlusion, congestive heart failure, and pulmonary embolism. METHODS: Three patients with HCC on cirrhotic liver with RATT were studied. Operative technique, pre-operative and post-operative liver function tests, blood loss and transfusions, post-operative morbidity and mortality, and the overall survival and the disease free survival were analyzed. RESULTS: Mean operative time was 336 ± 66 min. Intra-operative blood loss was 926.6 ± 325.9 ml. No major complications occurred. The times of hospital stay were 10, 21, and 19 days, respectively. The survival times were 90, 161, and 40 days, and the disease-free survival times were 30, 141, and 30 days, respectively. CONCLUSIONS: The complete removal of HCC with RATT may be achieved with cardiopulmonary by-pass (CPB) and total hepatic vascular exclusion (THVE). Adding the hypothermic cardiocirculatory arrest (HCCA) to the use of CPB allowed us to have minimal blood loss and hemostasis of the resectional plane. So the use of CPB and HCCA should be considered a good therapeutic alternative to the normothermic CPB with THVE

A standard ballroom and Latin dance program to improve fitness and adherence to physical activity in individuals with type 2 diabetes and in obesity

Objective: To test the effectiveness of a dance program to improve fitness and adherence to physical activity in subjects with type 2 diabetes and obesity.Research Design and Methods: Following a motivational interviewing session, 100 subjects with diabetes and/or obesity were enrolled either in a dance program (DP, n = 42) or in a self-selected physical activity program (SSP, n = 58), according to their preferences. Outcome measures were reduced BMI/waist circumference, improved metabolic control in type 2 diabetes ( 120.3% reduction of HbA1c) and improved fitness (activity expenditure >10 MET-hour/week; 10% increase in 6-min walk test (6MWT)). Target achievement was tested at 3 and 6 months, after adjustment for baseline data (propensity score). Results: Attrition was lower in DP. Both programs significantly decreased body weight (on average, 122.6 kg; P < 0.001) and waist circumference (DP, 123.2 cm; SSP, 122.2; P < 0.01) at 3 months, and the results were maintained at 6 months. In DP, the activity-related energy expenditure averaged 13.5 \ub1 1.8 MET-hour/week in the first three months and 14.1 \ub1 3.0 in the second three-month period. In SSP, activity energy expenditure was higher but highly variable in the first three-month period (16.5 \ub1 13.9 MET-hour/week), and decreased in the following three months (14.2 \ub1 12.3; P vs. first period < 0.001). At three months, no differences in target achievement were observed between groups. After six months the odds to attain the MET, 6MWT and A1c targets were all significantly associated with DP. Conclusion: Dance may be an effective strategy to implement physical activity in motivated subjects with type 2 diabetes or obesity (Clinical trial reg. no. NCT02021890, clinicaltrials.gov)

Radiation therapy during the coronavirus disease 2019 (covid-19) pandemic in Italy: a view of the nation&apos;s young oncologists

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Antiplatelet therapy and the outcome of subjects with intracranial injury: the Italian SIMEU study

Introduction Pre-injury antithrombotic therapy might influence the outcome of subjects with head injuries and positive computed tomography (CT) scans. We aimed to determine the potential risk of pre-injury antiplatelet drug use on short- and long-term outcome of head injured subjects admitted to emergency departments (EDs) in Italy for extended observation. Methods A total of 1,558 adult subjects with mild, moderate and severe head injury admitted to Italian EDs were studied. In multivariable logistic regression analyses, the short-term outcome was assessed by an evaluation of head CT scan at 6 to 24 hours after trauma and the long-term outcome by the Glasgow outcome scale (GOS) at six months. Results Head CT scan comparisons showed that 201 subjects (12.9%) worsened. The risk of worsening was increased two fold by the use of antiplatelet drugs (106, 19.7% treated versus 95, 9.3% untreated; relative risk (RR) 2.09, 95% CI 1.63 to 2.71). The risk was particularly high in subjects on clopidogrel (RR 5.76, 95% CI 3.88 to 8.54), independent of the association with aspirin. By logistic regression, 5 of 14 items were independently associated with worsening (Glasgow coma scale (GCS), Marshall category, antiplatelet therapy, intraventricular hemorrhage, number of lesions). After six months, only 4 of 14 items were predictors of unfavorable outcome (GOS 1 to 3) (GCS score, Marshall category, age in decades, intracerebral hemorrhage/contusion). The risk increased by 50% in the group treated with antiplatelet therapy (RR 1.58, 95% CI 1.28 to 1.95; P < 0.001). Conclusions Antithrombotic therapy (in particular clopidogrel) is a risk factor for both short-term and long-term unfavorable outcome in subjects with head injury, increasing the risk of progression and death, permanent vegetative state and severe disability