Parameter extraction techniques for the analysis and modeling of resistive memories

A revision of the different numerical techniques employed to extract resistive switching (RS) and modeling parameters is presented. The set and reset voltages, commonly used for variability estimation, are calculated for different resistive memory technologies. The methodologies to extract the series resistance and the parameters linked to the charge-flux memristive modeling approach are also described. It is found that the obtained cycle-to-cycle (C2C) variability depends on the numerical technique used. This result is important, and it implies that when analyzing C2C variability, the extraction technique should be described to perform fair comparisons between different resistive memory technologies. In addition to the use of extensive experimental data for different types of resistive memories, we have also included kinetic Monte Carlo (kMC) simulations to study the formation and rupture events of the percolation paths that constitute the conductive filaments (CF) that allow resistive switching operation in filamentary unipolar and bipolar devices.Consejería de Conocimiento, Investigaci ́on y Universidad, Junta de Andalucía (Spain) and the FEDER program for the projects A.TIC.117.UGR18, B-TIC-624-UGR20 and IE2017-5414Ramón y Cajal grant No. RYC2020-030150-IFunding for open access charge: Universidad de Granada/CBU

Contenido y distribución de Mn en una secuencia de suelos. Relaciones con el Fe

8 páginas, 1 tabla y un dendogramaSe estudian los contenidos en Mn, presentes en varias formas, en algunas muestras de una secuencia de suelos. Esta secuencia incluye suelos de tipo Regosol, Cambisol, Luvisol y Planosol. Las cantidades totales de Mn están por debajo de la media mundial. Se detecta que las formas extraídas por métodos selectivos son algo más elevadas en la fracción arcilla que en la fracción < 2m.m Se puede indicar que hay cierta asociación Mn-Fe en los suelos estudiados.Peer reviewe

Effect of Coronavirus Disease 2019 in Pulmonary Circulation. The Particular Scenario of Precapillary Pulmonary Hypertension.

The Coronavirus Disease of 2019 (COVID-19) has supposed a global health emergency affecting millions of people, with particular severity in the elderly and patients with previous comorbidities, especially those with cardiovascular disease. Patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) could represent an especially vulnerable population because of the high mortality rates reported for respiratory infections. However, the number of COVID-19 cases reported among PAH and CTEPH patients is surprisingly low. Furthermore, the clinical picture that has been described in these patients is far from the severity that experts would expect. Endothelial dysfunction is a common feature between patients with PAH/CTEPH and COVID-19, leading to ventilation/perfusion mismatch, vasoconstriction, thrombosis and inflammation. In this picture, the angiotensin-converting enzyme 2 plays an essential role, being directly involved in the pathophysiology of both clinical entities. Some of these common characteristics could explain the good adaptation of PAH and CTEPH patients to COVID-19, who could also have obtained a benefit from the disease's specific treatments (anticoagulant and pulmonary vasodilators), probably due to its protective effect on the endothelium. Additionally, these common features could also lead to PAH/CTEPH as a potential sequelae of COVID-19. Throughout this comprehensive review, we describe the similarities and differences between both conditions and the possible pathophysiological and therapeutic-based mechanisms leading to the low incidence and severity of COVID-19 reported in PAH/CTEPH patients to date. Nevertheless, international registries should look carefully into this population for better understanding and management.J.N. is recipient of a predoctoral grant (Jordi Soler Soler) through CIBERCV. E.O. is a recipient of funds from “Programa de Atracción de Talento” (2017-T1/BMD-5185) of Comunidad de Madrid. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (SEV-2015-0505). This work was supported by the Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (COV20/00181) and co-financed by the European Development Regional Fund “A way to achieve Europe”.S

Variability estimation in resistive switching devices, a numerical and kinetic Monte Carlo perspective

Acknowledgments The authors thank the support of the Spanish Ministry of Science, Innovation and Universities and the FEDER program through projects TEC2017-84321-C4-1-R, TEC2017-84321-C4-3-R, and projects A.TIC.117.UGR18, IE2017-5414 and B.TIC.624.UGR20 funded by the Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía (Spain) and the FEDER program. Funding for open access charge: Universidad de Granada/CBUAWe have analyzed variability in resistive memories (Resistive Random Access Memories, RRAMs) making use of advanced numerical techniques to process experimental measurements and simulations based on the kinetic Monte Carlo technique. The devices employed in the study were fabricated using the TiN/Ti/HfO2/W stack. The switching parameters were obtained making use of new developed extraction methods. The appropriateness of the advanced parameter extraction methodologies has been checked by comparison to kinetic Monte Carlo simulations; in particular, the reset and set events have been studied and detected. The data obtained were employed to shed light on the resistive switching operation and the cycle-to-cycle variability. It has been shown that variability depends on the numerical technique employed to obtain the set and reset voltages, therefore, this issue must be taken into consideration in RS characterization and modeling studies. The proposed techniques are complementary and depending on the technology and the curves shape the features of a particular method could make it to be the most appropriate.Spanish Ministry of Science, Innovation and Universities and the FEDER program through projects TEC2017-84321-C4-1-R, TEC2017-84321-C4-3-RConsejería de Conocimiento, Investigación y Universidad, Junta de Andalucía (Spain) and the FEDER program, projects A.TIC.117.UGR18, IE2017-5414 and B.TIC.624.UGR20Funding for open access charge: Universidad de Granada/CBU

Heart transplantation using allografts from older donors: multicenter study results

33rd Annual Meeting and Scientific Session of the International Society for Heart and Lung Transplantation, April 24–27, 2013, Montreal, Canada.[Abstract] Background. The lengthy waiting time for heart transplantation is associated with high mortality. To increase the number of donors, new strategies have emerged, including the use of hearts from donors ≥50 years old. However, this practice remains controversial. The aim of this study was to evaluate outcomes of patients receiving heart transplants from older donors. Methods. We retrospectively analyzed 2,102 consecutive heart transplants in 8 Spanish hospitals from 1998 to 2010. Acute and overall mortality were compared in patients with grafts from donors ≥50 years old versus grafts from younger donors. Results. There were 1,758 (84%) transplanted grafts from donors < 50 years old (Group I) and 344 (16%) from donors ≥50 years old (Group II). Group I had more male donors than Group II (71% vs 57%, p = 0.0001). The incidence of cardiovascular risk factors was higher in older donors. There were no differences in acute mortality or acute rejection episodes between the 2 groups. Global mortality was higher in Group II (rate ratio, 1.40; 95% confidence interval, 1.18–1.67; p = 0.001) than in Group I. After adjusting for donor cause of death, donor smoking history, recipient age, induction therapy, and cyclosporine therapy, the differences lost significance. Group II had a higher incidence of coronary allograft vasculopathy at 5 years (rate ratio, 1.67; 95% confidence interval, 1.22–2.27; p = 0.001). Conclusions. There were no differences in acute and overall mortality after adjusting for confounding factors. However, there was a midterm increased risk of coronary allograft vasculopathy with the use of older donors. Careful selection of recipients and close monitoring of coronary allograft vasculopathy are warranted in these patients.Instituto de Salud Carlos III; RD12/0042/00

Registro Español de Trasplante Cardiaco. XXVI Informe Oficial de la Sección de Insuficiencia Cardiaca y Trasplante Cardiaco de la Sociedad Española de Cardiología (1984-2014)

[Resumen] Introducción y objetivos. Se presentan las características y resultados del trasplante cardiaco en España desde que empezó su actividad en mayo de 1984. Métodos. Se realiza un análisis descriptivo de las características de los receptores, los donantes, el procedimiento quirúrgico y los resultados de los trasplantes cardiacos realizados en España hasta el 31 de diciembre de 2014. Resultados. Durante 2014 se han realizado 266 procedimientos, con lo que la serie histórica consta de 7.289 trasplantes. El análisis temporal confirma un empeoramiento significativo del perfil clínico de los receptores (mayor porcentaje de pacientes añosos, con insuficiencia renal grave, diabetes insulinodependiente, cirugía cardiaca previa y ventilación mecánica), de los donantes (mayor porcentaje de donantes añosos y con mayor discordancia de peso) y del procedimiento (mayor porcentaje de trasplante urgente, que en 2014 alcanza el 41,4%, y con tiempo de isquemia > 240 min). El uso de dispositivos de asistencia mecánica ha disminuido respecto a 2013, y en 2014 supone el 18,8% del total de pacientes. La supervivencia a 1, 5, 10 y 15 años es del 76, el 65, el 52 y el 38% respectivamente, y permanece estable desde 1995. Conclusiones. La actividad de trasplante cardiaco en España permanece estable en los últimos años, con alrededor de 250 procedimientos al año. A pesar del claro empeoramiento de las características de donantes, receptores y tiempos quirúrgicos, se mantienen unos resultados en mortalidad comparables a los del entorno y se confirma un uso creciente de los dispositivos de asistencia circulatoria antes del trasplante

Non-Invasive Assessment of Pulmonary Vasculopathy

Right heart catheterization remains necessary for the diagnosis of pulmonary hypertension and, therefore, for the prognostic evaluation of patients with chronic heart failure. The non-invaSive Assessment of Pulmonary vasculoPathy in Heart failure (SAPPHIRE) study was designed to assess the feasibility and prognostic relevance of a non-invasive evaluation of the pulmonary artery vasculature in patients with heart failure and pulmonary hypertension. Patients will undergo a right heart catheterization, cardiac resonance imaging, and a pulmonary function test in order to identify structural and functional parameters allowing the identification of combined pre- and postcapillary pulmonary hypertension, and correlate these findings with the hemodynamic dataThis research was funded by European Regional Development Fund and the Carlos III Research Institute through a grant of the Health Strategy Action (PI17/01569).S

Malignancy after heart transplantation: incidence, prognosis and risk factors

[Abstract] The Spanish Post-Heart-Transplant Tumour Registry comprises data on neoplasia following heart transplantation (HT) for all Spanish HT patients (1984–2003). This retrospective analysis of 3393 patients investigated the incidence and prognosis of neoplasia, and the influence of antiviral prophylaxis. About 50% of post-HT neoplasias were cutaneous, and 10% lymphomas. The cumulative incidence of skin cancers and other nonlymphoma cancers increased with age at HT and with time post-HT (from respectively 5.2 and 8.9 per 1000 person-years in the first year to 14.8 and 12.6 after 10 years), and was greater among men than women. None of these trends held for lymphomas. Induction therapy other than with IL2R-blockers generally increased the risk of neoplasia except when acyclovir was administered prophylactically during the first 3 months post-HT; prophylactic acyclovir halved the risk of lymphoma, regardless of other therapies. Institution of MMF during the first 3 months post-HT reduced the incidence of skin cancer independently of the effects of sex, age group, pre-HT smoking, use of tacrolimus in the first 3 months, induction treatment and antiviral treatment. Five-year survival rates after first tumor diagnosis were 74% for skin cancer, 20% for lymphoma and 32% for other tumors

Registro Español de Trasplante Cardiaco: XXXI Informe Oficial de la Asociación de Insuficiencia Cardiaca de la Sociedad Española de Cardiología

[Abstract] Introduction and objectives. The present report describes the clinical characteristics and outcomes of heart transplants in Spain and updates the data to 2019. Methods. We describe the clinical characteristics and outcomes of heart transplants performed in Spain in 2019, as well as trends in this procedure from 2010 to 2018. Results. In 2019, 300 transplants were performed (8794 since 1984; 2745 between 2010 and 2019). Compared with previous years, the most notable findings were the decreasing rate of urgent transplants (38%), and the consolidation of the type of circulatory support prior to transplant, with an almost complete disappearance of counterpulsation balloon (0.7%), stabilization in the use of extracorporeal membrane oxygenation (9.6%), and an increase in the use of ventricular assist devices (29.0%). Survival from 2016 to 2018 was similar to that from 2013 to 2015 (P=.34). Survival in both these periods was better than that from 2010 to 2012 (P=.002 and P=.01, respectively). Conclusions. Heart transplant activity has remained stable during the last few years, as have outcomes (in terms of survival). There has been a trend to a lower rate of urgent transplants and to a higher use of ventricular assist devices prior to transplant.[Resumen] Introducción y objetivos. Se presentan las características clínicas y los resultados de los trasplantes cardiacos realizados en España con la actualización correspondiente a 2019. Métodos. Se describen las características clínicas y los resultados de los trasplantes cardiacos realizados en 2019, así como las tendencias de estos en el periodo 2010-2018. Resultados. En 2019 se realizaron 300 trasplantes (8.794 desde 1984; 2.745 entre 2010 y 2019). Respecto a años previos, los cambios más llamativos son el descenso hasta el 38% de los trasplantes realizados en código urgente, y la consolidación en el cambio de asistencia circulatoria pretrasplante, con la práctica desaparición del balón de contrapulsación (0,7%), la estabilización del uso del oxigenador extracorpóreo de membrana (9,6%) y el aumento de los dispositivos de asistencia ventricular (29%). La supervivencia en el trienio 2016-2018 es similar a la del trienio 2013-2015 (p=0,34), y ambas mejores que la del trienio 2010-2012 (p=0,002 y p=0,01 respectivamente). Conclusiones. Se mantienen estables tanto la actividad del trasplante cardiaco en España como los resultados en supervivencia en los últimos 2 trienios. Hay una tendencia a realizar menos trasplantes urgentes, la mayoría con dispositivos de asistencia ventricular

Prognostic value of discharge heart rate in acute heart failure patients: more relevant in atrial fibrillation?

[Abstract] Aims. The prognostic impact of heart rate (HR) in acute heart failure (AHF) patients is not well known especially in atrial fibrillation (AF) patients. The aim of the study was to evaluate the impact of admission HR, discharge HR, HR difference (admission-discharge) in AHF patients with sinus rhythm (SR) or AF on long- term outcomes. Methods. We included 1398 patients consecutively admitted with AHF between October 2013 and December 2014 from a national multicentre, prospective registry. Logistic regression models were used to estimate the association between admission HR, discharge HR and HR difference and one- year all-cause mortality and HF readmission. Results. The mean age of the study population was 72 ± 12 years. Of these, 594 (42.4%) were female, 655 (77.8%) were hypertensive and 655 (46.8%) had diabetes. Among all included patients, 745 (53.2%) had sinus rhythm and 653 (46.7%) had atrial fibrillation. Only discharge HR was associated with one year all-cause mortality (Relative risk (RR) = 1.182, confidence interval (CI) 95% 1.024–1.366, p = 0.022) in SR. In AF patients discharge HR was associated with one year all cause mortality (RR = 1.276, CI 95% 1.115–1.459, p ≤ 0.001). We did not observe a prognostic effect of admission HR or HRD on long-term outcomes in both groups. This relationship is not dependent on left ventricular ejection fraction. Conclusions. In AHF patients lower discharge HR, neither the admission nor the difference, is associated with better long-term outcomes especially in AF patients