256 research outputs found

    Chemistry below graphene: Decoupling epitaxial graphene from metals by potential-controlled electrochemical oxidation

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    While high-quality defect-free epitaxial graphene can be efficiently grown on metal substrates, strong interaction with the supporting metal quenches its outstanding properties. Thus, protocols to transfer graphene to insulating substrates are obligatory, and these often severely impair graphene properties by the introduction of structural or chemical defects. Here we describe a simple and easily scalable general methodology to structurally and electronically decouple epitaxial graphene from Pt(111) and Ir(111) metal surfaces. A multi-technique characterization combined with ab-initio calculations was employed to fully explain the different steps involved in the process. It was shown that, after a controlled electrochemical oxidation process, a single-atom thick metal-hydroxide layer intercalates below graphene, decoupling it from the metal substrate. This decoupling process occurs without disrupting the morphology and electronic properties of graphene. The results suggest that suitably optimized electrochemical treatments may provide effective alternatives to current transfer protocols for graphene and other 2D materials on diverse metal surfacesWe acknowledge funding from the Spanish MINECO (Grants MAT2014-54231-C4-1-P, MAT2014-54231-C4-4-P, MAT2013- 47898-C2-2-R and MAT2017-85089-C2-1-R), the EU via the ERCSynergy Program (Grant ERC-2013-SYG-610256 NANOCOSMOS), the innovation program under grant agreement No. 696656 (GrapheneCore1- Graphene-based disruptive technologies), the Comunidad Aut_onoma de Madrid (CAM) MAD2D-CM Program (S2013/ MIT-3007) and computing resources from CTI-CSIC. GOI acknowledges financial support from FCT, Ministry of Science and Technology, Portugal (Grant No. PTDC/CTM-NAN/121108/2010 and IF/ 01054/2015). EL acknowledges funding from Spanish “Consolider” project CSD2010-00024. JIM acknowledges the financial support by the “Ramón y Cajal” Program of MINECO (Grant RYC-2015-17730) and NANOCOSMO

    Pathophysiology Underlying the Bimodal Edema Phenomenon After Myocardial Ischemia/Reperfusion.

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    BACKGROUND Post-ischemia/reperfusion (I/R) myocardial edema was recently shown to follow a consistent bimodal pattern: an initial wave of edema appears on reperfusion and dissipates at 24 h, followed by a deferred wave that initiates days after infarction, peaking at 1 week. OBJECTIVES This study examined the pathophysiology underlying this post-I/R bimodal edematous reaction. METHODS Forty instrumented pigs were assigned to different myocardial infarction protocols. Edematous reaction was evaluated by water content quantification, serial cardiac magnetic resonance T2-mapping, and histology/immunohistochemistry. The association of reperfusion with the initial wave of edema was evaluated in pigs undergoing 40-min/80-min I/R and compared with pigs undergoing 120-min ischemia with no reperfusion. The role of tissue healing in the deferred wave of edema was evaluated by comparing pigs undergoing standard 40-min/7-day I/R with animals subjected to infarction without reperfusion (chronic 7-day coronary occlusion) or receiving post-I/R high-dose steroid therapy. RESULTS Characterization of post-I/R tissue changes revealed maximal interstitial edema early on reperfusion in the ischemic myocardium, with maximal content of neutrophils, macrophages, and collagen at 24 h, day 4, and day 7 post-I/R, respectively. Reperfused pigs had significantly higher myocardial water content at 120 min and T2 relaxation times on 120 min cardiac magnetic resonance than nonreperfused animals. Permanent coronary occlusion or high-dose steroid therapy significantly reduced myocardial water content on day 7 post-infarction. The dynamics of T2 relaxation times during the first post-infarction week were altered significantly in nonreperfused pigs compared with pigs undergoing regular I/R. CONCLUSIONS The 2 waves of the post-I/R edematous reaction are related to different pathophysiological phenomena. Although the first wave is secondary to reperfusion, the second wave occurs mainly because of tissue healing processes.S

    On-surface self-organization of a robust metal-organic cluster based on copper(i) with chloride and organosulphur ligands

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    Direct sublimation of a Cu4Cl4 metal-organic cluster on Cu(110) under ultra-high vacuum allows the formation of ultra-large well-organized metal-organic supramolecular wires. Our results show that the large monomers assemble with each other by π-π interactions connecting dipyrimidine units and are stabilized by the surfaceWe thank Spanish MINECO (Grants: MAT2013-46753-C2-1-P, MAT2013-47878-C2-1-R and MAT2011-26534) for financial support. JIM acknowledges a CSIC-JaeDoc fellowship, cofunded by ES

    Significado pronóstico y evolución a largo plazo de la frecuencia cardiaca en los pacientes con trasplante cardiaco

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    [Abstract] Introduction and objectives. The aim of the present study was to examine the prognostic significance of heart rate and its trend in heart transplantation. Methods. This observational study enrolled 170 patients who received a bicaval heart transplant between 1995 and 2005; all were in sinus rhythm. The resting heart rate was determined via electrocardiography at the end of the first posttransplant year and annually until the tenth year. Cox analysis was used to evaluate the incidence of adverse events with a mean (standard deviation) follow-up of 8.9 (3.1) years. The primary study end point was the composite outcome of death or graft dysfunction. Results. The resting heart rate at the end of the first posttransplant year was an independent predictor of the primary composite end point (hazard ratio = 1.054; 95% confidence interval, 1.028-1.080; P < .001) and was significantly associated with total mortality (hazard ratio = 1.058; 95% confidence interval, 1.030-1.087; P < .001) and mortality from cardiac causes (hazard ratio = 1.069; 95% confidence interval, 1.026-1.113; P = .001), but not with graft dysfunction (hazard ratio = 1.028; 95% confidence interval, 0.989-1.069; P = .161). For patients with a heart rate ≥ 105 or < 90 bpm vs those with 90-104 bpm, the hazard ratios of the primary end point were 2.233 (95% confidence interval, 1.250-3.989; P = .007) and 0.380 (95% confidence interval, 0.161-0.895; P = .027), respectively. Heart rate tended to decrease in the first 10 years after transplantation (P = .001). Patients with a net increase in heart rate during follow-up showed a higher incidence of adverse events. Conclusions. An elevated heart rate is an adverse prognostic marker after heart transplantation.[Resumen] Introducción y objetivos. Estudiar la evolución y el significado pronóstico de la frecuencia cardiaca tras el trasplante cardiaco. Métodos. Estudio observacional de 170 pacientes que recibieron un trasplante cardiaco bicavo entre 1995 y 2005; todos estaban en ritmo sinusal. La frecuencia cardiaca en reposo se determinó a partir de electrocardiogramas al final del primer año tras el trasplante y anualmente hasta el décimo año. Mediante análisis de Cox, se evaluó la incidencia de eventos adversos en un seguimiento medio de 8,9 ± 3,1 años. El evento principal del estudio fue la variable combinada muerte o disfunción del injerto. Resultados. La frecuencia cardiaca en reposo, medida al final del primer año tras el trasplante, fue un predictor independiente del evento combinado principal (hazard ratio = 1,054; intervalo de confianza del 95%, 1,028-1,080; p < 0,001). Se observó una asociación estadísticamente significativa con la mortalidad total (hazard ratio = 1,058; intervalo de confianza del 95%, 1,030-1,087; p < 0,001) y con la mortalidad por causas cardiacas (hazard ratio = 1,069; intervalo de confianza del 95%, 1,026-1,113; p = 0,001), pero no con la disfunción del injerto (hazard ratio = 1,028; intervalo de confianza del 95%, 0,989-1,069; p = 0,161). Para los pacientes con frecuencia cardiaca ≥ 105 y < 90 lpm frente a aquellos con 90-104 lpm, las hazard ratio del evento principal fueron, respectivamente, 2,233 (intervalo de confianza del 95%, 1,250-3,989, p = 0,007) y 0,380 (intervalo de confianza del 95%, 0,161-0,895; p = 0,027). Este parámetro presentó una tendencia decreciente en los primeros 10 años del trasplante (p = 0,001). Los pacientes con incremento neto de frecuencia cardiaca en el seguimiento mostraron mayor incidencia de eventos adversos. Conclusiones. La frecuencia cardiaca elevada es un marcador pronóstico adverso tras el trasplante cardiaco

    Ischemic postconditioning fails to reduce infarct size in pig models of intermediate and prolonged ischemia

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    This study was funded by the Spanish Ministry of Science and Innovation (“RETOS 2019” grant No PID2019-107332RB-I00 to B.I). B.I is funded by the European Commission (ERC-CoG grant No 819775, and H2020-HEALTH grant No 945118). J.N. is recipient of a predoctoral grant (Jordi Soler Soler) through CIBERCV. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministry of Science and Innovation and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (CEX2020-001041-S).S

    Valor pronóstico del índice de riesgo nutricional en receptores de trasplante cardiaco

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    [Abstract] Introduction and objectives. To study the prognostic impact of preoperative nutritional status, as assessed through the nutritional risk index (NRI), on postoperative outcomes after heart transplantation (HT). Methods. We conducted a retrospective, single-center study of 574 patients who underwent HT from 1991 to 2014. Preoperative NRI was calculated as 1.519 × serum albumin (g/L) + 41.7 × (body weight [kg] / ideal body weight [kg]). The association between preoperative NRI and postoperative outcomes was analyzed by means of multivariable logistic regression and multivariable Cox regression. Results. Mean NRI before HT was 100.9 ± 9.9. According to this parameter, the prevalence of severe nutritional risk (NRI < 83.5), moderate nutritional risk (83.5 ≤ NRI < 97.5), and mild nutritional risk (97.5 ≤ NRI < 100) was 5%, 22%, and 10%, respectively. One year post-transplant mortality rates in these 4 categories were 18.2%, 25.3%, 7.9% and 10.2% (P < .001), respectively. The NRI was independently associated with a lower risk of postoperative infection (adjusted OR, 0.97; 95%CI, 0.95-1.00; P = .027) and prolonged postoperative ventilator support (adjusted OR, 0.96; 95%CI, 0.94-0.98; P = .001). Patients at moderate or severe nutritional risk had significantly higher 1-year post-HT mortality (adjusted HR, 1.55; 95%CI, 1.22-1.97; P < .001). Conclusions. Malnourished patients have a higher risk of postoperative complications and mortality after HT. Preoperative NRI determination may help to identify HT candidates who might benefit from nutritional intervention.[Resumen] Introducción y objetivos. Analizar el impacto del estado nutricional preoperatorio, evaluado mediante el índice de riesgo nutricional (IRN), en el pronóstico tras el trasplante cardiaco (TxC). Métodos. Se realizó un estudio retrospectivo de 574 pacientes que recibieron un TxC entre 1991 y 2014 en un centro. El IRN preoperatorio se calculó como 1,519 × albúmina (g/l) + 41,7 × (peso real [kg] / peso ideal [kg]). La asociación entre IRN preoperatorio y eventos clínicos posoperatorios se analizó mediante modelos multivariables de regresión logística y regresión de Cox. Resultados. El IRN preoperatorio medio de la población del estudio era de 100,9 ± 9,9. Según este parámetro, las prevalencias de riesgo nutricional grave (IRN < 83,5), moderado (83,5 ≤ IRN < 97,5) y leve (97,5 ≤ IRN < 100) antes del TxC eran el 5, el 22 y el 10% respectivamente. Las tasas de mortalidad a 1 año tras el TxC en estas 4 categorías fueron del 18,2, el 25,3, el 7,9 y el 10,2% (p < 0,001) respectivamente. El IRN preoperatorio resultó predictor independiente de menor riesgo de infección posoperatoria (odds ratio ajustada [ORa] = 0,97; intervalo de confianza del 95% [IC95%], 0,95-1,00; p = 0,027) y ventilación mecánica prolongada posoperatoria (ORa = 0,96; IC95%, 0,94-0,98; p = 0,001). Los pacientes con riesgo nutricional moderado a grave mostraron mayor mortalidad a 1 año tras el TxC (hazard ratio ajustada = 1,55; IC95%, 1,22-1,97; p < 0,001). Conclusiones. Los pacientes desnutridos tienen mayor riesgo de complicaciones posoperatorias y muerte tras el TxC. La determinación del IRN podría facilitar la identificación de candidatos a TxC que se beneficien de intervenciones nutricionales en espera del órgano

    In-hospital postoperative infection after heart transplantation: risk factors and development of a novel predictive score

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    [Abstract] Introduction: Infection is one of the most significant complications following heart transplantation (HT). The aim of this study was to identify specific risk factors for early postoperative infections in HT recipients, and to develop a multivariable predictive model to identify HT recipients at high risk. Methods: A single-center, observational, and retrospective study was conducted. The dependent variable was in-hospital postoperative infection. We examined demographic and epidemiological data from donors and recipients, surgical features, and adverse postoperative events as independent variables. Backwards, stepwise multivariable logistic regression with a P-value < 0.05 was used to identify clinical factors independently associated with the risk of in-hospital postoperative infections following HT. Results: Six hundred seventy-seven patients were included in this study. During the in-hospital postoperative period, 348 episodes of infection were diagnosed in 239 (35.9%) patients. Seven variables were identified as independent clinical predictors of early postoperative infection after HT: history of diabetes mellitus, previous sternotomy, preoperative mechanical ventilation, primary graft failure, major surgical bleeding, use of mycophenolate mofetil, and use of itraconazole. Based on the results of multivariable models, we constructed a 7-variable (8-point) score to predict the risk of in-hospital postoperative infection in HT recipients, which showed a reasonable ability to predict the risk of in-hospital postoperative infection in this population. Prospective external validation of this new score is warranted to confirm its clinical applicability. Conclusions: In-hospital postoperative infection is a common complication after HT, affecting 35% of patients who underwent this procedure at our institution. Diabetes mellitus, previous sternotomy, preoperative mechanical ventilation, primary graft failure, major surgical bleeding, use of mycophenolate mofetil, and itraconazole were all independent clinical predictors of early postoperative infection after HT

    Isoprenylcysteine Carboxylmethyltransferase-Based Therapy for Hutchinson-Gilford Progeria Syndrome.

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    Hutchinson-Gilford progeria syndrome (HGPS, progeria) is a rare genetic disease characterized by premature aging and death in childhood for which there were no approved drugs for its treatment until last November, when lonafarnib obtained long-sought FDA approval. However, the benefits of lonafarnib in patients are limited, highlighting the need for new therapeutic strategies. Here, we validate the enzyme isoprenylcysteine carboxylmethyltransferase (ICMT) as a new therapeutic target for progeria with the development of a new series of potent inhibitors of this enzyme that exhibit an excellent antiprogeroid profile. Among them, compound UCM-13207 significantly improved the main hallmarks of progeria. Specifically, treatment of fibroblasts from progeroid mice with UCM-13207 delocalized progerin from the nuclear membrane, diminished its total protein levels, resulting in decreased DNA damage, and increased cellular viability. Importantly, these effects were also observed in patient-derived cells. Using the Lmna G609G/G609G progeroid mouse model, UCM-13207 showed an excellent in vivo efficacy by increasing body weight, enhancing grip strength, extending lifespan by 20%, and decreasing tissue senescence in multiple organs. Furthermore, UCM-13207 treatment led to an improvement of key cardiovascular hallmarks such as reduced progerin levels in aortic and endocardial tissue and increased number of vascular smooth muscle cells (VSMCs). The beneficial effects go well beyond the effects induced by other therapeutic strategies previously reported in the field, thus supporting the use of UCM-13207 as a new treatment for progeria.This work was supported by grants from The Progeria Research Foundation (PRF 2016-65) and the Spanish MINECO (PID2019-106279RB-I00, PID2019-108489RBI00). The authors thank Fundación La Caixa (A.G.), CEI Moncloa (N.I.M.-R.), MINECO (F.J.O.-N. and M.B.) and Ministerio de Ciencia, Innovación y Universidades (N.K.-F.) for predoctoral fellowships. The authors thank C. López-Otín for kindly donating LmnaG609G/G609G progeroid and their corresponding wild-type fibroblasts and UCM’s CAIs Cytometry and Fluorescence Microscopy, Genomics, NMR, and Mass Spectrometry, for their assistance. The CNIC is supported by the Ministerio de Ciencia e Innovación, the Instituto de Salud Carlos III, and the pro-CNIC Foundation, and is a Severo Ochoa Center of Excellence (grant SEV-2015- 0505). The generation of the antiprogerin antibody was funded by the Wellcome Trust (098291/Z/12/Z to S.N.).S

    In-Hospital Post-Operative Infection after Heart Transplantation: Epidemiology, Clinical Management, and Outcome

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    Observational study[Abstract] Background: Infection is a major cause of morbidity and mortality after heart transplantation (HT). Little information about its importance in the immediate post-operative period is available. The aim of this study was to analyze the characteristics, incidence, and outcomes of in-hospital post-operative infections after HT. Methods: We conducted an observational, single-center study based on 677 adults who underwent HT from 1991 to 2015 and who survived the surgical intervention. In-hospital post-operative infections were identified retrospectively according to the medical finding in the clinical records. Results: Over a mean hospital stay of 24.5 days, 239 patients (35.3%) developed 348 episodes of infection (2 episodes per 100 patient-days). The most common sources of infection were those related to invasive procedures (respiratory infections, 115 [33%]; urinary tract infections, 47 [13.5%]; bacteremia, 42 [12.1%]; surgical site infections, 25 [7.2%]), in addition to abdominal focus (33, 9.5%). Enterobacteriaceae (76, 21.8%) and gram-positive cocci (58, 16.7%) were the predominant germs, although opportunistic infections were not infrequent (69, 19.8%). Ninety-five septic episodes were detected with a mean Sequential Organ Failure Assessment Score of 9.5 ± 5.3 points, with hemodynamic failure being the most severe organ dysfunction and renal dysfunction the most frequent one. Management included broad-spectrum antibiotics in 48.8% of episodes and surgical management in 13.8%. The overall antimicrobial success rate was 96.3%. Higher in-hospital mortality was observed among infected patients (15.1% vs. 10.3%), but this difference was not statistically significant (p = 0.067). The one-year survival and events were not different between patients suffering from a post-operative infection and those who did not. Conclusions: In-hospital infections were frequent in the post-operative period after HT and were associated with a poor short-term outcome. Patients who survived sepsis had a similar one-year morbidity and mortality compared with patients who did not develop an infection
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