Publications by authors named "Sergio Rojas"

35 Publications

Safety and efficacy of coronary laser ablation as an adjunctive therapy in percutaneous coronary intervention: a single-centre experience.

Coron Artery Dis 2020 Nov 12. Epub 2020 Nov 12.

Interventional Cardiology Unit, Cardiology Division, Joan XXIII university hospital, Universitat Rovira Virgili, Tarragona, Spain.

Background: Coronary laser is a long-established coadjuvant therapy in interventional cardiology. This study aimed to present our experience regarding the safety and efficacy of laser assistance to percutaneous coronary intervention (PCI) in different scenarios of coronary artery disease.

Methods: We used coronary laser as an adjunctive therapy for PCI between May 2014 and March 2020. The safety of laser ablation was evaluated by studying any complication associated with the laser application. Besides, the laser contribution to PCI and 1 year of follow-up for adverse cardiac events was studied.

Results: Coronary laser was performed in 81 lesions and 75 patients in different scenarios to assist PCI. The average age was 66 ± 11.7 years and 72 (88.9%) were men. Coronary laser was used in 30 (37%) cases for in-stent-material debulking; 26 (32.1%) in primary angioplasty, 19 (23.4%) in chronic total occlusion and 5 (6.2%) in saphenous vein grafts. Procedural success was achieved in 77 (95.1%) with 1 (1.2%) type III coronary perforation. One year of follow-up for combined adverse cardiac events consisting of death due to any cause, myocardial infarction or target vessel failure showed an event-free rate of 0.82 (95% confidence interval, 0.72-0.91).

Conclusions: Our preliminary experience reveals the safety and efficacy of the current modality of coronary laser as a coadjuvant therapy in PCI with a low rate of adverse cardiac events in 1-year of follow-up. Further studies are needed to establish more precisely the contribution of laser application in different contexts of coronary artery disease.
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http://dx.doi.org/10.1097/MCA.0000000000000989DOI Listing
November 2020

Autologous Retinal Transplantation for Primary and Refractory Macular Holes and Macular Hole Retinal Detachments: The Global Consortium.

Ophthalmology 2020 Oct 10. Epub 2020 Oct 10.

Associated Retinal Consultants, PC, Department of Ophthalmology, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan. Electronic address:

Purpose: To report the anatomic and functional outcomes of autologous retinal transplantation (ART).

Design: Multicenter, retrospective, interventional, consecutive case series.

Participants: One hundred thirty eyes of 130 patients undergoing ART for the repair of primary and refractory macular holes (MHs), as well as combined MH-rhegmatogenous retinal detachment (MH-RRD), between January 2017 and December 2019.

Methods: All patients underwent pars plana vitrectomy and ART, with surgeon modification of intraoperative variables. A large array of preoperative, intraoperative, and postoperative data was collected. Two masked reviewers graded OCT images. Multivariate statistical analysis and subgroup analysis were performed.

Main Outcome Measures: Macular hole closure rate, visual acuity (VA), external limiting membrane and ellipsoid zone (EZ) band integrity, and alignment of neurosensory layers (ANL) on OCT.

Results: One hundred thirty ART surgeries were performed by 33 vitreoretinal surgeons worldwide. Patient demographics were: mean age of 63 ± 6.3 years, 58% female, 41% White, 23% Black, 19% Asian, and 17% Latino. Preoperative VA was 1.37 ± 0.12 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, approximately 20/500), which improved significantly to 1.05 ± 0.09 logMAR (Snellen equivalent, approximately 20/225; P < 0.001) after surgery (mean follow-up, 8.6 ± 0.8 months). Autologous retinal transplantation was performed for primary MH repair in 27% of patients (n = 35), for refractory MH in 58% of patients (n = 76; mean number of previous surgeries, 1.6 ± 0.2), and for MH-RRD in 15% of patients (n = 19). Mean maximum MH diameter was 1470 ± 160 μm, mean minimum diameter was 840 ± 94 μm, and mean axial length was 24.6 ± 3.2 mm. Overall, 89% of MHs closed (78.5% complete; 10% small eccentric defect), with a 95% closure rate in MH-RRD (68.4% complete; 26.3% small eccentric defect). Visual acuity improved by at least 3 lines in 43% of eyes and by at least 5 lines in 29% of eyes. Reconstitution of the EZ (P = 0.02) and ANL (P = 0.01) on OCT were associated with better final VA. Five cases of ART graft dislocation (3.8%), 5 cases of postoperative retinal detachment (3.8%), and 1 case of endophthalmitis (0.77%) occurred.

Conclusions: In this global experience, patients undergoing ART for large primary and refractory MHs and MH-RRDs achieved good anatomic and functional outcomes, with low complication rates despite complex surgical pathologic features.
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http://dx.doi.org/10.1016/j.ophtha.2020.10.007DOI Listing
October 2020

Soluble urokinase plasminogen activator receptor as a long-term prognostic biomarker in acute coronary syndromes.

Biomarkers 2020 Jul 18;25(5):402-409. Epub 2020 Jun 18.

Department of Cardiology, Joan XXIII University Hospital, Tarragona, Spain.

The aim of our study was to analyse the long-term prognostic value of soluble urokinase plasminogen activator receptor (suPAR) in the setting of an acute coronary syndrome (ACS). We included 340 patients with an ACS who underwent coronary angiography and plasma suPAR concentration was measured. Patients were classified into low suPAR concentrations (<2.6 ng/mL) and high suPAR concentrations (≥2.6 ng/mL) and long-term events were evaluated. suPAR prognostic value was assessed beyond a clinical model that included age, GRACE score, estimated glomerular filtration rate, cardiac troponin-I peak and left ventricular ejection fraction <40%. Higher suPAR concentrations were associated with an increased prevalence of cardiovascular risk factors. After multivariate adjustment, suPAR ≥2.6 ng/mL were independently associated with an increased risk of all-cause death (HR 2.3; 95%CI 1.2-4.4;  = .017), major adverse cardiovascular events (MACE) (HR 1.7; 95%CI 1.1-2.5;  = .020) and heart failure (HR 4.1; 95%CI 1.3-12.6;  = .015), but not with myocardial infarction. For long-term all-cause death significant improvement of reclassification and discrimination were seen after addition of suPAR to a clinical model. In the setting of an ACS, suPAR is associated with long-term all-cause death, heart failure and MACE, and provides incremental prognostic value beyond traditional risks factors.
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http://dx.doi.org/10.1080/1354750X.2020.1778090DOI Listing
July 2020

Effects of support and reaction pressure for the synthesis of dimethyl ether over heteropolyacid catalysts.

Sci Rep 2020 May 22;10(1):8551. Epub 2020 May 22.

Grupo de Energía y Química Sostenibles (EQS). Instituto de Catálisis y Petroleoquímica CSIC. C/Marie Curie 2, 28049, Madrid, Spain.

Dimethyl ether (DME) is an advanced second-generation biofuel produced via methanol dehydration over acid catalysts such as γ-AlO, at temperatures above 240 °C and pressures above 10 bar. Heteropolyacids such as tungstosilicic acid (HSiW) are Brønsted acid catalysts with higher DME production rates than γ-AlO, especially at low temperatures (140-180 °C). In this work, we show that the performance of supported HSiW for the production of DME is strongly affected by the nature of the support. TiO and SiO supported HSiW display the highest DME production rates of ca. 50 mmol/h/g. Characterization of acid sites via H-NMR, NH-isotherms and NH-adsrobed DRIFT reveal that HSiW/X have Brønsted acid sites, HSiW/TiO showing more and stronger sites, being the most active catalyst. Methanol production increases with T until 200 °C where a rapid decay in methanol conversion is observed. This effect is not irreversible, and methanol conversion increases to ca. 90% by increasing reaction pressure to 10 bar, with DME being the only product detected at all reaction conditions studied in this work. The loss of catalytic activity with the increasing temperature and its increasing with reaction pressure accounts to the degree of contribution of the pseudo-liquid catalysis under the reaction conditions studied.
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http://dx.doi.org/10.1038/s41598-020-65296-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7244519PMC
May 2020

Comparison of clinical outcomes in STEMI patients treated with primary PCI according to day-time of medical attention and its relationship with circadian pattern.

Int J Cardiol 2020 04 21;305:35-41. Epub 2020 Jan 21.

Clinic Cardiovascular Institute, Department of Cardiology, Hospital Clinic, Biomedical Investigation Institute, IDIBAPS, University of Barcelona, Spain.

Objective: Relationship between STEMI time of presentation, its circadian pattern and cardiovascular outcomes is unclear. Our objective is to analyze clinical outcomes of STEMI according to time of presentation and circadian pattern.

Methods: We analyzed data from patients treated within the regional STEMI Network from January 2010 to December 2015. On-hour group included patients treated between 8:00 h and 19:59 h on weekdays, the rest were catalogued as off-hour group. The primary endpoint was 1-year all-cause mortality. Secondary endpoints were 30-day all-cause mortality and in-hospital complications.

Results: A total of 8608 patients were included, 44.1% in the on-hour group and 55.9% in the off-hour group. We observed a shorter patient delay and longer system delay in the off-hour group compared to on-hour group with no difference in total ischemic time. At 30-day and 1-year follow-up there were no differences in adjusted all-cause mortality between groups [OR 0.91 (CI95%: 0.73-1.12; p = 0.35) and OR 0.99 (CI95%: 0.83-1.17; p = 0.87), respectively]. A circadian pattern was observed between 9:00 am and 12:30 pm, with no differences in 30-day and 1-year mortality between patients included in this time interval [OR 1.02 (IC95%: 0.81-1.30; p = 0.85) and OR 1.12 (IC95%: 0.92-1.36; p = 0.25) respectively].

Conclusions: Off-hour STEMI presentation was associated with a shorter patient delay and longer system delay without an increase in total ischemic time. The off-hour presentation was not related to an increase in 1-year all-cause mortality when compared to on-hour. A circadian pattern was found, without differences in 30-day and 1-year mortality.
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http://dx.doi.org/10.1016/j.ijcard.2020.01.041DOI Listing
April 2020

Diabetes mellitus is not independently associated with mortality in elderly patients with ST-segment elevation myocardial infarction. Insights from the Codi Infart registry.

Coron Artery Dis 2020 01;31(1):1-6

Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona.

Background: Diabetes mellitus predicts poorer outcomes in patients with acute coronary syndrome (ACS), but the magnitude of this association in patients at older ages remains controversial.

Methods: Data were extracted from the Codi Infart database. All consecutive patients with diagnosis of ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) between 2010 and 2015 were included. We assessed the impact of diabetes mellitus on 30-day and one-year mortality in patients aged less than and at least 75 years.

Results: A total of 12 792 cases were registered, of whom 3023 (23.6%) were aged at least 75 years. About 20% patients had previous diabetes mellitus diagnosis. Patients aged at least 75 years had higher prevalence of comorbidities, higher proportion of heart failure at admission, a more extensive coronary artery disease and significant delay to reperfusion (P < 0.001). Diabetes mellitus was associated with higher 30-day mortality both in young [odds ratio (OR) 1.97, 95% confidence interval (CI): 1.43-2.70] and in elderly patients (OR 1.43, 95% CI: 1.07-1.91). After adjusting for potential confounders, this association remained significant in young patients (OR 1.47, 95% CI: 1.00-2.16, P = 0.047), but not in the elderly (OR 1.14, P = 0.43). Likewise, a crude association between diabetes mellitus and one-year mortality was observed in both groups (young patients: HR = 1.93; 95% CI: 1.51-2.46; older patients: HR = 1.33; 95% CI: 1.08-1.64). However, after adjusting for potential confounders, this association remained significant in younger patients (HR = 1.46; 95% CI: 1.13-1.89; P < 0.001), but not in the elderly (HR = 1.16; P = 0.17).

Conclusion: A significant proportion of these nonselected patients with STEMI had previous diabetes mellitus. The association between diabetes mellitus and outcomes is different according to age.
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http://dx.doi.org/10.1097/MCA.0000000000000821DOI Listing
January 2020

Stromal cell derived factor-1 and long-term prognosis in acute coronary syndrome.

Biomark Med 2019 10 27;13(14):1187-1198. Epub 2019 Sep 27.

Department of Cardiology, Joan XXIII University Hospital, Tarragona, Spain.

To explore long-term prognostic value of SDF-1 in acute coronary syndrome (ACS). We included 254 patients with ACS. Plasma SDF-1 was measured and patients were classified into tertiles of SDF-1. Multivariate analysis showed third tertile of SDF-1 as an independent predictor of all-cause death (HR: 2.5; 95% CI: 1.2-5.2; p = 0.011) and the composite of major adverse cardiovascular and cerebrovascular events (HR: 1.8; 95% CI: 1.1-3.1; p = 0.031). SDF-1 added to a clinical model can improve all-cause death prediction (net reclassification improvement 0.362; 95% CI: 0.423-0.681; p = 0.027). SDF-1 is an independent predictor of all-cause mortality and major adverse cardiovascular and cerebrovascular events in long-term follow-up of patients with ACS and adds prognostic information beyond traditional cardiovascular risks factors.
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http://dx.doi.org/10.2217/bmm-2019-0133DOI Listing
October 2019

Excimer Laser in Percutaneous Coronary Intervention of Device Uncrossable Chronic Total and Functional Occlusions.

Cardiovasc Revasc Med 2020 05 24;21(5):657-660. Epub 2019 Aug 24.

Interventional Cardiology Unit, Cardiology Division, Joan XXIII University Hospital, Universitat Rovira Virgili, Calle Dr Mallafré Guasch 4, 43007 Tarragona, Spain.

Device uncrossable lesions are a challenge in interventional cardiology and despite improvements in balloon and microcatheter profile, rotational atherectomy is necessary in some circumstances in order to ablate and traverse the lesion. Nevertheless, the application of rotational atherectomy requires utilization of a specific wire, Rotawire, which is not always so easily navigable. Debulking of device uncrossable lesions can be performed by coronary laser over any kind of angioplasty guidewire. We present a series of six patients with chronic total (100%) and functional occlusions (99% stenosis) in whom after successful wire crossing, microcatheter failed to traverse the lesion. After coronary laser performance, 5 out of 6 lesions were successfully dilated, achieving a successful final angiographic result of 83.3%.
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http://dx.doi.org/10.1016/j.carrev.2019.08.022DOI Listing
May 2020

Long-term prognostic value of growth differentiation factor-15 in acute coronary syndromes.

Clin Biochem 2019 Nov 29;73:62-69. Epub 2019 Jul 29.

Department of Cardiology, Joan XXIII University Hospital, Tarragona, Spain; Pere Virgili Health Research Institute, Rovira i Virgili University, Tarragona, Spain. Electronic address:

Background: Growth Differentiation Factor-15 (GDF-15) predicts death and cardiovascular events in acute coronary syndromes (ACS). We aimed to assess the long-term prognostic value of GDF-15 in ACS.

Methods: We included 358 patients with ACS who underwent coronary angiography. Plasma GDF-15 was measured and clinical data and long-term events were registered. Incremental value of GDF-15 for prognosing all-cause death above a clinical model including GRACE score, left ventricular ejection fraction <40%, prior myocardial infarction and age was assessed.

Results: GDF-15 concentrations >1800 ng/L were associated with an increased prevalence of cardiovascular risk factors. During 6.5 years of follow-up 56 patients died, 7 had values of GDF-15 < 1200 ng/L, 7 between 1200 and 1800 ng/L and 42 > 1800 ng/L. After adjustment for potential confounders, GDF-15 > 1800 ng/L were independently associated with all-cause death (HR 4.09; 95% CI 1.57-10.71; p = .004) and the composite of major adverse cardiovascular events (MACE) (HR 2.48; 95% CI 1.41-4.34; p = .001). For long-term all-cause death a significant increase of ROC curve was seen after addition of GDF-15 to a clinical model 0.876 (95% CI 0.823-0.928; p = .014). Same improvements were found for net reclassification improvement (0.776; 95% CI 0.494-1.037; p < .001) and integrated discrimination improvement (0.112; 95% CI 0.055-0.169; p < .001). Multivariate competing risk model showed a significant association between GDF-15 > 1800 ng/L and the incidence of heart failure but not of myocardial infarction.

Conclusions: In the setting of ACS, GDF-15 is associated with long-term all-cause death, MACE and heart failure and provides incremental prognostic value beyond traditional risks factor.
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http://dx.doi.org/10.1016/j.clinbiochem.2019.07.014DOI Listing
November 2019

Persistence with dual antiplatelet therapy after percutaneous coronary intervention for ST-segment elevation acute coronary syndrome: a population-based cohort study in Catalonia (Spain).

BMJ Open 2019 07 23;9(7):e028114. Epub 2019 Jul 23.

Cardiology Department, Vall d'Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.

Objectives: Guidelines recommending 12-month dual antiplatelet therapy (DAPT) in patients with ST-elevation acute coronary syndrome (STEACS) undergoing percutaneous coronary intervention (PCI) were published in year 2012. We aimed to describe the influence of guideline implementation on the trend in 12-month persistence with DAPT between 2010 and 2015 and to evaluate its relationship with DAPT duration regimens recommended at discharge from PCI hospitals.

Design: Observational study based on region-wide registry data linked to pharmacy billing data for DAPT follow-up.

Setting: All PCI hospitals (10) belonging to the acute myocardial infarction (AMI) code network in Catalonia (Spain).

Participants: 10 711 STEACS patients undergoing PCI between 2010 and 2015 were followed up.

Primary And Secondary Outcome Measures: Primary outcome was 12-month persistence with DAPT. Calendar year quarter, publication of guidelines, DAPT duration regimen recommended in the hospital discharge report, baseline patient characteristics and significant interactions were included in mixed-effects logistic regression based interrupted time-series models.

Results: The proportion of patients on-DAPT at 12 months increased from 58% (56-60) in 2010 to 73% (71-75) in 2015. The rate of 12-month persistence with DAPT significantly increased after the publication of clinical guidelines with a time lag of 1 year (OR=1.20; 95% CI 1.11 to 1.30). A higher risk profile, more extensive and complex coronary disease, use of drug-eluting stents (OR=1.90; 95% CI 1.50 to 2.40) and a 12-month DAPT regimen recommendation at discharge from the PCI hospital (OR=5.76; 95% CI 3.26 to 10.2) were associated with 12-month persistence.

Conclusion: Persistence with 12-month DAPT has increased since publication of clinical guidelines. Even though most patients were discharged on DAPT, only 73% with potential indication were on-DAPT 12 months after PCI. A guideline-based recommendation at PCI hospital discharge was highly associated with full persistence with DAPT. Establishing evidence-based, common prescribing criteria across hospitals in the AMI-network would favour adherence and reduce variability.
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http://dx.doi.org/10.1136/bmjopen-2018-028114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661631PMC
July 2019

Combining computer vision and deep learning to enable ultra-scale aerial phenotyping and precision agriculture: A case study of lettuce production.

Hortic Res 2019 1;6:70. Epub 2019 Jun 1.

1Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ UK.

Aerial imagery is regularly used by crop researchers, growers and farmers to monitor crops during the growing season. To extract meaningful information from large-scale aerial images collected from the field, high-throughput phenotypic analysis solutions are required, which not only produce high-quality measures of key crop traits, but also support professionals to make prompt and reliable crop management decisions. Here, we report AirSurf, an automated and open-source analytic platform that combines modern computer vision, up-to-date machine learning, and modular software engineering in order to measure yield-related phenotypes from ultra-large aerial imagery. To quantify millions of in-field lettuces acquired by fixed-wing light aircrafts equipped with normalised difference vegetation index (NDVI) sensors, we customised AirSurf by combining computer vision algorithms and a deep-learning classifier trained with over 100,000 labelled lettuce signals. The tailored platform, AirSurf-, is capable of scoring and categorising iceberg lettuces with high accuracy (>98%). Furthermore, novel analysis functions have been developed to map lettuce size distribution across the field, based on which associated global positioning system (GPS) tagged harvest regions have been identified to enable growers and farmers to conduct precision agricultural practises in order to improve the actual yield as well as crop marketability before the harvest.
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http://dx.doi.org/10.1038/s41438-019-0151-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544649PMC
June 2019

LaSrNiMnRuO Double Perovskite with Enhanced ORR/OER Bifunctional Catalytic Activity.

ACS Appl Mater Interfaces 2019 Jun 5;11(24):21454-21464. Epub 2019 Jun 5.

Department of Chemistry and Chemical Biology , Rutgers, The State University of New Jersey , 610 Taylor Road , Piscataway , New Jersey 08854 , United States.

Perovskites (ABO) with transition metals in active B sites are considered alternative catalysts for the water oxidation to oxygen through the oxygen evolution reaction (OER) and for the oxygen reduction through the oxygen reduction reaction (ORR) back to water. We have synthesized a double perovskite (ABB'O) with different cations in A, B, and B' sites, namely, (LaSr)(NiMn)(NiRu)O (LSNMR), which displays an outstanding OER/ORR bifunctional performance. The composition and structure of the oxide has been determined by powder X-ray diffraction, powder neutron diffraction, and transmission electron microscopy to be monoclinic with the space group P2/ n and with cationic ordering between the ions in the B and B' sites. X-ray absorption near-edge spectroscopy suggests that LSNMR presents a configuration of ∼Ni, ∼Mn, and ∼Ru. This bifunctional catalyst is endowed with high ORR and OER activities in alkaline media, with a remarkable bifunctional index value of ∼0.83 V (the difference between the potentials measured at -1 mA cm for the ORR and +10 mA cm for the OER). The ORR onset potential ( E) of 0.94 V is among the best reported to date in alkaline media for ORR-active perovskites. The ORR mass activity of LSNMR is 1.1 A g at 0.9 V and 7.3 A g at 0.8 V. Furthermore, LSNMR is stable in a wide potential window down to 0.05 V. The OER potential to achieve a current density of 10 mA cm is 1.66 V. Density functional theory calculations demonstrate that the high ORR/OER activity of LSNMR is related to the presence of active Mn sites for the ORR- and Ru-active sites for the OER by virtue of the high symmetry of the respective reaction steps on those sites. In addition, the material is stable to ORR cycling and also considerably stable to OER cycling.
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http://dx.doi.org/10.1021/acsami.9b02077DOI Listing
June 2019

Na-doped ruthenium perovskite electrocatalysts with improved oxygen evolution activity and durability in acidic media.

Nat Commun 2019 05 3;10(1):2041. Epub 2019 May 3.

Grupo de Energía y Química Sostenible, Instituto de Catálisis y Petroleoquímica, CSIC. C/ Marie Curie 2, 28049, Madrid, Spain.

The design of active and durable catalysts for the HO/O interconversion is one of the major challenges of electrocatalysis for renewable energy. The oxygen evolution reaction (OER) is catalyzed by SrRuO with low potentials (ca. 1.35 V), but the catalyst's durability is insufficient. Here we show that Na doping enhances both activity and durability in acid media. DFT reveals that whereas SrRuO binds reaction intermediates too strongly, Na doping of ~0.125 leads to nearly optimal OER activity. Na doping increases the oxidation state of Ru, thereby displacing positively O p-band and Ru d-band centers, weakening Ru-adsorbate bonds. The enhanced durability of Na-doped perovskites is concomitant with the stabilization of Ru centers with slightly higher oxidation states, higher dissolution potentials, lower surface energy and less distorted RuO octahedra. These results illustrate how high OER activity and durability can be simultaneously engineered by chemical doping of perovskites.
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http://dx.doi.org/10.1038/s41467-019-09791-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6499887PMC
May 2019

Enhanced biosorption of Cr(VI) using cotton fibers coated with chitosan - role of ester bonds.

Water Sci Technol 2018 Sep;78(3-4):476-486

Civil and Environmental Engineering, Universidad de los Andes, Cr 1 este no. 19A-40, Bogotá, Colombia E-mail:

We report on the role of ester bonds in the enhanced removal of hexavalent chromium from water using cotton fibers coated with chitosan. Adsorption capacities up to five times higher than those of the unmodified fibers were observed when the cotton fibers were exposed to an NaOH, followed by citric acid (0.97 M), and a chitosan solution (2%). We found that the use of NaOH favors the formation of ester bonds over amide bonds on the surface of the cotton fibers. This increase in the surface density of ester bonds generates an increase in the amount of exposed amino groups from the chitosan, hence increasing the removal capacity of the modified fibers. Experimental results also reveal that the adsorption is induced by the electrostatic attraction between the protonated amino groups on the surface and the negatively charged chromium ions in the water. Adsorption isotherms and kinetic studies indicated that the adsorption process fits the Langmuir and the Freundlich isotherm models as well as the pseudo-first and pseudo-second order kinetic models. These results can open a new avenue for the manufacturing of fibers with enhanced removal capacities for hexavalent chromium.
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http://dx.doi.org/10.2166/wst.2018.284DOI Listing
September 2018

Procedural, Functional and Prognostic Outcomes Following Recanalization of Coronary Chronic Total Occlusions. Results of the Iberian Registry.

Rev Esp Cardiol (Engl Ed) 2019 May 25;72(5):373-382. Epub 2018 Jun 25.

Servicio de Cardiología, Hospital Espírito Santo, Evora, Portugal.

Introduction And Objectives: There is current controversy regarding the benefits of percutaneous recanalization (PCI) of chronic total coronary occlusions (CTO). Our aim was to determine acute and follow-up outcomes in our setting.

Methods: Two-year prospective registry of consecutive patients undergoing PCI of CTO in 24 centers.

Results: A total of 1000 PCIs of CTO were performed in 952 patients. Most were symptomatic (81.5%), with chronic ischemic heart disease (59.2%). Previous recanalization attempts had been made in 15%. The mean SYNTAX score was 19.5 ± 10.6 and J-score was > 2 in 17.3%. A retrograde procedure was performed in 92 patients (9.2%). The success rate was 74.9% and was higher in patients without previous attempts (82.2% vs 75.2%; P = .001), those with a J-score ≤ 2 (80.5% vs 69.5%; P = .002), and in intravascular ultrasound-guided PCI (89.9% vs 76.2%, P = .001), which was an independent predictor of success. In contrast, severe calcification, length > 20mm, and blunt proximal cap were independent predictors of failed recanalization. The rate of procedural complications was 7.1%, including perforation (3%), myocardial infarction (1.3%), and death (0.5%). At 1-year of follow-up, 88.2% of successfully revascularized patients showed clinical improvement (vs 34.8%, P < .001), which was associated with lower mortality. At 1-year of follow-up, the mortality rate was 1.5%.

Conclusions: Compared with other national registries, patients in the Iberian registry undergoing PCI of a CTO showed similar complexity, success rate, and complications. Successful recanalization was strongly associated with functional improvement, which was related to lower mortality.
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http://dx.doi.org/10.1016/j.rec.2018.05.020DOI Listing
May 2019

Procedure Time Comparison between Radial Versus Femoral Access in ST-Segment Elevation Acute Myocardial Infarction Patients Undergoing Emergent Percutaneous Coronary Intervention: A Meta-analysis of Controlled Randomized Trials.

Heart Views 2018 Jan-Mar;19(1):1-7

Department of Interventional Cardiology, Cardiology Division, Joan XXIII University Hospital, Tarragona, Spain.

Introduction: There are inconclusive data about the potential delay of procedure time in emergent percutaneous coronary intervention (PCI) by radial compared with femoral approach in patients with ST-segment elevation myocardial infarction (STEMI).

Aims: The purpose of the current study is to conduct a comprehensive meta-analysis of controlled randomized trials (CRTs) comparing the procedure time in STEMI patients undergoing emergent PCI with radial versus femoral access.

Methods: Formal search of CRTs through electronic databases (Medline and PubMed) was performed from January 1990 to October 2014 without language restrictions. Mean difference (MD) of procedure time was evaluated as overall effect.

Results: Twelve studies were included with 2052 and 2121 patients in radial and femoral group, respectively. Variability in the definition of procedure time was found with unavailability of a precise definition in 41.6% of studies. When all studies were included, no significant longer procedure time in radial approach was detected (MD [95% confidence interval [CI] = 1.6 min [-0.10, 3.3], = 0.07, het = 0.56). After deleting RIVAL trial, procedure time was significantly longer in radial group (MD [95% CI] = 1.5 min [0.71, 2.3], < 0.001, het = 0.20). Meta-analysis of three studies with similar definition of procedure time showed (MD [95% CI] = 1.26 min [-0.43, 2.95], = 0.14, het = 0.85).

Conclusions: Although the procedure time in STEMI patients undergoing emergent PCI by radial access is generally comparable with femoral approach, there is an absence of uniformity in its definition, which leads to divergent results. A standardized definition of procedure time is required to elucidate this relevant matter.
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http://dx.doi.org/10.4103/HEARTVIEWS.HEARTVIEWS_82_16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5965007PMC
June 2018

Yellow (577 nm) micropulse laser versus half-dose verteporfin photodynamic therapy in eyes with chronic central serous chorioretinopathy: results of the Pan-American Collaborative Retina Study (PACORES) Group.

Br J Ophthalmol 2018 12 8;102(12):1696-1700. Epub 2018 Feb 8.

Clinica Oftalmologica Centro Caracas and the Arevalo-Coutinho Foundation for Research in Ophthalmology, Caracas, Venezuela.

Purpose: To compare the functional and anatomical outcomes of eyes with chronic central serous chorioretinopathy treated with yellow micropulse (MP) laser versus half-dose verteporfin photodynamic therapy (PDT).

Methods: This is a multicentre, retrospective comparative study of 92 eyes treated with yellow MP laser (duty cycle of 5%, zero spacing between spots, spot size varied from 100 to 200 µm, power varied from 320 to 660 mW, and the pulse burst duration was 200 ms) and 67 eyes treated with PDT (half-dose verteporfin (3 mg/m) infused over 10 min), followed by laser activation for 83 s. Spot sizes varied from 400 to 2000 µm.

Results: In the MP group, at 12 months of follow-up, the mean best corrected visual acuity (BCVA) improved from the logarithm of the minimum angle of resolution (logMAR) of 0.41±0.27 at baseline to 0.21±0.26 (P<0.0001), 48.9% (45/92) of eyes had an improvement of ≥3 lines of BCVA from baseline, 48.9% (45/92) of eyes remained within 2 lines of baseline BCVA, and only 2.2% (2/92) of eyes lost ≥3 lines of BCVA from baseline. In the PDT group, at 12 months of follow-up, the mean BCVA changed from logMAR of 0.50±0.34 at baseline to 0.47±0.34 (P=0.89), 19% (13/67) of eyes had an improvement of ≥3 lines of BCVA from baseline, 73% (49/67) of eyes remained within 2 lines of baseline BCVA, and 7% (5/67) of eyes lost ≥3 lines of BCVA from baseline. There were no adverse events attributable to the yellow MP laser treatment. One eye in the PDT group developed choroidal neovascularisation, which was treated with three intravitreal bevacizumab injections.

Conclusions: Both PDT and MP are effective in restoring the macular anatomy. In places where PDT is not available, yellow MP laser may be an adequate treatment alternative.
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http://dx.doi.org/10.1136/bjophthalmol-2017-311291DOI Listing
December 2018

Intravitreal bevacizumab monotherapy in myopic choroidal neovascularisation: 5-year outcomes for the PAN-American Collaborative Retina Study Group.

Br J Ophthalmol 2018 04 16;102(4):455-459. Epub 2017 Aug 16.

Retina Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

Purpose: To report the long-term anatomical and visual outcomes of intravitreal bevacizumab (IVB) monotherapy in naive choroidal neovascularisation (CNV) caused by myopia.

Methods: Retrospective analysis of naive CNV secondary to myopia that underwent antivascular endothelial growth factor monotherapy was performed. Collected data included demographic details, clinical examination details including visual acuity at presentation and follow-up with imaging and treatment details. Main outcome measures were resolution of CNV activity at the last visit. Secondary outcomes included change in visual acuity, number of injections and adverse events.

Results: Thirty-three eyes of 31 subjects with a mean age of 51.48±16.4 years were included. The mean follow-up was 66.47 months. 27 eyes had type 2 CNV and the rest seven eyes had type 1 CNV. The mean number of IVB injections per eye was 4.9. Mean visual acuity at baseline reduced from 0.65±0.33 logMAR units (Snellen equivalent=20/89) to 0.73±0.50 logMAR units (20/107) at final follow-up (p=0.003). The mean central macular thickness decreased from 309.31±86 µm at baseline to 267.5±70.89 µm at the last visit (p=0.03). However, visual acuity was maintained (±1 line of baseline) in 13 eyes (39.4%), ≥2 line improvement in nine (27.3%) eyes and more than two lines worsening in 11 eyes (33.3%). Foveal atrophy was observed at baseline and last visit in 6 (12.5%) and 14 (29.1%), respectively (p=0.007). No systemic adverse events were observed.

Conclusion: IVB monotherapy is safe and effective for long-term treatment of CNV secondary to myopia in real life.
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http://dx.doi.org/10.1136/bjophthalmol-2017-310411DOI Listing
April 2018

Percutaneous retrieval of a port-a-cath using a pigtail catheter combined with snaring technique.

Cardiovasc Revasc Med 2017 Dec 8;18(8):607-610. Epub 2017 Jul 8.

Interventional Cardiology Unit, Cardiology Division, Joan XXIII University Hospital, Universitat Rovira Virgili, Calle Dr Mallafré Guasch 4, 43007 Tarragona, Spain.

We present a case of a 63-year-old woman who underwent chemotherapy for breast cancer through a port-a-cath inserted in left subclavian vein. The device was withdrawn one year later due to jugular vein thrombosis plus dysfunction of the device. A few years later a chest X-ray for scrutinizing dyspnea showed a catheter located in right heart chambers. Percutaneous retrieval via right subclavian vein was planned. Both catheter ends were impacted against heart structures and were not free to be easily captured by a snare. By using a pig-tail catheter we were able to seize the catheters loop portion and pull it back slightly. Once the catheter ends became free we seized one of the catheter's distal ends with a snare and successfully externalised it.
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http://dx.doi.org/10.1016/j.carrev.2017.07.001DOI Listing
December 2017

Reconstruction of an accidentally crushed stent guided by intravascular ultrasound during a left main percutaneous coronary intervention.

Rev Port Cardiol 2017 May 4;36(5):389.e1-389.e5. Epub 2017 May 4.

Interventional Cardiology Department, Cardiology Division, Joan XXIII University Hospital, Tarragona, Spain.

We present a case of an accidentally crushed stent due to an unnoticed passage of a guidewire through a lateral stent strut with subsequent stent compression after balloon dilatation, during a planned percutaneous coronary intervention on the left main. The crushed stent segment was reconstructed with step-by-step balloon dilation, guided by intravascular ultrasound.
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http://dx.doi.org/10.1016/j.repc.2016.03.015DOI Listing
May 2017

[Negative angiographic markers in percutaneous coronary intervention of chronic total occlusions].

Arch Cardiol Mex 2018 Apr - Jun;88(2):93-99. Epub 2017 Mar 6.

Unidad de Hemodinámica, Servicio de Cardiología, Hospital Universitario Joan XXIII, IISPV, Universitat Rovira i Virgili, Tarragona, España.

Objective: The purpose of this study is to identify negative angiographic predictive variables and the presence of a side branch close to the distal cap of the occlusion in the chronic total occlusion percutaneous coronary intervention outcome.

Methods: Potential negative angiographic variables were retrospectively evaluated in 156 chronic total occlusions that had undergone a percutaneous coronary intervention. Binary logistic regression with predictive purpose was used to identify a model of variables which, all in all, could successfully predict a negative intervention result.

Results: Variables independently associated with the procedural failure were multivessel disease (odds ratio=5.12; 95% confidence interval (CI); 1.94-13.5; P=.001), ambiguous stump presence (odds ratio=5.08; 95% CI; 2.22-11.63 P<.001), occlusion length ≥20mm (odds ratio=3.7; 95% CI; 1.37-9.97 P=.01), and ostial location (odds ratio=6.53; 95% CI; 1.67-25.63; P=.007). Side branch at distal cap proximity did not remain in the predictive model.

Conclusions: Multivessel disease, ambiguous stump, a length ≥20mm, and an ostial location of a chronic total occlusion are independent predictive factors of an unfavourable angioplasty result. A side branch at occlusion distal cap was not associated with the procedural failure.
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http://dx.doi.org/10.1016/j.acmx.2017.01.008DOI Listing
February 2019

Efficacy and safety of Tornus catheter in percutaneous coronary intervention of hard or balloon-uncrossable chronic total occlusion.

ARYA Atheroscler 2016 Jul;12(4):206-211

Professor, Cardiology Division, Joan XXIII University Hospital, Universitat Rovira i Virgili, Tarragona, Spain.

Background: Balloon advancement and dilation through chronic total occlusion segment could be challenging in some cases after successful wire crossing. The purpose of this study was to evaluate efficacy and safety of Tornus catheter (Asahi Intecc; Aichi, Japan) in percutaneous coronary intervention of chronic total occlusion in hard or balloon-uncrossable chronic total occlusion.

Methods: The present study is a retrospective and descriptive analysis of 14 hard or balloon-uncrossable chronic total occlusions treated percutaneously in our catheterization laboratory (cath lab). Tornus catheter was used to penetrate and eventually cross the chronic total occlusion segment. Procedure success was defined when Tornus penetrated at least partly into chronic total occlusion segment making possible the subsequent balloon dilatation and stent implantation achieving a final TIMI III angiographic result with residual stenosis less than 30%. Switch to other microcatheter was considered as an unsuccessful procedure. Complications associated with the Tornus use were analyzed in order to evaluate device safety.

Results: The average age of patients was 65.2 ± 9.6 and 11 out of 14 (78.6%) were male. In 7 (50%) cases, Tornus was used after an unsuccessful balloon passage through occluded segment. In 11 (78.6%) out of 14 cases the procedure was successful and in 3 (21.4%) cases, the operator switched to another microcatheter to continue with the procedure. No complication occurred during all procedures.

Conclusion: Tornus catheter can be effectively and safely used in a subgroup of patients undergoing percutaneous coronary intervention of chronic total occlusion with hard or balloon-uncrossable lesions and could facilitate the treatment of this type of lesions.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5266139PMC
July 2016

Embolization of a septal branch perforation using subcutaneous fat during a percutaneous coronary intervention of chronic total occlusion by retrograde approach.

J Saudi Heart Assoc 2017 Jan 28;29(1):60-65. Epub 2016 May 28.

Interventional Cardiology Unit, Cardiology Division, Joan XXIII University Hospital, Tarragona, Spain.

We describe a case of septal branch perforation during percutaneous coronary intervention of a right coronary artery chronic total occlusion. The septal branch perforation was treated with administration of autologous fat into the septal branch with significant reduction of extravasation. This treatment was followed by prolonged balloon inflation at the exit point of the septal branch in the donor artery which definitively sealed the perforation.
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http://dx.doi.org/10.1016/j.jsha.2016.05.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247294PMC
January 2017

Percutaneous coronary intervention of chronically occluded saphenous vein grafts using excimer laser atherectomy as an adjuvant therapy.

Cardiovasc Revasc Med 2017 Sep 27;18(6S1):2-6. Epub 2016 Dec 27.

Cardiology Division, Joan XXIII University Hospital, Universitat Rovira Virgili, Calle Dr Mallafré Guasch 4, 43007. Electronic address:

We present two cases with chronic total occlusion of the saphenous vein graft in two patients with a history of previous bypass surgery with unfavorable anatomic features for recanalization of the native coronary artery. In the first case, two dedicated attempts for recanalization of chronic total occlusion of the native artery failed and in the second case there was not an adequate visualization of the native vessel beyond the occlusion point, not even by contralateral injection. Excimer laser atherectomy was used in both cases as an adjuvant therapy during recanalization of the saphenous vein graft in combination with a distal protection device in order to reduce distal embolization. The procedures proved successful after stent implantation in the whole length of the saphenous vein grafts and the patients suffered no remarkable events during hospitalization.
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http://dx.doi.org/10.1016/j.carrev.2016.12.016DOI Listing
September 2017

Intravitreal bevacizumab for diabetic macular oedema: 5-year results of the Pan-American Collaborative Retina Study group.

Br J Ophthalmol 2016 Dec 24;100(12):1605-1610. Epub 2016 Feb 24.

Retina Service, Fundación Hospital Nuestra Señora de la Luz, Mexico City, Mexico.

Background/aims: To report the long-term anatomical and functional outcomes of patients with centre-involved diabetic macular oedema (DME) treated with intravitreal bevacizumab (IVB).

Methods: Retrospective case series. Patients diagnosed with centre-involved DME that were treated with at least one injection of 1.25 mg IVB and had a minimum follow-up of 60 months. Patients underwent measurement of best-corrected visual acuity (BCVA), ophthalmoscopy, optical coherence tomography and fluorescein angiography at baseline, 6-month, 12-month, 24-month, 36-month, 48-month and 60-month visits. The paired samples t test was used to compare the central macular thickness (CMT) and BCVA with baseline values. Statistical significance was indicated by p<0.05.

Results: Two hundred and one consecutive patients (296 eyes) were included. The mean number of IVB injections per eye was 8.4±7.1 (range: 1-47 injections). At 5 years, the BCVA remained stable at 20/100 (logarithm of the minimum angle of resolution=0.7±0.4). Eighty-six (29%) eyes improved ≥2 lines of BCVA, 129 (43.6%) eyes remained stable and 81 (27.4%) eyes lost ≥2 lines of BCVA at 60 months. Mean CMT decreased from 403.5±142.2 μm at baseline to 313.7±117.7 μm over 5 years follow-up (p≤0.0001).

Conclusions: The early visual gains due to IVB were not maintained 5 years after treatment.
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http://dx.doi.org/10.1136/bjophthalmol-2015-307950DOI Listing
December 2016

INTRAVITREAL BEVACIZUMAB FOR CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION: 5-Year Results of The Pan-American Collaborative Retina Study Group.

Retina 2016 May;36(5):859-67

*Retina Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD; †The Vitreoretinal and Uveitis Division, King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia; ‡The Retina and Vitreous Service, Clínica Privada de Ojos, Mar del Plata, Argentina; § Instituto de Cirugia Ocular, San Jose, Costa Rica; ¶University of Puerto Rico, San Juan, Puerto Rico; **Hospital La Fe, Universidad de Valencia, Spain; ††Clinica Oftalmologica Centro Caracas and the Arevalo-Coutinho Foundation for Research in Ophthalmology, Caracas, Venezuela; ‡‡OFTALMOS, Universidad de Buenos Aires, Facultad de Medicina, Buenos Aires, Argentina; §§Fundación Hospital Nuestra Señora de la Luz, Mexico City, Mexico; ¶¶Retina Division, Department of Ophthalmology and Visual Sciences, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil; and ***MACULA D&T Diagnóstico, Tratamiento & Rehabilitación Visual, Lima, Peru.

Purpose: To report the long-term anatomical and functional outcomes of patients with choroidal neovascularization secondary to age-related macular degeneration treated with intravitreal bevacizumab (IVB).

Methods: Retrospective case series. Patients diagnosed with subfoveal choroidal neovascularization secondary to age-related macular degeneration that were treated with at least 1 intravitreal injection of 1.25 mg of IVB and had a minimum follow-up of 60 months. Patients underwent best-corrected Snellen visual acuity testing, optical coherence tomography, and ophthalmoscopic examination at baseline and follow-up visits.

Results: Two hundred and forty-seven consecutive patients (292 eyes) were included. The mean number of IVB injections per eye was 10.9 ± 6.4. At 5 years, the BCVA decreased from 20/150 (logMAR 0.9 ± 0.6) at baseline to 20/250 (logMAR 1.1 ± 0.7) (P = <0.0001). The mean CMT decreased from 343.1+ 122.3 μm at baseline to 314.7 ± 128.8 μm at 60 months of follow-up (P = 0.009). Geographic atrophy (GA) was observed at baseline in 47 (16%) of 292 eyes. By 5 years, GA developed or progressed in 124 (42.5%) of 292 eyes (P < 0.0001).

Conclusion: The early visual gains obtained from IVB were not maintained at 5 years of follow-up. In addition, IVB may play a role in the development or progression of GA.
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http://dx.doi.org/10.1097/IAE.0000000000000827DOI Listing
May 2016

Tension gastrothorax mimicking acute coronary syndrome and causing cardiac arrest.

Eur Heart J 2014 Mar 29;35(12):794. Epub 2013 Aug 29.

Department of Critical Care Medicine, Hospital Universitari Joan XXIII de Tarragona, c/Dr. Mallafre Guasch 4, Tarragona 43007, Spain.

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http://dx.doi.org/10.1093/eurheartj/eht336DOI Listing
March 2014

Radical vaginal trachelectomy and laparoscopic pelvic lymphadenectomy in IB1 cervical cancer during pregnancy.

Gynecol Oncol Case Rep 2012 9;2(3):78-9. Epub 2012 Apr 9.

Oncologic Gynecology Unit, Van Buren Hospital, Valparaíso, Chile ; Oncologic Gynecology Unit, Gustavo Fricke Hospital, Viña del Mar, Chile ; Department of Gynecology and Obstetrics, University of Valparaíso, School of Medicine, Valparaíso, Chile.

► We expose an novel surgical technique in pregnant women with cervical cancer. ► We preserve the pregnancy in this case. ► After 40 months of monitoring both patient and her child are healthy.
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http://dx.doi.org/10.1016/j.gynor.2012.04.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3861275PMC
December 2013

Insights into the effects of functional groups on carbon nanotubes for the electrooxidation of methanol.

Langmuir 2011 Aug 8;27(15):9621-9. Epub 2011 Jul 8.

Dpto. Química-Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid (UAM), C/Francisco Tomás y Valiente 7, 28049 Madrid, Spain.

Functionalized carbon nanotubes were used as a support for PtCo nanoparticles. Their performance as electrocatalysts for the electrooxidation of methanol was evaluated by cyclic voltammetry and in situ FTIR reflectance spectroscopy. The onset potentials for both the electrooxidation of methanol and the production of CO(2) shifted to less positive values for catalysts prepared with more oxygen groups on the support. Furthermore, the production of CO(2) was higher on catalysts prepared with functionalized carbon nanotubes. The functional groups play two different but complementary roles. On the one hand, they help to stabilize smaller PtCo particles of ca. 3 nm. On the other hand, they provide the -OH groups necessary for the total oxidation of methanol to CO(2) at potentials less positive than on nonfunctionalized supports. Remarkably, the consumption of carboxylic acid groups along with the production of water is observed in the infrared spectra of the functionalized supports recorded during the electrooxidation of methanol. This observation suggests that the -OH groups of the support can also react with methanol, forming water and an ester.
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http://dx.doi.org/10.1021/la2011452DOI Listing
August 2011

Characterization of trimetallic Pt-Pd-Au/CeO2 catalysts combinatorial designed for methane total oxidation.

Comb Chem High Throughput Screen 2007 Jan;10(1):71-82

Institute of Surface Chemistry and Catalysis, Chemical Research Center, Hungarian Academy of Sciences, 1525 Budapest, P.O. Box 17, Hungary.

In the present work, the role and the effect of platinum and gold on the catalytic performance of ceria supported tri-metallic Pt-Pd-Au catalysts have been studied. The optimum composition of these tri-metallic supported catalysts has been discovered using methods and tools of combinatorial catalyst library design. Detailed catalytic, spectroscopic and physico-chemical characterization of catalysts in the vicinity of the optimum in the given compositional space has been performed. The temperature-programmed oxidation of methane revealed that the addition of Pt and Au to Pd/CeO2 catalyst resulted in higher conversion values in the whole investigated temperature range compared to the monometallic Pd catalyst. The time-on-stream experiments provided further evidence for the high-stability of tri-metallic catalysts compared to the monometallic one. Kinetic studies revealed the stronger adsorption of methane on Pt-Pd/CeO2 catalysts than over Pd/CeO2. XPS analysis showed that Pt and Au stabilize Pd in a more reduced form even under condition of methane oxidation. FTIR spectroscopy of adsorbed CO and hydrogen TPD measurements provided indirect evidences for alloying of Pt and Au with Pd. CO chemisorption data indicated that tri-metallic catalysts have increased accessible metallic surface area. It is suggested that advantageous catalytic properties of tri-metallic Pt-Au-Pd/CeO2 catalysts compared to the monometallic one can be attributed to (i) suppression of the formation of ionic forms of Pd(II), (ii) reaching an optimum ratio between Pd0 and PdO species, and (iii) stabilization of Pd in high dispersion. The results also indicate that Pd0 - PdO ensemble sites are required for methane activation.
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http://dx.doi.org/10.2174/138620707779802841DOI Listing
January 2007