Net heterotrophy and carbonate dissolution in two subtropical seagrass meadows

The net ecosystem productivity (NEP) of two seagrass meadows within one of the largest seagrass ecosystems in the world, Florida Bay, was assessed using direct measurements over consecutive diel cycles during a short study in the fall of 2018. We report significant differences between NEP determined by dissolved inorganic carbon (NEPDIC) and by dissolved oxygen (NEPDO), likely driven by differences in air–water gas exchange and contrasting responses to variations in light intensity. We also acknowledge the impact of advective exchange on metabolic calculations of NEP and net ecosystem calcification (NEC) using the “open-water” approach and attempt to quantify this effect. In this first direct determination of NEPDIC in seagrass, we found that both seagrass ecosystems were net heterotrophic, on average, despite large differences in seagrass net above-ground primary productivity. NEC was also negative, indicating that both sites were net dissolving carbonate minerals. We suggest that a combination of carbonate dissolution and respiration in sediments exceeded seagrass primary production and calcification, supporting our negative NEP and NEC measurements. However, given the limited spatial (two sites) and temporal (8 d) extent of this study, our results may not be representative of Florida Bay as a whole and may be season-specific. The results of this study highlight the need for better temporal resolution, accurate carbonate chemistry accounting, and an improved understanding of physical mixing processes in future seagrass metabolism studies

The Influence of the Support Nature and the Metal Precursor in the Activity of Pd-based Catalysts for the Bromate Reduction Reaction

This is the peer reviewed version of the following article: J. L. Cerrillo, C. W. Lopes, F. Rey, A. E. Palomares, ChemCatChem 2021, 13, 1230, which has been published in final form at https://doi.org/10.1002/cctc.202001797. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Palladium catalysts supported on different materials (alumina, activated carbon and mixed oxide derived from hydrotalcite) and prepared with different metal precursors (nitrate, chloride and acetate) have been characterized and tested for the bromate reduction reaction. The catalytic behavior depends on the support nature and on the metallic precursor used for the catalyst preparation. Pd catalyst supported on a mixed oxide has a low activity due to the high affinity of the reconstructed support for the Br- formed, preventing the reactants to approximate the active Pd sites. Pd catalyst supported on activated carbon has a surface negative charge and a microporous structure, making difficult the interaction of the active sites with the reactants. The best results are obtained with the catalyst supported on alumina due to its physical-chemical properties, i. e. mesoporosity, positive surface charge and reversible adsorption of reactants and products. These characteristics make easy bromate and H-2 adsorption on the active sites and subsequent reaction, thus resulting in a better activity. The Pd precursor salt also influences the catalytic activity as it has an effect on the Pd nanocrystal size. The best results are obtained with the metal precursor that produces homogeneous and large Pd metallic crystallites.Authors thank the Spanish Ministry of Economy and Competitiveness through RTI2018-101784-B-I00 (MINECO/FEDER) and SEV2016-0683 projects for the financial support. We gratefully acknowledge ALBA synchrotron for allocating beamtime and CLAESS beamline staff for their technical support during our experiment. C.W. Lopes (Science without Frontiers -Process no. 13191/13-6) thanks CAPES for a predoctoral fellowship. J.L. Cerrillo is grateful to MINECO for the Severo Ochoa contract for PhD formation (SVP-2014-068600).The authors also wish to thank Elena Crespo and Adrian Pla for their collaboration in the experimental part of the paper.Cerrillo, JL.; Lopes, CW.; Rey Garcia, F.; Palomares Gimeno, AE. (2021). The Influence of the Support Nature and the Metal Precursor in the Activity of Pd-based Catalysts for the Bromate Reduction Reaction. ChemCatChem. 13(4):1230-1238. https://doi.org/10.1002/cctc.202001797S1230123813

AgY zeolite as catalyst for the selective catalytic oxidation of NH3

[EN] Ag-exchanged Y zeolites (Si/Al = 2.5; Ag/Al = 0.30-0.95) have been tested in the NH3-SCO reaction, the most promising method for the elimination of ammonia emissions, and deeply characterized before and after reaction by using a variety of techniques (XRD, TEM, UV-Vis, Ag-109 NMR, XAS spectroscopies). The most active centres for the NH3-SCO reaction are Ag-0 nanoparticles (NPs) formed under reduction conditions and both activity and selectivity to N-2 increase with the silver loading. The Ag-0 NPs are dramatically modified under reaction conditions, being most of them dispersed resulting in small clusters and even atomically Ag+ cations, the latter accounting for around half silver atoms. The presence of water into the reaction feed promotes the dispersion and oxidation of silver nanoparticles, but the catalyst performance is only slightly affected. The results are fully consistent with the previously proposed i-SCR mechanism for NH3-SCO reaction on silver catalysts.Financial support by the Ministerio de Ciencia e Innovacion (MICINN) of Spain through the Severo Ochoa (SEV-2016-0683) , RTI2018-101784-B-I00, RTI2018-09639-A-I00 and InnovaXN-26-2019 projects is gratefully acknowledged. The authors also thank the Microscopy Service of the Universitat Politecnica de Valencia for its assistance in microscopy characterization (TEM and FESEM equipment preparation) . C. W. Lopes (Science without Borders Process no. 13191/13-6) thanks CAPES for a predoctoral fellowship and J. Martinez-Ortigosa (SEV-2012-0267-02) is grateful to Severo Ochoa Program for a predoctoral fellowship. The authors also want to thank the ALBA synchrotron and CL AE SS beamline staff for providing beamtime (proposal 2017092477) and for setting the beamline up to perform these studies.Martinez-Ortigosa, J.; Lopes, CW.; Agostini, G.; Palomares Gimeno, AE.; Blasco Lanzuela, T.; Rey Garcia, F. (2021). AgY zeolite as catalyst for the selective catalytic oxidation of NH3. Microporous and Mesoporous Materials. 323:1-14. https://doi.org/10.1016/j.micromeso.2021.111230S11432

Nature and evolution of Pd catalysts supported on activated carbon fibers during the catalytic reduction of bromate in water

[EN] Catalytic hydrogenation of bromate using Pd catalysts supported on activated carbon fibers is a smart solution to treat bromate polluted water. These catalysts have been analyzed by different techniques for an in-deep characterization of the active sites. The in situ X-ray absorption spectroscopy and the CO chemisorption studies showed that Pd-0 nanoparticles with different crystal sizes were generated on the support during hydrogen activation at 200 degrees C and that the PdHx-phase was formed during the cooling to room temperature. As PdHx species formed on Pd-0 nanoparticles are responsible for bromate reduction, the most active catalysts are those having Pd-0 nanoparticles with large crystal sizes, where PdHx species are easily formed. The catalysts are fully stable in succesive reaction runs. It has been also shown that bromate reduction rate depends on the bromate concentration and on the hydrogen partial pressure, with a pseudo-first reaction order towards both reactants.Authors thank the Spanish Ministry of Economy and Competitiveness through RTI2018-101784-B-I00 (MINECO/FEDER) and SEV-2016-0683 projects for the financial support. We gratefully acknowledge ALBA synchrotron for allocating beamtime (proposal 2015091414) and CLAESS beamline staff for their technical support during our experiment. C. W. Lopes (Science without Frontiers -Process no. 13191/13-6) thanks CAPES for a predoctoral fellowship. J. L. Cerrillo is grateful to MINECO for the Severo Ochoa contract for PhD formation (SVP-2014-068600). L. Kiwi-Minsker acknowledges financial support provided by Russian Science Foundation (project 15-19-20023). Authors also thank Kynol Europa GmbH for the supply of the activated carbon fibers.Cerrillo, JL.; Lopes, CW.; Rey Garcia, F.; Agostini, G.; Kiwi-Minsker, L.; Palomares Gimeno, AE. (2020). Nature and evolution of Pd catalysts supported on activated carbon fibers during the catalytic reduction of bromate in water. Catalysis Science & Technology. 10(11):3646-3653. https://doi.org/10.1039/d0cy00606hS364636531011Naushad, M., Khan, M. R., ALOthman, Z. A., AlSohaimi, I., Rodriguez-Reinoso, F., Turki, T. M., & Ali, R. (2015). Removal of BrO3 − from drinking water samples using newly developed agricultural waste-based activated carbon and its determination by ultra-performance liquid chromatography-mass spectrometry. Environmental Science and Pollution Research, 22(20), 15853-15865. doi:10.1007/s11356-015-4786-yBUTLER, R., GODLEY, A., LYTTON, L., & CARTMELL, E. (2005). Bromate Environmental Contamination: Review of Impact and Possible Treatment. 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Journal of Environmental Chemical Engineering, 7(3), 103015. doi:10.1016/j.jece.2019.103015Perez-Coronado, A. M., Soares, O. S. G. P., Calvo, L., Rodriguez, J. J., Gilarranz, M. A., & Pereira, M. F. R. (2018). Catalytic reduction of bromate over catalysts based on Pd nanoparticles synthesized via water-in-oil microemulsion. Applied Catalysis B: Environmental, 237, 206-213. doi:10.1016/j.apcatb.2018.05.077Li, M., Zhou, X., Sun, J., Fu, H., Qu, X., Xu, Z., & Zheng, S. (2019). Highly effective bromate reduction by liquid phase catalytic hydrogenation over Pd catalysts supported on core-shell structured magnetites: Impact of shell properties. Science of The Total Environment, 663, 673-685. doi:10.1016/j.scitotenv.2019.01.392Chen, X., Huo, X., Liu, J., Wang, Y., Werth, C. J., & Strathmann, T. J. (2017). Exploring beyond palladium: Catalytic reduction of aqueous oxyanion pollutants with alternative platinum group metals and new mechanistic implications. Chemical Engineering Journal, 313, 745-752. doi:10.1016/j.cej.2016.12.058Gao, Y., Sun, W., Yang, W., & Li, Q. (2017). Creation of Pd/Al2O3 Catalyst by a Spray Process for Fixed Bed Reactors and Its Effective Removal of Aqueous Bromate. Scientific Reports, 7(1). doi:10.1038/srep41797Li, M., Hu, Y., Fu, H., Qu, X., Xu, Z., & Zheng, S. (2019). Pt embedded in carbon rods of N-doped CMK-3 as a highly active and stable catalyst for catalytic hydrogenation reduction of bromate. Chemical Communications, 55(78), 11786-11789. doi:10.1039/c9cc05274gMarco, Y., García-Bordejé, E., Franch, C., Palomares, A. E., Yuranova, T., & Kiwi-Minsker, L. (2013). Bromate catalytic reduction in continuous mode using metal catalysts supported on monoliths coated with carbon nanofibers. Chemical Engineering Journal, 230, 605-611. doi:10.1016/j.cej.2013.06.040Yuranova, T., Kiwi-Minsker, L., Franch, C., Palomares, A. E., Armenise, S., & García-Bordejé, E. (2013). Nanostructured Catalysts for the Continuous Reduction of Nitrates and Bromates in Water. Industrial & Engineering Chemistry Research, 52(39), 13930-13937. doi:10.1021/ie302977hPalomares, A. E., Franch, C., & Corma, A. (2011). A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor. Catalysis Today, 172(1), 90-94. doi:10.1016/j.cattod.2011.05.015Yuranova, T., Franch, C., Palomares, A. E., Garcia-Bordejé, E., & Kiwi-Minsker, L. (2012). Structured fibrous carbon-based catalysts for continuous nitrate removal from natural water. Applied Catalysis B: Environmental, 123-124, 221-228. doi:10.1016/j.apcatb.2012.04.007Lan, H., Mao, R., Tong, Y., Liu, Y., Liu, H., An, X., & Liu, R. (2016). Enhanced Electroreductive Removal of Bromate by a Supported Pd–In Bimetallic Catalyst: Kinetics and Mechanism Investigation. Environmental Science & Technology, 50(21), 11872-11878. doi:10.1021/acs.est.6b02822Yao, F., Yang, Q., Yan, M., Li, X., Chen, F., Zhong, Y., … Li, X. (2020). Synergistic adsorption and electrocatalytic reduction of bromate by Pd/N-doped loofah sponge-derived biochar electrode. Journal of Hazardous Materials, 386, 121651. doi:10.1016/j.jhazmat.2019.121651Morais, D. F. S., Boaventura, R. A. R., Moreira, F. C., & Vilar, V. J. P. (2019). Advances in bromate reduction by heterogeneous photocatalysis: The use of a static mixer as photocatalyst support. Applied Catalysis B: Environmental, 249, 322-332. doi:10.1016/j.apcatb.2019.02.070Cunha, G. S., Santos, S. G. S., Souza-Chaves, B. M., Silva, T. F. C. V., Bassin, J. P., Dezotti, M. W. C., … Vilar, V. J. P. (2019). Removal of bromate from drinking water using a heterogeneous photocatalytic mili-reactor: impact of the reactor material and water matrix. Environmental Science and Pollution Research, 26(32), 33281-33293. doi:10.1007/s11356-019-06266-9Matatov-Meytal, Y., & Sheintuch, M. (2002). Catalytic fibers and cloths. Applied Catalysis A: General, 231(1-2), 1-16. doi:10.1016/s0926-860x(01)00963-2Joannet, E., Horny, C., Kiwi-Minsker, L., & Renken, A. (2002). Palladium supported on filamentous active carbon as effective catalyst for liquid-phase hydrogenation of 2-butyne-1,4-diol to 2-butene-1,4-diol. Chemical Engineering Science, 57(16), 3453-3460. doi:10.1016/s0009-2509(02)00215-4Crespo-Quesada, M., Dykeman, R. R., Laurenczy, G., Dyson, P. J., & Kiwi-Minsker, L. (2011). Supported nitrogen-modified Pd nanoparticles for the selective hydrogenation of 1-hexyne. Journal of Catalysis, 279(1), 66-74. doi:10.1016/j.jcat.2011.01.003Fang, W., Yang, S., Wang, X.-L., Yuan, T.-Q., & Sun, R.-C. (2017). Manufacture and application of lignin-based carbon fibers (LCFs) and lignin-based carbon nanofibers (LCNFs). 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Anderson , Structure of metallic catalysts , Academic Press , London-New York , 1918Martínez, A., Arribas, M. A., Derewinski, M., & Burkat-Dulak, A. (2010). Enhanced sulfur resistance of bifunctional Pd/HZSM-5 catalyst comprising hierarchical carbon-templated zeolite. Applied Catalysis A: General, 379(1-2), 188-197. doi:10.1016/j.apcata.2010.03.023Ravel, B., & Newville, M. (2005). ATHENA,ARTEMIS,HEPHAESTUS: data analysis for X-ray absorption spectroscopy usingIFEFFIT. Journal of Synchrotron Radiation, 12(4), 537-541. doi:10.1107/s0909049505012719Groppo, E., Agostini, G., Borfecchia, E., Wei, L., Giannici, F., Portale, G., … Lamberti, C. (2014). Formation and Growth of Pd Nanoparticles Inside a Highly Cross-Linked Polystyrene Support: Role of the Reducing Agent. The Journal of Physical Chemistry C, 118(16), 8406-8415. doi:10.1021/jp5003897Groppo, E., Liu, W., Zavorotynska, O., Agostini, G., Spoto, G., Bordiga, S., … Zecchina, A. (2010). Subnanometric Pd Particles Stabilized Inside Highly Cross-Linked Polymeric Supports. Chemistry of Materials, 22(7), 2297-2308. doi:10.1021/cm903176dBugaev, A. L., Guda, A. A., Lazzarini, A., Lomachenko, K. A., Groppo, E., Pellegrini, R., … Lamberti, C. (2017). In situ formation of hydrides and carbides in palladium catalyst: When XANES is better than EXAFS and XRD. Catalysis Today, 283, 119-126. doi:10.1016/j.cattod.2016.02.065Fernández-García, M. (2002). XANES analysis of catalytic systems under reaction conditions. Catalysis Reviews, 44(1), 59-121. doi:10.1081/cr-120001459Lopes, C. W., Cerrillo, J. L., Palomares, A. E., Rey, F., & Agostini, G. (2018). An in situ XAS study of the activation of precursor-dependent Pd nanoparticles. Physical Chemistry Chemical Physics, 20(18), 12700-12709. doi:10.1039/c8cp00517fWang, J., Wang, Q., Jiang, X., Liu, Z., Yang, W., & Frenkel, A. I. (2014). 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Cobalt nanoclusters coated with N-doped carbon for chemoselective nitroarene hydrogenation and tandem reactions in water

[EN] The development of active and selective non-noble metal-based catalysts for the chemoselective reduction of nitro compounds in aquo media under mild conditions is an attractive research area. Herein, the synthesis of subnanometric and stable cobalt nanoclusters, covered by N-doped carbon layers as core shell (CoaNC-800), for the chemoselective reduction of nitroarenes is reported. The Co@NC-800 catalyst was prepared by the pyrolysis of the Co(tpy)(2) complex impregnated on Vulcan carbon. In fact, the use of a molecular complex based on six N-Co bonds drives the formation of a well-defined and distributed cobalt core-shell nanocluster covered by N-doped carbon layers. In order to elucidate its nature, it has been fully characterized by using several advanced techniques. in addition, this as-prepared catalyst showed high activity, chemoselectivity and stability toward the reduction of nitro compounds with H-2 and under mild reaction conditions; water was used as a green solvent, improving the previous results based on cobalt catalysts. Moreover, the Co@NC-800 catalyst is also active and selective for the one-pot synthesis of secondary aryl amines and isoindolinones through the reductive amination of nitroarenes. Finally, based on diffraction and spectroscopic studies, metallic cobalt nanoclusters with surface CoNx patches have been proposed as the active phase in the Co@NC-800 material.The authors acknowledge the financial support from the Spanish Government (RTI2018-096399-A-I00) and the Program Severo Ochoa SEV-2016-0683. S. G. T. is thankful to MINECO for her FPU Ph.D. contract FPU16/02117. P. O.-B. is thankful to MICCIN for his Ramon y Cajal contract RYC-2014-16620 and to UPV for the grant PAID-06-18/SP20180172 The High-Resolution STEM data were recorded at the DME-UCA node of the ELECMI ICTS Spanish National Infrastructure for Electron Microscopy of Materials. JJC acknowledges financial support from MINECO/FEDER (Project MAT2017-97579-R). C. W. L. acknowledges the Visiting Researcher Fellowship from PRH 50.1 - ANP/FINEP Human Resources Program (Brazil).Gutiérrez-Tarriño, S.; Rojas-Buzo, S.; Lopes, CW.; Agostini, G.; Calvino, JJ.; Corma Canós, A.; Oña-Burgos, P. (2021). Cobalt nanoclusters coated with N-doped carbon for chemoselective nitroarene hydrogenation and tandem reactions in water. Green Chemistry. 23(12):4490-4501. https://doi.org/10.1039/d1gc00706h44904501231

Regioselective generation and reactivity control of subnanometric platinum clusters in zeolites for high-temperature catalysis

[EN] Subnanometric metal species (single atoms and clusters) have been demonstrated to be unique compared with their nanoparticulate counterparts. However, the poor stabilization of subnanometric metal species towards sintering at high temperature (>500 degrees C) under oxidative or reductive reaction conditions limits their catalytic application. Zeolites can serve as an ideal support to stabilize subnanometric metal catalysts, but it is challenging to localize subnanometric metal species on specific sites and modulate their reactivity. We have achieved a very high preference for localization of highly stable subnanometric Pt and PtSn clusters in the sinusoidal channels of purely siliceous MFI zeolite, as revealed by atomically resolved electron microscopy combining high-angle annular dark-field and integrated differential phase contrast imaging techniques. These catalysts show very high stability, selectivity and activity for the industrially important dehydrogenation of propane to form propylene. This stabilization strategy could be extended to other crystalline porous materials.This work has been supported by the European Union through the European Research Council (grant ERC-AdG-2014-671093, SynCatMatch) and the Spanish government through the Severo Ochoa Programme (SEV-2016-0683). L.L. thanks ITQ for providing a contract. The authors also thank the Microscopy Service of UPV for the TEM and STEM measurements. The XAS measurements were carried out in CLAESS beamline at the ALBA synchrotron. HR STEM measurements were performed at DME-UCA in Cadiz University with financial support from FEDER/MINECO (MAT2017-87579-R and MAT2016-81118-P). A relevant patent application (European patent application No. 19382024.8) has been presented. C.W.L. thanks CAPES (Science without Frontiers-Process no. 13191/13-6) for a predoctoral fellowship.Liu, L.; Lopez-Haro, M.; Lopes, CW.; Li, C.; Concepción Heydorn, P.; Simonelli, L.; Calvino, JJ.... (2019). Regioselective generation and reactivity control of subnanometric platinum clusters in zeolites for high-temperature catalysis. Nature Materials. 18(8):866-875. https://doi.org/10.1038/s41563-019-0412-6S86687518

MOF-mediated synthesis of supported Fe-doped Pd nanoparticles under mild conditions for magnetically recoverable catalysis

Metal-organic framework (MOF)-driven synthesis is considered as a promising alternative for the development of new catalytic materials with well-designed active sites. This synthetic approach is used here to gradually transform a new bimetallic MOF, with Pd and Fe as the metal components, by the in situ generation of aniline under mild conditions. This methodology results in a compositionally homogeneous nanocomposite formed by Fe-doped Pd nanoparticles that, in turn, are supported on iron oxide-doped carbon. The nanocomposite has been fully characterized by several techniques such as IR and Raman spectroscopy, TEM, XPS, and XAS. The performance of this nanocomposite as an heterogeneous catalyst for hydrogenation of nitroarenes and nitrobenzene coupling with benzaldehyde has been evaluated, proving it to be an efficient and reusable catalyst

Calcification-driven CO2emissions exceed blue Carbon sequestration in a carbonate seagrass meadow

Long-term Blue Carbon burial in seagrass meadows is complicated by other carbon and alkalinity exchanges that shape net carbon sequestration. We measured a suite of such processes, including denitrification, sulfur, and inorganic carbon cycling, and assessed their impact on air-water CO2 exchange in a typical seagrass meadow underlain by carbonate sediments. Eddy covariance measurements reveal a consistent source of CO2 to the atmosphere at an average rate of 610 ± 990 μmol m-2 hour-1 during our study and 700 ± 660 μmol m-2 hour-1 (6.1 mol m-2 year-1) over an annual cycle. Net alkalinity consumption by ecosystem calcification explains \u3e95% of the observed CO2 emissions, far exceeding organic carbon burial and anaerobic alkalinity generation. We argue that the net carbon sequestration potential of seagrass meadows may be overestimated if calcification-induced CO2 emissions are not accounted for, especially in regions where calcification rates exceed net primary production and burial

Efficacy and safety of cangrelor in patients with peripheral artery disease undergoing percutaneous coronary intervention – Insights from the CHAMPION program

Abstract Background Peripheral artery disease (PAD) is associated with an increased risk of ischemic events following percutaneous coronary intervention (PCI). More aggressive antiplatelet therapy may mitigate this risk. The present study evaluates the efficacy of cangrelor in patients with PAD undergoing PCI. Methods and results This is a pooled analysis from the CHAMPION PCI, CHAMPION PLATFORM, AND CHAMPION PHOENIX trials, evaluating cangrelor versus either clopidogrel or placebo in PCI patients. The occurrence of the primary endpoint of death, myocardial infarction, or ischemia-driven revascularization (IDR) was assessed in patients with and without PAD. GUSTO severe bleeding at 48 h was also evaluated. There were 1720 (7%) patients with PAD and 22,802 (93%) without PAD. After adjustment for differences in baseline variables, PAD patients, compared with those without PAD, experienced increased odds of the primary endpoint (OR [95% CI] = 1.27 [0.91, 1.77], P = 0.16) and GUSTO severe bleeding (OR [95% CI] = 3.24 [1.28, 8.21], P = 0.01). In PAD patients, the primary endpoint was 4.7% with cangrelor vs. 7.2% with clopidogrel (OR [95% CI] = 0.64 [0.42,0.96]); in patients without PAD the primary endpoint was 3.5% with cangrelor vs. 4.2% with clopidogrel (OR [95% CI] = 0.83 [0.72,0.95]), P-interaction 0.23. Among patients with or without PAD, there was no significant difference in the rate of GUSTO severe bleeding with cangrelor compared with control, P-interaction 0.86. Conclusions In a pooled analysis of the CHAMPION studies, PAD was associated with increased rates of ischemic and bleeding complications. Cangrelor reduced the odds of ischemic events, without increasing GUSTO severe bleeding. Clinical trial registration clinicaltrials.gov identifiers: CHAMPION PCI ( NCT00305162 ), CHAMPION PLATFORM ( NCT00385138 ), CHAMPION PHOENIX ( NCT01156571

Central Adjudication Identified Additional and Prognostically Important Myocardial Infarctions in Patients Undergoing Percutaneous Coronary Intervention

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