231 research outputs found

    Report of the Coding Committee of the Association for European Paediatric Cardiology

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    IN 1999 AND EARLY 2000, THE ASSOCIATION FOR European Paediatric Cardiology published the European Paediatric Cardiac Code as independent but linked Short and Long Lists, containing 650 and 3876 primary terms respectively. The historical background and rationale for development of this coding system has been previously detailed, but essentially it followed a series of meeting of the coding committee of the Association between 1997-1999, during which a pre-existing Long List was adopted and then used to create the condensed Short List. The system was published as the recommended standard coding system for use across Europe, covering the diagnosis and therapy of children with congenital and acquired cardiac disease. The scope of the lists was to encompass the needs of all those involved with such patients, from the fetal cardiologist through to the specialist in adult congenital heart disease; and from the general paediatric cardiologist and cardiac surgeon, to those specialising in transcatheter interventions, paediatric electrophysiology, and paediatric echocardiographers. In addition, the code was crossmapped to the 9th and 10th revisions of the International Classification of Diseases ("ICD-9” and "ICD-10”) provided by the World Health Organisation in order to facilitate returns to central government, a requirement in most countries. In so doing, it was hoped to address the concerns of many centres that such information submitted by professional coding staff was often inaccurate due to the complex nature of congenital cardiac disease, together with the limited scope and vague terminology of the International listing

    Synthesis of reaction-adapted zeolites as methanol-to-olefins catalysts with mimics of reaction intermediates as organic structure-directing agents

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    [EN] Catalysis with enzymes and zeolites have in common the presence of well-defined single active sites and pockets/cavities where the reaction transition states can be stabilized by longer-range interactions. We show here that for a complex reaction, such as the conversion of methanol-to-olefins (MTO), it is possible to synthesize reaction-adapted zeolites by using mimics of the key molecular species involved in the MTO mechanism. Effort has focused on the intermediates of the paring mechanism because the paring is less favoured energetically than the side-chain route. All the organic structure-directing agents based on intermediate mimics crystallize cage-based small-pore zeolitic materials, all of them capable of performing the MTO reaction. Among the zeolites obtained, RTH favours the whole reaction steps following the paring route and gives the highest propylene/ethylene ratio compared to traditional CHA-related zeolites (3.07 and 0.86, respectively).Li, C.; Paris, C.; Martínez-Triguero, J.; Boronat Zaragoza, M.; Moliner Marin, M.; Corma Canós, A. (2018). Synthesis of reaction-adapted zeolites as methanol-to-olefins catalysts with mimics of reaction intermediates as organic structure-directing agents. Nature Catalysis. 1(7):547-554. https://doi.org/10.1038/s41929-018-0104-7S54755417Stocker, M. Methanol-to-hydrocarbons: catalytic materials and their behavior. Micro. Mesopor. Mater. 29, 3–48 (1999).Tian, P., Wei, Y., Ye, M. & Liu, Z. Methanol to olefins (MTO): from fundamentals to commercialization. ACS Catal. 5, 1922–1938 (2015).Ilias, S. & Bhan, A. Mechanism of the catalytic conversion of methanol to hydrocarbons. ACS Catal. 3, 18–31 (2013).Olsbye, U. et al. Conversion of methanol to hydrocarbons: how zeolite cavity and pore size controls product selectivity. Angew. Chem. Int. Ed. 24, 5810–5831 (2012).Hemelsoet, K., Van der Mynsbrugge, J., De Wispelaere, K., Waroquier, M. & Van Speybroeck, V. Unraveling the reaction mechanisms governing methanol-to-olefins catalysis by theory and experiment. ChemPhysChem 14, 1526–1545 (2013).Song, W., Haw, J. F., Nicholas, J. B. & Heneghan, C. S. Methylbenzenes are the organic reaction centers for methanol-to-olefin catalysis on HSAPO-34. J. Am. Chem. Soc. 122, 10726–10727 (2000).Arstad, B. & Kolboe, S. The reactivity of molecules trapped within the SAPO-34 cavities in the methanol-to-hydrocarbons reaction. J. Am. Chem. Soc. 123, 8137–8138 (2001).Xu, T. et al. Synthesis of a benzenium ion in a zeolite with use of a catalytic flow reactor. J. Am. Chem. Soc. 120, 4025–4026 (1998).Song, W., Nicholas, J. B., Sassi, A. & Haw, J. F. Synthesis of the heptamethylbenzene cation in zeolite beta: in situ NMR and theory. Catal. Lett. 81, 49–53 (2002).Xu, S. et al. Direct observation of cyclic carbenium ions and their role in the catalytic cycle of the metahnol-to-olefin reaction over chabazite zeolites. Angew. Chem. Int. Ed. 52, 11564–11568 (2013).Chen, J. et al. Elucidating the olefin formation mechanism in the methanol to olefin reaction over AlPO-18 and SAPO-18. Catal. Sci. Tech. 4, 3268–3277 (2014).Haw, J. F. et al. Roles for cyclopentenyl cations in the synthesis of hydrocarbons from methanol on zeolite catalyst HZSM-5. J. Am. Chem. Soc. 122, 4763–4775 (2000).Svelle, S. et al. Conversion of methanol into hydrocarbons over zeolite H-ZSM-5: ethene formation is mechanistically separated from the formation of higher alkenes. J. Am. Chem. Soc. 128, 14770–14771 (2006).Teketel, S., Olsbye, U., Lillerud, K. P., Beato, P. & S., S. Selectivity control through fundamental mechanistic insight in the conversion of methanol to hydrocarbons over zeolites. Micro. Mesopor. Mater. 136, 33–41 (2010).Zhang, M. et al. Methanol conversion on ZSM-22, ZSM-35 and ZSM-5 zeolites: effects of 10-membered ring zeolite structures on methylcyclopentenyl cations and dual cycle mechanism. RSC Adv. 6, 95855–95864 (2016).Sassi, A. et al. Methylbenzene chemistry on zeolite HBeta: multiple insights into methanol-to-olefin catalysis. J. Phys. Chem. B 106, 2294–2303 (2002).Sassi, A., Wildman, M. A. & Haw, J. F. Reactions of butylbenzene isomers on zeolite HBeta: methanol-to-olefins hydrocarbon pool chemistry and secondary reactions of olefins. J. Phys. Chem. B 106, 8768–8773 (2002).Bjørgen, M., Olsbye, U., Petersen, D. & Kolboe, S. The methanol-to-hydrocarbons reaction: insight into the reaction mechanism from [12C]benzene and [13C]methanol coreactions over zeolite H-beta. J. Catal. 221, 1–10 (2004).McCann, D. M. et al. A complete catalytic cycle for supramolecular methanol-to-olefins conversion by linking theory with experiment. Angew. Chem. Int. Ed. 47, 5179–5182 (2008).Arstad, B., Kolboe, S. & Swang, O. Theoretical study of the heptamethylbenzenium ion. intramolecular isomerizations and C2, C3, C4 alkene elimination. J. Phys. Chem. A 109, 8914–8922 (2005).De Wispelaere, K., Hemelsoet, K., Waroquier, M. & Van Speybroeck, V. Complete low-barrier side-chain route for olefin formation during methanol conversion in H-SAPO-34. J. Catal. 305, 76–80 (2013).Wang, C. M., Wang, Y. D. & Xie, Z. K. Verification of the dual cycle mechanism for methanol-to-olefin conversion in HSAPO-34: a methylbenzene-based cycle from DFT calculations. Catal. Sci. Technol. 4, 2631–2638 (2014).Wang, C. M., Wang, Y. D., Liu, H. X., Xie, Z. K. & Liu, Z. P. Theoretical insight into the minor role of paring mechanism in the methanol-to-olefins conversion within HSAPO-34 catalyst. Micro. Mesopor. Mater. 158, 264–271 (2012).Ilias, S. & Bhan, A. The mechanism of aromatic dealkylation in methanol-to-hydrocarbons conversion on H-ZSM-5: What are the aromatic precursors to light olefins? J. Catal. 311, 6–16 (2014).Erichsen, M. W. et al. Conclusive evidence for two unimolecular pathways to zeolite-catalyzed de-alkylation of the heptamethylbenzenium cation. ChemCatChem 7, 4143–4147 (2015).Bhawe, Y. et al. Effect of cage size on the selective conversion of methanol to light olefins. ACS Catal. 2, 2490–2495 (2012).Kang, J. H. et al. Further studies on how the nature of zeolite cavities that are bounded by small pores influences the conversion of methanol to light olefins. ChemPhysChem 19, 412–419 (2018).Martin, N. et al. Nanocrystalline SSZ-39 zeolite as an efficient catalyst for the methanol-to-olefin (MTO) process. Chem. Commun. 52, 6072–6075 (2016).Dusselier, M., Deimund, M. A., Schmidt, J. E. & Davis, M. E. Methanol-to-olefins catalysis with hydrothermally treated zeolite SSZ-39. 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I. Zeolite SSZ-13 and its method of preparation. US Patent 4,544,538 (1985).Li, Z., Navarro, M. T., Martínez-Triguero, J., Yu, J. & Corma, A. Synthesis of nano-SSZ-13 and its application in the reaction of methanol to olefins. Catal. Sci. Technol. 6, 5856–5863 (2016).Kumar, M., Luo, H., Román-Leshkov, Y. & Rimer, J. D. SSZ-13 crystallization by particle attachment and deterministic pathways to crystal size control. J. Am. Chem. Soc. 137, 13007–13017 (2015).Martínez-Franco, R., Cantin, A., Moliner, M. & Corma, A. Synthesis of the small pore silicoaluminophosphate STA-6 by using supramolecular self-assembled organic structure directing agents. Chem. Mater. 26, 4346–4353 (2014).Schmidt, J. E., Deimund, M. A., Xie, D. & Davis, M. E. Synthesis of RTH-type zeolites using a diverse library of imidazolium cations. Chem. Mater. 27, 3756–3762 (2015).Moliner, M., Franch, C., Palomares, E., Grill, M. & Corma, A. 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(Gaussian, Wallingford, 2009).Van Speybroeck, V. et al. First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev. 43, 7326–7357 (2014)

    Polymorphisms in transcription factor binding sites and enhancer regions and pancreatic ductal adenocarcinoma risk

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    Genome-wide association studies (GWAS) are a powerful tool for detecting variants associated with complex traits and can help risk stratification and prevention strategies against pancreatic ductal adenocarcinoma (PDAC). However, the strict significance threshold commonly used makes it likely that many true risk loci are missed. Functional annotation of GWAS polymorphisms is a proven strategy to identify additional risk loci. We aimed to investigate single-nucleotide polymorphisms (SNP) in regulatory regions [transcription factor binding sites (TFBSs) and enhancers] that could change the expression profile of multiple genes they act upon and thereby modify PDAC risk. We analyzed a total of 12,636 PDAC cases and 43,443 controls from PanScan/PanC4 and the East Asian GWAS (discovery populations), and the PANDoRA consortium (replication population). We identified four associations that reached study-wide statistical significance in the overall meta-analysis: rs2472632(A) (enhancer variant, OR 1.10, 95%CI 1.06,1.13, p = 5.5 × 10−8), rs17358295(G) (enhancer variant, OR 1.16, 95%CI 1.10,1.22, p = 6.1 × 10−7), rs2232079(T) (TFBS variant, OR 0.88, 95%CI 0.83,0.93, p = 6.4 × 10−6) and rs10025845(A) (TFBS variant, OR 1.88, 95%CI 1.50,1.12, p = 1.32 × 10−5). The SNP with the most significant association, rs2472632, is located in an enhancer predicted to target the coiled-coil domain containing 34 oncogene. Our results provide new insights into genetic risk factors for PDAC by a focused analysis of polymorphisms in regulatory regions and demonstrating the usefulness of functional prioritization to identify loci associated with PDAC risk.</p

    Polymorphisms in transcription factor binding sites and enhancer regions and pancreatic ductal adenocarcinoma risk

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    Genome-wide association studies (GWAS) are a powerful tool for detecting variants associated with complex traits and can help risk stratification and prevention strategies against pancreatic ductal adenocarcinoma (PDAC). However, the strict significance threshold commonly used makes it likely that many true risk loci are missed. Functional annotation of GWAS polymorphisms is a proven strategy to identify additional risk loci. We aimed to investigate single-nucleotide polymorphisms (SNP) in regulatory regions [transcription factor binding sites (TFBSs) and enhancers] that could change the expression profile of multiple genes they act upon and thereby modify PDAC risk. We analyzed a total of 12,636 PDAC cases and 43,443 controls from PanScan/PanC4 and the East Asian GWAS (discovery populations), and the PANDoRA consortium (replication population). We identified four associations that reached study-wide statistical significance in the overall meta-analysis: rs2472632(A) (enhancer variant, OR 1.10, 95%CI 1.06,1.13, p = 5.5 × 10−8), rs17358295(G) (enhancer variant, OR 1.16, 95%CI 1.10,1.22, p = 6.1 × 10−7), rs2232079(T) (TFBS variant, OR 0.88, 95%CI 0.83,0.93, p = 6.4 × 10−6) and rs10025845(A) (TFBS variant, OR 1.88, 95%CI 1.50,1.12, p = 1.32 × 10−5). The SNP with the most significant association, rs2472632, is located in an enhancer predicted to target the coiled-coil domain containing 34 oncogene. Our results provide new insights into genetic risk factors for PDAC by a focused analysis of polymorphisms in regulatory regions and demonstrating the usefulness of functional prioritization to identify loci associated with PDAC risk.</p

    Low-Energy Physics in Neutrino LArTPCs

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    In this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways
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