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1.
Angew Chem Int Ed Engl ; 62(49): e202310788, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-37811682

RESUMO

The need of carbon sources for the chemical industry, alternative to fossil sources, has pointed to CO2 as a possible feedstock. While CO2 electroreduction (CO2 R) allows production of interesting organic compounds, it suffers from large carbon losses, mainly due to carbonate formation. This is why, quite recently, tandem CO2 R, a two-step process, with first CO2 R to CO using a solid oxide electrolysis cell followed by CO electroreduction (COR), has been considered, since no carbon is lost as carbonate in either step. Here we report a novel copper-based catalyst, silver-doped copper nitride, with record selectivity for formation of propanol (Faradaic efficiency: 45 %), an industrially relevant compound, from CO electroreduction in gas-fed flow cells. Selective propanol formation occurs at metallic copper atoms derived from copper nitride and is promoted by silver doping as shown experimentally and computationally. In addition, the selectivity for C2+ liquid products (Faradaic efficiency: 80 %) is among the highest reported so far. These findings open new perspectives regarding the design of catalysts for production of C3 compounds from CO2 .

2.
ACS Appl Mater Interfaces ; 14(28): 31933-31941, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35802813

RESUMO

Gas-fed zero-gap electrolyzers have recently emerged as attractive systems for limiting ohmic losses and costs associated with electrolytes and for optimizing energy efficiencies. Here, we report that using a dendritic Cu oxide (D-CuO) material deposited on a gas diffusion layer as the cathode of a gas-fed zero-gap membrane electrode assembly (MEA) system results in a very selective conversion of CO to ethylene. More specifically, CO reduction yielded ethylene with an FE up to 68% at 100-125 mA·cm-2 with H2 as the only other gaseous product and the electrolysis could be carried out for several hours with good stability. Ethylene was also the major product during CO2 electrolysis (FE = 41%) at 125-150 mA·cm-2, reflecting the high selectivity of D-CuO for ethylene production. Such systems are relevant for tandem CO2 electroreduction processes, allowing energy efficiencies above 30%.

3.
Angew Chem Int Ed Engl ; 61(32): e202206279, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35678174

RESUMO

Electrochemical CO2 reduction presents a sustainable route to the production of chemicals and fuels. Achieving a narrow product distribution with heterogeneous Cu catalysts is challenging and conventional material modifications offer limited control over selectivity. Here, we show that surface-immobilised molecular species can act as inhibitors for specific carbon products to provide rational control over product distributions. Combined experimental and computational results showed that anchoring of a thiol-functionalised pyridine on Cu destabilises a surface-bound reaction intermediate to energetically block a CO-producing pathway, thereby favouring formate production. The nitrogen atom was shown to be essential to the inhibition mechanism. The ability of molecules to control selectivity through inhibition of specific reaction pathways offers a unique approach to rationally modify heterogeneous catalysts.

5.
Phys Chem Chem Phys ; 22(34): 18860-18867, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32211712

RESUMO

The discovery of novel catalytic materials is predicated on understanding contemporary synthetic processes. With this fundamental knowledge in place it becomes possible to modify the final material with subtle changes to the synthesis process. In this vein, hierarchical materials, formed by the addition of a mesoporogen within the hydrothermal synthesis, have attracted a significant amount of attention due to their catalytic benefits over analogous microporous species. In this work we monitor the hydrothermal synthesis in situ of a hierarchical and a microporous aluminophosphate, for the first time, combining total scattering and pairwise distribution function data. In doing so we observe the local formation of the species, and the longer range crystallisation processes concurrently.

6.
J Am Chem Soc ; 140(14): 4849-4859, 2018 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-29488757

RESUMO

The active sites for propane dehydrogenation in Ga/H-ZSM-5 with moderate concentrations of tetrahedral aluminum in the lattice were identified to be Lewis-Brønsted acid pairs. With increasing availability, Ga+ and Brønsted acid site concentrations changed inversely, as protons of Brønsted acid sites were exchanged with Ga+. At a Ga/Al ratio of 1/2, the rate of propane dehydrogenation was 2 orders of magnitude higher than with the parent H-ZSM-5, highlighting the extraordinary activity of the Lewis-Brønsted acid pairs. Density functional theory calculations relate the high activity to a bifunctional mechanism that proceeds via heterolytic activation of the propane C-H bond followed by a monomolecular elimination of H2 and desorption of propene.

7.
BMJ Open ; 6(2): e008322, 2016 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-26873042

RESUMO

OBJECTIVES: Patient safety is a crucial issue in medicine. Its main objective is to reduce the number of deaths and health damages that are caused by preventable medical errors. To achieve this, it needs better health systems that make mistakes less likely and their effects less detrimental without blaming health workers for failures. Until now, there is no in-depth scientometric analysis on this issue that encompasses the interval between 1963 and 2014. Therefore, the aim of this study is to sketch a landscape of the past global research output on patient safety including the gender distribution of the medical discipline of patient safety by interpreting scientometric parameters. Additionally, respective future trends are to be outlined. SETTING: The Core Collection of the scientific database Web of Science was searched for publications with the search term 'Patient Safety' as title word that was focused on the corresponding medical discipline. The resulting data set was analysed by using the methodology implemented by the platform NewQIS. To visualise the geographical landscape, state-of-the-art techniques including density-equalising map projections were applied. RESULTS: 4079 articles on patient safety were identified in the period from 1900 to 2014. Most articles were published in North America, the UK and Australia. In regard to the overall number of publications, the USA is the leading country, while the output ratio to the population of Switzerland was found to exhibit the best performance. With regard to the ratio of the number of publications to the Gross Domestic Product (GDP) per Capita, the USA remains the leading nation but countries like India and China with a low GDP and high population numbers are also profiting. CONCLUSIONS: Though the topic is a global matter, the scientific output on patient safety is centred mainly in industrialised countries.


Assuntos
Pesquisa Biomédica , Internacionalidade , Erros Médicos/prevenção & controle , Segurança do Paciente , Feminino , Humanos , Masculino , Distribuição por Sexo , Organização Mundial da Saúde
8.
Lung Cancer ; 60(3): 426-33, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18215438

RESUMO

Recent studies have challenged the previously postulated concept of a tumor-suppressive effect of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1). A possible angiogenic influence of CEACAM-1 in non-small-cell lung cancer (NSCLC) has not been investigated so far. Therefore, we examined microvessel density (MVD) and CEACAM-1 expression in primary NSCLC and analyzed their possible correlations under consideration of their prognostic effects. Specimens from 82 consecutive patients with completely resected NSCLC were stained immunohistochemically using the monoclonal anti-CEACAM-1 antibody 4D1/C2 and the monoclonal anti-CD31 antibody JC70A. The prognostic relevance of CEACAM-1 expression and MVD was evaluated by univariate Kaplan-Meier and multivariate Cox regression analysis. The median follow-up period was 75 months (range 10-156 months). A high MVD (i.e., > or =31microvessels/400x microscopic field) was observed more frequently in tumors with high CEACAM-1 expression (i.e., >/=66% stained tumor cells) than in tumors with low CEACAM-1 expression (61.8% vs. 33.3%, respectively; p=0.01). In univariate survival analyses, high CEACAM-1 expression and high MVD were associated with development of distant metastasis (p=0.011 and 0.022, respectively) and decreased cancer-related survival (p=0.046 and 0.006, respectively). Multivariate Cox regression analysis demonstrated that the prognostic impact of CEACAM-1 depended on the prognostic influence of MVD, while MVD itself represented an independent prognosticator for unfavorable cancer-related survival (p=0.021; relative risk 2.1; 95% confidence interval, 1.1-4.0). Here we show for the first time that high CEACAM-1 expression is associated with an increased angiogenic activity in NSCLC, and that the prognostic influence of CEACAM-1 might be derived from this association.


Assuntos
Antígenos CD/genética , Carcinoma Pulmonar de Células não Pequenas/irrigação sanguínea , Moléculas de Adesão Celular/genética , Neoplasias Pulmonares/irrigação sanguínea , Neovascularização Patológica/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/imunologia , Antígenos CD/biossíntese , Antígenos CD/imunologia , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Moléculas de Adesão Celular/biossíntese , Moléculas de Adesão Celular/imunologia , Feminino , Seguimentos , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neovascularização Patológica/imunologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/biossíntese , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Molécula-1 de Adesão Celular Endotelial a Plaquetas/imunologia , Prognóstico
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