Background-Percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is superior tofibrinolysis when performed in a timely manner in high-volume centers. Recent European trials suggest that transfer for PCI also may be superior to fibrinolysis and increase access to PCI. In the United States, transfer times are consistently long; therefore, many believe a transfer for PCI strategy for STEMI is not practical.
Methods and Results-We
Artificial photosynthesis relies on the availability of semiconductors that are chemically stable and can efficiently capture solar energy. Although metal oxide semiconductors have been investigated for their promise to resist oxidative attack, materials in this class can suffer from chemical and photochemical instability. Here we present a methodology for evaluating corrosion mechanisms and apply it to bismuth vanadate, a state-of-the-art photoanode. Analysis of changing morphology and composition under solar water splitting conditions reveals chemical instabilities that are not predicted from thermodynamic considerations of stable solid oxide phases, as represented by the Pourbaix diagram for the system. Computational modelling indicates that photoexcited charge carriers accumulated at the surface destabilize the lattice, and that self-passivation by formation of a chemically stable surface phase is kinetically hindered. Although chemical stability of metal oxides cannot be assumed, insight into corrosion mechanisms aids development of protection strategies and discovery of semiconductors with improved stability.
ESPITE ITS LIMITATIONS, THEstandard 12-lead electrocardiogram (ECG) remains a key diagnostic tool directing the emergency management of patients with an acute myocardial infarction. 1 In 1980, DeWood et al 2 reported that patients presenting with acute chest pain, persistent ST-segment elevation progressing to Q waves, and elevations of cardiac biomarker levels were found to have a total thrombotic coronary occlusion in 87% of cases. A variety of other serious conditions aside from an acute myocardial infarction may also cause ST-segment elevation. 3 Time to reperfusion is a major determinant of outcome in patients presenting with an ST-segment elevation myocardial infarction (STEMI). 4,5 The American College of Cardiology/ American Heart Association STEMI guidelines recommend that the emergency department physician make the decision regarding reperfusion therapy within 10 minutes of interpreting the initial diagnostic ECG, 6 which may be challenging because clinical decisions are often made without a previous ECG result for comparison or time to observe evolutionary ST-segment changes or cardiac biomarker results. Upstream activation of the cardiac cath-For editorial comment see p 2790.
The limited selectivity
of existing CO2 reduction catalysts
and rising levels of CO2 in the atmosphere necessitate
the identification of specific structure–reactivity relationships
to inform catalyst development. Herein, we develop a predictive framework
to tune the selectivity of CO2 reduction on Cu by examining
a series of polymeric and molecular modifiers. We find that protic
species enhance selectivity for H2, hydrophilic species
enhance formic acid formation, and cationic hydrophobic species enhance
CO selectivity. ReaxFF reactive molecular dynamics simulations indicate
that the hydrophilic/hydrophobic modifiers influence the formation
of surface hydrides, which yield formic acid or H2. These
observations offer insights into how these modifiers influence catalytic
behavior at the non-precious Cu surface and may aid in the future
implementation of organic structures in CO2 reduction devices.
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