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The chemical transformations that occur in metal oxides under operating conditions limit their applications for artificial photosynthesis. Understanding these chemical changes is a prerequisite to achieve sustainable production of solar fuels and chemicals. Herein, we use a correlative approach to unravel how cuprous oxide (Cu2O) photoelectrodes change under reaction conditions and, consequently, provide a protection scheme to mitigate degradation. In agreement with theoretical predictions, we find that under illumination the Cu2O concurrently undergoes reduction by photoelectrons and oxidation by holes in the material at electrolyte-dependent degradation rates. These mechanistic insights led us to design a protection scheme that uses a silver catalyst to accelerate transfer of photogenerated electrons and a Z-scheme heterojunction to extract holes. The resulting photocathode exhibits a stable photocurrent for CO2 reduction with ~60% Faradaic efficiency for ethylene with a balance of hydrogen for hours, whereas bare Cu2O degrades within minutes. Photoelectrodes for light-driven CO2 reduction to fuels and chemicals often suffer drastic decreases in performance due to changes in the material under illumination. Here the authors investigate the degradation pathways that occur in Cu2O photocathodes for ethylene synthesis and put forward strategies to mitigate them.

Electrochemical reduction of carbon dioxide (CO

Copper nitride (Cu3N)-based binary and ternary semiconductors have the potential to significantly impact photovoltaic and photoelectrochemical applications due to their ideal and tunable band gaps ...

Solar-driven reduction of carbon dioxide represents a carbon-neutral pathway for the synthesis of fuels and chemicals. We report here results for solar-driven CO2 reduction using a gas diffusion el...

Photoelectrochemical (PEC) water splitting, which utilizes sunlight and water to produce hydrogen fuel, is potentially one of the most sustainable routes to clean energy. One challenge to success is that, to date, similar materials and devices measured in different labs or by different operators lead to quantitatively different results, due to the lack of accepted standard operating procedures and established protocols for PEC efficiency testing. With the aim of disseminating good practices within the PEC community, we provide a vetted protocol that describes how to prepare integrated components and accurately measure their solar-to-hydrogen (STH) efficiency (ηSTH). This protocol provides details on electrode fabrication, ηSTH test device assembly, light source calibration, hydrogen evolution measurement, and initial material qualification by photocurrent measurements under monochromatic and broadband illumination. Common pitfalls in translating experimental results from any lab to an accurate STH efficiency under an AM1.5G reference spectrum are discussed. A III–V tandem photocathode is used to exemplify the process, though with small modifications, the protocol can be applied to photoanodes as well. Dissemination of PEC best practices will help those approaching the field and provide guidance for comparing the results obtained at different lab sites by different groups.

The limited selectivity of existing CO_2 reduction catalysts and rising levels of CO_2 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 CO_2 reduction on Cu by examining a series of polymeric and molecular modifiers. We find that protic species enhance selectivity for H_2, 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 H_2. 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 CO_2 reduction devices.

The rational design of high-performance electrocatalysts requires a detailed understanding of dynamic changes in catalyst properties, including oxidation states, surface area, and morphology under realistic working conditions. Oxide-derived Cu catalysts exhibit a remarkable selectivity towards multi-carbon products for the electrochemical CO reduction reaction (CORR), but the exact role of oxide remains elusive for explaining the performance enhancements. Here, we used operando X-ray absorption spectroscopy (XAS) coupled with simultaneous measurements of catalyst activity and selectivity by gas chromatography (GC) to study the relationship between oxidation states of Cu-based catalysts and activity for ethylene (C2H4) production in a CO gas-fed cell. By utilizing a custom-built XAS cell, oxidation states of Cu catalysts can be probed in device-relevant settings and under high current densities (>80 mA/cm-2) for CORR. By employing an electrochemical oxidation process, we found that the Cu oxidation states and specific ion species do not correlate with C2H4 production. The difference in CORR activity is also investigated in relation to the electrochemical surface area (ECSA) changes. While hydrogen evolution reaction (HER) activity is positively correlated to the ECSA changes, the increased C2H4 activity is not proportional to ECSA. Ex-situ characterization from microscopic techniques suggests that the changes in C2H4 activity and selectivity may arise from a morphological transformation that evolves into a more active structure. These comprehensive results give rise to the development of a cell regeneration method that can restore the performance of Cu catalyst without cell disassembly. Our study establishes a basis for the rational design of highly active electrocatalysts for broad-range reactions in a gas-fed device.

The activity of polycrystalline thin film photoelectrodes is impacted by local variations of the material properties due to the exposure of different crystal facets and the presence of grain/domain boundaries. Here a multi-modal approach is applied to correlate nanoscale heterogeneities in chemical composition and electronic structure with nanoscale morphology in polycrystalline Mo-BiVO

Conversion of CO

Confinement of metal centers is a powerful tool to manipulate reactivity and tune selectivity in chemical transformations. While aluminum as a foil is inactive for carbon dioxide reduction and shows high selectivity for the hydrogen evolution reaction, here we show that aluminum confined in a metal–organic framework (MOF), MIL-53(Al), suppresses hydrogen evolution reaction activity and enhances carbon dioxide reduction. This aluminum MOF can produce up to 40% faradaic efficiency for carbon monoxide and formic acid. This study demonstrates that the unique reaction environment created by the MOF enables changes in reaction selectivity and can impart atypical catalytic capabilities to metals.

Conversion of CO2 to reduced products is a promising route to alleviate irreversible climate change. Here we report the synthesis of a Co-based phthalocyanine with pyridine moieties (CoPc-Pyr), which is supported on a carbon electrode and shows Faradaic efficiency ∼90% for CO at 490 mV of overpotential (-0.6 V vs reversible hydrogen electrode (RHE)). In addition, its catalytic activity at -0.7 V versus RHE surpasses other Co-based molecular and metal-organic framework catalysts for CO2 reduction at this bias. Density functional theory calculations show that pyridine moieties enhance CO2 adsorption and electron affinity of the Co center by an inductive effect, thus lowering the overpotential necessary for CO2 conversion. Our study shows that CoPc-Pyr reduces CO2 at lower overpotential and with higher activity than noble metal electrodes, such as silver.

Indexación: Scopus. The activity of polycrystalline thin film photoelectrodes is impacted by local variations of the material properties due to the exposure of different crystal facets and the presence of grain/domain boundaries. Here a multi-modal approach is applied to correlate nanoscale heterogeneities in chemical composition and electronic structure with nanoscale morphology in polycrystalline Mo-BiVO4. By using scanning transmission X-ray microscopy, the characteristic structure of polycrystalline film is used to disentangle the different X-ray absorption spectra corresponding to grain centers and grain boundaries. Comparing both spectra reveals phase segregation of V2O5 at grain boundaries of Mo-BiVO4 thin films, which is further supported by X-ray photoelectron spectroscopy and many-body density functional theory calculations. Theoretical calculations also enable to predict the X-ray absorption spectral fingerprint of polarons in Mo-BiVO4. After photo-electrochemical operation, the degraded Mo-BiVO4 films show similar grain center and grain boundary spectra indicating V2O5 dissolution in the course of the reaction. Overall, these findings provide valuable insights into the degradation mechanism and the impact of material heterogeneities on the material performance and stability of polycrystalline photoelectrodes. © 2020 The Authors. Published by Wiley-VCH GmbH https://onlinelibrary-wiley-com.recursosbiblioteca.unab.cl/doi/10.1002/smll.202001600

A hybrid catalyst-bonded membrane device using gaseous reactants for a carbon monoxide reduction (COR) reaction in the cathode chamber, an aqueous electrolyte for an oxygen evolution reaction (OER) in the anode chamber, and an anion exchange membrane (AEM) for product separation was modeled, constructed, and tested. The Cu electrocatalyst was electrodeposited onto gas diffusion layers (GDLs) and was directly bonded to AEM by mechanical pressing in the hybrid device. The impacts of relative humidity at the cathode inlet on the selectivity and activity of COR were investigated by computational modeling and experimental methods. At a relative humidity of 30%, the Cu-based catalyst in the hybrid device exhibited a total operating current density of 87 mA cm-2 with a -2.0 V vs Ag/AgCl reference electrode, a Faradaic efficiency (FE) for C2H4 generation of 32.6%, and an FE for a liquid-based carbon product of 42.6%. Significant improvements in the partial current densities for COR were observed in relation to planar electrodes or flooded gas diffusion electrodes (GDEs). In addition, a custom test bed was constructed to characterize the oxidation states of the Cu catalysts in real time along with product analysis though the backside of the GDLs via operando X-ray absorption (XAS) measurements.

Gallium phosphide (GaP) is a promising catalyst material used in the photo-electrochemical carbon dioxide (CO2) reduction reaction (CO2RR). However, experimental data needed to interpret the interactions between CO2 and GaP at their interfaces must be gathered in order to develop advanced GaP based catalysts for the CO2RR. Here we used ambient pressure x-ray photoelectron spectroscopy to characterize the surface chemistry at 298 K on the GaP surface exposed to CO2 alone and in the presence of H2O under both dark and illuminated conditions. We found that a carbonate-like configuration is stable on the GaP surface exposed solely to 0.35 Torr CO2. Shining solar light promoted the CO2 dissociation process on the surface while negligibly influencing the CO2 adsorption configuration on GaP. Based on the surface chemistry change under dark and illuminated conditions, we propose a CO2 dissociation pathway on GaP. We also found that linear physisorbed CO2 formed on the surface of GaP when 0.35 Torr CO2 is co-dosed with 0.35 Torr H2O. Co-dosing H2O with CO2 also created a surface dipole, which is further influenced by solar light illumination. This work provides a fundamental atomic level understanding of how CO2 adsorption and activation happened on the GaP surface and how it was further influenced by solar light.

In patients with suspected acute coronary syndrome (ACS), troponin testing is effective for diagnosis and prognosis. Troponin testing has now expanded to include patients without suspected ACS. This nonselective troponin testing has unknown consequences for resource utilization and outcome. Therefore, we examined selective versus nonselective troponin testing with respect to patient characteristics, resource utilization, and outcome.This retrospective 1-year study included all patients with troponin testing at a U.S. emergency department. Testing was classified as selective (ACS) or nonselective (non-ACS) based on admission ICD-9 codes. Troponin upper reference limit (URL) was ≥99th percentile.Among 47,053 patients, troponin was measured in 9109 (19%) of whom 5764 were hospitalized. Admission diagnosis was non-ACS in 4427 (77%) and ACS in 1337 (23%). Non-ACS patients were older, 71±17 versus 65±16 years, with longer hospital stay, 77 versus 32 h, and greater 1-year mortality 22% versus 6.7%; P.001. In patients with troponin ≥URL, revascularization was performed in 64 (4.7%) of non-ACS versus 213 (48%) of ACS; P.001. In patients with troponinURL, 1-year mortality was 16% in non-ACS versus 3.5% in ACS; P.001. In those with troponin ≥URL, 1-year mortality was 35% in non-ACS versus 13% in ACS; P.001. Death was non-cardiac in80% of the non-ACS population CONCLUSIONS: Contemporary troponin testing is frequently nonselective. The non-ACS and ACS populations differ significantly regarding clinical characteristics, revascularization rates, and outcomes. Troponin elevation is a powerful predictor of 1-year mortality in non-ACS, this association reveals an opportunity for risk stratification and targeted therapy.In patients with suspected acute coronary syndrome (ACS), troponin testing is effective for diagnosis and prognosis. However, troponin testing has now expanded to include patients without suspected ACS. This nonselective troponin testing has unknown consequences for hospital resource utilization and patient outcome. Our findings demonstrate contemporary troponin testing is largely nonselective (77% of testing was performed in patients without acute coronary syndrome). In comparison to patients with acute coronary syndrome, those with non-acute coronary syndrome are older, with longer hospital stay, lower revascularization rates, and greater 1-year mortality. Troponin elevation identifies a high-risk population in both acute coronary syndrome and non-acute coronary syndrome populations, yet effective treatment for the latter is lacking.

Aims: Using a comprehensive large prospective regional ST-elevation myocardial infarction (STEMI) system database, we evaluated the prevalence, clinical and angiographic characteristics, and outcomes in patients with ischemic symptoms and new or presumed new left bundle branch block (LBBB). We then tested a new hierarchical diagnosis and triage algorithm to identify more accurately new LBBB patients with an acute culprit lesion. Methods and results: From March 2003 to June 2013, 3903 consecutive STEMI patients were treated using the Minneapolis Heart Institute regional STEMI protocol including 131 patients (3.3%) with new LBBB. These patients had fewer culprit arteries (54.2% vs. 86.4%; PConclusion: Patients with acute ischemic symptoms and new LBBB represent a high-risk population with unique clinical challenges. If validated in an independent dataset, the new algorithm may improve the diagnostic accuracy regarding reperfusion therapy for new LBBB patients.

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Safe and practical solar-driven hydrogen generators must be capable of efficient and stable operation under diurnal cycling with full separation of gaseous H2and O2products. In this study, a novel architecture that fulfills all of these requirements is presented. The approach is inherently scalable and provides versatility for operation under diverse electrolyte and lighting conditions. The concept is validated using a 1 cm2triple-junction photovoltaic cell with its illuminated photocathode protected by a composite coating comprising an organic encapsulant with an embedded catalytic support. The device is compatible with operation under conditions ranging from 1 m H2SO4to 1 m KOH, enabling flexibility in selection of semiconductor, electrolyte, membrane, and catalyst. Stable operation at a solar-to-hydrogen conversion efficiency of >10% is demonstrated under continuous operation, as well as under diurnal light cycling for at least 4 d, with simulated sunlight. Operational characteristics are validated by extended time outdoor testing. A membrane ensures products are separated, with nonexplosive gas streams generated for both alkaline and acidic systems. Analysis of operational characteristics under different lighting conditions is enabled by comparison of a device model to experimental data.

First-medical-contact-to-device (FMC2D) times have improved over the past decade, as have clinical outcomes for patients presenting with ST-elevation myocardial infarction (STEMI). However, with improvements in FMC2D times, false activation of the cardiac catheterization laboratory (CCL) has become a challenging problem. The authors define false activation as any patient who does not warrant emergent coronary angiography for STEMI. In addition to clinical outcome measures for these patients, STEMI systems should collect data regarding the total number of CCL activations, the total number of emergency coronary angiograms, and the number revascularization procedures performed.

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for ST elevation myocardial infarction (STEMI). However, only one-third of hospitals in the US have PCI availability 24/7. For non-PCI hospitals, transfer remains the optimal strategy. For expected delays of greater than 120 minutes, a pharmacoinvasive strategy is recommended. In patients with evidence of failed reperfusion or hemodynamic instability, immediate rescue PCI should be performed. All other patients should undergo routine cardiac catheterization and PCI within 24 hours after fibrinolysis. A pharmacoinvasive strategy is best implemented within an organized regional STEMI system with prospective standardized transfer protocols.

Patients with presumed ST-elevation myocardial infarction (STEMI) have no clear culprit artery in approximately 10-15% of cases. We examined the value of cardiac magnetic resonance (CMR) for diagnosis in patients with "no culprit" STEMI. Data from a comprehensive prospective registry of STEMI patients were reviewed from March 2003 to December 2009. "No culprit" patients were followed for diagnosis and clinical outcome. CMR was performed at the discretion of the attending cardiologist. Of 2728 consecutive presumed STEMI patients, 412 (15%) had no clear culprit artery. Of these, 202 (49%) had abnormal cardiac biomarkers with a definitive diagnosis in 157 (78%). Diagnoses in this group included myocardial infarction without a culprit lesion (24%), myopericarditis (22%), and stress cardiomyopathy (21%). In 210 (51%) patients with normal biomarkers, only 84 (40%) received a definitive diagnosis. Diagnoses in this group included myopericarditis (27%), noncardiac causes (21%), and cardiomyopathy (14%). CMR was performed in 123 (30%) "no culprit" patients. Patients who had CMR were more likely to have a definitive diagnosis than those who did not (95/123 [77%] vs. 144/289 [50%]; P=0.01). In particular, "no culprit" patients with abnormal biomarkers were more likely to have a definitive diagnosis with CMR. CMR led to a diagnosis different from the presumptive clinical diagnosis in 53% of all cases. CMR is a valuable diagnostic tool to improve diagnostic accuracy in patients with "no culprit" STEMI.

Background— Transfer for primary percutaneous coronary intervention (PCI) is superior to fibrinolysis if performed in a timely manner but frequently requires dislocation of patients and their families from their local community. Although patient satisfaction is increasingly viewed as an important quality indicator, there are no data on how emergent transfer for PCI affects patients with ST–segment-elevation myocardial infarction and their families. Methods and Results— The Minneapolis Heart Institute’s Level 1 Regional ST–Segment-Elevation Myocardial Infarction program is designed to facilitate emergent transfer for PCI in patients with ST–segment-elevation myocardial infarction from 31 rural and community hospitals. To determine the effect of emergent transfer, questionnaires were given to 152 patients and their families who survived to hospital discharge with a 65.8% response rate (mean age, 63.9 years; 29% women). Ninety-five percent of patients felt the reasons and process of transfer were well explained, and 97% felt transfer for care was necessary. Despite this, 15% of patients would have preferred to stay in their local hospital. The majority of the families felt the transfer process (88%) and family member’s condition (94%) were well explained. Although 99% felt it was necessary for their family member to be transferred for specialized care, 11% of families still would have preferred that their family members remain at the local community hospital. Conclusions— Our results suggest that ST–segment-elevation myocardial infarction patients and families can be informed, even in time-critical situations, about the transfer process for PCI and understand the need for specialized care. Still, a significant minority would prefer to stay at their local hospital, despite acknowledging transfer for PCI provided optimal care.

Gas-diffusion electrodes (GDEs) for electrochemical CO2 reduction allow for an order-of-magnitude increase in obtainable limiting current densities (~100 mA/cm2) compared to planar systems (~10 mA/cm2) due to the increase in CO2 flux, catalyst surface area, and reduction in diffusion length. Despite this improvement, aqueous GDE systems suffer from extensive catalyst dissolution/delamination and membrane degradation under operating conditions, as well as exhibit significant ohmic resistances stemming from their electrolyte layers. These characteristics limit the current densities that can be achieved at applied overpotentials and render them impractical for industrial implementation. Membrane-electrode assemblies (MEAs), consisting of humidified gaseous feeds at one or both electrodes and no aqueous electrolyte between the electrodes (i.e. only using a solid ion-conducting polymer or ionomer as an electrolyte), can overcome the limitations of the aqueous GDE. In this poster, two MEA cell designs will be addressed: Full-MEA (humidified gaseous feeds at both the anode and cathode) and Exchange-MEA (humidified gaseous feed at the cathode and an adjoining water or salt solution, e.g. KHCO3 or KOH, at the anode to provide hydration and a source of ions). The experimental performance results obtained from the near-optimized vapor-fed Full-MEA and H2O Exchange-MEA systems for CO2RR at ambient temperature and pressure conditions and the details of our ongoing work in building a fully integrated, tandem/cascade catalysis device are described. This poster also details plans for future investigations in exploring critical fabrication, operating conditions, and MEA properties. Acknowledgements This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. We would also like to thank Nemanja Danilovic, Kun Jiang, Julie Fornaciari, Yagya Regmi, Douglas Kushner, and Christianna Lininger for their help, discussions, and guidance in the course of this research project.

Author(s): Kistler, TA; Larson, D; Walczak, K; Agbo, P; Sharp, ID; Weber, AZ; Danilovic, N | Abstract: Photoelectrochemical (PEC) water splitting has the potential to significantly reduce the costs associated with electrochemical hydrogen production through the direct utilization of solar energy. Many PEC cells utilize liquid electrolytes that are detrimental to the durability of the photovoltaic (PV) or photoactive materials at the heart of the device. The membrane-electrode-assembly (MEA) style, PEC cell presented herein is a deviation from that paradigm as a solid electrolyte is used, which allows the use of a water vapor feed. The result of this is a correspondent reduction in the amount of liquid and electrolyte contact with the PV, thereby opening the possibility of longer PEC device lifetimes. In this study, we demonstrate the operation of a liquid and vapor-fed PEC device utilizing a commercial III-V photovoltaic that achieves a solar-to-hydrogen (STH) efficiency of 7.5% (12% as a PV-electrolyzer). While device longevity using liquid water was limited to less than 24 hours, replacement of reactant with water vapor permitted 100 hours of continuous operation under steady-state conditions and diurnal cycling. Key findings include the observations that the exposure of bulk water or water vapor to the PV must be minimized, and that operating in mass-transport limited regime gave preferable performance.

Microfabricated devices designed to provide phase contrast in the transmission electron microscope must be free of phase distortions caused by unexpected electrostatic effects. We find that such phase distortions occur even when a device is heated to 300 °C during use in order to avoid the formation of polymerized, carbonaceous contamination. Remaining factors that could cause unwanted phase distortions include patchy variations in the work function of a clean metal surface, radiation-induced formation of a localized oxide layer, and creation of a contact potential between an irradiated area and the surround due to radiation-induced structural changes. We show that coating a microfabricated device with evaporated carbon apparently eliminates the problem of patchy variation in the work function. Furthermore, we show that a carbon-coated titanium device is superior to a carbon-coated gold device, with respect to radiation-induced electrostatic effects. A carbon-coated, hybrid double-sideband/single-sideband aperture is used to record in-focus, cryo-EM images of monolayer crystals of streptavidin. Images showing no systematic phase error due to charging are achievable under conditions of low-dose data collection. The contrast in such in-focus images is sufficient that one can readily see individual streptavidin tetramer molecules. Nevertheless, these carbon-coated devices perform well for only a limited length of time, and the cause of failure is not yet understood.

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., Metal oxide semiconductors are promising materials for solar energy capture but can suffer from stability problems. Here, the authors present a methodology for evaluating corrosion mechanisms and apply it to BiVO4, revealing chemical instabilities that are not predicted from thermodynamic considerations alone.

Prehospital care is critical to achieve the goal of timely reperfusion in patients with ST-elevation myocardial infarction. Prehospital care is delivered by emergency medical services (EMS) personnel, which include emergency medical dispatchers, first responders, and ambulance response. There is considerable variation in the training and capabilities of the EMS providers in the United States depending on the location (ie, rural vs urban) and local jurisdictions. In this article, the key components of prehospital care of the patient with ST-elevation myocardial infarction and the various levels of training and capabilities of EMS providers are discussed.

In 2007, there were ≈4 million visits to emergency departments in the United States with a primary diagnosis of cardiovascular disease.1 Current forecasts estimate that the direct medical costs for cardiovascular disease in the United States will triple by 2030 to $800 billion dollars.2 Acute cardiovascular emergencies, including ST-segment–elevation myocardial infarction (STEMI), non-STEMI/unstable angina, out-of-hospital cardiac arrest (OHCA), acute aortic dissection (AAD), abdominal aortic aneurysm (AAA), stroke, and acute decompensated heart failure/cardiogenic shock, require rapid, complex, and resource-intensive care and confer a high risk of mortality. Regionalized systems of care enable patients with complex and urgent medical needs to be systematically directed to hospitals that can provide the highest level of clinical expertise and resources (ie, designated centers). Historically, trauma systems have used this paradigm with improved outcomes. There is a growing focus on regionalized medical care as a strategy to leverage limited resources, to manage cost, and to improve outcomes for other medical emergencies. National cardiovascular organizations have already published recommendations for the establishment of centers and regional systems of care for STEMI,3–6 cardiac arrest,7–9 and stroke.10,11 The purpose of this article is to propose the concept of a cardiovascular emergency system, ie, a comprehensive regional system of care for cardiovascular emergencies led by a designated cardiovascular emergency receiving center. Over the past decade, the Minneapolis Heart Institute at Abbott Northwestern Hospital (MHI-ANW) has implemented regional systems of care for STEMI,12 OHCA,13 AAD,14 non-STEMI, and AAA. These initiatives provide a demonstration of the clinical programs and supportive network that reflect the burgeoning framework of a cardiovascular emergency system. Informed by this work, we discuss the historical perspective of, rationale for, and proposed principal elements of a cardiovascular emergency system. Trauma systems are the prototype for …

We present a modern, light portable device specifically designed for environmental samples for cryogenic transmission-electron microscopy (cryo-TEM) by on-site cryo-plunging. The power of cryo-TEM comes from preparation of artifact-free samples. However, in many studies, the samples must be collected at remote field locations, and the time involved in transporting samples back to the laboratory for cryogenic preservation can lead to severe degradation artifacts. Thus, going back to the basics, we developed a simple mechanical device that is light and easy to transport on foot yet effective. With the system design presented here we are able to obtain cryo-samples of microbes and microbial communities not possible to culture, in their near-intact environmental conditions as well as in routine laboratory work, and in real time. This methodology thus enables us to bring the power of cryo-TEM to microbial ecology.

Aims To determine the safety and efficacy of a pharmaco-invasive reperfusion strategy utilizing half-dose fibrinolysis combined with transfer for immediate percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI) patients presenting to remote rural hospitals. Primary PCI is preferred for STEMI if performed in a timely manner. However

Background— Regional ST-segment–elevation myocardial infarction systems are being developed to improve timely access to primary percutaneous coronary intervention (PCI). System delays may diminish the mortality benefit achieved with primary PCI in ST-segment–elevation myocardial infarction patients, but the specific reasons for and clinical impact of delays in patients transferred for PCI are unknown. Methods and Results— This was a prospective, observational study of 2034 patients transferred for primary PCI at a single center as part of a regional ST-segment–elevation myocardial infarction system from March 2003 to December 2009. Despite long-distance transfers, 30.4% of patients (n=613) were treated in ≤90 minutes and 65.7% (n=1324) were treated in ≤120 minutes. Delays occurred most frequently at the referral hospital (64.0%, n=1298), followed by the PCI center (15.7%, n=317) and transport (12.6%, n=255). For the referral hospital, the most common reasons for delay were awaiting transport (26.4%, n=535) and emergency department delays (14.3%, n=289). Diagnostic dilemmas (median, 95.5 minutes; 25th and 75th percentiles, 72–127 minutes) and nondiagnostic initial ECGs (81 minutes; 64–110.5 minutes) led to delays of the greatest magnitude. Delays caused by cardiac arrest and/or cardiogenic shock had the highest in-hospital mortality (30.6%), in contrast with nondiagnostic initial ECGs, which, despite long treatment delays, did not affect mortality (0%). Significant variation in both the magnitude and clinical impact of delays also occurred during the transport and PCI center segments. Conclusions— Treatment delays occur even in efficient systems for ST-segment–elevation myocardial infarction care. The clinical impact of specific delays in interhospital transfer for PCI varies according to the cause of the delay.

The electrical conductance and the optical density of evaporated carbon films are measured as a function of the thickness of the films. The resulting data show that up to a thickness of approximately 4 nm, carbon films are optically transparent and electrically insulating. The same data also suggest that this insulating character persists near to the surface when the overall thickness is further increased. Since a support film with poor surface conductivity is undesirable for many applications in electron microscopy, we suggest that the usefulness of evaporated carbon films in electron microscopy might be further improved by doping or by other methods that improve the electrical conductivity near the surface.

One of the main challenges towards achieving high-efficiency solar-fuel generators performing CO2 reduction are the mass-transport limitations in traditional aqueous systems due to CO2 interactions/solubility and boundary-layer thickness. To circumvent these issues, gas-diffusion electrodes (GDEs) are considered wherein the CO2 is fed in a vapor form into a porous electrode. In this talk, we will explore the various tradeoffs endemic in GDE architectures. This is accomplished through multiphysics modeling of the cells including breakdowns of the various limiting phenomena. In addition, experimental data on the GDEs for CO2 reduction will be presented using both Ag and Cu-based catalysts. Key is understanding the potential distributions with the GDE and how this along with the observed higher current densities impact product selectivity with Cu-based catalysts. Finally, comments will be made concerning the possibilities of light inclusion in GDEs to enable solar CO2 reduction as well as the benefits of GDEs that extend beyond higher current-density operation including unprecedented control of the local environment compared to traditional, aqueous planar designs. Acknowledgements The material is based on work performed at the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, through the Office of Science of the U.S. Department of Energy under award no. DE-SC0004993

Pretreatment with clopidogrel reduces ischemic complications before percutaneous coronary intervention (PCI). Limited data exist regarding the effect of pretreatment for ST-segment elevation myocardial infarction (STEMI) patients undergoing primary PCI.Prospective data were analyzed from a regional STEMI system using rapid transfer for primary PCI in 30 community hospitals. Zone 1 community hospitals are60 miles and Zone 2 hospitals are 60 to 210 miles away from the PCI hospital. Compared with 63 minutes in the PCI hospital, median door-to-balloon times were 94 minutes in Zone 1 and 123 minutes in Zone 2 hospitals. All patients received aspirin, unfractionated heparin, and clopidogrel 600 mg in the emergency department of the presenting hospital within 15 minutes of diagnosis.From April 2003 through December 2008, 2,014 consecutive STEMI patients were pretreated with clopidogrel before PCI, with a median (25th-75th percentile) duration from pretreatment to PCI of 75 (58-93) minutes. Patients with longer pretreatment duration had significantly reduced reinfarction/reischemia at 30 days (Zone 1: 0.85%, Zone 2: 0.9%) compared with nontransferred patients (3.2%, P = .001) as well as reduced stent thrombosis (Zone 1: 0.6%, Zone 2: 0.6% vs Abbott Northwestern: 2.0%; P = .04). Similarly, pretreatment duration of60 minutes before PCI had reduced 30-day reinfarction/reischemia (1.0% vs 2.9%, P = .003). There were no significant differences in mortality or major bleeding.ST-segment elevation myocardial infarction patients undergoing primary PCI in a regional STEMI network who received earlier pretreatment with a 600-mg loading dose of clopidogrel had less ischemic complications without increased bleeding or mortality.

Developmental programming is the concept that a maternal stimulus or insult at a critical period in fetal development has long-term effects on the offspring. Historically, considerable effort has been made to understand how nutrition influences health and productivity during the postnatal period. Whereas maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, less is known about how maternal nutrition affects the health and productivity of the offspring. Conceptus growth is sensitive to direct and indirect effects of maternal dietary intake. Even from the earliest stages of embryonic life, when nutrient requirements for conceptus growth are negligible, alterations in tissue composition can occur, influencing future growth of the compromised organ system. Not only is neonatal health compromised, but subsequent health may also be programmed because offspring from undernourished dams have exhibited poor growth and productivity and have developed significant diseases later in life. Although the literature is now evolving, with increasing evidence of how maternal nutrient restriction impairs several prenatal physiological variables, few studies have evaluated postnatal growth and development in livestock species, and fewer have evaluated it in beef cattle. In addition, very few studies have evaluated restriction of specific components of the diet during pregnancy (such as protein) on offspring growth and performance. This review focuses on how maternal nutrition affects conceptus growth and postnatal responses in beef cattle.

The American College of Cardiology and the American Heart Association guidelines are the nationally accepted standards for the treatment of patients with acute coronary syndromes. Despite this recognition, adherence to guideline recommendations remains suboptimal with 25% of opportunities to provide guideline appropriate care missed. To address performance gaps related to acute coronary syndrome care and improve patient outcomes, a performance improvement (PI) initiative was designed for cardiologists and emergency department physicians. As an American Medical Association-approved, standardized continuing medical education initiative, participating physicians can earn up to 20 American Medical Association-PRA Category 1 Credits by completing 2 phases of self-assessment in addition to developing and implementing a PI plan to address self-identified areas where improvement in patient care is needed. As the second in a series of 3 articles, this article describes the initial data submitted by 101 participating physicians and how their treatment practices compared with American College of Cardiology/American Heart Association guidelines as well as with current national standards. Overall, participating physicians meet guideline expectations with performance and documentation of a 12-lead electrocardiography, measurement of cardiac biomarkers, and administration of aspirin. Identified areas of improvement were the standardization of treatment protocols, use of risk assessment scores, appropriate dosing of anticoagulants, and improvement in patient treatment times. A noted challenge of this PI initiative is the low rate of physician participation, with fewer than 10% of registered physicians actively submitting patient data. This fact may reflect several barriers to PI, such as: (1) lack of time to collect and submit data, (2) the belief that current practices do not need to be improved, and (3) the need for system-based improvements.

Reduced-Dose Fibrinolytic Acceleration of ST-Segment Elevation Myocardial Infarction Treatment Coupled with Urgent Percutaneous Coronary Intervention Compared to Primary Percutaneous Coronary Inter...

Recent developments have provided a unique opportunity for the organization of regional ST-elevation myocardial infarction (STEMI) receiving center (SRC) networks. Because cumulative evidence has demonstrated that rapid primary percutaneous coronary intervention (PCI) is the most effective reperfusion strategy for acute STEMI, the development of integrated SRC networks could extend the benefits of primary PCI to a much larger segment of the US population. Factors that favor the development of regional SRC networks include results from recently published clinical trials, insight into contemporary STEMI treatment patterns from observational registries, experience with the nation's current trauma system, and technological advances. In addition, the 2004 American College of Cardiology/American Heart Association STEMI guidelines have specified that optimal "first medical contact-to-balloon" times should be

Sirolimus-eluting stents (SESs) are superior to bare metal stents (BMSs) for percutaneous coronary intervention, but data regarding SESs in ST-segment elevation myocardial infarction (STEMI) are limited. We investigated the clinical outcomes of patients with STEMI who were treated with SESs. We measured clinical characteristics and acute and long-term outcomes in 306 consecutive patients with STEMI who received a SES (n = 156) or a BMS (n = 150). Patients were followed for death, nonfatal reinfarction, and target vessel revascularization. Patients with SESs had a 0.6% in-hospital mortality rate versus 5.3% in patients with BMSs (p = 0.015). Six-month mortality rates were 1.9% (SES) and 10.1% (BMS, p = 0.003). At 6 months, patients with SESs were less likely to have target vessel revascularization (1.3% vs 8.1%, p = 0.005) and achieve the composite end point (3.2% vs 16.1%, p = 0.0001). No subacute thrombosis or clinical restenosis occurred in the SES group. Patients who received BMSs were older, received more stents, and had more myocardial damage, worse renal function, and lower ejection fractions than did those in the SES group. By multivariate discriminant analysis, stent type (SES vs BMS) was the most significant determinant of the 6-month composite end point (p = 0.01) and the need for target vessel revascularization (p = 0.02). In conclusion, SESs are safe and effective in STEMI at 6 months.

Despite substantial progress in the diagnosis and treatment of acute ST-segment elevation myocardial infarction (STEMI), implementation of this knowledge into routine clinical practice has been variable. It has become increasing clear that primary percutaneous coronary intervention (PCI) is the preferred method of reperfusion if it can be performed in a timely manner. Recent European data suggest that transfer for direct PCI may also be preferable to fibrinolytic therapy. We believe it is time to establish a national policy for treatment of patients with STEMI to develop a coordinated system of care similar to that of the level 1 trauma system.

We have been investigating the function and gene expression of connexins by vascular wall cells, especially Connexin43 (Cx43) in bovine aortic endothelial cells (BAEC). In this study, we tested the effects of carbenoxolone (CBN), a gap junction communication (GJC) blocker on the junctional transfer of Lucifer yellow in BAEC. CBN is a water-soluble derivative of the liquorice-root extract 18-alpha-glycyrrhetinic acid. CBN rapidly abolished dye-transfer in the scrape-load transfer assay (a measure of GJC) in a reversible and dose-dependent fashion. We then asked whether the BAEC might somehow compensate for the loss of junctional communication by altering the expression of connexins. Thus, we treated BAEC with 100 microM CBN in serum free medium and determined the total Cx43 cellular distribution (immunostaining) and protein content (immunoblotting). Besides changes in distribution, by 6 h, Cx43 content levels increased to 166% +/- 22% (P < 0.0001) of controls. RNA blot data showed two-three fold increases in Cx43 message in BAEC after 6 h of CBN treatment, suggesting transcriptional control. Since CBN has structural similarities to corticosteroids, we tested both aldosterone and prednisolone but neither drug increased Cx43 levels, suggesting that the CBN response was not due to a generalized steroid effect. Staurosporine inhibited the CBN-induced increase in Cx43 content, suggesting a role for kinases in the signaling pathway. Further studies with inhibitors indicated that PKA but not PKC was implicated. In summary, CBN blocks junctional communication and modulates Cx43 expression in BAEC. These results suggest a feedback mechanism for control of connexin expression based on junctional patency.

Objectives: To obtain information regarding the current use of guidelines and protocols and quality assessment practices for the management of ST-segment elevation myocardial infarction in Minnesota hospitals without cardiac catheterization laboratories. Methods: Structured surveys were mailed in 2003 to emergency department medical directors or nurse managers in 111 hospitals in Minnesota that did not have cardiac catheterization laboratories. Of the 111 hospitals surveyed, 104 (94%) responded. Results: Sixty-three percent of responding hospitals have guidelines or protocols; 57% use standing orders for ST-segment elevation myocardial infarction. Thirty-three percent have neither. Of those with guidelines, protocols, or standing orders, 8% address triage and transfer criteria, 86% thrombolytics, 91% aspirin, and 71% beta-blockers. Fifty percent have quality assessment processes in place for ST-segment elevation myocardial infarction. Conclusions: Recommendations from the National Heart Attack Alert Program issued more than ten years ago and, more recently, the updated American College of Cardiology/American Heart Association Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction suggest development of emergency department and hospital-specific guidelines and protocols for ST-segment elevation myocardial infarction. Currently, only two thirds of community hospitals in Minnesota have these in place; when present, these guidelines are often incomplete and rarely address transfer criteria to hospitals with percutaneous coronary intervention capability. Quality assessment occurred in 50% of hospitals surveyed. Programs to help community hospitals develop and implement guidelines and quality improvement should be encouraged and supported.

We have been studying the relationships between cell growth and the expression of the gap junction protein Connexin43 (Cx43) in cultured bovine aortic endothelial cells (BAEC). As part of these studies, we examined the effect of the growth inhibitory cytokine TGF-beta1 on Cx43 expression. We have shown recently that TGF-beta treatment increases Cx43 mRNA and synthesis, content, and half-life of the protein within 24 h, which leads, over the course of days, to an accumulation of Cx43 in large, intensely immunostaining vesicles, filling much of the perinuclear cytoplasmic space. In the current study, based on their distribution and markers, we identified these vesicles as lysosomes/autophagosomes. Cx43 immunostaining and staining with a fluorescent probe for acidic compartments are coincident, as retention of a fluorescent-labeled low-density lipoprotein occurs in a similar pattern and the same staining pattern can be detected in the treated cells using other markers for lysosomal compartments. TEM revealed prominent lysosomal figures with considerable heterogeneous material. After withdrawal of TGF-beta, the accumulated Cx43 was cleared only slowly, with some brightly immunoreactive cells remaining even after 72 h. The prolonged appearance (based on immunoreactivity in situ and in immunoblots) of intact vesicular Cx43 in the treated cells suggests decreased degradation, resulting from impaired lysosomal activity. These data not only emphasize the importance of the lysosome in connexin degradation, but also show that TGF-beta can cause an alteration in lysosomal functioning, with implications for cellular metabolism.