| 1. |
- Afzal, Muhammad, et al.
(författare)
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Analysis of a perovskite-ceria functional layer-based solid oxide fuel cell
- 2017
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 42:27, s. 17536-17543
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Tidskriftsartikel (refereegranskat)abstract
- A fuel cell based on a functional layer of perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) composited samarium doped ceria (SDC) has been developed. The device achieves a peak power density of 640.4 mW cm(-2) with an open circuit voltage (OCV) of 1.04 Vat 560 degrees C using hydrogen and air as the fuel and oxidant, respectively. A numerical model is applied to fit the experimental cell voltage. The kinetics of anodic and cathodic reactions are modeled based on the measurements obtained by electrochemical impedance spectroscopy (EIS). Modeling results are in well agreement with the experimental data. Mechanical stability of the cell is also examined by using analysis with field emission scanning electron microscope (FESEM) associated with energy dispersive spectroscopy (EDS) after testing the cell performance.
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| 2. |
- Ali, Amjad, et al.
(författare)
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Electrochemical study of composite materials for coal-based direct carbon fuel cell
- 2018
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 43:28, s. 12900-12908
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Tidskriftsartikel (refereegranskat)abstract
- The efficient conversion of solid carbon fuels into energy by reducing the emission of harmful gases is important for clean environment. In this regards, direct carbon fuel cell (DCFC) is a system that converts solid carbon directly into electrical energy with high thermodynamic efficiency (100%), system efficiency of 80% and half emission of gases compared to conventional coal power plants. This can generate electricity from any carbonaceous fuel such as charcoal, carbon black, carbon fiber, graphite, lignite, bituminous coal and waste materials. In this paper, ternary carbonate-samarium doped ceria (LNK-SDC) electrolyte has been synthesized via co-precipitation technique, while LiNi-CuZnFeO (LNCZFO) electrode has been prepared using solid state reaction method. Due to significant ionic conductivity of electrolyte LNK-SDC, it is used in DCFC. Three types of solid carbon (lignite, bituminous, sub-bituminous) are used as fuel to generate power. The X-ray diffraction confirmed the cubic crystalline structure of samarium doped ceria, whereas XRD pattern of LNCZFO showed its composite structure. The proximate and ultimate coal analysis showed that fuel (carbon) with higher carbon content and lower ash content was promising fuel for DCFC. The measured ionic conductivity of LNK-SDC is 0.0998 Scm(-1) and electronic conductivity of LNCZFO is 10.1 Scm(-1) at 700 degrees C, respectively. A maximum power density of 58 mWcm(-2) is obtained using sub bituminous fuel.
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| 3. |
- Bassand, Jean-Pierre, et al.
(författare)
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Relationship between baseline haemoglobin and major bleeding complications in acute coronary syndromes
- 2010
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 31:1, s. 50-58
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: In patients with acute coronary syndromes (ACS), the negative impact of baseline haemoglobin levels on ischaemic events, particularly death, is well established, but the association with bleeding risk is less well studied. The aim of this study was to assess the impact of baseline haemoglobin levels on major bleeding complications. METHODS AND RESULTS: Pooled analysis of OASIS 5 and 6 data involving 32 170 patients with ACS with and without ST-segment elevation was performed. The association between baseline haemoglobin and major bleeding or ischaemic events was examined using multiple regression model. MAIN OUTCOME MEASURES: were 30-day rates of major bleeding, death, and death/myocardial infarction (MI) analysed according to baseline haemoglobin levels. Baseline haemoglobin level independently predicted the risk of overall, procedure-related, and non-procedure-related major bleedings at 30 days [odds ratio (OR) 0.94, 95% CI 0.90-0.98; OR 0.94, 95% CI 0.90-0.99; and OR 0.89, 95% CI 0.83-0.95, respectively, per 1 g/dL haemoglobin increment above 10 g/dL]. In addition, a curvilinear relationship between baseline haemoglobin levels and death at 30 days was observed with a 6% decrease in the risk for every 1 g/dL haemoglobin increment above 10 g/dL up to 15.9 g/dL (OR 0.94, 95% CI 0.90-0.98) and a 19% increase above this value (OR 1.19, 95% CI, 0.98-1.43). A similar relationship for the composite outcome of death/MI was observed. CONCLUSION: A low baseline haemoglobin level is an independent predictor of the risk of major bleeding in ACS as well as of the risk of death and death and MI. Among other predictors of bleeding risk, baseline haemoglobin should be taken into account in patients presenting with ACS. Clinical trial registration: ClinicalTrials.gov number, NCT00139815. http://clinicaltrials.gov/ct2/show/NCT00139815?term=NCT00139815&rank=1.
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| 4. |
- Budaj, Andrzej, et al.
(författare)
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Improving clinical outcomes by reducing bleeding in patients with non-ST-elevation acute coronary syndromes
- 2009
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 30:6, s. 655-61
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Bleeding in patients with coronary artery disease has been linked with adverse outcomes. We examined the incidence and outcomes after bleeding in 20 078 patients with acute coronary syndromes (ACS) enrolled in the OASIS-5 trial who were treated with fondaparinux or the low-molecular weight heparin, enoxaparin. METHODS AND RESULTS: Nine hundred and ninety (4.9%) patients developed major bleeding and 423 (2.1%) developed minor bleeding. Fondaparinux compared with enoxaparin reduced fatal bleeding [0.07 vs. 0.22%, relative risk (RR) 0.30, 95% CI: 0.13-0.71], non-fatal major bleeding (2.2 vs. 4.2%, RR 0.52, 95% CI: 0.44-0.61), minor bleeding (1.1 vs. 3.2%, RR 0.34, 95% CI: 0.27-0.42), and need for transfusion (1.8 vs. 3.1%, RR 0.56, 95% CI: 0.47-0.61) during the first 9 days. One of every six deaths during the first 30 days occurred in patients who experienced bleeding. Cox proportional hazards model revealed that major bleeding was associated with about a four-fold increased hazard of death, myocardial infarction, or stroke during the first 30 days and about a three-fold increased hazard during 180 days of follow up. CONCLUSION: Bleeding in patients with ACS is a powerful determinant of fatal and non-fatal outcomes. Reducing the risk of bleeding using a safer anticoagulant strategy during the first 9 days is associated with substantial reductions in morbidity and mortality.
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| 5. |
- Connolly, Stuart J, et al.
(författare)
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Dronedarone in High-Risk Permanent Atrial Fibrillation
- 2011
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 365:24, s. 2268-2276
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Tidskriftsartikel (refereegranskat)abstract
- Background Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular anti-arrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in high-risk permanent atrial fibrillation. Methods We assigned patients who were at least 65 years of age with at least a 6-month history of permanent atrial fibrillation and risk factors for major vascular events to receive dronedarone or placebo. The first coprimary outcome was stroke, myocardial infarction, systemic embolism, or death from cardiovascular causes. The second coprimary outcome was unplanned hospitalization for a cardiovascular cause or death. Results After the enrollment of 3236 patients, the study was stopped for safety reasons. The first coprimary outcome occurred in 43 patients receiving dronedarone and 19 receiving placebo (hazard ratio, 2.29; 95% confidence interval [CI], 1.34 to 3.94; P=0.002). There were 21 deaths from cardiovascular causes in the dronedarone group and 10 in the placebo group (hazard ratio, 2.11; 95% CI, 1.00 to 4.49; P=0.046), including death from arrhythmia in 13 patients and 4 patients, respectively (hazard ratio, 3.26; 95% CI, 1.06 to 10.00; P=0.03). Stroke occurred in 23 patients in the dronedarone group and 10 in the placebo group (hazard ratio, 2.32; 95% CI, 1.11 to 4.88; P=0.02). Hospitalization for heart failure occurred in 43 patients in the dronedarone group and 24 in the placebo group (hazard ratio, 1.81; 95% CI, 1.10 to 2.99; P=0.02). Conclusions Dronedarone increased rates of heart failure, stroke, and death from cardiovascular causes in patients with permanent atrial fibrillation who were at risk for major vascular events. Our data show that this drug should not be used in such patients.
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| 6. |
- Dong, Wenjing, et al.
(författare)
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All in One Multifunctional Perovskite Material for Next Generation SOFC
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 193, s. 225-230
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional roles of La0.2Sr0.25Ca0.45TiO3 (LSCT) perovskite material as anode, cathode, and electrolyte for low temperature solid oxide fuel cell (LT-SOFC) are discovered for the first time, and have been investigated via electrochemical impedance spectroscopy (EIS) and fuel cell (FC) measurements. LSCT resistance decreases prominently in FC environment as shown in this study. An improved performance was observed by compositing LSCT with samaria doped ceria (SDC) at 550 degrees C when the FC power density increased from tens of mW cm(-2) for the pure LSCT system up to hundreds of mW cm(-2). The improved conductivity of LSCT-SDC composite is highlighted. The multifunctionality of LSCT as cathode, anode and electrolyte could be attributed to different conducting behavior at high and low oxygen partial pressures and ionic conduction at intermediate oxygen partial pressures. These new discoveries not only indicate great potential for exploring multifunctional perovskites for the next generation SOFC, but also deepen SOFC science and develop new technologies.
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| 7. |
- Fox, Keith A., et al.
(författare)
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Influence of renal function on the efficacy and safety of fondaparinux relative to enoxaparin in non-ST-segment elevation acute coronary syndromes
- 2007
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Ingår i: Annals of Internal Medicine. - 0003-4819 .- 1539-3704. ; 147:5, s. 304-310
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A recent randomized, controlled trial, the Fifth Organization to Assess Strategies in Acute Ischemic Syndromes (OASIS 5) trial, reported that major bleeding was 2-fold less frequent with fondaparinux than with enoxaparin in acute coronary syndromes (ACS). Renal dysfunction increases the risk for major bleeding. OBJECTIVE: To compare the efficacy and safety of fondaparinux and enoxaparin over the spectrum of renal dysfunction observed in the OASIS 5 trial. DESIGN: Subgroup analysis of a randomized, controlled trial. SETTING: Patients presenting to the hospital with non-ST-segment elevation ACS. PATIENTS: 19,979 of the 20,078 patients in the OASIS 5 trial in whom creatinine was measured at baseline. MEASUREMENTS: Death, myocardial infarction, refractory ischemia, and major bleeding were evaluated separately and as a composite end point at 9, 30, and 180 days. Glomerular filtration rate (GFR) was calculated by using the Modification of Diet in Renal Disease formula. RESULTS: The absolute differences in favor of fondaparinux (efficacy and safety) were most marked in patients with a GFR less than 58 mL/min per 1.73 m2; the largest differences occurred in major bleeding events. At 9 days, death, myocardial infarction, or refractory ischemia occurred in 6.7% of patients receiving fondaparinux and 7.4% of those receiving enoxaparin (hazard ratio, 0.90 [95% CI, 0.73 to 1.11]); major bleeding occurred in 2.8% and 6.4%, respectively (hazard ratio, 0.42 [CI, 0.32 to 0.56]). Statistically significant differences in major bleeding persisted at 30 and 180 days. The rates of the composite end point were lower with fondaparinux than with enoxaparin in all quartiles of GFR, but the differences were statistically significant only among patients with a GFR less than 58 mL/min per 1.73 m2. Limitations: Subgroup analyses warrant caution; the study was powered to detect noninferiority at 9 days. Fondaparinux is not approved for use in patients with ACS in the United States. CONCLUSIONS: The benefits of fondaparinux over enoxaparin when administered for non-ST-segment elevation ACS are most marked among patients with renal dysfunction and are largely explained by lower rates of major bleeding with fondaparinux.
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| 8. |
- Mehta, Shamir R., et al.
(författare)
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Efficacy and safety of fondaparinux versus enoxaparin in patients with acute coronary syndromes undergoing percutaneous coronary intervention : results from the OASIS-5 trial
- 2007
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 50:18, s. 1742-1751
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study reports a prospectively planned analysis of patients with acute coronary syndrome who underwent early percutaneous coronary intervention (PCI) in the OASIS-5 (Fifth Organization to Assess Strategies in Ischemic Syndromes) trial. BACKGROUND: In the OASIS-5 trial, fondaparinux was similar to enoxaparin for short-term efficacy, but reduced major bleeding by one-half and 30-day mortality by 17%. METHODS: The OASIS-5 trial was a double-blind, randomized comparison of fondaparinux and enoxaparin in 20,078 patients with acute coronary syndrome. A total of 12,715 patients underwent heart catheterization during the initial hospitalization, and 6,238 patients underwent PCI. In the fondaparinux group, intravenous fondaparinux was given for PCI. In the enoxaparin group, no additional anticoagulant was given if PCI was <6 h from last subcutaneous dose, and additional intravenous unfractionated heparin (UFH) was given if PCI was >6 h. RESULTS: Fondaparinux compared with enoxaparin reduced major bleeding by more than one-half (2.4% vs. 5.1%, hazard ratio [HR] 0.46, p < 0.00001) at day 9, with similar rates of ischemic events, resulting in superior net clinical benefit (death, myocardial infarction, stroke, major bleeding: 8.2% vs. 10.4%, HR 0.78, p = 0.004). Fondaparinux reduced major bleeding 48 h after PCI irrespective of whether PCI was performed <6 h of the last enoxaparin dose (1.6% vs. 3.8%, HR 0.42, p < 0.0001) or >6 h when UFH was given (1.3% vs. 3.4%, HR 0.39, p < 0.0001). Catheter thrombus was more common in patients receiving fondaparinux (0.9%) than enoxaparin alone (0.4%), but was largely prevented by using UFH at the time of PCI, without any increase in bleeding. CONCLUSIONS: Upstream therapy with fondaparinux compared with upstream enoxaparin substantially reduces major bleeding while maintaining efficacy, resulting in superior net clinical benefit. The use of standard UFH in place of fondaparinux at the time of PCI seems to prevent angiographic complications, including catheter thrombus, without compromising the benefits of upstream fondaparinux.
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| 9. |
- Mi, Youquan, et al.
(författare)
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Experimental and physical approaches on a novel semiconducting-ionic membrane fuel cell
- 2018
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 43:28, s. 12756-12764
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Tidskriftsartikel (refereegranskat)abstract
- Semiconducting-ionic membranes (SIMs) have exhibited significant superiority to replace the conventional ionic electrolytes in solid oxide fuel cells (SOFCs). One interesting phenomenon is that the SIMs can successfully avoid the underlying short-circuiting issue and power losses while bringing significantly enhanced power output. It is crucial to understand the physics in such devices as they show distinct electrochemical processes with conventional fuel cells. We first presented experimental studies of a SIM fuel cell based on a composite of semiconductor LiCo0.8Fe0.2O2 (LCF) and ionic conductor Sm-doped CeO2 (SDC), which achieved a remarkable power density of 1150 mW cm(-2) at 550 degrees C along with a high open circuit voltage (OCV) of 1.04 V. Then, for the first time we used a physical model via combining a semiconductor-ionic contact junction with a rectifying layer which blocks the electron leakage to describe such unique SIM device and excellent performance. Current and power are the most important characteristics for the device, by introducing the rectifying layer we described the SIM physical nature and new device process. This work presented a new view on advanced SIM SOFC science and technology from physics.
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| 10. |
- Mushtaq, Naveed, et al.
(författare)
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Tuning the Energy Band Structure at Interfaces of the SrFe0.75Ti0.25O3-delta-Sm0.25Ce0.75O2-delta Heterostructure for Fast Ionic Transport
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:42, s. 38737-38745
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Tidskriftsartikel (refereegranskat)abstract
- Interface engineering holds huge potential for enabling exceptional physical properties in heterostructure materials via tuning properties at the atomic level. In this study, a heterostructure built by a new redox stable semiconductor SrFe0.75Ti0.25O3-delta (SFT) and an ionic conductor Sm0.25Ce0.75O2 (SDC) is reported. The SFT-SDC heterostructure exhibits a high ionic conductivity >0.1 S/cm at 520 degrees C, which is 1 order of magnitude higher than that of bulk SDC. When it was applied into the fuel cell, the SFT-SDC can realize favorable electrolyte functionality and result in an excellent power density of 920 mW cm(-2) at 520 degrees C. The prepared SFT-SDC heterostructure materials possess both electronic and ionic conduction, where electron states modulate local electrical field to facilitate ion transport. Further investigations to calculate the structure and electronic structure/state of SFT and SDC are done using density functional theory (DFT). It is found that the reconstruction of the energy band at interfaces is responsible for such enhanced ionic conductivity and cell power output. The current study about the perovskite-based heterostructure presents a novel strategy for developing advanced ceramic fuel cells.
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