| 1. |
- Kasner, Scott E., et al.
(författare)
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Characterization of Patients with Embolic Strokes of Undetermined Source in the NAVIGATE ESUS Randomized Trial
- 2018
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Ingår i: Journal of Stroke and Cerebrovascular Diseases. - : Elsevier BV. - 1052-3057. ; 27:6, s. 1673-1682
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Tidskriftsartikel (refereegranskat)abstract
- Background: The New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial vs. ASA to Prevent Embolism in Embolic Stroke of Undetermined Source (NAVIGATE-ESUS) trial is a randomized phase-III trial comparing rivaroxaban versus aspirin in patients with recent ESUS. Aims: We aimed to describe the baseline characteristics of this large ESUS cohort to explore relationships among key subgroups. Methods: We enrolled 7213 patients at 459 sites in 31 countries. Prespecified subgroups for primary safety and efficacy analyses included age, sex, race, global region, stroke or transient ischemic attack prior to qualifying event, time to randomization, hypertension, and diabetes mellitus. Results: Mean age was 66.9 ± 9.8 years; 24% were under 60 years. Older patients had more hypertension, coronary disease, and cancer. Strokes in older subjects were more frequently cortical and accompanied by radiographic evidence of prior infarction. Women comprised 38% of participants and were older than men. Patients from East Asia were oldest whereas those from Latin America were youngest. Patients in the Americas more frequently were on aspirin prior to the qualifying stroke. Acute cortical infarction was more common in the United States, Canada, and Western Europe, whereas prior radiographic infarctions were most common in East Asia. Approximately forty-five percent of subjects were enrolled within 30 days of the qualifying stroke, with earliest enrollments in Asia and Eastern Europe. Conclusions: NAVIGATE-ESUS is the largest randomized trial comparing antithrombotic strategies for secondary stroke prevention in patients with ESUS. The study population encompasses a broad array of patients across multiple continents and these subgroups provide ample opportunities for future research.
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| 2. |
- Wu, Junru, et al.
(författare)
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Unique tridentate coordination tailored solvation sheath towards highly stable lithium metal batteries
- 2023
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Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 35:38
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Tidskriftsartikel (refereegranskat)abstract
- Electrolyte optimization by solvent molecule design has been recognized as an effective approach for stabilizing lithium (Li) metal batteries. However, the coordination pattern of Li+ with solvent molecules has been sparsely considered. Here, we report an electrolyte design strategy based on bi/tridentate chelation of Li+ and solvent to tune the solvation structure. As a proof of concept, a novel solvent with multi oxygen coordination sites is demonstrated to facilitate the formation of an anion-aggregated solvation shell, enhancing the interfacial stability and de-solvation kinetics. As a result, the as-developed electrolyte exhibits ultra-stable cycling over 1400 h in symmetric cells with 50 ?m-thin Li foils. When paired with high-loading LiFePO4, full cells maintain 92% capacity over 500 cycles and deliver improved electrochemical performances over a wide temperature range from -10 °C to 60 °C. Furthermore, the concept is validated in a pouch cell (570 mAh), achieving a capacity retention of 99.5% after 100 cycles. This brand-new insight on electrolyte engineering provides guidelines for practical high-performance Li metal batteries. This article is protected by copyright. All rights reserved
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| 3. |
- Chen, Chunyu, et al.
(författare)
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Equilibrium of Frequency Control Ancillary Service Market Based on Attack-defense Game
- 2024
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Ingår i: Dianwang Jishu/Power System Technology. - : Power System Technology Press. - 1000-3673. ; 48:2, s. 679-687
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Tidskriftsartikel (refereegranskat)abstract
- With the improvement of electricity market rules, the power system operator permits new energy resources to gradually participate in the frequency control ancillary service market. The participation of new energy resources greatly enhance the frequency regulation performance and mutual support of different energy resources. However, some frequency regulation resources are usually equipped with insufficient cyber security protection measures due to economic considerations. Under this situation, hackers may exploit the vulnerability of susceptible cyber physical systems to disrupt the operation of frequency control ancillary service market. Therefore, we analyze frequency modulation market game equilibrium considering the attack-defense game. First, we analyze the cyber attack behaviors aiming at manipulating the bidding information of susceptible resources. Second, we analyze the attack model aiming at maximizing the profit of the complicity. Next, a frequency modulation market equilibrium model considering the master-slave Stackelberg game of both sides of attack and defense is designed. Finally, the frequency modulation market equilibrium results based on the Column-and-Constraint Generation (C&CG) algorithm are analyzed. Through case analysis of 30-unit frequency regulation markets, the average deviation of capacity revenue change from 113.89% under attack to 12.56% after defense, indicating that the defender can to a certain extent suppress the market equilibrium deviation caused by the attacker.
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| 4. |
- Hart, Robert G., et al.
(författare)
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Rivaroxaban for secondary stroke prevention in patients with embolic strokes of undetermined source : Design of the NAVIGATE ESUS randomized trial
- 2016
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Ingår i: European Stroke Journal. - : SAGE Publications. - 2396-9873 .- 2396-9881. ; 1:3, s. 146-154
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Tidskriftsartikel (refereegranskat)abstract
- Background: Embolic strokes of undetermined source comprise up to 20% of ischemic strokes. The stroke recurrence rate is substantial with aspirin, widely used for secondary prevention. The New Approach riVaroxaban Inhibition of Factor Xa in a Global trial versus ASA to prevenT Embolism in Embolic Stroke of Undetermined Source international trial will compare the efficacy and safety of rivaroxaban, an oral factor Xa inhibitor, versus aspirin for secondary prevention in patients with recent embolic strokes of undetermined source. Main hypothesis: In patients with recent embolic strokes of undetermined source, rivaroxaban 15 mg once daily will reduce the risk of recurrent stroke (both ischemic and hemorrhagic) and systemic embolism (primary efficacy outcome) compared with aspirin 100 mg once daily. Design: Double-blind, randomized trial in patients with embolic strokes of undetermined source, defined as nonlacunar cryptogenic ischemic stroke, enrolled between seven days and six months from the qualifying stroke. The planned sample size of 7000 participants will be recruited from approximately 480 sites in 31 countries between 2014 and 2017 and followed for a mean of about two years until at least 450 primary efficacy outcome events have occurred. The primary safety outcome is major bleeding. Two substudies assess (1) the relative effect of treatments on MRI-determined covert brain infarcts and (2) the biological underpinnings of embolic strokes of undetermined source using genomic and biomarker approaches. Summary: The New Approach riVaroxaban Inhibition of Factor Xa in a Global trial versus ASA to prevenT Embolism in Embolic Stroke of Undetermined Source trial is evaluating the benefits and risks of rivaroxaban for secondary stroke prevention in embolic strokes of undetermined source patients. Main results are anticipated in 2018.
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| 5. |
- Li, Wei, et al.
(författare)
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Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations
- 2017
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 14:22, s. 5053-5067
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Tidskriftsartikel (refereegranskat)abstract
- The use of dynamic global vegetation models (DGVMs) to estimate CO2 emissions from land-use and land-cover change (LULCC) offers a new window to account for spatial and temporal details of emissions and for ecosystem processes affected by LULCC. One drawback of LULCC emissions from DGVMs, however, is lack of observation constraint. Here, we propose a new method of using satellite-and inventory-based biomass observations to constrain historical cumulative LULCC emissions (E-LUC(c)) from an ensemble of nine DGVMs based on emerging relationships between simulated vegetation biomass and E-LUC(c). This method is applicable on the global and regional scale. The original DGVM estimates of E-LUC(c) range from 94 to 273 PgC during 1901-2012. After constraining by current biomass observations, we derive a best estimate of 155 +/- 50 PgC (1 sigma Gaussian error). The constrained LULCC emissions are higher than prior DGVM values in tropical regions but significantly lower in North America. Our emergent constraint approach independently verifies the median model estimate by biomass observations, giving support to the use of this estimate in carbon budget assessments. The uncertainty in the constrained Ec LUC is still relatively large because of the uncertainty in the biomass observations, and thus reduced uncertainty in addition to increased accuracy in biomass observations in the future will help improve the constraint. This constraint method can also be applied to evaluate the impact of land-based mitigation activities.
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| 6. |
- Wang, Ying, et al.
(författare)
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A tri-level programming-based frequency regulation market equilibrium under cyber attacks
- 2023
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Ingår i: Protection and Control of Modern Power Systems. - : Springer Nature. - 2367-2617 .- 2367-0983. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Owing to their flexibility and rapid response, grid-connected distributed energy resources (DERs) are wielding growing influence in frequency regulation markets (FRMs). Nevertheless, compared with conventional large-scale generators, small-scale DERs are usually weakly shielded by cyber security measures. This offers attackers the opportunity of disrupting the clearing and settlement of FRMs by manipulating the bid information of DERs. In this paper, the frequency regulation market equilibrium is studied considering the dynamic gaming between attackers and defenders, both of which need the knowledge of FRMs for their interventions. Specifically, a tri-level programming model characterizing the attacker–defender–operator (ADO) interdiction problem in FRMs is developed and then analyzed using a column and constraint generation algorithm, thereby achieving market equilibrium representing the defender's best response to the attacker. The defense strategy in the market equilibrium can attenuate the negative influence of cyber attacks upon the FRMs to the maximum extent. Finally, based on the operating rules of the California Independent System Operator, the FRM process considering the ADO interdiction is simulated and the numerical equilibrium results are presented.
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| 7. |
- Wang, Yilong, et al.
(författare)
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Breakdown characteristics of nitrogen at different pressures in alternating non-uniform electric fields
- 2023
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Ingår i: Physica Scripta. - 1402-4896 .- 0031-8949. ; 98:12
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Tidskriftsartikel (refereegranskat)abstract
- ACbreakdown characteristics of nitrogen at different pressures in electric fields with different degrees of non-uniformity provided by a sphere-plane electrode system have been investigated. It is found that the measured breakdown voltages obey Paschen’s law at the values of the field factor (the ration of the maximum field strength between electrodes to the average field strength) below∼2. Deviations start to appear and increase gradually if the field factor increases above this threshold. Respectively, the dependence of the breakdown voltageUb on the product of pressure p and gap distance d changes from been linearUb∼p×d to a more complex relationship of typeUb∼p×ln(d). It is found that the maximum field strength corresponding to the breakdown increases with increasing gas pressure and decreasing electrode radius but it is independent on the gap distance. The breakdown voltages predicted by the streamer criterion agree well with the experimental data. The results obtained for nitrogen were compared with the breakdown characteristics of air and it was found that at the values of the field factor below 9, the breakdown strength of nitrogen was higher than that of ambient air.
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