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| 2. |
- Reddy, A. Satyanarayana, et al.
(författare)
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Ultrathin titania coating for high-temperature stable SiO(2)/Pt nanocatalysts
- 2011
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 47, s. 8412-8414
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Tidskriftsartikel (refereegranskat)abstract
- The facile synthesis of silica supported platinum nanoparticles with ultrathin titania coating to enhance metal-support interactions suitable for high temperature reactions is reported, as thermal and structure stability of metal nanoparticles is important for catalytic reactions.
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| 3. |
- Cheon, Jae Yeong, et al.
(författare)
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Ordered mesoporous porphyrinic carbons with very high electrocatalytic activity for the oxygen reduction reaction
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 2715-
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Tidskriftsartikel (refereegranskat)abstract
- The high cost of the platinum-based cathode catalysts for the oxygen reduction reaction (ORR) has impeded the widespread application of polymer electrolyte fuel cells. We report on a new family of non-precious metal catalysts based on ordered mesoporous porphyrinic carbons (M-OMPC; M = Fe, Co, or FeCo) with high surface areas and tunable pore structures, which were prepared by nanocasting mesoporous silica templates with metalloporphyrin precursors. The FeCo-OMPC catalyst exhibited an excellent ORR activity in an acidic medium, higher than other non-precious metal catalysts. It showed higher kinetic current at 0.9 V than Pt/C catalysts, as well as superior long-term durability and MeOH-tolerance. Density functional theory calculations in combination with extended X-ray absorption fine structure analysis revealed a weakening of the interaction between oxygen atom and FeCo-OMPC compared to Pt/C. This effect and high surface area of FeCo-OMPC appear responsible for its significantly high ORR activity.
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| 4. |
- Choi, Joong Il Jake, et al.
(författare)
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Atomic-scale view of stability and degradation of single-crystal MAPbBr(3) surfaces
- 2019
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 7:36, s. 20760-20766
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Tidskriftsartikel (refereegranskat)abstract
- While organic-inorganic hybrid perovskite solar cells are emerging as promising candidates for next-generation solar cells with fascinating power conversion efficiency, the instability of perovskites remains a significant bottleneck for their commercialization. An atomic scale understanding of the degradation of hybrid perovskites, however, is only in its beginning stages because of the difficulty in preparing well-defined surface conditions for characterization. Using atomic force microscopy at ultra-high vacuum and room temperature, we report the first direct observation of the degradation process of a cleaved methylammonium lead bromide, MAPbBr(3) (MA: CH3NH3+), single crystal. Upon in situ cleavage, atomic force microscopy images show large flat terraces with monolayer height steps, which correspond to the surface of cubic MAPbBr(3) with methylammonium ligand termination. While this surface can be prepared via the cleavage process and is energetically stable, we observe that after several weeks under dark and vacuum conditions it degrades and produces clusters surrounded by pits. Guided by density functional theory calculations, we propose a degradation pathway that initiates even at low humidity levels and leads to the formation of surface PbBr2 species. We finally identify the electronic structure of the MA-bromine-terminated flat surface and find that it is correlated with a strong field-induced degradation of the MAPbBr(3) only at positive sample bias voltages.
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| 5. |
- Choi, Joong Il Jake, et al.
(författare)
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Surface Termination-Dependent Nanotribological Properties of Single-Crystal MAPbBr(3) Surfaces
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:2, s. 1484-1491
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Tidskriftsartikel (refereegranskat)abstract
- Atomistic characterization of surface termination and the corresponding mechanical properties of single-crystal methylammonium lead tribromide (MAPbBr(3)) are performed using combined atomic force microscopy (AFM) measurements and density functional theory (DFT) calculations. A clean MAPbBr(3) surface is obtained by in situ cleavage in ultrahigh vacuum at room temperature, and the subsequent AFM measurements of the as-cleaved MAPbBr(3) exhibit the coexistence of two different surface terrace types with step height differences corresponding to about half the thickness of a PbI6 octahedron layer. Concurrent friction force microscopy measurements show that the two surfaces result in two distinct friction values. Based on DFT calculations, we attribute the higher-friction and lower-friction surfaces to MABr-terminated flat and PbBr2-terminated vacant surface terminations, respectively. The calculated electronic band structures of the various MABr- and PbBr2-terminated surfaces show that the midgap states are absent, revealing the defect-tolerant nature of the ideal single-crystal MAPbBr(3) surfaces.
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| 6. |
- Haas, Brian J., et al.
(författare)
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Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans
- 2009
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 461:7262, s. 393-398
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Tidskriftsartikel (refereegranskat)abstract
- Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement(1). To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the world's population(1). Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion(2). Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars(3,4). Here we report the sequence of the P. infestans genome, which at similar to 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for similar to 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
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| 9. |
- Kubica, Jacek, et al.
(författare)
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Prolonged antithrombotic therapy in patients after acute coronary syndrome : A critical appraisal of current European Society of Cardiology guidelines
- 2020
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Ingår i: CARDIOLOGY JOURNAL. - : VM Media SP. zo.o VM Group SK. - 1897-5593 .- 1898-018X. ; 27:6, s. 661-676
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Tidskriftsartikel (refereegranskat)abstract
- The increased risk of non-cardiovascular death in patients receiving clopidogrel or prasugrel in comparison with the placebo group in the Dual Antiplatelet Therapy (DAPT) trial in contrast to the decreased risk of cardiovascular death and all-cause death seen in patients treated with low-dose ticagrelor in the EU label population of the PEGASUS-TIMI 54 trial, resulted in inclusion in the 2020 ESC NSTE-ACS guidelines the recommendation for use of clopidogrel or prasugrel only if the patient is not eligible for treatment with ticagrelor. The prevalence of the primary outcome composed of cardiovascular death, stroke, or myocardial infarction was lower in the low-dose rivaroxaban and acetylsalicylic acid (ASA) group than in the ASA-alone group in the COMPASS trial. Moreover, all-cause mortality and cardiovascular mortality rates were lower in the rivaroxaban-plus-ASA group. Comparison of the PEGASUS-TIMI 54 and COMPASS trial patient characteristics clearly shows that each of these treatment strategies should be addressed at different groups of patients. A greater benefit in post-acute coronary syndrome (ACS) patients with a high risk of ischemic events and without high bleeding risk may be expected with ASA and ticagrelor 60 mg b.i.d. when the therapy is continued without interruption or with short interruption only after ACS. On the other hand, ASA and rivaroxaban 2.5 mg b.i.d. seems to be a better option when indications for dual antithrombotic therapy (DATT) appear after a longer time from ACS (more than 2 years) and/or from cessation of DAPT (more than 1 year) and in patients with multiple vascular bed atherosclerosis. Thus, both options of DATTs complement each other rather than compete, as can be presumed from the recommendations. However, a direct comparison between these strategies should be tested in future clinical trials.
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| 10. |
- Navarese, Eliano Pio, et al.
(författare)
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Drug-coated balloons in treatment of in-stent restenosis : a meta-analysis of randomised controlled trials
- 2013
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Ingår i: Clinical Research in Cardiology. - : Springer Science and Business Media LLC. - 1861-0684 .- 1861-0692. ; 102:4, s. 279-287
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Drug-coated balloons (DCBs) have been developed for the percutaneous treatment of coronary artery disease. An initial focus has been the management of in-stent restenosis (ISR) but randomised controlled trials (RCTs) have been small and powered only for angiographic endpoints.OBJECTIVE:The aim of the work was to assess the clinical and angiographic outcomes of patients treated for ISR with DCB versus control (balloon angioplasty or drug-eluting stents) by a meta-analysis of RCTs.METHODS: A comprehensive search was performed of RCTs where patients with ISR were randomly assigned to either DCB or alternative coronary intervention. Outcome measurements were death, myocardial infarction (MI), target lesion revascularisation (TLR), binary definition of restenosis and in-lesion late luminal loss (LLL).RESULTS: Four studies were identified that fulfilled the inclusion criteria. Pooled odds ratios (ORs) were calculated for patients treated for ISR (n = 399). Mean follow-up duration was 14.5 months. DCBs were associated with lower rates of TLR [8.8 vs. 29.7 % OR (95 % confidence interval, CI) 0.20 (0.11-0.36), p < 0.0001], binary restenosis [10.3 vs. 41.3 % OR (95 % CI) 0.13 (0.07-0.24), p < 0.00001] and MI [0.5 vs. 3.8 %, OR (95 % CI) 0.21 (0.04-1.00), p = 0.05]. No significant heterogeneity was identified.CONCLUSION: Drug-coated balloons appear to be effective versus control in reducing TLR and possibly MI versus balloon angioplasty or drug-eluting stents in the management of ISR.
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