| 1. |
- Gu, Y, et al.
(författare)
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Quick Hot Shot & Young Surgeon Presentation
- 2015
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Ingår i: Hernia : the journal of hernias and abdominal wall surgery. - 1248-9204. ; 19 Suppl 1, s. S77-84
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- Segev, Gideon, et al.
(författare)
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The 2022 solar fuels roadmap
- 2022
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 55:32
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Tidskriftsartikel (refereegranskat)abstract
- Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.
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| 4. |
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| 5. |
- Ertem, Mehmed Z., et al.
(författare)
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N-O bond cleavage mechanism(s) in nitrous oxide reductase
- 2012
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer Science and Business Media LLC. - 0949-8257 .- 1432-1327. ; 17:5, s. 687-698
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Tidskriftsartikel (refereegranskat)abstract
- Quantum chemical calculations of active-site models of nitrous oxide reductase (N2OR) have been undertaken to elucidate the mechanism of N-O bond cleavage mediated by the supported tetranuclear Cu4S core (Cu-Z) found in the enzymatic active site. Using either a minimal model previously employed by Gorelsky et al. (J. Am. Chem. Soc. 128:278-290, 2006) or a more extended model including key residue side chains in the active-site second shell, we found two distinct mechanisms. In the first model, N2O binds to the fully reduced Cu-Z in a bent mu-(1,3)-O,N bridging fashion between the Cu-I and Cu-IV centers and subsequently extrudes N-2 while generating the corresponding bridged mu-oxo species. In the second model, substrate N2O binds loosely to one of the coppers of Cu-Z in a terminal fashion, i.e., using only the oxygen atom; loss of N-2 generates the same mu-oxo copper core. The free energies of activation predicted for these two alternative pathways are sufficiently close to one another that theory does not provide decisive support for one over the other, posing an interesting problem with respect to experiments that might be designed to distinguish between the two. Effects of nearby residues and active-site water molecules are also explored.
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| 6. |
- Huber, Stefan M., et al.
(författare)
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Generating Cu-II-oxyl/Cu-III-oxo species from Cu-I-alpha-ketocarboxylate complexes and O-2 : in silico studies on ligand effects and C-H-activation reactivity.
- 2009
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 15:19, s. 4886-4895
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Tidskriftsartikel (refereegranskat)abstract
- A mechanism for the oxygenation of Cu-I complexes with alpha-keto-carboxylate ligands that is based on a combination of density functional theory and multireference second-order perturbation theory (CASSCF/CASPT2) calculations is elaborated. The reaction proceeds in a manner largely analogous to those of similar Fe-II-alpha-ketocarboxylate systems, that is, by initial attack of a coordinated oxygen molecule on a ketocarboxylate ligand with concomitant decarboxylation. Subsequently, two reactive intermediates may be generated, a Cu-peracid structure and a [CuO](+) species, both of which are capable of oxidizing a phenyl ring component of the supporting ligand. Hydroxylation by the [CuO](+) species is predicted to proceed with a smaller activation free energy. The effects of electronic and steric variations on the oxygenation mechanisms were studied by introducing substituents at several positions of the ligand backbone and by investigating various N-donor ligands. In general, more electron donation by the N-donor ligand leads to increased stabilization of the more Cu-II/Cu-III-like intermediates (oxygen adducts and [CuO](+) species) relative to the more Cu-I-like peracid intermediate. For all ligands investigated the [CuO](+) intermediates are best described as Cu-II-O center dot(-) species with triplet ground states. The reactivity of these compounds in C-H abstraction reactions decreases with more electron-donating N-donor ligands, which also increase the Cu-O bond strength, although the Cu-O bond is generally predicted to be rather weak (with a bond order of about 0.5). A comparison of several methods to obtain singlet energies for the reaction intermediates indicates that multireference second-order perturbation theory is likely more accurate for the initial oxygen adducts, but not necessarily for subsequent reaction intermediates.
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