Wright v. Universal Maritime Service Corp.

Published in cooperation with the American Bar Association Section of Dispute Resolutio

Modelling the coordination environment in α‐ketoglutarate dependent oxygenases – a comparative study on the effect of N‐ vs. O‐ligation

In various non-heme iron oxygenases the Fe(II) center is coordinated by 2 N and 1 O atoms of the 2-His-2-carboxylate facial triad; however, most artificial model complexes bear only N-based ligands. In an effort to closely mimic the coordination environment in α-ketoglutarate dependent oxygenases, we have now employed the Me2tacnO ligand (4,7-dimethyl-1-oxa-4,7-diazacyclononane) in the synthesis of the complexes [(Me2tacnO)FeCl2]2 (1-NNO), [(Me2tacnO)FeCl3] (1 b-NNO) and [(Me2tacnO)Fe(BF)Cl] (2-NNO; BF=benzoylformate). The weaker donation of the O atom in the ligand was found to result in stronger binding of the ligand in trans-position to the O-atom of the ancillary ligand as compared to the corresponding complexes involving the Me3tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) ligand. Furthermore, by stopped-flow techniques we could detect an intermediate (3-NNO) in the reaction of 2-NNO with O2. The spectroscopic features of 3-NNO agree with the involvement of an Fe(IV)-oxo intermediate and hence this study represents the first detection of such an intermediate in the O2 activation of artificial α-ketoglutarate Fe(II) complexes.Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)Peer Reviewe

Modelling the coordination environment in α-ketoglutarate dependent oxygenases – a comparative study on the effect of N- vs. O-ligation

In various non-heme iron oxygenases the Fe(II) center is coordinated by 2 N and 1 O atoms of the 2-His-2-carboxylate facial triad; however, most artificial model complexes bear only N-based ligands. In an effort to closely mimic the coordination environment in α-ketoglutarate dependent oxygenases, we have now employed the Me2tacnO ligand (4,7-dimethyl-1-oxa-4,7-diazacyclononane) in the synthesis of the complexes [(Me2tacnO)FeCl2]2 (1-NNO), [(Me2tacnO)FeCl3] (1 b-NNO) and [(Me2tacnO)Fe(BF)Cl] (2-NNO; BF=benzoylformate). The weaker donation of the O atom in the ligand was found to result in stronger binding of the ligand in trans-position to the O-atom of the ancillary ligand as compared to the corresponding complexes involving the Me3tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) ligand. Furthermore, by stopped-flow techniques we could detect an intermediate (3-NNO) in the reaction of 2-NNO with O2. The spectroscopic features of 3-NNO agree with the involvement of an Fe(IV)-oxo intermediate and hence this study represents the first detection of such an intermediate in the O2 activation of artificial α-ketoglutarate Fe(II) complexes

Assessing a commercially available sports drink on exogenous carbohydrate oxidation, fluid delivery and sustained exercise performance

Background: Whilst exogenous carbohydrate oxidation (CHOEXO) is influenced by mono- and disaccharide combinations, debate exists whether such beverages enhance fluid delivery and exercise performance. Therefore, this study aimed to ascertain CHOEXO, fluid delivery and performance times of a commercially available maltodextrin/ fructose beverage in comparison to an isocaloric maltodextrin beverage and placebo. Methods: Fourteen club level cyclists (age: 31.79 ± 10.02 years; height: 1.79 ± 0.06 m; weight: 73.69 ± 9.24 kg; VO2max: 60.38 ± 9.36 mL · kg·-1 min−1) performed three trials involving 2.5 hours continuous exercise at 50% maximum power output (Wmax: 176.71 ± 25.92 W) followed by a 60 km cycling performance test. Throughout each trial, athletes were randomly assigned, in a double-blind manner, either: (1) 1.1 g · min−1 maltodextrin + 0.6 g · min−1 fructose (MD + F), (2) 1.7 g · min−1 of maltodextrin (MD) or (3) flavoured water (P). In addition, the test beverage at 60 minutes contained 5.0 g of deuterium oxide (2H2O) to assess quantification of fluid delivery. Expired air samples were analysed for CHOEXO according to the 13C/12C ratio method using gas chromatography continuous flow isotope ratio mass spectrometry. Results: Peak CHOEXO was significantly greater in the final 30 minutes of submaximal exercise with MD + F and MD compared to P (1.45 ± 0.09 g · min−1, 1.07 ± 0.03 g · min−1and 0.00 ± 0.01 g · min−1 respectively, P < 0.0001), and significantly greater for MD + F compared to MD (P = 0.005). The overall appearance of 2H2O in plasma was significantly greater in both P and MD + F compared to MD (100.27 ± 3.57 ppm, 92.57 ± 2.94 ppm and 78.18 ± 4.07 ppm respectively, P < 0.003). There was no significant difference in fluid delivery between P and MD + F (P = 0.078). Performance times significantly improved with MD + F compared with both MD (by 7 min 22 s ± 1 min 56 s, or 7.2%) and P (by 6 min 35 s ± 2 min 33 s, or 6.5%, P < 0.05) over 60 km. Conclusions: A commercially available maltodextrin-fructose beverage improves CHOEXO and fluid delivery, which may benefit individuals during sustained moderate intensity exercise. The greater CHOEXO observed when consuming a maltodextrin-fructose beverage may support improved performance times

Theoretical Study of Oxocyclohexadienylidene Isomers: Electronic Structures and Molecular Properties

The molecular properties and electronic structures for three isomers of oxocyclohexadienylidene were investigated using multiconfiguration SCF (MCSCF) wave functions. The ground electronic states of the ortho and para isomers are the open shell triplet, whereas the meta isomer has a singlet ground state with significant open shell character. The structural features of the ground states of all three isomers are close to the quinoid type structure. Several molecular properties such as the electron spin density, electron affinity (EA), acidity and bond dissociation energy for the three isomers and/or their corresponding radicals are also considered and are compared with experimental values. In particular, the MCSCF(8,8)/6-31+G* electron spin densities for both ortho and para isomers are very close to the experimental values of the phenoxyl radical

Thirteen-Year Follow-up of Optic Disc Hemorrhages in the Ocular Hypertension Treatment Study

To determine the cumulative incidence of optic disc hemorrhage (ODH) before and after development of primary open angle glaucoma (POAG); determine the prognostic significance of ODH for the development of POAG; identify predictive factors for ODH

α,2-, α,3-, and α,4-Dehydrophenol Radical Anions: Formation, Reactivity, and Energetics Leading to the Heats of Formation of α,2-, α,3-, and α,4-Oxocyclohexadienylidene

We have regiospecifically generated the α,2-, α,3-, and α,4-dehydrophenoxide anions by collisional activation of o-, m-, and p-nitrobenzoate. The α,2 and α,4 isomers also were synthesized by reacting o-benzyne radical anion with carbon dioxide and electron ionization ofp-diazophenol. All three dehydrophenol radical anions were differentiated from each other and identified by probing their chemical reactivity with several reagents. Each isomer was converted to phenoxide and its corresponding quinone as well. Thermochemical measurements were carried out on all three radical anions and their hydrogen-atom affinities, proton affinities, and electron binding energies are reported. These measured quantities are combined in thermodynamic cycles to derive the heats of formation of each of the radical anions and their corresponding carbenes (i.e., α,2-, α,3-, and α,4-dehydrophenol). These results are compared to MCQDPT2, G3, G2+(MP2), and B3LYP calculations and experimental data for appropriate reference compounds