| 1. |
- Alvarez-Madrazo, Samantha, et al.
(författare)
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Common Polymorphisms in the CYP11B1 and CYP11B2 Genes: Evidence for a Digenic Influence on Hypertension
- 2013
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Ingår i: Hypertension. - 1524-4563. ; 61:1, s. 232-239
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Tidskriftsartikel (refereegranskat)abstract
- The locus encompassing the corticosteroidogenic genes CYP11B2 and CYP11B1 is of potential importance in essential hypertension. We analyzed the association of polymorphisms at this locus with risk of essential hypertension, using 2 white case-control collections for discovery (n = 3340) and confirmation (n = 2929). Single-marker and haplotype analyses were performed, with the CYP11B2 Intron 2 Conversion polymorphism showing strongest association with hypertension in both cohorts and in combined analysis (odds ratio = 1.16, P = 8.54x10(-5)). The CYP11B1 ACA haplotype associated with increased risk of hypertension relative to the alternative, GTC (odds ratio = 1.11; P = 7.4x10(-3)), whereas the CYP11B2 TWtC haplotype seemed protective relative to the contrasting CConvT (odds ratio = 0.88, P = 2.2x10(-3)). Analysis spanning the whole CYP11B1/CYP11B2 locus showed that haplotypes associated with raised risk of hypertension tend to coexist. Functional analysis of heterozygous human adrenal tissue demonstrated decreased CYP11B2 expression and increased CYP11B1 expression for those alleles associating with reduced risk of hypertension. These results confirm the hypertensive influence of this locus, with data suggesting a complex digenic mechanism whereby altered relative CYP11B1 and CYP11B2 gene expression could have a chronic effect on enzyme activity and corticosteroid synthesis. (Hypertension. 2013;61:232-239.). center dot Online Data Supplement
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| 2. |
- Gaccioli, Francesca, et al.
(författare)
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Fetal inheritance of chromosomally integrated human herpesvirus 6 predisposes the mother to pre-eclampsia
- 2020
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Ingår i: Nature Microbiology. - : Springer Nature. - 2058-5276. ; 5:7, s. 901-908
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Tidskriftsartikel (refereegranskat)abstract
- Pre-eclampsia (typically characterized by new-onset hypertension and proteinuria in the second half of pregnancy) represents a major determinant of the global burden of disease1,2. Its pathophysiology involves placental dysfunction, but the mechanism is unclear. Viral infection can cause organ dysfunction, but its role in placentally related disorders of human pregnancy is unknown3. We addressed this using RNA sequencing metagenomics4-6 of placental samples from normal and complicated pregnancies. Here, we show that human herpesvirus 6 (HHV-6, A or B) RNA was detected in 6.1% of cases of pre-eclampsia and 2.2% of other pregnancies. Fetal genotyping demonstrated that 70% of samples with HHV-6 RNA in the placenta exhibited inherited, chromosomally integrated HHV-6 (iciHHV-6). We genotyped 467 pre-eclampsia cases and 3,854 controls and found an excess of iciHHV-6 in the cases (odds ratio of 2.8, 95% confidence intervals of 1.4-5.6, P = 0.008). We validated this finding by comparing iciHHV-6 in a further 740 cases with controls from large-scale population studies (odds ratio of 2.5, 95% confidence intervals of 1.4-4.4, P = 0.0013). We conclude that iciHHV-6 results in the transcription of viral RNA in the human placenta and predisposes the mother to pre-eclampsia.
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| 3. |
- Kwong, Wai Ling, et al.
(författare)
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Cationic Vacancy Defects in Iron Phosphide : A Promising Route toward Efficient and Stable Hydrogen Evolution by Electrochemical Water Splitting
- 2017
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Ingår i: ChemSusChem. - : Wiley-Blackwell. - 1864-5631 .- 1864-564X. ; 10:22, s. 4544-4551
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Tidskriftsartikel (refereegranskat)abstract
- Engineering the electronic properties of transition metal phosphides has shown great effectiveness in improving their intrinsic catalytic activity for the hydrogen evolution reaction (HER) in water splitting applications. Herein, we report for the first time, the creation of Fe vacancies as an approach to modulate the electronic structure of iron phosphide (FeP). The Fe vacancies were produced by chemical leaching of Mg that was introduced into FeP as "sacrificial dopant". The obtained Fe-vacancy-rich FeP nanoparticulate films, which were deposited on Ti foil, show excellent HER activity compared to pristine FeP and Mg-doped FeP, achieving a current density of 10 mAcm(-2) at overpotentials of 108 mV in 1 m KOH and 65 mV in 0.5 m H2SO4, with a near-100% Faradaic efficiency. Our theoretical and experimental analyses reveal that the improved HER activity originates from the presence of Fe vacancies, which lead to a synergistic modulation of the structural and electronic properties that result in a near-optimal hydrogen adsorption free energy and enhanced proton trapping. The success in catalytic improvement through the introduction of cationic vacancy defects has not only demonstrated the potential of Fe-vacancy-rich FeP as highly efficient, earth abundant HER catalyst, but also opens up an exciting pathway for activating other promising catalysts for electrochemical water splitting.
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| 4. |
- Kwong, Wai Ling, et al.
(författare)
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Cobalt- doped hematite thin films for electrocatalytic water oxidation in highly acidic media
- 2019
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Ingår i: Chemical Communications. - : The Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:34, s. 5017-5020
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Tidskriftsartikel (refereegranskat)abstract
- Earth-abundant cobalt-doped hematite thin-film electrocatalysts were explored for acidic water oxidation. The strategically doped hematite produced a stable geometric current density of 10 mA cm(-2) for up to 50 h at pH 0.3, as a result of Co-enhanced intrinsic catalytic activity and charge transport properties across the film matrix.
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| 5. |
- Kwong, Wai Ling, et al.
(författare)
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High-performance iron (III) oxide electrocatalyst for water oxidation in strongly acidic media
- 2018
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Ingår i: Journal of Catalysis. - : Academic Press. - 0021-9517 .- 1090-2694. ; 365, s. 29-35
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Tidskriftsartikel (refereegranskat)abstract
- Stable and efficient oxygen evolution reaction (OER) catalysts for the oxidation of water to dioxygen in highly acidic media are currently limited to expensive noble metal (Ir and Ru) oxides since presently known OER catalysts made of inexpensive earth-abundant materials generally suffer anodic corrosion at low pH. In this study, we report that a mixed-polymorph film comprising maghemite and hematite, prepared using spray pyrolysis deposition followed by low-temperature annealing, showed a sustained OER rate (>24 h) corresponding to a current density of 10 mA cm−2 at an initial overpotential of 650 mV, with a Tafel slope of only 56 mV dec−1 and near-100% Faradaic efficiency in 0.5 M H2SO4 (pH 0.3). This performance is remarkable, since iron (III) oxide films comprising only maghemite were found to exhibit a comparable intrinsic activity, but considerably lower stability for OER, while films of pure hematite were OER-inactive. These results are explained by the differences in the polymorph crystal structures, which cause different electrical conductivity and surface interactions with water molecules and protons. Our findings not only reveal the potential of iron (III) oxide as acid-stable OER catalyst, but also highlight the important yet hitherto largely unexplored effect of crystal polymorphism on electrocatalytic OER performance.
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| 6. |
- Kwong, Wai Ling, et al.
(författare)
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Scalable Two-Step Synthesis of Nickel Iron Phosphide Electrodes for Stable and Efficient Electrocatalytic Hydrogen Evolution
- 2017
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 121:1, s. 284-292
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Tidskriftsartikel (refereegranskat)abstract
- The development of efficient, durable, and inexpensive hydrogen evolution electrodes remains a key challenge for realizing a sustainable H-2 fuel production via electrocatalytic water splitting. Herein, nickel-iron phosphide porous films with precisely controlled metal content were synthesized on Ti foil using a simple and scalable two-step strategy of spray-pyrolysis deposition followed by low-temperature phosphidation. The nickel-iron phosphide of an optimized Ni:Fe ratio of 1:4 demonstrated excellent overall catalytic activity for hydrogen evolution reaction (HER) in 0.5 M H2SO4, achieving current densities of -10 and -30 mA cm(-2) at overpoteritials of 101 and 123 mV, respectively, with a Tafel slope of 43 mV dec(-1). Detailed analysis obtained by X-ray diffraction, electron microscopy, electrochemistry, and X-ray photoelectron spectroscopy revealed that the superior overall HER activity of nickel iron phosphide as compared to nickel phosphide and iron phosphide was a combined effect of differences in the morphology (real surface area) and the intrinsic catalytic properties (electronic structure). Together with a long-term stability and a near-100% Faradaic efficiency, the nickel-iron phosphide electrodes produced in this study provide blueprints for large-scale H-2 production.
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| 7. |
- Kwong, Wai Ling, et al.
(författare)
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Transparent Nanoparticulate FeOOH Improves the Performance of a WO3 Photoanode in a Tandem Water-Splitting Device
- 2016
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:20, s. 10941-10950
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen evolution catalysts (OEC) are often employed on the surface of photoactive, semiconducting photoanodes to boost their kinetics and stability during photoelectrochemical water oxidation. However, the necessity of using optically transparent OEC to avoid parasitic light absorption by the OEC under front-side illumination is often neglected. Here, we show that furnishing the surface of a WO3 photoanode with suitable loading of FeOOH as a transparent OEC improved the photocurrent density by 300% at 1 V versus RHE and the initial photocurrent-to-O-2 Faradaic efficiency from similar to 70 to similar to 100%. The data from the photo-voltammetry, electrochemical impedance, and gas evolution measurements these improvements were a combined result of reduced hole-transfer resistance for water oxidation, minimized surface recombination of charge carriers, and improved stability against photocorrosion of WO3. We demonstrate the utility of transparent FeOOH-coated W(O)3 in a solar-powered, tandem water-splitting device by combining it with a double-junction Si solar cell and a Ni-Mo hydrogen evolution catalyst. This device performed at a solar-to-hydrogen conversion efficiency of 1.8% in near-neutral K2SO4 electrolyte.
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