| 1. |
- Hu, Jinghua, et al.
(författare)
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Synthesis and First-principle Calculation of TiO2 Rutile Nanowire Electrodes for Dye-sensitized Solar Cells
- 2017
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Ingår i: International Journal of Electrochemical Science. - : Electrochemical Science Group. - 1452-3981. ; 12:10, s. 9725-9735
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a TiO2 nanowire film synthesized via a hydrothermal method was prepared as a photoanode for dye-sensitized solar cells (DSSCs). The synthesized TiO2 nanowires were characterized by transmission electron microscopy and X-ray diffraction. The TiO2 nanowire film greatly improved the efficiency of the DSSC owing to the rapid interfacial electron transport in the one-dimensional TiO2 nanowires. The light absorption and interfacial electron transport, which play important roles in the efficiency of DSSCs, were investigated by UV-vis absorption spectroscopy and electrochemical impedance spectroscopy. The energy band structure and electron density of states of the rutile nanowire were calculated using a first-principles method and compared to bulk anatase and rutile TiO2 phases. The band gap of the rutile TiO2 nanowire was found to be less than that of anatase TiO2 by 0.6 eV. Further calculations using GGA+U yielded a similar band gap reduction. In addition to the redshift of the absorption edge originating from the smaller band gap, the larger surface area of the TiO2 nanowire compared to the bulk material is expected to facilitate the migration of photogenerated electrons and holes from inside to the surface of the material. This would result in a considerable improvement of the photocatalytic efficiency of TiO2.
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| 2. |
- Kilpeläinen, Tuomas O, et al.
(författare)
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Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.
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| 3. |
- Zhang, Hui, et al.
(författare)
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Comprehensive electronic structure characterization of pristine and nitrogen/phosphorus doped carbon nanocages
- 2016
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Ingår i: Carbon. - : Elsevier. - 0008-6223 .- 1873-3891. ; 103, s. 480-487
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structures of carbon nanocages (CNCs) and nitrogen/phosphorus doped carbon nanocages (N-CNCs/P-CNCs) have been studied by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and resonant X-ray emission spectroscopy (RXES). The doping configurations for N/P dopants are identified from the experiments. The results have shown that there are three major doping configurations for nitrogen but only one doping configuration for phosphorus. The nitrogen doping reveals the complex coexistence of graphite-like, pyridine-like and pyrrole-like configurations that are proved by density functional theory (DFT) simulations, while the phosphorus doping presents only the "graphite-like" configuration. The different configuration profiles result in less atomic structure ordering of N-CNCs than that of P-CNCs. XAS spectra obtained from both surface and bulk sensitive detection suggest different chemical environments between the interior and shell for all types of nanocages. The electronic structure modifications show significant difference between nitrogen and phosphorus doping from the DOS calculations. (C) 2016 Elsevier Ltd. All rights reserved.
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