| 1. |
- Tang, Chengcheng, et al.
(författare)
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A case study on safety measures at median openings on four-lane trunk roads in China
- 2016
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Konferensbidrag (refereegranskat)abstract
- This paper describes the safety improvements that were made to an 11km long section of Class-I highway in Hexian county in the province of Anhui (chainage K45 to chainage K56) and summarizes the results of tests used to evaluate the likely changes in risk. Class-I highways mainly function as arterial highways with high design speeds (e.g. 80km/h, 100km/h) but have at-grade intersections and access points (that is, they are not accessed controlled). They typically have two lanes in each direction with a median. Following the occurrence of two deaths and four injuries on the road section during a four month period, conditions on the road were examined, including conducting a ChinaRAP assessment, and improvements were rapidly made. The improvements included speed management, adjustment of median openings, installation of protected turn lanes and delineation. In the 12 months after the improvements were made, no fatal or serious crashes occurred. Evaluations also show that there have been reductions in speed, improvements in the ChinaRAP risk scores and good acceptance of the changes by the local community.
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| 2. |
- Huijser, Annemarie, et al.
(författare)
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Shedding Light on the Nature of Photoinduced States Formed in a Hydrogen-Generating Supramolecular RuPt Photocatalyst by Ultrafast Spectroscopy
- 2018
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 122:31, s. 6396-6406
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Tidskriftsartikel (refereegranskat)abstract
- Photoinduced electronic and structural changes of a hydrogen-generating supramolecular RuPt photocatalyst are studied by a combination of time-resolved photoluminescence, optical transient absorption, and X-ray absorption spectroscopy. This work uses the element specificity of X-ray techniques to focus on the interplay between the photophysical and -chemical processes and the associated time scales at the catalytic Pt moiety. We observe very fast (<30 ps) photoreduction of the Pt catalytic site, followed by an ∼600 ps step into a strongly oxidized Pt center. The latter process is likely induced by oxidative addition of reactive iodine species. The oxidized Pt species is long-lived and fully recovers to the original ground state complex on a >10 μs time scale. However, the photosensitizing Ru moiety is fully restored on a much shorter ∼300 ns time scale. This reaction scheme implies that we may withdraw two electrons from a catalyst that is activated by a single photon.
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| 3. |
- Liu, Cunming, et al.
(författare)
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Asynchronous Photoexcited Electronic and Structural Relaxation in Lead-Free Perovskites
- 2019
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 141:33, s. 13074-13080
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Tidskriftsartikel (refereegranskat)abstract
- Vacancy-ordered lead-free perovskites with more-stable crystalline structures have been intensively explored as the alternatives for resolving the toxic and long-term stability issues of lead halide perovskites (LHPs). The dispersive energy bands produced by the closely packed halide octahedral sublattice in these perovskites are meanwhile anticipated to facility the mobility of charge carriers. However, these perovskites suffer from unexpectedly poor charge carrier transport. To tackle this issue, we have employed the ultrafast, elemental-specific X-ray transient absorption (XTA) spectroscopy to directly probe the photoexcited electronic and structural dynamics of a prototypical vacancy-ordered lead-free perovskite (Cs3Bi2Br9). We have discovered that the photogenerated holes quickly self-trapped at Br centers, simultaneously distorting the local lattice structure, likely forming small polarons in the configuration of Vk center (Br2 - dimer). More significantly, we have found a surprisingly long-lived, structural distorted state with a lifetime of ∼59 μs, which is ∼3 orders of magnitude slower than that of the charge carrier recombination. Such long-lived structural distortion may produce a transient "background" under continuous light illumination, influencing the charge carrier transport along the lattice framework. ©
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| 4. |
- Shao, Jingxia, et al.
(författare)
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Functional analysis of the HD-Zip transcription factor genes Oshox12 and Oshox14 in rice
- 2018
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- The homeodomain-leucine zipper (HD-Zip) transcription factor family plays vital roles in plant development and morphogenesis as well as responses to biotic and abiotic stresses. In barley, a recessive mutation in Vrs1 (HvHox1) changes two-rowed barley to six-rowed barley, which improves yield considerably. The Vrs1 gene encodes an HD-Zip subfamily I transcription factor. Phylogenetic analysis has shown that the rice HD-Zip I genes Oshox12 and Oshox14 are the closest homologues of Vrs1. Here, we show that Oshox12 and Oshox14 are ubiquitously expressed with higher levels in developing panicles. Trans-activation assays in yeast and rice protoplasts demonstrated that Oshox12 and Oshox14 can bind to a specific DNA sequence, AH1 (CAAT(A/T)ATTG), and activate reporter gene expression. Overexpression of Oshox12 and Oshox14 in rice resulted in reduced panicle length and a dwarf phenotype. In addition, Oshox14 overexpression lines showed a deficiency in panicle exsertion. Our findings suggest that Oshox12 and Oshox14 may be involved in the regulation of panicle development. This study provides a significant advancement in understanding the functions of HD-Zip transcription factors in rice.
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| 5. |
- Yang, Xianyan, et al.
(författare)
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Intra-bone marrow injection of trace elements co-doped calcium phosphate microparticles for the treatment of osteoporotic rat
- 2017
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Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 105:5, s. 1422-1432
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Tidskriftsartikel (refereegranskat)abstract
- Osteoporotic femur fractures are the most common fragility fracture and account for approximately one million injuries per year. Local intervention by intra-marrow injection is potentially a good choice for preventing osteoporotic bone loss when the osteoporotic femoral fracture was treated. Previously, it was shown that trace element co-doped calcium phosphate (teCaP) implants could stimulate osteoporotic bone marrow mesenchymal stem cell activity in vitro and bone regeneration in femoral bone defects in osteoporotic animal models. They hypothesized that local intra-marrow injection of teCaP particles could improve bone function because the teCaP can sustain release of biologically essential inorganic minerals and improve bone remodeling in osteoporosis. The teCaP and CaP particles were synthesized in simulated body fluid with and without adding silicon, zinc and strontium ions. Female rats (8 months) were ovariectomized (OVX) or sham-operated, and then intervened in the femoral marrow space at 12 months old. Groups include: (1) saline water; (2) CaP particles; and (3) teCaP particles. After 2-3 months of intervention, the sham groups showed higher bone mineral density (MBD) in the femur, and teCaP group increased the BMD in the OVX groups. The compressive strength of the OVX-teCaP group was significantly higher than that in the OVX-CaP group. Significant differences between OVX-teCaP and OVX-CaP groups were found for bone mineral microarchitecture, bone mineral density, and trace mineral content, but not for feces composition. These results confirm the teCaP particles could suppress osteoporotic bone loss by local intramarrow injection. Therefore, this biomaterial could be used as a next-generation combination treatment for osteoporotic trauma and osteoporosis itself.
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| 6. |
- Zhang, Qian, 1977-, et al.
(författare)
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Internal and international migration dynamics in China
- 2018
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Ingår i: Handbook of Migration and Globalisation. - Cheltenham : Edward Elgar Publishing. - 9781785367502 - 9781785367519 ; , s. 297-317
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Zheng, Kaibo, et al.
(författare)
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Direct Experimental Evidence for Photoinduced Strong-Coupling Polarons in Organolead Halide Perovskite Nanoparticles
- 2016
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 7:22, s. 4535-4539
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Tidskriftsartikel (refereegranskat)abstract
- Echoing the roaring success of their bulk counterparts, nano-objects built from organolead halide perovskites (OLHP) present bright prospects for surpassing the performances of their conventional organic and inorganic analogues in photodriven technologies. Unraveling the photoinduced charge dynamics is essential for optimizing the optoelectronic functionalities. However, mapping the carrier-lattice interactions remains challenging, owing to their manifestations on multiple length scales and time scales. By correlating ultrafast time-resolved optical and X-ray absorption measurements, this work reveals the photoinduced formation of strong-coupling polarons in CH3NH3PbBr3 nanoparticles. Such polarons originate from the self-trapping of electrons in the Coulombic field caused by the displaced inorganic nuclei and the oriented organic cations. The transient structural change detected at the Pb L3 X-ray absorption edge is well-captured by a distortion with average bond elongation in the [PbBr6]2- motif. General implications for designing novel OLHP nanomaterials targeting the active utilization of these quasi-particles are outlined.
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