| 1. |
- Botvinik-Nezer, Rotem, et al.
(författare)
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Variability in the analysis of a single neuroimaging dataset by many teams
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 582, s. 84-88
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Tidskriftsartikel (refereegranskat)abstract
- Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses(1). The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset(2-5). Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed. The results obtained by seventy different teams analysing the same functional magnetic resonance imaging dataset show substantial variation, highlighting the influence of analytical choices and the importance of sharing workflows publicly and performing multiple analyses.
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| 2. |
- Cheng, Shi-Ping, et al.
(författare)
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Haplotype-resolved genome assembly and allele-specific gene expression in cultivated ginger
- 2021
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Ingår i: Horticulture Research. - : Springer Nature. - 2052-7276. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Ginger (Zingiber officinale) is one of the most valued spice plants worldwide; it is prized for its culinary and folk medicinal applications and is therefore of high economic and cultural importance. Here, we present a haplotype-resolved, chromosome-scale assembly for diploid ginger anchored to 11 pseudochromosome pairs with a total length of 3.1 Gb. Remarkable structural variation was identified between haplotypes, and two inversions larger than 15 Mb on chromosome 4 may be associated with ginger infertility. We performed a comprehensive, spatiotemporal, genome-wide analysis of allelic expression patterns, revealing that most alleles are coordinately expressed. The alleles that exhibited the largest differences in expression showed closer proximity to transposable elements, greater coding sequence divergence, more relaxed selection pressure, and more transcription factor binding site differences. We also predicted the transcription factors potentially regulating 6-gingerol biosynthesis. Our allele-aware assembly provides a powerful platform for future functional genomics, molecular breeding, and genome editing in ginger.
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| 3. |
- Du, Wanyi, et al.
(författare)
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Photodoping of graphene/silicon van der Waals heterostructure observed by terahertz emission spectroscopy
- 2020
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 117:8
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Tidskriftsartikel (refereegranskat)abstract
- Photodoping as a nonvolatile and reversible method can be used to modify the carrier distribution at the heterojunction interface. Herein, we explore the 2D/3D van der Waals (vdW) graphene/silicon (G/Si) heterostructure in real time by terahertz (THz) emission spectroscopy. Photoinduced doping is introduced by a continuous wave laser, which leads to a screening effect to the built-in electric field at the interface. The resulting decrease in transient photocurrent reduces the THz emission amplitude from the G/Si heterostructure. The photoinduced doping effect suggests a 40% THz intrinsic modulation depth at external reverse bias. This work provides an effective way to actively control the THz emission process from the G/Si interface and paves the way for analyzing the interfacial process under photoinduced doping in vdW heterostructures.
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| 4. |
- Fang, Xing, et al.
(författare)
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Microstructure and mechanical properties of the laser welded air-hardening steel joint
- 2024
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Ingår i: Materials Characterization. - : Elsevier BV. - 1044-5803 .- 1873-4189. ; 213
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Tidskriftsartikel (refereegranskat)abstract
- The decrease in mechanical properties of high-strength steel after welding is an important issue affecting the wide application of high-strength steel. Air-hardening steel is a high-strength steel suitable for lower body structural parts such as subframes. Its application process involves welding, hot forming and other processes. The present work investigates the microstructure and mechanical properties of the air-hardening steel laser welded joint that is air-cooled after hot forming in the two-phase zone (800 °C). The microstructure was characterized by electron backscattered diffraction (EBSD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that during hot forming, the welded joint transforms from martensite to ferrite and acicular martensite, and the base metal transforms from ferrite to polygonal martensite and ferrite. The difference in martensite morphology between the welded joint and the base metal is attributed to the nucleation positions of austenite. The structural evolution of the welded joint and the base metal is accompanied with the annihilation and reproduction of dislocations, which results in significant changes in hardness. The hardness value dropped from the highest 430 HV to 271 HV in the welded joint, while increased from the lowest 184 HV to 203 HV in the base metal. After hot forming, the tensile strength of the welded sample is reduced by only 36 MPa, and the total elongation is slightly decreased by about 1.5% compared with the unwelded sample. The welded joint and the base metal have similar plastic deformation capabilities, since the acicular martensite in the welded joint displays good plastic deformation ability, and the dislocation density of the welded joint and the base metal is similar. Overall, the microstructure and dislocation density of the air-hardening steel welded joint after hot forming are similar to those of the base metal, which is responsible for the good mechanical properties of air-hardening steel welded joint.
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| 5. |
- Ingason, Haukur, et al.
(författare)
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Fire tests with automatic sprinklers in an intermediate scale tunnel
- 2022
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Ingår i: Fire safety journal. - : Elsevier Ltd. - 0379-7112 .- 1873-7226. ; 129
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Tidskriftsartikel (refereegranskat)abstract
- A series of 1:3 intermediate scale tunnel fire tests was performed to investigate the performance of a fully automatic sprinkler system in a road tunnel. The experiments were carried in a container tunnel with scaled geometry, using wood pallets as the fire source to simulate HGV fires. The activation of the sprinklers was simulated by using thermocouples that corresponded to a given Thermal Response Index (RTI) of a sprinkler bulb or a link. A total of 12 tests were carried out with varying longitudinal velocities (0.8–1.7 m/s), sprinkler activation temperatures (68–141 °C), water densities (2.9–8.7 mm/min) and types of arrangement of the fuel. The activation times, number of activated sprinklers, maximum heat release rates and other key parameters are presented and analyzed. The results show that the water density plays a key role in the performance of the automatic sprinkler systems tested. A high tunnel ventilation velocity, low water density and low sprinkler activation temperature are not recommended. © 2022 The Authors
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| 6. |
- Li, You, et al.
(författare)
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Preinvasion Assessment of Exotic Bark Beetle-Vectored Fungi to Detect Tree-Killing Pathogens
- 2022
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Ingår i: Phytopathology. - 0031-949X. ; 112:2, s. 261-270
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Tidskriftsartikel (refereegranskat)abstract
- Exotic diseases and pests of trees have caused continental-scale disturbances in forest ecosystems and industries, and their invasions are considered largely unpredictable. We tested the concept of preinvasion assessment of not yet invasive organisms, which enables empirical risk assessment of potential invasion and impact. Our example assesses fungi associated with Old World bark and ambrosia beetles and their potential to impact North American trees. We selected 55 Asian and European scolytine beetle species using host use, economic, and regulatory criteria. We isolated 111 of their most consistent fungal associates and tested their effect on four important southeastern American pine and oak species. Our test dataset found no highly virulent pathogens that should be classified as an imminent threat. Twenty-two fungal species were minor pathogens, which may require context-dependent response for their vectors at North American borders, while most of the tested fungi displayed no significant impact. Our results are significant in three ways; they ease the concerns over multiple overseas fungus vectors suspected of heightened potential risk, they provide a basis for the focus on the prevention of introduction and establishment of species that may be of consequence, and they demonstrate that preinvasion assessment, if scaled up, can support practical risk assessment of exotic pathogens.
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| 7. |
- Li, Zhen, et al.
(författare)
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Photocatalytic Hydrogen Production
- 2022
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Ingår i: Photo‐ and Electro‐Catalytic Processes. - : John Wiley & Sons. ; , s. 415-483
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Xu, Lei, et al.
(författare)
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The Role of Solution Aggregation Property toward High-Efficiency Non-Fullerene Organic Photovoltaic Cells
- 2024
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- In organic photovoltaic cells, the solution-aggregation effect (SAE) is long considered a critical factor in achieving high power-conversion efficiencies for polymer donor (PD)/non-fullerene acceptor (NFA) blend systems. However, the underlying mechanism has yet to be fully understood. Herein, based on an extensive study of blends consisting of the representative 2D-benzodithiophene-based PDs and acceptor-donor-acceptor-type NFAs, it is demonstrated that SAE shows a strong correlation with the aggregation kinetics during solidification, and the aggregation competition between PD and NFA determines the phase separation of blend film and thus the photovoltaic performance. PDs with strong SAEs enable earlier aggregation evolutions than NFAs, resulting in well-known polymer-templated fibrillar network structures and superior PCEs. With the weakening of PDs' aggregation effects, NFAs, showing stronger tendencies to aggregate, tend to form oversized domains, leading to significantly reduced external quantum efficiencies and fill factors. These trends reveal the importance of matching SAE between PD and NFA. The aggregation abilities of various materials are further evaluated and the aggregation ability/photovoltaic parameter diagrams of 64 PD/NFA combinations are provided. This work proposes a guiding criteria and facile approach to match efficient PD/NFA systems. A systematic study of the representative organic photovoltaic systems shows that the aggregation competition between polymer donor (PD) and non-fullerene acceptor (NFA) is a decisive factor in the phase separation of blend film and thus the photovoltaic performance. Based on 64 PD/NFA combinations, the aggregation ability/photovoltaic parameter heatmaps are plotted, providing a new matching rule for developing high-efficiency PD/NFA systems. image
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| 9. |
- Yao, Zehan, et al.
(författare)
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Magnetization-induced optical rectification and inverse spin Hall effect for interfacial terahertz generation in metallic heterostructures
- 2021
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Ingår i: Physical Review B. - 2469-9950. ; 103:20
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Tidskriftsartikel (refereegranskat)abstract
- Metallic heterostructure as promising terahertz (THz) spintronic emitters has promoted the development of both spintronics and THz science. However, the underlying physics at the metallic interface, such as the nonlinear optical effect, remains unclear. Herein, we present interface magnetization induced THz generation from metallic heterostructure consisting of Heusler alloy CoFeMnSi (CFMS) and Pd thin films. THz generation is ascribed to 35% contribution from the magnetization-induced optical rectification (MOR) and 65% contribution from inverse spin Hall effect (ISHE) based on the pump polarization and sample azimuthal angle dependent measurement. Furthermore, the contribution ratio of the MOR decreases to 12% via lowering the CFMS grown temperature, which is due to the reduced crystalline quality and possible metal to semiconductor transformation in CFMS. Our results not only clarify MOR and ISHE in metallic heterostructure for the scientific field, but they also benefit THz source optimization for the technology field.
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| 10. |
- Yin, Xiu, et al.
(författare)
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Doping of charge-transfer molecules in cocrystals for the design of materials with novel piezo-activated luminescence
- 2023
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Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 14:6, s. 1479-1484
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Tidskriftsartikel (refereegranskat)abstract
- A novel piezo-activated luminescent material with wide range modulation of the luminescence wavelength and a giant intensity enhancement upon compression was prepared using a strategy of molecular doping. The doping of THT molecules into TCNB-perylene cocrystals results in the formation of a weak but pressure-enhanced emission center in the material at ambient pressure. Upon compression, the emissive band from the undoped component TCNB-perylene undergoes a normal red shift and emission quenching, while the weak emission center shows an anomalous blue shift from 615 nm to 574 nm and a giant luminescence enhancement up to 16 GPa. Further theoretical calculations show that doping by THT could modify intermolecular interactions, promote molecular deformation, and importantly, inject electrons into the host TCNB-perylene upon compression, which contributes to the novel piezochromic luminescence behavior. Based on this finding, we further propose a universal approach to design and regulate the piezo-activated luminescence of materials by using other similar dopants.
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