| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- 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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| 3. |
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| 4. |
- Li, Yuyang, et al.
(författare)
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A General Carboxylate-Assisted Approach to Boost the ORR Performance of ZIF-Derived Fe/N/C Catalysts for Proton Exchange Membrane Fuel Cells
- 2021
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- An Fe/N/C catalyst derived from the pyrolysis of metal-organic frameworks, for example, a zeolitic-imidazolate-framework-8 (ZIF-8), has been regarded as one of the most promising non-precious metal catalysts toward oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, its ORR mass activity is still much inferior to that of Pt, partly because of the lack of general and efficient synthetic strategies. Herein, a general carboxylate-assisted strategy that dramatically enhances the ORR mass activity of ZIF-derived Fe/N/C catalysts is reported. The carboxylate is found to promote the formation of Fe/N/C catalysts with denser accessible active sites and entangled carbon nanotubes, as well as a higher mesoporosity. These structural advantages make the carboxylate-assisted Fe/N/C catalysts show a 2-10 fold higher ORR mass activity than the common carboxylate-free one in various cases. When applied in H-2-O-2 PEMFCs, the active acetate-assisted Fe/N/C catalyst generates a peak power density of 1.33 W cm(-2), a new record of peak power density for a H-2-O-2 PEMFC with non-Pt ORR catalysts.
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| 5. |
- Kohse-Höinghaus, Katharina, et al.
(författare)
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Chemistry diagnostics for monitoring
- 2023
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Ingår i: Combustion Chemistry and the Carbon Neutral Future : What will the Next 25 Years of Research Require? - What will the Next 25 Years of Research Require?. - 9780323992138 ; , s. 417-501
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Bokkapitel (refereegranskat)abstract
- Chemically sensitive diagnostics are indispensable to unravel reactive processes in combustion and beyond, to understand their development in time and space and to monitor the reaction progress under the conditions of interest. A multitude of techniques is available that may provide species composition together with other process-controlling variables as a function of the reaction environment. Analytical tools have been developed that range from one-of-a-kind large-facility instrumentation to robust sensors for use in technical systems and in the field. In this chapter, needs and developments for the near and midterm future are addressed combining individual contributions from selected perspectives and intertwining thoughts and ideas from different fields and expertise. Major advances can be expected from combinations of instrumentation and digital processes, with beneficial uses for a multitude of processes in carbon-reduced and carbon-neutral environments.
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| 6. |
- Wei, Lai, et al.
(författare)
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Multiscale identification of urban functional polycentricity for planning implications : An integrated approach using geo-big transport data and complex network modeling
- 2020
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Ingår i: Habitat International. - : Elsevier BV. - 0197-3975. ; 97
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Tidskriftsartikel (refereegranskat)abstract
- Polycentrism has gradually become a newly emergent dimension of global urbanization. Many countries worldwide have tailored plans suited to functional polycentricity, in light of the prevalent “ghost cities” or “empty towns” as lessons from the morphologically polycentric development practices. However, the subject of defining and measuring functional polycentricity is still in an initial development phase, both in theory and in methodology. This paper first establishes a general theoretical framework for understanding functional polycentricity from the lens of interactive human mobility among spatial units. Then, a new approach is proposed to identify and measure urban functional polycentricity from a multiscale perspective and further applied to the case of Shanghai, China. More specifically, the pick-up and drop-off points from taxi GPS data are used to examine the linkages among different urban units across various scales (e.g., census tract, 3000-m grid, 5000-m grid, and community). Complex network modeling, together with the sensitivity analysis, is further employed to identify the centers according to the spatial importance of each unit. The results show that (1) the approach proposed can effectively identify functional centers within urban setting; (2) an obvious polycentric structure exists in Shanghai and is sensitive to scale effects; (3) the estimates are more accurate and precise with the shrink of analysis unit size from community level to census tract level; and (4) under the same spatial scale, the grid-based analysis produces a more elaborated polycentric pattern compared with the traditional administration-based analysis. Finally, scale-dependent differences between morphological and functional polycentricity are distinguished for providing implications for urban planning. Our study is believed to renew the knowledge of polycentricity conceptualization.
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