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- 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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| 4. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 5. |
- Zhao, Shijing, et al.
(författare)
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Elucidating the reaction pathway of crystalline multi-metal borides for highly efficient oxygen-evolving electrocatalysts
- 2022
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 10:3, s. 1569-1578
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the fundamental principle of catalytic performance and the mechanism of multimetal-based electrocatalysts is essential for the rational design of advanced renewable energy systems. Here, highly crystalline MMMoB4 (M = Fe, Co) compounds with controllable compositions of multiple active metal atoms and polyacene-type boron networks were synthesized delicately by a one-step high-pressure technique to explore electrocatalytic selectivity and activity. CoFeMoB4 and Co2MoB4 are revealed to be highly active and durable oxygen evolution reaction (OER) electrocatalysts under alkaline conditions. The mutually promotive activation of metals with amorphous clusters and ultra-small grains on the surface are responsible for the enhanced activity of CoFeMoB4. More specifically, Co and Fe coupling in CoFeMoB4 facilitates surface reconstruction into active Co hydroxide and Fe oxyhydroxide, in contrast to Co oxyhydroxide in Co2MoB4 and Fe oxides in Fe2MoB4. Dissolving Mo may provide potential space for adsorbing hydroxyl, and the optimized electronic structure with boron is mainly responsible for the long-term durability. In contrast, Mo atoms are responsible for hydrogen evolution reaction (HER) properties, and the optimized d-band center and density of states at the Fermi level make Co2MoB4 a superior HER catalyst. Our findings provide insight into distinguishing the catalytic pathway of multi-metal borides with improved OER activity and different roles of Mo and Co/Fe in the HER and OER.
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| 9. |
- Cheng, Hao-Wen, et al.
(författare)
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Realizing Efficient Charge/Energy Transfer and Charge Extraction in Fullerene-Free Organic Photovoltaics via a Versatile Third Component
- 2019
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Ingår i: Nano letters (Print). - : AMER CHEMICAL SOC. - 1530-6984 .- 1530-6992. ; 19:8, s. 5053-5061
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Tidskriftsartikel (refereegranskat)abstract
- Solution-processed organic photovoltaics (OPVs) based on bulk-heterojunctions have gained significant attention to alleviate the increasing demend of fossil fuel in the past two decades. OPVs combined of a wide bandgap polymer donor and a narrow bandgap nonfullerene acceptor show potential to achieve high performance. However, there are still two reasons to limit the OPVs performance. One, although this combination can expand from the ultraviolet to the near-infrared region, the overall external quantum efficiency of the device suffers low values. The other one is the low open-circuit voltage (V-OC) of devices resulting from the relatively downshifted lowest unoccupied molecular orbital (LUMO) of the narrow bandgap. Herein, the approach to select and incorporate a versatile third component into the active layer is reported. A third component with a bandgap larger than that of the acceptor, and absorption spectra and LUMO levels lying within that of the donor and acceptor, is demonstrated to be effective to conquer these issues. As a result, the power conversion efficiencies (PCEs) are enhanced by the elevated short-circuit current and V-OC; the champion PCEs are 11.1% and 13.1% for PTB7-Th:IEICO-4F based and PBDB-T:Y1 based solar cells, respectively.
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| 10. |
- Cui, Song, et al.
(författare)
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Understanding the risks from diffuse pollution on wetland eco-systems : The effectiveness of water quality classification schemes
- 2020
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 155
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Tidskriftsartikel (refereegranskat)abstract
- Eco-environmental safety and health is an important concept for the protection of flora and fauna in the wetland eco-system. Identifying impacts of human activities on wetland ecology and risk factors of environmental decline have become significant components of habitat protection. In this study, the Qixing River wetland, one of the Ramsar Sites, was taken as the research area. Seven water quality indices, including dissolved oxygen (DO), chemical oxygen demand (COD), ammonia nitrogen (NH3 - N), total phosphorus (TP), total nitrogen (TN), nitrates and nitrites were monitored at fifteen sampling locations. Entropy weight-set pair analysis, combined with discriminant analysis, was used to identify the most sensitive indicators for changes in water quality. Average concentrations for the indicators measured were: DO 7.24 (4.64-9.98) mg/L; COD 21.67 (5-50) mg/L; NH3-N 1.09 (0.41-2.15) mg/L; TP 0.18 (0.10-0.73) mg/L; TN 1.38 (0.76-2.17) mg/L, nitrite 0.016 (ND - 0.030) mg/L and nitrate concentration was 0.420 (0.315-0.613) mg/L. Water quality was found to be poorest at locations closer to sources of diffuse pollution such as agricultural land. In contrast, the more remote buffer zone and core zone of the wetland was characterized by improved indicators of water quality. The results of entropy weight-set pair analysis showed that the overall water quality grade of Qixing River wetland conforms to Class III of the "Environmental Quality Standards for Surface Water" of China (GB3838-2002). Discriminant analysis indicated that TP was the main contributory factor to reduced water quality classification while COD, ammonia nitrogen and total nitrogen were the key drivers of improving water quality grade and responsible for the Class III award. The prominence of these indicators is indicative of long-term use of fertilizers and pesticides in agricultural production. The more remote core area of the wetland was less affected by human activities, reflected in improved water quality results. The results showed that entropy weight-set pair analysis coupled with discriminant analysis adds value to widely used water environment quality indices and helps identify the main environmental factors driving water quality classification. In the case of the Qixing River wetland, there is clear potential to protect wetland eco-system safety by improving the water quality classification and reforming agronomic and land management practices.
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