| 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. |
- Liu, Zhan, et al.
(författare)
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Thermodynamic analysis on the feasibility of a liquid energy storage system using CO2-based mixture as the working fluid
- 2022
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- Pioneering investigation is conducted on the feasibility of designing novel liquid energy storage system by using working fluid blending CO2 with organic fluids to address the condensation problem of subcritical CO2. Organic substances are cautiously screened according to the criteria of environment effect, temperature glide, critical temperature and flammability of working fluid as well as the system performance. Mathematical model of the system is built for thermodynamic examination. An in-house code is developed to complete the system simulations combing with REFPROP subroutine. Results demonstrate that compared to the system with pure CO2, the system with mixture produces an improvement of net power output and energy density and a reduction of charge pressure at an expense of slightly decreasing round trip efficiency. The payment of 6.45 % for round trip efficiency can reduce 55.59 % of charge pressure by taking CO2/R32 as an instance. The system round trip efficiency, energy density and charge pressure decrease with the increase in organic fluid composition. An optimal compression ratio can be identified to reach a maximal round trip efficiency for all mixtures. The cooler outlet temperature is suggested being at the critical temperature of working fluid to reach better system performance.
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| 3. |
- Pi, Xuehui, et al.
(författare)
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Mapping global lake dynamics reveals the emerging roles of small lakes
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Lakes are important natural resources and carbon gas emitters and are undergoing rapid changes worldwide in response to climate change and human activities. A detailed global characterization of lakes and their long-term dynamics does not exist, which is however crucial for evaluating the associated impacts on water availability and carbon emissions. Here, we map 3.4 million lakes on a global scale, including their explicit maximum extents and probability-weighted area changes over the past four decades. From the beginning period (1984–1999) to the end (2010–2019), the lake area increased across all six continents analyzed, with a net change of +46,278 km2, and 56% of the expansion was attributed to reservoirs. Interestingly, although small lakes (<1 km2) accounted for just 15% of the global lake area, they dominated the variability in total lake size in half of the global inland lake regions. The identified lake area increase over time led to higher lacustrine carbon emissions, mostly attributed to small lakes. Our findings illustrate the emerging roles of small lakes in regulating not only local inland water variability, but also the global trends of surface water extent and carbon emissions.
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