| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)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. |
- Wang, Mengmeng, et al.
(author)
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Statistical analysis of whistler precursors upstream of foreshock transient shocks : MMS observations
- 2024
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In: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 51:8
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Journal article (peer-reviewed)abstract
- Using the high-time-resolution data from the Magnetospheric Multiscale mission, precursor waves upstream of foreshock transient (FT) shocks are statistically investigated using the four-spacecraft timing method. The wave frequencies and wave vectors determined in the plasma rest frame (PRF) are shown to follow the cold plasma dispersion relation for whistler waves. Combining with the feature of the right-hand polarization in the PRF, the precursors are identified as whistler-mode waves around the lower hybrid frequency. The occurrence of whistler precursors is independent of the Alfvén Mach number and the FT shock normal angle. More importantly, all the whistler precursors have group velocities pointing upstream in the shock frame, suggesting the dispersive radiation to be a possible generation mechanism. The study improves the understanding of not only the whistler precursors but also the overall FT shock dynamics.
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| 3. |
- Wang, Yuqi, et al.
(author)
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Electrolyte-Mediated Misconception of Carbon-Based Electrode Performance and Beyond in Metal-Ion Batteries
- 2023
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In: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 13:29
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Journal article (peer-reviewed)abstract
- A half-cell that is composed of electrode and metal (e.g., lithium) is the most classical model for examining electrode performance in battery community, by which the voltage versus capacity profile is the important indicator. However, it is found that these results are not all reliable, as a misconception of electrode performance can be caused once the electrolyte is chemically unstable. As a paradigm, it is demonstrated that the diethyl carbonate (DEC) solvent can chemically react with lithium metal to form insoluble and soluble by-products, which can accumulate on the lithium anode to influence the lithium potential and/or migrate to the counter electrode to proceed with the uncompleted electrochemical reactions. The resultant voltage-capacity profile cannot reflect the actual electrode performance, such as the lithium storing capability within the graphite. The reason for this phenomenon is elucidated based on solvation chemistry, particularly the mechanism of mitigating it by introducing ethylene carbonatesolvent to form new hydrogen bonds. The viewpoint is further verified by employing the full cell and also extended in sodium and potassium batteries. This study shows the necessity of discerning the reliability of electrode performance and also sheds light on the importance of designing a compatible electrolyte to examine electrode performance.
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