| 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. |
- Wang, Weichao, et al.
(författare)
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Remarkably enhanced hybrid piezo/triboelectric nanogenerator via rational modulation of piezoelectric and dielectric properties for self-powered electronics
- 2020
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 116:2
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Tidskriftsartikel (refereegranskat)abstract
- The hybridization of different materials for energy scavenging techniques based on piezoelectric and triboelectric effects has been studied widely for various applications of nanogenerators. However, there are few reports utilizing the same oxide matrix materials with appropriate doping to simultaneously enhance the piezoelectric and triboelectric outputs. Herein, a hybrid nanogenerator (HG) consisting of a piezoelectric nanogenerator (PENG) and a triboelectric nanogenerator (TENG) was constructed using (Ba0.838Ca0.162)(Ti0.9072Zr0.092)O3 (BCZTO)/polydimethylsiloxane (PDMS) as a piezoelectric layer and Ba(Ti0.8Zr0.2)O3 (BZTO)/PDMS as a triboelectric layer. For the PENG, how the electrical output was related to the BCZTO ratio in the BCZTO/PDMS composite films was systematically investigated. For the TENG, remarkably enhanced output performance is attributed to the ferroelectric polarization and large permittivity of the BZTO/PDMS. The Kelvin probe force microscopy measurements show that the poled BZTO/PDMS composite film with a 20 wt. % mass ratio of BZTO has the highest surface charge potential, in line with the macroscopic electrical outputs of the TENG. Interestingly, the output performance of the PENG in the HG is significantly enhanced compared to the PENG acting alone, which is also verified by COMSOL simulation. After rectification, the HG can produce a maximum output voltage of 390 V and a current density of 47 mA/m2. This work not only provides a feasible solution to enhance the output performance of the HG but also offers an effective approach to develop a small, portable power source with promising application in self-powered electronics.
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