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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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| 2. |
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| 3. |
- Flores-Diaz, Natalie, et al.
(författare)
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Neutral organic redox pairs based on sterically hindered hydroquinone/benzoquinone derivatives for dye-sensitized solar cells
- 2018
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 167, s. 76-83
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Tidskriftsartikel (refereegranskat)abstract
- Substituted derivatives of hydroquinone/benzoquinone were studied as organic redox mediators in the electrolyte for dye-sensitized solar cells (DSSCs). Thus, di-tert-butylhydroquinone (DTHQ), thymohydroquinone (ThymHQ) and phenylhydroquinone (PhHQ), were combined with their oxidized counterparts to form the pairs DTHQ/DTBQ, ThymHQ/ThymBQ, and PhHQ/PhBQ. In general, the characteristic parameters of the DSSCs with the substituted derivatives surpassed those of the DSSC with the unsubstituted hydroquinone/benzoquinone electrolyte. The short-circuit current (J(sc)) of the devices using DTHQ/DTBQ and ThymHQ/ThymBQ (13.61 mA cm(-2) and 12.56 mA cm(-2), respectively) are comparable to the J(sc) obtained for cobalt(II/III) tris (bipyridine) as a reference electrolyte (14.54 mA cm(-2)). However, parameters such as open-circuit voltage (V-oc) and fill factor (FF) (547 mV and 0.48, respectively) are far from competitive. The best photovoltaic performance was obtained for the pair ThymHQ/ThymBQ using a triphenylamine (TPA)-based organic dye (LEG4) as sensitizer and a hybrid counter electrode with poly(3,4-ethylenedioxythiophene) (PEDOT) and graphene. These experimental conditions give under 1 sun (98%) the highest efficiency (eta = 3.19%); low-light intensities of 12.3% and 51.8% suns lead to efficiencies of 3.34% and 3.29%, respectively. Electrochemical impedance spectroscopy (EIS) revealed that the main cause for loss in photocurrent is the low recombination resistance compared to Co(II/III) as reference electrolyte. Based on the EIS analysis, a down-shift of the conduction band of TiO2 was found for all assembled devices containing the organic redox mediators, which explains the low V-oc values for these derivatives.
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| 4. |
- Pecunia, Vincenzo, et al.
(författare)
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Roadmap on energy harvesting materials
- 2023
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Ingår i: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.
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