| 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. |
- Huang, Shih-Wen, et al.
(author)
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Prominent role of oxygen in the multiferroicity of DyMnO3 and TbMnO3: A resonant soft x-ray scattering spectroscopy study
- 2016
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In: Physical Review B (Condensed Matter and Materials Physics). - 2469-9950. ; 94:3
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Journal article (peer-reviewed)abstract
- Oxygen is known to play an important role in the multiferroicity of rare earth manganites; however, how this role changes with rare earth elements is still not fully understood. To address this question, we have used resonant soft x-ray scattering spectroscopy to study the F-type (0,τ,0) diffraction peak from the antiferromagnetic order in DyMnO3 and TbMnO3. We focus on the measurements at O K edge of these two manganites, supplemented by the results at Mn L2 and Dy M5 edge of DyMnO3. We show that the electronic states of different elements are coupled more strongly in DyMnO3 than in TbMnO3, presumably due to the stronger lattice distortion and the tendency to develop E-type antiferromagnetism in the ferroelectric state that promote the orbital hybridization. We also show that the anomaly in the correlation length of (0,τ,0) peak in DyMnO3 signifies the exchange interaction between Mn and rare earth spins. Our findings reveal the prominent role of oxygen orbitals in the multiferroicity of rare earth manganites and the distinct energetics between them.
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| 3. |
- Wang, Tongzhou, et al.
(author)
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Atomically Dispersed Semi-Metallic Selenium on Porous Carbon Membrane as an Electrode for Hydrazine Fuel Cells
- 2019
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In: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 58:38, s. 13466-13471
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Journal article (peer-reviewed)abstract
- Electrochemically functional porous membranes of low cost are appealing in various electrochemical devices used in modern environmental and energy technologies. Herein we describe a scalable strategy to construct electrochemically active, hierarchically porous carbon membranes containing atomically dispersed semi-metallic Se, denoted SeNCM. The isolated Se atoms were stabilized by carbon atoms in the form of a hexatomic ring structure, in which the Se atoms were located at the edges of graphitic domains in SeNCM. This configuration is different from that of previously reported transition/noble metal single atom catalysts. The positively charged Se, enlarged graphitic layers, robust electrochemical nature of SeNCM endow them with excellent catalytic activity that is superior to state-of-the-art commercial Pt/C catalyst. It also has long-term operational stability for hydrazine oxidation reaction in practical hydrazine fuel cell.
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| 4. |
- Wang, Yucheng, et al.
(author)
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Advanced Heteroatom-Doped Porous Carbon Membranes Assisted by Poly(ionic liquid) Design and Engineering
- 2020
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In: Accounts of materials research. - : American Chemical Society (ACS). - 2643-6728. ; 1:1, s. 16-29
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Journal article (peer-reviewed)abstract
- Heteroatom-doped porous carbon membranes (HPCMMs) with a tailor-made pore architecture, chemical composition, atomic structural order, and surface state represent an exciting family of porous carbon materials for diverse potential applications in catalysis, water treatment, biofiltration, energy conversion/storage, and so forth. Conventional porous carbon membranes possess intrinsic structural integrity, interconnectivity, and chemical purity across the atomic-to-macro world and have been popularly incorporated into devices as separators or chemically inert conductive supports, circumventing otherwise the inevitable complicated processing and structure weakness of their fine powderous counterpart. Motivated by the distinguished heteroatom-doping effect that revolutionizes the chemical and physical nature of carbon materials, the HPCMM research surges very recently, and focuses not only on the eminent conductive supports or separators but also on electro(co)catalysts in energy devices. Synergy of the porous nature, incorporation of heteroatoms, and the membrane state creates a vivid profile pattern and new task-specific usage. It is also noteworthy that the inherent structural merits of HPCMMs plus a high electron conductivity imbue them as a reliable binder-free model electrode to derive the intrinsic structure-property relationship of porous carbons in electrochemical environments, excluding the complex and adverse factors in association with polymer binders in carbon powder-based electrodes. HPCMMs are of both intense academic interest and practical value because of their well-defined properties endowed by controllable structure and porosity at both atomic and macroscopic scales in a membrane form. The sole aim of this article is to bring this group of porous carbon materials to the forefront so their comprehensive properties and functions can be better understood to serve the carbon community to address pressing materials challenges in our society.In this Account, we highlight the latest discovery and proceedings of HPCMMs, particularly the advancements in how to tailor structures and properties of HPCMMs by rational structure design of porous polymer membranes as sacrificial template built up especially from heteroatom-rich poly(ionic liquid)s (PILs). We will also stress the carbonization craft and the state-of-the-art electrochemical applications for HPCMMs. Key factors and thoughts in heteroatom doping and porous systems in HPCMMs are discussed. A future perspective of the challenges and promising potential of HPCMMs is cast on the basis of these achievements.
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