| 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. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 3. |
- Xu, Hai-Sen, et al.
(författare)
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Single crystal of a one-dimensional metallo-covalent organic framework
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Although polymers have been studied for well over a century, there are few examples of covalently linked polymer crystals synthesised directly from solution. One-dimensional (1D) covalent polymers that are packed into a framework structure can be viewed as a 1D covalent organic framework (COF), but making a single crystal of this has been elusive. Herein, by combining labile metal coordination and dynamic covalent chemistry, we discover a strategy to synthesise single-crystal metallo-COFs under solvothermal conditions. The single-crystal structure is rigorously solved using single-crystal electron diffraction technique. The non-centrosymmetric metallo-COF allows second harmonic generation. Due to the presence of syntactic pendant amine groups along the polymer chains, the metallopolymer crystal can be further cross-linked into a crystalline woven network. Although polymers have been studied for well over a century, there are few examples of covalently linked polymer crystals synthesized directly from solution. Here, the authors demonstrate a strategy to synthesize single crystalline 1D metallo-covalent organic frameworks by combining dynamic covalent chemistry and metal-ligand coordination.
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| 4. |
- Guo, Ming, et al.
(författare)
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The Difference of Serum Protein Transport between Echinosides and Verbascoside
- 2020
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Ingår i: Journal of the Chemical Society of Pakistan. - : The chemical Society of Pakistan. - 0253-5106. ; 42:3, s. 369-382
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Tidskriftsartikel (refereegranskat)abstract
- Verbascoside (VER) is the enzymatic hydrolysis product of echinacoside (ECH). The molecular structures of ECH and VER have different glucosyl groups so they bind to serum albumin in different ways, resulting in different pharmacological actions. In this report, we have examined the binding characteristics between human serum albumin (HSA) and ECH/VER by molecular modeling and spectroscopic approaches. Molecular modeling revealed that VER bound to HSA mainly through hydrogen bonds, van der Waals forces and hydrophobic forces. The spectroscopic results showed that the interactions between HSA and VER/ECH involved a static binding process, and the bonding strength of the VER-HSA complex was stronger than that of the ECH-HSA complex. The value of the binding distances (r) was low, which indicated the occurrence of energy transfer. The reaction conformational pattern of HSA-VER and HSA-ECH gave a "two-state model" based on fluorescent phase diagram analysis. According to the thermodynamic model, the main forces between interaction of VER and HSA were hydrogen bonds and van der Waals forces, whereas the interaction between ECH and HSA was hydrophobic force. The fluorescence polarization analysis demonstrated that the interaction between HSA and VER or ECH generated a non-covalent complex. Compared with ECH, VER was more likely to bind with HSA because of its smaller molecular size and low polarity. The results of the spectral analysis concurred with the molecular modeling data, which provides a helpful reference for the study of the molecular reaction mechanism of VER/ECH binding to HSA.
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| 5. |
- Liang, Huali, et al.
(författare)
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Highly-ordered microstructure and well performance of LiNi0.6Mn0.2Co0.2O2 cathode material via the continuous microfluidic synthesis
- 2020
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 394
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Tidskriftsartikel (refereegranskat)abstract
- Ni-rich layered oxides are potential cathode candidate's materials for Li-ion batteries due to their low cost and high energy density. However, it is difficult to reproducibly prepare uniformly distributed element and wellcontrolled morphology of Ni-rich layered oxide particles. This study develops a continuous microfluidic reaction process to synthesize spherical carbonate precursors (Ni0.6Mn0.2Co0.2CO3). The as-synthesized LiNi0.6Co0.2Mn0.2O2 materials exhibit well-defined microsphere morphology, uniform particles size distribution, better thermal stability and homogeneous transition metal distribution, due to the excellent mixing, well mass and heat transfer rate during the microfluidic reaction. Moreover, the as-prepared LiNi0.6Co0.2Mn0.2O2 materials achieve higher initial capacity, excellent electrochemical reversibility and capacity retention than that of the samples prepared by traditional co-precipitation. Therefore, our results demonstrate that microfluidic reaction is a simple and effective synthesis technology for preparing Ni-rich layered cathode.
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| 6. |
- Luo, Yang, et al.
(författare)
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Three-dimensional and temperature-dependent electronic structure of the heavy-fermion compound CePt2In7 studied by angle-resolved photoemission spectroscopy
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:11
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Tidskriftsartikel (refereegranskat)abstract
- The three-dimensional and temperature-dependent electronic structures of the heavy-fermion superconductor CePt2In7 are investigated. Angle-resolved photoemission spectroscopy using variable photon energy establishes the existence of quasi-two- and three-dimensional Fermi surface topologies. Temperature-dependent 4d-4f on-resonance photoemission spectroscopies data reveal that heavy quasiparticle bands begin to form at a temperature well above the characteristic (coherence) temperature T+. The emergence of low-lying crystal electric field excitation may be responsible for the "relocalization" or the precursor to the establishment of heavy electrons coherence in heavy-fermion compounds. These findings provide critical insight into understanding the hybridization in heavy-fermion systems.
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| 7. |
- Xue, Xiaoyin, et al.
(författare)
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PEDOT:PSS @Molecular Sieve as Dual-Functional Additive to Enhance Electrochemical Performance and Stability of Ni-Rich NMC Lithium-Ion Batteries
- 2020
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Ingår i: Energy Technology. - : Wiley. - 2194-4288 .- 2194-4296. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Molecular sieves (MSs) coated with conductive polymer (PEDOT:PSS) are used as water scavengers to modify the nickel‐rich LiNi1–x–yCoxMnyO2 (NMC)‐layered cathode. This strategy proactively captures residual water in the battery system without affecting the transport performance of electrons and Li+ ions. The moisture content and nuclear magnetic resonance (NMR) tests show that MSs after coating still maintain good water absorption characteristics and inhibit the decomposition of the electrolyte. The conductivity of the PEDOT:PSS@MS‐NMC electrode is 1.08 × 10−4 S cm−1, which is improved by 63.9%, compared with the MS‐NMC electrode. Through X‐ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy measurements, it is also shown that the surface structure stability and particle integrity for PEDOT:PSS@MS‐NMC electrode is well retained. After 500 cycles, the capacity retention of the composite cathode is 71.3%, which is higher than that of the NMC (38.3%) and MS‐NMC cathode (62.4%). This is a novel and effective strategy to suppress side reactions at the electrode interface and improve electrode stability, capacity retention, and cycle performance of the Ni‐rich NMC cathode.
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| 8. |
- Yang, Fu-Sheng, et al.
(författare)
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Chromosome-level genome assembly of a parent species of widely cultivated azaleas
- 2020
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Azaleas (Ericaceae) comprise one of the most diverse ornamental plants, renowned for their cultural and economic importance. We present a chromosome-scale genome assembly for Rhododendron simsii, the primary ancestor of azalea cultivars. Genome analyses unveil the remnants of an ancient whole-genome duplication preceding the radiation of most Ericaceae, likely contributing to the genomic architecture of flowering time. Small-scale gene duplications contribute to the expansion of gene families involved in azalea pigment biosynthesis. We reconstruct entire metabolic pathways for anthocyanins and carotenoids and their potential regulatory networks by detailed analysis of time-ordered gene co-expression networks. MYB, bHLH, and WD40 transcription factors may collectively regulate anthocyanin accumulation in R. simsii, particularly at the initial stages of flower coloration, and with WRKY transcription factors controlling progressive flower coloring at later stages. This work provides a cornerstone for understanding the underlying genetics governing flower timing and coloration and could accelerate selective breeding in azalea. Azaleas are one of the most diverse ornamental plants and have cultural and economic importance. Here, the authors report a chromosome-scale genome assembly for the primary ancestor of the azalea cultivar Rhododendro simsi and identify transcription factors that may function in flower coloration at different stages.
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| 9. |
- Zhai, Pan, et al.
(författare)
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Ionic Conductive Thermoplastic Polymer Welding Layer for Low Electrode/Solid Electrolyte Interface Resistance
- 2020
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 3:7, s. 7011-7019
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Tidskriftsartikel (refereegranskat)abstract
- The application of LAGP ceramic solid electrolytes is circumscribed by the large electrode/electrolyte interfacial resistance because of their rigidity and brittleness. Here, a highly cohesive composite polymer layer consisting of poly(vinylene carbonate)-thermoplastic polyurethanes (PVC-TPU) is coated onto both sides of the Li1.5Al0.5Ge1.5(PO4)(3) pellet to address the interfacial problems with the electrodes. The coated PVC-TPU acts as an ionic conductive welding layer to facilitate the interfacial contact of the LAGP pellet with both electrodes and decreases the interfacial resistance of the LAGP pellet against the cathode (from 1.4 x 10(6) to 3.8 x 10(3) Omega cm(2)) and the Li-metal anode (from 3.3 x 10(4) to 890 Omega cm(2)). The resulting composite solid-state electrolyte (CSSE) presents the synergistic effect of the LAGP ceramic pellet and the PVC-TPU layer in terms of electrochemical stability, ionic transport properties, and stable lithium plating/stripping cycling with a low overpotential for 1000 h. Consequently, the LiFePO4/Li solid-state batteries utilizing this CSSE deliver a high capacity retention of 95.3% after 100 cycles at room temperature with a high Coulombic efficiency exceeding 99.99% per cycle and lithium dendrite inhibition.
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| 10. |
- Zhao, Beibei, et al.
(författare)
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NaSn2(PO4)(3) submicro-particles for high performance Na/Li mixed-ion battery anodes
- 2020
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 844
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Tidskriftsartikel (refereegranskat)abstract
- NaSn2(PO4)(3) has open framework, high ionic conductivity, low working potential, high theoretical capacity more than twice of graphite. However, its commercial application is limited by its low electrical conductivity and rapid capacity fading. To overcome this challenge, we synthesize NaSn2(PO4)(3) submicro-particles (around 100-300 nm in size) by hydrothermally assisted pyrolysis reactions. The synthesized NaSn2(PO4)(3) anode for Na/Li mixed-ion batteries delivers an ultrahigh initial discharge capacities, excellent rate performance and superior cycling stability. This design provides a promising pathway for developing high performance mixed-ion batteries. (C) 2020 Elsevier B.V. All rights reserved.
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