| 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. |
- He, Chengliang, et al.
(författare)
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Asymmetric electron acceptor enables highly luminescent organic solar cells with certified efficiency over 18%
- 2022
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Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing the luminescence property without sacrificing the charge collection is one key to high-performance organic solar cells (OSCs), while limited by the severe non-radiative charge recombination. Here, we demonstrate efficient OSCs with high luminescence via the design and synthesis of an asymmetric non-fullerene acceptor, BO-5Cl. Blending BO-5Cl with the PM6 donor leads to a record-high electroluminescence external quantum efficiency of 0.1%, which results in a low non-radiative voltage loss of 0.178 eV and a power conversion efficiency (PCE) over 15%. Importantly, incorporating BO-5Cl as the third component into a widely-studied donor:acceptor (D:A) blend, PM6:BO-4Cl, allows device displaying a high certified PCE of 18.2%. Our joint experimental and theoretical studies unveil that more diverse D:A interfacial conformations formed by asymmetric acceptor induce optimized blend interfacial energetics, which contributes to the improved device performance via balancing charge generation and recombination. High-performance organic solar cells call for novel designs of acceptor molecules. Here, He et al. design and synthesize a non-fullerene acceptor with an asymmetric structure for diverse donor:acceptor interfacial conformations and report a certificated power conversion efficiency of 18.2%.
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| 3. |
- Ji, Jiadong, et al.
(författare)
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Detection for pathway effect contributing to disease in systems epidemiology with a case-control design
- 2015
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 5:1, s. e006721-
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Identification of pathway effects responsible for specific diseases has been one of the essential tasks in systems epidemiology. Despite some advance in procedures for distinguishing specific pathway (or network) topology between different disease status, statistical inference at a population level remains unsolved and further development is still needed. To identify the specific pathways contributing to diseases, we attempt to develop powerful statistics which can capture the complex relationship among risk factors. Setting and participants: Acute myeloid leukaemia (AML) data obtained from 133 adults (98 patients and 35 controls; 47% female). Results: Simulation studies indicated that the proposed Pathway Effect Measures (PEM) were stable; bootstrap-based methods outperformed the others, with bias-corrected bootstrap CI method having the highest power. Application to real data of AML successfully identified the specific pathway (Treg -> TGF beta -> Th17) effect contributing to AML with p values less than 0.05 under various methods and the bias-corrected bootstrap CI (-0.214 to -0.020). It demonstrated that Th17-Treg correlation balance was impaired in patients with AML, suggesting that Th17-Treg imbalance potentially plays a role in the pathogenesis of AML. Conclusions: The proposed bootstrap-based PEM are valid and powerful for detecting the specific pathway effect contributing to disease, thus potentially providing new insight into the underlying mechanisms and ways to study the disease effects of specific pathways more comprehensively.
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| 4. |
- Li, Chao, et al.
(författare)
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Non-fullerene acceptors with branched side chains and improved molecular packing to exceed 18% efficiency in organic solar cells
- 2021
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Ingår i: Nature Energy. - : NATURE RESEARCH. - 2058-7546.
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Tidskriftsartikel (refereegranskat)abstract
- Molecular design of acceptor and donor molecules has enabled major progress in organic photovoltaics. Li et al. show that branched alkyl chains in non-fullerene acceptors allow favourable morphology in the active layer, enabling a certified device efficiency of 17.9%. Molecular design of non-fullerene acceptors is of vital importance for high-efficiency organic solar cells. The branched alkyl chain modification is often regarded as a counter-intuitive approach, as it may introduce an undesirable steric hindrance that reduces charge transport in non-fullerene acceptors. Here we show the design and synthesis of a highly efficient non-fullerene acceptor family by substituting the beta position of the thiophene unit on a Y6-based dithienothiophen[3,2-b]-pyrrolobenzothiadiazole core with branched alkyl chains. It was found that such a modification to a different alkyl chain length could completely change the molecular packing behaviour of non-fullerene acceptors, leading to improved structural order and charge transport in thin films. An unprecedented efficiency of 18.32% (certified value of 17.9%) with a fill factor of 81.5% is achieved for single-junction organic solar cells. This work reveals the importance of the branched alkyl chain topology in tuning the molecular packing and blend morphology, which leads to improved organic photovoltaic performance.
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| 5. |
- Li, Shian, et al.
(författare)
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Pore-scale study of two-phase flow in the gas diffusion layer of proton exchange membrane fuel cells : The impact of polytetrafluoroethylene content and gradient distribution
- 2024
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Ingår i: Materials Today Communications. - 2352-4928. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- The polytetrafluoroethylene (PTFE) is commonly used to improve the hydrophobic of the gas diffusion layer (GDL). In this study, impacts of PTFE content and piecewise/linear gradient distributions on the transport behavior of liquid water were numerically studied by using a multiphase lattice Boltzmann method. A two-dimensional microstructure of the GDL was reconstructed by stochastic algorithm. The two-phase flow in the GDLs with PTFE contents of 0, 10, 20, 30 and 40 wt% were evaluated and compared. The liquid water transport process can be greatly affected by the PTFE content and the best water drainage performance was provided by the GDL with PTFE content of 30 wt%. Subsequently, the GDLs with PTFE piecewise/linear gradient distributions were designed and investigated. It was found that the water drainage performance can be further improved when the PTFE content is well distributed. This study can provide guidelines for design of GDL for high performance proton exchange membrane fuel cells.
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| 6. |
- Pang, Xiaoying, et al.
(författare)
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The Present-day Mass Function of Star Clusters in the Solar Neighborhood
- 2024
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 966:2
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Tidskriftsartikel (refereegranskat)abstract
- This work analyzes the present-day mass function (PDMF) of 93 star clusters utilizing Gaia Data Release 3 data, with membership determined by the StarGo machine-learning algorithm. The impact of unresolved binary systems on mass estimation is rigorously assessed, adopting three mass ratio profiles for correction. The PDMF is characterized by the power-law index, α, derived through a robust maximum likelihood method that avoids biases associated with data binning. The value of α for stars between the completeness limited mass of Gaia (with a mean 0.3 M⊙ for our cluster samples) and 2 M⊙ exhibits stability for clusters younger than 200 Myr, decreasing for older clusters, particularly when considering stars within the half-mass radius. The PDMF of these star clusters is consistent with a dynamically evolved Kroupa initial mass function via the loss of low-mass stars. Cluster morphology shows a correlation with α, as α values exhibit a decreasing trend from filamentary to tidal-tail clusters, mirroring the sequence of increasing cluster age. The dependence of α on the total cluster mass is weak, with a subtle increase for higher-mass clusters, especially outside the half-mass radius. We do not observe a correlation between α and the mean metallicity of the clusters. Younger clusters have lower metallicity compared to their older counterparts, which indicates that the older clusters might have migrated to the solar neighborhood from the inner disk. A comparison with numerical models incorporating a black hole population suggests the need for observations of distant, older, massive open clusters to determine whether or not they contain black holes.
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