| 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. |
- Aad, G., et al.
(author)
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- 2012
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swepub:Mat__t (peer-reviewed)
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| 3. |
- Zhang, Tianmeng, et al.
(author)
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Observations of a Fast-expanding and UV-bright Type Ia Supernova SN 2013gs
- 2019
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 872:1
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Journal article (peer-reviewed)abstract
- In this paper, we present extensive optical and ultraviolet (UV) observations of the type Ia supernova (SN Ia) 2013gs discovered during the Tsinghua-NAOC Transient Survey. The photometric observations in the optical show that the light curves of SN 2013gs are similar to those of normal SNe Ia, with an absolute peak magnitude of M-B = -19.25 +/- 0.15 mag and a post-maximum decline rate Delta m(15)(B) = 1.00 +/- 0.05 mag. Gehrels Swift Ultr-Violet/Optical Telescope observations indicate that SN 2013gs shows unusually strong UV emission (especially in the uvw1 band) at around the maximum light (M-uvw1 similar to -18.9 mag). The SN is characterized by relatively weak Fe II III absorptions at similar to 5000 angstrom in the early spectra and a larger expansion velocity (v(Si) similar to 13,000 km s(-1) around the maximum light) than the normal-velocity SNe Ia. We discuss the relation between the uvw1 - v color and some observables, including Si II velocity, line strength of Si II lambda 6355 and Fe II/III lines, and Delta m(15)(B). Compared to other fast-expanding SNe Ia, SN 2013gs exhibits Si and Fe absorption lines with similar strength and bluer uvw1 - v color. We briefly discussed the origin of the observed UV dispersion of SNe Ia.
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| 4. |
- Cheng, Qiaoyun, et al.
(author)
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The conversion of nanocellulose into solvent-free nanoscale liquid crystals by attaching long side-arms for multi-responsive optical materials
- 2020
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In: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 8:32, s. 11022-11031
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Journal article (peer-reviewed)abstract
- Nanocellulose, with its unique optical and chemical properties, has received increasing attention as feedstock to fabricate sustainable materials. However, achieving a nanocellulose-based solvent-free liquid crystal with good responsiveness still remains a challenge. Herein, for the first time, solvent-free supramolecular liquid crystals were fabricated by attaching long side-arms on the fiber-like nanocellulose derived from tunicate (TCNC) with an average width of 20 nm and 400-3000 nm in length. The side-arms were grafted via surface condensation with a charged organosilane, followed by further functionalization with a counter-ion polyoxyethylene ether. The nanoscale liquid crystals consisted of the stiff TCNC as the core and flexible side-arms as the soft shells, forming the core-shell structure with an average width of 34-36 nm. The resulting solvent-free liquid crystal exhibited transparent and viscous liquid-like fluidity, as well as a bright birefringence between the crossed polarizers at room temperature. In our findings, the stiff core provided crystal-like ordering, whereas the soft shells induced the high mobility of the TCNCs as a result of the increased fractional free volume, as shown by positron annihilation lifetime spectra. The unique flowability enables the possibility of multi-responsiveness to temperature, deformation, and alternating electric fields. In addition, the thermo-responsiveness can be regulated by tailoring the canopy. This work provides a novel strategy for the conversion of solid nanocellulose into a solvent-free nanoscale liquid crystal, which is promising for use as a responsive optical material.
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| 5. |
- Li, Junhao, et al.
(author)
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Full-color enhanced second harmonic generation using rainbow trapping in ultrathin hyperbolic metamaterials
- 2021
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Journal article (peer-reviewed)abstract
- Though metamaterials enhance nonlinear light-matter interactions due to their resonant features, these materials typically show a narrow spectral bandwidth. Here, the authors report broadband enhanced second-harmonic generation in patterned multilayer hyperbolic metamaterial arrays. Metasurfaces have provided a promising approach to enhance the nonlinearity at subwavelength scale, but usually suffer from a narrow bandwidth as imposed by sharp resonant features. Here, we counterintuitively report a broadband, enhanced second-harmonic generation, in nanopatterned hyperbolic metamaterials. The nanopatterning allows the direct access of the mode with large momentum, rendering the rainbow light trapping, i.e. slow light in a broad frequency, and thus enhancing the local field intensity for boosted nonlinear light-matter interactions. For a proof-of-concept demonstration, we fabricated a nanostructured Au/ZnO multilayer, and enhanced second harmonic generation can be observed within the visible wavelength range (400-650 nm). The enhancement factor is over 50 within the wavelength range of 470-650 nm, and a maximum conversion efficiency of 1.13x10(-6) is obtained with a pump power of only 8.80 mW. Our results herein offer an effective and robust approach towards the broadband metasurface-based nonlinear devices for various important technologies.
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| 6. |
- Li, Yi, et al.
(author)
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Promoting photocatalytic hydrogen evolution by modulating the electron-transfer in an ultrafast timescale through Mo-S6 configuration
- 2024
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In: Journal of Materials Science and Technology. - 1005-0302. ; 193, s. 73-80
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Journal article (peer-reviewed)abstract
- Maximizing ultrafast electron-transfer kinetics in semiconductor is pivotal but challenging for high-efficiency solar-to-energy during the photocatalytic reaction process due to the intrinsic property of photocatalysts with low surface electron density. Herein, a model photocatalyst CdS@Mo is synthesized through a typical hydrothermal method for modulating the ultrafast electron-transfer to enhance the surface electron density. X-ray absorption fine spectra (XAFS) reveal that Mo is coordinated with S atoms to form a Mo-S6 configuration which is different from common MoS2 and Mo foil structures. Based on the femtosecond transient absorption spectra (fs-TAS), it is found that the formation of Mo-S6 configuration contributes to the fast decay of CdS signal and Mo-S6 signal reactivation, illustrating the ultrafast electron-transfer (∼2.2 ps) from CdS to Mo-S6 configuration, which achieves the enhanced electron density of photocatalyst surface. Finally, a holistic photocatalytic performance evaluation discloses that the growing of Mo-S6 configuration obviously improves the photocatalytic hydrogen evolution (PHE) efficiency of CdS from 28.5 to 47.5 mmol g–1 h–1 with a solar-to-hydrogen (STH) efficiency of 0.10 % which is seldomly discussed in the system containing sacrificial agents. This work opens a new path to modulate the surface electron density by tuning the ultrafast electron-transfer for enhancing reaction efficiency in electron-density-dependent systems.
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| 7. |
- Liu, Yueqiang, 1971, et al.
(author)
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ELM control with RMP: Plasma response models and the role of edge peeling response
- 2016
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In: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 58:11, s. Art. no. 114005-
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Journal article (peer-reviewed)abstract
- Resonant magnetic perturbations (RMP) have extensively been demonstrated as a plausible technique for mitigating or suppressing large edge localized modes (ELMs). Associated with this is a substantial amount of theory and modelling efforts during recent years. Various models describing the plasma response to the RMP fields have been proposed in the literature, and are briefly reviewed in this work. Despite their simplicity, linear response models can provide alternative criteria, than the vacuum field based criteria, for guiding the choice of the coil configurations to achieve the best control of ELMs. The role of the edge peeling response to the RMP fields is illustrated as a key indicator for the ELM mitigation in low collisionality plasmas, in various tokamak devices.
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| 8. |
- Peng, Ningxin, et al.
(author)
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Platelet mitochondrial DNA methylation : A novel biomarker for myocardial infarction – A preliminary study
- 2023
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In: International Journal of Cardiology. - 0167-5273.
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Journal article (peer-reviewed)abstract
- Background: Platelet activation and thrombus formation play critical roles in the pathogenesis of myocardial infarction (MI). In addition to their role in energy production, platelet mitochondria also regulate cellular functions related to apoptosis, oxidative stress, and inflammation. Epigenetic modifications of platelet mitochondrial DNA (mtDNA) may influence platelet function and are believed to be an important factor in MI. Therefore, the aim of this study was to investigate the differences in platelet mtDNA methylation levels between MI patients and controls. Methods: The present study utilized propensity score matching to generate 45 multivariate matched apparently healthy controls for 45 patients with newly-onset acute MI. Platelet mtDNA methylation levels were assessed through bisulfite-PCR pyrosequencing and compared between the two groups, with further adjustments made in the sensitivity analysis. Results: Among the measured mitochondrial genes (MT-COX1, MT-COX2, MT-COX3, MT-ND5, MT-ATP6 and tRNA_Leu), patients with MI exhibited statistically significant differences in mtDNA methylation levels as compared to matched controls. Specifically, higher levels of mtDNA methylation were observed in MT-COX1, MT-COX3, and tRNA_Leu, while a lower level was observed in MT-ATP6 (all p < 0.0001). These results remained robust in the sensitivity analysis. Conclusion: Our study demonstrated significant variations in platelet mtDNA methylation levels between patients with MI and controls. Platelet mtDNA methylation may serve as a novel biomarker for MI. This observation also provided some insights into the etiology of MI.
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| 9. |
- Yang, Xu, et al.
(author)
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Modelling of plasma response to 3D external magnetic field perturbations in EAST
- 2016
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In: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 58:11, s. 114006-
-
Journal article (peer-reviewed)abstract
- Sustained mitigation and/or suppression of type-I edge localized modes (ELMs) has been achieved in EAST high-confinement plasmas, utilizing the resonant magnetic perturbation (RMP) fields produced by two rows of magnetic coils located just inside the vacuum vessel. Systematic toroidal modelling of the plasma response to these RMP fields with various coil configurations (with dominant toroidal mode number n = 1, 2, 3, 4) in EAST is, for the first time, carried out by using the MARS-F code (Liu et al 2000 Phys. Plasmas 7 3681), with results reported here. In particular, the plasma response is computed with varying coil phasing (the toroidal phase difference of the coil currents) between the upper and lower rows of coils, from 0 to 360°. Four figures of merit, constructed based on the MARS-F computations, are used to determine the optimal coil phasing. The modelled results, taking into account the plasma response, agree well with the experimental observations in terms of the coil phasing for both the mitigated and the suppressed ELM cases in EAST experiments. This study provides a crucial confirmation of the role of the plasma edge peeling response in ELM control, complementing similar studies carried out for other tokamak devices.
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| 10. |
- Zhou, Lina, et al.
(author)
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Machine Learning on Big Data : Opportunities and Challenges
- 2017
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In: Neurocomputing. - : Elsevier. - 0925-2312 .- 1872-8286. ; 237, s. 350-361
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Journal article (peer-reviewed)abstract
- Machine learning (ML) is continuously unleashing its power in a wide range of applications. It has been pushed to the forefront in recent years partly owing to the advert of big data. ML algorithms have never been better promised while challenged by big data. Big data enables ML algorithms to uncover more fine-grained patterns and make more timely and accurate predictions than ever before; on the other hand, it presents major challenges to ML such as model scalability and distributed computing. In this paper, we introduce a framework of ML on big data (MLBiD) to guide the discussion of its opportunities and challenges. The framework is centered on ML which follows the phases of preprocessing, learning, and evaluation. In addition, the framework is also comprised of four other components, namely big data, user, domain, and system. The phases of ML and the components of MLBiD provide directions for the identification of associated opportunities and challenges and open up future work in many unexplored or under explored research areas.
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