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| 2. |
- 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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| 3. |
- Li, Kexue, et al.
(författare)
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Directional emissions from perovskite nanocrystals thin film enabled by metasurface integration through one step spin-coating process
- 2023
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Ingår i: Nano Research. - : Springer Science and Business Media LLC. - 1998-0124 .- 1998-0000. ; 16:5, s. 7646-7653
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Tidskriftsartikel (refereegranskat)abstract
- Advances in thin film light-emitting devices have fueled the rapid growth of a new class of solid-state lighting devices, featuring low fabrication cost, high quantum efficiency, and broadband spectrum coverage, etc. In contrast to the conventional inorganic semiconductors that rely on lattice matched high crystalline quality substrate, solution processable thin films eliminate the dependence on the substrate, which is highly desired for the ease and versatility of integrations with foreign medium. By taking this advantage, this work developed an ultracompact solution to control the directionality of thin film emitters using integrated dielectric metasurface through one step spin-coating process. As a proof of concept, directional emissions from perovskite nanocrystal thin film, including collimated light emissions and two-dimensional beam steering, are experimentally demonstrated. Notably, our approach, where light emitters were integrated on the back side of substrate after the fabrication of metasurface, judiciously avoids any potential degradation of material optical quality caused by the multi-step nanofabrication. Therefore, it can serve as a generalized scheme to engage the advantageous properties of dielectric metasurface, including the compactness, high efficiency, and beam controllability with the emerging thin film light-emitting diodes (LEDs), which is applicable to a wide range of solution processable materials, including organic light-emitting diodes, quantum-dot light emitting diodes, polymer LEDs, and perovskite LEDs, opening up new pathways to develop low-cost and ultra-compact solid state light sources with versatile beams characteristics. [Figure not available: see fulltext.].
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| 4. |
- Kang, Shuting, et al.
(författare)
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ECSAS : Exploring critical scenarios from action sequence in autonomous driving
- 2023
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Ingår i: Proceeding of 2023 IEEE 32nd Asian Test Symposium (ATS). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Rare critical scenarios are crucial to verify the performance of autonomous driving in different situations. Critical scenario generation requires the ability of sampling critical combinations from an infinite parameter space in the logical scenario. Existing solutions aim to explore the correlation of action parameters in the initial scenario rather than action sequences. How to model action sequences so that one can further consider the effects of different action parameters is the bottleneck of the problem. In this paper, we solve the problem by proposing the ECSAS framework. Specifically, we first propose a description language, BTScenario, allowing us to model action sequences of scenarios. We then use reinforcement learning to search for combinations of critical action parameters. Several optimizations are proposed to increase efficiency, including action mask and replay buffer. Experimental results show that our model with strong collision ability and effectively outperforms the existing methods on various nontrivial scenarios.
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| 5. |
- Liu, Jingyin, et al.
(författare)
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Biomineralization stimulated peri-titanium implants prepared by selective laser melting
- 2015
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Ingår i: Journal of Materiomics. - : Elsevier BV. - 2352-8478 .- 2352-8486. ; 1:3, s. 253-261
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Tidskriftsartikel (refereegranskat)abstract
- Titanium implants prepared by selective laser melting (SLM), a method of additive manufacturing, were subjected to implantation in beagle dogs for two and four weeks. Argon ion beam-polished cross sections of the implants after in vivo tests were characterized by scanning electron microscope (SEM) to evaluate the bone–implant interface and the early peri-implant biomineralization with sufficiently improved resolution. Two bone mineralization mechanisms were disclosed. As early as two weeks after implantation, a layer of new bone was found to form directly on the implant surface and bone in-growth was also observed. Osseointegration was found to establish partly at the tip of the implants. After healing for four weeks it was found that osseointegration was established around the entire tip of the implants, whereas only partly at the third thread region of the implants. The experimental evidences observed reveal that an inherent highly porous surface of the titanium implants generated by selective laser melting is favorable for new bone apposition.
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| 6. |
- Zhang, Tongyu, et al.
(författare)
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Genome-wide association studies revealed candidate genes for tail fat deposition and body size in the Hulun Buir sheep
- 2019
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Ingår i: Journal of Animal Breeding and Genetics. - : WILEY. - 0931-2668 .- 1439-0388. ; 136:5, s. 362-370
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Tidskriftsartikel (refereegranskat)abstract
- Fat-tailed sheep have a unique characteristic of depositing fat in their tails. In the present study, we conducted genome-wide association studies (GWAS) on traits related to tail fat deposition and body size in the Hulun Buir sheep. A total number of 300 individuals belonging to two fat-tailed lines of the Hulun Buir sheep breed genotyped with the Ovine Infinium HD SNP BeadChip were included in the current study. Two mixed models, one for continuous and one for binary phenotypic traits, were employed to analyse ten traits, that is, body length (BL), body height (BH), chest girth (CG), tail length (TL), tail width (TW), tail circumference (TC), carcass weight (CW), tail fat weight (TF), ratio of CW to TF (RCT) and tail type (TT). We identified 7, 6, 7, 2, 10 and 1 SNPs significantly associated with traits TF, CW, RCT, TW, TT and CG, respectively. Their associated genomic regions harboured 42 positional candidate genes. Out of them, 13 candidate genes including SMURF2, FBF1, DTNBP1, SETD7 and RBM11 have been associated with fat metabolism in sheep. The RBM11 gene has already been identified in a previous study on signatures of selection in this specific sheep population. Two more genes, that is, SMARCA5 and GAB1 were associated with body size in sheep. The present study has identified candidate genes that might be implicated in tail fat deposition and body size in sheep.
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| 7. |
- Zhang, Yanjun, et al.
(författare)
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Influence of thermal expansion and wear on the temperatures and stresses in railway disc brakes
- 2024
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Ingår i: International Communications in Heat and Mass Transfer. - : Elsevier BV. - 0735-1933 .- 1879-0178. ; 158
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Tidskriftsartikel (refereegranskat)abstract
- Thermo-mechanical coupled systems are typically complex, however, the demand for analyses of this kind of multi-physics system is increasing, for example, accurately predicting the temperature and thermal stress of the railway disc brakes. However, many models ignore the phenomenon of thermal expansion and wear on brake pads. Therefore, their influence on the result is unclear. This research aims to investigate the effect of these two phenomena on the temperatures and stresses. These influences represent different heat flux input methods. Based on the finite element method (FEM), a three-dimensional (3D) transient thermo-mechanical model is built up. Three cases with or without thermal expansion and wear are conducted. The model is validated against measurement data. Simulation results show that thermal expansion and wear on the brake pads cause a 10% difference in the average temperatures of the brake discs, while a 257% difference in the maximum temperatures. As for the equivalent stresses (Von Mises stress), the difference can reach 3500%. Overall, this research builds a thermo-mechanical model and quantifies the effects of thermal expansion and wear on the temperatures and stresses of railway brake discs. The model can be transferred to other thermo-mechanical coupled multi-physics systems.
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| 8. |
- Zhang, Yanjun, et al.
(författare)
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Study on the braking distance of composite brake blocks covered with ice for freight trains in winter
- 2023
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 237:8, s. 1050-1059
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Tidskriftsartikel (refereegranskat)abstract
- In winter, some freight trains with composite brake blocks experience unexpected long braking distances, which seriously jeopardizes running safety. The reasons for the long braking distances are still not completely understood, and therefore it is difficult to suggest preventive measures. Up to now, it has not really been studied how a layer of ice that is often found between the brake block and the wheel influences the braking process. To investigate whether ice influences the braking distance, a numerical model is built. Ice thickness, ambient temperature, initial speed, and axle load/brake pressure are parameters that can be varied in the model. Results are checked against available on-track tests. The simulation results show that ice significantly influences the braking distance. The impact of ice on the braking distance increases when the ambient temperature, initial speed, and brake pressure are low, which is consistent with available field test reports. The results also show that a conditioning brake, a high brake pressure and a small clearance between the wheel and brake block can efficiently reduce the impact of ice on the braking distance of freight trains with composite brake blocks in winter.
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