| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
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.
|
|
| 2. |
- Li, Shuting, et al.
(författare)
-
Direct structure determination of vemurafenib polymorphism from compact spherulites using 3D electron diffraction
- 2023
-
Ingår i: Communications Chemistry. - : Springer Science and Business Media LLC. - 2399-3669. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- The spherulitic morphology is considered to be the most common morphology of crystalline materials and is particularly apparent in melt-crystallized products. Yet, historically, the polycrystalline nature of spherulites has hindered successful crystal structure determination. Here, we report the direct structure determination of a clinical drug, vemurafenib (VMN), in compact spherulite form using 3D electron diffraction (3D ED). VMN has four known polymorphs. We first solved the crystal structures of α-, β-, and γ-VMN from compact spherulites using 3D ED, and the resulting structures were highly consistent with those obtained by single-crystal X-ray diffraction. We then determined the crystal structure of δ-VMN—the least stable polymorph which cannot be cultivated as a single crystal—directly from the compact spherulite sample. We unexpectedly discovered a new polymorph during our studies, denoted as ε-VMN. Single crystals of ε-VMN are extremely thin and not suitable for study by X-ray diffraction. Again, we determined the structure of ε-VMN in a compact spherulite form. This successful structure elucidation of all five VMN polymorphs demonstrates the possibility of directly determining structures from melt-grown compact spherulite samples. Thereby, this discovery will improve the efficiency and broaden the scope of polymorphism research, especially within the field of melt crystallization.
|
|
| 3. |
- Sun, Yasong, et al.
(författare)
-
Angular-spatial upwind element differential method for radiative heat transfer in a concentric spherical participating medium
- 2022
-
Ingår i: Engineering analysis with boundary elements. - : ELSEVIER SCI LTD. - 0955-7997 .- 1873-197X. ; 144, s. 19-30
-
Tidskriftsartikel (refereegranskat)abstract
- Radiative intensity with high directional and spatial resolutions can provide abundant useful information for combustion diagnosis systems based on radiative images. In this paper, an angular-spatial upwind element differential method (ASUEDM) is developed to discretize angular direction and spatial domain of radiative transfer equation (RTE) in a spherically participating medium. Because of the strong convection characteristic of radiative transfer equation, an upwind scheme is adopted to suppress the numerical oscillation. Meanwhile, Chebyshev-Gauss-Lobatto nodes are used to minimize the effect of the Runge phenomenon. Unlike conductive or convective boundary conditions, radiative boundary condition is unidirectional boundary condition, and a singularity node exists at the boundary. To deal with this singularity, we propose a discontinuous strategy. Three examples of radiative heat transfer in concentric spheres are chosen to test the capability of ASUEDM. Compared with benchmark solutions, ASUEDM can provide higher accuracy than discrete ordinates method or finite volume method. Besides, ASUEDM can flexibly provide hp convergence rate and achieve high-resolution characterization in angular direction and spatial domain.
|
|
| 4. |
- Xu, Yue, et al.
(författare)
-
Pyrrolylmethylene Appended Corrorin: Peripheral Coordination and Transformation to Pyridyl Incorporated Hemiporphycene Analogue
- 2023
-
Ingår i: Organic Letters. - : AMER CHEMICAL SOC. - 1523-7060 .- 1523-7052. ; 25:10, s. 1793-1798
-
Tidskriftsartikel (refereegranskat)abstract
- A pyrrolylmethylene appended corrorin 1 was synthesized and coordinated with [Rh(CO)2Cl]2 to afford 1-Rh with unique RhI-eta 2-CC bonding in addition to the coordination of the dipyrrin-like unit and a carbonyl ligand. Further oxidation of 1 afforded 2, exhibiting a hydrocorrorinone core, and it can be further transformed into pyrrolo[3,2c]pyridine incorporated hemiporphycene analogue 3 upon treatment with HOAc. The side chain modifies the reactivity of corrorin and effectively tunes the NIR absorption of the resulting porphyrinoids.
|
|
| 5. |
- You, Fang, et al.
(författare)
-
Interface Color Design of Intelligent Vehicle Central Console
- 2021
-
Ingår i: Advances in Usability, User Experience, Wearable and Assistive Technology. - Cham : Springer Nature. - 9783030800901 - 9783030800918 ; , s. 784-792
-
Konferensbidrag (refereegranskat)abstract
- The development of intelligent automobiles puts forward higher requirements for HMI design. The information obtained by drivers through vision accounts for 80%. As a key part of visual perception, color affects driving performance. This article investigates vehicle interface design about icon-background contrast. Three colors commonly used in car-machine interface are chosen: red, green and blue, and contrast is divided into five levels under daytime and nighttime. The participants tested three colors and the five contrasts in an experiment using classic paradigm of secondary tasks. We collected data from their driving behavior and subjective experience, trying to find a most appropriate value. The results show that recommended contrast values under different lighting conditions are 3:1 to 4:1 for red, blue, and green during the day; 3:1 for red at night, and 5:1 for blue and green, so that the vehicle central console color design references are formed.
|
|
| 6. |
|
|
| 7. |
- Bai, Yushi, et al.
(författare)
-
Protein nanoribbons template enamel mineralization
- 2020
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 117:32, s. 19201-19208
-
Tidskriftsartikel (refereegranskat)abstract
- As the hardest tissue formed by vertebrates, enamel represents nature's engineering masterpiece with complex organizations of fibrous apatite crystals at the nanometer scale. Supramolecular assemblies of enamel matrix proteins (EMPs) play a key role as the structural scaffolds for regulating mineral morphology during enamel development. However, to achieve maximum tissue hardness, most organic content in enamel is digested and removed at the maturation stage, and thus knowledge of a structural protein template that could guide enamel mineralization is limited at this date. Herein, by examining a gene-modified mouse that lacked enzymatic degradation of EMPs, we demonstrate the presence of protein nanoribbons as the structural scaffolds in developing enamel matrix. Using in vitro mineralization assays we showed that both recombinant and enamel-tissue-based amelogenin nanoribbons are capable of guiding fibrous apatite nanocrystal formation. In accordance with our understanding of the natural process of enamel formation, templated crystal growth was achieved by interaction of amelogenin scaffolds with acidic macromolecules that facilitate the formation of an amorphous calcium phosphate precursor which gradually transforms into oriented apatite fibers along the protein nanoribbons. Furthermore, this study elucidated that matrix metalloproteinase-20 is a critical regulator of the enamel mineralization as only a recombinant analog of a MMP20-cleavage product of amelogenin was capable of guiding apatite mineralization. This study highlights that supramolecular assembly of the scaffold protein, its enzymatic processing, and its ability to interact with acidic carrier proteins are critical steps for proper enamel development.
|
|
| 8. |
- Hu, Guojie, et al.
(författare)
-
Water and heat coupling processes and its simulation in frozen soils : Current status and future research directions
- 2023
-
Ingår i: Catena. - : Elsevier BV. - 0341-8162. ; 222
-
Forskningsöversikt (refereegranskat)abstract
- To date, most studies on coupled-water-and-heat processes in frozen soils haves focused on the mechanism of changes in frozen soil and the contribution of climate change, hydrological processes, and ecosystems in cold regions. Several studies have demonstrated considerable improvements in the accuracy of simulating water and heat transfer processes in cold regions. However, substantial differences remain among the different models and parameterizations because of the lack of observations and in-depth understanding of the water and heat transfer processes. Hence, it is necessary to summarize recent advances in the simulation of water-and-heat-coupling processes and challenges for further research. Therefore, we present a theory-focused summary of progress in this field considering the aspects of water flow and coupled-water-and-heat transfer. The simulation progress is discussed in terms of physical process models; one type of model only considers the heat conduction transfer processes without water flow, and the other considers coupled-water-and-heat transfer processes. Aspects of model deficiencies related to non-conductive heat transfer and soil water transfer processes in the frozen soil are also summarized. Moreover, the major parameterizations are reviewed, including phase changes, freeze–thaw fronts, thermal conductivity, hydraulic conductivity, snow processes, surface parameterization schemes, ground ice, and lower boundary conditions. While models and parameterizations can suitably capture local-scale water and heat transfer processes in frozen soil, their applications are spatiotemporally constrained, requiring further improvement. We provide a theoretical basis for further studying water and heat transfer processes in frozen soil and suggest that future research should enhance the accuracy of frozen soil parameterization and improve the understanding of the coupling of water and heat transfer processes based on improved observation techniques and high-resolution data.
|
|
| 9. |
- Li, Xinmin, et al.
(författare)
-
Molecular dynamics study on friction of the iron-aluminum alloy
- 2022
-
Ingår i: Materials Today Communications. - : Elsevier BV. - 2352-4928. ; 33, s. 104402-
-
Tidskriftsartikel (refereegranskat)abstract
- Iron-aluminum alloy has been widely used in aerospace, nuclear power, electronics and other fields. Taking into account the limitations of the continuum mechanics model at the microscopic scale, it is critical to use nanoscale simulation methods like molecular dynamics (MD) to have a deeper understanding of the friction and wear behavior. Through MD simulation, this thesis mainly studied the friction and wear process of iron aluminum alloy under different conditions. The main conclusions are as follows:(1) The frictional force first experiences a period of growth, and then stabilizes with some fluctuations due to the release of stress-energy caused by deformation.(2) Temperature and friction speed has no significant effect on friction force.(3) The higher the friction speed is, the more wear debris it produces, and the more severely the material is damaged.(4) The force and coefficient of friction will increase with the rise of aluminum content, and the plastic deformation of the alloy is strengthened, while the elastic deformation decreases.(5) The frictional force increases with the wear depth since the accumulation phenomenon of atoms becomes more obvious.
|
|
| 10. |
- Pang, Xiaoying, et al.
(författare)
-
The Present-day Mass Function of Star Clusters in the Solar Neighborhood
- 2024
-
Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 966:2
-
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.
|
|
| 11. |
- Yang, Bin, et al.
(författare)
-
Computer Vision and Machine Learning Methods for Heat Transfer and Fluid Flow in Complex Structural Microchannels : A Review
- 2023
-
Ingår i: Energies. - : MDPI. - 1996-1073. ; 16:3
-
Forskningsöversikt (refereegranskat)abstract
- Heat dissipation in high-heat flux micro-devices has become a pressing issue. One of the most effective methods for removing the high heat load of micro-devices is boiling heat transfer in microchannels. A novel approach to flow pattern and heat transfer recognition in microchannels is provided by the combination of image and machine learning techniques. The support vector machine method in texture characteristics successfully recognizes flow patterns. To determine the bubble dynamics behavior and flow pattern in the micro-device, image features are combined with machine learning algorithms and applied in the recognition of boiling flow patterns. As a result, the relationship between flow pattern evolution and boiling heat transfer is established, and the mechanism of boiling heat transfer is revealed.
|
|
| 12. |
- Yin, Shi, et al.
(författare)
-
Experimental study of thermal plumes generated by a cluster of high-rise compact buildings under moderate background wind conditions
- 2020
-
Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 181
-
Tidskriftsartikel (refereegranskat)abstract
- When background wind is moderate, urban environment may face great challenges as removal ability of airborne pollutants, anthropogenic heat and moisture reduces. Under this condition, buoyancy-driven flow can break the dominant role of the background wind and affect the urban environment greatly. Knowledge of buoyant flow dynamics is essential for understanding urban wind/thermal environment and related pollutant transport. As one important buoyant flow, thermal plumes generated by a cluster of high-rise compact buildings are modelled using a laboratory water channel in this study. Flow similarity, when the buoyancy is prominent, is well satisfied. Mean flows, turbulent statistics, and rising features under different Froude (Fr) numbers are systematically explored by two-dimensional particle image velocimetry (PIV) technique. Overall, the transition of buoyancy-dominated and wind-dominated flow dynamics is observed when Fr number varies. For horizontal and vertical velocity components, peak magnitude and position are quantitatively determined on four building poles. Fr number obviously changes the relative magnitude of v-peak among four poles. Turbulence statistics, including velocity variance, turbulence kinetic energy, power spectral density, turbulent momentum flux, and turbulence production, are systematically analyzed, which show consistent results. As Fr number decreases, the plume mixing is enhanced. When particularly aiming at the plume region, smaller Fr numbers usually make the maximum velocities occur more in the plume central part rather than the boundaries. A quantitative rational function is given to describe the relation between Fr number and the rising angle, as a = 8.76/(Frq + 0.097).
|
|
| 13. |
- You, Fang, et al.
(författare)
-
Icon Design Recommendations for Central Consoles of Intelligent Vehicles
- 2020
-
Ingår i: Human Interaction, Emerging Technologies and Future Applications II. - Cham : Springer. - 9783030442668 - 9783030442675 ; , s. 285-291
-
Konferensbidrag (refereegranskat)abstract
- Advances in vehicle technology open up both opportunities and challenges for human-machine interface (HMI) design in intelligent vehicles. Design guidelines for icons in central consoles of vehicles have been discussed in human-computer interaction community, but more study and innovation are needed in icon design. In this paper, we investigated the displayed line thickness and size of icons in the intelligent vehicle’s central control screen, based on international design guidelines and standards. The experiment involved 17 participants performing simulated in-vehicle secondary task. The result from the experiments shows that the usability of icons increases and the driver’s workload decreases as the icons get larger. We also found a set of recommended values for size and line thickness of icons in this context. Future work will focus on providing design guidelines for other aspects of HMI design in intelligent vehicles.
|
|
| 14. |
- Zhang, Litianyi, et al.
(författare)
-
Enabling Real-Time Quality-of-Service and Fine-Grained Aggregation for Wireless TSN
- 2022
-
Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 22:10
-
Tidskriftsartikel (refereegranskat)abstract
- Wireless Time-Sensitive Networking (WTSN) has emerged as a promising technology for Industrial Internet of Things (IIoT) applications. To meet the latency requirements of WTSN, wireless local area network (WLAN) such as IEEE 802.11 protocol with the time division multiple access (TDMA) mechanism is shown to be a practical solution. In this paper, we propose the RT-WiFiQA protocol with two novel schemes to improve the latency and reliability performance: real-time quality of service (RT-QoS) and fine-grained aggregation (FGA) for TDMA-based 802.11 systems. The RT-QoS is designed to guarantee the quality-of-service requirements of different traffic and to support the FGA mechanism. The FGA mechanism aggregates frames for different stations to reduce the physical layer transmission overhead. The trade-off between the reliability and FGA packet size is analyzed with numerical results. Specifically, we derive a critical threshold such that the FGA can achieve higher reliability when the aggregated packet size is smaller than the critical threshold. Otherwise, the non-aggregation scheme outperforms the FGA scheme. Extensive experiments are conducted on the commercial off-the-shelf 802.11 interface. The experiment results show that compared with the existing TDMA-based 802.11 system, the developed RT-WiFiQA protocol can achieve deterministic bounded real-time latency and greatly improves the reliability performance.
|
|
