| 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. |
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| 3. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 4. |
- Ching, Tao-Chung, et al.
(författare)
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The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:2
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Tidskriftsartikel (refereegranskat)abstract
- We present 850 mu m dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1-10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6-1.0 mG in the DR21 filament and similar to 0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments.
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| 5. |
- Karoly, Janik, et al.
(författare)
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The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43
- 2023
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 952:1
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Tidskriftsartikel (refereegranskat)abstract
- We present observations of polarized dust emission at 850 mu m from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense (N-H2 similar to 10(22) - 10(23) cm(-2)) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to similar to 160 +/- 30 mu G in the main starless core and up to similar to 90 +/- 40 mu G in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvenic. We also present a new method of data reduction for these denser but fainter objects like starless cores.
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| 6. |
- Wang, Yu-Cheng, et al.
(författare)
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Porous Carbon Membrane-Supported Atomically Dispersed Pyrrole-Type Fe-N-4 as Active Sites for Electrochemical Hydrazine Oxidation Reaction
- 2020
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 16:31
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Tidskriftsartikel (refereegranskat)abstract
- The rational design of catalytically active sites in porous materials is essential in electrocatalysis. Herein, atomically dispersed Fe-N-x sites supported by hierarchically porous carbon membranes are designed to electrocatalyze the hydrazine oxidation reaction (HzOR), one of the key techniques in electrochemical nitrogen transformation. The high intrinsic catalytic activity of the Fe-N-x single-atom catalyst together with the uniquely mixed micro-/macroporous membrane support positions such an electrode among the best-known heteroatom-based carbon anodes for hydrazine fuel cells. Combined with advanced characterization techniques, electrochemical probe experiments, and density functional theory calculation, the pyrrole-type Fe-N-4 structure is identified as the real catalytic site in HzOR.
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| 7. |
- Yang, Junkai, et al.
(författare)
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Tapping ahead of time : its association with timing variability
- 2020
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Ingår i: Psychological Research. - : Springer Berlin/Heidelberg. - 0340-0727 .- 1430-2772. ; 84, s. 343-351
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Tidskriftsartikel (refereegranskat)abstract
- Researchers have puzzled over the phenomenon in sensorimotor timing that people tend to tap ahead of time. When synchronizing movements (e.g., finger taps) with an external sequence (e.g., a metronome), humans typically tap tens of milliseconds before event onsets, producing the elusive negative asynchrony. Here, we present 24 metronome-tapping data sets from 8 experiments with different experimental settings, showing that less negative asynchrony is associated with lower tapping variability. Further analyses reveal that this negative mean-SD correlation of asynchrony is likely to be observed for sequence types appropriate for synchronization, as indicated by the statistically negative lag 1 autocorrelation of inter-response intervals. The reported findings indicate an association between negative asynchrony and timing variability.
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| 8. |
- Chen, Shi-Peng, et al.
(författare)
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Guanidine-based protic ionic liquids as highly efficient intermolecular scissors for dissolving natural cellulose
- 2023
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Ingår i: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 25:22, s. 9322-9334
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Tidskriftsartikel (refereegranskat)abstract
- The development of highly efficient and environmentally friendly solvents for dissolving cellulose, which is the most abundant natural polymer on Earth, remains a challenge, hindering its full utilization. Herein, a green protic ionic liquid, 1,1,3,3-tetramethylguanidinium methoxyacetate ([TMGH][MAA]), was found to exhibit attractive capacity to dissolve natural cellulose with an appropriate TMG/MAA molar ratio of 7 : 3 at 80 degrees C. The solubility of cotton linter and ultra-high molecular weight cotton fibers reached 13% (w/w) and 3% (w/w), respectively, surpassing that of most solvent systems currently used for the dissolution of cellulose. The experimental and simulation results verified that the excellent dissolution ability of [TMGH][MAA] for cellulose is mainly attributed to the destruction of the intrinsic hydrogen-bond networks in cellulose by the synergistic interactions of the [TMGH] cations and [MAA] anions with the hydroxyl groups in the cellulose chains, acting as highly efficient "intermolecular scissors". The superiority of this novel dissolution system was further demonstrated by the remarkable comprehensive properties of the regenerated cellulose film including satisfactory thermostability, high transparency, and excellent mechanical properties. Furthermore, the satisfactory recovery performance of this solvent highlights its significant feasibility for large-scale industrial manufacturing. The proposed [TMGH][MAA] in this study exhibits great potential as a next-generation processing solvent for dissolving, and thus processing cellulose, promoting the sustainable development of high-value-added cellulose materials.
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| 9. |
- Codjia, Jean Evans I., et al.
(författare)
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Morphology, Multilocus Phylogeny, and Toxin Analysis Reveal Amanita albolimbata, the First Lethal Amanita Species From Benin, West Africa
- 2020
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Many species of Amanita sect. Phalloideae (Fr.) Quél. cause death of people after consumption around the world. Amanita albolimbata, a new species of A. sect. Phalloideae from Benin, is described here. The taxon represents the first lethal species of A. sect. Phalloideae known from Benin. Morphology and molecular phylogenetic analyses based on five genes (ITS, nrLSU, rpb2, tef1-α, and β-tubulin) revealed that A. albolimbata is a distinct species. The species is characterized by its smooth, white pileus sometimes covered by a patchy volval remnant, a bulbous stipe with a white limbate volva, broadly ellipsoid to ellipsoid, amyloid basidiospores, and abundant inflated cells in the volva. Screening for the most notorious toxins by liquid chromatography–high-resolution mass spectrometry revealed the presence of α-amanitin, β-amanitin, and phallacidin in A. albolimbata.
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| 10. |
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| 11. |
- Li, Wu Lue, et al.
(författare)
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Multiple Origins and Genomic Basis of Complex Traits in Sighthounds
- 2023
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 40:8
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Tidskriftsartikel (refereegranskat)abstract
- Sighthounds, a distinctive group of hounds comprising numerous breeds, have their origins rooted in ancient artificial selection of dogs. In this study, we performed genome sequencing for 123 sighthounds, including one breed from Africa, six breeds from Europe, two breeds from Russia, and four breeds and 12 village dogs from the Middle East. We gathered public genome data of five sighthounds and 98 other dogs as well as 31 gray wolves to pinpoint the origin and genes influencing the morphology of the sighthound genome. Population genomic analysis suggested that sighthounds originated from native dogs independently and were comprehensively admixed among breeds, supporting the multiple origins hypothesis of sighthounds. An additional 67 published ancient wolf genomes were added for gene flow detection. Results showed dramatic admixture of ancient wolves in African sighthounds, even more than with modern wolves. Whole-genome scan analysis identified 17 positively selected genes (PSGs) in the African population, 27 PSGs in the European population, and 54 PSGs in the Middle Eastern population. None of the PSGs overlapped in the three populations. Pooled PSGs of the three populations were significantly enriched in "regulation of release of sequestered calcium ion into cytosol"(gene ontology: 0051279), which is related to blood circulation and heart contraction. In addition, ESR1, JAK2, ADRB1, PRKCE, and CAMK2D were under positive selection in all three selected groups. This suggests that different PSGs in the same pathway contributed to the similar phenotype of sighthounds. We identified an ESR1 mutation (chr1: g.42,177,149-T > C) in the transcription factor (TF) binding site of Stat5a and a JAK2 mutation (chr1: g.93,277,007-T > A) in the TF binding site of Sox5. Functional experiments confirmed that the ESR1 and JAK2 mutation reduced their expression. Our results provide new insights into the domestication history and genomic basis of sighthounds.
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| 12. |
- Lin, Hao, et al.
(författare)
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Stable and efficient hybrid Ag-In-S/ZnS@SiO2-carbon quantum dots nanocomposites for white light-emitting diodes
- 2020
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 393
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Tidskriftsartikel (refereegranskat)abstract
- As a promising energy-saving technique, the eco-friendly and low-cost solid-state white light-emitting diodes (WLEDs) based on quantum dots (QDs) have been widely studied. Herein, a WLED device prepared by core-shell structure nanocomposites based on Ag-In-S/ZnS@SiO2 quantum dots (AIS@SiO2) and carbon quantum dots (CDs) was successfully constructed. CDs were combined onto the surface of AIS@SiO2 QDs to synthesize Ag-In-S/ZnS@SiO2-Carbon quantum dots (AIS-CDs) nanocomposites with a white-light emission, which successfully overcome the quenching effect of CDs induced by conventional aggregation. The as-prepared AIS-CDs nanocomposites presented high stability and a photoluminescence quantum yield (PLQY) of 35%. Moreover, the corresponding AIS-CDs nanocomposites-based WLEDs demonstrated the color coordinate of (0.32, 0.33), which is comparable to the pure white light (0.33, 0.33); furthermore, the luminous efficiency of the as-prepared WLEDs showed 15.1 lm W-1. These results reported herein may open up a new avenue for the development of high-performance, low-cost, and environmentally-friendly WLEDs.
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| 13. |
- Liu, Chun-Yan, et al.
(författare)
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Massively Parallel Aligned Poly(vinylidene fluoride) Nanofibrils in All-Organic Dielectric Polymer Composite Films for Electric Energy Storage
- 2023
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 56:4, s. 1481-1491
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Tidskriftsartikel (refereegranskat)abstract
- It is a formidable challenge to combine the perform-ance advantages of linear and nonlinear polymer dielectrics for developing all-organic film capacitors with high energy density and low loss. In this work, massively parallel aligned poly(vinylidene fluoride) (PVDF) nanofibrils were in situ fabricated for the first time in the polyethylene (PE) matrix via a multistage stretching technology involving hot stretching and solid-state stretching at an elevated temperature. The largely enhanced interfacial area of PVDF nanofibrils could effectively induce interfacial polarization, imparting PE composite films with a high dielectric constant of 4.50. More interestingly, the nanoconfinement effect of PVDF nanofibrils greatly restricted the migration of free electrons and impurity ions, and an impressive breakdown strength of 624 MV m-1 was obtained. As a result, the as-prepared PE/PVDF composite films exhibited an attractive discharged energy density of as high as 6.4 J cm-3, which was more than 10 times of the conventional counterparts, and outperformed the current linear dielectric polymers. The ingenious structure design of in situ nonlinear dielectric nanofibrils provides a promising approach to maximize the advantageous polarizations and minimize the disadvantageous polarizations in the linear and nonlinear polymer dielectric blends, achieving all-organic polymer dielectric composite films with high energy density and low loss.
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| 14. |
- Lo, Sheng-Han, et al.
(författare)
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Rapid desolvation-triggered domino lattice rearrangement in a metal-organic framework
- 2020
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Ingår i: Nature Chemistry. - : Springer Science and Business Media LLC. - 1755-4330 .- 1755-4349. ; 12:1, s. 90-97
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Tidskriftsartikel (refereegranskat)abstract
- Topological transitions between considerably different phases typically require harsh conditions to collectively break chemical bonds and overcome the stress caused to the original structure by altering its correlated bond environment. In this work we present a case system that can achieve rapid rearrangement of the whole lattice of a metal-organic framework through a domino alteration of the bond connectivity under mild conditions. The system transforms from a disordered metal-organic framework with low porosity to a highly porous and crystalline isomer within 40s following activation (solvent exchange and desolvation), resulting in a substantial increase in surface area from 725 to 2,749m(2)g(-1). Spectroscopic measurements show that this counter-intuitive lattice rearrangement involves a metastable intermediate that results from solvent removal on coordinatively unsaturated metal sites. This disordered-crystalline switch between two topological distinct metal-organic frameworks is shown to be reversible over four cycles through activation and reimmersion in polar solvents. A disordered metal-organic framework converts into a more porous, crystalline phase within 40s following solvent exchange and desolvation. The rapid domino rearrangement of the whole lattice, which involves carboxylate migration on coordinatively unsaturated metal sites, is accompanied by a substantial increase in surface area.
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| 15. |
- 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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| 16. |
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| 17. |
- Yang, J, et al.
(författare)
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Guidelines and definitions for research on epithelial-mesenchymal transition
- 2020
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Ingår i: Nature reviews. Molecular cell biology. - : Springer Science and Business Media LLC. - 1471-0080 .- 1471-0072. ; 21:6, s. 341-352
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Tidskriftsartikel (refereegranskat)abstract
- Epithelial–mesenchymal transition (EMT) encompasses dynamic changes in cellular organization from epithelial to mesenchymal phenotypes, which leads to functional changes in cell migration and invasion. EMT occurs in a diverse range of physiological and pathological conditions and is driven by a conserved set of inducing signals, transcriptional regulators and downstream effectors. With over 5,700 publications indexed by Web of Science in 2019 alone, research on EMT is expanding rapidly. This growing interest warrants the need for a consensus among researchers when referring to and undertaking research on EMT. This Consensus Statement, mediated by ‘the EMT International Association’ (TEMTIA), is the outcome of a 2-year-long discussion among EMT researchers and aims to both clarify the nomenclature and provide definitions and guidelines for EMT research in future publications. We trust that these guidelines will help to reduce misunderstanding and misinterpretation of research data generated in various experimental models and to promote cross-disciplinary collaboration to identify and address key open questions in this research field. While recognizing the importance of maintaining diversity in experimental approaches and conceptual frameworks, we emphasize that lasting contributions of EMT research to increasing our understanding of developmental processes and combatting cancer and other diseases depend on the adoption of a unified terminology to describe EMT.
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| 18. |
- Yang, Sheng, et al.
(författare)
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Generation of skyrmions by combining thermal and spin-orbit torque: breaking half skyrmions into skyrmions
- 2024
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Ingår i: NANOSCALE. - 2040-3364 .- 2040-3372. ; 16, s. 7068-7075
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Tidskriftsartikel (refereegranskat)abstract
- Skyrmions, swirling spin textures with topologically protected stability and low critical driven-current density, can be generated from the stripe domain with current pulses, bringing them closer to practical applications in racetrack memory. However, the mechanism of this topological transition from the stripe domain to the skyrmion remains unclear because the transition process occurs at a nanosecond timescale, giving rise to difficulties in observing this process using imaging tools. In this study, we controlled the domain wall - skyrmion transition by combining Joule heating with spin-orbit torque (SOT) and experimentally observed the details of this process, by which we confirmed the mechanism: the spatial variation of the topological charge density induces half skyrmions branching from the stripe domains, and these half skyrmions overcome the surface tension and break away from the stripe domain, resulting in the generation of skyrmions. The details were observed by employing Joule heating to overcome the pinning effect and manipulating the strength of the SOT to induce the branching and breaking of half skyrmions. These findings offer new insights into skyrmion generation and serve as an important step towards the development of highly efficient devices for processing and computing based on skyrmionics. The study establishes that Joule heating combined with Spin-Orbit Torque (SOT) effectively induces the stripe domain - skyrmion transition in magnetic materials.
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