| 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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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Zhou, Shuxing, et al.
(författare)
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Bi-induced highly n-type carbon-doped InGaAsBi films grown by molecular beam epitaxy
- 2018
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 53:5, s. 3537-3543
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-doped InGaAsBi films on InP/Fe (100) substrates have been grown by molecular beam epitaxy (MBE). It has been found that Bismuth incorporation induces extremely high n-type carbon-doped InGaAsBi films, and its electron concentration increases linearly up to 10(21) cm(-3) (highest reported to date for n-type III-V semiconductor materials) with increased CBr4 supply pressure, implying InGaAsBi to be a prospective ohmic contact material for InP-based terahertz transistors. It also has been proved by secondary ion mass spectroscopy that the alloy composition of carbon-doped InGaAsBi is altered by the preferential etching effect of CBr4, but the etching effect on the Bi content is negligible. ERNATHY CR, 1995, APPLIED PHYSICS LETTERS, V66, P1632
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| 4. |
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| 5. |
- Larsson, Mikael, 1982, et al.
(författare)
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Different types of microfibrillated cellulose as filler materials in polysodium acrylate superabsorbents
- 2011
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Ingår i: Chinese Journal of Polymer Science (English Edition). - : Springer Science and Business Media LLC. - 1439-6203 .- 0256-7679. ; 29:4, s. 407-413
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Tidskriftsartikel (refereegranskat)abstract
- Three types of microfibrillated cellulose (MFC) with differences in structure and surface charge were used at low concentration as filler materials in polysodium acrylate superabsorbents (SAPs). The swelling of the composite hydrogels was determined in 0.9% NaCl solution as well as in deionized water. The shear modulus of the samples was determined through uniaxial compression analysis after synthesis and after swelling in 0.9% NaCl solution. Furthermore, the ability to retain filler effects after washing was investigated. The results showed that all of the investigated MFCs had a strong reinforcing effect on the shear modulus after synthesis. The filler effect on swelling and on the associated shear modulus of swollen samples showed a more complicated dependence on structure and surface charge. Finally, it was found that the filler effects were reasonably retained after washing and subsequent drying. The results confirm that MFC holds great potential as a filler material in superabsorbent applications. Furthermore, the results provide some insight on how the structural properties and surface charge of MFC will affect gel properties depending on swelling conditions. This information should be useful in evaluating the use of different types of MFC in future applications.
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| 6. |
- Moberg, Tobias, 1986, et al.
(författare)
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Preparation and Viscoelastic Properties of Composite Fibres Containing Cellulose Nanofibrils : Formation of a Coherent Fibrillar Network
- 2016
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Ingår i: Journal of Nanomaterials. - : Hindawi Publishing Corporation. - 1687-4110 .- 1687-4129. ; 2016
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Tidskriftsartikel (refereegranskat)abstract
- Composite fibres with a matrix of poly(ethylene glycol) (PEG) and cellulose nanofibrils (CNF) as reinforcing elements were produced using a capillary viscometer. Two types of CNF were employed: one based on carboxymethylated pulp fibres and the other on TEMPO-oxidized pulp. Part of the latter nanofibrils was also grafted with PEG in order to improve the compatibility between the CNF and the PEG matrix. The nominal CNF-content was kept at 10 or 30 weight-%. The composite fibres were characterized by optical and scanning electron microscopy in addition to dynamic mechanical thermal analysis (DMTA). Evaluation of the storage modulus indicated a clear reinforcing effect of the CNF, more pronounced in the case of the grafted CNF and depending on the amount of CNF. An interesting feature observed during the DMTA-measurements was that the fibrils within the composite fibres appeared to forma rather coherent and load-bearing network which was evident even after removing of the PEG-phase (by melting). An analysis of the modulus of the composite fibres using a rather simple model indicated that the CNF were more efficient as reinforcing elements at lower concentrations which may be associated with a more pronounced aggregation as the volume fraction of CNF increased.
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| 7. |
- Moberg, Tobias, 1986, et al.
(författare)
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Rheological properties of nanocellulose suspensions : effects of fibril/particle dimensions and surface characteristics
- 2017
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Ingår i: Cellulose. - : Springer Netherlands. - 0969-0239 .- 1572-882X. ; 24:6, s. 2499-2510
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Tidskriftsartikel (refereegranskat)abstract
- The rheological properties of aqueous suspensions based on three different nanocelluloses were compared. One system was obtained via acid hydrolysis (thus yielding crystalline nanocellulose, CNC) and the other two from mechanical shearing, but from different origins and subjected to different pretreatments. Of the latter two, one was considered to be a rather typical cellulose nanofibril (CNF) suspension whereas the other was a kind of intermediate between CNF and CNC. All three nanocellulose elements differed in dimensions as evident from transmission electron microscopy and atomic force microscopy. With regard to the length of the fibrils/particles, the three nanocelluloses formed three distinct groups with lengths between 200 and slightly more than 800 nm. The three cellulosic elements were also subjected to a TEMPO-mediated oxidation yielding a similar carboxylate content in the three systems. Furthermore, the TEMPO-oxidized elements were grafted with poly(ethylene glycol) (PEG). The amount of grafted PEG was about 35 wt%. The shear viscosity, the storage modulus and the loss modulus of suspensions of the unmodified, the TEMPO-oxidized and the grafted nanocelluloses were determined at room temperature and the solids content of the suspensions was varied between 0.7 and 2.0 wt%. It was concluded that the rheological properties varied significantly between the suspensions depending on the dimensions of the cellulosic elements and their surface characteristics. In this context, the length (or the aspect ratio) of the particles played a very important role.
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| 8. |
- Pelliciari, Jonathan, et al.
(författare)
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Evolution of spin excitations from bulk to monolayer FeSe
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- In ultrathin films of FeSe grown on SrTiO (FeSe/STO), the superconducting transition temperature T is increased by almost an order of magnitude, raising questions on the pairing mechanism. As in other superconductors, antiferromagnetic spin fluctuations have been proposed to mediate SC making it essential to study the evolution of the spin dynamics of FeSe from the bulk to the ultrathin limit. Here, we investigate the spin excitations in bulk and monolayer FeSe/STO using resonant inelastic x-ray scattering (RIXS) and quantum Monte Carlo (QMC) calculations. Despite the absence of long-range magnetic order, bulk FeSe displays dispersive magnetic excitations reminiscent of other Fe-pnictides. Conversely, the spin excitations in FeSe/STO are gapped, dispersionless, and significantly hardened relative to its bulk counterpart. By comparing our RIXS results with simulations of a bilayer Hubbard model, we connect the evolution of the spin excitations to the Fermiology of the two systems revealing a remarkable reconfiguration of spin excitations in FeSe/STO, essential to understand the role of spin fluctuations in the pairing mechanism.
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| 9. |
- Yuan, Chao, et al.
(författare)
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Space charge behavior in silicone rubber from in-service aged HVDC composite insulators
- 2019
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - 1558-4135 .- 1070-9878. ; 26:3, s. 843-850
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Tidskriftsartikel (refereegranskat)abstract
- Space charge behavior in sheds removed from service aged 500 and 800 kV HVDC silicone rubber insulators and compared to a stored reference insulator is reported in this paper. The aim of this investigation is to evaluate the material aging. The investigations are made under electric field of ±20 kV/mm at room temperature using pulsed electro-acoustic technique. Based on the results, the electric field distribution and mobility of charge carriers, considering the contributions of de-trapping process from both shallow and deep traps, are deduced. It is concluded that space charge concentration in the aged material increases compared to that in the reference material and the dynamics of the charge decay changes. The understanding of this behavior provides a means of possibility assessing insulator material aging.
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| 10. |
- Zhou, Mofan, et al.
(författare)
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Improving efficiency at highway T-junctions with connected and automated vehicles
- 2021
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Ingår i: Transportmetrica A: Transport Science. - : Informa UK Limited. - 2324-9943 .- 2324-9935. ; 17:1, s. 107-123
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Tidskriftsartikel (refereegranskat)abstract
- Hong Kong Society for Transportation Studies Limited. The development in communication technologies offers efficient vehicular communication capability. Vehicles in communication with road infrastructure share essential traffic information that can be used to develop cooperative driving strategies. In this paper, we aim to propose a heuristic and cooperative method to improve efficiency and merging capacity for highway T-junctions. We evaluated a few performance indicators including travel time, safety and emission. Results indicate that a significant improvement is observed in comparison with the baseline benchmarking case. We further conducted simulations with different geometric configurations and pointed out a few issues that need to be addressed in order to maximise the benefit.
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