| 1. |
- Nordin, Matias, 1981, et al.
(författare)
-
Estimation of mass thickness response of embedded aggregated silica nanospheres from high angle annular dark-field scanning transmission electron micrographs
- 2014
-
Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 253:2, s. 166-170
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigate the functional behaviour of the intensity in high-angle annular dark field scanning transmission electron micrograph images. The model material is a silica particle (20 nm) gel at 5 wt%. By assuming that the intensity response is monotonically increasing with increasing mass thickness of silica, an estimate of the functional form is calculated using a maximum likelihood approach. We conclude that a linear functional form of the intensity provides a fair estimate but that a power function is significantly better for estimating the amount of silica in the z-direction. The work adds to the development of quantifying material properties from electron micrographs, especially in the field of tomography methods and three-dimensional quantitative structural characterization from a scanning transmission electron micrograph. It also provides means for direct three-dimensional quantitative structural characterization from a scanning transmission electron micrograph.
|
|
| 2. |
- MacGregor-Ramiasa, M., et al.
(författare)
-
Magnetic alignment of nontronite dispersions
- 2015
-
Ingår i: Applied Clay Science. - : Elsevier BV. - 0169-1317. ; 116-117, s. 167-174
-
Tidskriftsartikel (refereegranskat)abstract
- The time dependent alignment of exfoliated nontronite dispersions subjected to moderate magnetic field strengths (B.
|
|
| 3. |
- Röding, Magnus, 1984, et al.
(författare)
-
Massively parallel approximate Bayesian computation for estimating nanoparticle diffusion coefficients, sizes and concentrations using confocal laser scanning microscopy
- 2018
-
Ingår i: Journal of Microscopy. - : Wiley. - 1365-2818 .- 0022-2720. ; 271:2, s. 174-182
-
Tidskriftsartikel (refereegranskat)abstract
- We implement a massively parallel population Monte Carlo approximate Bayesian computation (PMC‐ABC) method for estimating diffusion coefficients, sizes and concentrations of diffusing nanoparticles in liquid suspension using confocal laser scanning microscopy and particle tracking. The method is based on the joint probability distribution of diffusion coefficients and the time spent by a particle inside a detection region where particles are tracked. We present freely available central processing unit (CPU) and graphics processing unit (GPU) versions of the analysis software, and we apply the method to characterize mono‐ and bidisperse samples of fluorescent polystyrene beads.
|
|
| 4. |
- Röding, Magnus, 1984, et al.
(författare)
-
The gamma distribution model for pulsed-field gradient NMR studies of molecular-weight distributions of polymers
- 2012
-
Ingår i: Journal of Magnetic Resonance. - : Elsevier BV. - 1090-7807 .- 1096-0856. ; 222, s. 105-111
-
Tidskriftsartikel (refereegranskat)abstract
- Self-diffusion in polymer solutions studied with pulsed-field gradient nuclear magnetic resonance (PFG NMR) is typically based either on a single self-diffusion coefficient, or a log-normal distribution of self-diffusion coefficients, or in some cases mixtures of these. Experimental data on polyethylene glycol (PEG) solutions and simulations were used to compare a model based on a gamma distribution of self-diffusion coefficients to more established models such as the single exponential, the stretched exponential, and the log-normal distribution model with regard to performance and consistency. Even though the gamma distribution is very similar to the log-normal distribution, its NMR signal attenuation can be written in a closed form and therefore opens up for increased computational speed. Estimates of the mean self-diffusion coefficient, the spread, and the polydispersity index that were obtained using the gamma model were in excellent agreement with estimates obtained using the log-normal model. Furthermore, we demonstrate that the gamma distribution is by far superior to the log-normal, and comparable to the two other models, in terms of computational speed. This effect is particularly striking for multi-component signal attenuation. Additionally, the gamma distribution as well as the log-normal distribution incorporates explicitly a physically plausible model for polydispersity and spread, in contrast to the single exponential and the stretched exponential. Therefore, the gamma distribution model should be preferred in many experimental situations.
|
|
| 5. |
- Steglich, Thomas, 1983, et al.
(författare)
-
Microstructure and water distribution of commercial pasta studied by microscopy and 3D magnetic resonance imaging
- 2014
-
Ingår i: Food Research International. - : Elsevier BV. - 0963-9969 .- 1873-7145. ; 62, s. 644-652
-
Tidskriftsartikel (refereegranskat)abstract
- Manufacturing pasta is a rather well known process, but it is still challenging to tailor pasta products with new raw materials. In this study, we evaluated the effects of raw materials on the microstructure and water distribution in cooked pasta using H-1 magnetic resonance imaging (MRI) as well as bright field and polarized light microscopy. The MRI parameters initial intensity (I-0) and transverse dephasing time (T-2*) serve as indicators of the local water concentration and water-macromolecule interactions through chemical exchange, respectively. These parameters were mapped throughout the whole pasta volume with a spatial resolution of 78 mu m in all three dimensions. MRI was combined with light microscopy to link I-0 and T-2* to microstructure components such as fiber particles and the extent of starch gelatinization. Four commercial spaghetti samples were analyzed which were made of durum wheat flour, both plain and enriched with wheat fiber, as well as with wholegrain and soft wheat flour. Although all pasta samples showed similar macroscopic water absorption as measured by weight increase, the sample structures differed at the microscopic scale. Compared to durum wheat spaghetti, the presence of fiber particles decreased T-2*, while spaghetti enriched with soft wheat flour increased T-2*. In addition, light microscopy showed that large fiber particles partly acted as barriers against water migration and protected starch granules from swelling. Smaller wheat fiber particles did not affect local starch swelling. Thus, the combination of light microscopy and MRI is a powerful tool to study the microstructure and water distribution in pasta.
|
|
| 6. |
- Townsend, Philip, 1991, et al.
(författare)
-
Tessellation-based stochastic modelling of 3D coating structures imaged with FIB-SEM tomography
- 2021
-
Ingår i: Computational Materials Science. - : Elsevier BV. - 0927-0256 .- 1879-0801. ; 197
-
Tidskriftsartikel (refereegranskat)abstract
- To facilitate printing, coatings are typically applied to paperboard used for packaging to provide a good surface for application. To optimise the performance of the coating, it is important to understand the relationship between the microstructure of the material and its mass transport properties. In this work, three samples of paperboard coating are imaged using combined focused ion beam and scanning electron microscope (FIB-SEM) tomography data appropriately segmented to characterise the internal microstructure. These images are used to inform a parametric, tessellation-based stochastic three-dimensional model intended to mimic the irregular geometry of the particles that can be seen in the coating. Parameters for the model are estimated from the FIBSEM image data, and we demonstrate good agreement between the real and virtual structures both in terms of geometrical measures and mass transport properties. The development of this model facilitates exploration of the relationship between the structure and its properties.
|
|
| 7. |
- Bernin, Diana, 1979, et al.
(författare)
-
Multi-scale characterization of pasta during cooking using microscopy and real-time magnetic resonance imaging
- 2014
-
Ingår i: Food Research International. - : Elsevier BV. - 0963-9969 .- 1873-7145. ; 66, s. 132-139
-
Tidskriftsartikel (refereegranskat)abstract
- Macroscopic properties of pasta, such as the texture, are formed during cooking by a complex interplay of water and heat with the structuring agents starch and gluten. The impact of the starch-to-gluten ratio on microstructure and water distribution in pasta was analyzed by a multi-scale approach combining magnetic resonance imaging (MRI) and light microscopy. The cooking process and thus the water distribution was monitored non-invasively using 1H MRI in real-time with a temporal resolution of 45s. Our MRI set-up allowed following the water ingress by imaging the reduction of the uncooked core. The water ingress rate was neither dependent on pasta composition nor on the presence of salt in the cooking media (0.7% NaCl). Starch-rich samples showed a more homogeneous water distribution in the gelatinized zone, which was mirrored in a more homogeneous microstructure. In contrast, gluten-rich samples showed both a heterogeneous water distribution and microstructure. Thus, the gluten content affected local water content in the gelatinized zone but not the water ingress. © 2014 Elsevier Ltd.
|
|
| 8. |
- Carmona, Pierre, 1995, et al.
(författare)
-
Controlling the structure of spin-coated multilayer ethylcellulose/ hydroxypropylcellulose films for drug release
- 2023
-
Ingår i: International Journal of Pharmaceutics. - 0378-5173 .- 1873-3476. ; 644
-
Tidskriftsartikel (refereegranskat)abstract
- Porous phase-separated ethylcellulose/hydroxypropylcellulose (EC/HPC) films are used to control drug transport out of pharmaceutical pellets. Water-soluble HPC leaches out and forms a porous structure that controls the drug transport. Industrially, the pellets are coated using a fluidized bed spraying device, and a layered film exhibiting varying porosity and structure after leaching is obtained. A detailed understanding of the formation of the multilayered, phase-separated structure during production is lacking. Here, we have investigated multilayered EC/HPC films produced by sequential spin-coating, which was used to mimic the industrial process. The effects of EC/HPC ratio and spin speed on the multilayer film formation and structure were investigated using advanced microscopy techniques and image analysis. Cahn-Hilliard simulations were performed to analyze the mixing behavior. A gradient with larger structures close to the substrate surface and smaller structures close to the air surface was formed due to coarsening of the layers already coated during successive deposition cycles. The porosity of the multilayer film was found to vary with both EC/HPC ratio and spin speed. Simulation of the mixing behavior and in situ characterization of the structure evolution showed that the origin of the discontinuities and multilayer structure can be explained by the non-mixing of the layers.
|
|
| 9. |
- Deschout, H., et al.
(författare)
-
Disposable microfluidic chip with integrated light sheet illumination enables diagnostics based on membrane vesicles
- 2014
-
Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. - 9781632666246
-
Konferensbidrag (refereegranskat)abstract
- Cell-derived membrane vesicles that are released in body fluids are emerging as potential non-invasive biomarkers for diseases like cancer. Techniques capable of measuring the size and concentration of such membrane vesicles directly in body fluids are urgently needed. Here we report on a microfluidic chip with integrated light sheet illumination, and demonstrate accurate fluorescence Single Particle Tracking measurements of the size and concentration of membrane vesicles in cell culture medium and in interstitial fluid collected from primary human breast tumours.
|
|
| 10. |
- Deschout, Hendrik, et al.
(författare)
-
Disposable microfluidic chip with integrated light sheet illumination enables diagnostics based on membrane vesicles
- 2013
-
Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013; Freiburg; Germany; 27 October 2013 through 31 October 2013. ; 3, s. 2010-2012
-
Konferensbidrag (refereegranskat)abstract
- Cell-derived membrane vesicles that are released in body fluids are emerging as potential non-invasive biomarkers for diseases like cancer. Techniques capable of measuring the size and concentration of such membrane vesicles directly in body fluids are urgently needed. Here we report on a microfluidic chip with integrated light sheet illumination, and demonstrate accurate fluorescence Single Particle Tracking measurements of the size and concentration of membrane vesicles in cell culture medium and in interstitial fluid collected from primary human breast tumours.
|
|
