| 1. |
- Andersson, Mariam, et al.
(författare)
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Axon morphology is modulated by the local environment and impacts the noninvasive investigation of its structure-function relationship
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 117:52, s. 33649-33659
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Tidskriftsartikel (refereegranskat)abstract
- Axonal conduction velocity, which ensures efficient function of the brain network, is related to axon diameter. Noninvasive, in vivo axon diameter estimates can be made with diffusion magnetic resonance imaging, but the technique requires three-dimensional (3D) validation. Here, high-resolution, 3D synchrotron X-ray nano-holotomography images of white matter samples from the corpus callosum of a monkey brain reveal that blood vessels, cells, and vacuoles affect axonal diameter and trajectory. Within single axons, we find that the variation in diameter and conduction velocity correlates with the mean diameter, contesting the value of precise diameter determination in larger axons. These complex 3D axon morphologies drive previously reported 2D trends in axon diameter and g-ratio. Furthermore, we find that these morphologies bias the estimates of axon diameter with diffusion magnetic resonance imaging and, ultimately, impact the investigation and formulation of the axon structure-function relationship.
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| 2. |
- Oikonomou, Vasileios, et al.
(författare)
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Elucidating the Bulk Morphology of Cellulose-Based Conducting Aerogels with X-Ray Microtomography
- 2023
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Ingår i: Advanced Materials Technologies. - : WILEY. - 2365-709X. ; 8:23
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Tidskriftsartikel (refereegranskat)abstract
- Conducting cellulose composites are promising sustainable functional materials that have found application in energy devices, sensing and water purification. Herein, conducting aerogels are fabricated based on nanofibrillated cellulose and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, using the ice templating technique, and their bulk morphology is characterized with X-ray microtomography. The freezing method (−20 °C in a freezer vs liquid nitrogen) does not impact the mean porosity of the aerogels but the liquid-N2 aerogels have smaller pores. The integration of carbon fibers as addressing electrodes prior to freezing results in increased mean porosity and pore size in the liquid-N2 aerogels signifying that the carbon fibers alter the morphology of the aerogels when the freezing is fast. Spatially resolved porosity and pore size distributions also reveal that the liquid-N2 aerogels are more inhomogeneous. Independent of the freezing method, the aerogels have similar electrochemical properties. For aerogels without carbon fibers, freezer-aerogels have higher compression modulus and are less stable under cycling compression fatigue test. This can be explained by higher porosity with larger pores in the center of liquid-N2 aerogels and thinner pore walls. This work demonstrates that micro-CT is a powerful tool for characterizing the morphology of aerogels in a non-destructive and spatially resolved manner.
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| 3. |
- Tichit, Pierre, et al.
(författare)
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InSegtCone : interactive segmentation of crystalline cones in compound eyes
- 2022
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Ingår i: BMC Zoology. - : Springer Science and Business Media LLC. - 2056-3132. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Understanding the diversity of eyes is crucial to unravel how different animals use vision to interact with their respective environments. To date, comparative studies of eye anatomy are scarce because they often involve time-consuming or inefficient methods. X-ray micro-tomography (micro-CT) is a promising high-throughput imaging technique that enables to reconstruct the 3D anatomy of eyes, but powerful tools are needed to perform fast conversions of anatomical reconstructions into functional eye models. Results: We developed a computing method named InSegtCone to automatically segment the crystalline cones in the apposition compound eyes of arthropods. Here, we describe the full auto-segmentation process, showcase its application to three different insect compound eyes and evaluate its performance. The auto-segmentation could successfully label the full individual shapes of 60-80% of the crystalline cones and is about as accurate and 250 times faster than manual labelling of the individual cones. Conclusions: We believe that InSegtCone can be an important tool for peer scientists to measure the orientation, size and dynamics of crystalline cones, leading to the accurate optical modelling of the diversity of arthropod eyes with micro-CT.
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| 4. |
- Nielsen, Otto Hojager Attermann, et al.
(författare)
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Spectral characterisation of dairy products using photon time-of-flight spectroscopy
- 2013
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Ingår i: Journal of Near Infrared Spectroscopy. - : SAGE Publications. - 0967-0335 .- 1751-6552. ; 21:5, s. 375-383
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present, for the first time, the absorption and reduced scattering spectra of commercially available milk and yoghurt products, obtained using photon-time-of-flight spectroscopy. The ability of this technique to separate the contributions from absorption and scattering in the sample provides important information on the chemical composition and micro-structural properties, which are not available with the traditional techniques used in dairy production. The instrument operates in the spectral range from 500 nm to 1030 nm. The reduced scattering coefficient varies from 5 cm(-1) for milk with 0.1% fat in the near infrared range, to 60 cm(-1) for yoghurt with 3.0% fat in the green wavelength regime. The absorption is within the range of 0.05-0.5cm(-1), with only small variation in the absolute value between products. Our results show that the reduced scattering clearly distinguishes milk and yoghurt with the same fat content and can offer a reliable way of monitoring structural formation during milk fermentation.
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| 5. |
- Salinas, Casper Bo Gravesen, et al.
(författare)
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Integrated Brain Atlas for Unbiased Mapping of Nervous System Effects Following Liraglutide Treatment
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Light Sheet Fluorescence Microscopy (LSFM) of whole organs, in particular the brain, offers a plethora of biological data imaged in 3D. This technique is however often hindered by cumbersome non-automated analysis methods. Here we describe an approach to fully automate the analysis by integrating with data from the Allen Institute of Brain Science (AIBS), to provide precise assessment of the distribution and action of peptide-based pharmaceuticals in the brain. To illustrate this approach, we examined the acute central nervous system effects of the glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide. Peripherally administered liraglutide accessed the hypothalamus and brainstem, and led to activation in several brain regions of which most were intersected by projections from neurons in the lateral parabrachial nucleus. Collectively, we provide a rapid and unbiased analytical framework for LSFM data which enables quantification and exploration based on data from AIBS to support basic and translational discovery.
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