| 1. |
- Antonsson, Helena, et al.
(författare)
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Caregivers' reflections on their interactions with adult people with learning disabilities
- 2008
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 15:6, s. 484-91
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Tidskriftsartikel (refereegranskat)abstract
- People with learning disabilities and their professional carers often have difficulty interacting. The aim of this study was to illuminate carers' reflections on their interactions with adult people with learning disabilities. In a previous study, interactions between 16 carers and 11 residents with learning disabilities were recorded on video. In this study, stimulated recall interviews about the interactions were carried out with all the carers. The text was analysed using qualitative content analysis. The findings indicate that the carers reflected on both successful and unsuccessful interaction. Examples of successful interaction included understanding cues, satisfying needs, and managing challenging behaviours, and the carers reflected on the influences that successful interaction had on security, confidence, and satisfaction among the residents. Examples of unsuccessful interaction included failing to understand cues, failing to satisfy needs and failing to manage challenging behaviours, and the carers reflected on the consequences of such interaction, which included irritation, aggression and violence among the residents. Our findings have implications for interventions aimed at strengthening the competence of carers and developing strategies for managing challenging behaviour, in order to ensure high-quality care and a good working climate. © 2008 The Authors.
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| 2. |
- Degerman, Johan, 1976, et al.
(författare)
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An automatic system for in vitro cell migration studies
- 2009
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 233:1, s. 178-191
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a system for in vitro cell migration analysis. Adult neural stem/progenitor cells are studied using time-lapse bright-field microscopy and thereafter stained immunohistochemically to find and distinguish undifferentiated glial progenitor cells and cells having differentiated into type-1 or type-2 astrocytes. The cells are automatically segmented and tracked through the time-lapse sequence. An extension to the Chan-Vese Level Set segmentation algorithm, including two new terms for specialized growing and pruning, made it possible to resolve clustered cells, and reduced the tracking error by 65%. We used a custom-built manual correction module to form a ground truth used as a reference for tracked cells that could be identified from the fluorescence staining. On average, the tracks were correct 95% of the time, using our new segmentation. The tracking, or association of segmented cells, was performed using a 2-state Hidden Markov Model describing the random behaviour of the cells. By re-estimating the motion model to conform with the segmented data we managed to reduce the number of tracking parameters to essentially only one. Upon characterization of the cell migration by the HMM state occupation function, it was found that glial progenitor cells were moving randomly 2/3 of the time, while the type-2 astrocytes showed a directed movement 2/3 of the time. This finding indicates possibilities for cell-type specific identification and cell sorting of live cells based on specific movement patterns in individual cell populations, which would have valuable applications in neurobiological research.
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| 3. |
- Gustafsson, Anders
(författare)
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Cathodoluminescence studies of nanostructured semiconductors
- 2006
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 224:1, s. 72-78
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Tidskriftsartikel (refereegranskat)abstract
- Spatially and spectrally resolved cathodoluminescence in the scanning electron microscope is a very powerful technique for studying the optical properties of semiconductor structures, especially low-dimensional structures (structures with nanometre-sized features). The technique is generally nondestructive and can be combined with the normal imaging capabilities and analysis possibilities of the scanning electron microscope. This article gives an introduction to the technique and a number of examples of the possibilities of the technique.
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| 4. |
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| 5. |
- Jonasson, Jenny, 1976, et al.
(författare)
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A pixel-based likelihood framework for analysis of fluorescence recovery after photobleaching data
- 2008
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 232:2, s. 260-269
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Tidskriftsartikel (refereegranskat)abstract
- A new framework for the estimation of diffusion coefficients from data on fluorescence recovery after photobleaching (FRAP) with confocal laser scanning microscopy (CLSM) is presented. It is a pixel-based statistical methodology that efficiently utilizes all information about the diffusion process in the available set of images. The likelihood function for a series of images is maximized which gives both an estimate of the diffusion coefficient and a corresponding error. This framework opens up possibilities (1) to obtain localized diffusion coefficient estimates in both homogeneous and heterogeneous materials, (2) to account for time differences between the registrations at the pixels within each image, and (3) to plan experiments optimized with respect to the number of replications, the number of bleached regions for each replicate, pixel size, the number of pixels, the number of images in each series etc. To demonstrate the use of the new framework, we have applied it to a simple system with polyethylene glycol (PEG) and water where we find good agreement with diffusion coefficient estimates from NMR diffusometry. In this experiment, it is also shown that the effect of the point spread function is negligible, and we find fluorochrome-concentration levels that give a linear response function for the fluorescence intensity. © 2008 The Authors.
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| 6. |
- Jonasson, Jenny, 1976, et al.
(författare)
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Pixel-based analysis of FRAP data with a general initial bleaching profile
- 2010
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 239:2, s. 142-153
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Tidskriftsartikel (refereegranskat)abstract
- Jonasson et al. (2008), we presented a new pixel-based maximum likelihood framework for the estimation of diffusion coefficients from data on fluorescence recovery after photobleaching (FRAP) with confocal laser scanning microscopy (CLSM). The main method there, called the Gaussian profile method below, is based on the assumption that the initial intensity profile after photobleaching is approximately Gaussian. In the present paper, we introduce a method, called the Monotone profile method, where the maximum likelihood framework is extended to a general initial bleaching profile only assuming that the profile is a non-decreasing function of the distance to the bleaching centre. The statistical distribution of the image noise is further assumed to be Poisson instead of normal, which should be a more realistic description of the noise in the detector. The new Monotone profile method and the Gaussian profile method are applied to FRAP data on swelling of super absorbent polymers (SAP) in water with a Fluorescein probe. The initial bleaching profile is close to a step function at low degrees of swelling and close to a Gaussian profile at high degrees of swelling. The results obtained from the analysis of the FRAP data are corroborated with NMR diffusometry analysis of SAP with a polyethylene glycol probe having size similar to the Fluorescein. The comparison of the Gaussian and Monotone profile methods is also performed by use of simulated data. It is found that the new Monotone profile method is accurate for all types of initial profiles studied, but it suffers from being computationally slow. The fast Gaussian profile method is sufficiently accurate for most of the profiles studied, but underestimates the diffusion coefficient for profiles close to a step function. We also provide a diagnostic plot, which indicates whether the Gaussian profile method is acceptable or not.
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| 7. |
- Mölder, Anna, et al.
(författare)
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Non-invasive, label-free cell counting and quantitative analysis of adherent cells using digital holography
- 2008
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 232:2, s. 240-247
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Tidskriftsartikel (refereegranskat)abstract
- Manual cell counting is time consuming and requires a high degree of skill on behalf of the person performing the count. Here we use a technique that utilizes digital holography, allowing label-free and completely non-invasive cell counting directly in cell culture vessels with adherent viable cells. The images produced can provide both quantitative and qualitative phase information from a single hologram. The recently constructed microscope HolomonitorTM (Phase Holographic Imaging AB, Lund, Sweden) combines the commonly used phase contrast microscope with digital holography, the latter giving us the possibility of achieving quantitative information on cellular shape, area, confluence and optical thickness. This project aimed at determining the accuracy and repeatability of cell counting measurements using digital holography compared to the conventional manual cell counting method using a haemocytometer. The collected datawere also used to determine cell size and cellular optical thickness.Theresults showthat digital holography can be used for non-invasive automatic cell counting as precisely as conventional manual cell counting
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| 8. |
- Nygren, Håkan, 1952, et al.
(författare)
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Silver deposition on freeze-dried cells allows subcellular localization of cholesterol with imaging TOF-SIMS.
- 2004
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Ingår i: Journal of microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 215:Pt 2, s. 156-61
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Tidskriftsartikel (refereegranskat)abstract
- Imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used for characterization and subcellular localization of organic ions in leucocytes adhering to glass surfaces. The cells were fixed by freeze drying in 0.15 m ammonium formate buffer at pH 7.2-7.4. The freeze-dried cells were sputter-coated with silver, and the silver surface was analysed with imaging TOF-SIMS. TOF-SIMS spectra were recorded by scanning the primary ion beam over the analysis area and acquiring positive mass spectra of the ions leaving the surface. The relative brightness of each pixel within the analysis area reflects the signal intensity of a selected ion in that pixel. Data were collected separately at high mass resolution m/delta m > 7000 and at high lateral resolution (= 0.5 micro m). The images were analysed by principal component analysis (PCA). The glass-adhering cells showed a well defined attachment area with a diameter of up to 20 micro m, and an equally well defined cell body, containing the nucleus, with a diameter of 8-10 micro m. On the raw data images, the obtained cholesterol distributions were consistent with a higher cholesterol content of the cell membrane in the attachment area than in the cell body. Using PCA analysis, silver-cationized molecular cholesterol was found localized mainly in the attachment area of the cells. Cholesterol was also seen at higher concentration in circular spots of
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| 9. |
- Yao, Yiming, 1957, et al.
(författare)
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Cross sectional TEM investigation of Ni-catalysed carbon nanotube films grown by plasma enhanced CVD
- 2005
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 219, s. 69-75
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nickel-catalysed multiwall carbon nanotubes synthesized by plasma-enhanced chemical vapour deposition on a silicon substrate with acetylene and ammonia at 700 °C have been characterized by high-resolution and analytical transmission electron microscopy. The nucleation of the carbon nanotubes occurs as a consequence of the carburization and dusting of supported preformed nickel- and silicon-rich particles. This process yields disintegrated silicon-containing nickel particles dispersed in dome-shaped carbon islands adherent to the substrate. The particles act as catalysts for tube growth, resulting in aligned multiwall carbon nanotubes with a bamboo-like structure anchored to the dome-shaped carbon islands. The bottom part of the carbon islands contains bundles of graphene sheets orientated parallel to the substrate. The nanotubes are capped with fcc nickel particles containing dissolved silicon. Most of these particles have a conical shape orientated with a <110> direction along the tube growth axis, and with {110} and {111} planes as exposed faces.
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| 10. |
- Spiecker, E., et al.
(författare)
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Advantages of aberration correction for HRTEM investigation of complex layer compounds
- 2010
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Ingår i: Journal of Microscopy. - : Wiley: 12 months. - 0022-2720 .- 1365-2818. ; 237:3, s. 341-346
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Tidskriftsartikel (refereegranskat)abstract
- Aberration-corrected high-resolution transmission electron microscopy (HRTEM) has been applied to resolve the atomic structure of a complex layered crystal, (PbS)(1.14)NbS(2), which comprises a high density of incommensurate interfaces. The strong suppression of image delocalization and the favourable contrast transfer under negative C(s) imaging (NCSI) conditions have been exploited for obtaining HRTEM images which directly reveal the projected crystal structure and allow to study lattice imperfections, like stacking disorder and layer undulations, with atomic scale resolution. The advantages of aberration-corrected HRTEM over conventional HRTEM are demonstrated by direct comparison of experimental images and computer simulations.
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| 11. |
- Stollberg, Heide, et al.
(författare)
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A vacuum-compatible wet-specimen chamber for compact x-ray microscopy
- 2007
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 226:1, s. 71-73
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Tidskriftsartikel (refereegranskat)abstract
- Soft X-ray microscopy is a powerful tool for investigations of, for example, polymers or soils in their natural liquid environment. This requires a wet-specimen chamber. Compact X-ray microscopy allows the horizontal mounting of such samples, thereby reducing the influence of gravitational forces. We have developed a wet-specimen chamber for such compact X-ray microscope. The chamber is vacuum compatible, which reduces the exposure time. The vacuum sealing is achieved by a combination of mechanical sealing and sealing by bio-compatible glue. With the wet-specimen chamber the specimens can be kept in an aqueous environment in a vacuum of 10(-4) mbar for several hours. Imaging of lipid droplets in water demonstrates the function of the wet-specimen chamber.
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| 12. |
- Stollberg, Heide, et al.
(författare)
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Wavelet-based image restoration for compact x-ray microscopy
- 2003
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 211:2, s. 154-160
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Tidskriftsartikel (refereegranskat)abstract
- Compact water-window X-ray microscopy with short exposure times will always be limited on photons owing to sources of limited power in combination with low-efficency X-ray optics. Thus, it is important to investigate methods for improving the signal-to-noise ratio in the images. We show that a wavelet-based denoising procedure significantly improves the quality and contrast in compact X-ray microscopy images. A non-decimated, discrete wavelet transform (DWT) is applied to original, noisy images. After applying a thresholding procedure to the finest scales of the DWT, by setting to zero all wavelet coefficients of magnitude below a prescribed value, the inverse DWT to the thresholded DWT produces denoised images. It is concluded that the denoising procedure has potential to reduce the exposure time by a factor of 2 without loss of relevant image information.
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| 13. |
- Stollberg, Heide, et al.
(författare)
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Size-selective colloidal-gold localization in transmission x-ray microscopy
- 2007
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 225:1, s. 80-87
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Tidskriftsartikel (refereegranskat)abstract
- Colloidal gold is a useful marker for functional-imaging experiments in transmission X-ray microscopy. Due to the low contrast of gold particles with small diameters it is necessary to develop a powerful algorithm to localize the single gold particles. The presented image-analysis algorithm for identifying colloidal gold particles is based on the combination of a threshold with respect to the local absorption and shape discrimination, realized by fitting a Gaussian profile to the identified regions of interest. The shape discrimination provides the possibility of size-selective identification and localization of single colloidal gold particles down to a diameter of 50 nm. The image-analysis algorithm, therefore, has potential for localization studies of several proteins simultaneously and for localization of fiducial markers in X-ray tomography.
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| 14. |
- Adler, Jeremy
(författare)
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The unitary scale bar : human and machine readable
- 2008
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 230:1, s. 163-166
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Tidskriftsartikel (refereegranskat)abstract
- A format is described for a scale bar that encodes the length represented within the structure of the bar itself, thereby removing the need for any supporting text. Although the 'unitary' scale bar has a conventional appearance it is also machine readable and therefore retains information about the scale even when the file format is changed. The format is based on the metre and is suitable for all terrestrial applications.
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| 15. |
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| 16. |
- Almqvist, Nils, et al.
(författare)
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Micromechanical and structural properties of a pennate diatom investigated by atomic force microscopy
- 2001
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 202:3, s. 518-532
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms behind natural nanofabrication of highly structured silicas are increasingly being investigated. We have explored the use of a standard Nanoscope III Multimode atomic force microscope (AFM) to study the silica shell of diatoms. The delicate structures of the shell surface of the diatom Navicula pelliculosa (Breb.) Hilse were imaged and the shell's micromechanical properties were measured semi-quantitatively with a resolution down to approximately 10 nm. The technique to measure elasticity and hardness with the AFM was demonstrated to be useable even on these hard glass-like surfaces, Different experimental configurations and evaluation methods were tested, They gave a consistent result of the shell micromechanical properties, The first results showed that the diatom shell's overall hardness and elasticity was similar to that of known silicas. However, regions with different mechanical proper ties were distinguished. The elastic modulus varied from 7 to 20 GPa, from 20 to 100 GPa and from 30 to hundreds of GPa depending on the location. In general, the hardness measurements showed similar spatial differences, The hardness values ranged from 1 to 12 GPa but one specific part of the shell was even harder. Hence, certain localized regions of the shell were significantly harder or more elastic. These regions coincide with known characteristic features and mechanisms appearing at the different stages of the shell's growth. These results show that this method serves as a complementary tool in the study of silica biomineralization, and can detect eventual crystalline phases.
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| 17. |
- Andersson, Viktor, et al.
(författare)
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Morphology of organic electronic materials imaged via electron tomography
- 2012
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 247:3, s. 277-287
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Tidskriftsartikel (refereegranskat)abstract
- Several organic materials and blends have been studied with the use of electron tomography. Tomography reconstructions of active layers of organic solar cells, where various preparation techniques have been used, have been analysed and compared to device behaviour. In addition, materials with predefined structures, including contrast enhancing features, have been studied and double tilt data collection has been employed to improve reconstructions. Small changes in preparation procedures may lead to large differences in morphology and device performance, and the results also indicate a complex relation between these.
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| 18. |
- Berglund, M., et al.
(författare)
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Compact water-window transmission X-ray microscopy
- 2000
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 197, s. 268-273
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate sub-100 nm resolution water-window soft X-ray full-field transmission microscopy with a compact system. The microscope operates at lambda = 3.37 nm and is based on a 100 Hz table-top regenerative debris-free droplet-target laser-plasma X-ray source in combination with normal-incidence multilayer condenser optics for sample illumination. High-spatial-resolution imaging is performed with a 7.3% efficiency nickel zone plate and a 1024 x 1024 pixel CCD detector. Images of dry test samples are recorded with exposure times of a few minutes and show features smaller than 60 nm.
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| 19. |
- Bongini, Lorenzo, et al.
(författare)
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Resolving the geometry of biomolecules imaged by cryo electron tomography
- 2007
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 228:2, s. 174-184
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we describe two methods for computerized analysis of cryo electron tomography reconstructions of biomolecules. Both methods aim at quantifying the degree of structural flexibility of macromolecules and eventually resolving the inner dynamics through automatized protocols. The first method performs a Brownian dynamics evolution of a simplified molecular model into a fictitious force field generated by the tomograms. This procedure enables us to dock the simplified model into the experimental profiles. The second uses a fuzzy framework to delineate the subparts of the proteins and subsequently determine their interdomain relations. The two methods are discussed and their complementarities highlighted with reference to the case of the immunoglobulin antibody. Both artificial maps, constructed from immunoglobulin G entries in the Protein Data Bank and real tomograms are analyzed. Robustness issues and agreement with previously reported measurements are discussed.
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| 20. |
- Carlsson, Kjell, et al.
(författare)
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Confocal pH imaging of microscopic specimens using fluorescence lifetimes and phase fluorometry : influence of parameter choice on system performance
- 2000
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 199, s. 106-114
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the performance of confocal pH imaging when using phase fluorometry and fluorophores with pH-dependent lifetimes. In these experiments, the specimen is illuminated by a laser beam, whose intensity is sinusoidally modulated. The lifetime-dependent phase shift in the fluorescent signal is detected by a lock-in amplifier, and converted into a pH value through a calibration procedure. A theoretical investigation is made of how the different system parameters will influence the results concerning sensitivity and noise. Experiments carried out with the fluorophore SNAFL-2 support these theoretical predictions. It is found that, under realistic experimental conditions, we can expect a pH change of 0.1 units to be easily detected in an 8-bit digital image. However, the pixel-to-pixel root mean square noise is often of the order of one pH unit. This comparatively high level of noise has its origin in photon quantum noise. pH measurements on living cells show a systematic deviation from expected values. This discrepancy appears to be the result of fluorophore interaction with various cell constituents, and is the subject of further investigation.
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| 21. |
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| 22. |
- Dahlström, Christina, et al.
(författare)
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New Method for Characterizing Paper Coating Structures Using Argon Ion Beam Milling and Field Emission Scanning Electron Microscopy
- 2011
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 241:2, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a new method for characterizing microstructures of paper coating using argon ion beam milling technique and field emission scanning electron microscopy. The combination of these two techniques produces extremely high-quality images with very few artefacts, which are particularly suited for quantitative analyses of coating structures. A new evaluation method has been developed by using marker-controlled watershed segmentation technique of the secondary electron images. The high-quality secondary electron images with well-defined pores makes it possible to use this semi-automatic segmentation method. One advantage of using secondary electron images instead of backscattered electron images is being able to avoid possible overestimation of the porosity because of the signal depth. A comparison was made between the new method and the conventional method using greyscale histogram thresholding of backscattered electron images. The results showed that the conventional method overestimated the pore area by 20% and detected around 5% more pores than the new method. As examples of the application of the new method, we have investigated the distributions of coating binders, and the relationship between local coating porosity and base sheet structures. The technique revealed, for the first time with direct evidence, the long-suspected coating non-uniformity, i.e. binder migration, and the correlation between coating porosity versus base sheet mass density, in a straightforward way.
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| 23. |
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| 24. |
- Gavrilovic, Milan, 1981-, et al.
(författare)
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Quantification of colocalization and cross-talk based on spectral angles
- 2009
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Ingår i: Journal of Microscopy. - Oxford, UK : Blackwell Publishing. - 0022-2720 .- 1365-2818. ; 234:3, s. 311-324
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Tidskriftsartikel (refereegranskat)abstract
- Common methods for quantification of colocalization in fluorescence microscopy typically require cross-talk free images or images where cross-talk has been eliminated by image processing, as they are based on intensity thresholding. Quantification of colocalization includes not only calculating a global measure of the degree of colocalization within an image, but also a classification of each image pixel as showing colocalized signals or not. In this paper, we present a novel, automated method for quantification of colocalization and classification of image pixels. The method, referred to as SpecDec, is based on an algorithm for spectral decomposition of multispectral data borrowed from the field of remote sensing. Pixels are classified based on hue rather than intensity. The hue distribution is presented as a histogram created by a series of steps that compensate for the quantization noise always present in digital image data, and classification rules are thereafter based on the shape of the angle histogram. Detection of colocalized signals is thus only dependent on the hue, making it possible to classify also low-intensity objects, and decoupling image segmentation from detection of colocalization. Cross-talk will show up as shifts of the peaks of the histogram, and thus a shift of the classification rules, making the method essentially insensitive to cross-talk. The method can also be used to quantify and compensate for cross-talk, independent of the microscope hardware.
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| 25. |
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| 26. |
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| 27. |
- Immerstrand, Charlotte, 1974-, et al.
(författare)
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Organelle transport in melanophores analyzed by white light image correlation spectroscopy
- 2007
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 225:3, s. 275-282
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Tidskriftsartikel (refereegranskat)abstract
- Intracellular transport of organelles, vesicles and proteins is crucial in all eukaryotic cells, and is accomplished by motor proteins that move along cytoskeletal filaments. A widely used model of intracellular transport is Xenopus laevis melanophores. These cells help the frog to change color by redistributing melanin-containing organelles in the cytoplasm. The high contrast of the pigment organelles permits changes in distribution to be observed by ordinary light microscopy; other intracellular transport systems often require fluorescence labeling. Here we have developed white light Image Correlation Spectroscopy (ICS) to monitor aggregation and dispersion of pigment. Hitherto in ICS, images of fluorescent particles from Confocal Laser Scanning Microscopy (CLSM) have been used to calculate autocorrelation functions from which the density can be obtained. In the present study we show that ICS can be modified to enable analysis of light-microscopy images; it can be used to monitor pigment aggregation and dispersion, and distinguish between different stimuli. This new approach makes ICS applicable not only to fluorescent but also to black-and-white images from light or electron microscopy, and is thus very versatile in different studies of movement of particles on the membrane or in the cytoplasm of cells without potentially harmful fluorescence labeling and activation.
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| 28. |
- Johansson, Göran A., et al.
(författare)
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Exploring the use of soft X-ray microscopy for imaging subcellular structures of the inner ear
- 2004
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 215, s. 203-212
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Tidskriftsartikel (refereegranskat)abstract
- The soft X-ray microscope at the Lawrence Berkeley National Laboratory was developed for visualization of biological tissue. Soft X-ray microscopy provides high-resolution visualization of hydrated, non-embedded and non-sectioned cells and is thus potentially an alternative to transmission electron microscopy. Here we show for the first time soft X-ray micrographs of structures isolated from the guinea-pig inner ear. Sensory outer hair cells and supporting pillar cells are readily visualized. In the hair cells, individual stereocilia can easily be identified within the apical hair bundle. The underlying cuticular plate is, however, too densely composed or too thick to be clearly visualized, and thus appears very dark. The cytoplasmic structures protruding from the cuticular plates as well as the fibrillar material surrounding and projecting from the cell nuclei can be seen. In the pillar cells the images reveal individual microtubule bundles. Soft X-ray images of the acellular tectorial membrane and thin two-layered Reissner's membrane display a level of resolution comparable to low-power electron microscopy.
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| 29. |
- Kylberg, Gustaf, et al.
(författare)
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Segmentation of virus particle candidates in transmission electron microscopy images
- 2012
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Ingår i: Journal of Microscopy. - : Blackwell Publishing. - 0022-2720 .- 1365-2818. ; 245:2, s. 140-147
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present an automatic segmentation method that detects virus particles of various shapes in transmission electron microscopy images. The method is based on a statistical analysis of local neighbourhoods of all the pixels in the image followed by an object width discrimination and finally, for elongated objects, a border refinement step. It requires only one input parameter, the approximate width of the virus particles searched for. The proposed method is evaluated on a large number of viruses. It successfully segments viruses regardless of shape, from polyhedral to highly pleomorphic.
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| 30. |
- Mannelquist, Anders, et al.
(författare)
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Near field optical microscopy in aqueous solution : implementation and characterization of a vibrating probe
- 2002
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 205:1, s. 53-60
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Tidskriftsartikel (refereegranskat)abstract
- Near field optical microscopy (NSOM) is one of the possible solutions to circumvent the diffraction limit, but the control of the optical probe in solution has been a technical challenge for practical applications. Most recently, it has been shown that the pipette used in the scanning ion conductance microscope can be modified to form a high resolution near field optical probe. When combined with a novel distance modulation mechanism, a robust near field microscope can be constructed for operation in aqueous solution. In this paper, we present technical details of this design and a further characterization of the NSOM system for imaging in solution. Fundamental limitations of this approach in comparison to other systems are also discussed. Based on the current technology, it is concluded that better than 50 nm resolution should be achievable with this technique for fluorescence, as well as fluorescence resonance energy transfer, imaging of biological specimens.
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| 31. |
- Mouzon, Johanne, et al.
(författare)
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Cryo-SEM method for the observation of entrapped bubbles and degree of water filling in large wet powder compacts
- 2011
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 242:2, s. 189-196
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Tidskriftsartikel (refereegranskat)abstract
- There are generally two problems associated with cryogenic scanning electron microscopy (cryo-SEM) observations of large wet powder compacts. First, because water cannot be vitrified in such samples, formation of artefacts is unavoidable. Second, large frozen samples are difficult to fracture but also to machine into regular pieces which fit in standard holders, especially if made of hard materials like ceramics. In this article, we first describe a simple method for planning hard cryo-samples and a low-cost technique for cryo-fracture and transfer of large specimens. Subsequently, after applying the entire procedure to green pellets of iron ore produced by balling, we compare the influence of plunge- and unidirectional freezing on large entrapped bubbles throughout the samples as well as the degree of water filling at the outer surface of the pellets. By carefully investigating the presence of artefacts in large areas of the samples and by controlling the orientation of the sample during freezing and preparation, we demonstrate that unidirectional freezing enables the observation of large entrapped bubbles with minimum formation of artefacts, whereas plunge freezing is preferable for the characterization of the degree of water filling at the outer surface of wet powder compacts. The minimum formation of artefacts was due to the high packing density of the iron ore particles in the matrix
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| 32. |
- Myllymaki, M., et al.
(författare)
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Analysis of spatial structure of epidermal nerve entry point patterns based on replicated data
- 2012
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 247:3, s. 228-239
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Tidskriftsartikel (refereegranskat)abstract
- Epidermal nerve fiber (ENF) density and morphology are used to diagnose small fiber involvement in diabetic, HIV, chemotherapy induced, and other neuropathies. ENF density and summed length of ENFs per epidermal surface area are reduced, and ENFs may appear clustered within the epidermis in subjects with small fiber neuropathy compared to healthy subjects. Therefore, it is important to understand the spatial behaviour of ENFs in healthy and diseased subjects. This work investigates the spatial structure of ENF entry points, which are locations where the nerves enter the epidermis (the outmost living layer of the skin). The study is based on suction skin blister specimens from two body locations of 25 healthy subjects. The ENF entry points are regarded as a realization of a spatial point process and a second-order characteristic, namely Ripleys K function, is used to investigate the effect of covariates (e.g. gender) on the degree of clustering of ENF entry points. First, the effects of covariates are evaluated by means of pooled K functions for groups and, secondly, the statistical significance of the effects and individual variation are characterized by a mixed model approach. Based on our results the spatial pattern of ENFs in samples taken from calf is affected by the covariates but not in samples taken from foot.
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| 33. |
- Nisslert, R., et al.
(författare)
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Identification of the three-dimensional gel microstructure from transmission electron micrographs
- 2007
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 225:1, s. 42298-
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Tidskriftsartikel (refereegranskat)abstract
- Mass transport in gels depends crucially on local properties of the gel network. We propose a method for identifying the three-dimensional (3D) gel microstructure from statistical information in transmission electron micrographs. The gel strand network is modelled as a random graph with nodes and edges (branches). The distribution of edge length, the number of edges at nodes and the angles between edges at a node are estimated from transmission electron micrographs by image analysis methods. The 3D network is simulated by Markov chain Monte Carlo, with a probability function based on the statistical information found from the micrographs. The micrographs are projections of stained gel strands in slices, and we derive a formula for estimating the thickness of the stained gel slice based on the total projected gel strand length and the number of times that gel strands enter or exit the slice. © 2007 The Authors.
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| 34. |
- Norlén, L., et al.
(författare)
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Molecular cryo-electron tomography of vitreous tissue sections : current challenges
- 2009
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 235:3, s. 293-307
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Tidskriftsartikel (refereegranskat)abstract
- Electron tomography of vitreous tissue sections (tissue TOVIS) allows the study of the three-dimensional structure of molecular complexes in a near-native cellular context. Its usage is, however, limited by an unfortunate combination of noisy and incomplete data, by a technically demanding sample preparation procedure, and by a disposition for specimen degradation during data collection. Here we outline some major challenges as experienced from the application of TOVIS to human skin. We further consider a number of practical measures as well as theoretical approaches for its future development.
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| 35. |
- Peternell, Mark, 1974, et al.
(författare)
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A technique for recording polycrystalline structure and orientation during in situ deformation cycles of rock analogues using an automated fabric analyser
- 2011
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 242, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- Two in situ plane-strain deformation experiments on norcamphor and natural ice using synchronous recording of crystal c-axis orientations have been performed with an automated fabric analyser and a newly developed sample press and deformation stage. Without interrupting the deformation experiment, c-axis orientations are determined for each pixel in a 5 × 5 mm sample area at a spatial resolution of 5 μm/pixel. In the case of norcamphor, changes in microstructures and associated crystallographic information, at a strain rate of ∼2 × 10-5 s-1, were recorded for the first time during a complete in situ deformation-cycle experiment that consisted of an annealing, deformation and post-deformation annealing path. In the case of natural ice, slower external strain rates (∼1 × 10-6 s-1) enabled the investigation of small changes in the polycrystal aggregate's crystallography and microstructure for small amounts of strain. The technical setup and first results from the experiments are presented. © 2010 The Authors Journal of Microscopy © 2010 Royal Microscopical Society.
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| 36. |
- Poulikakos, L, et al.
(författare)
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Investigation of Porous Asphalt Microstructure using Optical and Electron Microscopy
- 2010
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 240:2, s. 145-154
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Tidskriftsartikel (refereegranskat)abstract
- P>Direct observations of porous asphalt concrete samples in their natural state using optical and electron microscopy techniques led to useful information regarding the microstructure of two mixes and indicated a relationship between microstructure and in situ performance. This paper presents evidence that suboptimal microstructure can lead to premature failure thus making a first step in defining well or suboptimal performing pavements with a bottom-up approach (microstructure). Laboratory and field compaction produce different samples in terms of the microstructure. Laboratory compaction using the gyratory method has produced more microcracks in mineral aggregates after the binder had cooled. Well-performing mixes used polymer-modified binders, had a more homogeneous void structure with fewer elongated voids and better interlocking of the aggregates. Furthermore, well-performing mixes showed better distribution of the mastic and better coverage of the aggregates with bitumen. Low vacuum scanning electron microscopy showed that styrene butadiene styrene polymer modification in binder exists in the form of discontinuous globules and not continuous networks. A reduction in the polymer phase was observed as a result of aging and in-service use.
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| 37. |
- Prikulis, J., et al.
(författare)
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Large-area Topography Analysis and Near-field Raman Spectroscopy using Bent Fibre Probes
- 2003
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 210:3, s. 269-273
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Tidskriftsartikel (refereegranskat)abstract
- We present a method for combined far-field Raman imaging, topography analysis and near-field spectroscopy. Surface-enhanced Raman spectra of Rhodamine 6G (R6G) deposited on silver nanoparticles were recorded using a bent fibre aperture-type near-field scanning optical microscope (NSOM) operated in illumination mode. Special measures were taken to enable optical normal-force detection for control of the tip–sample distance. Comparisons between far-field Raman images of R6G-covered Ag particle aggregates with topographic images recorded using atomic force microscopy (AFM) indicate saturation effects due to resonance excitation.
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| 38. |
- Rullgard, H., et al.
(författare)
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Simulation of transmission electron microscope images of biological specimens
- 2011
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 243:3, s. 234-256
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Tidskriftsartikel (refereegranskat)abstract
- We present a new approach to simulate electron cryo-microscope images of biological specimens. The framework for simulation consists of two parts; the first is a phantom generator that generates a model of a specimen suitable for simulation, the second is a transmission electron microscope simulator. The phantom generator calculates the scattering potential of an atomic structure in aqueous buffer and allows the user to define the distribution of molecules in the simulated image. The simulator includes a well defined electron-specimen interaction model based on the scalar Schrodinger equation, the contrast transfer function for optics, and a noise model that includes shot noise as well as detector noise including detector blurring. To enable optimal performance, the simulation framework also includes a calibration protocol for setting simulation parameters. To test the accuracy of the new framework for simulation, we compare simulated images to experimental images recorded of the Tobacco Mosaic Virus (TMV) in vitreous ice. The simulated and experimental images show good agreement with respect to contrast variations depending on dose and defocus. Furthermore, random fluctuations present in experimental and simulated images exhibit similar statistical properties. The simulator has been designed to provide a platform for development of new instrumentation and image processing procedures in single particle electron microscopy, two-dimensional crystallography and electron tomography with well documented protocols and an open source code into which new improvements and extensions are easily incorporated.
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| 39. |
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| 40. |
- Selig, Bettina, et al.
(författare)
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Automatic measurement of compression wood cell attributes in fluorescence microscopy images
- 2012
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 246, s. 298-308
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new automated method for analyzing compression wood fibers in fluorescence microscopy. Abnormal wood known as compression wood is present in almost every softwood tree harvested. Compression wood fibers show a different cell wall morphology and chemistry compared to normal wood fibers, and their mechanical and physical characteristics are considered detrimental for both construction wood and pulp and paper purposes. Currently there is the need for improved methodologies for characterization of lignin distribution in wood cell walls, such as from compression wood fibers, that will allow for a better understanding of fiber mechanical properties. Traditionally, analysis of fluorescence microscopy images of fiber cross-sections has been done manually, which is time consuming and subjective. Here, we present an automatic method, using digital image analysis, that detects and delineates softwood fibers in fluorescence microscopy images, dividing them into cell lumen, normal and highly lignified areas. It also quantifies the different areas, as well as measures cell wall thickness. The method is evaluated by comparing the automatic with a manual delineation. While the boundaries between the various fiber wall regions are detected using the automatic method with precision similar to inter and intra expert variability, the position of the boundary between lumen and the cell wall has a systematic shift that can be corrected. Our method allows for transverse structural characterization of compression wood fibers, which may allow for improved understanding of the micro-mechanical modeling of wood and pulp fibers.
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| 41. |
- Silly, Fabien
(författare)
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A robust method for processing scanning probe microscopy images and determining nanoobject position and dimensions
- 2009
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Ingår i: JOURNAL OF MICROSCOPY-OXFORD. - : Wiley. - 0022-2720 .- 1365-2818. ; 236:3, s. 211-218
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Tidskriftsartikel (refereegranskat)abstract
- Pandgt;Processing of scanning probe microscopy (SPM) images is essential to explore nanoscale phenomena. Image processing and pattern recognition techniques are developed to improve the accuracy and consistency of nanoobject and surface characterization. We present a robust and versatile method to process SPM images and reproducibly estimate nanoobject position and dimensions. This method is using dedicated fits based on the least-square method and the matrix operations. The corresponding algorithms have been implemented in the FabViewer portable application. We illustrate how these algorithms permit not only to correct SPM images but also to precisely determine the position and dimensions of nanocrystals and adatoms on surface. A robustness test is successfully performed using distorted SPM images.
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| 42. |
- Sintorn, Ida-Maria, 1976-, et al.
(författare)
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Gradient based intensity normalization
- 2010
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 240:3, s. 249-258
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Tidskriftsartikel (refereegranskat)abstract
- Intensity normalization is important in quantitative image analysis, especially when extracting features based on intensity. In automated microscopy, particularly in large cellular screening experiments, each image contains objects of similar type (e.g. cells) but the object density (number and size of the objects) may vary markedly from image to image. Standard intensity normalization methods, such as matching the grey-value histogram of an image to a target histogram from, i.e. a reference image, only work well if both object type and object density are similar in the images to be matched. This is typically not the case in cellular screening and many other types of images where object type varies little from image to image, but object density may vary dramatically. In this paper, we propose an improved form of intensity normalization which uses grey-value as well as gradient information. This method is very robust to differences in object density. We compare and contrast our method with standard histogram normalization across a range of image types, and show that the modified procedure performs much better when object density varies between images.
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| 43. |
- Takman, Per, et al.
(författare)
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High-resolution compact x-ray microscopy
- 2007
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 226:2, s. 175-181
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate compact full-field soft X-ray transmission microscopy with sub 60-nm resolution operating at λ= 2.48 nm. The microscope is based on a 100-Hz regenerative liquid-nitrogen-jet laser-plasma source in combination with a condenser zone plate and a micro-zone plate objective for high-resolution imaging onto a 2048 × 2048 pixel CCD detector. The sample holder is mounted in a helium atmosphere and allows imaging of both dry and wet specimens. The microscope design enables fast sample switching and the sample can be pre-aligned using a visible-light microscope. High-quality images can be acquired with exposure times of less than 5 min. We demonstrate the performance of the microscope using both dry and wet samples.
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| 44. |
- Wählby, Carolina, et al.
(författare)
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Combining intensity, edge, and shape information for 2D and 3D segmentation of cell nuclei in tissue sections
- 2004
-
Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 215:1, s. 67-76
-
Tidskriftsartikel (refereegranskat)abstract
- We present a region-based segmentation method in which seeds representing both object and background pixels are created by combining morphological filtering of both the original image and the gradient magnitude of the image. The seeds are then used as starting points for watershed segmentation of the gradient magnitude image. The fully automatic seeding is done in a generous fashion, so that at least one seed will be set in each foreground object. If more than one seed is placed in a single object, the watershed segmentation will lead to an initial over-segmentation, i.e. a boundary is created where there is no strong edge. Thus, the result of the initial segmentation is further refined by merging based on the gradient magnitude along the boundary separating neighbouring objects. This step also makes it easy to remove objects with poor contrast. As a final step, clusters of nuclei are separated, based on the shape of the cluster. The number of input parameters to the full segmentation procedure is only five. These parameters can be set manually using a test image and thereafter be used on a large number of images created under similar imaging conditions. This automated system was verified by comparison with manual counts from the same image fields. About 90% correct segmentation was achieved for two- as well as three-dimensional images.
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| 45. |
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| 46. |
- Chinga-Carrasco, Gary, et al.
(författare)
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A method for estimating the fibre length in fibre-PLA composites
- 2013
-
Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 250:1, s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- Wood pulp fibres are an important component of environmentally sound and renewable fibre-reinforced composite materials. The high aspect ratio of pulp fibres is an essential property with respect to the mechanical properties a given composite material can achieve. The length of pulp fibres is affected by composite processing operations. This thus emphasizes the importance of assessing the pulp fibre length and how this may be affected by a given process for manufacturing composites. In this work a new method for measuring the length distribution of fibres and fibre fragments has been developed. The method is based on; (i) dissolving the composites, (ii) preparing the fibres for image acquisition and (iii) image analysis of the resulting fibre structures. The image analysis part is relatively simple to implement and is based on images acquired with a desktop scanner and a new ImageJ plugin. The quantification of fibre length has demonstrated the fibre shortening effect because of an extrusion process and subsequent injection moulding. Fibres with original lengths of >1 mm where shortened to fibre fragments with length of <200 μm. The shortening seems to be affected by the number of times the fibres have passed through the extruder, the amount of chain extender and the fraction of fibres in the polymer matrix.
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| 47. |
- Das, Prabir Kumar, et al.
(författare)
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Microscale investigation of thin film surface ageing of bitumen
- 2014
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Ingår i: Journal of Microscopy. - : Wiley. - 2050-5698 .- 0022-2720 .- 1365-2818. ; 254:2, s. 95-107
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the mechanism of bitumen surface ageing, which was validated utilizing the atomic force microscopy and the differential scanning calorimetry. To validate the surface ageing, three different types of bitumen with different natural wax content were conditioned in four different modes: both ultraviolet and air, only ultraviolet, only air and without any exposure, for 15 and 30 days. From the atomic force microscopy investigation after 15 and 30 days of conditioning period, it was found that regardless the bitumen type, the percentage of microstructure on the surface reduced with the degree of exposure and time. Comparing all the four different exposures, it was observed that ultraviolet radiation caused more surface ageing than the oxidation. It was also found that the combined effect was not simply a summation or multiplication of the individual effects. The differential scanning calorimetry investigation showed that the amount of crystalline fractions in bitumen remain constant even after the systematic conditioning. Interestingly, during the cooling cycle, crystallization of wax molecules started earlier for the exposed specimens than the without exposed one. The analysis of the obtained results indicated that the ageing created a thin film upon the exposed surface, which acts as a barrier and creates difficulty for the wax induced microstructures to float up at the surface. From the differential scanning calorimetry analysis, it can be concluded that the ageing product induced impurities in the bitumen matrix, which acts as a promoter in the crystallization process.
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| 48. |
- Eriksson Barman, Sandra, 1985, et al.
(författare)
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A three-dimensional statistical model for imaged microstructures of porous polymer films
- 2018
-
Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 269:3, s. 247-258
-
Tidskriftsartikel (refereegranskat)abstract
- A thresholded Gaussian random field model is developed for the microstructure of porous materials. Defining the random field as a solution to stochastic partial differential equation allows for flexible modelling of nonstationarities in the material and facilitates computationally efficient methods for simulation and model fitting. A Markov Chain Monte Carlo algorithm is developed and used to fit the model to three-dimensional confocal laser scanning microscopy images. The methods are applied to study a porous ethylcellulose/hydroxypropylcellulose polymer blend that is used as a coating to control drug release from pharmaceutical tablets. The aim is to investigate how mass transport through the material depends on the microstructure. We derive a number of goodness-of-fit measures based on numerically calculated diffusion through the material. These are used in combination with measures that characterize the geometry of the pore structure to assess model fit. The model is found to fit stationary parts of the material well. Lay description We develop a stochastic model for the pore structure of a polymer material which is used as coatings to control drug release from pharmaceutical tablets. The pore geometries of the coatings determine how quickly the drug is released. For instance, the drug transport through a coating with many bottlenecks will be slower compared to the transport through a coating with a lower number of bottlenecks. The model will in future work be used to analyze how the rate of transport of the drug through the coating depends on the distribution of bottlenecks and other characteristics of the pore geometry. In this article we present the model. Each stochastic simulation from the model gives a different pore structure, but with similar pore geometries. This randomness in the model captures that each coating is different. We develop an efficient mathematical algorithm to fit the model to microscopy images of the material. The algorithm uses the information in the microscopy images to find the parameters of the model that make the pore geometry of the microscopy images as similar as possible to the pore geometries of stochastic simulations from the model. To determine how similar the geometries are we use measures that summarize different properties of the pore geometries. We also derive a new measure which compares the results of numerically calculated transport through the pore structures. These measures show that the stochastic simulations from the model are similar to the microscopy images, and we conclude that the model fits the data well.
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| 49. |
- Ghorbanpour, F., et al.
(författare)
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Marked point process analysis of epidermal nerve fibres
- 2021
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 283:1, s. 41-50
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Tidskriftsartikel (refereegranskat)abstract
- Epidermal nerve fibre (ENF) density and summed length of ENFs per epidermal surface area are reduced, and ENFs may appear more clustered within the epidermis in subjects suffering from diabetic neuropathy compared to healthy subjects. Therefore, it is important to understand the spatial behaviour of ENFs in healthy and neuropathy subjects. By using confocal microscopy data , we study the spatial structure of epidermal nerves by regarding the nerve tree locations as realizations of marked point processes . The termination points of the fibres of a nerve tree are used to define a reactive territory which is taken as a mark for the nerve tree location. We study the differences in the spatial pattern of ENFs between healthy subjects and subjects suffering from mild diabetic neuropathy by using Ripley's K function and the mark correlation function. In addition, we propose a marked sequential point process model for the nerve tree locations. Data are replicated point patterns, where we have several patterns from each subject and from each group.
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| 50. |
- Hesse, Bernhard, et al.
(författare)
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Accessing osteocyte lacunar geometrical properties in human jaw bone on the submicron length scale using synchrotron radiation mu CT
- 2014
-
Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 255:3, s. 158-168
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Tidskriftsartikel (refereegranskat)abstract
- The architectural properties of the osteocyte cell network provide a valuable basis for understanding the mechanisms of bone remodelling, mineral homeostasis, ageing and pathologies. Recent advances in synchrotron microtomography enable unprecedented three-dimensional imaging of both the bone lacunar network and the extracellular matrix. Here, we investigate the three-dimensional morphological properties of osteocyte lacunae in human healthy and bisphosphonate-related osteonecrotic jaw bone based on synchrotron X-ray computed tomography images, with a spatial isotropic voxel size of 300 nm. Bisphosphonate-related osteonecrosis of the jaw is a relatively new disease with increasing incidence, which remains poorly understood. A step forward in elucidating this malady is to assess whether, and how, the morphology of the osteocyte lacunar network is modified in the affected jaw tissue. We evaluate thousands of cell lacunae from five specimens of which three originate from patients diagnosed with bisphosphonate-associated osteonecrosis. In this exploratory study, we report three-dimensional quantitative results on lacunar volumes (296-502 mu m(3)), shape (approximated by an ellipsoidal shape with principal axes a > b > c, such that a = 2.2b and a = 4c) and spatial distribution (i.e., 50% of the mineralized matrix volume is located within 12 mu m to the closest lacunar boundary) at submicron resolution on such specimens. We observe that the average lacunar volumes of the bisphosphonate-related osteonecrotic jaw specimens were within the range of volumes found in the two specimens originating from healthy donors and conclude that lacunar volumes are not the key element in the course of bisphosphonate-related osteonecrotic jaw. In three out of five specimens we observe lacunar volume sizes in segmented osteons to be significantly different compared to lacunar volumes in the adjacent tissue regions. Furthermore, we quantify the number of lacunae containing small dense objects (on average 9%). In contrast to lacunar morphology we report the lacunar density (16 000-50 000 per mm(3)) to be different in jaw bone tissue compared to what has been reported in femoral sites.
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