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Journal of Microscopy

Y Qu, Y Hu, P Zhang
Due to the large slope and complex geometry, it is difficult to measure the three-dimensional parameters of cutting tools and drill bits by using general optical measurement method. A method that combines the multiview rotation scanning and nonmechanical focus variation by using a liquid lens is proposed in this paper. Firstly, the workpiece is rotated by using a rotation unit, and in every rotation position, a sequence of images of the workpiece are captured in the axial direction. Secondly, the relative degree of focus is measured for all pixels by using focus measure operators to obtain the depth value corresponding to each pixel...
September 7, 2018: Journal of Microscopy
G Naumann, K Lippmann, J Eilers
Two-photon microscopy (2PM) offers great potential in fluorescence imaging of intracellular Na+ dynamics of live cells. A severe drawback, however, is that quantitative ratioing of fluorescence intensities at different wavelengths [possible in one-photon imaging with the classical Na+ -indicator dye sodium-binding benzofuran isophtalate (SBFI)] is not practical in 2PM. We aimed at establishing 2PM-based time-correlated fluorescence lifetime measurements as an alternative method for quantifying Na+ dynamics...
September 7, 2018: Journal of Microscopy
E A Ingerman, R A London, R Heintzmann, M G L Gustafsson
Structured-illumination microscopy allows widefield fluorescence imaging with resolution beyond the classical diffraction limit. Its linear form extends resolution by a factor of two, and its nonlinear form by an in-principle infinite factor, the effective resolution in practice being determined by noise. In this paper, we analyse the noise properties and achievable resolution of linear and nonlinear 1D and 2D patterned SIM from a frequency-space perspective. We develop an analytical theory for a general case of linear or nonlinear fluorescent imaging, and verify the analytical calculations with numerical simulation for a special case where nonlinearity is produced by photoswitching of fluorescent labels...
August 28, 2018: Journal of Microscopy
X Wang, J Bai, T Walther
Energy-dispersive X-ray mapping in a scanning transmission electron microscope is a method to visualize the spatial distribution of chemical elements in a sample. Quantification of the signal intensities depends on proper background elimination and correction of the self-absorption and fluorescence of X-ray lines in the sample. The latter become particularly relevant for slightly thicker and rough samples, small take-off angles and low-energetic X-ray lines, for which we have recently introduced a self-consistent absorption correction based on effective k*-factors selected automatically from curves simulated as function of a K/L line intensity ratio of one of the heavier elements in the sample for ranges of different compositions...
August 21, 2018: Journal of Microscopy
S Liu, L Sun, J Gao, K Li
The focused ion beam-scanning electron microscope (FIB-SEM) system plays a crucial role in the research of shale reservoirs. It enables visualise nano-scale pores and helps characterise unconventional reservoirs. In this system, FIB removes a thin layer and SEM generates a high-resolution grey-scale image of this fresh surface. By iteratively using FIB and SEM, we can create a series of 2D images. Through stacking these images, a 3D model of a rock sample is generated. However, curtain noise of varying intensity often appears in FIB-SEM data...
August 11, 2018: Journal of Microscopy
M Fuest, G M Nocera, M M Modena, D Riedel, Y X Mejia, T P Burg
Correlating live-cell imaging with electron microscopy is among the most promising approaches to relate dynamic functions of cells or small organisms to their underlying ultrastructure. The time correlation between light and electron micrographs, however, is limited by the sample handling and fixation required for electron microscopy. Current cryofixation methods require a sample transfer step from the light microscope to a dedicated instrument for cryofixation. This transfer step introduces a time lapse of one second or more between live imaging and the fixed state, which is studied by electron microscopy...
August 8, 2018: Journal of Microscopy
Rishabh Sharma, Isaac Chelladurai, Andrew D Orme, Michael P Miles, Christophe Giraud-Carrier, David T Fullwood
Although microscopy is often treated as a quasi-static exercise for obtaining a snapshot of events and structure, it is clear that a more dynamic approach, involving real-time decision making for guiding the investigation process, may provide deeper insights, more efficiently. On the other hand, many applications of machine learning involve the interpretation of local circumstances from experience gained over many observations; that is, machine learning potentially provides an ideal solution for more efficient microscopy...
August 8, 2018: Journal of Microscopy
K Kuchler, B Prifling, D Schmidt, H Markötter, I Manke, T Bernthaler, V Knoblauch, V Schmidt
It is well known that the microstructure of electrodes in lithium-ion batteries has an immense impact on their overall performance. The compaction load during the calendering process mainly determines the resulting morphology of the electrode. Therefore, NCM-based cathode films from uncompacted (0 MPa) to most highly compacted (1000 MPa) were manufactured, which corresponds to global porosities ranging from about 50% to 18%. All samples have been imaged using synchrotron tomography. These image data allow an extensive analysis of the 3D cathode microstructure with respect to increasing compaction...
August 8, 2018: Journal of Microscopy
W Cao, T Sun, G Fardell, B Price, W Dewulf
Beam hardening artefacts deteriorate the reconstructed image quality in industrial computed tomography. The appearances of beam hardening artefacts can be cupping effects or streaks. They impair the image fidelity to the object being scanned. This work aims at comparing a variety of commonly used beam hardening correction algorithms in the context of industrial computed tomography metrology. We choose four beam hardening correction algorithms of different types for the comparison. They are a single-material linearization algorithm, a multimaterial linearization algorithm, a dual-energy algorithm and an iterative reconstruction algorithm...
August 8, 2018: Journal of Microscopy
S-T Lin, H-X Trịnh, Z-W Chen, T-H Lee
A novel differential interference contrast microscope (DICM) is proposed in this research. It is constituted by inserting a Savart shear prism between the objective and sample of a polarising microscope having a rotatable analyser as the phase-shifter, and it is with the ability to enhance image contrast using the principle of shearing interferometry. This letter is to introduce the configuration, interpret the interference patterns and present the experimental setup of the DICM. In addition, this letter is to display the experimental results from the uses of the setup; the results demonstrate the validity and ability of the DICM...
August 8, 2018: Journal of Microscopy
M Peña Fernández, A H Barber, G W Blunn, G Tozzi
A micromechanical characterization of biomaterials for bone tissue engineering is essential to understand the quality of the newly regenerated bone, enabling the improvement of tissue regeneration strategies. A combination of microcomputed tomography in conjunction with in situ mechanical testing and digital volume correlation (DVC) has become a powerful technique to investigate the internal deformation of bone structure at a range of dimensional scales. However, in order to obtain accurate three-dimensional strain measurement at tissue level, high-resolution images must be acquired, and displacement/strain measurement uncertainties evaluated...
July 26, 2018: Journal of Microscopy
Mohammed Mahamdeh, Steve Simmert, Anna Luchniak, Erik Schäffer, Jonathon Howard
When studying microtubules in vitro, label free imaging of single microtubules is necessary when the quantity of purified tubulin is too low for efficient fluorescent labelling or there is concern that labelling will disrupt function. Commonly used techniques for observing unlabelled microtubules, such as video enhanced differential interference contrast, dark-field and more recently laser-based interferometric scattering microscopy, suffer from a number of drawbacks. The contrast of differential interference contrast images depends on the orientation of the microtubules, dark-field is highly sensitive to impurities and optical misalignments...
July 25, 2018: Journal of Microscopy
A Wolff, N Klingner, W Thompson, Y Zhou, J Lin, Y Y Peng, J A M Ramshaw, Y Xiao
Ion beam induced heat damage in soft materials and biological samples is not yet well understood in Focused Ion Beam systems (FIBs). The work presented here discusses the physics behind the ion beam - sample interactions and the effects which lead to increases in sample temperature and potential heat damage. A model by which heat damage can be estimated and which allows parameters to be determined that reduce/prevent heat damage was derived from Fourier's law of heat transfer and compared to finite element simulations, numerical modelling results and experiments...
July 18, 2018: Journal of Microscopy
E Machado Charry, M Neumann, J Lahti, R Schennach, V Schmidt, K Zojer
We show that attenuation X-ray microcomputed tomography (μ-CT) offers a route to extract the three-dimensional pore space of paper reliably enough to distinguish samples of the same kind of paper. Here, we consider two sack kraft papers for cement bags with different basis weights and thicknesses. Sample areas of approximately 5 mm2 with a resolution of 1.5 μm are considered, i.e. sizes that exceed sample areas of 2 mm2 for which the pore structure was previously studied in the literature. The image segmentation is based on indicator kriging as a local method that removes ambiguities in assigning voxels as pore or as fibre...
July 9, 2018: Journal of Microscopy
M N D'Eurydice, C H Arns, J-Y Arns, R T Armstrong
This paper introduces an original application on reconstruction strategies for X-ray computed microtomography, enabling the observation of time-dependent changes that occur during multiphase flow. In general, by sparsely collecting radiographs, the reconstruction of the object is compromised. Optimizations can be achieved by combining specific characteristics of the dynamics with the acquisition. Herein, the proposed method relies on short random intervals in which no drastic changes occur in the sample to acquire as many radiographs as possible that constitute a reconstructible data set...
July 4, 2018: Journal of Microscopy
A J Cresswell-Boyes, A H Barber, D Mills, A Tatla, G R Davis
Artificial teeth have several advantages in preclinical training. The aim of this study is to three-dimensionally (3D) print accurate artificial teeth using scans from X-ray microtomography (XMT). Extracted and artificial teeth were imaged at 90 kV and 40 kV, respectively, to create detailed high contrast scans. The dataset was visualised to produce internal and external meshes subsequently exported to 3D modelling software for modification before finally sending to a slicing program for printing. After appropriate parameter setting, the printer deposited material in specific locations layer by layer, to create a 3D physical model...
June 28, 2018: Journal of Microscopy
K-C Lan, W Zhong, P A Mouche, H-M Tung, H Lee, B J Heuser, J F Stubbins
This work presents a methodology combining SEM, EDS, conventional EBSD, and transmission-EBSD to analyse a recrystallised Zircaloy-4 sheet and cold-worked stress-relieved (CWSR) Zircaloy-4 cladding in unprecedented detail. Second-phase precipitates (SPPs) in Zircaloy-4 specimens were revealed after chemical polishing using a solution containing hydrofluoric acid (HF). Pitting corrosion of Zircaloy-4 specimens was revealed after electropolishing using an electrolyte containing HClO4 . A zirconium coupon without SPPs was used to confirm the chemical response of SPPs on surface morphology...
June 26, 2018: Journal of Microscopy
R Flight, G Landini, I B Styles, R M Shelton, M R Milward, P R Cooper
Cell counting is commonly used to determine proliferation rates in cell cultures and for adherent cells it is often a 'destructive' process requiring disruption of the cell monolayer resulting in the inability to follow cell growth longitudinally. This process is time consuming and utilises significant resource. In this study a relatively inexpensive, rapid and widely applicable phase contrast microscopy-based technique has been developed that emulates the contrast changes taking place when bright field microscope images of epithelial cell cultures are defocused...
September 2018: Journal of Microscopy
Q Feng, W Meng, J Wang, Z Wang, J Zhang, Q Wang, Y Hou, Q Lu
We present an ultrahigh-vacuum (UHV)-sealed high-stability scanning tunnelling microscope (STM) that can be entirely immersed in liquid helium and readily used in a commercial Dewar or superconducting magnet. The STM head features a horizontal microscanner that can become standalone and ultrastable when the coarse approach inertial motor retracts. Low voltage is enough to operate the STM even at low temperature owing to the powerful motor. It is housed in a tubular chamber of 49 mm outer diameter, which can be pumped via a detachable valve (DV), UHV-sealed and remain sealed after the DV is removed...
September 2018: Journal of Microscopy
M Bawart, A Jesacher, S Bernet, M Ritsch-Marte
Alvarez lenses are actuated lens-pairs which allow one to tune the optical power by mechanical displacement of subelements. Here, we show that a recently realized modified Alvarez lens design which does not require mechanical actuation can be integrated into a confocal microscope. Instead of mechanically moving them, the sublenses are imaged onto each other in a 4f-configuration, where the lateral image shift leading to a change in optical power is created by a galvo-mirror. The avoidance of mechanical lens shifts leads to a large speed gain for axial (and hence also 3D) image scans compared to classical Alvarez lenses...
September 2018: Journal of Microscopy
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