scholarly journals Electron Microscopy Imaging of Zinc Soaps Nucleation in Oil Paint

2018 ◽  
Vol 24 (3) ◽  
pp. 318-322 ◽  
Author(s):  
Joen Hermans ◽  
Gillian Osmond ◽  
Annelies van Loon ◽  
Piet Iedema ◽  
Robyn Chapman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Tomography ◽  
High Sensitivity ◽  
Soft Materials ◽  
Study Phase ◽  
Sem Images ◽  
Paint Sample ◽  
Microscopy Imaging ◽  
Oil Paintings ◽  
Wide Range

AbstractUsing the recently developed techniques of electron tomography, we have explored the first stages of disfiguring formation of zinc soaps in modern oil paintings. The formation of complexes of zinc ions with fatty acids in paint layers is a major threat to the stability and appearance of many late 19th and early 20th century oil paintings. Moreover, the occurrence of zinc soaps in oil paintings leading to defects is disturbingly common, but the chemical reactions and migration mechanisms leading to large zinc soap aggregates or zones remain poorly understood. State-of-the-art scanning (SEM) and transmission (TEM) electron microscopy techniques, primarily developed for biological specimens, have enabled us to visualize the earliest stages of crystalline zinc soap growth in a reconstructed zinc white (ZnO) oil paint sample. In situ sectioning techniques and sequential imaging within the SEM allowed three-dimensional tomographic reconstruction of sample morphology. Improvements in the detection and discrimination of backscattered electrons enabled us to identify local precipitation processes with small atomic number contrast. The SEM images were correlated to low-dose and high-sensitivity TEM images, with high-resolution tomography providing unprecedented insight into the structure of nucleating zinc soaps at the molecular level. The correlative approach applied here to study phase separation, and crystallization processes specific to a problem in art conservation creates possibilities for visualization of phase formation in a wide range of soft materials.

Effect of moisturized air on magnetoimpedance response of Fe-based ribbons

2020 ◽  
Vol 34 (24) ◽  
pp. 2050249
Author(s):  
L. Yoosefi ◽  
V. Setoodeh
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Conditions ◽  
Surface Condition ◽  
High Sensitivity ◽  
Response Ratio ◽  
Sem Images ◽  
Weak Magnetic Fields ◽  
Magnetic Elements ◽  
Scanning Electron

High sensitivity and response ratio of magnetoimpedance (MI) sensors have raised interest for using them in different environments for detection of weak magnetic fields of magnetic elements even though the high dependence of the MI response to the surface condition of the MI sensor has limited its application in some environments. In this study, we investigate the effects originating from the MI measurement in moisturized air. Using scanning electron microscopy (SEM) images, it is observed that the surface of an Fe-based MI sensor has become rough and granular after the presence of moisture on its surface. Results can be useful for developing MI sensors for use in different environmental conditions.

Optimizing cellulose fibrillation for the production of cellulose nanofibrils by a disk grinder

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 993-1000 ◽  
Author(s):  
Chuanshuang Hu ◽  
Yu Zhao ◽  
Kecheng Li ◽  
J.Y. Zhu ◽  
Roland Gleisner
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Consumption ◽  
Cellulose Nanofibrils ◽  
Solid Loading ◽  
Cumulative Energy ◽  
Microscopy Imaging ◽  
Rotating Speed ◽  
Wide Range ◽  
Scanning Electron

Abstract The fibrillation of a bleached kraft eucalyptus pulp was investigated by means of a laboratory-scale disk grinder for the production of cellulose nanofibrils (CNF), while the parameters disk rotating speed, solid loading, and fibrillation duration were varied. The cumulative energy consumption was monitored during fibrillation. The degree of polymerization (DP) and water retention value (WRV) of the resultant cellulose fibrils were determined as measures of the degree of fibrillation, which was also visualized by scanning electron microscopy, field emission-scanning electron microscopy, and transmission electron microscopy imaging. A higher rotating speed than 1500 rpm did not improve the fibrillation judged by DP and WRV measurements. Solid loading has an insignificant effect on fibrillation in a wide range. The energy consumption (E) was determined as a function of the DP and WRV. The optimal grinding conditions were between 1200 and 1500 rpm at 2.0%–2.2% solid loading.

scholarly journals Multiscale Electron Microscopy for the Study of Viral Replication Organelles

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 197
Author(s):  
Georg Wolff ◽  
Montserrat Bárcena
Keyword(s):  
Electron Microscopy ◽  
Viral Replication ◽  
Electron Tomography ◽  
Viral Rna ◽  
Human Pathogens ◽  
Wide Range ◽  
Recent Developments ◽  
Versatile Technique ◽  
Positive Strand Rna

During infection with positive-strand RNA viruses, viral RNA synthesis associates with modified intracellular membranes that form unique and captivating structures in the cytoplasm of the infected cell. These viral replication organelles (ROs) play a key role in the replicative cycle of important human pathogens like coronaviruses, enteroviruses, or flaviviruses. From their discovery to date, progress in our understanding of viral ROs has closely followed new developments in electron microscopy (EM). This review gives a chronological account of this progress and an introduction to the different EM techniques that enabled it. With an ample repertoire of imaging modalities, EM is nowadays a versatile technique that provides structural and functional information at a wide range of scales. Together with well-established approaches like electron tomography or labeling methods, we examine more recent developments, such as volume scanning electron microscopy (SEM) and in situ cryotomography, which are only beginning to be applied to the study of viral ROs. We also highlight the first cryotomography analyses of viral ROs, which have led to the discovery of macromolecular complexes that may serve as RO channels that control the export of newly-made viral RNA. These studies are key first steps towards elucidating the macromolecular complexity of viral ROs.

scholarly journals Nanoscale characterization of the biomolecular corona by cryo-electron microscopy, cryo-electron tomography, and image simulation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sara Sheibani ◽  
Kaustuv Basu ◽  
Ali Farnudi ◽  
Aliakbar Ashkarran ◽  
Muneyoshi Ichikawa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Tomography ◽  
Three Dimensional ◽  
True Nature ◽  
Cryo Electron Microscopy ◽  
Wide Range ◽  
Cryo Electron Tomography ◽  
Nanoscale Characterization ◽  
Dimensional Reconstruction

AbstractThe biological identity of nanoparticles (NPs) is established by their interactions with a wide range of biomolecules around their surfaces after exposure to biological media. Understanding the true nature of the biomolecular corona (BC) in its native state is, therefore, essential for its safe and efficient application in clinical settings. The fundamental challenge is to visualize the biomolecules within the corona and their relationship/association to the surface of the NPs. Using a synergistic application of cryo-electron microscopy, cryo-electron tomography, and three-dimensional reconstruction, we revealed the unique morphological details of the biomolecules and their distribution/association with the surface of polystyrene NPs at a nanoscale resolution. The analysis of the BC at a single NP level and its variability among NPs in the same sample, and the discovery of the presence of nonspecific biomolecules in plasma residues, enable more precise characterization of NPs, improving predictions of their safety and efficacies.

Seeing the Forest for the Trees: Selective Staining and Contrast Enhancement Methods for Biological Electron Microscopy

2001 ◽  
Vol 7 (S2) ◽  
pp. 766-767
Author(s):  
M. H. Ellisman
Keyword(s):  
Electron Microscopy ◽  
Electron Tomography ◽  
Light And Electron Microscopy ◽  
Fluorescent Compound ◽  
Selective Staining ◽  
3 Dimensional ◽  
Cellular Processes ◽  
Wide Range ◽  
Invaluable Tool ◽  
Versatile Technique

Electron tomography has proven to be an invaluable tool for studying the 3-dimensional organization of a wide range of structures, from large cellular processes down to individual macromolecular complexes. An important requirement for electron tomography of thick specimens is the need for selective staining to delineate the structure of interest from other cellular constituents. of particular usefulness in this regard is the method of fluorescence photooxidation, whereby the reactive oxygen generated by a fluorescent compound is used to oxidize diaminobenzidine into a reaction product that can then be visualized with the electron microscope. The main advantages of this method are that not only does it allow for excellent correlated light and electron microscopy, but also the relatively small size of the oxidizing agent used allows for excellent 3-D labeling with high resolution.This method has proven to be a particularly versatile technique.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Application of Imaging Plate to High-Voltage Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 168-169
Author(s):  
Seiji Isoda ◽  
Kimitsugu Saitoh ◽  
Sakumi Moriguchi ◽  
Takashi Kobayashi
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
High Sensitivity ◽  
Imaging Plate ◽  
High Quality ◽  
Electron Dose ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Recording Material

On the observation of structures by high resolution electron microscopy, recording materials with high sensitivity and high quality is awaited, especially for the study of radiation sensitive specimens. Such recording material should be easily combined with the minimum dose system and cryoprotection method. Recently a new recording material, imaging plate, comes to be widely used in X-ray radiography and also in electron microscopy, because of its high sensitivity, high quality and the easiness in handling the images with a computer. The properties of the imaging plate in 100 to 400 kV electron microscopes were already discussed and the effectiveness was revealed.It is demanded to study the applicability of the imaging plate to high voltage electron microscopy. The quality of the imaging plate was investigated using an imaging plate system (JEOL EM-HSR100) equipped in a new Kyoto 1000kV electron microscope. In the system both the imaging plate and films can be introduced together into the camera chamber. Figure 1 shows the effect of accelerating voltage on read-out signal intensities from the imaging plate. The characteristic of commercially available imaging plates is unfortunately optimized for 100 to 200 keV electrons and then for 600 to 1000 keV electrons the signal is reduced. In the electron dose range of 10−13 to 10−10 C/cm2, the signal increases linearly with logarithm of electron dose in all acceralating volatges.

Recent Progress and Plans in Computer-Controlled High Resolution Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 154-155
Author(s):  
W.J. de Ruijter ◽  
Peter Rez ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Digital Processing ◽  
High Resolution Electron Microscopy ◽  
Objective Lens ◽  
Linear Filter ◽  
Contrast Transfer Function ◽  
Image Displacement ◽  
Spatially Resolved ◽  
Wide Range ◽  
On Line

Digital computers are becoming widely recognized as standard accessories for electron microscopy. Due to instrumental innovations the emphasis in digital processing is shifting from off-line manipulation of electron micrographs to on-line image acquisition, analysis and microscope control. An on-line computer leads to better utilization of the instrument and, moreover, the flexibility of software control creates the possibility of a wide range of novel experiments, for example, based on temporal and spatially resolved acquisition of images or microdiffraction patterns. The instrumental resolution in electron microscopy is often restricted by a combination of specimen movement, radiation damage and improper microscope adjustment (where the settings of focus, objective lens stigmatism and especially beam alignment are most critical). We are investigating the possibility of proper microscope alignment based on computer induced tilt of the electron beam. Image details corresponding to specimen spacings larger than ∼20Å are produced mainly through amplitude contrast; an analysis based on geometric optics indicates that beam tilt causes a simple image displacement. Higher resolution detail is characterized by wave propagation through the optical system of the microscope and we find that beam tilt results in a dispersive image displacement, i.e. the displacement varies with spacing. This approach is valid for weak phase objects (such as amorphous thin films), where transfer is simply described by a linear filter (phase contrast transfer function) and for crystalline materials, where imaging is described in terms of dynamical scattering and non-linear imaging theory. In both cases beam tilt introduces image artefacts.

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