Magnification Range Research Articles

Electron Microscopic Characteristics of The Blood-Air Barrier Interstitium in Fibrous Cavernous Pulmonary Tuberculosis in Comparison with Chronic Nonspecifi c Lung Diseases

Aim. To describe the ultrastructural characteristics of the blood-air barrier (BAB) interstitium in fi brous cavernous pulmonary tuberculosis (FCT) in comparison with chronic nonspecifi c lung diseases (CNSLD).Materials and methods. The fragments of the pericavernal zone and lung tissue were taken for the study at the resection border from the dead or operated for CNSLD persons (n = 163), and the perifocal and boundary zone of lung tissue. 116 CNSLD patients were divided into 3 subgroups: 1) chronic lung abscess (n = 42); 2) bronchiectasis (n = 44); 3) lung cyst (n = 30). The lung fragments of 30 patients who died from pathology not associated with lung diseases (myocardial infarction, acute cerebrovascular accident) were used as a control group to compare the morphological parameters. The criteria for inclusion of patients in the study: age from 18 to 65 years, negative clinical and laboratory data on the presence of comorbid pathology (viral hepatitis B, C and HIV). For TEM, lung fragments 1×1×1 mm in size were cut out and fi xed in a 2.5% glutaraldehyde solution in phosphate buffer (pH = 7.2–7.4) and washed in 0.1 M phosphate buffer (pH = 7.4), followed by dehydration in alcohols of an ascending concentration and placing in a mixture of Epon and Araldite resins according to the scheme. Ultrathin sections were made with Reynolds staining. Viewing and photographing preparations was carried out on a PEM-100 transmission electron microscope (Ukraine) (magnifi cation range from ×1000 to ×30 000). Results. It was established that changes in BAB components in all groups had similar features in the form of severe interstitial fi brosis, the signs of endothelial cell degeneration and destruction of varying degrees of severity, as well as the heterogeneity of the endothelial and epithelial basement membranes.Conclusion. Ultrastructural changes in the BAB components of the removed lung part in patients with FCT and chronic nonspecifi c lung diseases are characterised by a polymorphism with prevailing dystrophic and destructive changes in the perifocal zone of infl ammation, and compensatory-adaptive processes on the peripheral, especially at the resection border.

FOUR-COMPONENT AFOCAL LENS SYSTEMS

Background. Parametric synthesis of zoom-afocal optical systems for zoom-lens. Algorithm for the overall calculation of the four-component zoom-afocal systems, which provides overall limitations, the desired range of variation of the angular magnification and the field of view of the zoom-lens, the permissible vignetting of the beam beams in the entire range of angular magnification. Synthesis of afocal systems for a stationary lens, the entrance pupil of which is located behind the afocal system.Objective. Development of a universal analytical algorithm suitable for computer automation for calculating the optical and overall parameters of the components of four-component zoom-afocal systems.Methods. The zoom-afocal system is represented by subtle components. A system of equations is compiled in which the distances between the components are unknown. From the equations, the values of these distances are recovered, which provide the necessary values of the angular magnification and zero optical power of the afocal system. In this case, the magnitudes of the optical powers of the components and their ratios should ensure positive values of the distances between them. Using the formulas of the angles and heights of the zero rays on the components of the system, taking into account the permissible vignetting of the beam of rays from the edge of the field of view, the required light diameters of the components are determined.Results. Analytical dependences are obtained that allow one to determine the optical powers of the components and their relative position in the entire range of the desired change in angular magnification from the initial data. It is shown that the first component has the largest light diameter when the largest value of the angular increase in a given range is achieved.Conclusions. The results obtained make it possible to carry out in an analytical form a parametric synthesis of four-component zoom-afocal systems, taking into account the requirements for their dimensions, field of view, the range of variation of the angular increase and the permissible vignetting of the beam of rays from the edge of the field of view.

TO THE QUESTION OF AN INTEGRATED RESEARCH OF BIOLOGICAL DAMAGE TO FIBROUS MATERIALS BY THE METHOD OF RASTER ELECTRON MICROSCOPY

The article considers the need for a comprehensive study of biological damage to fibrous materials by scanning electron microscopy. The main types and characteristics of fibers and fibrous materials, their types of damage, in particular, biological, and the mechanism of their formation are described. It is shown that with modern methods for studying morphological characteristics, the most effective is the method of scanning electron microscopy, which makes it possible to directly study the object in a wide range of magnifications. The use of scanning electron microscopy makes it possible to identify qualitatively new volumetric microsigns when conducting studies of fibrous materials. Biological damage agents (biofactors) are considered — microbiological (bacteria, microbes, fungi, blue-green algae), phytological (mosses, lichens, higher plants, algae), zoological (insects, birds, mammals). Attention is focused on the study of injuries caused by mold caused by moths, dogs, etc.
 Conducting a comprehensive study of various types of damage to materials of various fibrous nature allows us to obtain an information database, the possibility of differentiating chemical, mechanical, thermal and biological damage, identifying microsigns that individualize one or another object (factor) of action, influence, increasing the potential for obtaining trace information about the actual data and circumstances of the event in those cases when only by external morphological features of the diagnosis It is not possible to repair damage. The data obtained indicate the effectiveness of the chosen research area. The results of the studies are positive for creating the optimal research scheme, methods of microscopic studies of damage to materials of fibrous nature in order to solve diagnostic, identification and situational tasks of forensic examination.

Research on a diagnostic method of gear wear fault degree based on ultra‐complete independent component analysis

In this study, a diagnostic method for gear wear fault is proposed, which is based on the ultra-complete independent component analysis. The ultra-complete analysis model is constructed, and the similar source signals more than mixing signals are separated. Based on the typical features of the fault source signal, the useful component of the mixing signals can be found. As the fault source signal and similar fault source signal are similar, the magnification range of similar shapes can be estimated by using the interval estimation method. The mapping between one-way varying magnification time domain and rotary component fault degree is identified, and the fault degree judgment standard can be established. Thus, the fault degree can be determined. The method is used to deal with the state monitoring data of the gear, and the analysis results show that the diagnostic method is of practical value.

Vision-Based Sensor for Three-Dimensional Vibrational Motion Detection in Biological Cell Injection.

Intracytoplasmic sperm injection (ICSI) is an infertility treatment where a single sperm is immobilised and injected into the egg using a glass injection pipette. Minimising vibration in three orthogonal axes is essential to have precise injector motion and full control during the egg injection procedure. Vibration displacement sensing using physical sensors in ICSI operation is challenging since the sensor interfacing is not practically feasible. This study proposes a non-invasive technique to measure the three-dimensional vibrational motion of the injection pipette by a single microscope camera during egg injection. The contrast-limited adaptive histogram equalization (CHALE) method and blob analyses technique were employed to measure the vibration displacement in axial and lateral axes, while the actual dimension of the focal axis was directly measured using the Brenner gradient algorithm as a focus measurement algorithm. The proposed algorithm operates between the magnifications range of 4× to 40× with a resolution of half a pixel. Experiments using the proposed vision-based algorithm were conducted to measure and verify the vibration displacement in axial and lateral axes at various magnifications. The results were compared against manual procedures and the differences in measurements were up to 2% among all magnifications. Additionally, the effect of injection speed on lateral vibration displacement was measured experimentally and was used to determine the values for egg deformation, force fluctuation, and penetration force. It was shown that increases in injection speed significantly increases the lateral vibration displacement of the injection pipette by as much as 54%. It has been demonstrated successfully that visual sensing has played a key role in identifying the limitation of the egg injection speed created by lateral vibration displacement of the injection pipette tip.

Automatic recognition of SEM microstructure and phases of steel using LBP and random decision forest operator

In this paper, we present a computational model for recognition of steel type i.e., ferrite-pearlite and martensite-austenite grade steel by image processing of scanning electron microscopy (SEM) micrographs followed by phase identification, segmentation and quantification. For this purpose a comprehensive SEM microstructure database were produced through in-house experiments. The diversity in the database in terms of volume fraction, grain refinement and resolution in the microstructure images were achieved through annealing, normalizing and quenching treatments to four different plain carbon steel, containing 0.1, 0.22, 0.35 and 0.48 wt. %C and capturing the images at different magnification (500×, 1000×, 1500×, 2000×, 3000× and 5000×) in SEM under secondary electron (SE) mode. The image processing schedule for this work was developed employing the Gabor filtering, local binary pattern (LBP), random decision forest (RDF) and Otsu thresholding techniques for the purpose of noise reduction, statistical feature extraction, classifier design and segmentation respectively. The prediction accuracy of steel type was found to be significantly high. In case of ferrite-pearlite type steel, the predicted pearlite fractions for the steel containing 0.1, 0.22, 0.35 and 0.48 wt. %C were found to be 0.23 ± 0.02, 0.3 ± 0.03, 0.55 ± 0.03 and 0.65 ± 0.03 respectively for the investigated range of magnification (500×–5000×). Similarly, in case of martensite-austenite type steel, the predicted fractions of martensite for the steel containing 0.1, 0.22, 0.35 and 0.48 wt. %C were found to be 0.59 ± 0.02, 0.52 ± 0.01, 0.45 ± 0.01 and 0.56 ± 0.02 respectively within the magnification range of 500× to 5000×.

Generalized spot auto-focusing method with a high-definition auto-correlation function in transmission electron microscopy.

The spot auto-focusing (AF) method with a unique high-definition auto-correlation function (HD-ACF) proposed in the previous paper is improved and is now applicable to general specimens at a wide range of magnifications. According to the definition where the AF is defocused to obtain the highest resolution, the proposed method achieves the sharpest HD-ACF profile in the AF spot image. The relationship where the sharpest HD-ACF profile gives the highest resolution is theoretically explained, and practical AF examples for different specimens and magnifications are experimentally demonstrated. Specimens include a yeast cell thin section at 10-k magnification, a standard grating replica used as a ruler at 50-k, a crystal lattice of graphitized carbon at 400-k and a 60°-tilted thin section (yeast cell) at 10-k. Different procedures are prepared to actively identify the defocus position that gives the sharpest HD-ACF profile. Every AF result demonstrates the highest-resolution image.

Grain Boundary Detection and Phase Segmentation of SEM Ferrite–Pearlite Microstructure Using SLIC and Skeletonization

In this paper, we report an efficient segmentation and grain boundary detection process using modern image processing operators like simple linear iterative clustering and skeletonization. Accurate phase segmentation is the major requirement for any phase identification and quantification operations. The proposed image processing methods have been experimented on the in-house generated 48 scanning electron microscopy (SEM) microstructures obtained from plain carbon steel samples containing 0.1, 0.22, 0.35 and 0.48 wt%C and have been subjected to both annealing and normalizing treatments. The microstructures for dataset have been captured in SEM using secondary electron mode over a wide range of magnification × 500–× 5000. The experimental results significantly validate the segmentation of ferrite and pearlite regions. Also, the grain boundary detection results appear to be plausibly effective in case of ferrite–ferrite and ferrite–pearlite boundaries. However, the grain boundary detection efficiency is found to be relatively poor in case of pearlite–pearlite boundary. The overall performance of the proposed image processing technique in context of ferrite–pearlite steel SEM images shows promising results in all circumstances of compositional range, heat treatment and magnification.

A magnification-continuous calibration method for SEM-based nanorobotic manipulation systems.

Calibration for scanning electron microscope (SEM) based nanorobotic manipulation systems is important and difficult. Most current calibration methods are cumbersome because they require customized high precision calibration boards and repeated calibration procedures in different magnifications. This paper presents a convenient magnification-continuous calibration method with high precision for SEM-based nanorobotic manipulation systems. The projection matrix containing a continuous magnification factor is obtained by modifying the affine camera model. This facilitates the simplification of the parameter computing process. Movement features are used to align the moving axes of micropositioning stages and calibrate the system, which benefits for the realization of efficient automatic calibration. Three experiments are carried out, and the results demonstrate that the proposed method is effective and practical for calibrating SEM-based nanorobotic manipulation systems under a wide range of continuous magnifications. Experiments also confirm that high precision measurements can be conducted in different magnifications with only once calibration and the relative error is within 1%.

Use of cell phone type cameras to enhance focusing and magnification in optical microscopes.

Cameras with auto-focusing and zoom capability, such as those in cell phones, can simplify focusing a microscope and at the same time provide a wide range of magnification.

Variable-Magnification Optical Stimulator for Training and Validation of Spaceborne Vision-Based Navigation

This paper addresses the design, calibration, and utilization of a hardware-in-the loop optical stimulator for the training and validation of vision-based sensors and algorithms used for spaceborne navigation. This testbed overcomes deficiencies of existing approaches in literature, which mainly focus on emulating single operational zones such as inertial, far-range, or close-range relative navigation. Consequently, the behavior of vision-based sensors and algorithms operating in mixed or transitioning navigation regimes have remained poorly assessed before launch. To address these issues, this novel optical stimulator reproduces the large geometric and radiometric dynamic range of the space environment with a pair of lenses to achieve variable magnification of an organic light emitting diode monitor. This approach is shown to support vision-based sensors of both narrow and wide field of view, increase the radiometric dynamic range of the testbed, and emulate close-range scenarios when light from an object is not collimated. A calibration procedure is presented that places sources of light at the intended angular location over the magnification range in the presence of varying distortions. The calibrated testbed is then used to simulate dynamic inertial and relative navigation scenarios of operational relevance. These hardware-in-the-loop simulations allow for the training and validation of optical hardware, software, and algorithms for future distributed space systems.

A multi-mode digital holographic microscope.

We present a transmission-mode digital holographic microscope that can switch easily between three different imaging modes: inline, dark field off-axis, and bright field off-axis. Our instrument can be used: to track through time in three dimensions microscopic dielectric objects, such as motile micro-organisms; localize brightly scattering nanoparticles, which cannot be seen under conventional bright field illumination; and recover topographic information and measure the refractive index and dry mass of samples via quantitative phase recovery. Holograms are captured on a digital camera capable of high-speed video recording of up to 2000 frames per second. The inline mode of operation can be easily configurable to a large range of magnifications. We demonstrate the efficacy of the inline mode in tracking motile bacteria in three dimensions in a 160 μm × 160 μm × 100 μm volume at 45× magnification. Through the use of a novel physical mask in a conjugate Fourier plane in the imaging path, we use our microscope for high magnification, dark field off-axis holography, demonstrated by localizing 100 nm gold nanoparticles at 225× magnification up to at least 16 μm from the imaging plane. Finally, the bright field off-axis mode facilitates quantitative phase microscopy, which we employ to measure the refractive index of a standard resolution test target and to measure the dry mass of human erythrocytes.

Unconventional magnification behaviour in microsphere-assisted microscopy

Microsphere-assisted microscopy is an original sub-diffraction-limit imaging technique allowing to reach a few hundred nanometres of lateral resolution in air only by placing a microbead in a classical optical microscope. This work aims to highlight the magnification process in microsphere-assisted microscopy which behaves differently from the case in optical microscopy. As a matter of fact, the lateral magnification of an optical microscope does not change according to focus plane positions. Experiments on the super-resolution imaging technique, performed in air through soda-lime-glass microspheres and attested by simulations, demonstrate a significant increase in the magnification factor along the microsphere imaging depth, i.e. at different object-focal-plane position of the objective. Moreover, it is shown that the magnification range, as well as its slope, depend on the size of the microsphere. Additionally, the influence of the spectral width of the illumination light source on the magnification range is highlighted.

Focus on lasers, imaging, and microscopy

Focus on lasers, imaging, and microscopy

Does magnification of SEM image influence quantification of particulate matters deposited on vegetation foliage

The metrics used to quantify the particles on the leaf surface can serve as indicators for the quality of the atmospheric environment and is employed to evaluate the ecosystem services that plants can provide. Magnification of an SEM image may affect the recognition of particles in various aspects, yet little research has examined the impact. In this study, images were obtained at magnifications of 500×, 1000×, 2000×, and 5000× for a widely planted vegetation fence species in Beijing: Euonymus japonicas. Particle amount per leaf area increased as magnification increased; the percentage of the leaf area covered by particles was a relatively stable index across magnifications at around 7% except for the magnification 2000× which was around 15%; and the weight of particles per leaf area was unstable over all magnifications. The mean area of each particle decreased from 5.68 μm2 at magnification 500× to 0.20 at magnification 5000×, and shape complexity increased as magnification increased from 1.29 at magnification 500× to 1.50 at magnification 5000×. Particles with a diameter of less than 2.5 μm are more sensitive to scale than particles with a diameter greater than 2.5 μm of judged by the differences of the characteristics, diameter, area and shape index, of particles with different diameter ranges over four magnifications. Regarding the percentage characteristic, the percentage of particles with a diameter smaller than 1 μm increased as the magnification increased and accounted for 46% at magnification 500× and 96% at magnification 5000×. The percentage of particles with an area smaller than 1 μm2 also increased as the magnification increased accounting for 56% at magnification 500× and 99% at magnification 5000×. Particles with shape index between 1–1.5 accounted for most of the particles across all four magnifications of which the percentage was 0.66–0.80. Therefore, when comparing the results from different magnifications, three factors should be considered carefully: magnification, quantification index, and particle size range. The revealed relationship of the factors can facilitate the understanding of the metrics as indicators for atmospheric environments and vegetation as a sink for atmospheric particles to improve the urban environment.

Influence of a silicon impurity on growth of diamond crystals in the Mg-C system

This article reports a study of the morphology of diamond crystals grown at 7.0 GPa and 1800 °C in the Mg-C system with the addition of silicon in an amount of 0.5 wt%. Step patterns on {111} and {100} faces were studied in a wide range of magnifications using optical microscopy (DIC), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Morphological studies revealed that a reduction in the growth rate and a change in the morphological significance of the {100} and {111} faces were associated with adsorption of a mobile impurity (silicon) leading to poisoning of kinks and (or) steps. This leads to roughing of the faces and formation of macrosteps as well as 2D and 3D nucleation islands. At a silicon concentration of 1.0 wt% or more, immobile impurity particles are apparently formed on macrostep terraces, and growth inhibition occurs according to the Cabrera-Vermilyea model.

Direct Mapping of Heterogeneous Surface Coverage in DNA-Functionalized Gold Surfaces with Correlated Electron and Fluorescence Microscopy

The characterization of biofunctionalized surfaces such as alkanethiol self-assembled monolayers (SAMs) on gold modified with DNA or other biomolecules is a challenging analytical problem, and access to a routine method is desirable. Despite substantial investigation from structural and mechanistic perspectives, robust and high-throughput metrology tools for SAMs remain elusive but essential for the continued development of these devices. We demonstrate that scanning electron microscopy (SEM) can provide image contrast of the molecular interface during SAM functionalization. The high-speed, large magnification range, and ease of use make this widely available technique a powerful platform for measuring the structure and composition of SAM surfaces. This increased throughput allows for a better understanding of the nonideal spatial heterogeneity characteristic of SAMs utilized in real-world conditions. SEM image contrast is characterized through the use of fluorescently labeled DNA, which enables correlative SEM and fluorescence microscopy. This allows identification of the DNA-modified regions at resolutions that approach the size of the biomolecule. The effect of electron beam irradiation dose is explored, which leads to straightforward lithographic patterning of DNA SAMs with nanometer resolution and with control over the surface coverage of specifically adsorbed DNA.

Enamel evaluation by scanning electron microscopy after debonding brackets and removal of adhesive remnants.

BackgroundThe bonding of accessories in the dental crown during the orthodontic treatment creates microporosities, thus promoting micromechanical retention of the adhesive to the enamel structure. After debonding brackets, at the end of the active orthodontic treatment, a certain amount of adhesive remnants must be mechanically removed from the enamel. The objective of this study was to compare, by means of scanning electron microscopy, three different methods to remove the adhesive remnants after orthodontic bracket removal.Material and MethodsAn experimental analytical study was conducted on human premolar specimens, extracted within a year or less. The preparation of the enamel was carried out with the application of 35% phosphoric acid and Transbond XT Light Cure Adhesive Primer® adhesive. Edgwise Standart prescription brackets, slot .022 “(Morelli Orthodontia) were glued to the enamel using Transbond XT® bonding resin. The brackets were placed on the center of the vestibular face of the clinical crown, and a 300-gram pressure was exerted against the surface of the enamel, measured with an orthodontic dynamometer. The brackets were debonded with adhesive removing pliers, and the samples were divided into groups, according to the protocol used for adhesive remnant removal: high-speed multi-laminated drill bit, low-speed multi-laminated drill bit, and low-speed glass fiber. After removal of the adhesive remnants, the samples went through scanning electron microscopy, obtaining electro micrographs with a magnification range of 150 X, 500 X, and 2,000 X.ResultsThe tested method showed that the best effectiveness for the removal of the adhesive remnants after bracket debonding was the use of a tungsten carbide multi-laminated high speed, followed by the use of a tungsten carbide multi-laminated, low-rotation drill. The use of fiberglass drill alone has proved to be inefficient for clinical use, given the large amounts of adhesive remnants it leaves on the enamel.ConclusionsAll methods evaluated in this study proved to be inefficient for total removal of adhesive remnants from the enamel. Key words:Dental enamel, microscopy, orthodontics.

ELECTRON MICROSCOPY – AN OVERVIEW

The electron microscope (EM) is one of the most widely used instruments in research laboratories and is central based to micro-structural analysis and therefore important to any investigation related to the processing. The SEM/TEM provides information relating to topographical features, morphology, phase distribution, compositional differences, crystal structure, crystal orientation, and the presence and location of various defects. The strength of the SEM lies in its inherent versatility due to the multiple signals generated, simple image formation process, wide magnification range, and excellent depth of field. Later The SEM has more than 300 times the depth of field of the light microscope. The higher magnifications of the SEM are rivaled only by the transmission electron microscope (TEM) which requires the electrons to penetrate through the entire thickness of the sample. TEM images allow researchers to view the samples on a molecular level, making it possible to analyze structures and texture clearer and resolute which is useful in the study of crystals and metals and also has industrial applications. As a result, sample preparation of bulk materials through TEM is tedious and time-consuming compared to the ease of SEM sample preparation and may also damage the microstructure.

X-ray focusing with efficient high-NA multilayer Laue lenses

Multilayer Laue lenses are volume diffraction elements for the efficient focusing of X-rays. With a new manufacturing technique that we introduced, it is possible to fabricate lenses of sufficiently high numerical aperture (NA) to achieve focal spot sizes below 10 nm. The alternating layers of the materials that form the lens must span a broad range of thicknesses on the nanometer scale to achieve the necessary range of X-ray deflection angles required to achieve a high NA. This poses a challenge to both the accuracy of the deposition process and the control of the materials properties, which often vary with layer thickness. We introduced a new pair of materials—tungsten carbide and silicon carbide—to prepare layered structures with smooth and sharp interfaces and with no material phase transitions that hampered the manufacture of previous lenses. Using a pair of multilayer Laue lenses (MLLs) fabricated from this system, we achieved a two-dimensional focus of 8.4 × 6.8 nm2 at a photon energy of 16.3 keV with high diffraction efficiency and demonstrated scanning-based imaging of samples with a resolution well below 10 nm. The high NA also allowed projection holographic imaging with strong phase contrast over a large range of magnifications. An error analysis indicates the possibility of achieving 1 nm focusing.