Showing papers in "Scanning in 2011"
TL;DR: The development of the 3D version of CASINO is presented, which has an improved energy range for scanning electron microscopy and scanning transmission electron microscopeopy applications and is available freely to the scientific community.
Abstract: Monte Carlo softwares are widely used to understand the capabilities of electron microscopes. To study more realistic applications with complex samples, 3D Monte Carlo softwares are needed. In this article, the development of the 3D version of CASINO is presented. The software feature a graphical user interface, an efficient (in relation to simulation time and memory use) 3D simulation model, accurate physic models for electron microscopy applications, and it is available freely to the scientific community at this website: www.gel.usherbrooke.ca/casino/index.html. It can be used to model backscattered, secondary, and transmitted electron signals as well as absorbed energy. The software features like scan points and shot noise allow the simulation and study of realistic experimental conditions. This software has an improved energy range for scanning electron microscopy and scanning transmission electron microscopy applications.
287 citations
TL;DR: Previous studies using metrological methods in stone tool research are provided and the use of laser scanning confocal microscopy to conduct areal surface analysis using three-dimensional data sets are details.
Abstract: Early prehistoric research aims to discover the activities of our ancestors and piece together the process of evolution and sociocultural development. A key element in this process is the study of stone tools, particularly how these tools functioned in prehistory. Currently, there are no established quantitative methods that address stone tool function. This article provides a summary of previous studies using metrological methods in stone tool research and details the use of laser scanning confocal microscopy to conduct areal surface analysis using three-dimensional data sets. Research to-date is preliminary but promising and shows that microscopic metrological approaches can provide a quantitative method to identify how stone tools were used. A limited comparison of two metrological systems is presented, the results of which highlight a need for caution and further investigation on the comparability of related data sets. SCANNING 33: 294–303, 2011. © 2011 Wiley Periodicals, Inc.
62 citations
TL;DR: Molding methods used to replicate fragile prehistoric bones and teeth, where image quality was adversely affected by specimen translucency and reflectivity are described.
Abstract: Summary: Cut-marks on fossil bones and teeth are an important source of evidence in the reconstruction of ancient butchery practices. The analysis of butchery marks has allowed archaeologists to interpret aspects of past subsistence strategies and the behavior of early humans. Recent advances in optical scanning microscopy allow detailed measurements of cut-mark morphology to be undertaken. An example of this technology is the Alicona 3D InfiniteFocus imaging microscope, which has been applied recently to the study of surface modifications on bones and teeth. Three-dimensional models generated by the Alicona microscope have been used to identify cross-sectional features of experimental cut-marks that are characteristic for specific cutting actions (e.g., slicing, chopping, scraping) and different tool types (e.g., metal versus stone tools). More recently, this technology has been applied successfully to the analysis of 500,000 year-old cut-marked animal bones from Boxgrove (U.K.), as well as cannibalized 14,700 cal BP year-old human bones from Gough’s Cave (U.K.). This article describes molding methods used to replicate fragile prehistoric bones and teeth, where image quality was adversely affected by specimen translucency and reflectivity. Alicona images generated from molds and casts are often of better quality than those of the original specimen. SCANNING 33: 316–324, 2011. r 2011 Wiley Periodicals, Inc.
57 citations
TL;DR: SE images obtained by tailored mechanical design and energy-filtering will provide SE images with probe-sized resolution and dominated by surface detail currently only seen in low-voltage SEM, potentially even from thermionic-sourced columns.
Abstract: The secondary electron (SE) imaging of several samples across a range of scanning electron microscopes (SEM) and SE detectors under matched operating conditions has generated a highly variable image data set. Using microanalytical conditions (10-15 kV), images from in-column SE detectors reveal the presence of surface films and contaminants that are invisible to conventional Everhart-Thornley SE detectors under the same conditions. Data from studying the effects of working distance, the image resolution derived through contrast transfer function analysis and electrostatic mirror imaging of the SE detectors in operation combine with other studies to suggest that the classically defined SE1 component can be separated from other SE components. SE images obtained by tailored mechanical design and energy-filtering will provide SE images with probe-sized resolution and dominated by surface detail currently only seen in low-voltage SEM, potentially even from thermionic-sourced columns.
55 citations
TL;DR: This pilot study tests the reliability of laser scanning confocal microscopy to quantitatively measure wear on experimental obsidian tools to study wear on stone flakes made from an amorphous silicate like obsidian.
Abstract: This pilot study tests the reliability of laser scanning confocal microscopy (LSCM) to quantitatively measure wear on experimental obsidian tools. To our knowledge, this is the first use of confocal microscopy to study wear on stone flakes made from an amorphous silicate like obsidian. Three-dimensional surface roughness or texture area scans on three obsidian flakes used on different contact materials (hide, shell, wood) were documented using the LSCM to determine whether the worn surfaces could be discriminated using area-scale analysis, specifically relative area (RelA). When coupled with the F-test, this scale-sensitive fractal analysis could not only discriminate the used from unused surfaces on individual tools, but was also capable of discriminating the wear histories of tools used on different contact materials. Results indicate that such discriminations occur at different scales. Confidence levels for the discriminations at different scales were established using the F-test (mean square ratios or MSRs). In instances where discrimination of surface roughness or texture was not possible above the established confidence level based on MSRs, photomicrographs and RelA assisted in hypothesizing why this was so.
52 citations
TL;DR: This article experimentally investigates the spreading of droplets deposited onto rough surfaces and finds that for all tested materials, fluid spreading shows increasing tendency when mean slope of the roughness motifs (K(r) ) increases.
Abstract: Dynamics of contact line motion and wettability is essential in many industrial applications such as liquid coating, lubrication, printing, painting, condensation, etc. However, the wettability of surfaces depends not only on liquid–solid chemical properties but also can be strongly affected by surface roughness. As a practical application of controlled wettability, we can mention the self-cleaning surfaces, protective clothing, microfluidics devices, electro wetting, etc. In this article, we experimentally investigate the spreading of droplets deposited onto rough surfaces. Anisotropic surfaces were prepared by abrasive polishing on the following materials: aluminium alloy AA7064, titanium alloy Ti-6Al-4V, steel AISI 8630, copper alloy UNS C17000, machinable glass ceramic, and poly-methylmethacrylate. Topographical 2D parameters were calculated according to the following standards, defining Geometrical Product Specifications (GPS): ISO 4287, ISO 12085, ISO 13565, ISO 12780, and ISO 12181. The influence of topographical parameters on wettability and spreading phenomenon has been evaluated by statistical covariance analysis. The following parameters have strong influence on fluid spreading on rough surfaces: Rmr is the relative material ratio of the roughness profile, Trc is the microgeometric material ratio, Pmr is the relative material ratio of the raw profile, Kr is the mean slope of the roughness motifs, RONt is the peak to valley roundness deviation, and Psk is the Skewness of the raw profile. The physical meaning of selected parameters is discussed, and Kr (the mean slope of the roughness motifs) is selected as the most important and physically meaningful parameter. It has been found that for all tested materials, fluid spreading shows increasing tendency when mean slope of the roughness motifs (Kr) increases. SCANNING 33: 1–8, 2011. © 2011 Wiley Periodicals, Inc.
52 citations
TL;DR: Electron Beam-Induced Current (EBIC) measurements were used to produce 2D maps for investigating the homogeneity of solar cells to ensure that the measurements were made before the materials were altered.
Abstract: Electron Beam-Induced Current (EBIC) measurements were used to produce 2D maps for investigating the homogeneity of solar cells. These maps are acquired by scanning the electron beam of a scanning electron microscope over a small area and using a programmable sample stage to move the solar cell under the scan area. The electron beam generates electron–hole pairs in the solar cell much like light does in normal solar cell operation. Solution-processed solar cells where the active layer consisted of purely inorganic or purely organic materials were measured. Since the electron beam irreversibly damages organic material, it was important to ensure that the measurements were made before the materials were altered. SCANNING 33: 1–6, 2011. © 2011 Wiley Periodicals, Inc.
50 citations
TL;DR: The research showed that theoretic surface roughness resulting from the kinematic-geometric projection of cutting edge in the workpiece is significantly different from the reality.
Abstract: The work refers to analysis of various factors affecting surface roughness after end milling of hardened steel in high-speed milling (HSM) conditions. Investigations of milling parameters (cutting speed v(c) , axial depth of cut a(p) ) and the process dynamics that influence machined surface roughness were presented, and a surface roughness model, including cutter displacements, was elaborated. The work also involved analysis of surface profile charts from the point of view of vibrations and cutting force components. The research showed that theoretic surface roughness resulting from the kinematic-geometric projection of cutting edge in the workpiece is significantly different from the reality. The dominant factor in the research was not feed per tooth f(z) (according to the theoretical model) but dynamical phenomena and feed per revolution f.
43 citations
TL;DR: The results show that multiphoton microscopic image of collagen bundles exhibits apparently different pattern in human tissues, which indicates that collagen bundles have completely different space arrangement in these tissues.
Abstract: Multiphoton microscopic imaging of collagen plays an important role in noninvasive diagnoses of human tissue. In this study, two-photon fluorescence and second-harmonic generation (SHG) imaging of collagen in human skin dermis and submucosa of colon and stomach tissues were investigated based on multiphoton microscopy (MPM). Our results show that multiphoton microscopic image of collagen bundles exhibits apparently different pattern in human tissues. The collagen bundles can simultaneously reveal its SHG and two-photon excited fluorescence images in the submucosa of colon and stomach, whereas it solely emit SHG signal in skin dermis. The intensity spectral information from tissues further demonstrated the above results. This indicates that collagen bundles have completely different space arrangement in these tissues. Our experimental results bring more detailed information of collagen for the application of MPM in human noninvasive imaging.
43 citations
TL;DR: The atomic force microscope is used to scan microwear traces on Middle Palaeolithic (Mousterian) tools from Weasel Cave, Russia to show quantitative data and small scale features of microwear polishes interpreted (using the Keeley Method) as due to contact with meat, fresh hide, dry hide, bone, wood, and hafting.
Abstract: Since durable technology emerged between 3.4 and 3.2 million years ago, stone tools served as a major material means that hominins used to survive. Determining how different lithic tools functioned is a principal question in human evolution. The main experimentally based approach to the functional study of lithic technology uses stereo and incident-light microscopy, and is known as the Keeley Method. Although this method has demonstrated success in linking the morphology of microwear traces on flint tools to the function of the tool, there is no agreed upon model of how these microwear polishes form. At the same time, the characterization of these polishes has been a largely qualitative process. Herein, we use the atomic force microscope (AFM) to scan microwear traces on Middle Palaeolithic (Mousterian) tools from Weasel Cave, Russia to show quantitative data and small scale features of microwear polishes interpreted (using the Keeley Method) as due to contact with meat, fresh hide, dry hide, bone, wood, and hafting. These results follow those of to the previous AFM study on the experimental tools, namely that the meat and dry hide polishes are the least developed polishes with smaller changes in roughness and that the bone polish and wood polishes are more highly developed polishes and exhibit larger changes in roughness. SCANNING 33: 304–315, 2011. © 2011 Wiley Periodicals, Inc.
40 citations
TL;DR: An innovative method for the multi-scale analysis of high value-added surfaces is introduced, which consists of applying a method based on a new parameterization that allows us to characterize the form, waviness and roughness defects of a surface.
Abstract: This article introduces an innovative method for the multi-scale analysis of high value-added surfaces, which consists of applying a method based on a new parameterization. This kind of surface parameterization refers to natural modes of vibration, and is therefore named modal parameterization. It allows us to characterize the form, waviness and roughness defects of a surface. This parameterization opens up new fields of analysis, such as the appearance quality of surfaces. It is thereby possible to decompose a measured surface in a vector basis, of which vectors are represented by plane natural eigenmodes sorted by frequency and complexity. Different filtering operations can then be produced, such as extracting the primary form of the surface. To analyze the perceived quality of surfaces, these investigations focus on two approaches: that appearance defects have small periodicity, and that there is a link between curvatures and the visual impact of an anomaly. This methodology is applied to two prestige lighters, whose surfaces were measured by extended field confocal microscopy. Moreover, a prospect of this work is to develop an augmented-reality-type monitoring tool for sensory experts.
TL;DR: A new, short, and quick method was developed for preparation of specimen for observing Actinomycetes of genus Streptomyces by scanning electron microscopy, and surface of intact sporing structures of StrePTomyces was observed over a range of magnifications.
Abstract: Summary: A new, short, and quick method was developed for preparation of specimen for observing Actinomycetes of genus Streptomyces by scanning electron microscopy. The cultures were directly grown on stubs and coated with a film of gold without using any fixative and dehydrating procedures. Using this simple preparation procedure, surface of intact sporing structures of Streptomyces was observed over a range of magnifications. As the preparation procedure is so simple and rapid, this procedure could be most useful for the routine examination and identification of Streptomyces. SCANNING 33: 1–4, 2011. r 2011 Wiley Periodicals, Inc.
TL;DR: This research attempts to develop a universally accepted system that generates numerical data to independently corroborate visual comparisons for tool mark evidence, proposing a methodology that objectively evaluates the association of striated tool marks with the tools that generated them.
Abstract: Summary: Over the last several decades, forensic examiners of impression evidence have come under scrutiny in the courtroom due to analysis methods that rely heavily on subjective morphological comparisons Currently, there is no universally accepted system that generates numerical data to independently corroborate visual comparisons Our research attempts to develop such a system for tool mark evidence, proposing a methodology that objectively evaluates the association of striated tool marks with the tools that generated them In our study, 58 primer shear marks on 9 mm cartridge cases, fired from four Glock model 19 pistols, were collected using high-resolution white light confocal microscopy The resulting three-dimensional surface topographies were filtered to extract all ‘‘waviness surfaces’’—the essential ‘‘line’’ information that firearm and tool mark examiners view under a microscope Extracted waviness profiles were processed with principal component analysis (PCA) for dimension reduction Support vector machines (SVM) were used to make the profile-gun associations, and conformal prediction theory (CPT) for establishing confidence levels At the 95% confidence level, CPT coupled with PCA-SVM yielded an empirical error rate of 35% Complementary, bootstrap-based computations for estimated error rates were 0%, indicating that the error rate for the algorithmic procedure is likely to remain low on larger data sets Finally, suggestions are made for practical courtroom application of CPT for assigning levels of confidence to SVM identifications of tool marks recorded with confocal microscopy SCANNING 33: 1–7, 2011 r 2011 Wiley Periodicals, Inc
TL;DR: A review of the evolution of modeling for accurate dimensional scanning electron microscopy is presented with an emphasis on developments in the Monte Carlo technique for modeling the generation of the electrons used for imaging and measurement.
Abstract: A review of the evolution of modeling for accurate dimensional scanning electron microscopy is presented with an emphasis on developments in the Monte Carlo technique for modeling the generation of the electrons used for imaging and measurement. The progress of modeling for accurate metrology is discussed through a schematic technology timeline. In addition, a discussion of a future vision for accurate SEM dimensional metrology and the requirements to achieve it are presented.
TL;DR: Results have demonstrated that bioflocculation sediment was observed to be composed of complex networks of biofilm and appeared to be of complicated physical floc structures, and the biofilm was found to embed particles and permeate the void space, representing the dominant physical bridging mechanism of the flocs.
Abstract: Sediment flocculation is a critical component for the understanding of cohesive sediment dynamics. Traditionally, the referred study has largely been devoted to forming mechanism, influencing factors and physicochemical sediment conditions of all kinds of organic-flocculation and inorganic-flocculation. However, during the last decade, the bioflocculation of sediment by biological activity has been given increasing attention. But most studies have focused on the interrelations between biological and sedimentological variables. With the assistance of a newly developed field kit and correlative microscopy (which includes environmental scanning electron microscopy and confocal laser scanning microscopy), this article begins to bridge the resolution gap between sediment particles and biological activities as well as its metabolic products biofilm, in order to better understand the role of polymeric material biofilm in floc ultrastructure and outward floc behavior of bioflocculation sediment. Results have demonstrated that bioflocculation sediment was observed to be composed of complex networks of biofilm and appeared to be of complicated physical floc structures. The biofilm was found to embed particles and permeate the void space, representing the dominant physical bridging mechanism of the flocs and contributed to the extensive surface area, architecture characteristics, and mechanical properties of bioflocculation sediment.
TL;DR: Electrostatic force microscopy is used to study different peptide self-assembled structures such as tubes and particles and it is shown that not only geometrical information can be obtained using EFM, but also information about the composition of different structures is obtained.
Abstract: In this report electrostatic force microscopy (EFM) is used to study different peptide self-assembled structures such as tubes and particles. It is shown that not only geometrical information can be obtained using EFM, but also information about the composition of different structures. In particular we use EFM to investigate the structures of diphenylalanine peptide tubes, particles, and CSGAITIG peptide particles placed on pre-fabricated SiO2 surfaces with a backgate. We show that the cavity in the peptide tubes could be due to the presence of water residues. Additionally we show that self-assembled amyloid peptides form spherical solid structures containing the same self-assembled peptide in its interior. In both cases transmission electron microscopy is used to verify these structures. Further, the limitations of the EFM technique are discussed, especially when the observed structures become small compared with the radius of the AFM tip used. Finally, an agreement between the detected signal and the structure of the hollow peptide tubes is demonstrated. SCANNING 33: 201–207, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: A novel holographic otoscope system for measuring nanodisplacements of objects subjected to dynamic excitation needed to quantify the mechanical deformation of surfaces in mechanics, acoustics, electronics, biology, and many other fields is described.
Abstract: We describe a novel holographic otoscope system for measuring nano-displacements of objects subjected to dynamic excitation. Such measurements are necessary to quantify the mechanical deformation of surfaces in mechanics, acoustics, electronics, biology and many other fields. In particular, we are interested in measuring the sound-induced motion of biological samples, such as an eardrum. Our holographic otoscope system consists of laser illumination delivery (IS), optical head (OH), and image processing computer (IP) systems. The IS delivers the object beam (OB) and the reference beam (RB) to the OH. The backscattered light coming from the object illuminated by the OB interferes with the RB at the camera sensor plane to be digitally recorded as a hologram. The hologram is processed by the IP using Fresnel numerical reconstruction algorithm, where the focal plane can be selected freely. Our holographic otoscope system is currently deployed in a clinic, and is packaged in a custom design. It is mounted in a mechatronic positioning system to increase its maneuverability degrees to be conveniently positioned in front of the object to be measured. We present representative results highlighting the versatility of our system to measure deformations of complex elastic surfaces in the wavelength scale including a copper foil membrane and postmortem tympanic membrane (TM).
TL;DR: The surface roughness of orbital implants might be associated with the rate of complications and cell adhesion, and the nonporous PMMA implant showed the lowest roughness compared with other implant biomaterials, followed by the porous aluminum oxide implant.
Abstract: This study examined the surface nanostructures of three orbital implants: nonporous poly(methyl methacrylate) (PMMA), porous aluminum oxide and porous polyethylene. The morphological characteristics of the orbital implants surfaces were observed by atomic force microscopy (AFM). The AFM topography, phase shift and deflection images of the intact implant samples were obtained. The surface of the nonporous PMMA implant showed severe scratches and debris. The surface of the aluminum oxide implant showed a porous structure with varying densities and sizes. The PMMA implant showed nodule nanostructures, 215.56 ± 52.34 nm in size, and the aluminum oxide implant showed crystal structures, 730.22 ± 341.02 nm in size. The nonporous PMMA implant showed the lowest roughness compared with other implant biomaterials, followed by the porous aluminum oxide implant. The porous polyethylene implant showed the highest roughness and severe surface irregularities. Overall, the surface roughness of orbital implants might be associated with the rate of complications and cell adhesion. SCANNING 33: 211–221, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: The orthodontic treatment with bicuspid extraction is more responsible for the changes in surface roughness than the properties of the brackets, which suggests that the ortho-elasticity of the bracket slot was determined from the force-distance curves of atomic force microscopy.
Abstract: This study examined the effects of an orthodontic treatment using a bicuspid extraction on the surface roughness and mechanical properties of stainless steel (SS) brackets adjacent to the extraction space. Four experimental groups were employed; groups 1 and 2 used the Archist® SS brackets before and after the extraction treatment, respectively, and groups 3 and 4 used the Victory® SS brackets before and after the extraction treatment, respectively. The slot surfaces of the bracket were scanned in air at a resolution of 512 × 512 pixels with a scan speed of 0.8 line/s. The visco-elasticity of the bracket slot was determined from the force–distance curves of atomic force microscopy. The orthodontic treatment with bicuspid extraction led to a significant increase (p<0.0001) in surface roughness in both groups. In particular, the Archist® SS brackets showed more changes than the Victory® SS brackets (p<0.0005). However, there was no significant difference in properties of the Victory® and Archist® brackets between before and after treatment. This suggests that the orthodontic treatment with bicuspid extraction is more responsible for the changes in surface roughness than the properties of the brackets. SCANNING 33: 25–32, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: The findings of present investigation will help in understanding the cellular changes in granulosa cells during follicular atresia and will find applications in screening of follicles for in vitro culture, in vitro fertilization and Embryo transfer technology.
Abstract: During this study, topographic changes in healthy and atretic granulosa cells have been investigated during follicular atresia in goat ovary. Under scanning electron microscopy atresia was marked by asymmetrical shrinkage and vacuolization of cytoplasm. The specific topographical alterations observed in atretic cells were loss of micro extensions, disruption of cell–cell interaction, and smooth-textured membrane with a number of uneven depressions and ruffles. Some portions of the cell membrane were marked by extensive shrinkage due to condensation of cytosol. Irregular membrane at occasions was studded with blunt microextensions. The findings of present investigation will help in understanding the cellular changes in granulosa cells during follicular atresia and will find applications in screening of follicles for in vitro culture, in vitro fertilization and Embryo transfer technology. SCANNING 33: 21–24, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: Overall, the proposed method is best as its estimations for the noise-free peak and SNR are most consistent and accurate to within a certain acceptable degree, compared with the others.
Abstract: A new and robust parameter estimation technique, named image noise cross-correlation, is proposed to predict the signal-to-noise ratio (SNR) of scanning electron microscope images. The results of SNR and variance estimation values are tested and compared with nearest neighborhood and first-order interpolation. Overall, the proposed method is best as its estimations for the noise-free peak and SNR are most consistent and accurate to within a certain acceptable degree, compared with the others. SCANNING 33: 82–93, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: It is indicated that examination of the scar margin by MPM may lead a new way to discriminate different types of scars and better understand the scarring mechanisms.
Abstract: Multiphoton microscopy (MPM) was applied to examine the marginal region at dermis of keloid compared with atrophic scar. High-resolution large-area image showed an obvious boundary at the scar margin and different morphological patterns of elastin and collagen on the two sides, further visualized by the focused three-dimensional images. Content alteration of elastin or collagen between the two sides of boundary was quantified to show significant difference between keloid and atrophic scar. Owing to the raised property of keloid with overproduced collagen on the scar side, the content alteration was positive for elastin and negative for collagen. On the contrary, the content alteration was negative for elastin and positive for collagen in the atrophic scar case due to the atrophic collagen on the scar side. It indicated that examination of the scar margin by MPM may lead a new way to discriminate different types of scars and better understand the scarring mechanisms. SCANNING 33: 195–200, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: In this article, the authors examine some of the metrics that can be used to evaluate the influence of these assumptions and parameters on FE models with rough surfaces and discuss the relative merits of each option.
Abstract: Finite element (FE) modeling of rough surfaces is becoming increasingly common. However, the quality of the assumptions being made in these models, and thus the quality of the models themselves, is often unclear. Decisions about the geometry of the surface to be modeled, including the size of the surface to be modeled, the lateral resolution of the measured surface data to be used, and the formulation of the probabilistic surface to be used, can have a significant effect on a model's behavior. Similarly, varying model parameters, including the FE mesh density, can change the results by a factor of three or more. This work examines some of the metrics that can be used to evaluate the influence of these assumptions and parameters on FE models with rough surfaces and discusses the relative merits of each option. In particular, qualitative comparison of result plots, quantitative comparison and convergence of results parameters, qualitative and quantitative comparison of distributions of result values over various model dimensions, and more sophisticated comparison techniques inspired by image and signal processing are discussed. SCANNING 33: 353–369, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: The use of a monochromator is shown to quantitatively improve the resolution of the SEM at low beam energies by limiting the chromatic aberration contribution to the electron probe size as demonstrated with calculations and images of suitable samples.
Abstract: The resolution of secondary electron low beam energy imaging of a scanning electron microscope equipped with a monochromator is quantitatively measured using the contrast transfer function (CTF) method. High-resolution images, with sub-nm resolutions, were produced using low beam energies. The use of a monochromator is shown to quantitatively improve the resolution of the SEM at low beam energies by limiting the chromatic aberration contribution to the electron probe size as demonstrated with calculations and images of suitable samples. Secondary electron image resolution at low beam energies is ultimately limited by noise in the images as shown by the CTFs. SCANNING 33: 147–154, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: This study compares results of a commercially available image cytometry program to data obtained using the open-source software CellProfiler and finds that CP is appropriate for cellular analysis on a self-assembled microscope, thereby enabling affordable cytometry.
Abstract: Summary: Image cytometry is an important technique in affordable healthcare and cellular research. Some efforts toward establishing a personal, lowcost cytometer have been described in the literature. However, a self-assembled fluorescence microscope requires software for cytometric analysis. There are some open-source image-based software analysis applications available. However, for a quantitative analysis of images, software that can generate data comparable to those of previously evaluated cytometric analyses programs is required. Hence, the aim of this study is to compare results of a commercially available image cytometry program to data obtained using the open-source software CellProfiler (CP). Leukocytes and fluorescent bead images obtained using a Laser Scanning Cytometer were analyzed by CP and the results compared with those of conventional cytometric analyses’ programs. Algorithms were developed enabling the analysis of leukocytes and beads by CP. CP provided similar results to those obtained by the cytometer software. Hallmark parameters, including cell count and fluorescence intensity, revealed a high correlation in the analysis of both programs. Therefore, CP is appropriate for cellular analysis on a self-assembled microscope, thereby enabling affordable cytometry. SCANNING 33: 1–8, 2011.r 2011 Wiley Periodicals, Inc.
TL;DR: The current design of low-voltage columns is explored, including variations on compound lenses and miniature lenses, and from a system level, the strength and weaknesses of each design are discussed.
Abstract: Low-voltage microscopy can produce high-resolution, high-contrast images of nanometer-scale surface features. Several techniques exist for low-energy electron generation, but most successful in current instrumentation is the combination of a magnetic lens with an electrostatic immersion lens. This compound lens allows the low-voltage column to maintain high potential in the column while independently controlling the landing energy on the sample. Aberration coefficients decrease linearly with the immersion ratio leading to larger optimum semiconvergent angle on the sample and improvement in spot size and beam current. Most recently highly scaled miniature electron beam columns have shown promising low-voltage performance from all electrostatic lenses operating only at low potential. This article explores the current design of low-voltage columns, including variations on compound lenses and miniature lenses, and from a system level, discusses the strength and weaknesses of each design. SCANNING 33: 155–161, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: The findings showed that multiphoton microscopy may have potential in a clinical setting as an in vivo diagnostic and monitoring system for therapy in lymphology and may allow visualization of dynamic collagen alteration during the progression of lymphedema.
Abstract: Changes of dermal collagen are characteristic for chronic lymphedema. To evaluate these changes, a real-time imaging based on two-photon excited fluorescence and second-harmonic generation was developed for investigating collagen of lymphedematous mouse and rat tail skin in vivo. Our findings showed that the technique could image the morphological changes and distribution of collagen in lymphedematous mouse and rat tail skin in vivo. More importantly, it may allow visualization of dynamic collagen alteration during the progression of lymphedema. Our findings demonstrated that multiphoton microscopy may have potential in a clinical setting as an in vivo diagnostic and monitoring system for therapy in lymphology. SCANNING 33:463–467, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: The association between the roughness and cell adhesion suggests that the nanostructure of autogenous fascia lata biomaterials is the best for frontalis sling and that of the silicone rod biomaterial's is the worst.
Abstract: This study examined the nanostructural surface of three frontalis sling biomaterials: autogenous fascia lata, preserved fascia lata and silicone rod. The morphological characteristics of the sling biomaterial surfaces were examined qualitatively and quantitatively by scanning electron microscopy and atomic force microscopy, respectively. The autogenous fascia lata showed well-arranged nanostructures of parallel fascia collagen fibrils with clear 67 nm axial periodicity, whereas the preserved fascia lata showed tangled nanostructures of damaged collagen fibril bundles. The silicone rod showed a substantial amount of debris with some scratches and the smoothest roughness compared with the other sling biomaterials, followed by preserved fascia lata. Autogenous fascia lata showed the highest surface roughness. The association between the roughness and cell adhesion suggests that the nanostructure of autogenous fascia lata biomaterials is the best for frontalis sling and that of the silicone rod biomaterials is the worst. SCANNING 33:419–425, 2011. © 2011 Wiley Periodicals, Inc.
TL;DR: An analysis of the advantages and disadvantages of wet STEM compared with standard transmission electron microscopy (TEM) and the growth of polyhydroxyalkanoate and triacylglycerol carbon storage inclusions is presented.
Abstract: Wet scanning-transmission electron microscopy (STEM) is a technique that allows high-resolution transmission imaging of biological samples in a hydrated state, with minimal sample preparation. However, it has barely been used for the study of bacterial cells. In this study, we present an analysis of the advantages and disadvantages of wet STEM compared with standard transmission electron microscopy (TEM). To investigate the potential applications of wet STEM, we studied the growth of polyhydroxyalkanoate and triacylglycerol carbon storage inclusions. These were easily visible inside cells, even in the early stages of accumulation. Although TEM produces higher resolution images, wet STEM is useful when preservation of the sample is important or when studying the relative sizes of different features, since samples do not need to be sectioned. Furthermore, under carefully selected conditions, it may be possible to maintain cell viability, enabling new types of experiments to be carried out. To our knowledge, internal features of bacterial cells have not been imaged previously by this technique.
TL;DR: It is shown that label-free second harmonic generation (SHG) imaging is feasible and effective in quantitatively differentiating the fibroadenomal tissue from normal breast tissue.
Abstract: Early detection of fibroadenoma (FA) is critical for preventing subsequent breast cancer. In this work, we show that label-free second harmonic generation (SHG) imaging is feasible and effective in quantitatively differentiating the fibroadenomal tissue from normal breast tissue. With the advent of the clinical portability of miniature SHG microscopy, we believe that the technique has great potential in offering a noninvasive in vivo imaging tool for early detection of FA and monitoring the treatment responses of FA in clinics. SCANNING 33: 208–210, 2011. © 2011 Wiley Periodicals, Inc.