Recently, transmission electron microscopy has been used in crystallinity assessments and unit cell parameter/polymorph determinations in solid drug substances [1,2]. Lumaxis™ (roxifiban) is a glycoprotein nb/ffla (GPHb/HIa) antagonist discovered recently at The DuPont Pharmaceuticals Company [3] currently undergoing clinical evaluation for the treatment of thrombotic disorders. Lumaxis™ is converted in vivo to a zwitterionic active metabolite, XV459. As reported here, we have assessed by electron microscopy and x-ray diffraction the crystallinity of XP280, the benzenesulfonate salt of XV459, and determined the unit cell parameters of SC877, the methanesulfonate salt of the methyl ester of XV459.

Crystallinity assessment. Partial or complete transformation of crystalline phases into amorphous phases can occur during production processes that may ultimately affect the activity associated with various batches of a drug [4, 5]. Whether desired or not, the amorphous content of any drug substance is thus an important issue for the pharmaceutical industry.

The uptake of insoluble, particulate matter through the digestive tract occurs in low quantities, and the pathway and amount of particle uptake is size dependent. Previous studies have shown that the uptake of nanoparticles occurs mainly through the Peyer's patch regions of the small intestine while micrometer sized particles enter the body by a process called persorption: the paracellular uptake of microparticles from the digestive tract into the body. These studies have also shown that translocation is largely dependent on particle size: smaller particles are more readily absorbed. Research on the use of microparticles for the oral delivery of drugs, vaccines, and DNA have shown that protein, polysaccharide, and DNA microparticle encapsulation can increase uptake and bioavailability of absorbed molecules. All of these studies have used particles with diameters ranging from 0.1 to 10 μm. Metallic colloidal gold particles can be synthesized in sizes much smaller than micro- and nanoparticles currently being tested for drug delivery.

Digital representation of diagnostic imagery offers mensuration, numeric data for diagnostic clue expression, objective assessment, and the option to define standards. Quantitative measurement allows the detection and documentation of very small differences and of diagnostic information that is visually not perceived. The automated extraction of such information from microscopic imagery is beginning to yield to knowledge guided image processing and the development of image understanding systems for machine vision. In a machine vision system, knowledge guidance may be provided by an expert system that controls a top to bottom scene segmentation with constant checks on local bottom-up derived segmentation results for compliance with model specifications and final scene reconstruction. Knowledge guidance is based on a knowledge file for the fully autonomous processing of scenes from a given domain. The knowledge file includes all entities representing traditional diagnostic and histologic terms and concepts: epithelium, stroma, lumen, nucleus, secretory cell, basal cell, stroma cell, chromatin, to name a few.

It has long been recognized that detecting cancers in their early, non-invasive stage is the best strategy to control malignant diseases. This has been best demonstrated by the example of cancer of the uterine cervix. Before screening for early signs of this malignancy, the prevalence of invasive cancer of the uterine cervix in the developed world was as high as 30 women per 100,000 and the mortality was 12-15 per 100,000 women per year, (all figures represent age standardized data). Since the introduction of cervical screening programs by Pap smears, the incidence of invasive cervical cancer and mortality due to this cancer has fallen dramatically. In British Columbia, for example, where population screening was introduced 50 years ago, the incidence and mortality have decreased several-fold and are at present below 6 and 3 per 100,000, respectively (1,2). It is believed that these figures could be even lower by encouraging more women into the program and by improving both sensitivity and specificity of the cytology.

The demand for new methods of three-dimensional imaging of biological systems grown significantly over the past decades. Systems for volumetric analysis of macroscopic structures have been addressed through the introduction of modem CT/MRI systems; and on the cellular level, confocal microscopy has evolved into a powerful research tool for the examination of both biological tissues and manufactured goods. However, there persists a need for the visualization and analysis of types of material in the cubic millimeter size range, a class of materials which has not been adequately addressed by either radiological or optical sectioning techniques. These materials include research and clinical biological tissue samples, as well as many types of manufactured materials such as textiles and paper.

The main method currently in use for the examination of such materials is standard histopathology. Whether one is concerned with the diagnosis of a human tumor or the arrangement of cells in the leaf of a plant,

We have discovered that high-frequency ultrasound imaging, or ultrasound biomicroscopy, can be used to detect apoptosis in a number of experimental systems. We have shown that such detection with 30-40 MHz ultrasound is possible using cells in an in vitro system (AML-3 leukemia cells) made to undergo apoptosis in response to treatment with a variety of cancer killing chemotherapeutic drugs. We have shown that ultrasound biomicroscopy can also detect programmed cell death in tissues made to undergo apoptosis in response to photodynamic therapy, currently an experimental cancer treating regimen. Lastly, we have shown that this ultrasound imaging approach works in vivo, using living animals where apoptosis has been induced similarly using photodynamic therapy. Specifically, apoptotic cells and regions of apoptosis in tissues exhibit up to a 36-fold increase in ultrasound backscatter intensity permitting this type of cell death to be readily discriminated from surrounding viable tissue.

One of the common problems with current remote control systems is the quality of the digital image that reaches the remote user. The size, resolution, refresh rate, and latency all contribute to the quality of the remote users’ experience. We are working on a series of remote control and display systems that send images over dedicated and production networks to better understand the bandwidth and quality of service issues involved. The amount of bandwidth required is a function of compression, image size and frame rate. Different operations require quite different parameters. Focusing and astigmatism correction require faster frame rates but can be performed with reduced size. Imaging can stand slower frame rates but requires high resolution. The quality of service (QoS) is a measure of latency and how consistently the network delivers the required bandwidth.

“In-situ” TEM studies is currently going through resurgence for materials microcharacterization. One important aspect of these studies has always been the image recording process. Traditionally, the following analog image recording techniques have been used: i) “static” images taken by photographic films and ii) viewing the images with a TV camera and recording them onto a videotape [1]. On the other hand, with the advent of CCD cameras and its rapid evolution for digital “static” imaging in TEM [2-3], “real-time” digital imaging for “in-situ” experimentation has been in high demand. In this work, we report the utilization of a new CCD camera for both “real-time” and “static” image acquisitions. The performance of the camera is shown for heating/cooling “in-situ” TEM experiments performed on an aluminum alloy using a double tilt hot stage.

We have utilized a newly designed CCD camera that addresses imaging needs for “in-situ” applications.

Modern SSCs combine low noise with high sensitivity and provide digital images with high dynamic and excellent linearity. Since these images are immediately available in a PC, SSCs have become a non-dispensable tool for on-line image processing and software driven automated TEM tuning [1]. Many experiments performed nowadays in the area of high resolution, low dose, holographic reconstruction, and EFTEM [2] would not be possible without the digital input coming from SSCs.

Despite their excellent characteristics SSCs provide a restricted number of individual image points in respect to film. This turned out to be the most prominent disadvantage of SSCs especially for applications where highly resolved large specimen areas need to be captured. Tab. 1 shows a typical example for a biological application where an image detail of 4 nm (plasma membrane) needs to be resolved. Depending on the film material used, this resolution is matched more or less by a TEM magnification of ∼8,000x.

MacLispix, a public domain image processing system for the Macintosh, has been applied to a variety of image processing problems such as analysis of diffraction spots, uniform display of x-ray maps, determination of fractal dimension of particle outlines, and analysis of data cubes. Due to interest from the PC community, we have ported the software to Windows, renamed it Lispix', and distributed it for both platforms, along with example images, source and documentation.

Lispix reads TIFF files and raw files (no image header), both with pixel types of signed and unsigned 8, 16 and 32 bit integers, 4 and 8 byte IEEE standard floating point numbers, and 3x8 bit RGB color. Lispix has a variety of standard image processing operations, such as thresholding, edge finding (gradient), filtering, scaling, Linear Hough Transform, false coloring, RGB color overlays and particle measurement.

A complex three dimensional network structure results when blood fibrin polymerizes into branching threads. To understand the rheological behavior of fibrin clots and how this behavior is associated with network morphology, one must obtain quantitative measurements of morphometric parameters of the networks (e.g., fiber diameter, distance between branching points of fibers, and branching complexity) formed under various conditions. Over the past several years, researchers have measured the parameters manually from the 3D reconstruction of networks using stereo images generated with intermediate voltage electron microscopy. Our goal is to help automate this time consuming process as much as possible, and skeletonization is a promising tool. Skeletonization is a process of transforming an object into idealized thin lines. Although various techniques for skeleton computation have been developed, most of them require explicit boundary information of the objects being skeletonized, which is not directly available from raw images.

Position normalization is a method of manipulating data from any image source so that the effective information to noise ratio is dramatically increased. In this paper we present two very different examples of the application of position normalization used in the study of high current density superconductors. In the first example we use FESEM fractography to analyze grain boundary density and grain shape in micron-diameter filaments and then normalize the data obtained from individual grains to their positions with respect to the filament-matrix interface. In this way we extract the change of grain structure with position in apparently inhomogeneous microstructure. In the second example we analyze the backscattered electron intensity, BEI, from the cross-section of a superconductor filament with respect to its proximity to phase boundaries. In this way we extract small trends in the mean atomic number with a spatial resolution of better than 100 nm.

Many scientific questions encountered in electron microscopy require quantitative deductions from the observations. Comparisons of experimental observations with simulations are however, still relatively rare since measurements of intensity are normally difficult. In this paper we discuss the use of experimental observations of the effective extinction distances for zone axis silicon using a convergent beam STEM mode for comparison with a number of simulations. On the experimental side, the measurements were made with a STEM that provides accurate intensity measurements directly with a digital image recording system. Two theoretical schemes widely used in electron microscopy simulations, multislice simulation and Bloch-wave calculation, were employed for the simulations. In each case, both a TEM case and a STEM case were calculated for comparison.

The multislice simulations were carried out using codes available from Kirkland. For the TEM case with plane waves at normal incidence on the sample surface, the unscattered (0,0) exit beam gives the Bright Field (BF) intensity.

Al-Cu-Mg based alloys are of significant interest for aerospace and other applications, due to their low weight, mechanical strength and corrosion resistance. Their mechanical properties are based on a dispersion of S-phase precipitates, which have the composition Al2CuMg. The crystal structure of this inter-metallic phase has been studied using different diffraction techniques for more than five decades. While several models have been proposed for the structure of S-phase[l], only one of the previously proposed models were found to give a reasonable fit to our experimental data. This model, shown in Fig. 1 and given by Perlitz and Westgren (PW) [2] based on X-ray diffraction data, is orthorhombic with unit cell dimensions a = 0:4 nm, b = 0.923 nm, and c = 0.714 nm, space group Cmcm, containing 16 atoms in the ratio Al:Cu:Mg = 2:1:1.

Several HREM images of S-phase precipitates located near the edge of the foil, Fig. 2, recorded along the [100]s and [010]s directions, were digitized from film and used for analysis.

Recently out-of-focus, low angle electron diffraction and Foucault experiments have been carried out on superconducting specimens in a range of applied magnetic fields where the fluxons form a more or less regular lattice. Let us recall that in order to describe the effect on the electron beam in a transmission experiment of a fluxon in a tilted specimen, the fluxon itself has been approximated by a suitable bundle of straight flux tubes, relying on the important result that the phase shift of the flux tube can be calculated analytically even in the tilted specimen geometry. In this way, it is only necessary to convolute this phase shift with the chosen projected magnetic field distribution (in our case a London model with a phenomenological penetration depth of 50 nm) in order to obtain a fairly realistic model. Therefore, in order to interpret the main features of the experimental results,

For magnetic flux mapping in magnetic materials it is important to use a simple, reliable and quantitative method operating with resolution down to few nanometers scale. The traditional off-axes electron holography can reach, in principle, such a resolution. However, the time-consuming phase reconstruction procedure limits its applications to real-time dynamic studies of magnetic domains behavior under varied external field. A novel recently developed in-line holographic approach, based on magnetic interferograms generated by phase-coherent Foucault (PCF)-imaging, complies with most of these demands and is suitable for dynamic studies of domain structure. For instance, it was successfully applied for induction mapping of closure domains in soft Fe-films [1]. It was found, however, that the resolution of PCF-imaging was lower than that of off-axis electron holography, since it is limited by the observed fringe spacing [2].

We report that the real resolution of PCF-imaging can be improved significantly with help of a novel phase amplification method.

High-resolution electron microscopists are familiar with the concept of an “optimum defocus” for obtaining highresolution transmission electron microscope images. Scherzer recognized that it is possible to balance the phase changes imposed by the spherical aberration of the TEM objective lens by adjustments to lens defocus. Selection of this focus condition maximizes the same-phase transfer of structural information carried by electrons scattered from the specimen. The upper limit of spatial frequencies transferred with the same phase change determines the resolution of the microscope. The resolution and “optimum defocus” depend only on the electron wavelength of the microscope and the spherical aberration coefficient, CS, of its objective lens. Reduction of Cs is the major route to improved resolution.

With the advent of electron-optical systems able to generate negative spherical aberration (usually called “Cs correctors“), it has now become feasible to zero-out objective lens Cs in the high-resolution transmission electron microscope.

As a crystal gets smaller, diffraction spots stay visible for larger deviations from the Bragg condition. The upper limit of such deviations is connected to the threshold for getting lattice fringes in TEM images. This in turn allows one to quantify the probability of seeing cross lattice fringes along a certain zone axis. In this abstract we examine a simple semi-empirical model for the probability of detecting (001) zone cross-fringes of a spherical crystal of cubic lattice.

The upper limit for the deviation of crystal orientation from the exact Bragg condition, without losing cross fringes down a given zone, is expressed as the maximum half-angle θ1 between the zone and the electron beam. The solid angle σ subtended by a cone with this half-angle is proportional to the probability px that a randomly-oriented crystal will show the cross-fringes associated with that zone. A schematic, illustrating the principle used to calculate the probability of seeing cross-fringes, is given in Figure 1.

Factors that affect the visibility of lattice fringes include crystal orientation and thickness, as well as instrument response. As a crystal gets smaller, lattice fringes stay visible for larger deviations from the Bragg condition. Hence the persistence of fringes under tilt affects the abundance and range of lattice spacings (and angles) that one sees in an image of randomly-oriented crystals. A subset of the fringes in an image are “still-visible” after large (e.g. 35°) single or double axis tilts. If one is looking for “new-fringes” from the same crystal (e.g. to analyze it's 3D lattice parameters), rules for recognizing redundant fringes might also help out.

Here we examine a semi-empirical model for predicting the visibility of lattice fringes after tilt, by connecting the visibility to intersection of the corresponding crystal reciprocal-lattice spot with the illuminating Ewald sphere.

Creep mechanism determination on dental amalgams has been a subject of interest in recent research works. Most of these studies conclude that the creep behavior can be explained by the well-known expression: ɛ = A σnexp (-Q/RT). Reported values for n (potential coefficient of stress) are in the order of 3 for phase dispersed dental amalgams and 2 for conventional amalgams. It suggests a grain sliding creep mechanism for conventional amalgams and a climb dislocation mechanism for creep in phase dispersed amalgams due to interactions with the dispersed CuxSny particles typical of this kind of amalgam(l). For both cases, the creep process occurs inside the γ (Ag2Hg3) phase matrix of low melting point (310 °K) which is slightly higher than typical mouth temperatures of about 400 °K (37 °C). In this work some microestructural evidences are obtained to support the behavior described above by using High Resolution Transmission Electron Microscopy (HRTEM).