Medium Magnification Research Articles

Eccrine squamous syringometaplasia mimicking a herpetic infection

A 69‐year‐old woman with a history of hypertension and essential tremor was diagnosed with a Burkitt‐like diffuse large‐cell lymphoma. She received chemotherapy with cyclophosphamide, vincristine and adriamycin (HyperCVAD). Ten days after starting the second cycle of chemotherapy (HyperCVAD), she presented with well‐defined, intense, erythematous macules which coalesced to form a symmetric diffuse erythema located on the upper back. Later, the lesions progressed and affected the lower back and perineal areas, extending to the groin. In a few days, a gradual diminution of the erythema was seen, with subsequent development of postinflammatory gray‐brownish hyperpigmentation. On the lower back, there were also superficial erosions. Some asymptomatic, closely grouped, gray papules, vesicles, and blisters were found in the groin, resembling the typical lesions of herpetic infection (Fig. 1). Two biopsies of the groin and one of the upper back were performed, and were processed for histopathologic and microbiologic study.Closely grouped gray papules, vesicles, and blisters on the groin mimicking a herpetic infectionimageThe histopathologic study showed epidermal hyperplasia with acanthosis and papillomatosis. In both biopsies, eccrine ducts covered by mature squamous epithelium were found in the reticular dermis (Fig. 2a−c). In the sample from the groin, an intracorneal bulla was found. Numerous normal isolated cornified cells were seen within the lumen of the bulla (Fig. 2d). An inflammatory mononuclear infiltrate was also present in a periductal and perivascular distribution. No multinucleation, ground‐glass nuclei, or peripheral margination of chromatin were found. Therefore, no morphologic evidence of herpes virus infection was present.Low (a), medium (b), and high (c) magnification showing epidermal hyperplasia and squamous syringometaplasia involving dermal eccrine ducts. (d) Medium power magnification of the intracorneal bulla (hematoxylin and eosin staining; a, ×40; b, ×100; c, ×400; d, ×100)imageCultures and serologic analyses for herpes simplex virus (HSV) 1 and 2, varicella zoster virus (VZV), and cytomegalovirus (CMV) were negative. The lesions were treated with topical corticosteroids, with a good response in a few days.

Two-dimensional dopant profiling of ultrashallow junction with off-axis electron holography: A round robin experiment

We briefly describe the basics of electron holography, the hologram formation, as well as its acquisition and reconstruction. Our test sample requires a holographic field of view in the medium magnification range of about 20–30 k×. Two of the microscopes (Philips) utilized for this Round Robin experiment feature a Lorentz lens for medium magnification whereas the third one (Hitachi) requires a special lens current setting in its free lens control mode. The phase images from electron holograms reveal potential differences caused by active dopants. The comparison between the phase images reconstructed from our test holograms taken with the different microscopes show excellent agreement.

Off -Axis Electron Holography for 2D Dopant Profiling of Ultra-Shallow Junctions

We briefly discuss how to set-up our Hitachi HF-2000 transmission electron microscope for medium magnification holography. Then we apply this technique to examine the activation of an as-doped wafer by annealing. We also present voltage profiles of the source-drain region of a CMOS transistor with 75 nm gate architecture taken from an off-the-shelf Intel PIII processor. Special attention is given to the analysis of the reconstructed holograms. [DOI: 10.1380/ejssnt.2004.119]

Contrast improvement of confocal retinal imaging by use of phase-correcting plates

We have developed a custom scanning laser ophthalmoscope that uses phase plates produced by photolithography to improve the contrast of human retinal images. We combined the scanning engine from a commercial real-time confocal microscope with custom optics to provide medium magnification imaging of the human retina (3 degrees field of view). Defocus and astigmatism were corrected with conventional trial lenses. Higher-order aberrations of the eye were corrected with a phase plate. A 633-nm laser was used for illuminating the retina. Inserting the phase plate into the optical system increased the contrast of a sample retinal vessel by 26%. Additionally, a number of small features of the retina, which were not visible with standard commercial imaging systems, became visible. There results illustrate that, with the rapid development of custom fabrication techniques for refractive corrections, improved diagnostic imaging with little added complexity to existing ophthalmic imaging systems may be realistic.

Search and preliminary analysis of new Galactic PNe

In general, the methods for searching new PNe exploit one of their characteristics and typically introduce a bias in the sample extracted. It is therefore important to perform PN searches based on different selection criteria. Some years ago we started a new search for PN candidates on the plates of the Palomar Near Infrared Photographic Survey of the Galactic Plane. The selection criterion is based on the consideration that PNe have I(R) > I(NIR) up to AV ∼ 10, whereas normal field stars have I(R) < I(NIR). First the plates are examined directly using a binocular, with a medium magnification, searching for faint diffuse nebulosity. Hereafter the comparison between R and NIR images is used both to detect new compact PN candidate and to discard, among diffuse objects, reflection nebulae. Spectra and imaging of the new objects were obtained in dedicated program both at the ESO and Asiago Observatories. From a preliminary analysis of the data for the new PNe it appears that the sample contains objects with very different characteristics. They have different morphologies and spectral features, but in general only few of the new PNe have an IRAS counterpart and these show a small flux in the IR. In particular, in the IRAS color-color plot they do not seem confined to the area of the bona-fide PNe; this still preliminary evidence may indicate that our selection criteria is pointing to PNe which remain undiscovered using other methods.

Collection deficiencies of scanning electron microscopy signal contrasts measured and corrected by differential hysteresis image processing

AbstractLimitations of scanning electron microscopy (SEM) image resolution and quality were measured in digital image data and their effect on image contrasts was analyzed and corrected by differential hysteresis (DH) processing. DH processing is a mathematical procedure that utilizes hysteresis properties of intensity variations in the image for a segmentation of differential contrast patterns. These patterns display contrast properties of the data as coherent full‐frame images. The contrast segmentation is revertible so that the original image can be restored from the sum of the sequentially extracted DH contrast patterns. DH imaging enhances weak contrast components so that they are more easily recognizable and displays SEM image data free of signal collection efficiency contrasts. Example image data include environmental SEM (ESEM) and SEM images of low and mediumhigh magnifications where collection deficiencies included charging of the specimen surface, obstructions from specimen topography, and uneven signal collection properties of the detector. ESEM low‐vacuum image data, which appear to be of high quality, contained local areas of reduced contrasts due to residual surface charging. In such areas, signal contrasts were reduced up to 80%, which suppressed most of the weak short‐range contrasts. In low‐magnification SEM images, up to 93% of the local high precision contrast was lost from the various adverse effects which diminished the pixel‐related contrast resolution of the microscope and resulted in images with low detail. Also, at medium magnification, surface charging effects dramatically reduced the image quality because contrasts resulting from local electron beam/specimen interactions were reduced by as much as 71%. DH imaging restored the local contrast losses by elimination of the collected distorted fraction of signal contrasts and reconstitution of the collected maintained fraction. Restored DH images are of superior quality and enhance the imaging capability of the conventional SEM. DH contrast segmentation provides an improved basis for the measurement of various signal contrast components and detector performances. The DH analysis will ultimately facilitate a precise deduction of specimen properties from extracted contrast patterns.

Observations of scanning electron microscopy detected abnormalities of non-lubricated latex condoms

To describe surface abnormalities found by scanning electron microscopy of non-lubricated latex condoms, thirty samples of 15 condoms were photographed at low (26–94x), medium (240–940x) and high (>1000x) magnification. Each sample was initially scanned at low magnification to determine the presence and location of surface abnormalities. Photographs taken at medium and high magnification were of the area most representative of the abnormality. Nine samples (30%) were completely normal at all magnifications. Of the total viewed at low power, 18 (60%) were normal, 11 (37%) revealed ridging and 1 (3%) revealed melting. Of the total viewed at medium power, 14 (47%) were normal, 3 (10%) showed cracking, 2 (7%) showed melting or a combination of ridging and cracking, and 11 (37%) showed ridging. At high power, 10 (34%) were normal, 11 (38%) revealed either melting or a combination of two defects, 5 (17%) showed ridging, and 3 (10%) revealed cracking. Fifteen (50%) of the samples revealed a surface abnormality (cracking or melting) other than ridging. The majority of condoms viewed under scanning electron microscopy revealed surface abnormalities. The implication of the detected abnormalities needs further evaluations. While ridging may represent a minor abnormality associated with condom handling, multiple abnormalities or melting may represent a more significant atypicality.

Application of Atomic Force Microscopy to Ultrastructural and Histochemical Studies of Fixed and Embedded Cells

Various methods of sample preparation were used to study the cellular ultrastructure with an atomic force microscope (AFM). A rather satisfactory fine structure of cellular cross section, that was comparable to low to medium magnification electron micrographs, was obtained when ultrathin sections of epoxy embedded materials cut with a diamond knife were examined by use of a non-contact mode. No surface treatment was necessary to image the surface contour of ultrathin sections. According to this method, cellular membranes appeared as an elevation in contrast to depression of the intercellular space and cytoplasm. The chromatin and nucleolus showed an elevated image against the depression of nucleoplasm, resulting in the formation of images comparable to those obtained by conventional transmission electron microscopy. In the section treated for post-embedding immunohistochemical reaction, colloidal gold particles larger than 10-15 nm in diameter could be detected as elevations. By means of Kelvin force probe microscopy (KFM), enhancement of the surface potential was detected at exactly the same location as topographically detected gold particles. Application of KFM is expected to become a valuable tool for novel histochemistry with the use of AFM.

Scanning force microscopy of diatom shells

We have imaged surfaces of several diatom species by scanning force microscopy with image areas of some squared micrometers. The algae cells were collected from a mud sample out of a small pond, rinsed briefly with ethanol to clean and immobilize them and deposited on a glass slide. The ease of obtaining images with a resolution of several ten nanometers makes the scanning force microscope competitive with scanning electron microscopy at medium magnification.

Dedicated image analysis techniques for three-dimensional reconstruction from serial sections in electron microscopy

This article describes the digital treatments needed to reconstruct spatial information at a 40-nm depth resolution of entire cells from transmission electron microscopic images of serial sections containing laser-induced topographical references. The use of a scanning transmission electron microscope (STEM) allows the acquisition of images with high contrast and good resolution at medium magnification. The scanning of our specimens at video frequencies is an attractive way to link a STEM with an image processing system. The magnetic hysteresis of the spools responsible for the electron scanning induces image deformations that have to be modelized and rectified before registering the images corrected for cutting-induced deformations.

A comparison of new microscopical techniques for the study of fossil spore wall ultrastructure

The two relatively new techniques of Scanning Acoustic Microscopy (SAM) and Laser Scanning Microscopy (LSM) are investigated for their potential use in studying fossil megaspore ultrastructure. Two Carboniferous ( Lagenicula and Setosisporites) and one Triassic megaspore ( Bowenispora) are used as examples. Comparisons of the conventional techniques of transmitted light, scanning and transmission electron microscopy are given. SAM and LSM provide useful additional tools for obtaining data on wall organisation. LSM particularly, provides good, medium magnification images of the spore exine.

Visualizing unstained neurons in living brain slices by infrared DIC-videomicroscopy

With a combination of infrared illumination, differential interference contrast (DIC) and image intensification by video, unstained living neurons have been visualized up to a depth of 50–100 μm in 300-μm thick brain slices. Recording and application pipettes could be placed under visual guidance. When applied to slices from rat neocortex and hippocampus, pyramidal and non-pyramidal neurons could be differentiated with medium magnification (20x–40x objective). Local neuronal clusters and bundling of apical dendrites by pyramidal cells were visible. The use of an objective with high numerical aperture (63x, N.A. 1.4) allowed the visualization of structures in the submicron range in neocortex and hippocampus. In combination with electrophysiological recordings, infrared DIC-videomicroscopy should facilitate the search for morphological changes underlying neuronal plasticity and the characterization of neuronal networks.

Scanning Transmission and Computer-Aided Volumic Electron Microscopy: 3D Modeling of Entire Cells by Electronic Imaging

The digital processing of electron microscopic images from serial sections containing laser-induced topographical references allows a 3-D reconstruction at a depth resolution of 30 to 40 nm of entire cells by the use of image analysis methods, as already demonstrated for Transmission Electron Microscopy (TEM) coupled with a video camera. (Cf ref)We decided to use a Scanning Transmission Electron Microscope (STEM) to get higher contrast and better resolution at medium magnification. The scanning of our specimens at video frequencies is an attractive and easy way to link a STEM with an image processing system (see Fig 1) but the hysteresis of the electronic spools responsible for the magnetic deviation of the scanning electron beam induces deformations of images which have to be modelized and corrected before registration. Computer algorithms developed for image analysis and treatment correct the artifacts caused by the use of STEM and by serial sectioning to automatically reconstruct the third dimension of the cells.(see Figs 2 and 3) They permit the normalization of the images through logarithmic processing of the original grey level information. The automatic extraction of cell limits allows to link the image analysis and treatments with image synthesis methods by minimal human intervention. The surface representation and the registered images provide an ultrastructural data base from which quantitative 3-D morphological parameters, as well as otherwise impossible visualizations, can be computed.

Development of an Autofocus System in Tem

An autofocus system has been developed by combination of a high-sensitivity TV camera, a 32-bit CPU with a frame memory, and TEM image wobbler function. Center-crossing line profiles of images, instead of 2D images, have been used for autofocusing, thus ensuring high speed autofocusing within 8∽24 seconds for the medium magnification range, × 2000 ∽ 50000.The image wobbler is a well-known function for a standard commercial TEM, and widely used for biological specimens. For autofocusing by using an image wobbler, the 2D image matching technique is extremely important, and some papers have been published. However, in image matching, image data has to be considered as large as 512×512×8 bits, thus requiring a long computation time. A new type of matching, line profile matching instead of image matching, can save much time and computer memory.

Über die histologische Differenzierung von Fettembolie und Silikonembolie nach extrakorporalem Kreislauf mit dem Beuteloxygenator

Introduction An attempt has been made to distinguish histologically fat embolism from silicone antifoam compound embolism occurring after extracorporeal circulation with the bubble oxygenerator (Clark, DeWall, Rygg-Kyvsgaard). Material and Methods 20 μ thick formalin fixed frozen sections from human brain and kidney were stained with hemalum-Sudan III, oil red O, Sudan black, nuclear fast red and hematoxylin-eosin. Some frozen sections were extracted with cold acetone and subsequently stained with Sudan III. Silicone antifoam compound was injected post mortem into arteries of brain and kidney. Frozen sections were prepared. Small pieces of brain and kidney were examined physico-chemically for content of Silicone antifoam compound. Slides ware examined at medium magnification using a small aperture of illumination (top lens of condensor turned out, diaphragm half closed). Results and Discussion Fat emboli measuring 10–15 μ in diameter and 15–60 μ in length and staining red with Sudan III were found in capillaries of cerebral cortex (Fig. 1) and glomeruli (Fig. 2). They were extractable with cold acetone. Silicone emboli measuring 10–20 μ in diameter and up to 90 μ in length were visible in capillaries of the same localization (Fig. 3 and 4). They did not take the Sudan III dye and remained transparent with a small dark margin. Cold acetone did not remove them from tissue sections. Microscopic examination of organs after intraarterial injection of Silicone antifoam compound (Fig. 5) and infrared spectrographical analysis of organ extracts prepared by chromatography (Fig. 6) support the above histological differentiation (Table 1).

Description of a Water Tunnel and Apparatus for the Investigation of Flow Problems

AbstractThe water tunnel, closed-return type, described in the paper is especially suitable for the observation of flow near the surface of a long streamline body of revolution at Reynolds numbers up to 1.3 × 106. The observation chamber is 32 ins. long and it has a circular cross-section of diameter 7 ins. The stream in the observation chamber although slightly disturbed at the higher speeds of flow is substantially free from turbulence (except near the wall) at all speeds and throughout its entire length.The tunnel is equipped with two instruments designed for flow observation. The first instrument, named fluid-motion microscope, allows the movements of small particles in a bright beam of light to be observed and measured. This instrument is suitable for the study of details of flow too small to be seen with the unaided eye, but which are revealed under a microscope at a medium magnification. The second instrument, the fluid-motion microscope with an interrupter, allows the speed of a particle to be determined from a measurement of the length of its track recorded for a known time of exposure on a photographic plate. This instrument can be used to measure the velocity distribution in a boundary layer to a distance of about four thousandths of an inch from the surface.