bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relevancy of electron microscopy in the study of male factor in conjugal infertility
Authors: Gallegos M.G. , Ramírez E. , Eguia R.M. , González D. , Díaz O. 
Published: June 2020

In recent years, the study of male factor in conjugal infertility, has received more attention since it was recognized as an important cause of infertility in 30-50% of the cases; and to the diminishing quality of semen, observed during the last decades, possibly related to environmental polution.Alterations in sperm motility has been included as a direct cause of male infertility along with the traditionally known causes. Frequently these alterations have been related to morphological changes of spermatozoa. The morphology and size of sperm cells are higly variable in human semen and abnormal forms also can be found in fertile men. Experimental data demonstrate that abnormal spermatozoa are not functional cells. There are many clinical reports that associate spermatic dismorphy with infertility. Previously reported abnormalities in the sperm morphology related to infertility include: acrosomal agenesis, defects in the dynein arms and fibrous sheath displasia. Therefore, it is important to undertake the ultrastructural study of spermatozoa to determine subcellular pathology of the gamete which could explain the reproductive failure, specially if there is no evident cause of the motility defect or if there has been no response to treatment, or if the assisted reproductive programs have failed repeatedly.
Subcellular localization of the latent membrane protein LMP-1 in Epstein-Barr virus infected cells by immunogold EM
Authors: Misra D. N. , Agostini R. M. , Yunis E. J. 
Published: June 2020

Epstein-Barr virus (EBV) infection, prevalent in all human populations, is clinically silent in general, but causes infectious mononucleosis in some adolescents and B-lymphocyte proliferative disorders (LPDs) in immunocompromised individuals (e.g. AIDS infected; allograft recipients). EBV is also etiologically associated with African Burkitt’s lymphoma, nasopharyngeal carcinoma, and Hodgkin’s disease. The virus infects B lymphocytes and transforms them into lymphoblastoid cells which proliferate indefinitely in culture. The latently infected cells express an array of EBV gene products including 6 nuclear antigens (EBNAs), terminal proteins LMP-2A and LMP-2B, latent membrane protein LMP-1, and untranslated RNAs EBER 1 and EBER 2. These components are being extensively studied since they are involved in latency or proliferative transformation; LMP-1 has also shown oncogenic properties. In this work, we have used immunogold electron microscopy for precise subcellular localization of LMP-1 in EBV infected cell lines.Two human cell lines, P3HR-1 (Burkitt’s lymphoma) and CCL-113 (Hodgkin’s disease), obtained from ATCC, were grown in RPMI 1640 containing 20% fetal calf serum, 100 U/ml penicillin and 100 μg/ml streptomycin.
Juvenile nephronophthisis: A case report
Authors: Price George , Cerezo Lizard , Pryor Norman 
Published: June 2020

Nephronophthisis, or the deterioration of nephrons, is a classification of congenital kidney disorder that results in a medullary cystic disease. The three variations of genetic expression for this disease are: 1. Sporadic occurrences where family history is negative for renal disease. 2. Recessive inheritance with or without other associated abnormalities. 3. Transmitted inheritance that is dominant with probable autosomal, and possible X-linked trait.Nephronophthisis is reported to occur between the ages of 2 to 68 years of age, with most appearing in the first three decades of life. The most common clinical presentation is chronic renal failure, with a history of polyuria, and polydipsia. Children and adolescents may also exhibit enuresis, and chronic anemia.Light microscopic examination of kidney biopsy tissue reveals extensive tubular atrophy accompanied by glomerular sclerosis, and inflammation resembling pyelonephritis. Tubules that are cystically dilated may be observed primarily at the cortico-medullary junction, although this finding is dependent on the extent of the disease process.
Ultrastructural study of skeletal muscle invasion by a malignant fibrous histiocytoma
Authors: Finol H. J. , Márquez A. , Bello B. , Rivera H. 
Published: June 2020

Cancer grows by progressive invasion, infiltration and destruction of tissues surrounding primary tumors or their metastases. Although this process has been amply investigated, it has not been adequately studied by means of electron microscopy and scarce information exists about its morphological aspects; Because of these reasons, we studied the ultrastructure of skeletal muscle invasion by a malignant fibrous histiocytoma as an example of the cancer growing process.Biopsies were obtained from a mass located intramuscularly in the left thigh of a 70 years old male patient. Samples were taken from the tumor and the surrounding muscle tissue. The specimens were processed with routine techniques for transmission electron microscopy and observed in a Hitachi H-500 electron microscope.The histopathological picture of the tumor fell within the spectrum for malignant fibrous histiocytoma. The borderline zone between tumor cells and muscle tissue was carefully examined. Tumor cells were located in the extracellular space. Muscle fibers were not found invaded but those beside tumor cells exhibited several alterations including atrophy (Fig. 1) and vacuolation (Fig. 3).
Utilization of scanning Electron Microscopy/Energy-Dispersive x-ray microanalysis to detect an immunogold labeled virus on a Transmission Electron Microscope thin sectioned sample
Authors: Helmick C. M. , Bailey J. F. , Ristow S. S. 
Published: June 2020

Since not all research facilities have access to a transmission electron microscope (TEM) / x-ray microanalysis system, a study was conducted to determine if a scanning electron microscope (SEM) equipped with an energy dispersive x-ray microanalyer would detect and quantify an immunogold labeled virus on a TEM thin sectioned sample. The objectives of the study were to first, demonstrate that a particular region (serous cardiac gland) of a thin sectioned fish esophageal tissue sample could be detected on a SEM. Secondly, we sought to demonstrate that the quantities of colloidal gold x-rays emitted were in association with the viral infected esophageal tissue at 1 and 24 hours post infection.Tissue and Immunogold labeling. Juvenile rainbow trout (Oncorhychus mykiss) were challenged in vivo at 105 pfu with Hagerman infectious hematopoietic necrosis virus (IHNV) or mocked infected with phosphate buffered saline (PBS). Fish were killed and fixed in 6% paraformaldehyde and 0.5% glutaraldehyde in 0.1 M PBS at 1 and 24 hours post infection and stored at 4°C.
Three-Dimensional Reconstruction reconstruction of A Z band from rigor skeletal muscle
Authors: Schroeter J.P. , Edwards R.J. , Goldstein M. A. 
Published: June 2020

We have produced three dimensional reconstructions of several regions of the Z band and the nearby I band in rat soleus muscle in rigor. The reconstructions were calculated using weighted back-projection techniques on electron micrograph tilt series taken about two orthogonal axes. Examination of cross-sections of the reconstructed Z bands reveal that the lattice is in the basket-weave form. We have previously shown that this form of the Z band lattice predominates in the muscle in rigor. The reconstructions reveal a dense net of cross-connecting Z-filaments in the Z band, which interconnect the axial filaments in a projected four-fold array.The Z band lattice spacing was measured as 27 +− 4 nm, consistent with values seen in electron micrographs of cross sections of this muscle. The Z spacing and the form of the lattice show little distortion from that observed in cross sections, despite a beam induced change in section thickness from ∼80 to 45 nm. This suggests that, as in previous Z band reconstructions in unstimulated muscle, section shrinkage in the Z band does not occur by means of a uniform collapse throughout the section.
Quick large-piece diagnostic electron microscopy processing
Authors: Valdivieso Teresa P. , Valaitis Jonas 
Published: June 2020

In the past submissions of tissue (fine needle biopsies of kidney, liver, incisional biopsies, tumors and miscellaneous other biopsies) for transmission electron microscopy examination were small, i.e. no larger than 1mm cubed (1,2). With such submissions, from the time the specimen was received in the electron microscopy laboratory until photographic prints were available and a diagnosis reported by the pathologist was 72 hrs. A modification of the standard procedure allows the processing of larger and thinner pieces of tissue up to 5mm × 3mm × .5mm and shortens the turn-around time from 72 hrs to 24 hrs.Large pieces of tissue are processed according to the procedure detailed below. All the usual steps are abbreviated: Primary fixation and post-fixation: 5 hrs; dehydration: 20 min; infiltration in epoxy resins: 1 hr and 25 min; embedding and orientation of specimens: 15 min; polymerization: 60 min; cutting thick and thin sections: 50% fewer blocks in comparison to previous procedure; staining in heavy metals: no change.
Ultrastructure of metaphase chromosomes and interphase nuclei
Authors: Woods Philip S. , Ledbetter Myron C. , Van't Hof Jack 
Published: June 2020

Electron microscopy of whole-mount preparations of chromosomes and nuclei was greatly improved upon over earlier studies, when techniques were developed to expand the specimen and to preserve the expanded state during drying. When the earlier procedures were followed, the thick and dense chromosomes and nuclei always appeared nearly opaque to the electron beam and yielded little information regarding internal structure. With the newer techniques, it has been possible to study structure in detail deep within these specimens. The chromosomes of the plant Vicia faba are composed of a very long thin (5-20 nm) fiber which consists of about 38% DNA, with a presumed equal amount of histones; and a thicker 15-55 nm net-like component consisting of the remaining 24%, as nonhistones. Our interests concern determining the structural relationship of these components in chromosomes and nuclei of root-tip cells of this same plant.Fig. 1 shows a Vicia faba metaphase chromosome expanded with EDTA and processed by freeze-substitution. Inset, at the same magnification, shows an untreated similarly processed control chromosome.
Basic literacy in electron-probe x-ray microanalysis with energy-dispersive x-ray spectrometry: Qualitative and quantitative analysis
Authors: Newbury Dale E. 
Published: June 2020

Rigorous electron probe x-ray microanalysis (EPMA) with energy dispersive x-ray spectrometry (EDS) takes place in two sequential steps: qualitative analysis followed by quantitative analysis.Qualitative analysis: Qualitative analysis involves the assignment of the peaks found in the x-ray spectrum to specific elements. One of the most important attributes of energy dispersive x-ray spectrometry (EDS) for qualitative analysis is that we can always view the complete x-ray spectrum. The EDS photon detection process effectively provides parallel detection in energy. Depending on the detector window and spectrometer characteristics, the entire energy range from Be K radiation (0.106 keV) to the incident beam energy can be available for analysis. With an incident beam energy of 15 keV, at least one family of x-ray lines (K, L, or M shell) will be excited for each element in the Periodic Table with atomic number ≥ 4. We ignore at our peril this capability to do a complete qualitative analysis at all specimen locations that we choose to measure. Quantitative analysis is meaningless if qualitative analysis has not been properly perfonned first. The bases for qualitative analysis include the exact energy of the peak(s), which places a premium on spectrometer calibration, the recognition of all members of each x-ray family and the possibility of two (or more) families being excited, the relative intensities ("weights of lines") within a family, and the artifacts associated with each high intensity peak, particularly the escape peak(s) and sum peak(s).
Immunoelectron microscopy of frozen hydrated blood platelets
Authors: O’Toole E. T. 
Published: June 2020

We have previously shown that ultrarapid freezing followed by cryomicroscopy provides a uniquely effective preservation of platelet ultrastructure, particularly in its cytoskeleton and membrane systems. However, a limitation of cryomicroscopy of frozen hydrated specimens is the lack of information about the localization of specific proteins within the cell. Methods for immunolocalization of antigens on material that has been rapidly frozen, freeze-substituted and embedded in immunocompatible resins have excited considerable interest among biologists, because of the high quality of preservation afforded by fast-freezing techniques. However, the extent to which fixation and dehydration affect the distribution of antigens is not known. Here we describe a method for imaging immunolabeled cells in the frozen hydrated state, avoiding the destructive steps of dehydration.Blood platelets were isolated from citrated whole blood by differential centrifugation and washed in Hank’s balanced salts. Washed platelet suspensions were placed on formvar coated, carbon stabilized gold finder grids and placed in a humid chamber at 37°C for 30 minutes to allow adhesion and spreading of the cells.
A basic introduction to image processing using NIH-Image as a model
Authors: Mansfield John 
Published: June 2020

Advances in camera technology and digital instrument control have meant that in modern microscopy, the image that was, in the past, typically recorded on a piece of film is now recorded directly into a computer. The transfer of the analog image seen in the microscope to the digitized picture in the computer does not mean, however, that the problems associated with recording images, analyzing them, and preparing them for publication, have all miraculously been solved. The steps involved in the recording an image to film remain largely intact in the digital world. The image is recorded, prepared for measurement in some way, analyzed, and then prepared for presentation.Digital image acquisition schemes are largely the realm of the microscope manufacturers, however, there are also a multitude of “homemade” acquisition systems in microscope laboratories around the world. It is not the mission of this tutorial to deal with the various acquisition systems, but rather to introduce the novice user to rudimentary image processing and measurement.
Quantitative Electron Microscope with imaging plate
Authors: Shindo D. 
Published: June 2020

Imaging plate has good properties, i.e., a wide dynamic range and good linearity for the electron intensity. Thus the digital data (2048x1536 pixels, 4096 gray levels in log scale) obtained with the imaging plate can be used for quantification in electron microscopy. By using the image processing system (PIXsysTEM) combined with a main frame (ACOS3900), quantitative analysis of electron diffraction patterns and high-resolution electron microscope (HREM) images has been successfully carried out.In the analysis of HREM images observed with the imaging plate, quantitative comparison between observed intensity and calculated intensity can be carried out by taking into account the experimental parameters such as crystal thickness and defocus value. An example of HREM images of quenched Tl2Ba2Cu1Oy (Tc = 70K) observed with the imaging plate is shown in Figs. 1(b) - (d) comparing with a structure model proposed by x-ray diffraction study of Fig. 1 (a). The image was observed with a JEM-4000EX electron microscope (Cs =1.0 mm).
Off-axis electron holography of a two-phase polymer
Authors: Libera M. , Gajdardziska-Josifovska M. , Disko M. M. 
Published: June 2020

Electron holography enables retrieval of phase from an image wave. This phase information is lost in conventional microscopy. As part of an ongoing program to study polymer microstructure via phase-contrast imaging, we report here our first experiences applying off-axis holography to polymers.This study utilized a 48k mw styrene/butadiene diblock copolymer mixed with 30% 25k mw styrene homopolymer. The specimen was cast from toluene, annealed, cryomicrotomed, and osmium stained. Offaxis electron holography experiments were performed at Arizona State University using the Philips 400STFEG microscope operated at 100kV. Digital holograms with =0.25nm fringes, 520kx magnification and Is exposures were recorded using a Gatan slow-scan CCD camera. Numerical hologram reconstruction was performed employing Gatan's Digital Micrograph.Figure 1 shows a diffraction contrast image of the specimen showing alternating styrene-rich (light) and butadiene-rich (dark) lamellae. Absolute phases were obtained from holograms in which vacuum was used as reference (region A in Fig. 1). Typical reconstructed amplitude and phase images from region A are shown in Fig. 2.
Molecular routes to the formation of ordered inorganic arrays
Authors: Hey wood Brigid R. , German Caroline 
Published: June 2020

Anisotropic inorganic materials are desirable as they possess unique physical and chemical properties resulting from the manner in which the particulate components assemble. The facility to control the ordering of colloidal inorganic particles could presage dramatic improvements in the fabrication of ceramics, catalysts or paints. Biological systems have already harnessed the manifold advantages of such materials, consider shells, teeth, bones etc.(Figures 1 & 2). Synthetic strategies for the formation of nanodimensional inorganic solids abound but there are few reliable methods currently available for directing their subsequent aggregation. Some degree of ordering can be achieved by the application of external forces (magnetic, electrical) but the aggregates readily dissemble once the stimulus is removed. The requirement is, therefore, for an effective molecular route to the ordered assembly and construction of hierarchical inorganic microstructures.The present work forms part of an extended programme of research investigating crystal tectonics, the ordering of nanodimensional inorganic solids. Here, the controlled morphological tailoring of inorganic crystals to yield a form which favours self-assembly has been investigated.
Interfacial structures of dissimilar materials joined by capacitor-discharge welding
Authors: Doğan C. P. , Wilson R. D. , Hawk J. A. 
Published: June 2020

Capacitor Discharge Welding is a rapid solidification technique for joining conductive materials that results in a narrow fusion zone and almost no heat affected zone. As a result, the microstructures and properties of the bulk materials are essentially continuous across the weld interface. During the joining process, one of the materials to be joined acts as the anode and the other acts as the cathode. The anode and cathode are brought together with a concomitant discharge of a capacitor bank, creating an arc which melts the materials at the joining surfaces and welds them together (Fig. 1). As the electrodes impact, the arc is extinguished, and the molten interface cools at rates that can exceed 106 K/s. This process results in reduced porosity in the fusion zone, a fine-grained weldment, and a reduced tendency for hot cracking.At the U.S. Bureau of Mines, we are currently examining the possibilities of using capacitor discharge welding to join dissimilar metals, metals to intermetallics, and metals to conductive ceramics. In this particular study, we will examine the microstructural characteristics of iron-aluminum welds in detail, focussing our attention primarily on interfaces produced during the rapid solidification process.
Dependence of growth stress on microstructure in periodic nanometer layered thin-film coatings
Authors: Nguyen Tai D. , Underwood James H. 
Published: June 2020

Sputtered x-ray multilayer coatings usually exhibit the presence of intrinsic stress in the structures. Stress in the coatings are undesirable in many x-ray optical applications where flat mirrors, or precise control of curved mirrors, are designed. Controlling of the stress in these multilayers requires understanding of stress and microstructural evolution in multilayers and thin films.Stress in thin films can be determined by the amount of bending or curvature of the substrate caused by the films. For a film deposited on a flat substrate, stress in the film is measured by using the laser scanning technique. The change in the curvature of the film and substrate is determined fromthe reflection profile fo the incident laser.For the usual case of a substrate that is elastically isotropic in the plane of the film, the expression of the biaxial stress in the film is given by the Stoney equation:for the case in which the thickness of the films is usually much less than that of the substrate, where E and γ are the substrate biaxial modulus and Poison ratio, ts and tare the substrate and film thicknesses, and K is the substrate curvature.
Local atomic structure of relaxor ferroelectric solids studied by pulsed neutron scattering
Authors: Egami T. , Rosenfeld H. D. , Teslic S. 
Published: June 2020

Relaxor ferroelectrics, such as Pb(Mg1/3Nb2/3)O3 (PMN) or (Pb·88La ·12)(Zr·65Ti·35)O3 (PLZT), show diffuse ferroelectric transition which depends upon frequency of the a.c. field. In spite of their wide use in various applications details of their atomic structure and the mechanism of relaxor ferroelectric transition are not sufficiently understood. While their crystallographic structure is cubic perovskite, ABO3, their thermal factors (apparent amplitude of thermal vibration) is quite large, suggesting local displacive disorder due to heterovalent ion mixing. Electron microscopy suggests nano-scale structural as well as chemical inhomogeneity.We have studied the atomic structure of these solids by pulsed neutron scattering using the atomic pair-distribution analysis. The measurements were made at the Intense Pulsed Neutron Source (IPNS) of Argonne National Laboratory. Pulsed neutrons are produced by a pulsed proton beam accelerated to 750 MeV hitting a uranium target at a rate of 30 Hz. Even after moderation by a liquid methane moderator high flux of epithermal neutrons with energies ranging up to few eV’s remain.
Microstructural development in solution-derived PZT thin films
Authors: Headley T. J. , Tuttle B. A. , Voigt J. A. , Michael J. R. 
Published: June 2020

Lead zirconate titanate (PZT) thin films are of technological interest for a variety of electronic and optical applications such as nonvolatile memories, decoupling capacitors, infrared detectors, and optical storage media. Fabrication of PZT films by solution deposition techniques is attractive because of uniform, stoichiometric control at the molecular level, ease of processing, and both low capital investment and total cost. Control of phase evolution, microstructure, crystallite size and orientation, and ferroelectric domain assemblage during processing is essential to optimize electrical and/or optical properties of the films. Factors which play a major role in controlling these parameters are details of the solution chemistry and mixing, thermal processing, Pb stoichiometry, Zr/Ti ratio, and substrate characteristics. Electron microscopy techniques have been used extensively to correlate microstructural features with film processing parameters as will be emphasized in this presentation.As annealing temperature is increased, phase evolution in PZT thin films typically proceeds from amorphous to pyrochlore to the ferroelectric perovskite phase. Fine-grained pyrochlore crystallizes from the amorphous film at low annealing temperatures and also precedes crystallization of the perovskite phase at higher temperatures. There is evidence that the Zr/Ti stoichiometry influences the microstructure of the amorphous-to-pyrochlore transformation.