bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning Electron Microscopy of the Normal Rabbit Hepatocyte
Authors: Nopanitaya Waykin , Grisham Joe W. 
Published: June 2020

Current interest in the ultrastructure of the liver arises partly from demonstrations that scanning electron microscopy is very useful for studying surfaces and interrelationships of intrahepatic structures in both normal and pathological situations. In recent years, the development of the scanning electron microscope and techniques of tissue preparation has provided a three-dimensional method for examination of the features of intrahepatic ultrastructure. Only reports on the rat liver were available. However, SEM observations on the liver from other species are currently in progress in our laboratories. In this report, the SEM observations on the rabbit hepatocyte and the relevant technique for preparing hepatic tissues are described.Healthy, adult New Zealand rabbits were anesthetized by either intravenous or intraperitoneal injection of pentobarbital. Both abdominal and thoracic walls of anesthetized animals were opened. A small incision was made in the inferior vena cava at the level just below the renal veins, immediately followed by intracardiac perfusion of chilled 0.9% saline for 5 minutes.
The Network Parameters Of The T-System In Frog Muscle Measured With The High Voltage Electron Microscope.
Authors: Eisenberg Brenda R. , Peachey Lee D. 
Published: June 2020

Analysis of the electrical properties of the t-system requires knowledge of the geometry of the t-system network. It is now possible to determine the network parameters experimentally by use of high voltage electron microscopy. The t-system was marked with exogenous peroxidase. Conventional methods of electron microscopy were used to fix and embed the sartorius muscle from four frogs. Transverse slices 0.5-1.0 μm thick were viewed at an accelerating voltage of 1000 kV using the JEM-1000 high voltage electron microscope at Boulder, Colorado and prints at x5000 were used for analysis.The length of a t-branch (t) from node to node (Fig. 1a) was measured with a magnifier; at least 150 t-branches around 30 myofibrils were measured from each frog. The mean length of t is 0.90 ± 0.11 μm and the number of branches per myofibril is 5.4 ± 0.2 (mean ± SD, n = 4 frogs).
The Sarcoplasmic Reticulum of Frog Slow and Twitch Muscle Fibers as Revealed by Stereoscopic High Voltage Electron Microscopy
Authors: Bailey Craig H. , Peachey Lee D. 
Published: June 2020

Our present understanding of the distribution and morphology of the sarcoplasmic reticulum (SR) in frog slow and twitch muscle fibers has been derived largely from the examination of thin sections by electron microscopy. This conventional approach to the study of an organelle as complex as the SR is limited to a degree by section thickness, and the extraction of three-dimensional information must usually be gathered from an extensive collection of two-dimensional images. The present study represents an alternative approach to the problem of investigating the three-dimensional organization of the SR by utilizing high voltage electron microscopy (HVEM) and examining stereoscopic images of selectively stained 1.0 /μm thick slices of muscle tissue.Slow and twitch fibers from the distal fiber bundles of the frog (Rana pipiens) cruralis muscle were processed for electron microscopy according to the selective SR staining technique (DAB-H2O2 and Os-ferrocyanide) developed by Waugh. Tissue slices from 0.25 to 1.0 μm in thickness were cut on a diamond knife, mounted on grids either with or without plastic support films, and examined using the JEM-1000 microscope at the University of Colorado operating at an accelerating voltage of 1000 kV.
Lipopolysaccharide Embedded within the Exine of Pollen Grains
Authors: Rowley J. R. 
Published: June 2020

Recent observations indicate that sporopollenin cannot any longer be considered as the only major component of the exine. Filaments in great numbers are exposed from exines of Lycopodium spores heated to high temperatures and sporopollenin partially dissolved. The filaments have closely spaced anionic sites whereas sporopollenin is composed only of C, H, and O and is without carboxyl groups to explain the basophilia typical of exines. The exposed filaments of Lycopodium spore exines are similar in their resistance to the organic base 2-aminoethanol, reaction to basic dyes, and in morphology to lipopolysaccharide extracted from exines of Epilgbium pollen (Rowley, abst. & oral presentation for Scand. Soc. of E.M., Umea 1973).To isolate lipopolysaccharide (LPS), exines were dissolved in 2-aminoethanol at 130-140°C for 18 hrs. Following dialysis the residue was extracted with 45% aqueous phenol at 65-68°C. The large aggregates of LPS in water were separated from other non-dialysiable substances by ultracentrifugation.
Effects of Cytochalasin B on the Golgi Apparatus of Maize Root Cells
Authors: Mollenhauer H. H. , Morrè D. J. 
Published: June 2020

Seedlings of maize (Zea mays L.) var. WF-9 X M-14 were exposed to cytochalasin B for 1/2, 1, and 2 hr at concentrations of 0, 10, and 100 ppm. The root tips were then fixed for electron microscopy and the epidermal and outer cap cells examined for changes in dictyosome form, intercisternal fibers or secretory vesicles.Cytochalasin B did not cause significant changes in dictyosome form (Fig. 1) or intercisternal fibers. However, it did induce alterations in the distribution patterns of Golgi apparatus-derived secretory vesicles.In epidermal and outer cap cells of the maize root, following cytochalasin B treatment, secretory vesicles accumulated within the central portions of the cytoplasm in those regions occupied by Golgi apparatus (Fig. 2, 3). Cytoplasmic regions along the cell surface were devoid of secretory vesicles, and very few vesicles were found at the cell surface (Fig. 2, 3). We interpret these findings to mean that secretory vesicles formed by the Golgi apparatus did not move to the cell surface, but accumulated at or near their sites of origin following treatment with cytochalasin B.
Ultrastructural and Biochemical Evaluation of Parathyroid Function of Pregnant Cows Administered Disodium Ethane-l-Hydroxy-1, 1-Diphosphonate (EHDP) and Fed a Low Calcium Prepartal Diet
Authors: Yarrington J.T. , Capen C.C. , Black H.E. , Re R. , Potts J.T. , Geho W.B. 
Published: June 2020

EHDP is a synthetic analogue of pyrophosphate and a potent inhibitor of bone resorption. The objective of this investigation was to evaluate the effects of EHDP on the ultrastructure and function of parathyroid glands stimulated by feeding a low calcium diet to pregnant cows.Two groups of 3 pregnant cows each were fed a low calcium (5 gm/day) diet supplemented with phosphorus (25 gm/day) for approximately 70 days prepartum and up to 2 days postpartum. Cows of one group received a daily subcutaneous injection of EHDP (4 mg/kg/day). Cows of the second group received no EHDP. At parturition cows fed the low calcium diet remained clinically normal and had serum calcium and phosphorus values of 8.05 and 4.3 mg/100 ml, respectively (Fig. 1). EHDP-treated cows developed hypocalcemia (5.44 mg/100 ml), hypophosphatemia (1.49 mg/100 ml), and clinical signs pathogonomic for parturient paresis. Plasma immunoreactive parathyroid hormone (iPTH) levels were as high or higher both prepartum and postpartum than in cows only fed the low calcium diet.
Electron Microscopic Examination of DNA in an Alkaline Sucrose Gradient
Authors: Garner W. D. , Nordquist R. E. , Bottomley R. H. , Hawrylko J. M. 
Published: June 2020

The technique of lysing cells on top of an alkaline sucrose gradient prior to sedimentation was first designed to examine single stranded DNA from protoplasts. The lysis of mammalian cells and sedimentation of the released DNA has not been examined thoroughly by EM. The present work describes the ultrastructural characteristics of DNA species found after whole cell lysing and sedimentation of the DNA through an alkaline sucrose gradient.The DNA of H4-II-E rat hepatoma tissue culture cells was prelabelled with H3TdR (luci/ml) for 18 to 24 hours prior to lysis. Cells were layered into a lysing layer (0.1 M EDTA and 0.5 N NaOH, pH 13.25) on top of a 5-202or 5-25% alkaline sucrose gradient (0.01 M EDTA, 0.1 N NaOH and 0.9 M NaCl). After centrifugation the gradients were fractionated from the bottom. The fractions containing the majority of H3TdR were applied directly on grids at pH 8.5 or 12. Samples were stained with uranyl acetate.
A Modified Technic of Staining Elastic Tissue for Electron Microscopic Study
Authors: Nordquist J.A. , Chrysant K. , Mandal A.K. 
Published: June 2020

By electron microscopy elastic tissue appear electrolucent in osmium fixed unstained grids as well as grids stained with uranyl acetate and lead citrate (UA + LC). Albert and Fleischer have studied aorta of mice with metalloporphyrins imparting conspicuous electron density to the elastic tissue. We are reporting here a modified method of electron microscopic (EM) study of the elastic tissue using metalloporhyrin, silver tetraphenyl porphyrin sulfonate (STPPS).We have studied the renal arterioles of rats and human in normal and diseased states. Elastic tissue of the aorta from young normal rat served as control for this study. Renal and aortic tissues were fixed in 4 percent glutaraldehyde, post fixed in 1 percent osmium tetroxide and embedded in spurr (blocks). From the blocks of renal tissue, 0.5 μ sections were cut, stained with methylene blue and azure II and studied by light microscopy.
The Effect of Temperature on Coronavirus Replication
Authors: Jamison R. M. , Cowley L. H. 
Published: June 2020

Monolayers of human foreskin fibroblast cells were infected with a high input multiplicity of coronavirus 229-E. Virus was allowed to adsorb to the cells for 2 hours at 37°C. After this interval, one series of cell monolayers was covered with Eagle's minimal essential medium with 2% bovine serum warmed to 33°C and incubated in an atmosphere of 5% CO2 at 33°C. Another cell monolayer series was covered with the same medium at 37°C and incubated in an atmosphere of 5% CO2 at 37°C. At appropriate intervals, cultures were switched from 33°C to 37°C and incubated for a total of 24 hours post-inoculation. After incubation, all cultures were harvested for titration of infectious virus or electron microscopy.The monolayers for electron microscopy were fixed in 6% glutaraldehyde, post-fixed in 2% OsO4 in Clark's buffer, dehydrated in an ethanol series, and embedded in Epon 812. Ultra-thin sections were prepared and double stained with lead citrate and uranyl acetate.
Development of Methodology for Low Exposure, High Resolution Electron Microscopy of Biological Specimens
Authors: Ai-Ming Kuo Ivy , Glaeser Robert M. 
Published: June 2020

Specimen damage in the electron microscope due to the inelastic scattering of the incident electrons is one limitation to obtaining high resolution image data of biological specimens. For most organic molecules, when the electron exposure reaches 10-3 Coulomb/cm2, further observation will provide no information concerning the original structure. Therefore, in order to obtain high resolution data, the exposure must not exceed this value. At this exposure, the resulting image will be a statistically noisy one. In our work, we investigated the feasibility of improving the signal to noise ratio in the image of a periodic specimen, by spatially averaging the statistically noisy images of all the unit cells.Using a carbon replica of an optical diffraction cross grating(54800 lines/ inch) as our test specimen, the statistically noisy image was recorded with an image intensifier at the magnification of xl600 and at the exposure of 3xl0-4electron/ μm2 on the image plane (Fig. 1a).
Experimental Determination of the Effective Resolution Limit in Thick Specimens at High Voltages
Authors: Fotino Mircea 
Published: June 2020

The use of thick specimens (0.5 μm to 5.0 μm or more) is one of the most resourceful applications of high-voltage electron microscopy in biological research. However, the energy loss experienced by the electron beam in the specimen results in chromatic aberration and thus in a deterioration of the effective resolving power. This sets a limit to the maximum usable specimen thickness when investigating structures requiring a certain resolution level.An experimental approach is here described in which the deterioration of the resolving power as a function of specimen thickness is determined. In a manner similar to the Rayleigh criterion in which two image points are considered resolved at the resolution limit when their profiles overlap such that the minimum of one coincides with the maximum of the other, the resolution attainable in thick sections can be measured by the distance from minimum to maximum (or, equivalently, from 10% to 90% maximum) of the broadened profile of a well-defined step-like object placed on the specimen.
Phase Separation in Shock Consolidated Amorphous Powder
Authors: Thadhani Naresh , Mutz Andrew H. , Vreeland T. 
Published: June 2020

During shock-wave consolidation of irregularly shaped (≌50 μm diameter) Marko-met 1064 powder (Ni55.8Mo25.7Cr9.7B8.8), obtained from melt-spun ribbon, the shock energy is preferentially input at particle surfaces. Heat flow to particle interiors is sufficiently rapid to quench melted regions and form the amorphous phase at shock energies less than about 400 kJ/kg.Amorphous powder was rolled between two 100 μm thick sheets. Discs cut from the composite strip and sections of a consolidated sample (shock energy ≌325 kJ/kg) were electrolytically jet thinned (at -25°C and -50°C) for TEM examination in a Philips EM 420 TEM/STEM.Figure 1 is a stereo pair taken at an interparticle melted and resolidified region in the compacted powder specimen. The microstructure exhibits a dispersion of fine amorphous spherical phase (diameter ≌0.01 to 0.08 μm), randomly distributed in a continuous amorphous matrix.
Precipitation and Recovery Near Interparticle Regions In Explosively Consolidated 304 Stainless Steel Rapidly Solidified Powders
Authors: Schoenlein L. H. , Korth G. E. , Flinn J. E. 
Published: June 2020

Rapid solidification often produces new and unique alloy microstructures. Retention of these microstructures may be accomplished by dynamic consolidation, the bulk temperature rise generated by this technique is quite low. However, at near-surface regions of powder particles the temperature rise can be substantial and may cause extensive recovery, recrystallization or remelting of these areas.Examination of explosively-consolidated 304 stainless steel powders produced by dissolved gas atomization was performed by TEM. Particle interiors contained copious dislocations, twins and stacking faults, typical of shock-hardened materials. Some interparticle regions (Figure 1) contained few structural defects, apart from a network of low angle boundaries, indicating that extensive recovery occurred. The extent of these areas is typically ∼5 μm and the average subgrain is ∼0.5 μm in diameter. Precipitation also occurred in these areas, as discussed below, but was not observed in the particle interiors.
Identification of Metastable Phases Using Convergent Beam Electron Diffraction
Authors: Fraser Hamish L. 
Published: June 2020

The use of convergent beam electron diffraction in the characterization of microstructures of rapidly solidified materials is described. In view of the imposed length restrictions of this paper, one example of metastable phase identification is given. At the meeting, the critical factors involved in this type of analysis will be reviewed.The example given here is taken from a study of melt-spinning of Al-Ge alloys. In an Al-36Ge (atomic %) alloy, the type of microstructure observed in melt-spun ribbons is shown in fig. 1. A dendritic structure is seen to be surrounded by either an interdendritic second phase or a eutectic mixture. Selected area diffraction patterns obtained from this primary dendritic phase could not be indexed as either α-Al or β-Ge; since the phase diagram indicates that only these latter two solid phases are expected to be present in alloys of this composition, it is concluded that this is a metastable crystalline phase.
Failure of the Conservation of Flux in the Dynamical Theory of the Electron Diffraction
Authors: Kim H. S. , Sheinin S.S. 
Published: June 2020

It is widely believed that flux is conserved in the dynamical theory of electron diffraction. Conservation of flux requires thatwhere ϕg is the amplitude of a diffraction beam and the sum is over all diffracted beams. (1) is valid if the crystal is assumed to be non-absorbing and if reflected waves are neglected. It can also be shown that (1) only holds if the eigenvectors of the dynamical matrix are orthogonal. Orthogonality of these eigenvectors is, however, only obtained when certain approximations and assumptions are made including, for example, the column approximation and the assumption of symmetrical Laue diffraction conditions.In order to see the possible effects of relaxing these assumptions and approximations on conservation of flux, consider the expression for diffracted beam amplitude in non-symmetrical Laue casewhere the summation is over all Bloch waves excited in the crystal.
The Mechanism of Gunshot Residue Deposition And Its Probing Characteristics to Reconstruct Shootings
Authors: Basu S. 
Published: June 2020

Gunshot residue (GSR) studies by glue-lift were conducted to determine the mechanism of GSR deposition and its probing characteristics that had been essential to reconstruction of shootings in self-inflicted deaths, and have been immensely useful to interpretation of the GSR distribution on a suspect's or victim's hands.Unlike many solid vapors that grow as various forms of crystals, GSR particles form mainly as spheroids (diameter mainly 0.5-55 μm, Fig.1) by solidification of lead, antimony and barium-containing vapors of melted primer when a bullet is discharged from its cartridge with a firearm. The molten condensate morphologies of GSR when combined with the elemental composition (Pb, Sb, Ba), makes GSR quite distinct from many environmental and occupational particulates, which may contain one or more elements of GSR.
Preparation of TEM Specimens From Highly Radioactive Materials
Authors: McCarthy J. M. , Thomas L. E. 
Published: June 2020

Intense radioactivity from nuclear materials such as irradiated UO2 and high-level waste glass often makes it impractical to prepare specimens of these materials for transmission electron microscopy. This paper describes a technique that yields ion-milled TEM specimens of reasonably low total activity from highly radioactive materials. Finished specimens each consist of a 3 mm diameter annular support ring that contains a small particle of sample, typically 50 to 300 μm in diameter and 5 to 10 μm in thickness, in epoxy. Although the application to nuclear materials is highly specialized, the basic preparation method requires only readily obtained materials, the simple grinding jig shown in Fig. 1 and an ion micromill for final specimen thinning.The specimen preparation procedure is as follows: A 3 mm diameter washer, 0.15 mm in thickness with a 0.5 mm central hole, is placed over a 50 to 300 μm diameter particle on Parafilnn and the resulting well containing the particle is filled with epoxy.
Electron Beam Induced Desorption: W on WO3
Authors: Marks L.D. , Petford A.K. , O'Keefe M. 
Published: June 2020

We report here direct observation within an HREM of an electron beam induced desorption process by the Knotek-Feibelman or KF mechanism [1]. Results were obtained for both ground WO3 crystals and WO3 smoke, in both cases supported on holey carbon films and examined in a JEOL 200CX. The results are shown in Figures 1-4, the main features of which are:1)Formation of at least 2-3 layers of the metal epitaxed in the relationship W(110)//WO3(100), W[001]//WO3[001], a near coincident site epitaxy [2] with 6 WO3(100) matching 10 W(110).2)No evidence of a W03-x or layer near the surface, ruling out thermal decomposition mechanisms.3)A fairly uniform coverage indicating that the metal wets the ceramic surface.
The Microstructual Characterization of Boron Ion Implanted Silicon During Amorphization Process
Authors: Shih Yih-Cheng , Washburn Jack 
Published: June 2020

Two amorphization models, heterogeneous and homogeneous nucleation have been used to describe heavy ion implantation at low temperature and light ion implantation at high temperature by many authors. However, the amorphization mechanism for light ion damage is still unclear. Cross section views of the amorphous-crystalline transition region afford a continuous picture of the crystalline to amorphous transformation process. In this work, high resolution cross-section TEM has been used to clarify the amorphization mechanism for silicon implanted with Boron ions at various temperatures and dose rates.A cross section view is shown in Fig. 1, of silicon implanted with 1x1016/cm2 Boron ions at room temperature and 80 KeV energy. It shows that small spots first gather around near the depth of peak damage (∼2300A below the surface). High resolution images of these spots reveals that they are damage zones losing periodic atom arrangement (Fig. 2). The Electron Paramagnetic Resonance Spectrum from the same specimen contains an isotropic amorphous peak.
Complementary Z-Contrast Imaging and Digital Image Processing
Authors: Colonna K. N. , Oliphant G. 
Published: June 2020

Harmonious use of Z-contrast imaging and digital image processing as an analytical imaging tool was developed and demonstrated in studying the elemental constitution of human and maturing rabbit spermatozoa. Due to its analog origin (Fig. 1), the Z-contrast image offers information unique to the science of biological imaging. Despite the information and distinct advantages it offers, the potential of Z-contrast imaging is extremely limited without the application of techniques of digital image processing. For the first time in biological imaging, this study demonstrates the tremendous potential involved in the complementary use of Z-contrast imaging and digital image processing.Imaging in the Z-contrast mode is powerful for three distinct reasons, the first of which involves tissue preparation. It affords biologists the opportunity to visualize biological tissue without the use of heavy metal fixatives and stains. For years biologists have used heavy metal components to compensate for the limited electron scattering properties of biological tissue.
Thermal Aging Of Primary Coolant Pipe Steel
Authors: Miller M. K. , Bentley J. , Brenner S. S. , Spitznagel J. A. 
Published: June 2020

The long term mechanical integrity of the pipes used to carry the primary cooling water in a pressurized water nuclear reactor is of the utmost importance for safe operation. A combined atom probe field-ion microscopy (APFIM) and transmission electron microscopy (TEM) study was performed to characterize the microstructure of this cast stainless steel and to determine the changes that occur during long-term low-temperature thermal aging.The material used in this investigation was a commercial CF 8 type stainless steel with a bulk chemical composition as given in Table 1. The steel was examined in the as-cast, unaged condition and also after aging for 7500 h at 673K. This temperature is 100K higher than the normal service temperature and was chosen to accelerate the microstructural changes that may occur during service. As these pipes are external to the reactor they are not exposed to any significant radiation that may influence the aging behavior.