bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Unique Features in Compound Eyes of Two Isopods
Authors: Nemanic Paula 
Published: June 2020

I have observed certain unique features in the ultrastructure of the compound eyes of the terrestrial isopod crustaceans Porcellio scaber and Armadillidium vulgare, using both scanning and transmission electron microscopy.Only about twenty ommatidia, arranged into four rows, constitute an eye, giving the organ the appearance of a cluster of grapes (Fig. 1). A few trichoid sensilla are interspersed between the ommatidia.The dioptric apparatus of each ommatidium is composed of a biconvex, cuticular lens and an underlying spherical crystalline cone. In these isopods each crystalline cone is the secretion of only two cells (Fig. 2), rather than four as in most malacostracans. The suture line between the two cone hemispheres is always parallel to the long axis of the ommatidium.
The Development of the Outer Plexiform Layer of the Mouse Retina
Authors: Blanks Janet C. , Adinolfi Anthony M. , Lolley Richard N. 
Published: June 2020

In the all-rod retina of the adult mouse, synaptic contacts in the outer plexiform layer occur between photoreceptor terminals and dendritic processes of horizontal and bipolar cells. The postnatal development of the outer plexiform layer has been studied by light and electron microscopy. Following decapitation and enucleation of the eyes, samples of retinae from DBA mice (newborn to fourteen days) were removed and fixed by immersion in solutions of buffered glutaraldehyde and paraformaldehyde. The tissue was postfixed in osmium tetroxide, dehydrated and embedded in araldite. Sections were stained with uranyl acetate and lead citrate.With light microscopy, the outer plexiform layer first appears in the central retina as a gap within the neuroblastic layer on the fifth postnatal day. The separation is completed by the seventh postnatal day and appears mature by the fourteenth postnatal day.
A Device for Embedding Epon Thick Sections for Electron Microscopy
Authors: Swoveland P. , Baringer J. R. 
Published: June 2020

A method has been devised for re-embedding 4-10 micra epon thick sections for thin sectioning. By using this method, multiple areas of a single tissue block are available for examination by electron microscopy without the destruction of deeper levels of tissue during the trimming process.Section mounting devices have been described by Woodcock and Bell and Ries. Both of these devices are designed to mount several thick sections on epoxy blocks against a single foil-coated microscope slide. However, this requires that several thick sections be available for re-embedding simultaneously. In addition, the sections cannot be observed during the process of flattening them against the microscope slide, and therefore perfect flatness cannot be assured.
Erythrophagocytosis by Entamoeba histolytica.- Ultrastructural Study
Authors: Treviño Norberto , Feria-Velasco Alfredo , de Chávez I. Ruiz 
Published: June 2020

Although erythrophagocytosis by various species of Entamoeba is a well known phenomenon this has not yet been studied in detail at the ultrastructural level. The present work deals with the description of the incorporation process of erythrocytes by trophozoites of E. histolytica. For this study, trophozoites of E. histolytica, HK-9:NIH strain cultured in axenic conditions and washed human erythrocytes were placed on a hot plate at 37°C in physiological saline solution. After 5 minutes, 2.5% glutarldehyde was added and the samples were processed according to conventional techniques for electron microscopy.Based upon light microscopy studies on living trophozoites in contact with erythrocytes, it seems that erythrophagocytosis only takes place in one pole of the parasite.
Fine Structure of Intestinal Epithelia of Earthworm
Authors: Clifford Brendan 
Published: June 2020

An ultrastructural investigation of the intestine of the earthworm, Lumbricus terrestris was undertaken as a part of a continuing study of absorptive epithelia.The earthworm gut is essentially a straight tube extending from gizzard to anus. The epithelia is an unicellular layer which can be regionally differentiated according to apical plasma membrane elaborations. The cells of the anterior 3/4 of the intestine possess microvilli and cilia (whose rootlets converge into bundles white approaching the basal plasma membrane). The cells of the dorsal typhlosole have microvilli but lack cilia while those of the posterior intestinal region possess microvilli, lack cilia and are covered by a well-defined cuticle through which the microvilli extend. The microvilli throughout the intestine (including those which extend through the posterior cuticle) are covered by a glycocalyx.
Electron Microscope Study of RNA's of Paramyxoviruses
Authors: Baum Ruchama , Seto J.T. 
Published: June 2020

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.
Geometry of the T-Even Bacteriophage Head
Authors: Gordon C. N. 
Published: June 2020

The T-even bacteriophage head is a non-isometric structure composed of more than one kind of protein. The head is assembled in a complex process which involves several products of the phage DNA, and probably the participation of the DNA itself. Two problems which are as yet unsolved are the manner in which the protein subunits are arranged in the mature phage head and the mechanism of head assembly.There are two conflicting theories regarding the geometrical shape of the head: Moody and Boy de la Tour and Kellenberger consider the head shape to be a bipyramidal pentagonal, antiprism (“prolate icosahedron“); this structure can be thought of as being derived from a head with regular icosahedral symmetry by lengthwise extension of the middle section.
An “Ultrafilter” in the Margo of Mature Bordered Pits?
Authors: Sachs I. B. , Kinney R. E. 
Published: June 2020

The micrographs illustrating this paper were obtained from never-dried springwood bordered pit-pairs of Pinus strobus L. Specimens were treated with acidified sodium chlorite in order to remove incrusting materials from the pit membrane. To prevent or reduce interfacial and surface tension forces and provide a view of bordered pit structure without postmortem changes, the specimens were further treated either by the critical point method of Weatherwax and Caulfield, a version of Anderson's method, or by a low temperature evaporation method using molecular sieve material at -40° C. to gently remove the alcohol, Arenberg, et al. For studying the pit membrane of bordered pit-pairs, neither technique seems to have an advantage, giving similar results.Light and electron microscope studies have established that structurally the bordered pit-pair membrane consists of a torus and a margo.
Mitochondrial Changes in Cholestasis
Authors: Zaki F. G. 
Published: June 2020

Alterations of liver cell mitochondria represent pathologic phenomenon of a fundamental nature. Mitochondrial anomalies have been often described in association with cholestasis. In attempt to determine whether a given pattern of mitochondrial alteration has any correlation with the cause of cholestasis, liver biopsies were examined from 38 patients showing :a. extrahepatic cholestasis due to complete or partial extrahepatic biliary obstruction (8 cases proven at operation)b. intrahepatic cholestasis due to drugs (9 cases), viral hepatitis (6 cases) and alcoholic cirrhosis (15 cases).Mitochondria exhibiting ultrastructural changes due to aging or to the ‘wear and teart’ processes were not considered. In this study, the only profound and most prominent mitochondrial deformation was reported on basis of their common occurrence in randomly examined sections.
Human Adenovirus Uptake by Preirnplantation Mouse Embryos
Authors: Chase D. G. , Winters W. , Piko L. 
Published: June 2020

Although the outlines of human adenovirus entry and uncoating in HeLa cells has been clarified in recent electron microscope studies, several details remain unclear or controversial. Furthermore, morphological features of early interactions of human adenovirus with non-permissive mouse cells have not been extensively documented. In the course of studies on the effects of human adenoviruses type 5 (AD-5) and type 12 on cultured preimplantation mouse embryos we have examined virus attachment, entry and uncoating. Here we present the ultrastructural findings for AD-5.AD-5 was grown in HeLa cells and purified by successive velocity gradient and equilibrium density gradient centrifugations in CsCl. After dialysis against PBS, virus was sedimented and resuspended in embryo culture medium. Embryos were placed in culture at the 2-cell stage in Brinster's medium.
Ferritin-Tagging for Group Cross Reactions of Rinderpest, Canine Distemper, and Measles Viruses
Authors: Breese Sydney S. , DeBoer Carl J. 
Published: June 2020

The three viruses, rinderpest, canine distemper, and measles are all antigenically related. The viruses in this experiment were all grown in a common host cell, Vero (green monkey kidney), and then each tagged with ferritin conjugated antibody against each. This procedure provided positive identification of each of the virus structures in a heterologous cell system, which did not show non-specific reactions.The Kabete “O” strain of rinderpest was received from Dr. W. Plowright, East African Veterinary Research Organization, Maguga, Kenya. The canine distemper virus was the Lederle strain (egg adapted) provided by Dr. J.A. Gourlay, National Animal Disease Laboratory (NADL), Ames, Iowa. The measles virus was the Enders strain provided by Drs. Wagner and Seligman, Division of Biologic Standards (DBS), National Institutes of Health (NIH), Bethesda, Maryland.
Particles in the Serum and Liver of a Chimpanzee Infected with Hepatitis Type B
Authors: McGrath Philip P. , Barker Lewellys F. , Chisari Francis V. , Kirschstein Ruth L. 
Published: June 2020

Blumberg et al. discovered a new antigen in the blood of an Australian aborigine and subsequently this antigen was found to be associated with viral hepatitis type B (serum hepatitis). Serologic and biochemical changes characteristic of viral hepatitis were induced in chimpanzees by inoculation of human serum containing the Hepatitis B Antigen (HB Ag). The light and electron microscopic findings were essentially the same as those of acute viral hepatitis in man. This report will describe the particles in the serum and liver of one animal from that study.One milliliter (ml) of the NIH plasma pool which had been shown to contair. HB Ag was inoculated into a 15 lb. chimpanzee.
A Revised Device for Automated Tissue Processing in Electron Microscopy
Authors: Aihara Kaoru , Saito Hiroshi , Yajima Gompachi , Suzuki Katsuya , Inoue Kiyoko , Nishikawa Hideki , Nakamura Shinichi 
Published: June 2020

This is to communicate the technical modification and improvement of the Aihara processor designated for automated tissue processing for electron microscopic histology which has been described previously. At present, in terms of the technical difficulties, the automated tissue processing is not yet widely accepted for practical application.The present hitherto reported modification of the previous device has been achieved to accommodate the main unit and synchronized thermal and humidity control units in a single frame for the simplification and trouble free operation. The entire view of the device is demonstrated in Fig(1). The basic operational principle utilized in this device is essentially identical with that of hitherto described, however, for more precised operation, tape controlled time programming system as illustrated in Fig(2) is employed.The elevation of plastic dome is activated by the motor-driven mechanism. The pre-fixation with glutaraldehyde, rinse in buffer solutions postosmification, dehydration in graded alcohols or acetones, soaking in propylene oxide or QY-1, impregnation in epoxy resin are achieved in a single programmed schedule without manual manipulation.
Immuno-Electron Microscopic Study on the Mechanism of Antibody Production inin VitroSystem
Authors: I. Suzuki , T. Takahashi 
Published: June 2020

Kamei and Moore reported the specific antibody production of P3-J cell line which has been established from ascites cells of patient with Burkitt's lymphoma, after exposure to T2phage as antigen. P3-J cell line is composed of lymphoblastoid cells and other larger cells, and has ability of immunoglobulin synthesis. The analysis of antibody production by this cell line may offer a model of that of the very complicatedin vivosystem. The present investigation, utilizing the procedure for visualizing intracellular anfibody against horseradish peroxidase, was initiated to know the sequence of cellular events in the P3-J cell line during the production of an antibody after exposure to the antigen.A human lymphoblastoid cell line, P3-J, was used the present study. This cell line was originally established from ascites cells of patient with Burkitt's lymphoma.
Electron Microscopy of Canine Hepatic Cells in 2-Ethyl-2-Phenyl Butyramideinduced Porphyria
Authors: Zaki F. G. , Keysser C. H. 
Published: June 2020

Previous studies in this department with 2-ethyl-2-phenyl butyramide (EPB) have shown that this compound is extremely hepatotoxic in dogs and produces precipitation of yellowish-brown material in hepatocytes and bile canaliculi. Continuous investigations have established that the hepatic injury induced by EPB is porphyria.EPB was administered orally in capsules to male dogs and to both pregnant and non-pregnant female dogs for periods ranging from 10 to 42 days at a total daily dose level of 50 mg/kg/day.Light microscopic examination of sections of liver from adult dogs as well as newborn animals from treated mothers showed prominent yellowish-brown deposits in the hepatocytes, bile canaliculi, and sinusoids. These deposits closely resembled the bile plugs commonly seen in cholestasis. However, histochemical tests showed that these “pseudo” plugs contained neither conjugated nor unconjugated bilirubin.Samples of serum, urine, and bile, as well as slices of liver of dogs given EPB, showed red fluorescence when subjected to ultra-violet light, indicating the presence of porphyrin.
Role of Sub-Micron Particles in Air Pollution
Authors: Bush A. F. , Burke J. P. , Bowler E. S. C. 
Published: June 2020

In the decade ahead greater attention to sub-micron particulates in air pollution will most certainly occur. The importance of the electron microscope and support equipment will be invaluable. Airborne particles in the sub-micron size range, detectable only by electronmicroscopy, have been studied at the Air Pollution Research Facility at the School of Engineering and Applied Science at UCLA. Samples were taken of ambient air daily for several months in the downtown area of Los Angeles. From the study it was clear that a substantial difference in the number of sub-micron particles existed when comparing a clear day with a smoggy day. The magnitude was ten fold (0.07 billion particles/cubic foot to 0.7 billion/cubic foot). The geometric mean particle size was approximately 0.03 microns.Samples were also collected from a variety of specific sources. Most of these were associated with the combustion of fuel: coal, oil, natural gas, gasoline, diesel fuel, wood, and industrial and domestic wastes.
Fine Structural Changes Produced by Benzo(A)Pyrene on Human Respiratory Epithelium in Organ Culture
Authors: Dirksen Ellen Roter , Timothy Crocker T. 
Published: June 2020

Earlier studies in this laboratory demonstrated that extensive ultrastructural alterations could be produced as a response to chemical carcinogens in the ciliated columnar epithelium of suckling rat trachea maintained in culture. More recently benzo(a)pyrene (BaP) has also been shown to induce similar pleomorphic fine-structural lesions in hamster respiratory tissues. It was therefore of considerable interest to extend these observations in order to compare these animal model systems of inhalation carcinogenesis with similar studies on human tissues.Tracheas from four to five month-old fetuses were cultured for 14 days in medium containing 10 μg/ml of BaP dissolved in 1% dimethylsulfoxide (DMSO), while the control tissues were exposed to a similar concentration of DMSO. At this age the tracheal epithelium has achieved a level of cellular and subcellular differentiation closely comparable to that of the adult.After 14 days in culture the epithelium of the control tracheal explants has maintained its normal architecture.
Thin Metal Film For Electron Microscopic Study of Air Pollutants
Authors: Sakabe H. , Homma K. 
Published: June 2020

Waller and others demonstrated the electron micrographs of particles in town air collected on the formvar-coated cover glass. We devised a thin metal film method for electron microscopic study of air pollutants. Since some of the particles collected on thin metal film react on the metal, we can get more information about particles than in case of ordinary membrane. In other words, by thin metal film method, we can see under electron microscope results of chemical reaction between pollutants and metal.Collodion-coated specimen grid is placed on a cover glass and covered with fume evaporated from metal heated in tungsten wire coil in vacuum evaporator. The thickness of this metal film on collodion membrane is assumed to be about 50-100Å. As for metals, Au, Cu, Ag, Fe, Zn and others are used. The same pollutant gives different figures on different metal films.
Scanning Electron Microscope Induced Cathodoluminescence
Authors: Falk Richard H. 
Published: June 2020

Luminescence is a process in which radiation is emitted by molecules or atoms that have been excited by the absorption of radiation. Accelerated electrons have energies very much greater than the quantized levels of atoms and molecules and in passing through a substance, detach bound electrons. A plasma (ion-electron gas) is formed and as recombinations occur, light quanta are emitted. Thus, if one uses accelerated electrons as the source of exciting radiation, observations of cathodoluminescence (CL) may often be made.Much of the energy absorbed is lost in processes other than luminescence. Losses by internal conversions may occur which involve intersystem crossing from the excited singlet state to the triplet state (phosphorescence or heat) or through predissociation (disruption of chemical bonds in the compound). Energy loss by external conversion (quenching) may also occur through collisions with other molecules (radiationless energy transfer or heat).
Current Developments in Cryo-Ultramicrotomy
Authors: Algy Persson K.G. 
Published: June 2020

review of cryo-ultramicrotomy covers a rather short period. This preparation method was accepted first at the end of the 1950's and began to be used in the 1960's for technical material such as rubber. It was applicable to elastomers because of their properties at temperatures below glass transition point. Apart from trials in the beginning of the 1950's, the use of cryo-ultramicrotomy for biological material did not really start until the middle of the 1960's.The instruments for cryo-ultramicrotomy can be divided into three categories, in the order of their complexity, as follows:1. Cryo-specimen holders, which keep a small part at the end of the specimen arm at low temperature. They give little or no protection to the specimen against frost, the temperature control is difficult and they are rarely combined with cryo-knife holders. Their application is limited to elastomers.
A Field Emission Gun
Authors: Worsham R. E. , Mann J. E. , Richardson E. G. 
Published: June 2020

On theoretical grounds, Welton has shown that with a conventional microscopy Column in which the illuminating wave has a transverse coherence length of ∼1000Å, the micrographs may be processed to extract information fixing the locations of heavy atoms to ∼ 1Å. The method, which involves linear filtering of the Fourier transform and re-transformation to get the corrected image has been illustrated using simulated micrographs. The illumination system shown here in schematic form is part of a so-called “high-coherence” column designed for this method. It consists of a 150-kV field emission gun and a single condenser lens. The remainder of the column, not shown, uses a superconducting objective lens with normal intermediate and projector lens.The objective operates as a second-zone lens. Therefore a ray bundle entering the lens field parallel to the axis would arrive at the specimen parallel to the axis but reduced in diameter by a factor of 1.41, in this case.
A Comparison of Oxides Grown in Stationary and Moderate Velocity Gas Streams
Authors: Dils R. R. 
Published: June 2020

The gas dynamics of many industrial environments induce small fluctuations in the heat flow between the environment and exposed metal surfaces. Temperature fluctuations of the protective metal oxide and metal near the surface of the material result, and, due to the difference in the thermal expansion coefficients of the strongly bound oxide and the metal substrate, shear stress intensities are generated along the weak interface bonds between the metal and the oxide. The oscillatory shear stress intensities fatigue the interface, causing an increase in the rate of oxidation of the material. An example of the effect of the small interface temperature fluctuations on the morphology of the protective oxide is presented in this paper.Aluminized MarM-200 nickel-base superalloy specimens were oxidized at an average temperature of 2100°F in a stationary gas and in moderate velocity gas streams which induced different temperature waveforms at the interface.
Recent Results in High Resolution Microscopy with Special Apertures
Authors: Thon P. , Willasch D. 
Published: June 2020

In bright field high resolution electron microscopy phase plates of varying thickness have been proposed to achieve better phase contrast transfer properties of objective lenses. It was possible to produce these elements by use of a microrecording device and to demonstrate their application in high resolution microscopy. But in order to obtain more favourable results a way of finding the correct phase profile had to be found.Fig. 1 shows an improved phase plate and its profile. To test the transfer properties of this plate it was used for taking focal series on thin carbon foils. Fig. 2 shows such micrographs together with their light optical Fourier transforms at different defocus values. A broad continuous frequency band is transmitted approximately at the defocus value for which the plate was calculated. It is interrupted only by a small annular zone of reduced transfer due to the edge of the central hole of the phase plate.