bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural effects of combined hematoporphyrin derivative (HpD) and phototherapy on bladder transitional cell carcinoma
Authors: Shulok J. R. , Klaunig J. E. , Selman S. H. , Schafer P. , Goldblatt P. J. 
Published: June 2020

Hematoporphyrin derivative (HpD) is a mixture of porphyrins possessing tumor localizing and photosensitizing properties. This compound has been examined in both animal models and in human clinical trials for the treatment of a variety of neoplasms. Although the treatment appears effective, many questions remain concerning the mechanism of action of hematoporphyrin derivative. This study examined the ultrastructural effects of combined HpD and phototherapy on a transplanted rat transitional cell tumor.Four week old Fischer F-344 rats were subcutaneously injected with 1x106 viable AY27 cells (a rat bladder transitional cell carcinoma line). The resulting tumors were grown to 1 cm3 in size at which time each rat was given a single tail vein injection of 10 ug HpD/gram body weight. After 24 hrs. tumors were irradiated with light (630 nm; 200 mW/cm3) for 30 min. Treated tumors were sampled at 0, 0.5, 1, 4, and 24 hrs. post-phototherapy and processed for transmission electron microscopy. Additional rats with tumors were treated with either HpD only, light only, or nothing.
Morphometry in pathology
Authors: Dardick Irving 
Published: June 2020

As medical sciences strive to make observations more precise, pathologists are becoming interested in objective histological and cytological evaluation. Morphometry is one procedure for deriving objective data, and measurements and statistical analysis of cell, nuclear or tissue parameters can be made with relatively inexpensive equipment. We are currently using an Apple II Plus microcomputer, a digitizing tablet (GTCO Corporation, Rockville, Md.) and a morphometric analysis system software diskette (Atlantis Scientific Systems Group Inc., Ottawa, Canada).Increasing numbers of reports of morphometric studies in pathology are appearing in the literature. Comparative analysis of nuclear shape of lymphocytes in mycosis fungoides and chronic dermatoses and measurements of microvillous length in mesotheliomas and adenocarcinomas show the value of this technique.
Functional reconstitution of lens junction proteins into proteoliposomes
Authors: Nikaido Hiroshi , Rosenberg Emiko Y. 
Published: June 2020

Many cells in animal tissues are connected together through “communicative junctions”, such as gap junctions, and protein oligomers (sometimes called connexons) with an apparent central channel have been isolated from the regions of liver plasma membrane enriched in such junctions. Although ingenious approaches such as dye injections have been used to characterize the properties of the channel, to our knowledge there has been no report of direct reconstitution studies of the type widely used with bacterial channelforming protein, porin, or with its analog from the mitochondrial outer membrane, mitochondrial porin.More recently, membranes from lens fiber have been studied intensively, because they contain a large abundance of one protein, which appears to be the subunit of intercellular junctions. However, the subunits of the lens junction is different from those of liver gap junctions in its molecular weight, peptide map pattern, and immunological specificity.
Ultrastructure of acute lymphoblastic leukemia in ovine induced by inoculation of bovine leukemia virus.
Authors: Al-Bagdadi F. , Seger C. , Titkemeyer C. 
Published: June 2020

The malignant transformation of normal cells by leukemia viruses is the subject of much current interest. It has been reported that subcutaneous inoculation or oral administation of blood from leukotic cows into sheep caused lymphoproliterative malignant tumors. The present study was undertaken to define the ultrastructure of ovine lymphocytes with lymphosarcoma induced by inoculation of bovine leukemic virus (BLV). It was also anticipated that electron microscopy would give information concerning the possible etiologic factors involved in ovine lymphosarcoma.Twenty Louisiana native lambs were divided into three groups. The first group, six controls, were inoculated with 1 ml of tris buffer, 0.9 ml via the jugular vein and 0.1 ml was inoculated intradermally at the prescapular area. The second group, of seven, were inoculated with BLV culture at early passage, 0.9 ml via the jugular vein and 0.1 ml intradermally at the prescapular area. The third group, of seven was inoculated with BLV culture at late passage, 0.9 ml via the jugular vein and 0.1 ml intradermally at the prescapular area.
The keratinized layers as an ideal region for TEM localization of microorganisms in bovine dermatitis
Authors: Isitor G.N. 
Published: June 2020

Bovine dermatitis of bacterial and viral involvement are of common occurrence in different parts of the world. The notable bovine dermatitis of both categories are dermatophilosis, lumpy skin disease and pyoderma. In terms of overall prevalence and severity, dermatophilosis is among the topmost ranking of all bovine dermatitis. It is usually a chronic dermatitis affecting most domesticated animals and man all over the world, especially in humid topical regions.The role of the outermost keratinized layers in common bovine dermatitis, such as dermatophilosis, appear not to be fully appreciated in view of the usual assumption that the keratinized layers are solely composed of dead tissue elements. It is therefore a common practice to discard the keratinized layers during processing of skin biopsy lesions. The result is that the associated micro-organisms are hardly localized or non significantly isolated. The present report furnishes evidence indicating that the keratinized layers serve as an ideal region for the activities of micro-organisms associated with two types of bovine dermatitis clinically resembling dermatophilosis.
Tissue reaction to and biodegradation of two different microcapsule formulations: DLPLA and DLPLGA
Authors: Visscher G. E. , Robison R. L. , Argentieri G. J. 
Published: June 2020

It was our goal to characterize the tissue response to and biodegradation of microcapsules of lypressin composed of two different polymers. Microcapsules of lypressin were made with the polymer 50:50 poly (DL-lactide-co-glycolide) DLPLGA and poly (D, L-lactide) DLPLA. The work which is presented here compares the in vivo characteristics of these microcapsules as drug delivery systems.For the study using DLPLGA, 14 groups of male rats were administered, as an intramuscular injection (gastrocnemius), microencapsulated lypressin (1%). Injections of microcapsules were examined through Day 63 of the experiment. In the second study using DLPLA, 27 male rats were injected with microcapsules of lypressin (0.4%) and examined at 30 day intervals through 420 days post injection. Light microscopy was used to characterize the tissue reaction to the injected microcapsules.
Ultrastructure of bronchopulmonary lavage cells from bovines administered 3-methylindole: II. 24 hours post-treatment
Authors: Singh Amreek , McLaren Judith M. , Atwal Onkar S. , Eyre Peter 
Published: June 2020

Introduction3-methylindole (MI), a rumen metabolite of the amino acid L-tryptophan, has been shown to produce bovine pulmonary edema and emphysema. The airways contain free and exfoliated cells. A morphologic analysis of these cells may complement the understanding of the mechanism of lung edema. Ultrastructure of the bronchopulmonary lavage (BL) cells 24 h following MI oral administration to calves is described in this experiment. The 12 hours post-treatment results were described earlier.Materials and MethodsTwo Holstein-Friesian calves were each administered an oral dose of 0.2 g MI/Kg body weight and another two calves served as controls. The animals were euthanized with sodium pentabarbitol 24 h after receiving the compound. The lungs and trachea were removed and 0.1 M sodium phosphate buffered saline was infused into the lungs through the trachea. Glutaraldehyde fixative was added to the recovered BL fluid so as to form a 1% solution. The fluid was centrifuged and the resulting cell pellet was suspended in the buffer. The procedures were repeated on the suspension; the pellet was post-fixed in osmium tetroxide and was processed by conventional methods of section preparations for TEM examination. Lung samples from caudal lobes were fixed in 1.5% glutaraldehyde to obtain tissue sections for TEM.Results and DiscussionPulmonary alveolar macrophages (AM), neutrophils, ciliated epithelial cells, globule leukocytes and plasma cells were recovered from the BL fluid of the control and Mi-administered calves. Ciliated cells and globule leukocytes could not be harvested from the controls. The AM obtained from the treated calves (Fig. 1) in comparison with similar cells from the controls were larger, and contained large membrane-limited inclusions (phagolysosomes). There was a remarkable similarity between the lavaged AM and the AM studied in thin sections of lung (cf. Fig. 1 and Fig. 2). The neutrophil was the second most abundant cell type retrieved from the lavage fluid from the calves of control or treated group. Except for scanty pseudopodia in the neutrophils obtained from the Mi-receiving calves, the cells appeared unaltered (Fig. 3). Ciliated cells were abundant in the BL fluid of Mi-ingesting calves. A heterogeneous collection of vesicles filled the ciliated cell cytoplasm (Fig. 3). Globule leukocytes were commonly observed among BL cells of treated calves. The globule leukocytes were ca. 15 μm in diameter and contained round or elliptical nuclei with conspicuous nucleoli. The cytoplasmic granules, which are a prominent feature of globule leukocytes, were electron-opaque and had a variable diameter (0.5-3.0 μm). A one-line account of globule leukocytes in the bronchi of steers administered MI has appeared. Plasma cells were rare. Ultrastructure of BL cells is compatible with their response to chemical insult by MI.
Ultrastructural aspects of the cell envelope of Legionella
Authors: Sun C.N. , Morgan P. , Bowen W.R. 
Published: June 2020

The causal agents of Legionnaires’ Disease and related respiratory ailments in humans are gram-negative rod-shaped bacterial species belonging to the newly recognized genus, Legionella. During a comparative study of the ultrastructural organization of the cell boundary in several species, additional information regarding the presence and nature of various appendages of the cell envelope in these bacteria was observed.Cultures of L. pneumophils (including several serogroups) and L. micdadei were grown on charcoal yeast extract agar with increased humidity at 37°C. Samples were removed after 5 days of growth and immediately fixed in either glutaraldehyde/ruthenium red (GA/RR) followed by osmium tetroxide/ruthenium red (OSO4/RR) or glutaraldehyde/tannic acid (GA/TA) followed by osmium tetroxide. Thin sections were stained with uranyl acetate and lead citrate.
Correlated scanning and transmission electron microscopy of Naegleria fowleri amoebastomes
Authors: Cole T. B. , Bruner R.A. , John D.T. 
Published: June 2020

Naegleria fowleri is a free-living amoeboflagellate that is the causative agent of primary amoebic meningoencephalitis (PAM) in humans and is also cytopathogenic for established mammalian cell cultures. Scanning electron microscopy has shown that the focal ingestion of cultured cells is mediated by a sucker-like structure found on this amoeba. Another report also describes well-organized sucker-like structures called amoebastomes. In this report, we will correlate scanning (SEM) and transmission electron microscopy (TEM) to demonstrate the morphology and the application of the amoebastome of the invasive N. fowleri trophozoite.Isolates of N. fowleri amoebae were grown at 30°C with Nelson medium in standard round 35x10mm plastic petri dishes. Cultured yeast cells were washed in amoeba saline and added to the amoebic cultures 3 hr prior to fixation. At 72 hr of culture age, the amoebic cultures with the added live yeast cells, were carefully rinsed with amoeba saline and fixed for 1 hr at room temperature (23°C).
Tufts of modified microvilli of tapeworm inserted into liver tissue
Authors: Rikihisa Y. , Lin Y. C. 
Published: June 2020

The surface of the tapeworm is covered with special microvilli. Since the tapeworm lacks both alimentary tract and respiratory system throughout its life history, the tegument (and its microvilli) is the major organ through which absorption of nutrients and oxygen occurs. The tegument is also extremely important for excretion and secretion, and it is the site of the recognition and reaction to the parasite by the host immune system. All of these conditions are also related to any pathologic consequences of the infection.In this study, the early stage of experimental infection of rat liver with Taenia taeniaeformis was examined by transmission electron microscopy (TEM). Tapeworm oncospheres hatch in the rat intestine, penetrate the intestinal wall and finally lodge in the liver tissue. In the liver cyst, a larva grows in its bladder whose surface is directly apposed to the liver cells, whereas the scolex is invaginated into the sac of the bladder and protected from direct exposure to host tissue.
The formation of Ni-silicide phases on dislocations and twins in Si
Authors: Vanderwalker D. M. 
Published: June 2020

The Ni-silicide cloudlike phases which form near dislocations and the edges of twin plates in Si can potentially be used as microwires. In this study, a Si specimen was compressed along a [231] axis and cooled under a high stress by the method of Wessel and Alexander. A layer of Ni was then evaporated on a slice taken parallel to the (111) surface before ageing at 260°C. The transmission electron microscopy was performed on the JEM 200CX.TEM examinations of the structure show there are hexagonal dislocation loops and twin boundaries. The dislocation segments are confined to <110> directions. The precipitation is heterogeneous. There are two phases present, a cloudlike phase and a small spherical phase. Both phases are found to nucleate near the edges of the twin plate. The cloudlike phase is observed along the edge of the twin plate shown in figure 1.
The internal structure of medullated wool
Authors: Barish Leo 
Published: June 2020

Although most of the wool used today consists of fine, unmedullated down-type fibers, a great deal of coarse wool is used for carpets, tweeds, industrial fabrics, etc. Besides the obvious diameter difference, coarse wool fibers are often medullated.Medullation may be easily observed using bright field light microscopy. Fig. 1A shows a typical fine diameter nonmedullated wool fiber, Fig. IB illustrates a coarse fiber with a large medulla. The opacity of the medulla is due to the inability of the mounting media to penetrate to the center of the fiber leaving air pockets. Fig. 1C shows an even thicker fiber with a very large medulla and with very thin skin. This type of wool is called “Kemp”, is shed annually or more often, and corresponds to guard hair in fur-bearing animals.
High resolution at low voltage: The SEM philosopher's stone?
Authors: Boyes E. D. 
Published: June 2020

A new type of scanning electron microscope (SEM) has been designed to produce nanometre-level high resolution secondary electron images of the surfaces of uncoated non-conducting specimens such as structural ceramics, cement (Fig.1), supported catalyst particles (Fig.2), fine scale metallic features (Fig.3) including radiation damage, and eventually also biological material. Clean low voltage systems also look promising for microanalysis of surface layers e.g. Fig.4.Very useful 5-20nm resolution images of surfaces are obtained with a conventional electron microscope operated at 25-100kV (Figs.2,3) but at these high accelerating voltages the secondary electron yield of most materials is very low, typically < 0.1, and there are therefore severe surface charging problems with non-conducting regions of specimens, the images of which are consequently of poor quality.
Thermal field emission for low-voltage SEM
Authors: Orloff J. 
Published: June 2020

Low voltage SEM is an increasingly important technique for examining specimens which can be damaged by high energy electrons or which are insulators. It is particularly useful for the study of semiconductor devices and a number of specialized methods have been developed. These include voltage contrast SEM, e-beam induced conductivity, stroboscopic SEM, inspection and line width measurement. Low energy is necessary because many circuit components, especially MOS devices are easily damaged. Moreover, insulating components of circuits, including passivation layers, dictate beam energies ≲ 1 keV in order to avoid electrical charging.The current density and brightness of a thermionic cathode are proportional to the voltage of the cathode with respect to the specimen; consequently the current which can be focused into a given beam diameter decreases with beam energy. In contrast, the current density and brightness of a field emission cathode depend on the electric field at the emitter surface, so that by the appropriate choice of gun geometry, high brightness can be attained at low beam energy.
Lithography with low-energy electrons
Authors: Newman T. H. , Pease R. F. W. , Polasko K. J. , Yau Y. W. 
Published: June 2020

Two prominent problems of electron beam lithography are slow throughput and proximity effects. The former arises from the serial nature of the exposure process; the current available in a beam of given resolution is limited by electron optical considerations and the resist sensitivity is limited by material considerations such that a dose of 1 μC/cm2 at 20 kV is required for the most sensitive resist and ten times that dose if high resolution is required.Proximity effects are caused by electrons scattered through lateral distances greater than the resolution of the pattern; a 20 keV electron in silicon has a range of about 3 μm whereas feature sizes are often less than 1 μm. Lowering the energy of the exposing electrons to, say, 2 keV would lower the electron range to less than 0.1 μm in silicon and thus effectively eliminate proximity effects as far as semiconductor circuit fabrication is concerned.
The disordering process in an Ll2 ordered alloy
Authors: Horton J. A. , DasGupta A. , Liu C. T. 
Published: June 2020

Ordered intermetallic alloys potentially have good high temperature mechanical properties which often are obtained by macroalloying. Since service temperatures may be near the critical ordering temperature, Tc, it is important to understand the disordering processes. The disordering mechanism in an alloy of 52.5 at. % Ni—22.5 Fe—14.5 V—10 Al—0.5 Ti [which can be expressed as (Ni70Fe30)3(V58Al40Ti2)], will be presented here. The aluminum was added to increase Tc from 750 to 975°C and stabilize the Ll2 structure.All specimens were first fully ordered by a heat treatment consisting of 30 min at 1000°C, 1 d at 700°C and 2 d at 600°C which results in a “swirl” pattern of antiphase boundaries (APB) similar to Fig. 1. Specimens were then heat-treated for 24 h at temperatures from 600 to 950°C in 50°C increments and water quenched.
Electron probe analysis, x-ray mapping and electron energy loss spectroscopy of elemental distribution inEscherichia coliB
Authors: Chang Chung-Fu , Shuman Henry , Somlyo Andrew P. 
Published: June 2020

The ability of bacteria to concentrate minerals is well known, but little is known about the subcellular distribution of ions. Electron probe microanalysis, X-ray mapping and electron energy loss spectroscopy of ultrathin cryosections are particularly suitable for determining composition at the ultrastructural level in cells, including bacterial spores. In the present study, we report preliminary experiments with these methods on elemental concentrations and distribution in E. coli B, including differences in the calcium content between dividing and non-dividing cells.E. coli B were grown in the presence of 1% tryptone (DIFCO), 0.2% glucose and 0.1M NaCl. The cells were harvested at a concentration of ∽3x108cell/ml (in the late log phase). Cells were washed in nominallv ion-free solutions and then frozen, in the presence of 10% PVP, in supercooled Freon 22 at -164°C. The specimens were freeze-dried and cryosectloned as described previously. Analyses were performed on a Gatan LN2cold specimen holder, at a temperature of -101°C. A bright-field image of the cryosectioned E. coli is shown in Fig. 1.
The theory of Gaussian deconvolution applied to EDS spectra
Authors: Hashemi Ebrahim 
Published: June 2020

A limiting factor in EDS analysis has been that the resolution of Si(Li) detectors has remained above 130 eV (at 5.9 keV). However, elemental peaks separated by only a few eV are not uncommon in x-ray spectra. For such cases peak area extraction by simple integration or peak stripping can result in large errors. Peak overlap factors are useful in some applications, but the large data base required makes general application difficult.Although the library least squares method is generally applicable, it requires many pure element or at least nonoverlapping standards. Because of the time-variance of peak shift and resolution, standard data must either be acquired at the same time as unknown data, or the electronics and software must be constantly recalibrated.
Analytical electron microscopy of a selective oxide scale formed on 20%Cr/25%Ni/niobium stabilized stainless steel
Authors: Bennett M.J. , Desport J.A. , Labun P.A. 
Published: June 2020

In the United Kingdon commercial advanced gas cooled nuclear power plants the fuel cladding is a 20%Cr/25%Ni/0.7%Mn/0.7%Si/Nb stabilised (20/25/Nb) austenitic stainless steel and the coolant is CO2 based. Protection of the 20/25/Nb steel surfaces can be enhanced by selective oxidation, which ensures that a Cr-rich oxide scale covers the steel surface. The selective oxidation procedure developed was compatible with the required metallurgical annealing treatment and consisted of a lh heat treatment at 930°C in 50:1 H2/H2O. Weight gain measurements indicated that the average scale thickness was 0.5 micron.Electron transparent transverse specimens of selectively oxidised 20/25/Nb steel were produced and the microstructure and chemical composition of the selective oxide scale was investigated by AEM techniques.
A three-dimensional reconstruction of the complex flagellar filament of Rhizobiwn lupini
Authors: Trachtenberg S. , Aizawa Shin-ichi , DeRosier D. J. 
Published: June 2020

The bacterial flagellum is composed of a basal body (the putative motor), a hook (the putative universal coupling), and a helical filament (the propellor). Based on their distinctive morphologies in the electron microscope, there are two different types of flagella: the plain flagellum and the complex flagellum. Most bacteria have plain flagella. Complex flagella are found in only a few species of bacteria: Rhizobium lupini, Rhizobium meliloti and Pseudomonas rhodos, and are associated with motility in a viscous medium.The most prominent feature of the complex flagellum is what seems to be an outer sheath consisting of a three-stranded helical winding (Fig. 1), which is absent from plain filaments (Fig. 2, Salmonella typhimurium). The sheath, however, does not arise from the presence of an additional subunit since the complex filament (like the plain flagellum) is made from a single species of protein, flagellin.