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  • Electron microscopy  (73)
  • NDE  (39)
  • Springer  (112)
  • American Physical Society
  • Annual Reviews
  • Springer Nature
  • 1980-1984  (112)
  • 1960-1964
  • 1935-1939
  • 1982  (46)
  • 1980  (66)
Collection
Keywords
Publisher
  • Springer  (112)
  • American Physical Society
  • Annual Reviews
  • Springer Nature
  • Wiley-Blackwell  (1)
Years
  • 1980-1984  (112)
  • 1960-1964
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Heat of fusion and lamellar structure of polyethylene single crystal mats (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 564-569 
    Details
    ISSN: 1435-1536
    Keywords: lin. Polyethylene ; Single crystals ; Heat of Fusion ; DSC ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Recently published results for solution crystallized PE single crystals have shown, that the experimental heat of fusionΔH * is higher, if the solvent is exchanged to silicon oil (oil suspension samples) as compared with dried mats. This has been interpreted by the collapse of the original hollow pyramids during drying, inducing lateral defects within the lamellae. The present investigation does not confirm this unexpected result.ΔH * of dried mats (T c 66 to 91 °C) and of the corresponding oil suspension samples agree within the rather small limits of experimental error. The crystallinities as derived fromΔH *, density or WAXS are in excellent agreement. SEM micrographs of cold fractured dried mats show their spongy macromorphology, but TEM micrographs of stained ultra-thin sections reveal the lamellar morphology of the walls, consisting of curved lamellae and stacked hollow pyramides. If a dried mat is sintered at room temperature, a dense transparent film is obtained with a rather regular stacked morphology of large flat lamellae.ΔH * of these films agrees with that of the original mat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422587
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for inhibition of chitin synthesis by nikkomycin (1982)
    Springer
    Development genes and evolution 191 (1982), S. 205-207 
    Details
    ISSN: 1432-041X
    Keywords: Chitin inhibition ; Nikkomycin ; Cuticle ; Electron microscopy ; Epilachna varivestis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleoside antibiotic nikkomycin has proved to be an effective inhibitor of chitin synthesis in the Mexican bean beetleEpilachna varivestis. Ultrastructural investigations show defects in the procuticular area after nikkomycin application which suggest the complete absence of chitin. A cuticle like this is inflexible and too brittle to satisfy its normal function as an exoskeleton. The individuals are not able to free themselves from the exuvia and finally die. Therefore nikkomycin seems to be a potential insecticide with high specifity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848337
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  • 3
    Electronic Resource
    Electronic Resource
    A scanning electron microscopic investigation of in vitro osteogenesis (1980)
    Springer
    Calcified tissue international 30 (1980), S. 43-50 
    Details
    ISSN: 1432-0827
    Keywords: Osteogenesis ; In vitro ; Electron microscopy ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick limb mesenchymal cells differentiate into muscle, cartilage, fibrous, and bone tissue. Previous reports show that when stage 24 limb mesenchymal cells are cultured in vitro, chondrocytes, myocytes, fibrocytes, and osteoblasts can be identified on the basis of morphological and biochemical parameters. The study reported here demonstrates that phenotypic expression in culture seems to be dependent on the initial plating density, Scanning electron microscopic observations indicate that when stage 24 limb mesenchymal cells are initially seeded at high densities (5 × 106 cells per 35 mm culture dish), mounds of cells appear in culture. These mounds represent cartilage nodules composed of a fine fibrous matrix and chondrocytes, surrounded by a loose fibrous connective tissue matrix. Cultures initially plated at intermediate densities (2.0–2.5 × 106 cells/35 mm culture dish) produce a flattened layer of fibrocytes overlying a matrix of collagen fibers and calcium phosphate deposits as determined by electron-microprobe analysis; these observations are indicative of osteoblast expression. Cells seeded at this intermediate density appear larger and possess greater surface area than cells seeded at high density. It is suggested that conditions that permit such increased cell surface area coupled with a relative compaction due to cell crowding may provide conditions permissive for osteogenesis. Based on morphological criteria, it appears that chick limb mesenchymal cell osteogenesis in vitro is not associated with chondrogenesis but represents a separate route of phenotypic expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408605
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  • 4
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    Fine structure of fetal rat calvarium; provisional identification of preosteoclasts (1980)
    Springer
    Calcified tissue international 31 (1980), S. 21-28 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407163
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  • 5
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    Effects of demineralization in an ethanolic solution of triethylammonium EDTA on solubility of bone matrix components and on ultrastructural preservation (1980)
    Springer
    Calcified tissue international 32 (1980), S. 175-179 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Bone matrix ; Bone glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A solution of triethylammonium EDTA in 80% ethanol was evaluated as a demineralizing reagent for bone in comparison with aqueous solutions of EDTA. Biochemical analysis and acrylamide gel electrophoresis of extracts of finely powdered bovine bone showed that most of the macromolecular components of the organic matrix extractable in aqueous EDTA were retained when the triethylammonium EDTA reagent was used. Ultrastructural examination of chick tibias decalcified with the reagents showed a better preservation of cellular morphology, especially the membranous components, and more uniformly distributed ground substance, though slightly less in quantity, when the aqueous reagent was used. Use of the two reagents appears to be complementary, the alkylammonium reagent being more appropriate for use in studies of the organic matrix of bone, including immunohistochemical studies of bone glycoproteins. The aqueous reagent is more appropriate for use in studies of cellular ultrastructure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408537
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  • 6
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    The ultrastructure of cell wall formation and of gamma particles during encystment of Allomyces macrogynus zoospores (1980)
    Springer
    Archives of microbiology 128 (1980), S. 179-189 
    Details
    ISSN: 1432-072X
    Keywords: Allomyces ; Zoospores ; Cell wall ; Chitin ; Gamma particle ; Encystment ; Electron microscopy ; Calcofluor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Structural changes during cell wall formation by populations of semisynchronously germinating zoospores were studied in the water mold Allomyces macrogynus. Fluorescence microscopy using Calcofluor white ST (which binds to β-1,4-linked glycans) demonstrated that Calcofluor-specific material was deposited around most cells between 2–10 min after the induction of encystment (beginning when a wall-less zoospore retracts its flagellum and rounds up). During the first 15 min of encystment there was a progressive increase in fluorescence intensity. Ultrastructural analysis of encysting cells showed that within 2–10 min after the induction of encystment small vesicles 35–70 nm diameter were present near the spore surface, and some were in the process of fusing with the plasma membrane. The fusion of vesicles with the zoospore membrane was concomitant with the appearance of electron-opaque fibrillar material outside the plasma membrane. Vesicles similar to those near the spore surface were found within the gamma (γ) particles of encysting cells. These particles had a crystalline inclusion within the electron-opaque matrix. During the period of initial cyst cell wall formation numerous vesicles appeared to arise at the crystal-matrix interface. Approximately 15–20 min was required for the cell wall to be formed. We suggest that the initial response of the zoospore to induction of encystment is the formation of a cell wall mediated by the fusion of cytoplasmic vesicles with the plasma membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406156
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  • 7
    Electronic Resource
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    Evidence for supercoiling in the DNA of bacteriophage heads (1980)
    Springer
    Archives of microbiology 126 (1980), S. 277-283 
    Details
    ISSN: 1432-072X
    Keywords: Bacteriophage ; Myxococcus ; λ ; Superooiled DNA ; Cross-linking ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA was partially released from the heads of myxococcus phages and also coliphage λ and examined by electron microscopy by a modification of the Kleinschmidt technique, in which water was used as hypophase. DNA emerged from the heads in patterns suggestive of newly relaxed supercoils. The unreleased DNA appeared to occupy discrete regions in the head. Some closed circles were released from λ heads. When NaCl solution was used as hypophase, the DNA was observed either released from the tail or from the head, in the latter case, supercoiled regions were observed. When NH4OAc solution was used as hypophase, tightly wound structures were released from λ heads; these fields also contained supercoiled circles. The presence of constrained supercoiled domains in newly released phage DNA was confirmed by observing the effects of ethidium bromide on its conformation. Treatment of phage with nitrogen mustard, a bifunctional alkylating agent, preserved supercoiled domains, even when the phage were lysed over water as hypophase. Further experiments suggested that phage inactivation by nitrogen mustard is largely due to restraint of the supercoiled, native, tertiary structure and that DNA-protein cross-linking may be involved in this reaction. The implications of these findings for the conformation of phage DNA in vivo are discussed and a new model for the winding of DNA in phage heads is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409932
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  • 8
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    Comparative studies onChlorella cell walls: Induction of protoplast formation (1982)
    Springer
    Archives of microbiology 132 (1982), S. 10-13 
    Details
    ISSN: 1432-072X
    Keywords: Calcofluor White ; Cell wall structure ; Chlorella ; Electron microscopy ; Protoplast ; Ruthenium Red
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Among 12 strains ofChlorella ellipsoidea, C. vulgaris, andC. saccharophila tested, 4 strains (1,C. ellpsoidea; 2,C. vulgaris; 1,C. saccharophila) formed osmotically labile protoplasts after treatment with mixtures of polysaccharide degrading enzymes. The relationship between enzymatical digestibility and structure or composition ofChlorella cell walls were studied by electron microscopy and staining techniques with some specific dyes. The cell wall structures of the 12Chlorella strains were grouped into three types: (1) with a trilaminar outer layer, (2) with a thin outer monolayer, and (3) without an outer layer. Protoplasts were formed only from the strains with a cell wall of Type 2. In the strains with a cell wall of Type 1, the outer layer protected the inner major microfibrillar layer against enzymatic digestion. The cell wall of Type 3 was totally resistant to the enzymes; the chemical composition of the cell wall would be somewhat different from that of other types.
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    URL: http://dx.doi.org/10.1007/BF00690809
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  • 9
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    Immunoferritin labeling of respiratory nitrate reductase in membrane vesicles of Bacillus licheniformis and Klebsiella aerogenes (1980)
    Springer
    Archives of microbiology 127 (1980), S. 39-46 
    Details
    ISSN: 1432-072X
    Keywords: Immunoferritin labeling ; Electron microscopy ; Membrane vesicles ; Nitrate reductase ; Bacillus licheniformis ; Klebsiella aerogenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The indirect immunoferritin labeling method was used to localize the membrane-bound respiratory nitrate reductase in membrane vesicles and protoplasts or spheroplasts of Bacillus licheniformis and Klebsiella aerogenes, respectively. For a comparison of the labeling of the various vesicle preparations, which differed not only in size but also in the percentage of inside-out orientation, a quantification of the results was needed to circumvent the problem of non-specifically bound ferritin. From the results the sidedness of the nitrate reductase in the cytoplasmic membrane of the abovementioned bacteria was determined as being cytoplasmic in B. licheniformis and as transmembranous in K. aerogenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414353
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  • 10
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    Chemical composition and ultrastructure of cellular and extracellular Moraxella glucidolytica lipopolysaccharides (1980)
    Springer
    Archives of microbiology 128 (1980), S. 12-18 
    Details
    ISSN: 1432-072X
    Keywords: Moraxella glucidolytica ; Electron microscopy ; Lipopolysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cellular (LPS I) and extracellular (LPS II) lipopolysaccharide were isolated from Moraxella glucidolytica cells grown on ethanol and from the culture fluid, respectively. Both LPS were toxic when injected to mice and chick embryos. These LPS contained glucose, galactose, glucosamine, galactosamine, 2-keto-3-deoxyoctonate and lipids. By permethylation studies, glucose was found to be linked (1→6) and (1→3) in LPS I and only (1→6) in LPS II. Galactose was the terminal non-reducing sugar. Branching occurred at positions 3 and 4 of galactose residues. LPS I was rich in α- and β-hydroxylauric and α-hydroxymyristic acids and LPS II contained mainly stearic and α-hydroxymyristic acids. LPS I was detoxified by mild acid and alkaline treatments. It was also dissociated by sodium deoxycholate and chromatographed on Sephadex G-75. The main fraction was reassociated by removing the surfactant by dialysis. The morphology of LPS I and LPS II was examined by electron microscopy. LPS I (original and reassociated fractions) consisted exclusively of ribbons while LPS II contained ribbons and vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422299
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  • 11
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    Ultrastructure of Ascodichaena rugosa on beech bark (1980)
    Springer
    Archives of microbiology 126 (1980), S. 87-95 
    Details
    ISSN: 1432-072X
    Keywords: Ascodichaena ; Beech bark ; Electron microscopy ; Host-fungus relationship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ascodichaena rugosa Butin is a corkinhabiting fungus, found frequently on the bark of Fagus sylvatica L. The hyphae of the fungus are distributed solely in the phellem cells, stopping their growth in the last-formed cork cell layer. The cell to cell invasion is effected by penetration hyphae, causing no extensive dissolution of the cork wall. Electron microscopical observations revealed fine structural details of the fruit bodies and of the intracellular hyphae. Of special interest were the finger-like hyaline hyphae in the last-formed layer of cork cells, which are interpreted as haustoria on the basis of the fine structure both of hyphae and host cells. This situation is considered as reflecting a parasitic relationship of Ascodichaena to beech bark. The activity of the fungus led also to the increased production of cork cells, perhaps related to the nutrient supply of the fungus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421896
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  • 12
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    Thylakoid centers: Structures associated with the cyanobacterial photosynthetic membrane system (1982)
    Springer
    Archives of microbiology 133 (1982), S. 97-99 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Thylakoid centers ; Photosynthetic membranes/thylakoids ; Membranes ; Membrane biogenesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ultrastructural study of four cyanobacteria (Anabaena cylindrica, Dermocarpa violaceae, Gleocapsa alpicola, Pleurocapsa minor) indicates the presence of previously undescribed thylakoid centers from which photosynthetic membranes (thylakoids) radiate. These peripherally located thylakoid centers are cylinders 30 nm wide by 320 nm long, consisting of globular subunits oriented in nonparallel stacked arrays. Thylakoids are attached to the outer surface of the cylinder along its longitudinal axis. Thylakoid centers appear to be functionally significant due to their structure, location and thylakoid association.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413518
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  • 13
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    Cell wall degradation ofStaphylococcus aureus by lysozyme (1982)
    Springer
    Archives of microbiology 131 (1982), S. 116-123 
    Details
    ISSN: 1432-072X
    Keywords: Cell wall ; Wall degradation ; Lysozyme ; Autolysines ; Electron microscopy ; Staphylococcus aureus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In contrast to former findings lysozyme was able to attack the cell walls ofStaphylococcus aureus under acid conditions. However, experiments with14C-labelled cell walls and ribonuclease indicated that, under these conditions, lysozyme acted less as an muralytic enzyme but more as an activator of pre-existing autolytic wall enzymes. Electron microscopic studies showed that under these acid conditions the cell walls were degraded by a new mechanism (i.e. “attack from the inside”). This attack on the cell wall started asymmetrically within the region of the cross wall and induced the formation of periodically arranged lytic sites between the cytoplasmic membrane and the cell wall proper. Subsequently, a gap between the cell wall and the cytoplasmic membrane resulted and large cell wall segments became detached and suspended in the medium. The sequence of lytic events corresponded to processes known to take place during wall regeneration and wall formation. In the final stage of lysozyme action at pH 5 no cell debris but “stabilized protoplasts” were to be seen without detectable alterations of the primary shape of the cells. At the same time long extended ribbon-like structures appeared outside the bacteria. The origin as well as the chemical nature of this material is discussed. Furthermore, immunological implications are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01053992
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  • 14
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    Stress-wave attenuation in thin structures by ultrasonic through-transmission (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 277-286 
    Details
    ISSN: 1573-4862
    Keywords: Ultrasonics ; through-transmission ; composite materials ; attenuation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The steady-state amplitude of the output of an ultrasonic through-transmission measurement is analyzed and the result is given in closed form. Provided that the product of the input and output transduction ratios, the specimen-transducer reflection coefficient, the specimen-transducer phase-shift parameter, and the material phase velocity are known, this analysis gives a means for determining the through-thickness attenuation of an individual thin sample. Multiple stress-wave reflections are taken into account, and so signal echoes do not represent a difficulty. An example is presented for a graphite fiber epoxy composite (Hercules AS/3501-6). Thus, the technique provides a direct method for continuous or intermittent monitoring of through-thickness attenuation of plate structures which may be subject to service structural degradation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571808
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  • 15
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    Quantitative use of Rayleigh waves to locate and size subsurface holes (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 55-63 
    Details
    ISSN: 1573-4862
    Keywords: ultrasonics ; Rayleigh waves ; subsurface defects ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An ultrasonic inspection method is used to obtain the circumference of a subsurface hole and the depth of the hole below the surface. A pitch-catch Rayleigh wave transducer set-up was used to launch a Rayleigh surface wave at the flaw and to capture and record the scattered waves. The frequency spectrum of the scattered waves can be used to obtain the depth of the hole. The ligament of material between the hole and the surface is sent into resonance, and this feature can be extracted from the scattered waves' frequency spectrum. The frequency is a function of the ligament length; thus the hole depth can be obtained. The circumference of the hole is found from a time of flight measurement. A Rayleigh wave is formed that travels around the hole's surface. The length of time required for the wave to travel around the hole is a measure of the circumference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566955
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  • 16
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    The influence of skin depth on crack measurement by the ac field technique (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 65-76 
    Details
    ISSN: 1573-4862
    Keywords: crack measurement ; ac field technique ; arbitrary skin depth ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A general solution is given to describe the ac field around surface-breaking cracks for arbitrary values of the ratio of skin depth δ to crack depthd. This solution allows accurate interpretation of crack depth from voltage readings taken by a Crack Microgauge instrument in cases where δ andd are comparable. It is shown to agree with asymptotic formulae obtained for the cases where δ/d is very small and very large. Provided that the probe length Δ is large compared with δ, the calculations show that a very good approximation to the crack depth may be obtained, irrespective of the ratio δ/d, by using the thin-skin asymptotic formula $$d = \frac{1}{2}\Delta (V_2 - V_1 )/V_1 $$ whereV 1 andV 2 are probe voltages registered at positions just off and across the crack, respectively. The problem is solved for a crack of infinite aspect ratio which has no opening, but it can be applied with confidence at the centerline of cracks of fairly large aspect ratio.
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    URL: http://dx.doi.org/10.1007/BF00568962
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  • 17
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    Infrared scanning thermography for a quantitative detection of cavities in a plane slab and a rectangular prism (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 99-109 
    Details
    ISSN: 1573-4862
    Keywords: thermography ; infrared scanning ; calibration ; inverse problems ; cavity detection ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An approach for treating nondestructive testing as the solution of inverse problems in mathematical physics has been used for the detection of cavities. The approach is developed based on the use of an additional boundary condition of scanned temperature on the surface to solve for the cavity geometry. For the present study, the condition at the cavity side is taken to be that of a specified temperature, and the experiment is carried out to meet this condition. Two specimens are tested in this paper, a plane slab and a rectangular prism. In both bodies the cavity is rectangular in shape. For the testing of the plane slab, the method is able to detect the cavity wall with high accuracy, whereas the cavity depth error is larger (6%). The detection of the cavity position in the rectangular prism has an error ranging from −9.7 to 7.7%. Errors in the experiment are attributed to the uncertainties in the measurements of temperature and the Biot number. The former is read off from the analog data output of the infrared scanner. The latter is not measured separately, but is computed from the scanned data and thus becomes a portion of the total nondestructive testing output. A final note is also made in this paper to relate how the presented method can be used in actual practice.
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    URL: http://dx.doi.org/10.1007/BF00568966
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  • 18
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    Analysis of ultrasonic wave scattering for characterization of defects in solids: I. Spherical inclusions and reciprocity (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 175-182 
    Details
    ISSN: 1573-4862
    Keywords: ultrasonic wave scattering ; inclusions ; reciprocity ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract This paper, as part of a series on elastic wave scattering, presents results of measurements and calculations on scattering of ultrasonic waves by a solid spherical inclusion (tungsten carbide) embedded in titanium alloy by the diffusion bonding process. Both direct scattering and mode-converted scattering angular distributions are reported for shear and compressional incident waves. The consequences upon the signals when transmitter and receiver were interchanged are explored in a reciprocity rule.
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    URL: http://dx.doi.org/10.1007/BF00566558
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  • 19
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    Defect identification and sizing by the ultrasonic satellite-pulse technique (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 263-276 
    Details
    ISSN: 1573-4862
    Keywords: Ultrasonics ; scattering ; diffraction ; defect characterization ; cracks ; voids ; pattern recognition ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Shape and size are the most important defect characteristics that need to be determined for the reliable prediction of the remaining service lifetime of a defective structure or part. The analytical and supporting experimental results presented in this paper concern a general, pattern recognition-based, ultrasonic defect identification and sizing method. The satellite-pulse technique (SPT) is based on the interpretation, in terms of defect types (shapes) and dimensions, of the separation in time of arrival between the readily detected specularly reflected pulse and its generally ignored tip-diffracted or tangentially scattered “satellite” contained in the received waveform. Calibration procedures were also developed that enable the ultrasonic examiner to read the time scale of the oscilloscope for equivalent crack depth or void diameter as appropriate.
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    URL: http://dx.doi.org/10.1007/BF00571807
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  • 20
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    The ac field around a plane crack in a metal surface when the skin depth is large (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 19-24 
    Details
    ISSN: 1573-4862
    Keywords: ac potential difference ; eddy current ; fatigue crack measurement ; skin effect equation ; large skin depth ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract This paper considers the solution of the skin-effect or Helmholtz equation, ∇2ψ=k 2ψ, for the two-dimensional flow of a uniform alternating current perturbed by a plane crack of uniform depth. Herek is the ratio of crack depthd to skin depth δ. When the skin depth is large compared with the crack depth andk f 0, the quasi-static approach to this problem ignores the terms on the right-hand side and constructs solutions from Laplace's equation which are essentially dc solutions and are correct to orderk. In this paper we consider behavior near the limit when the skin depth is large and give solutions which are correct to orderk 2. In an example we relate the results to the interpretation of readings from an ac potential difference instrument applied to the measurement of surface-breaking cracks.
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    URL: http://dx.doi.org/10.1007/BF00566951
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  • 21
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    Characterization of localized surface elastic defects by nonspecular reflection at the Rayleigh angle (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 93-98 
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    ISSN: 1573-4862
    Keywords: bounded ultrasonic beam reflectivity ; Rayleigh angle ; beam profile ; surface defects ; nonspecular reflection ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The relationships between characteristics of elastic defects and nonspecular features of bounded ultrasonic beams reflected at the Rayleigh angle from a liquid-solid interface are investigated. The results can serve as a theoretical basis for interpretation of Rayleigh angle nonspecularly reflected beam profiles as characterization of localized surface elastic defects.
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    URL: http://dx.doi.org/10.1007/BF00568965
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    On the optimum applied field for magnetic particle inspection using direct current (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 125-136 
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    ISSN: 1573-4862
    Keywords: magnetic particle inspection ; magnetic leakage fields ; finite difference method ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Experimental measurements of leakage fields from cylindrical defects were obtained in a geometry which permitted simultaneous measurement of the magnetic induction of the material. The results obtained are compared with calculations using a nonlinear finite difference method. Both the experiments and the calculations indicate that the magnitude of the leakage field continues to grow nearly in proportion with the applied field well into the saturation region of the magnetic material. The implications for magnetic particle inspection are discussed.
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    Time domain Born approximation (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 45-53 
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    ISSN: 1573-4862
    Keywords: Born approximation ; ultrasonic scattering ; NDE ; time domain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The time domain Born approximation for ultrasonic scattering from volume flaws in an elastic medium is described. Results are given both for the direct and the inverse problem. The time domain picture leads to simple intuitive formulas, which we illustrate by means of several simple examples. Particular emphasis is given to the front surface echo and its use in reconstructing the properties of the flaw.
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    Remaining fatigue life prediction in the initiation regime using SAW NDE (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 3-9 
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    ISSN: 1573-4862
    Keywords: harmonic generation ; fatigue ; microcracks ; aluminum ; surface acoustic waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Harmonic generation of surface acoustic waves (SAW) is shown to be a useful tool for the detection of the initiation of surface cracks during fatigue of high strength aluminum alloys. A model that relates the length and density of microcracks to the amplitude of a SAW harmonic signal is described, and an associated coefficient of generation efficiency for the second harmonic amplitude is derived. A correlation between experimentally measured harmonic amplitude and remaining fatigue life is then demonstrated, which allows the mean remaining fatigue lifetime to be estimated to within 5% over the last 50% of the fatigue life for an Al 7075 alloy if the cyclic stress amplitude, but not the duration of fatigue, is known.
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    URL: http://dx.doi.org/10.1007/BF00566227
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    Ultrasonic diffraction technique for characterization of fatigue cracks (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 11-19 
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    ISSN: 1573-4862
    Keywords: ultrasonic diffraction ; fatigue cracks ; crack closure ; crack surfaces ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract This paper describes an ultrasonic diffraction technique for characterizing fatigue cracks. The angular field of energy scattered from a crack tip was computed. Using the theoretically predicted and experimentally verified optimum range of angles, we measured the crack profiles by the ultrasonic diffraction technique. Ultrasonic measurements agreed very well with direct destructive measurements. In addition, fatigue crack closure was detected and information on crack surfaces was obtained.
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    URL: http://dx.doi.org/10.1007/BF00566228
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    Methods for determining the depth of near-surface defects (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 21-36 
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    ISSN: 1573-4862
    Keywords: ultrasonics ; surface defects ; defect depth ; deconvolution ; correlation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract In previous work by the authors,(1,6) it was demonstrated that the presence of near-surface defects could be detected reliably, even though the defect echo was contained within the near-surface echo. The algorithm consists of examining the variation in the composite (near-surface plus defect) response after it has been deconvolved from a near-surface response known to be defect-free. This paper presents two algorithms that have been developed subsequent to the work presented in ref. (6) for estimating thedepth of a near-surface defect, given that its presence has already been detected. One algorithm uses complex frequency domain techniques, and the other uses time domain analysis. Both procedures operate on the surface-plus-defect signal, using reference signals containing surface-only and defect-only responses. The defect signal is extracted from the composite signal. Defect depth is then computed from the time difference between the centers of the front-surface and extracted defect responses. A mean absolute depth error of 0.015 in. was obtained by applying the algorithms to experimental data containing depths from 0.020 to 0.130 in. below the near-surface.
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    Accept/reject decisions and failure prediction for structural ceramics: Application to failure from voids (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 37-52 
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    ISSN: 1573-4862
    Keywords: failure prediction ; accept/reject decisions ; ceramic materials ; ultrasonics ; fracture ; probabilistic model ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A general probabilistic method for reaching accept/reject decisions and failure prediction based on nondestructive evaluation procedures is described. The method is illustrated for ceramic materials that fail by the activation of microcracks located at void surfaces. The inspection procedure used for the analysis is the long wavelength ultrasonic method. The analysis indicates influences on the decision level and on the false-reject probability of variations in the signal-to-noise ratio and in the preexistent void population. The ultrasonic inspection is shown to exert a relatively minor influence on the false-reject probability, even for low signal-to-noise ratios, low stresses, and a widely dispersed void population, because of the intrinsic variability of the selected failure process. More encouraging results concerning the utility of NDE are anticipated to apply to other failure mechanisms in ceramics.
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    Analytical representation of transient ultrasonic phased-array near- and far-fields (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 53-66 
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    ISSN: 1573-4862
    Keywords: ultrasonic transducers ; phased array ; ultrasonic imaging ; impulse response ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The present contribution provides a method for the derivation of analytical near- and far-field expressions for the pressure step-function response of nonuniformly excited ultrasonic transducers modeled as pistons of arbitrary shape in an infinite rigid baffle. Explicit inversion of the Laplace transformed ultrasonic field using Cagniard's idea results in elementary functions or definite integrals of elementary functions, depending on the assumed nonuniform aperture distribution. The basic signal distortion is illustrated in terms of three-dimensional space-time plots of the pressure unit step-function response of a rectangular uniform aperture. The corresponding results for a phased-array transducer are also given. In addition, we investigate the pressure profile on the axis perpendicular to a uniform rectangular piston and its horizontal radiation pattern for different bandwidths of the exciting impulse.
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    Acoustic measurements of stress fields and microstructure (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 67-77 
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    ISSN: 1573-4862
    Keywords: stress fields ; microstructure ; J integral ; stress intensity factor ; harness acoustic velocity ; acoustic elasticity ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A very precise system for measuring two-dimensional velocity fields in solid samples has been used for nondestructive measurements of both externally applied and residual inhomogeneous stresses in solids,J integrals, stress intensity factors of cracks, and hardness of quenched steel. The longitudinal velocity measurement is based on precise determination of the propagation transit time through the stressed solid specimen using a small diameter, water-coupled acoutic transducer, which is scanned mechanically over the sample. Changes in velocity are then related to changes of stress in the sample by the theory of acoustoelasticity. Similar measurements show a high degree of correlation between longitudinal velocity changes and changes in microstructure in steel samples. Applications to problems of solid mechanics and material science illustrate the utility of this nondestructive measuring technique.
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    The relationship between radiating body forces and equivalent surface stresses: Analysis and application to EMAT design (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 79-85 
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    ISSN: 1573-4862
    Keywords: ultrasonic waves ; EMAT ; surface stress ; NDE ; Green's function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An analysis of the radiation from a body force shows that it is equivalent to the radiation from a series of surface stresses defined by the moments of the body force taken with respect to the depth coordinate. As the body force becomes localized near the surface, the zeroth moment of the force dominates the radiation and is often thought of as an equivalent surface stress. However, under certain conditions, this can vanish, and the other moments must be considered. It is found that, as the order of the moment of a particular force component increases, the resulting radiation patterns alternate between those characteristic of a compressive surface stress and those characteristic of a shear surface stress, which have considerably different angular variations. Results of experiments in the development of EMAT transducers for nondestructive testing that support these results are cited, and important consequences in the design of inspection systems are indicated.
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    An acoustic emission energy analysis and its use to study damage in laminated composites (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 225-233 
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    ISSN: 1573-4862
    Keywords: Acoustic emission ; energy analysis ; composite materials ; strength ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A new technique which uses the output of a true RMS voltmeter to measure the acoustic emission energy output of a transducer is presented. To demonstrate its use in a typical case, this procedure is used to measure acoustic emission energy during tensile tests on [0°/±30°/90°]s glass-epoxy laminate uniaxial and 10° off-axis tensile coupons. The test results were compared with numerical predictions of laminate response and acoustic emission energy. The experiments indicate that acoustic emission energy can be used to indicate the onset of ply and interlaminar failure.
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    Defect characterization in the short-wavelength regime (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 235-247 
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    ISSN: 1573-4862
    Keywords: Ultrasonics ; acoustic waves ; scattering ; diffraction ; defect characterization ; silicon nitride ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The scattering of acoustic waves by different types of spherical defects in a silicon nitride matrix is calculated by using Ying and Truell's scattering theory. The theoretical scattering results are interpreted using a ray tracing approach. Experiments were carried out at a high frequency (150–450 MHz) to characterize defects in silicon nitride. Time and space averaging, Wiener filtering, diffraction, and propagation loss corrections were used to remove the effect of the transducer response and propagation loss in the material from the scattered signal. Our experimental results indicate the presence of a new type of defect in silicon nitride. They give the type and size of voids, cracks, and Si inclusions in good agreement with measurements obtained after sectioning.
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    Quantitative characterization of flaws near a surface using inverse born approximation (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 183-188 
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    ISSN: 1573-4862
    Keywords: Ultrasonics ; Born inversion ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Quantitative reconstruction of volumetric flaws near a surface of an elastic solid has been carried out experimentally by analyzing the scattered ultrasonic waves. The inverse Born approximation (developed for flaws in bulk materials) was tested for the first time in the determination of the size, shape, and orientation of near-surface flaws. We have studied spherical solid inclusions at various depths below the surface. In addition we examined an approximately 2:1 prolate spheroidal inclusion which was located one major axis below the surface. The determination of the flaw's size, shape, and orientation in terms of an equivalent ellipsoid is realized by performing nonlinear least-squares iteration of the one-dimensional Born inversion results obtained at various scattering directions within a finite aperture. The reconstruction is in good agreement with the actual parameters of the flaw.
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    Probe characterization in ac field measurements of surface crack depth (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 9-17 
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    ISSN: 1573-4862
    Keywords: ac potential difference ; probe characterization ; induction effect ; slots ; fatigue crack ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract In the ac field method of crack depth measurement by the Crack Microgauge, the area of the loop formed in the probe gives rise to an induced voltage, which can introduce errors into the depth measurement. In this paper, a method for measuring the probe area is given, and the quality of the probe is thereby characterized. The underlying theory was given previously, and it is applied here to the probe characterization problem. The probe area is determined by two voltage measurements taken on an artificial rectangular flaw machined in an arbitrary metal. By measurements on several such specimens with the same probe, it is confirmed that the area so obtained is a characteristic of the probe and is independent of the specimen material. Thereafter, measurements on various rectangular flaws with probes of different characteristic area were taken, and very good agreement between predicted and real depths was achieved. Both theory and experiments show that probe characterization is of particular importance when this method is used to measure surface crack depths in metals of low permeability such as aluminum.
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    Change in impedance of a single-turn coil due to a flaw in a conducting half space (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 37-43 
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    ISSN: 1573-4862
    Keywords: eddy current ; impedance ; lift-off ; flaw ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The problem of detection and characterization of a flaw in a conducting half-space using an eddy-current coil oriented parallel to the interface is examined. An expression is derived for a first order approximation for the change in complex impedance due to a flaw located within the conducting medium. The overall impedance is a function of the radius and lift-off distance of the test coil and the conductivity of the material. An analytical expression is derived for the change in impedance as a function of the electric fields at the position of the flaw. It is found to be an integral over the volume of the flaw of the electric fields found with and without the flaw being present. The limiting case of a degenerate point flaw may be examined in greater detail by allowing the field in the presence of the flaw to be approximated by the unperturbed field. For flaws small enough that the field does not vary much over its volume, the field may be even further approximated by using just the value of the field at the position of the centroid of the flaw. Plots are shown to illustrate the behavior of the change in impedance as a function of the radial range of the flaw and the depth of the flaw centroid, using previously derived expressions for the fields for the unflawed case.
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    Electromagnetic acoustic transducer for in-plane and plane-normal velocity measurements (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 85-91 
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    ISSN: 1573-4862
    Keywords: displacement-field ; acoustic radiation ; wave propagation ; absolute velocity ; EMAT ; mode selective ; nonresonant frequency response ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A new electromagnetic acoustic transducer (EMAT) is developed that measures velocities and absolute surface displacements in-plane and plane-normal to the direction of wave propagation. This transducer is flexible in shape and design to conform with irregular surfaces and has unique characteristics of nonresonant frequency response. Tests show that the sensitivity of this EMAT can be increased by increasing the applied magnetic field. Because this transducer is mode selective and nonresonent, its response can be related uniquely to the wave motion. This property is highly desirable for research purposes, though generally not wanted in field monitoring situations.
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    Two-dimensional radiographic imaging analysis (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 221-227 
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    ISSN: 1573-4862
    Keywords: Radiography ; point-spread function ; corner location ; edge location ; unsharpness ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Two-dimensional imaging properties of locally isotropic and isoplanatic point spread functions are described in a general radiographic context. In particular, the radiographic response to a two-dimensional wedge-shaped object is shown to possess several properties which enable the identification of the wedge corner on the image, thereby alleviating the need for image enhancement techniques. Extensions to the location of flat-edged boundaries are also discussed. The potential dimensioning application of this analysis lies in the precise and objective location of points of interest on radiographs of more complex two-dimensional objects.
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    Loss of specular reflection due to nonlinear crack-face interaction (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 229-239 
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    ISSN: 1573-4862
    Keywords: Crack-opening displacement ; crack closure ; ultrasonics ; Kirchoff approximation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The interaction between rough crack faces is modeled by nonlinear relations between the crack-face tractions and the crack-opening displacements. These relations account for crack closure and for the related resistance to crack-face sliding. The relations are used to investigate reflection and transmission of an incident pulse by an infinite flaw plane. The problem statement is reduced to a set of inhomogeneous nonlinear ordinary differential equations for the displacement discontinuities, [u] and [v], across the flaw plane. These equations have been solved numerically. The reflection and transmission of an incident pulse by a crack with interacting crack faces. Both incident longitudinal and transverse waves have been considered. The loss of specular reflection as compared to a perfect (traction-free) crack is exhibited by specific examples.
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    Acoustoelastic response of polycrystalline aggregates exhibiting transverse isotropy (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 1-8 
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    ISSN: 1573-4862
    Keywords: acoustoelasticity ; transverse isotropy ; polycrystalline aggregate ; cubic crystal ; third-order elastic constants ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Acoustoelasticity is an ultrasonic technique which has been used for the determination of active and residual stresses in common structural materials. This paper examines the effect of texture on the acoustoelastic response in polycrystalline bodies. In particular materials which are transversely isotropic aggregates of cubic crystals are studied. The second- and third-order elastic constants of the polycrystal are derived from the elastic properties of the constituent crystals, and the crystalline orientation relative to the body's symmetry axis. The acoustoelastic relations between velocity and deformation are then presented for the aggregate. Finally, evaluation of the acoustoelastic response for several ideal textures using data for aluminum single crystals shows that the response is highly dependent on the texture.
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    Photothermal examination of an adhesive layer (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 111-113 
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    ISSN: 1573-4862
    Keywords: photoacoustic microscopy ; delamination ; layered structure ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An adhesive layer, by which a piezoceramic foil is attached to an aluminum membrane for telephone application, is examined in a nondestructive way by thermal waves. The basic principles of the method are outlined, and its detecting power is demonstrated by evaluation of a well-defined delamination.
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    Finite element modeling of absolute eddy current probe signals (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 147-154 
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    ISSN: 1573-4862
    Keywords: finite element modeling ; eddy current ; absolute probe ; steam generator tubing ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Finite element analysis techniques are applied to the problem of predicting signals from an absolute eddy current probe in the tube sheet region of a PWR steam generator for the purpose of optimizing the probe coil geometry and determining the feasibility of using such a probe to characterize the condition of the tube and tube sheet crevice.
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    Relationships between crack opening displacement, alloy variables, and crack detection sensitivity (1982)
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    Journal of nondestructive evaluation 3 (1982), S. 189-200 
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    ISSN: 1573-4862
    Keywords: Acoustic harmonic generation ; critical angle acoustics ; fatigue crack detection ; alloy microstructure ; load amplitude ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Alloy grain size is known to influence both the propagation path and the closure stress of surface fatigue cracks in many alloys. The general trend is for the path to be more tortuous and the closure stress to be larger, the larger the grain size. By use of Ti Al-4V and Al 7075-T6, the effects of grain size on the nondestructive detection of surface cracks which might arise from closure stress and path irregularity variables were evaluated. Titanium specimens were inspected using an acoustic harmonic generation technique, and it was discovered that the major source of harmonic signals was grain sized crystallographic cracks. Harmonic signals were larger during fatigue in an 8-µm compared to a 4-µm grain sized alloy, as there were more grain sized cracks in the large grain material. Crack closure was found to be extremely important in determining the reflected acoustic amplitude obtained in inspecting small (100–1000 µm) cracks in Al 7075-T6 using a critical angle technique. Average received amplitudes were an order of magnitude smaller for cracks at zero load than for those opened by a tensile stress. The scatter in the reflected amplitude was also large, apparently as the result of variations in the degree of the closure from crack to crack. For the 7075 material, the important effect of larger grain size was to increase the irregularity of the crack path, making the small cracks more visible acoustically at azimuthal angles not normal to the crack plane.
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    Nondestructive evaluation of jades by means of 14 MeV neutron activation (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 137-145 
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    ISSN: 1573-4862
    Keywords: jadeite authentication ; 14 MeV neutrons ; jades ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Fourteen MeV neutron activation of jades was used to test the authenticity of jades: to ascertain whether they are genuine jadeite and whether their greenish colour is genuine, both of which are important criteria for the high market value of jadeite. For given activation and measurement conditions of the jades, the gamma-ray spectrum was observed to change as a function of the type of the jades; the counting ratio of the photopeaks from the two most prominent constituent elements varies greatly as a function of the type of the jades. The ratio of counts for the Compton edges of the 1.779 MeV gamma-ray of28Al, from28Si(n,p)28Al reaction, and the 1.434 MeV gamma-ray of52V, from52Cr(n,p)52V reaction, varied as a function of the type of the jades and also as a function of the color. These results can be applied for a fast and nondestructive evaluation of jades.
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    Frequency domain methods for reducing transducer variability (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 101-109 
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    ISSN: 1573-4862
    Keywords: ultrasonic transducers ; NDE ; deconvolution ; signal processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A major objective of quantitative nondestructive evaluation is to formulate defect detection, classification, and sizing algorithms that are insensitive to variations in transducer characteristics, material type, and defect depth. With the data used in this research, ultrasonic signals were found to vary significantly with changes in the transducer and only secondarily with changes in material and depth. It is shown that the method for minimizing signal variations due to transducer and material changes is to deconvolve the test signal with respect to the transducer response from a reference defect in a block of the same material. Since depth variation primarily affects signal amplitude and has minor impact on shape, detection, classification, and sizing, insensitivity to depth is achieved by avoiding the use of amplitude-dependent parameters. The notion of a “standard transducer” is introduced. Its mathematical properties and methods of realization are given. It is shown how the effects of variability from different test transducers can be removed by signal processing. When these procedures are applied to the test transducer, the effect is to cause it to resemble the standard transducer and, thereby, to place all ultrasonic waveforms on a common basis.
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    Ultrasonic attenuation and velocity in AS/3501-6 graphite fiber composite (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 137-148 
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    ISSN: 1573-4862
    Keywords: composite material ; ultrasonic velocity ; ultrasonic attenuation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The ultrasonic group velocity and attenuation were measured as a function of frequency for longitudinal and shear waves in the Hercules epoxy matrix (3501-6) and in the principal directions of the unidirectional Hercules graphite fiber epoxy composite (AS/3501-6). Tests were conducted in the frequency ranges 0.25–14 MHz and 0.5–3 MHz for longitudinal and shear wave modes, respectively. While the attenuation increased with frequency for all wave modes, the group velocity was independent of frequency for all wave modes. In studying the effects of transducer-specimen interface couplant and pressure, it was found that for each transducer, there exists a frequency-dependent “saturation pressure” corresponding to the maximum output amplitude of the signal.
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    URL: http://dx.doi.org/10.1007/BF00566121
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    On the acoustic emission due to the fracture of brittle inclusions (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 149-155 
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    ISSN: 1573-4862
    Keywords: acoustic emission ; fracture ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The far-field characteristics of the emission from a theoretical model for the fracture of brittle inclusions are presented in detail. The model is a circular crack growing at constant speed from zero size until it attains a prescribed size. The far-field radiation pattern is the same as that of a simple combination of force doublets, and some qualitative similarities between force doublets and acoustic dipoles are noted. The initial shape of the far-field pulses due to the growing stage and the stopping is determined, but difficulties arise in accounting for the diffraction of a surface wave on the crack faces generated by the stopping of the crack.
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    URL: http://dx.doi.org/10.1007/BF00567088
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    Elastic wave emission from damage processes (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 215-224 
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    ISSN: 1573-4862
    Keywords: Acoustic emission ; slip ; microcracking ; deformations ; displacement field ; elastic waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The theory of elastic wave emission (i.e., acoustic emission; AE) from damage processes such as slip and microcracking is discussed. Analogous developments in the literature on earth-quake seismology and dynamic dislocation theory are noted and utilized. A general representation of the displacement field of an AE event is given in terms of the double-couple response to a distribution of “moment density tensor” in the source region. Results are specialized to a point source model and to a general far-field analysis of outgoing elastic waves, and conditions for validity of such representations and their low-frequency specializations are noted. Emitted wave fields are compared for tensile opening and slip events, and procedures which might enable the approximate determination of the size or area increase of tensile microcracks are discussed.
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    URL: http://dx.doi.org/10.1007/BF00571803
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    Half-space radiation by EMATs (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 157-181 
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    ISSN: 1573-4862
    Keywords: EMAT ; radiation pattern ; transducer ; shear waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A Green's function calculation of the far-field radiation patterns of EMATs is presented. The approach is based on (a) closed form expressions for the eddy current and static magnetic field distributions, established by the EMATs, which react to produce the driving Lorentz forces, and (b) a Green's function derived from the steepest descent approximation to the far-field response of an arbitrary surface point force on a half space. Numerical results are presented, illustrating the radiation patterns of the three common EMAT designs. Included are vertically polarized shear waves as radiated by both meander coil and periodic magnet EMATs and horizontally polarized shear waves as radiated by the latter.
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    URL: http://dx.doi.org/10.1007/BF00567089
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    Fatigue lifetime prediction with the aid of SAW NDE (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 123-136 
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    ISSN: 1573-4862
    Keywords: fatigue life ; acoustic surface waves ; NDE ; ultrasonics ; cracks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The present studies concentrated on predicting the remaining fatigue life for single fatigue cracks in the Paris regime of macrocrack propagation. Acoustic surface waves were used to interrogate the crack during cyclic fatigue. The inversion of the obtained scattering data provided crack depth and crack length as a function of the number of cycles applied in tension-tension fatigue. Auxiliary experiments were conducted to study the acoustic response of the crack to tensile and compressive loads, thought to open and close the crack. The technique may allow for new insights into the physics of the “crack closure” effect.
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    URL: http://dx.doi.org/10.1007/BF00566120
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    Fracture mechanics transfer function for two-dimensional noncircular flaws (1980)
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    Journal of nondestructive evaluation 1 (1980), S. 201-206 
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    ISSN: 1573-4862
    Keywords: fracture mechanics ; noncircular crack ; fatigue life ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A transfer function that converts an irregularly shaped two-dimensional crack into an equivalent circular crack of equal propagation lifetime is proposed. The methodology extends the exact elliptical to circular crack transfer function to other noncircular cracks with geometries that slightly deviate from the elliptical. Results for rectangular, symmetric dumbbell, and asymmetric dumbbell cracks are presented.
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    URL: http://dx.doi.org/10.1007/BF00567092
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    Ultrasonic evaluation of geometrical and surface parameters of rough defects in solids (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 249-261 
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    ISSN: 1573-4862
    Keywords: Ultrasonics ; cracks ; surface roughness ; diffraction ; scattering ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Ultrasonic measurements from rough cracks were carried out using both broad-band and narrow-band methods. An analysis is suggested to determine parameters of the crack quantitatively such as size, shape, rms surface roughness, and distribution function of the surface roughness. Ultrasonic measurements of the parameters compare very well with the actual parameters of the defect.
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    URL: http://dx.doi.org/10.1007/BF00571806
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    Photoacoustic microscopy of ceramic engine hardware (1980)
    Springer
    Journal of nondestructive evaluation 1 (1980), S. 287-293 
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    ISSN: 1573-4862
    Keywords: Photoacoustic microscopy ; SPAM ; silicon nitride ; surface crack ; turbine vanes ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Scanning photoacoustic microscopy (SPAM) was applied to silicon nitride turbine hardware for purposes of detecting fabrication defects. SPAM traces in selected areas of complex-shaped turbine stator vanes were obtained and indicate that surface-crack detection of the order of tens of microns is possible. Means were devised to allow for multiple scans in areas previously inaccessible to other nondestructive techniques capable of detecting defects in the 25- to 100-µm range. The results show that SPAM is applicable to reaction-bonded silicon nitride turbine components and capable of detecting small surface-related defects.
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    URL: http://dx.doi.org/10.1007/BF00571809
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    Phagocytosis of spermatozoa by the ovum of the domestic fowl, Gallus gallus at the time of fertilization (1980)
    Springer
    Cell & tissue research 206 (1980), S. 55-63 
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    ISSN: 1432-0878
    Keywords: Phagocytosis ; Spermatozoa ; Ovum ; Fertilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatozoa with intact acrosomes, as well as those coming into contact with the ovum at a smaller angle, and morphologically abnormal spermatozoa reach the plasma membrane of the ovum via an extensively dissolved zone of the inner layer of the vitelline membrane. This zone is assumed to be formed by overlapping of two or more tunnels formed by spermatozoa that had previously come into contact with the ovum. When a spermatozoon comes into contact with the plasma membrane of the ovum, many cytoplasmic processes extend outwards and cover it. Thereafter, the plasma membranes of the processes fuse, thereby phagocytizing the spermatozoon. It is assumed that the phagocytized spermatozoa cannot undergo transformation into male pronuclei and that they degenerate soon after phagocytosis.
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    Ca++-induced structural changes in photoreceptor microvilli of diptera (1980)
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    Cell & tissue research 206 (1980), S. 225-232 
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    ISSN: 1432-0878
    Keywords: Compound eye ; Photoreceptor membrane ; Electron microscopy ; Calcium-induced changes ; Artefacts ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the compound eyes of the fly Lucilia are fixed for electron microscopy with glutaraldehyde in common buffer solutions, artefactual whorls are liable to be formed from the photoreceptor microvilli. The whorls result from two factors: (i) a prolonged time interval prior to osmication, such as the “overnight” primary fixation or wash at 4° C commonly used in studies of compound eyes; (ii) as little as 1–2 mM Ca++ in the primary fixative and wash solutions. Osmication after short (1 h) glutaraldehyde fixation at 4° C, or omission of Ca++ and addition of 2 mM EGTA, prevent whorl-formation. In the tipulid fly Ptilogyna, similar artefacts are produced, but are confined to the distal zone of the microvilli that sheds during turnover.
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    Scanning and transmission electron microscopic observations of the cloacal epithelia of the domestic fowl (1980)
    Springer
    Cell & tissue research 211 (1980), S. 83-93 
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    ISSN: 1432-0878
    Keywords: Epithelium ; Cloaca ; Electron microscopy ; Hen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithela of the three divisions (coprodaeum, urodaeum, proctodaeum) of the cloaca of the hen, and of the excretory ducts (colon, ureter, vagina) which join the divisions, are described using light microscopy, and scanning and transmission electron microscopy. Each region of the cloaca has its typical epithelium. Special attention is focussed in this study on the boundaries between the different epithelia. The coprodaeal epithelium does not differ considerably from that of the colon; a transitional zone is not visible. Distinct border zones, however, are observed between the other regions (ureter — urodaeum; vagina — urodaeum and proctodaeum; urodaeum-proctodaeum; proctodaeum — cutis). Although the vaginal opening is generally thought to lie in the urodaeum, our investigations show that at the vaginal opening into the cloaca the ciliated epithelium changes, on one border to a secretory epithelium characteristic of the urodaeum and on the other border to that characteristic of the proctodaeum. These observations are discussed in relation to functional aspects.
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    Ultrastructural alterations of the pancreatic D cell in the domestic fowl following vagotomy (1980)
    Springer
    Cell & tissue research 211 (1980), S. 171-174 
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    ISSN: 1432-0878
    Keywords: Pancreatic D cell ; Neural control ; Vagotomy ; Electron microscopy ; Fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to determine the neural control of pancreatic D cells, the pancreatic islets of the domestic fowl were examined electron microscopically from 1 to 28 days after abdominal vagotomy. Exocytotic release of many secretory granules from D cells occurred one day after vagotomy. Rough endoplasmic reticulum developed and formed an arrangement of concentric whorls in the cytoplasm of D cells after axotomy. The altered D cells were also characterized by the occurrence of many peculiar dense bodies in the apical cytoplasm at all time periods studied. These bodies varied in shape and size, containing several round vesicles. The D cells were extensively depleted of granules after the longer time periods following vagotomy. The present results provide new morphological evidence for the vagus-nerve control of D cells, which may regulate the activity of islet cells.
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    URL: http://dx.doi.org/10.1007/BF00233732
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    Fetal hypothalamic transplants in the third ventricle of the adult rat brain (1980)
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    Cell & tissue research 211 (1980), S. 191-206 
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    ISSN: 1432-0878
    Keywords: Hypothalamus ; Transplants ; Vasopressin ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Blocks of anterior hypothalamus were transplanted from 19 day-old fetuses of Wistar/Lewis rats into the third ventricle of adult male Brattleboro rats. Physiological changes in graft recipients and in sham-operated animals were monitored daily. Twenty days after surgery, the graft recipients and shamoperated animals were killed and their brains examined by correlative scanning and transmission electron microscopy. Host animals that exhibited both decreased polydipsia and increased urine concentration were found to have viable grafts within the third ventricle. The observed physiological changes suggested that synthesis and release of vasopressin occurred in the transplanted neurons. Grafts were well vascularized by vessels arising from the host hypothalamus. Neurons, with perikarya ranging from 8 to 30 μm in diameter, glial cells, and neurites were located throughout the transplants. A neurohemal contact zone, similar to that normally seen in the median eminence, could not be demonstrated in the grafts. The absence of complete glial and ependymal barriers indicates a relatively close association between cells in the transplants and the cerebrospinal fluid. A large increase in supraependymal neurons and their processes, including an eruption of neurons through the floor of the third ventricle in one animal, was observed in graft recipients but not in shamoperated animals.
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    Fine structure of ependymal cysts in and around the area postrema of the rat (1980)
    Springer
    Cell & tissue research 206 (1980), S. 303-318 
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    ISSN: 1432-0878
    Keywords: Area postrema, rat ; Ependyma ; Cyst ; Circumventricular organs ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peculiar cells forming cysts were observed in the area postrema and sometimes also in the choroid plexus and the tela chorioidea near the area postrema, and were studied in detail by electron microscopy. The cytological features of the cyst cell and its junctional relationship to neighboring cells imply that cyst cells are derived from ependymal and choroid epithelial cells. The cyst cells usually contact directly the perivascular spaces of postremal, choroidal or pial capillaries, where the cytoplasm is often considerably attenuated. The cystic lumen is commonly filled with a flocculent material. The limiting membrane of the cystic lumen, which frequently bears cilia and microvilli, has the same thickness as the surface cell membrane. In many cases, the cyst is surrounded by the cytoplasm of a single cell. In some cases, however, two cells participate in the formation of the cyst, although one is only a slender process and joined by a zonula occludens with the main cyst cell. Horseradish peroxidase (HRP) injected into the cerebrospinal fluid (CSF) space failed to enter the cystic lumen. A possible significance of the cyst in relation to the CSF and blood circulation was considered.
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    Incorporation of 3H-oleic acid by the proximal convoluted tubule cells of the chick (Gallus domesticus) (1980)
    Springer
    Cell & tissue research 210 (1980), S. 447-459 
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    ISSN: 1432-0878
    Keywords: Lipid ; Kidney tubules, proximal ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lipid metabolism in the cells of the renal proximal convoluted tubules (PCT) was investigated in healthy fowls and in fowls with the Fatty Liver and Kidney Syndrome (FLKS). The tissue was fixed at 10–25 min intervals after intravenous injection of 3H-oleic acid. The distribution of autoradiographic grains was analysed by the “circle method”. In normal cells most of the silver grains were associated with the cytoplasmic organelles. Lipid droplets and Golgi elements had the highest specific activity relative to the nuclear activity, which was little above background level. Lysosome-like bodies and mitochondria had lower values. In the cells of the FLKS-affected birds a large proportion of the grains was located over the lipid droplets, which are abundant in this condition. The specific activity of the cytoplasmic organelles was barely 2-fold higher than the nuclear activity. The results suggest that there is a diminished incorporation of esterified fatty acids by the organelles of these cells and that the excess is transferred to the lipid droplets. The identity of low electron density particles observed in the PCT cells of severely affected birds is discussed.
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    Gut hormones in Salamandra salamandra (1980)
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    Cell & tissue research 211 (1980), S. 331-343 
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    ISSN: 1432-0878
    Keywords: Gut hormones ; Endocrine cells ; Electron microscopy ; Immunocytochemistry ; Peptidergic innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, cytochemical and immunocytochemical methods were used in light and electron microscopical studies to demonstrate the presence of a neuroendocrine system in the gut of the urodele, Salamandra salamandra. Cytochemical stains capable of detecting peptide-producing endocrine cells demonstrate cells reacting with Masson's silver (argentaffin) method, Grimelius' argyrophil silver method, masked metachromasia method and the lead haematoxylin stain. Using antisera raised to a variety of mammalian gut peptides, cells containing bombesin-, gastrin-, somatostatin-, substance P- and glucagon-like immunoreactivity were identified; vasoactive intestinal polypeptide- and substance P-like immunoreactivities were found in nerve fibres in the submucous and myenteric plexus. No immunoreactivity was detected for motilin, gastric inhibitory polypeptide, cholecystokinin or secretin. The ultrastructure of the immunoreactive cells and nerves was revealed by the semithin/thin method. All the cells identified contained numerous electrondense secretory granules, which varied in their chracteristic morphological structure from one cell type to another. The evidence collected in this study indicates that a complex neuroendocrine system regulating gut function is present in this amphibian and may have developed prior to the emergence of the phylum.
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    Monoaminergic neurons of the mudpuppy retina (1980)
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    Cell & tissue research 210 (1980), S. 269-282 
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    ISSN: 1432-0878
    Keywords: Monoaminergic neurons ; Retina ; Amacrine cells ; Neurotoxins ; Mudpuppy, Necturus maculosus ; Neurotransmitters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mudpuppy retina was investigated with the histofluorescence method of Falck and Hillarp in normal animals and in animals injected intraocularly with α-methylnoradrenaline, 5,6-dihydroxytryptamine, or a combination of the two drugs. Catecholaminergic amacrine cells were found to form a thin layer of terminals at the border between the inner nuclear and the inner plexiform layers. Catecholaminergic interplexiform cells were not found. Indoleamine-accumulating amacrine cells were also observed. They are fifteen to twenty times more numerous than the catecholaminergic cells, and their terminals occur diffusely throughout the inner plexiform layer. In a number of eyes the majority of the indoleamine-accumulating terminals were eliminated with intraocular injections of the neurotoxin, 5,7-dihydroxytryptamine, but the reproducibility of this effect was not consistent. Intravitreal injections of 5,6-dihydroxytryptamine were used to label both types of neurons for electron microscopy. They were found to make conventional type synapses on amacrine cells and, less frequently, on bipolar cells.
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    Merkel cells and nerve endings in the labial epidermis of a lizard (1980)
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    Cell & tissue research 210 (1980), S. 353-357 
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    ISSN: 1432-0878
    Keywords: Merkel cells (reptiles) ; Epidermis ; Lizard ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of the labial epidermis of the lizard Lacerta sicula revealed cells displaying all features of Merkel cells. These cells are located in the stratum basale of epidermal pegs and are arranged in clusters.
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    Ultrastructural changes in Paneth cells during hibernation in the ground squirrel Spermophilm lateralis (1980)
    Springer
    Cell & tissue research 211 (1980), S. 293-301 
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    ISSN: 1432-0878
    Keywords: Paneth cell ; Hibernation ; Intestine ; Hypothermia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Paneth cells from jejuno-ileal segments of the small intestine of the ground squirrel, S. lateralis, was examined under normal euthermic conditions and during the profoundly depressed metabolic conditions of natural hibernation. Paneth cells obtained from hibernating animals gave evidence of markedly reduced activity when compared to Paneth cells from euthermic animals. In hibernating animals, the nuclei were smaller, with less prominent nucleoli and with an increased proportion of heterochromatin. In hibernating animals, the rough endoplasmic reticulum was fragmentary and poorly organized, in contrast to the typical arrangement of concentric lamellae seen in euthermic animals. Although the total number of ribosomes was decreased in hibernating animals, there were proportionally more free ribosomes than in euthermic animals. Paneth cells from hibernating animals also contained a greater number of apical secretory granules which were smaller and more variable in electron density than granules from control animals. These ultrastructural features indicate that during hibernation the Paneth cell is relatively quiescent.
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    Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure (1980)
    Springer
    Cell & tissue research 207 (1980), S. 511-517 
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    ISSN: 1432-0878
    Keywords: Female hamster ; Harderian gland ; Testosterone ; Tubular clusters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.
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    Microtubules, dendritic spines and spine apparatuses (1980)
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    Cell & tissue research 208 (1980), S. 171-181 
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    ISSN: 1432-0878
    Keywords: Microtubules ; Dendritic spine apparatus ; Synapse ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using techniques for enhanced microtubular preservation, including albumin pretreatment (Gray, 1975), occipital cortex of rats was studied electron microscopically at various ages of development. A close structural relationship was seen between microtubules, sacs of SER and the postsynaptic “thickening” in primordial spines and with the dense “plate” material of spine apparatuses. Stereoscopic preparations in addition show a more complicated substructure than previously described for the “plate”. Microtubules may contribute to the formation of the “plate” of the spine apparatus which in turn is associated with the postsynaptic “thickening” of the mature spine. Possible functional correlates are discussed.
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    Survival of satellite cells following exposure to the local anesthetic bupivacaine (Marcaine) (1980)
    Springer
    Cell & tissue research 209 (1980), S. 131-135 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Bupivacaine ; Degeneration ; Satellite cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat lumbrical muscles were incubated in a concentration of 10-2 M bupivacaine for 5 or 15 min and examined after further incubation in the absence of the drug for periods totalling 1, 2, and 3h. Electron microscopy showed that muscle fibers and their component organelles and myonuclei underwent a series of irreversible degenerative changes. However, satellite cells retained their normal morphology under similar conditions. It is concluded that satellite cells are responsible for the rapid regeneration of muscles that follows degeneration induced by bupivacaine. The role of satellite cells in muscle regeneration is discussed.
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    Ultrastructural changes in the urophysis of Mollienesia sphenops following adaptation to seawater (1980)
    Springer
    Cell & tissue research 207 (1980), S. 135-142 
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    ISSN: 1432-0878
    Keywords: Caudal neurosecretory system ; Poeciliidae ; Electron microscopy ; Salinity changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The urophysis or neurohemal contact site of the caudal neurosecretory system of Mollienesia sphenops, the black molly, was studied in animals adapted to an artificial seawater environment. This species of fish was chosen for these studies because of its known ability to osmoregulate and its adaptability to the laboratory aquarium. The urophysis of freshwater acclimated mollys contained an abundance of neurosecretory granules. However, in fish subjected to a seawater environment for one week the number of neurosecretory granules was significantly decreased. In addition, there was an increase in blood cell infiltration of the urophysis.
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    URL: http://dx.doi.org/10.1007/BF00239335
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    Studies on the juxtaglomerular apparatus VI. Sympathetic innervation, catecholamines and the renin-angiotensin-system in rats and tree-shrews (Tupaia belangeri) (1980)
    Springer
    Cell & tissue research 212 (1980), S. 375-382 
    Details
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Sympathetic innervation ; Renin-angiotensin system ; Electron microscopy ; Fluorescence microscopy ; Tupaia belangeri ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has previously been reported that the primitive primate Tupaia belangeri develops a renal failure when exposed to psychosocial stress. In order to learn if this high susceptibility to stress of the Tupaia kidney can be correlated with morphological and functional parameters of the Juxtaglomerular apparatus (JGA) and the renin-angiotensin system, comparative experiments were performed on Tupaia and rat. Our results reveal an outstandingly high potency of the JGA and the renin-angiotensin system in Tupaia as evident from the following findings: The Tupaia JGA contains a great number of epithelioid cells abounding in renin granules (electron microscopy). The renin content of the Tupaia kidney is considerably higher than in the rat (radio-immunoassay). The sympathetic innervation of the kidney and especially of the JGA is abundant in Tupaia (fluorescence and electron microscopy). Catecholamine contents of the kidney and other organs are significantly higher in Tupaia than in rats (spectrophotofluorometry). Our results support the previously developed concept of a potent intrarenal neuroendocrine interaction at the JGA level favouring, under certain conditions of social stress, the development of acute renal failure in Tupaia belangeri.
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    URL: http://dx.doi.org/10.1007/BF00236504
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    Electron microscopic study of the paracortical postcapillary “high endothelial venules” in lymph nodes of the normal calf (1980)
    Springer
    Cell & tissue research 212 (1980), S. 465-474 
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    ISSN: 1432-0878
    Keywords: Postcapillary venules ; Calf ; Lymph nodes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the postcapillary “high endothelial venules” (HEV) of lymph nodes in calves was studied light and electron microscopically. These venules were detected light microscopically in the paracortical zone by their high cuboidal endothelium, a distinct basal lamina, the migration of lymphocytes through the vessel wall, and the dominance of lymphoid cells in the lumen, often completely obliterating the latter. Ultrastructurally, the endothelial cells (HEC) of the HEV were characterized by a prominent Golgi complex including many small vesicles, a few lysosome-like bodies, and a specific association between mitochondria and rough endoplasmic reticulum (MER). The HEC are connected by desmosomes, whereas the intimate contact points between migrating lymphocytes and endothelial cells could not be classified according to the well-defined junctional types. Lymphocyte migration occurred predominantly intercellularly, i.e., between endothelial cells. Although the overall appearance of the described vessel type in bovines bears resemblance to HEV in other investigated species, several differences occur that most probably are related to species variation.
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    URL: http://dx.doi.org/10.1007/BF00236511
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    Sensory organs inIps typographus (Insecta: Coleoptera) — Fine structure of antennal sensilla (1982)
    Springer
    Protoplasma 111 (1982), S. 206-214 
    Details
    ISSN: 1615-6102
    Keywords: Bark beetle ; Sensilla ; Chemoreceptors ; Mechanoreceptors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The antennal sensilla inI. typographus are almost exclusively confined to the flattened terminal flagellar segment. The sensillar types have distinct distribution patterns in the three areas where they are found. Judging from the ultrastructural characteristics the following functions can be assigned to the sensillar types: chemoreception, single-walled and double-walled sensilla; chemoreception/mechanoreception, terminal-pore sensillum. Moreover there are two types of mechanoreceptors, one of which is connected to a bristle, whereas the other terminates within the cuticle of the flagellar segment.
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    URL: http://dx.doi.org/10.1007/BF01281968
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    Some observations onHaemohormidium cotti Henry 1910, from the marine fishCottus bubalis euphrasen (1980)
    Springer
    Parasitology research 62 (1980), S. 31-38 
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    ISSN: 1432-1955
    Keywords: Haemohormidium cotti ; Light microscopy ; Electron microscopy ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Haemohormidium cotti, an organism of uncertain status, is redescribed from one of its type hosts, the marine fish,Cottus bubalis. The parasite occurs as irregularly round, oval, or elongate, intraerythrocytic bodies within blood and tissue preparations. Electron micrographs show features which suggest thatH. cotti may, as previously suspected, belong with the Piroplasmasida but no firm evidence of this is established. Possible division stages are identified in both light and electron micrographs. The taxonomic position ofHaemohormidium is discussed.
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    URL: http://dx.doi.org/10.1007/BF00925364
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    Babesia microti (Apicomplexa: Piroplasmida): Electron microscope detection in salivary glands of the tick vectorIxodes ricinus (Ixodoidea: Ixodidae) (1980)
    Springer
    Parasitology research 64 (1980), S. 113-115 
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    ISSN: 1432-1955
    Keywords: Babesia microti ; Electron microscopy ; Ticks ; Ixodes ricinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00927061
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    Cells and intercellular contacts in glomeruli and tubules of the frog kidney (1982)
    Springer
    Cell & tissue research 226 (1982), S. 589-608 
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    ISSN: 1432-0878
    Keywords: Kidney (frog) ; Glomerulus ; Nephron ; Tight junctions ; Freeze-fracturing ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of thin sections and freeze-fracture replicas the glomerular and tubular structures of the kidney of the frog (Rana esculenta) were studied with special reference to intercellular junctions. In the glomerulus the filtration barrier is of very variable thickness, and frequent tight and gap junctional contacts occur between podocyte processes. Although structurally less elaborate, the proximal tubule resembles its mammalian counterpart. In the initial part the tight junctions are relatively shallow but become very broad in the mid and distal portions of the proximal tubule. The proximal tubular cells are extensively linked by gap junctions. In some animals the shapes of the cells in the proximal and distal portions of the proximal tubule were markedly different. The distal tubule consists of two segments which differ mainly in the pattern of interdigitations and the structure of the zonulae occludentes. Similarities with the tight junctional morphology of the mammalian distal tubule are striking. In the first part of the distal tubule (diluting segment) a narrow band of parallel tight junctions is found closely resembling that found in the mammalian straight distal tubule; in the more distal part of the distal tubule, however, a broad band of anastomosing tight junctional strands exists, like the zonula occludens of the mammalian convoluted distal tubule. The connecting tubule displays cellular dimorphism: its wall contains a mixture of light and dark (flask) cells. The luminal and basolateral membranes of the flask cells are covered with numerous rod-shaped particles. The tight junctions of the connecting tubule are broad and increase in depth and number of strands along its length; they are typical of a very tight epithelium. In spite of several dissimilarities with phylogenetically younger kidneys our findings suggest that many structural principles of the mammalian kidney are also represented in the kidneys of amphibians. The structural-functional relationships are discussed.
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    Pancreatic polypeptide (PP)- and glucagon cells in the pancreatic islet of Xiphophorus helleri h. (Teleostei) (1980)
    Springer
    Cell & tissue research 205 (1980), S. 187-198 
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    ISSN: 1432-0878
    Keywords: Pancreatic polypeptide (PP) ; Glucagon ; Pancreatic islet ; Xiphophorus helleri ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'étude immunohistochimique de l'îlot pancréatique du poisson téléostéen Xiphophorus helleri, à l'aide de sérums anti-polypeptide pancréatique (PP) et anti-glucagon a permis de montrer que deux populations cellulaires distinctes sont responsables de la sécrétion de ces hormones. L'observation comparée de coupes sériées, ultrafines et semifines, traitées par la technique immunohistochimique, a démontré que les cellules à PP correspondent aux cellules qui avaient été précédemment définies, dans cette espèce, comme “cellules A2 à grains ronds” et que les cellules sécrétrices de glucagon sont les “cellules A2 à grains cristallins”. L'hypothèse de l'existence de deux catégories de cellules à glucagon chez les téléostéens est abandonnée.
    Notes: Summary Correlative immunohistochemical and electron microscopical studies on the pancreatic islet of the teleost fish Xiphophorus helleri using antibodies to pancreatic polypeptide (PP) and glucagon show that separate cell types are responsible for the production of these peptides. The PP-cells correspond to the previously described “A2-cells with round granules”, while the “A2-cells with crystalline granules” are the true glucagon cells. An earlier suggestion that there are two types of glucagon cells in teleost islets is therefore withdrawn.
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    URL: http://dx.doi.org/10.1007/BF00234679
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    The number and arrangement of elements in the lamina cartridge of the dragonfly Sympetrum rubicundulum (1980)
    Springer
    Cell & tissue research 206 (1980), S. 395-401 
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    ISSN: 1432-0878
    Keywords: Dragonfly visual system ; Lamina ganglionaris ; Monopolar cells ; Optic neuropile ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Five monopolar cells and two long visual fibres are a consistent component of the lamina cartridge of the ventral half of the eye of the dragonfly Sympetrum rubicundulum. They communicate with the chiasm via a cartridge axon bundle comprising a minimum of ten fibres. The arrangement of these elements is documented with respect to the ommatidial photoreceptor axon bundle innervating them. These relationships are described both within the lamina cortex and in the cross-section of the underlying cartridge.
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    URL: http://dx.doi.org/10.1007/BF00237969
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    Lactate sensitive cells in newt kidneys (1980)
    Springer
    Cell & tissue research 207 (1980), S. 233-239 
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    ISSN: 1432-0878
    Keywords: Kidney ; Triturus cristatus carnifex ; Erythropoiesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Specimens of Triturus cristatus carnifex (Laurenti), raised in 3.2 g/l solution of sodium lactate, presented hypertrophy of “lactate sensitive cells” (LSC) clustered at the vascular pole of each renal corpuscle. As seen under both the light and electron microscopes, these are specialized cells of the Bowman's capsule located at the junction between its visceral and parietal layers. The structure formed by the cells, heretofore unknown, is topographically associated with the juxtaglomerular apparatus. As lactate stimulates erythropoiesis even in normal oxygenated specimens and hypoxia induces hypertrophy of LSC in newts, it is hypothesized that the LSC are the site of erythropoietin (ESF) synthesis. A scheme of ESF biogenesis in newts, integrating the above principles, concludes the paper.
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    Ontogeny and organization of the stationary non-lymphoid cells in the human thymus (1980)
    Springer
    Cell & tissue research 207 (1980), S. 287-306 
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    ISSN: 1432-0878
    Keywords: Fetal human thymus ; Epithelial cells ; Development and differentiation ; Mesenchymal reticulum cells ; T lymphocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ontogenetic differentiation of the human thymus was investigated in 50 embryos by means of light and electron microscopic methods in an attempt to clarify the morphogenesis of the complicated microecology of thymic tissue. At the 8th gestational week (g.w.), the primordium of the thymus contains almost exclusively undifferentiated epithelial cells. At the 10th g.w., the epithelial cells in the central part are spindle-shaped. During the subsequent weeks the cortical region of the thymus becomes separated into lobes by mesenchymal septa containing hemopoietic precursor cells and large electronlucent cells with irregularly shaped nuclei. The latter cells are also found in the deeper presumptive medullary regions of the thymus; they differentiate into interdigitating reticulum cells (IDC). The permeation of the medulla of the thymus by non-epithelial IDC occurs concurrently with the formation of cortical and medullary epithelial cells. Between the 12th and 14th g.w. the cortical and medullary differentiation is completed. At this time-stage cortical small lymphocytes differ in morphological shape from medullary lymphocytes, the latter acquiring the appearance of immunocompetent T cells and establishing intimate contact with the IDC. These findings indicate that the thymic cortex and medulla contain different epithelial cells. In addition, the thymic medulla displays cells characterized by the morphology of typical interdigitating reticulum cells of peripheral lymphoid tissue. The structural pattern of the thymus is correlated to morphologically differing lymphoid cell populations in the cortical and medullary regions.
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    URL: http://dx.doi.org/10.1007/BF00237813
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    Scanning and transmission electron microscopic study of the supraependymal macrophages in the lateral ventricles of the toad brain (1980)
    Springer
    Cell & tissue research 207 (1980), S. 321-329 
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    ISSN: 1432-0878
    Keywords: Supraependymal cells ; Macrophages ; Electron microscopy ; Lateral ventricles ; Amphibian brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission and scanning electron microscopy of the lateral ventricles of the toad brain revealed the presence of supraependymal cells that have the features of macrophages. Based solely on their surface morphology three different cell forms could be identified. The most frequently observed cells are flat and multipolar, and have a smooth or ruffled surface. The second type is spherical with a ruffled surface and occurs either singly, in which case it lacks processes, or in clusters from which processes radiate. The third type has surface blebs and numerous thin, smooth processes. However, when specimens that had been examined in the scanning electron microscope are viewed in the transmission electron microscope, all cells appear to belong to a single cell type. All cells viewed closely resemble macrophages in that they contain nuclei with clumped chromaffin, single cisternae of rough endoplasmic reticulum, numerous dense bodies, and many Golgi complexes. In addition, when horseradish peroxidase (HRP) was perfused into the ventricles, reaction product was found a short time thereafter within cytoplasmic vacuoles, and after a longer period within dense bodies. Because of their ultrastructural resemblance to macrophages and their capacity to ingest HRP, we suggest that these cells function as phagocytes and, as such, act to remove foreign materials from the cerebrospinal fluid.
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    Organ culture of the islets of Langerhans from young and senescent rats (1980)
    Springer
    Cell & tissue research 207 (1980), S. 429-448 
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    ISSN: 1432-0878
    Keywords: Islet of Langerhans ; Aging ; Insulin-secreting cells ; Organ culture ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The B-cells of the endocrine pancreas constitute an adequate model for in vitro study of the aging process in highly differentiated cells. In the present study, collagenase-isolated islets of Langerhans from young and senescent rats were cultured up to 28 days. The response of the B-cells to the stimulatory conditions of the culture medium involved the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, and secretory granules. Correlated data from light microscopy, electron microscopy, and insulin radioimmunoassay show that the differentiation and function of senescent B-cells are maintained in culture, as it has been proven for the B-cells of younger animals. On the other hand, signs of cytological deficiency not directly concerned with the specific function of B-cells were observed: abnormal mitochondria and lysosomes are more numerous in the senescent B-cells. The proliferative capacity of the B-cells of aged rats is reduced.
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    URL: http://dx.doi.org/10.1007/BF00224618
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    An electron microscopic study of the salivary gland of Rhynchosciara angelae (1980)
    Springer
    Cell & tissue research 207 (1980), S. 449-461 
    Details
    ISSN: 1432-0878
    Keywords: Rhynchosciara angelae ; Salivary gland ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the salivary gland of the dipteran insect Rhynchosciara angelae in a defined stage of the larval development, characterized by the synthesis and storage of secretion product, is described. Observations were made with both Nomarski optics and electron microscopy. Filiform projections extending into the lumen of the gland were observed in the apical portion of the cells. At the basal region junctions, characterized as hemidesmosomes, were observed between the membrane of the cell and the basal lamina. The plasma membrane presents numerous infoldings into the cell increasing considerably the surface area at this region. Throughout the cytoplasm of the gland cells numerous mitochondria, Golgi complexes, microtubules, profiles of endoplasmic reticulum, secretion granules and glycogen granules were observed. Carbohydrates were detected on ultrathin sections by using the periodic acid-silver methenamine and the periodic acid-thiosemicarbazide-silver proteinate techniques.
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    Fibre types in the locomotory muscles of an antarctic teleost, Notothenia rossii (1980)
    Springer
    Cell & tissue research 208 (1980), S. 143-164 
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    ISSN: 1432-0878
    Keywords: Locomotory muscle ; Fibre types ; Antarctic fish (Notothenia rossii) ; Histochemistry ; Electron microscopy ; Energy metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The metabolic and structural differentiation of locomotory muscles of Notothenia rossii has been investigated. In this species sustained locomotion is achieved by sculling with enlarged pectoral fins (labriform locomotion), whilst the segmental myotomal muscle is reserved for burst activity. Red, white and subepidermal fibres can be distinguished in the trunk by histochemical and ultrastructural criteria. The main pectoral muscle (m. adductor profundus) consists entirely of red fibres. These three main fibres types show differences in histochemical staining profiles, capillarization, myofibril shape and packing, and lipid and mitochondrial content. The fractional volume of mitochondria amounts to 38% for pectoral, 30% for red myotomal and 1.9% for white myotomal fibres. Enzyme activities of red pectoral muscle are consistent with a higher potential for aerobic glucose and fatty acid oxidation than for the red myotomal fibres. Mg2+ Ca2+ -myofibrillar ATPase activities are similar for red pectoral and myotomal muscles and approximately half of those white fibres. Specialisations of N. rossii muscles associated with labriform swimming and locomotion at Antarctic temperatures are discussed.
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    The fine structure of the stomach mucosa of the llama (Llama guanacoe) (1980)
    Springer
    Cell & tissue research 208 (1980), S. 207-228 
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    ISSN: 1432-0878
    Keywords: Hind stomach ; Fundic glands ; Electron microscopy ; Histochemistry ; Endocrine cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron density of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.
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    The synaptic organization of visual interneurons in the lobula complex of flies (1980)
    Springer
    Cell & tissue research 208 (1980), S. 371-387 
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    ISSN: 1432-0878
    Keywords: Lobula complex ; Visual interneurons ; Ultrastructure ; Cobalt-impregnations ; Electron microscopy ; Diptera (Calliphora erythrocephala)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The synaptic organization of three classes of cobalt-filled and silver-intensified visual interneurons in the lobula complex of the blowfly Calliphora (Col A cells, horizontal cells and vertical cells) was studied electron microscopically. The Col A cells are regularly spaced, columnar, small field neurons of the lobula, which constitute a plexus of arborizations at the posterior surface of the neuropil and the axons of which terminate in the ventrolateral protocerebrum. They show postsynaptic specializations in the distal layer of their lobula-arborizations and additional presynaptic sites in a more proximal layer; their axon terminals are presynaptic to large descending neurons projecting into the thoracic ganglion. The horizontal and vertical cells are giant tangential neurons, the arborizations of which cover the anterior and posterior surface of the lobula plate, respectively, and which terminate in the perioesophageal region of the protocerebrum. Both classes of these giant neurons were found to be postsynaptic in the lobula plate and pre- and postsynaptic at their axon terminals and axon collaterals. The significance of these findings with respect to the functional properties of the neurons investigated is discussed.
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    The pineal complex of the three-spined stickleback, Gasterosteus aculeatus L. (1980)
    Springer
    Cell & tissue research 209 (1980), S. 11-28 
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    ISSN: 1432-0878
    Keywords: Epiphysis cerebri ; Parapineal organ ; Fluorescence histochemistry ; Electron microscopy ; Gasterosteus aculeatus L ; Teleostei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal complex of the three-spined stickleback (Gasterosteus aculeatus L.) was investigated by light and electron microscopy, as well as fluorescence histochemistry for demonstration of catecholamines and indolamines. The pineal complex of the stickleback consists of a pineal organ and a small parapineal organ situated on the left side of the pineal stalk. The pineal organ, including the entire stalk, is comprised mainly of ependymal-type interstitial cells and photoreceptor cells with well-developed outer segments. Both unmyelinated and myelinated nerve fibres are present in the pineal organ. Nerve tracts from the stalk enter the habenular and posterior commissures. A small bundle of nerve fibres connects the parapineal organ and the left habenular body. The presence of indolamines (5-HTP, 5-HT) was demonstrated in cell bodies of both the pineal body and the pineal stalk, and catecholaminergic nerve fibres surround the pineal complex.
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    Lipid droplets in the visceral yolk sac endodermal cells of the postimplantation rat embryo: Application of malachite green-glutaraldehyde fixative (1980)
    Springer
    Cell & tissue research 209 (1980), S. 29-41 
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    ISSN: 1432-0878
    Keywords: Visceral yolk sac ; Lipid droplets ; Malachite green-glutaraldehyde fixative ; Rat embryo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the visceral yolk sac (VYS) of the rat embryo at day 9.5 of gestation was examined after fixation with either Karnovsky's glutaraldehyde-paraformaldehyde solution or malachite green-containing glutaraldehyde (MGA) solution. Fixation with MGA retained homogeneously electron-dense droplets in the cytoplasm and the nucleus of endodermal cells, both of which were lost in the specimens prepared by Karnovsky's fixation method. The cytoplasmic MGA-positive droplets were frequently associated with other cytoplasmic organelles such as rough endoplasmic reticulum, mitochondria and membrane-delineated inclusion bodies, but these cytoplasmic organelles never incorporated MGA-positive materials, whereas Golgi apparatus contained intracisternal MGA-positive droplets. Extracellular MGA-positive droplets were also encountered at the apical surface of endodermal cells and in the intercellular space between endodermal cells and the underlying mesodermal cells. These MGA-positive droplets were considered to be lipid in nature, and their origin in the endodermal cells of VYS is discussed.
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    Hypothalamo-hypophysial function following the lesion of tanycytes in the median eminence of the rat (1980)
    Springer
    Cell & tissue research 209 (1980), S. 225-238 
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    ISSN: 1432-0878
    Keywords: Tanycytes ; Median eminence ; Electron microscopy ; Rat ; Serum LH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transport of hormones from the cerebrospinal fluid to the adenohypophysis by the tanycytes of the median eminence was examined in male rats. Electron microscopy revealed that all ependymal cells including the tanycytes disappear or degenerate in rats subjected to electric cauterization of the ependymal layer lining the third ventricle. However, the granular axons in the palisade layer of the median eminence remain intact. In rats subjected to electric lesion, no significant change was found in either the serum-LH level or in the weight of the adenohypophysis, testes, adrenal and thyroid glands. It is concluded that the tanycytes do not participate in the hypothalamic regulation of hypophysial function.
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    URL: http://dx.doi.org/10.1007/BF00237628
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  • 87
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    Induction of intranuclear microtubules in chick embryo fibroblasts by frog virus 3 (1980)
    Springer
    Cell & tissue research 209 (1980), S. 271-277 
    Details
    ISSN: 1432-0878
    Keywords: Intranuclear microtubules ; Chick embryo fibroblasts ; Frog Virus 3 ; Electron microscopy ; Tubulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intranuclear microtubules appear in chick embryo fibroblasts upon infection with Frog Virus 3 (FV 3). Both the diameter and the annular shape of the microtubule profiles, established from electron microscopic observations using a goniometer, suggest that they are identical to naturally occurring cytoplasmic microtubules. Furthermore, the use of vinblastine allowed demonstration of the tubulin composition of the intranuclear microtubules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237631
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  • 88
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    The origin of the dendritic reticulum cell (1980)
    Springer
    Cell & tissue research 209 (1980), S. 279-294 
    Details
    ISSN: 1432-0878
    Keywords: Germinal center reaction ; Dendritic reticulum cell ; Rabbit spleen ; Enzyme histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To obtain more information concerning the origin of dendritic reticulum cells, the development of germinal centers in the spleens of rabbits was investigated by conventional light microscopy, enzyme histochemistry, and electron microscopy. Washed sheep erythrocytes were used as antigen. Splenic tissue was examined on the 13th, 18th, 21st, 27th and 48th day after antigen administration. Electron microscopic investigations revealed transitional forms between typical fibroblastic reticulum cells, which formed the framework of the entire splenic white pulp, and typical dendritic reticulum cells. During this transformation, the enzyme histochemical pattern of alkaline phosphatase disappeared and a positive alpha-naphthyl acetate esterase reaction appeared in the transformed cells. On the basis of these findings, it is highly likely that dendritic reticulum cells develop through transformation of fibroblastic reticulum cells during the development of germinal centers in rabbit spleens. The characteristic folding of the surface membrane of dendritic reticulum cells is probably caused by the conspicuous increase in size of the Golgi apparatus, the detachment of vesicles, and the uptake of such vesicles by the cell membrane observed electron microscopically during the cellular transformation. Receptors that are of significance in antigen trapping might reach the cell surface in this manner, i.e., with the Golgi vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237632
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  • 89
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    Dense material associated with apparent presynaptic elements in cell cultures of the CNS (1980)
    Springer
    Cell & tissue research 211 (1980), S. 95-103 
    Details
    ISSN: 1432-0878
    Keywords: Synapse ; Synaptogenesis ; Cell culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In cell cultures of the rat cerebellum, electron-dense material has been found occasionally between adjacent cells. More often than not, presynaptic elements on one side of the dense material faced either neuronal or nonneuronal cells on the other side. The 20 nm thick material was stained either with the osmium-uranyl-lead (OsUL) procedure or with the ethanolic phosphotungstic acid (E-PTA) procedure. To determine the source of the dense material, various compounds were added to cultures at 7 days in vitro. Only a crude nuclear fraction was able to duplicate the appearance of the dense material associated with the apparent presynaptic elements. It was concluded that apparent presynaptic elements were associated with the polybasic dense material and that this type of association may duplicate an interaction in the normal development of synaptic contacts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233726
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  • 90
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    The tight junctions of renal tubules in the cortex and outer medulla (1980)
    Springer
    Cell & tissue research 212 (1980), S. 395-413 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Distal tubule ; Collecting duct ; Electron microscopy ; Thin sections ; Freeze fracturing ; Tight junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative aspects of tight junction morphology were systematically studied in the cortical and outer medullary segments of the distal urinary tubules of rat, hamster, rabbit, cat, dog and the primitve primate Tupaia belangeri. Only minor differences in junctional architecture were found between straight and convoluted portions of the distal tubule. In contrast, the collecting duct in cortex and outer medulla, in all species, exhibits the most elaborate tight junctions observed along the uriniferous tubule. The present and previous findings from this laboratory indicate that increasing “tightness” of the junctional complexes is apparent along the course of the nephron in all species studied. The proposed relationship between quantitative aspects of the zonula occludens and presently available values for transepithelial electrical resistance was re-examined for the renal tubules. It was found that for the mammalian kidney a satisfactory correlation exists between the tight junction morphology and presently known functional parameters. This relationship is the more evident the more additional dimensional characteristics of the intercellular clefts are taken into consideration. It may therefore be concluded that, at least for the mammalian kidney, the assumption of differences in the molecular organization of the tight junctions is not needed to explain so far unresolved discrepancies between tubular morphology and function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236506
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  • 91
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    An electron microscopic study on stellate cells in the rabbit adenohypophysis under various endocrine conditions (1980)
    Springer
    Cell & tissue research 213 (1980), S. 237-246 
    Details
    ISSN: 1432-0878
    Keywords: Stellate cell ; Nongranulated cell ; Adenohypophysis ; Rabbit ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stellate cells in the rabbit adenohypophysis were observed electron microscopically under normal and experimental conditions such as lactation, thyroidectomy, adrenalectomy, or castration. In control animals stellate cells had a scanty cytoplasm surrounding the nucleus and possessed slender processes extending between granulated cells. The processes were interconnected by desmosomes to form a meshwork. In the cytoplasm, abundant microfilaments were present as well as ill-developed ordinary cell organelles, but secretory granules were absent. In the adenohypophysis of experimental groups, in which the granulated cells underwent characteristic changes, stellate cells also showed remarkable morphological alterations which were similar in all groups. In general, they became hypertrophied, and contained a well-developed Golgi apparatus and rough-surfaced endoplasmic reticulum. Lysosomes or lipid droplets were frequently encountered. Between adjacent stellate cells, intercellular canals were markedly developed and many microvilli were noticed. Based on the above data, it is suggested that the stellate cells are not only sustentacular elements, but play an important role in the function of the adenohypophysis, such as the supply of materials to granulated cells or the disposal of waste products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234784
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  • 92
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    The programming of silk-gland development in Bombyx mori (1980)
    Springer
    Cell & tissue research 213 (1980), S. 311-324 
    Details
    ISSN: 1432-0878
    Keywords: Bombyx ; Silk-gland ; Starvation ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cytological development of the silk gland has been studied by light and electron microscopy in silkworms experimentally starved at different periods of the natural feeding stage during the fifth instar. When newly molted animals are not provided with food, no sign of growth is observed. Starvation initiated early during the obligatory feeding period, stops cell growth and development of the organelles involved in protein synthesis and secretion, whereas it induces the appearance of organelles concerned with autolysis. These effects are reversible if starvation is not prolonged beyond two days. Starvation during the facultative feeding period, at the time of massive fibroin production, results in quantitative and qualitative modifications of organelles related to the decrease of fibroin production and the onset of autolysis. Rough endoplasmic reticulum, responsible for fibroin synthesis, forms transitory whorls. Fibroin transport via the Golgi apparatus and secretion of the protein into the gland lumen decrease parallel to fibroin synthesis, so that no fibroin storage can be detected in any organelle. After food deprivation, autophagosomes and secondary lysosomes rapidly develop in the cytoplasm, and if starvation continues portions of the cytoplasm are sequestered and completely destroyed. If animals are refed, fibroin production is resumed and autolysis declines. These ultrastructural alterations of the silk gland during experimental starvation are very similar to those observed during the periods of physiological starvation (molt and cocoon spinning) and generally considered to be under hormonal control. Our results raise the question of the nature of interactions between alimentary and hormonal factors which control silk-gland development.
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    URL: http://dx.doi.org/10.1007/BF00234790
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    Ultrastructure of endocrine cells in the stomach of two teleost fish Perca fluviatilis L. and Ameiurus nebulosus L. (1982)
    Springer
    Cell & tissue research 221 (1982), S. 657-678 
    Details
    ISSN: 1432-0878
    Keywords: Stomach (Teleost) ; Endocrine cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the gastric mucosa of two teleost species, the perch (Perca fluviatilis) and the catfish (Ameiurus nebulosus) three endocrine cell types were found, located predominantly between the mucoid cells of the gastric mucosa. A fourth cell type is present in the gastric glands of catfish. Each cell type was defined by its characteristic secretory granules. Type-I cells were predominant in both fish. These cells contained round or oval granules with a pleomorphic core. The average diameter of granules was 400 nm for the perch and 270 nm for the catfish. Type-II cells of both species displayed small, highly osmiophilic granules about 100 nm in diameter. The secretory granules of type-III cells (260 nm in the perch and 190 nm in the catfish) were round or slightly oval in shape and were filled with a finely particulate electron-dense material. Type-IV cells of the catfish were found in the gastric glands only. Their cytoplasm was filled with homogeneous, moderately electron-dense granules averaging 340 nm in diameter. The physiological significance of these different morphological types of gastric endocrine cells requires further investigation.
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    URL: http://dx.doi.org/10.1007/BF00215709
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    Apical region of the crayfish retinula (1982)
    Springer
    Cell & tissue research 222 (1982), S. 409-415 
    Details
    ISSN: 1432-0878
    Keywords: Crustacean compound eye ; Eighth retinular cell ; Crystalline tract ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The base of the crystalline tract, the distal part of the eighth retinular cell and its rhabdomer constitute a structural unit in the apical region of the retinula of Astacus fluviatilis and A. leptodactylus, shielded from the blood by a special covering cell.
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    URL: http://dx.doi.org/10.1007/BF00213221
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    Electron-microscopic localization of A2B5 cell surface antigen in monolayer cultures of murine cerebellum and retina (1982)
    Springer
    Cell & tissue research 224 (1982), S. 637-645 
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    ISSN: 1432-0878
    Keywords: Cell surface antigen ; Neurons ; Glia ; Electron microscopy ; Immunoperoxidase ; Monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immuno-electron microscopy was performed on live, cultured, early postnatal cerebellar and retinal cells of the mouse to identify A2B5 antigenbearing elements. In cerebellar cultures, granule cells, some immature oligodendroglia, and astroblasts express A2B5 antigen on their cell surfaces. The typical features of astroblasts include large cisternae of the endoplasmic reticulum and a mixed population of intermediate-sized filaments and microtubules. Immature oligodendroglia cells express the antigen on their cell bodies and on procecesses filled with cytoplasm. Cytoplasm-free membranous whorls, however, are devoid of A2B5 antigen, but not of 0 or NS-1 antigens. In retinal cultures, A2B5 antigen is observed on differentiating neurons with the exception of photoreceptor cells as identified by ribbon synapses.
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    URL: http://dx.doi.org/10.1007/BF00213758
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    Survival of Pacinian corpuscles after denervation in adult rats (1982)
    Springer
    Cell & tissue research 224 (1982), S. 673-683 
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    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, rat ; Denervation ; Sensory terminals ; Nerve degeneration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles located on the crural interosseous membrane was studied in adult rats 6 h to 10 months after transection of the right sciatic nerve. Axon terminals degenerated one day after transection and were engulfed and resorbed by cells of the inner core within one week. The axial space left after removal of the axonal debris was closed by the lamellae of the inner core. The main structural features of the inner core and capsule remained preserved after denervation throughout the period of study. The denervated inner cores, however, became atrophic 10 months after neurotomy, their mean diameter being reduced by 17.5% compared with that of contralateral control corpuscles. The number of capsular lamellae was unaltered, and perineurial pathways of the peripheral nerve stump remained preserved. Schwann cells proliferated and formed Büngner bands during the first month after denervation, but retracted their processes and became atrophic at later stages after neurotomy. Survival of Pacinian corpuscles after long-term denervation in adult rats is in contrast to their rapid degeneration within several days after nerve section in neonates.
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    URL: http://dx.doi.org/10.1007/BF00213762
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    Close apposition of muscle cells in the longitudinal bands of the body wall of a holothurian, Isostichopus badionotus (1982)
    Springer
    Cell & tissue research 227 (1982), S. 465-473 
    Details
    ISSN: 1432-0878
    Keywords: Electron microscopy ; Junctions ; Smooth muscle ; Echinodermata ; Holothuria, Aspidochirotida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy reveals that sarcolemmata of adjacent muscle cells form pentalaminar junctions by fusion of apposed trilaminar double leaflet membranes. These junctions appear to be candidates for low resistance pathways between muscle fibers. The muscles depolarize slowly when bathed in solutions containing elevated concentrations of KCl, and the sucrose gap method can then be used to measure the potential difference between polarized and depolarized regions. Thus the junctions which we have observed may provide the structural basis for electrical transmission through the sucrose gap.
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    URL: http://dx.doi.org/10.1007/BF00204778
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  • 98
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    Penetration of the peritrophic membrane of the tick by Babesia microti (1982)
    Springer
    Cell & tissue research 221 (1982), S. 471-481 
    Details
    ISSN: 1432-0878
    Keywords: Peritrophic membrane ; Tick ; Babesia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A peritrophic membrane (PM) has been demonstrated in the gut of feeding larvae, nymphs, and adults of the tick Ixodes dammini. This is the first report of a PM in ticks. This temporary structure divides the lumen of the gut into two compartments, an endoperitrophic space, the lumen proper, and an ectoperitrophic space located between the PM and the epithelial cells of the gut wall. The PM is a mechanical barrier and even such small particles as ribosomes derived from ingested reticulocytes are retained in the lumen proper; they are never found in the ectoperitrophic compartment. In Ixodes dammini fed on hamsters infected with Babesia microti some of the parasites are found in the ectoperitrophic space. This passage is accomplished by a highly specialized organelle, the arrowhead, which develops in some Babesia during their metamorphosis in the gut of the vector. The arrowhead, while passing through the PM, changes its fine structure and loses its internal organization as if releasing some of its contents. Its disintegration continues and it disappears shortly after the Babesia have entered the epithelial cells. Only Babesia equipped with the arrowhead structure are able to cross the PM. This is the first documented case of a parasite traversing a solidified PM.
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    URL: http://dx.doi.org/10.1007/BF00215696
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  • 99
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    Paddle cilia (discocilia) in chemosensitive structures of the gastropod mollusk Pleurobranchaea californica (1982)
    Springer
    Cell & tissue research 222 (1982), S. 25-40 
    Details
    ISSN: 1432-0878
    Keywords: Paddle cilia ; Discocilia ; Pleurobranchaea ; Chemoreceptors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy of various regions of the body of the marine gastropod Pleurobranchaea californica (McFarland) has revealed a characteristic cell type that bears cilia with dilated discoid-shaped tips. The tips of the cilia consist of an expansion of the ciliary membrane around a looped distal extension of the axoneme. These kinocilia have been observed in numerous other marine invertebrates and are generally referred to as paddle cilia (Tamarin et al. 1974) or discocilia (Heimler 1978). Although many functions have been proposed for paddle cilia, little empirical evidence supports any of the proposals. In Pleurobranchaea we have found that the distribution of this ciliated cell type corresponds exactly to areas of the body known from behavioral studies (Lee et al. 1974; Davis and Matera 1981) to mediate chemoreception. Transmission electron microscopy of the epithelium lining the rhinophores and tentacles of Pleurobranchaea revealed details of the ultrastructure of these ciliated cells and showed that they are primary receptors. These ciliated receptors lie in a yellow-brown pseudostratified columnar epithelium that superficially resembles the olfactory mucosa of vertebrates.
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    URL: http://dx.doi.org/10.1007/BF00218286
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    Pigment biogenesis in freshwater shrimp ventral nerve chord chromatophores (1982)
    Springer
    Cell & tissue research 222 (1982), S. 167-175 
    Details
    ISSN: 1432-0878
    Keywords: Pigment granules ; Chromatophores ; Granulogenesis ; Palaemonid shrimp ; Macrobrachium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The possible biogenesis of two pigment granule types present in the monochromatic, brown chromatosomes enveloping the ventral nerve chord of the freshwater palaemonid shrimps Macrobrachium acanthurus, M. heterochirus and M. olfersii is examined by transmission electron microscopy in thin section and freeze fracture replicas. Prominent, membrane limited granules are suggested to have their origin in a complex, juxtanuclear, smooth endoplasmic reticulum labyrinth, continuous with the nuclear envelope. Amembranous, lipocarotenoid granules possibly derive from the external surface of the smooth endoplasmic reticulum. Nuclear envelope and SER membranes contain numerous 11 nm diameter intramembranous particles while pigment granule membranes exhibit fewer particles. A dictyosomal origin for the lipocarotenoid granules is discounted. Granulogenesis is suggested to be a continuous process in crustacean chromatophores.
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    URL: http://dx.doi.org/10.1007/BF00218297
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