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  • Scanning electron microscopy  (111)
  • Stress
  • Springer  (121)
  • Wiley  (1)
  • 1975-1979  (84)
  • 1970-1974  (38)
  • 1
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    Springer
    Calcified tissue international 27 (1979), S. 33-40 
    ISSN: 1432-0827
    Keywords: Chick embryo ; Bone ; Organ culture ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The study describes the ultrastructure of the mineralized portion of chick tibiae from 10 days in ovo to 2 days post-hatch. At 10 days a single mineralized cylinder surrounds the diaphysis. On its outer surface columnar trabeculae join to form ridges parallel to the long axis of the bone. These ridges are covered by another cylinder and form the haversian canals. At 11 days vascular invasion of the marrow cavity occurs and resorption of the endosteal surface begins. This type of periosteal deposition and endosteal resorption is repeated during and subsequent to embryonic development. The mineralized portion of 10-day chick tibiae cultured for 2 days in modified BGJ medium was compared with 10-, 11-, and 12-day tibiae in ovo. Cultured tibiae were similar in length and calcium content to 11-day tibiae in ovo. The form of mineral deposited in ovo and in culture was the same, namely, aggregates of spherical mineral clusters. Differences in culture included the following: (a) few concentric cylinders were deposited as compared with tibiae in ovo; (b) trabeculae were not arranged in rows and ridges in culture; (c) osteocytic lacunae were restricted to bases of trabeculae rather than uniformly distributed as in ovo; and (d) the endosteal surface of tibiae in culture appeared etched.
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  • 2
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    Planta 146 (1979), S. 203-210 
    ISSN: 1432-2048
    Keywords: Cellulose ; Microfibrils ; Negative staining ; Nicotiana ; Protoplasts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study has been made of the wall fibrils produced by tobacco protoplasts, using scanning electron microscopy in conjunction with negative staining. It has been shown that the fibres seen in scanning electron microscopy correspond to aggregates of microfibrils. These aggregates are only visible where they are lifted clear of the protoplast surface. Negative staining of fixed protoplasts shows that the aggregation of microfibrils into the fibres visible in scanning electron microscopy is probably produced by air-drying. Gentle disruption of microfibrils produces both random broken fragments and bundles of short pieces of fibrillar material about 60 nm in length. This material is present in undisrupted young walls, but not in undisrupted older walls. The microfibrils in young walls seem much more fragile and liable to breakage than those in older walls. These results are discussed in terms of the interpretation of scanning electron microscope images and the mechanism of cellulose microfibril formation by higher plants.
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  • 3
    ISSN: 1432-2048
    Keywords: Nicotiana ; Polysomes ; Protein synthesis ; Protoplasts ; Ribonuclease ; Ribosomes ; Stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyribosomes (polysomes), active in an amino acid incorporation system in vitro, were isolated from tobacco leaf protoplasts. A comparison of polysome profiles indicated that the polysome/monosome ratio is greatly decreased in isolated protoplasts as compared to the intact leaf. In isolated protoplasts, a marked accumulation of ribosomal subunits was also found. The division of protoplasts, as investigated in the 8-cell and callus stages, was associated with a(n) (at least) partial regeneration of polysome profiles characteristic for leaves. Plasmolysis of leaves attached to the plant had no great effect on the polysome profile. However, leaf excision per se resulted in a dramatic loss of polysomes, even when the leaf tissue was floated on water. It is concluded that the isolation of the cell from its normal environment, and not the osmotic stress and associated increase in RNase activity, is the most important factor responsible for the loss of polysomes in isolated protoplasts.
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  • 4
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    Cell & tissue research 200 (1979), S. 409-423 
    ISSN: 1432-0878
    Keywords: Human placenta ; Classification of villi ; Histology ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The classification of human placental villi was reviewed on the basis of material prepared by means of special methods. The material from in situ normal-term placentae was biopsied by aspiration into glutaraldehyde. The classification was made on the basis of light-microscopic observations of semithin sections, reconstructions from serial sections, and scanning-electron micrographs. The peripheral villous tree is roughly divided into stem (ramuli), intermediate and terminal villi. The intermediate villi may be further subdivided as mature and immature types, which are found between the stem and terminal villi. Some of the terminal villi possess a local specialization described as the neck region. The histological characteristics and the branching pattern of each type are described, and the basis of the proposed classification is discussed.
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  • 5
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    Cell & tissue research 204 (1979), S. 147-153 
    ISSN: 1432-0878
    Keywords: Granulocytes ; Lymphocytes ; Monocytes ; Scanning electron microscopy ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Polymorphonuclear leukocytes, e.g., neutrophilic granulocytes, were enriched from heparinized blood by a Ficoll-step-gradient centrifugation procedure. Scanning electron microscopy (SEM) revealed a surface morphology of narrow ridge-like profiles and small ruffles with occasional microprocesses. Mononuclear leukocytes were isolated by centrifugation over a Ficoll-Metrizoat gradient. The lymphocytes showed varying numbers of microvilli of different length, size and shape. B lymphocytes, characterized by their capability of “sheep red blood cell (SRBC)-rosette formation”, displayed a similar surface morphology. Completely smooth lymphocytes, described in the literature as T lymphocytes, could not be detected, although many lymphocytes with few microprocesses were observed. Thus, SEM is not a useful tool for distinguishing between B and T lymphocytes in the peripheral blood of chickens. Monocytes were characterized by prominent membrane-like ruffles, but in some cases they closely resembled granulocytes. An influence of the various separation media on the surface morphology of the isolated cells could not be detected when compared with cells isolated by the buffy-coat method.
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  • 6
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    Cell & tissue research 199 (1979), S. 349-352 
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Mitochondria ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary As seen by scanning electron microscopy, the mitochondrial helix in the developing midpiece of mouse testicular spermatozoa is dextral in direction and consists of spherical mitochondrial units arranged in an orderly array of four units per gyre: three appearing in face view and a fourth hidden from view at the back of the gyre. As the spermatozoa mature, the dextral helix is transformed into a sinistral helix. Its constituent spherical mitochondria either change direction abruptly without changing shape; or having first become semilunar or diamond-shaped, they change direction gradually. Mitochondrial division follows the change in helical pitch producing a double sinistral helix. The spherical (or semilunar/diamond-shaped) mitochondria presumably elongate to form the units of the mature midpiece.
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  • 7
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    Cell & tissue research 201 (1979), S. 129-135 
    ISSN: 1432-0878
    Keywords: Pineal body ; Freeze-fracturing ; Scanning electron microscopy ; Wistar rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional ultrastructure of the pineal body of the rat is described on the basis of freeze-fractured preparations. The pineal capsule consists of irregular cells with very flat and perforated processes. Through these openings, extremely branched canaliculi, extending to almost every pineal cell, communicate with the tissue compartment outside the organ. The pericapillary spaces contain, in juxtaposition with capillaries of the fenestrated type, nerve fibers as well as a flocculent granular and filamentous material of unknown origin and chemical nature.
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  • 8
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    Cell & tissue research 203 (1979), S. 53-64 
    ISSN: 1432-0878
    Keywords: Brain ; Third ventricle ; Rana temporaria ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface specializations of the wall of the third cerebral ventricle of Rana temporaria were investigated with the scanning electron microscope. These specializations can be divided into three types: cilia, large bulbous protrusions, and microvillus-like protrusions. Most parts of the ventricular surface are densely ciliated. In contrast, other regions are either scantily ciliated or devoid of cilia. Four areas of the ventricular surface are studded with numerous large bulbous protrusions. These large protrusions can be divided into two types: One type consists of intraventricular end bulbs of dendrites of secretory neurons. The other type is represented by large cytoplasmic extensions of ependymal cells. In the third ventricle of Rana, microvillus-like surface specializations of ependymal cells are ubiquitous structures. Generally, filiform protrusions of varying length are the predominant type. The microvillus-like specializations are transient structures, the number of which varies according to different physiological states of the ependymal cells.
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  • 9
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    Medical & biological engineering & computing 17 (1979), S. 397-403 
    ISSN: 1741-0444
    Keywords: Articular cartilage ; Impact ; Stress ; Strain ; Energy absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Forty-eight samples of 9 mm diameter articular cartilage and associated subchondral bone from, the tibial plateau of human knee joints were mounted in methylmethacrylate cement and subjected to controlled impact velocities. The controlled velocities provided for the testing of 21 samples at a strain rate of 500 s−1 and 27 samples at a strain rate of 1000 s−1. Data are presented on the energy absorption per unit volume of cartilage in relation to the associated stresses and strains. The data in each of the resultant nine graphs are subjected to a least squares fit to the polynomial $$Y = a_1 X + a_2 X^2 $$ The relevant statistical data for each of the strain rates and for the combined data are presented. While the total energy absorption of the articular cartilage of the knee joint at ambulatory stresses of 0·8 to 6·3 N/mm2 is calculated to be no more than 0·13 to 3·65 J, it is suggested that the compliance of the cartilage of the knee joint together with the incongruity of the tibia and femur are essential features that should be considered in the design of total knee-replacement prostheses.
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  • 10
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    Cell & tissue research 197 (1979), S. 169-173 
    ISSN: 1432-0878
    Keywords: Fourth ventricle ; Ependyma ; Scanning electron microscopy ; Domestic fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface features of the ependymal linings of the fourth ventricle in the fowl were analyzed employing the scanning electron microscope (SEM). On the floor of the median sulcus, each ependymal cell has a solitary cilium, whereas on both sides of the sulcus, cilia are so densely distributed that the details of the underlying cell surface are usually obscured. On the roof of the fourth ventricle, except for the surface of the ciliated groove where numerous cilia are present, the ependymal cells are polygonal in shape, and the center of each cell possesses an aggregate of ten to twenty cilia. Cell surfaces of the choroid tela are entirely covered with delicate microvilli and possess clumped cilia. The ependymal cell surfaces of the area postrema are dome-like in shape. Each ependymal cell has a solitary cilium and shows a smooth surface free of microvilli.
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  • 11
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    Cell & tissue research 203 (1979), S. 283-289 
    ISSN: 1432-0878
    Keywords: Radula ; Tooth formation ; Pulmonates ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The radular teeth are secreted at the posterior end of the radular gland and move slowly towards the buccal cavity where they start to function. Helix pomatia and Limax flavus were examined to determine whether the newly formed teeth already show their definite species specific shape, or whether they are gradually finished and moulded in the radular gland. Scanning electron micrographs of Helix pomatia show that teeth are secreted in the odontoblast region in their final form. Their surface is still uneven at the outset; the same is true for the newest teeth of Limax flavus. Older teeth ready for use have a smooth surface. This change seems to be brought about by secretory activity of the superior epithelium of the radular sac. Air-dried radulae, previously isolated by KOH maceration, show considerable artefacts at their posterior end. Maceration leads to shrinking of the newest teeth, but does not change their contours. The newly secreted but as yet unhardened teeth become greatly deformed during the drying process.
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  • 12
    ISSN: 1432-0878
    Keywords: Fish thrombocyte ; Open canalicular system ; Three-dimensional architecture ; High voltage electron microscopy ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence and the three dimensional distribution of the surface connected canalicular system (SCCS) in thrombocytes of a teleost, Cyprinus carpio, were studied using a transmission electron microscope, a high voltage electron microscope and a scanning electron microscope. When the specimens were fixed routinely in glutaraldehyde followed by osmium tetroxide, numerous electron lucent vesicles and canaliculi were distributed throughout the cytoplasm. As ruthenium red-positive reaction product was observed on the inner surface of the vesicles and canaliculi, these are defined as the SCCS of carp thrombocytes. In the stereo-pair of the photographs of thick sectioned specimens and the plastic reconstruction of serially sectioned thrombocytes, we succeeded in finding the whole structure of the SCCS which is composed of numerous anastomosing canaliculi. Scanning electron micrographs revealed many crater-like depressions throughout the cell surface which seem to be the openings of the SCCS.
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  • 13
    ISSN: 1432-0878
    Keywords: Salamander skin ; Skin capillaries ; Poison gland capillaries ; Microcorrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microcorrosion casts of blood vessels in the skin of the spotted salamander, Salamandra salamandra L., were studied using scanning electron microscopy. The investigated vessels include a subepidermal network of respiratory capillaries and the vessels of poison glands. A hypothesis is proposed, according to which both types of vascular beds possess a common origin. Probable factors involved in the differentiation of the primary netword of the subepidermal vessels in larvae are indicated and speculation concerning the supposed mosaic type of circulation in the capillaries of the subepidermal respiratory bed is presented.
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  • 14
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    Cell & tissue research 198 (1979), S. 129-136 
    ISSN: 1432-0878
    Keywords: Cerebral ventricles ; Ependyma ; Pores ; Subarachnoid space ; Scanning electron microscopy ; Amphibia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy of the caudal end of the roof of the fourth cerebral ventricle in four amphibian species shows that numerous pores occur between the ependymal cells. These pores have diameters ranging from 5–100 μm; they permit bulk flow of cerebrospinal fluid out of the ventricular system into the subarachnoid space.
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  • 15
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    Cell & tissue research 196 (1979), S. 23-38 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Mammals ; Three-dimensional organization ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The adrenal cortex of different mammals was studied by SEM in order to demonstrate its actual three-dimensional organization. In the rat, as well as in the cat and pig, the adrenal cortex appeared as a “tunnelled continuum” of polyhedral cells arranged in plate-like structures (laminae). This laminar arrangement was more evident in the inner fasciculate and reticular zones where the cortex revealed a striking similarity to liver tissue. The polyhedral cells of all cortical zones possessed regular facets populated by small pits, larger invaginations and numerous microvilli with the exception of very short and smooth areas probably corresponding to attachment zones and/or gap junctions. This cellular architecture produced a labyrinthic system of intercellular channels or lacunae in which the capillaries were suspended. The pericapillary areas of this labyrinth contained microvilli, amorphous material, a delicate net of fibrils and occasional cells. The intercellular compartment of this lacunar system was mainly bordered by numerous microvilli arising from endocrine cells. The luminal surface of the capillary wall showed not only irregularly protruding margins (interpretable as endothelial junctions) but also clearly overlapping and flattened endothelial extensions. In all the animals and areas of the adrenal cortex examined, the endothelial wall was provided with abundant clusters of small fenestrations (about 50 nm in diameter) generally arranged in sieve plates. Larger fenestrations were noted mainly in the fasciculate and reticular zones of the cat and pig and occasionally in the rat. A final point related to the nature and significance of sinusoidal fenestrations was the occurrence of irregularly shaped and intracapillary located cells mainly noted in the deeper zones of the fasciculate and reticular zones of the gland. These elements — possessing the surface characteristics of macrophages — were observed, with their irregular and slender evaginations, in close proximity to the large fenestrations in a manner reminiscent of Kupffer cells within the lumen of liver sinusoids.
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  • 16
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    Cell & tissue research 197 (1979), S. 539-543 
    ISSN: 1432-0878
    Keywords: Ventricular surface ; Paraventricular organ ; Domestic fowl ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ventricular surface of the paraventricular organ in the domestic fowl is covered with supraependymal fiber elements. These fibers form a dense network having a web-like appearance and a coarse network of fibers running over the ventricular surface. The dense, web-like networks are mainly distributed throughout the caudal region of this organ, whereas the coarse networks are observed in the rostral region. In addition to these structures, spherical bodies with diameters approximately 2.5 to 6 μm are also encountered.
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  • 17
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    Pure and applied geophysics 116 (1978), S. 690-704 
    ISSN: 1420-9136
    Keywords: Friction ; Pressure ; Temperature ; Water ; Stress ; Gouge ; Joints ; Faults
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract This paper reviews many of the mechanical properties of faulted and jointed rock under pressure and temperature and in the presence of water. At low effective confining pressures (below about 1 kilobar), the friction strength is quite variable and depends on the frictional resistance between gouge particles or asperities and on the dilatancy of the fault. At higher pressures the friction strength is nearly independent of mineralogy, temperature, and rate, at least for rocks whose friction strength is less than the failure strength. Water tends to slightly weaken the fault. The type of sliding motion, whether stick-slip or stable sliding, is much more affected by environmental and mineralogical factors. In general, stick-slip is dominant at high pressures and low temperatures, in the presence of strong minerals such as quartz and feldspar, in the absence of gouge, for lower surface roughness, and perhaps in the presence of water. The microscopic deformation mechanisms are poorly understood. At low temperatures, cataclasis dominates in rocks containing mostly quartz or feldspar, and plastic deformation in rocks containing mostly calcite or platy silicates. At high temperature most minerals deform plastically, producing a greater temperature-and rate-dependence of the friction strength. Glass has been found in some sliding surfaces in sandstone.
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  • 18
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    Calcified tissue international 26 (1978), S. 237-241 
    ISSN: 1432-0827
    Keywords: Epiphyseal chondrocytes ; Freezefracture ; Scanning electron microscopy ; Cell processes ; Membrane particles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 μm diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.
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  • 19
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    Calcified tissue international 25 (1978), S. 75-83 
    ISSN: 1432-0827
    Keywords: Rat ; Fluorosis ; Enamel ; Scanning electron microscopy ; Low temperature incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Sixteen 58-day-old male rats of Wistar strain, with a mean body weight of 179 g, were divided into two equal groups. Each group of eight animals was maintained for 70 days on drinking water, ad lib., containing no fluorine (control group) and 100 ppm of fluorine (experimental group). All specimens examined were obtained from the incisal portions of the incisors. The following types of enamel specimens were prepared for scanning electron microscopy: (1) acid-etched specimens; (2) acid-etched specimens followed by low temperature microincineration; and (3) fractured specimens. The enamel formed during high fluoride exposure showed marked hypocalcification, that is, the crystallite density in the prism core and interprismatic region was lower than that of control animals. The organic substances appeared to increase in these regions. These changes were prominent in the outer and middle enamel layers. Such changes following fluoride administration appear to indicate an inhibition of enamel maturation, that is, an inhibition of the mineral deposition and/or an inhibition of organic matrix withdrawal.
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  • 20
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    Cell & tissue research 187 (1978), S. 525-534 
    ISSN: 1432-0878
    Keywords: Salivary glands ; Insects ; Innervation ; Light microscopy ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the salivary gland of the cockroach Nauphoeta cinerea (Olivier) has been investigated with the use of light and scanning electron microscopy. Light microscopy of methylene blue stained glands reveals the presence of a dual innervation arising from the ventral nerve cord and the stomodeal nervous system; the principal innervation is that from the ventral nerve cord which passes to the gland via the reservoir ducts. Branches of these nerves form a plexus on the acinar surface, the axons of which exhibit swelling at irregular intervals. The presence of this surface plexus and the axonal swellings was confirmed by scanning electron microscopy both in normal glands and in those in which the basal lamina had been removed by means of an HCl-collagenase digestion method. No acinar plexus was seen to be formed by branches of the stomatogastric nerve that were associated with the gland. However, other branches of this nerve were clearly connected with a complex network of multipolar neurones on the surfaces of the anterior regions of both salivary reservoirs.
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  • 21
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    Cell & tissue research 189 (1978), S. 409-433 
    ISSN: 1432-0878
    Keywords: Rete testis ; Human ; Histophysiology ; Chordae retis ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The human rete testis was examined with regard to 1) the number and distribution of entrances of seminiferous tubules, 2) the light microscopic topography and 3) details of the passages as revealed by scanning and transmission electron microscopy. In a newborn 1474 entrances were counted, approximately 50 % entering from the right and 50 % from the left of the central long axis. Three major subdivisions of the rete were distinguished and described: a septal (or interlobular) part represented by tubuli recti, a tunical (or mediastinal) part which is a true network of channels, and an extratesticular part characterized by dilatations (up to 3 mm wide) which we have called bullae retis. In SEM, cylindrical strands running from wall to wall in the tunical and extratesticular rete spaces are a prominent feature. We have called these chordae retis. They are covered by epithelium and are 5–40 μm wide and 15 to more than 100 μm long. They contain a peculiar tissue consisting of central myoid cells in a fibroelastic matrix. The smaller chordae are avascular. In the light of these findings the rete is interpreted as a highly complex myoelastic sponge. Its function is discussed.
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  • 22
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    Cell & tissue research 191 (1978), S. 539-548 
    ISSN: 1432-0878
    Keywords: Frog skin ; Respiratory capillaries ; Capillary networks ; Microcorrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microcorrosion casts of blood vessels in the skin of Rana esculenta L. were examined by means of scanning electron microscopy with particular reference to the subepidermal network of respiratory capillaries. Due to the fact that arteries and veins lie in the deeper layers of the stratum spongiosum of the corium, the respiratory vessels form a morphologically homogeneous network. Functionally, however, this network is subdivided into small areas with a centripetal direction of blood flow. The deep capillary net, situated at the base of the stratum compactum of the corium, is not so dense as the respiratory network and does not directly communicate with it. Alveolar glands of the skin have no effect on the distribution of capillaries in the two networks.
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  • 23
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    Cell & tissue research 187 (1978), S. 105-113 
    ISSN: 1432-0878
    Keywords: Mesonephros ; Lamprey ; Renal corpuscle ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The renal corpuscle of the lamprey mesonephros was studied under the scanning electron microscope. Bowman's capsules with individual spaces are chockshaped sacs closely packed together along a medial artery. The lateral walls of the capsules are apposed to those of neighbouring capsules. Glomerular capillaries from the medial artery extend radially between the apposed walls of neighbouring Bowman's capsules. Bulgings of capillaries into the capsular space are associated with mesangial folds of the capsular epithelium. The transitional zone of the visceral layer with podocytes and the parietal layer of squamous epithelium is bounded by linearly arranged rod-shaped epithelial cells. Apertures of the urinary tubule are lined by cells equipped with a fascicle of cilia.
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  • 24
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    Cell & tissue research 188 (1978), S. 375-388 
    ISSN: 1432-0878
    Keywords: Urinary bladder ; Skin ; Toad, frog ; Water flow ; Na transport ; Vasopressin ; Cytochalasin B ; Microfilaments ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A morpho-functional study of the effects of cytochalasin B (CB) on Na and water transport was made in amphibian epithelia. The functional studies confirmed the dissociation of the natriferic and hydrosmotic effects of vasopressin in toad urinary bladders exposed to CB and showed in addition that the block of the hydrosmotic effect was reversible and could still be induced in epithelia maximally stimulated with the hormone. Scanning electron microscopy revealed that CB, per se, did not alter the apical surface of the bladders. An almost total loss of microvilli of granular cells was seen, however, if CB was associated with vasopressin and an osmotic gradient. The results suggest two points: a) the block of the hydrosmotic flow induced by CB is due to factors beyond the apical membrane; b) microfilaments may be important mechanochemical transducers in the chain of events leading to the hydrosmotic effect of vasopressin.
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  • 25
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    Cell & tissue research 187 (1978), S. 271-280 
    ISSN: 1432-0878
    Keywords: Kinocilia ; Discocilia ; Lanice conchilega ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Ein modifizierter Typ von Kinocilien wurde bei der Aulophoralarve des sedentären Polychäten Lanice conchilega gefunden. Für ihn wird die Bezeichnung „Discocilium” vorgeschlagen. Der einzige strukturelle Unterschied zu konventionellen Kinocilien besteht in der Ausbildung eines Köpfchens. Dieses Köpfchen wird vom distalen Ende des Cilienschaftes gebildet, der zu einer Öse gebogen ist, die von der Cilienmembran überzogen wird. Drei Haupttypen von Discocilien können unterschieden werden: a, Cilien mit geradem Axonem, deren Köpfchen durch eine Anschwellung der Membran entstehen, b, Cilien mit Köpfchen mit seitlichem gebogenem Axonem, c, Cilien, in denen das Axonem eine geschlossene Öse bildet. Die Discocilien sind nach dem verbreiteten 9+2 Filamentmuster aufgebaut. Ihr Köpfchen enthält keine Sekrete, es erscheint elektronenoptisch leer. Aufgrund ihrer Anordnung können zwei Typen von Discocilien unterschieden werden, nämlich isolierte Büschel, besonders am Vorderende, und segmentai angeordnete Cilienreihen. Ein möglicher Bildungsmodus der Discocilien wird beschrieben.
    Notes: Summary A modified type of kinocilia has been found in the Aulophora-larva of the sedentarian polychaete Lanice conchilega. For this newly described cilium type the term “discocilium” is proposed. The only structural difference from usual locomotory cilia is the tip, which possesses a discoidal head. The head is formed from the terminal part of the cilium shaft, which is bent to give rise to a loop-like ring covered by the ciliary membrane. Three types of discocilia can be distinguished: a) discocilia having swollen, bulblike heads with a central straight axoneme; b) discocilia having heads with a curved lateral axoneme and c) discocilia in which the axoneme forms a loop. The internal structure shows the usual 9+2 arrangement of the filaments. The head shows no signs of secretion; it appears structureless in electron microscopical examination. There are two kinds of discocilia arrangements: 1) isolated bunches of cilia especially at the tentacles and in the frontal region, and 2) segmental dorsal rows of cilia. The possible formation of discocilia is described.
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    Cell & tissue research 194 (1978), S. 303-313 
    ISSN: 1432-0878
    Keywords: Cement gland ; Xenopus laevis ; Secretion ; Mucus ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cement gland was studied from stage 17, when the anlage is established, to stage 49, shortly before its disappearance. At early stages, the apical membrane is covered by small microvilli that are more abundant than in the surrounding epiblast cells. Vesicular protrusions along the cell boundaries are also more numerous in the gland cells. When the gland reaches maturity, the apical membranes of gland cells differentiate into two regions. In the cranial, kidney-shaped region, the membranes are very narrow and protrude above the level of cell boundaries. Long and slender villi raise from the surface adjacent to cell boundaries. Apical surfaces in the caudal portion are larger and flattened. Cell boundaries are lined with shorter and thicker surface projections. At these stages, the bordering cells are covered with secretion vesicles. During involution the number of cells is progressively reduced. The area of the caudal portion increases relative to the area of the cranial portion. Apical surfaces become more flattened. Surface projections become much shorter and invade the whole of the apical surface. Bordering cells lose their secretion vesicles and their apical surface becomes ruffled with numerous short wrinkles. The significance of the apical structures and their evolution is discussed.
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    Cell & tissue research 195 (1978), S. 99-109 
    ISSN: 1432-0878
    Keywords: Gills ; Air-breathing organs ; Catfish, Saccobranchus fossilis ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The gill secondary lamellae are generally covered with epithelial cells whose outer surfaces form numerous microvilli. The surface of the primary lamellae is characterised by microridges. A particular type of surface sculpturing seems to be associated with given cell boundaries. Further evidence for the derivation of the air tube and fans which guard its entrance by modification of the basic gill structure has been obtained from both the gross surface architecture and microstructure of the individual cell surfaces. Secondary lamellae are represented by stubby projections which generally have a biserial arrangement. The outer surfaces of the epithelia overlying the capillaries of these respiratory islets are coated with microvilli as in the secondary lamellae. On the other hand, the relatively smooth-surfaced ‘lanes’ between groups of respiratory islets have a microridged surface similar to that of the primary gill lamellae. It is suggested that previous estimates of surface area, and consequently diffusing capacities of the air-breathing organ, have been low in view of the increased surface, due to both their gross and microstructure. Estimates for gill surface area may need very little correction as the spaces between the microvilli and microridges are probably filled with mucus under normal conditions.
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  • 28
    ISSN: 1432-0878
    Keywords: Pineal organ ; Carassius gibelio langsdorfi (Teleostei) ; Photoreceptive cell ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The form and size of the outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi, were observed with the scanning electron microscope. The height of the outer segments measures between 1 and 3 μm and the diameter varies widely from 1.5 to 8 μm. Various forms of outer segments, i.e. a slender type, a dome-like type, a cap-like type and a helical type, were demonstrated. The parallel-oriented filamentous processes of the inner segments have the same length as the outer segments and a diameter of approximately 100 nm; they are projections from the apical border of the inner segment and surround the cone-like outer segments. The processes make a right angle with the lamellar disks. The distance between two processes averages 100 nm. The lamellar disks of the outer segments are oriented at right angles to the modified cilium in the basal part, but the angle often changes in the peripheral part, where the lamellar disks are raised and become parallel to the cilium.
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    Cell & tissue research 191 (1978), S. 389-404 
    ISSN: 1432-0878
    Keywords: Subfornical organ ; Japanese quail, Coturnix coturnix japonica ; Ultrastructure ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface ultrastructure of the subfornical organ (SFO) was investigated in the Japanese quail. The SFO consists of a body and a stalk. The body of the SFO can be divided into rostral and caudal parts. On the rostral part, each ependymal cell possesses a short central solitary cilium; clustered cilia are also occasionally seen. Microvilli are abundant. On the caudal part, cells with a solitary cilium are fewer in number, and clustered cilia are rarely found. Microvilli are not as abundant as on the rostral part. In addition, large bulbous protrusions, tufts of small protrusions, deep funnel-shaped hollows, small pinocytotic invaginations and possible cerebrospinal fluid-contacting axons are sporadically observed on the surface of various regions of the body. Each ependymal cell of the stalk has a wide apical surface. A central solitary cilium, microvilli and other structures are observed more rarely on the stalk than on the body, while clustered cilia are not seen on the stalk. These structures are compared with those of the mammalian SFO and further discussed in relation to the possible dipsogenic receptor function for angiotensin II.
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    Cell & tissue research 193 (1978), S. 35-40 
    ISSN: 1432-0878
    Keywords: Planarian ; Scanning electron microscopy ; Epidermis ; Sense organs ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary The epidermis of D. tigrina was examined using the scanning electron microscope. Both dorsal and ventral surfaces are extremely irregular in contour, as well as being permeated by large numbers of pores. Cilia are restricted to the ventral surface, the auricles and that part of the dorsum adjacent to the auricles. Club-shaped receptors, as well as cilia, were seen in the auricles. The epidermis anteriad to the eyespots is indistinguishable from that covering the remainder of the dorsal surface. Light rays could not enter the eyespot through this rough epidermal surface without becoming diffracted in an irregular fashion. It was therefore concluded that visual image perception is not a function of the planarian eyespot.
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    Cell & tissue research 193 (1978), S. 503-524 
    ISSN: 1432-0878
    Keywords: Cryo-ultramicrotomy ; High-voltage electron microscopy ; Scanning electron microscopy ; Olfactory epithelium ; Respiratory epithelium
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    Notes: Summary High-voltage transmission electron microscopy and cryo-ultramicrotomy together with scanning electron microscopy and some conventional transmission electron microscopy of ultrathin sections have been applied to the mucous surfaces of bovine olfactory and respiratory epithelia. Distal segments of olfactory cilia tend to run in parallel and could be followed over distances up to about 30 μm using high-voltage electron microscopy. This technique and scanning electron microscopy showed that on average 12–13 of such cilia could be observed per nerve ending. After correction for obscured cilia this number becomes about 17. High-voltage micrographs and micrographs made from sections prepared with a cryo-ultramicrotome showed the presence of electron-lucent pockets inside the olfactory mucus. The latter technique also showed that the mucus itself is not fibrous, but rather a continuum varying in electron density. The mucus layer contains various granular structures. Ciliary and microvillar membranes appear thicker with cryo-ultramicrotomy than when the sections are prepared with conventional techniques. The cores of the axonemal microtubules in olfactory as well as in respiratory cilia are darkly stained with this technique. Vesicles present inside the nerve endings are also darkly stained. Dimensions and some other numerical values of interest in olfaction are presented.
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    Bulletin of experimental biology and medicine 86 (1978), S. 1663-1665 
    ISSN: 1573-8221
    Keywords: Scanning electron microscopy ; connective tissue ; collagen fiber ; protorysin ; trypsin
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    Notes: Abstract Samples of tendon and fascia, treated with enzymes possessing amylolytic and proteolytic activity (protorysin, trypsin) were investigated by scanning electron microscopy. Destruction of carbohydrate-protein complexes leads to disappearance of the characteristic morphological features of the collagen fibers. Construction of the collagen fiber was shown to be based on a network of thin anastomosing fibrils, forming a carcass connected with the carbohydrate-protein matrix. It is argued that the reticular structure is a general principle in the structural organization of fibrous connective tissues.
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    Development genes and evolution 181 (1977), S. 31-40 
    ISSN: 1432-041X
    Keywords: Cell migration ; Mesoderm ; Gastrulation ; Scanning electron microscopy
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    Topics: Biology
    Notes: Summary At the end of gastrulation, the lateral mesoderm of amphibian embryos migrates ventrally between the ectoderm and the endoderm. The present study is an examination of the morphology of the leading cells of the mesodermal sheet and of the substratum over which they move (the inner surface of the ectoderm). The cells of the leading edge of the mesoderm are generally round, with very short and narrow flattened projections in the forward direction. These projections do not have a “ruffled” morphology, regardless of whether fixation is carried out before or after the ectoderm and mesoderm are dissected away from the endoderm. The inner surface of the ectoderm is covered with fine (450–500A) filamentous extracellular material and the ectoderm cells sometimes extend cytoplasmic processes (approx. 0.1 μ wide) onto the leading surface of the mesoderm or onto adjacent ectoderm cells. These studies indicate that the morphology of cell migration in amphibians is closer to that seen inFundulus than to that characteristic of chick or mammalian cells.
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    Archives of microbiology 112 (1977), S. 123-126 
    ISSN: 1432-072X
    Keywords: Bandeiraea simplicifolia ; Schizosaccharomyces pombe ; Colloidal gold ; Cytochemistry ; α-Galactomannan-lectin ; Scanning electron microscopy
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    Topics: Biology
    Notes: Abstract Galactomannan was localized by scanning and transmission electron microscopy on the cells and cell walls of Schizosaccharomyces pombe. The markers were prepared from colloidal gold granules labelled with an α-galactopyranosyl-binding lectin isolated from the seeds of Bandeiraea simplicifolia. Part or all of this α-galactomannan was present in the outer layer of the cell wall and was uniformly distributed even on the fission scars.
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    Cell & tissue research 176 (1977), S. 493-504 
    ISSN: 1432-0878
    Keywords: Pancreas ; Acinar cells ; Cell surface ; Dissociation ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The pancreatic acinar cell surfaces have been studied by SEM with a dissection technique and correlated with results obtained by TEM. The SEM results demonstrate characteristic arrangement of microplicae which in some areas are densely packed. In many areas, the microplicae are distributed in such a manner that they create zones with typical geometrical shapes and show a relatively smooth surface. These smooth areas may coincide, as indicated by correlated TEM results, with the limits of intimate contact between adjacent acinar cells which, in turn, represent part of the junctional complex. Another aspect revealed by these SEM preparations concerns the presence of groups of densely packed microplicae, arranged in regular rows and distributed along some grooves and/or infoldings of the cellular surface. On the basis of SEM and TEM information, it is likely that these structures correspond to intercellular (and possibly, in some cases, intracellular) canaliculi which topographically form a kind of extensive microlabyrinthine arrangement running along all the cell sides. One final point revealed by fractured samples concerns the finding of spherical zymogen droplets within the vesicles of the Golgi complex. Because in many scanning images these vesicles appear connected by small openings, it is suggested that they may represent a system of intercommunicating chambers (vacuoles) through which the zymogen droplets can be continuously accumulated and discharged into the acinar lumen.
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    Cell & tissue research 177 (1977), S. 307-316 
    ISSN: 1432-0878
    Keywords: Third ventricle ; Mature monkeys ; Scanning electron microscopy ; Ependyma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface features of the ependymal lining of the third ventricle in mature male and female monkeys have been investigated with scanning electron microscopy (SEM). Broad aspects of third ventricular morphology from three species of monkey are similar regardless of sex. The lateral walls are heavily ciliated whereas the ventral floor and most ventral parts of the lateral walls are not. Clumps of cilia on the lateral walls are so dense that underlying surface details are usually obscured. There is a transition zone between the ciliated lateral wall and nonciliated ventral floor. The floor and lower part of the lateral walls of the third ventricle exhibit a characteristic polygonal pattern upon which surface specializations such as microvilli, blebs and polymorphous membrane protrusions are superimposed. Ependyma of the choroid plexus of the third ventricle also display membrane specializations. Supraependymal cells are more visible in nonciliated regions.
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  • 37
    ISSN: 1432-0878
    Keywords: Blood vessels ; High voltage electron microscopy ; Scanning electron microscopy
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    Notes: Summary The luminal surface features and Junctional complexes from developing blood vessels in the rat central nervous system have been studied by high-voltage electron microscopy and scanning electron microscopy. Developing blood vessels exhibit three types of luminal projections; marginal folds or ridges at Junctional complexes, ridges not at Junctional complexes and microvilli. Both types of ridges are associated with troughs or depressions in the luminal surface of the endothelial cell. Those ridges not associated with Junctional complexes take part in the production of enclosed tunnels in the endothelial cell cytoplasm. Fusion of the external leaflets of Junctional complexes between adjacent endothelial cells occurred, initially, near the luminal surface of the blood vessel with other small fusion sites forming in the direction of the basal lamina secondarily. Further fusion activity to produce the zonula occludens type junction appeared to spread outwards from the smaller fusion sites.
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  • 38
    ISSN: 1432-0878
    Keywords: Pineal organ ; Uroloncha domestica (Aves, Passeriformes) ; Photoreceptor-like cells ; Scanning electron microscopy
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    Notes: Summary In the pineal organ of the lovebird, Uroloncha domestica, bulbous, cup-shaped and elongated outer segments of photoreceptor-like pinealocytes are demonstrated by scanning electron microscopy. These scarce outer segments, 4–11 μm in length, extend into the pineal lumen. The present structural observations speak in favor of photosensitive pinealocytes in the pineal organ of Uroloncha domestica. The relation of the photoreceptor-like pinealocytes to acetylcholinesterase-positive nerve cells and a nervous connection between the pineal and the brain indicate that the pineal organ of this passeriform species may be the site of neuroendocrine and photoreceptive functions.
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    Environmental biology of fishes 2 (1977), S. 131-136 
    ISSN: 1573-5133
    Keywords: Trout ; Behavior ; Interrenal ; Hierarchy ; Stress ; Dominance ; Aggression ; Salmo gairdneri
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    Topics: Biology
    Notes: Synopsis The relationship between standing in a dominance hierarchy and physiological stress was studied in rainbow trout. Individual fish were assigned relative dominance ranks, based on behavioral observations in a large, simulated stream tank. These ranks were compared to histometric measures of interrenal cell activity. Fish, isolated individually in the stream tank had significantly lower levels of interrenal activity than fish from the crowded holding tank. Groups of fish in the stream tank formed stable, linear dominance hierarchies. Interrenal activity correlated inversely with dominance rank, with the exception that top ranking fish had higher activity than expected. Possible cause and effect relationships are discussed.
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  • 40
    ISSN: 1432-0878
    Keywords: Lateral ventricle, rat ; Hydrocephalus ; Scanning electron microscopy
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    Notes: Summary The ependyma of the lateral ventricle of rats with hereditary hydrocephalus was studied using scanning electron microscopy. Normal rats from the same litters were used as control animals. The surface morphology of the lateral ventricle of normal rats corresponded to results reported by other authors. The most prominent changes in the surface morphology of the ependyma of the hydrocephalic rats were seen in the cilia. They were shortened, fewer in number and clumped or matted. The surface of the ependymal cells was flattened and contained small, irregular projections. The number of large supraependymal cells, regarded as neurons, appeared to have diminished in the hydrocephalic rats. The number of supraependymal macrophages was greatly increased in these rats, suggesting the existence of an ependymitis.
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    Cell & tissue research 178 (1977), S. 267-278 
    ISSN: 1432-0878
    Keywords: Ciliated epithelium, frog ; Cilia ; Coordination ; Mucous transport ; Scanning electron microscopy
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    Notes: Summary The palate epithelium of the frog was examined by scanning electron microscopy, light microscopy and high speed cine micrography. The cilia remain stationary for much of the time in the end-of-effective stroke position. Each beat cycle begins with a forwardly-directed recovery stroke lasting about 60 ms, followed by an effective stroke towards the oesophagus lasting about 12 ms. Activity can often be correlated with the presence of mucus, which is carried as strands on the tips of the ciliary effective strokes whilst the recovery strokes move beneath the mucus. Coordination of ciliary activity was very variable; local antiplectic metachrony of the recovery strokes could almost always be seen, and on very active epithelia effective strokes were associated with approximately diaplectic waves (either to left or right), but any particular pattern of coordinated activity was transient and quickly transformed to another pattern. Beating and coordination of these short cilia were compared with those of cilia propelling water.
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    Cell & tissue research 178 (1977), S. 375-384 
    ISSN: 1432-0878
    Keywords: Taste buds ; Fishes ; Neuroepithelium ; Microvilli ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary External taste buds abound on barbels of the adult catfish Corydoras arcuatus. When examined by scanning electron microscopy, they are visualized as a series of punctate, conical elevations projecting from the general surface epithelium. All taste buds were found to be of one type. Both their external and internal surface features could be clearly elucidated on intact barbels and in barbels fractured transversely at various positions along their length. An extensive nerve terminal network penetrates the base of each taste bud. Two populations of elongated cells bearing prominent microvilli project through the central pore at the tip of each bud. One set of microvilli is thicker, longer and more club-shaped than its counterpart. While both are randomly distributed within each central pore, the small, short microvilli appear to outnumber the larger ones. A third population of cells, devoid of any apical microvilli, was also seen in some of the taste buds examined internally. These cells do not project to the external surface and are interpreted as “basal” cells described in previous light and transmission electron microscope studies of taste buds in other vertebrate species. The functional significance of some of these morphological findings is discussed.
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  • 43
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    Keywords: Hypophysis, pars distalis ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
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    Notes: Summary The vascularization of the pars distalis of the hypophysis of the toad, Bufo bufo (L.), was studied by the traditional method of injecting a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further, methyl-methacrylate corrosion casts of the brains were made; the hypothalamo-adenohypophysial region of these corrosion casts was studied with the scanning electron microscope. The results showed that the portal vessels which arise from the median eminence do not supply distinct areas in the pars distalis as is supposed by the point-to-point-hypothesis. The portal vessels enter the ventro-median region of the pars distalis and branch off into a three-dimensional network of the secondary capillary plexus of the pars distalis. The plexus is made up mostly by four- to six-sided meshes. This angioarchitecture guarantees an optimal supply of the glandular cells of the pars distalis with nutritional factors and releasing hormones, on the one hand, and facilitates the removal of the hormones which are released by these cells, on the other hand. The venous drainage of the pars distalis is exerted mainly by two large veins, which bilaterally leave the dorso-lateral region (venous pole) of the pars distalis and by a few small veins, which drain into the wide, sinus-like vessel, which curves around the dorso-caudal region of the pars distalis and joins bilaterally the vena hypophysea transversa.
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    Cell & tissue research 183 (1977), S. 531-539 
    ISSN: 1432-0878
    Keywords: Brain ventricles ; Armadillo ; Ependyma ; Scanning electron microscopy
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    Notes: Summary The scanning electron microscope was used to survey the brain ventricular system of the female armadillo (Dasypus novemcinctus) with emphasis on the third ventricle. The walls of the lateral ventricles, aqueduct, and fourth ventricle are covered by long cilia. In the lateral ventricle, the cilia are arranged in groups; but in the aqueduct and fourth ventricle, they are evenly placed over the cellular surfaces. The ependymal cells of the third ventricle are densely ciliated except for the organum vasculosum and infundibular recess. The non-ciliated luminal surface of these areas has a pebblestone appearance punctuated by numerous microvilli and two types of supraependymal cells.
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    Cell & tissue research 179 (1977), S. 225-234 
    ISSN: 1432-0878
    Keywords: Marginal ruffles ; Fibroblast-like cells ; Scanning electron microscopy ; Transmission electron microscopy ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary LW13K2 cells, a clone of a spontaneously in vitro transformed derivative of embryonic Lewis rat fibroblastic cells, were studied by phase contrast cine-light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ruffles found at the advancing edge of cells grown on glass substrates in vitro form and recede in a period of less than one min if they do not make an attachment of the substrate. If they fail to make an attachment they may form pinocytotic channels near the leading edge as described by Price (1972) and/or collapse, generally backwards, towards the cell body. The ‘spines’ which appear to reinforce the membranous ruffles are the last structures to disappear, and accumulate in an irregular array behind the ruffling edge; this area is behind that in which pinocytosis occurs. In comparison with the sparse numbers of ribosomes found in the trailing edge, they are present in notable concentrations near the leading, ruffling edge of the cell. No membrane vesicles have been found in or near the ruffling edges at the ruffle-spine concentration zone.
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  • 46
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    Keywords: Hypophysis, pars intermedia ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
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    Notes: Summary The vascularization of the pars intermedia of the hypophysis of the toad, Bufo bufo (L.) was studied by injection of a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further methyl-methacrylate corrosion casts of brains were made and the hypophysial region of the corrosion casts was examined with the scanning electron microscope. The results showed that the vascularization of the pars intermedia of the toad hypophysis consists of a single-layered vascular network, which is located on the ventral surface of the pars intermedia. The network is formed by capillaries, which primarily run caudally in a fan-like manner and which show only a few cross-connections. In the rostral region of the pars intermedia this network lies rather superficially, while in the caudal region it slightly penetrates the parenchyma. The vascular network originates from vessels of the neural stalk and from wide capillaries of the rostro-ventral region of the neurointermediate junction. The venous drainage of the pars intermedia is exerted by veins, which leave the caudal region and drain into the veins leaving the venous pole of the pars distalis. The fiat, wide meshed vascular net on the ventral side of the pars intermedia, demonstrated in this study, fits into the concept that the pars intermedia of the anuran hypophysis is under the control of nerve fibers coming from the hypothalamus.
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    Cell & tissue research 185 (1977), S. 279-283 
    ISSN: 1432-0878
    Keywords: Vocal cord epithelium (Human) ; Microridges ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The epithelium of the vocal cord from children and adults is analysed with SEM and TEM. Scanning micrographs show that the apical cell membrane is furnished with microvilli and microridges of various patterns. The function of microridges is discussed in relation to the distribution and retention of mucus on the vocal cord.
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    Cell & tissue research 185 (1977), S. 387-397 
    ISSN: 1432-0878
    Keywords: Osteoclasts ; Resorption ; Bone ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Osteoclasts of the peripheral portions of the endocranial aspect of young rat parietal and frontal bones were studied by scanning electron microscopy of glutaraldehyde fixed, critical point dried specimens. These studies show Osteoclasts to have a much more complicated form than has previously been realised. Extensively branching, elongated, smooth-surfaced cells, which are for the most part elevated above the level of the surrounding bone matrix surface and sometimes above portions of osteoblasts or other osteoclasts, were identified as motile non-resorbing cells. Portions of the former and other entire cells may be embowered in Howship's lacunae, have microvilli on their dorsal surface, and are surrounded by a serrated border of microprojections which have an apparently firm attachment to the matrix surface. Osteoclasts in short term culture show additional free surface ruffles which are not encountered in specimens taken fresh from the animal. No evidence of recruitment of osteoblasts or osteocytes into osteoclasts was found. Disinterred osteocytes retained an ability to migrate from their lacunae on to surrounding bone matrix surface.
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    Cell & tissue research 180 (1977), S. 421-431 
    ISSN: 1432-0878
    Keywords: Ciliated cells ; Trachea ; Radiation effects ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Early effects of ionizing radiation were investigated in an experimental in vitro system using the ciliary cells of the tracheal mucous membrane of the rabbit, irradiated at 30° C and at more than 90% humidity. The changes in physiological activities of the ciliary cells caused by irradiation were continuously registered during the irradiation. The specimens were examined immediately after irradiation electron microscopically. The morphological changes in irradiated material after 10–70 Gy are compared with normal material. After 40–70 Gy, scanning electron microscopy revealed the formation of vesicles on cilia, and club-like protrusions and adhesion of their tips. After 30–70 Gy, a swelling of mitochondrial membranes and cristae was apparent transmission electron microscopically. The membrane alterations caused by irradiation are assumed to disturb the permeability and flow of ATP from the mitochondria, which in turn leads to the recorded changes in the activity of the ciliated cells.
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  • 50
    ISSN: 1432-0878
    Keywords: Hypophysis, neural stalk, pars nervosa ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The angioarchitecture of the neural stalk and the encephalo-posthypophysial portal system of the hypophysis of the toad, Bufo bufo (L.), was studied using three different methods. The neural stalk is mainly supplied by branches of the arteria infundibularis superficialis which form a widemeshed vascular network. Dorsally this network continues into the plexus of the pars nervosa. The vascularization of the pars nervosa is made up of the encephalo-posthypophysial portal system. This portal system consists of a hypothalamic branch (=portion), a mesencephalic and a mesencephalic-bulbar branch (=portion). The hypothalamic branch was found to drain the pars ventralis of the tuber cinereum as well as more dorsal regions of the diencephalon. The mesencephalic-bulbar trunk enters the hypothalamic branch. The resulting common stem of the encephalo-posthypophysial portal vein then curves around the retroinfundibular communicating artery, crosses its ventral side and runs caudally. The secondary capillary plexus of the pars nervosa is characterized by well defined capillary networks which are located at the periphery of the parenchyma of the pars nervosa, thus forming a rostral, dorsal and ventro-caudal net. The central region of the parenchyma of the pars nervosa is supplied only by main branches of the encephalo-posthypophysial portal vein. The venous drainage of the pars nervosa is via the vena hypophysea transversa.
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  • 51
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    Archives of microbiology 109 (1976), S. 9-14 
    ISSN: 1432-072X
    Keywords: Candida utilis ; Saccharomyces cerevisiae ; Colloidal gold ; Cytochemistry ; Mannan ; Plasma membranes ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The β(1→3)glucanase of Basidiomycete QM 806 was used to prepare Saccharomyces cerevisiae and Candida utilis protoplasts. Plasma membranes isolated from S. cerevisiae contained a small amount of mannose and traces of glucose and ribose. Randomly distributed α-mannan was detected by scanning electron microscopy at the surface of prefixed protoplasts using colloidal gold labelled with Concanavalin A as a marker. C. utilis protoplasts were also marked with anti-mannan antibodies. Again the distribution of mannan was random. This experiment indicated also that plasma membrane mannan has the same immunochemical determinants as cell wall mannan. It is hypothesized that mannan is mainly located in the outer layer of plasma membranes.
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  • 52
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    Archives of microbiology 109 (1976), S. 31-35 
    ISSN: 1432-072X
    Keywords: Scanning electron microscopy ; Chlamydomonas ; Cell agglutination ; Cell fusion ; Flagella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A technique has been developed by which mating gametes of Chlamydomonas eugametos can be studied in the Scanning Electron Microscope. A detailed description of the mating process, from the initial flagellar agglutination until the release of free vis-à-vis pairs, is presented. Flagella appear to agglutinate at random points on their surface. This is followed by a rapid increase of the contact area such that they “line-up” tip to tip. Flagella always exhibit a typical position prior to cell fusion. After cell fusion the flagella of a pair separate rapidly while the female have shortened about 33%. In a vis-à-vis pair the plasma bridge has contracted. The observations are interpreted in terms of a specific reorganization of the sexuale aggregate.
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  • 53
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    Cell & tissue research 170 (1976), S. 113-128 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Neurosecretion ; Acipenseridae ; Spawning ; Stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neurohypophyses from sexually mature female sturgeons, Acipenser güldenstädti Brandt, killed before, soon after spawning, and during down-stream migration were studied light and electron microscopically. Ovaries were examined only under a light microscope. A large amount of neurosecretory material (3.5–4.5 arbitrary units) is found in the neurohypophysial “roots” during up-stream migration to spawning grounds. Neurosecretory fibres and their terminals are replete with elementary neurosecretory granules. Side by side with the latter some terminals contain single residual granules and few “synaptic” vesicles. Soon after spawning the amount of neurosecretory material decreases markedly in most individuals (content up to 1–3 units), and elementary granules are few in the fibres and their terminals. The number of residual granules increases, and “synaptic” vesicles are especially numerous. Granulated, disintegrating neurosecretory granules and granule-shadows occur in the preterminal parts of the fibres. The number of pituicytes increases because some “light” tanycytes seem to migrate from the ependymal into the subependymal layer. The restoration of neurosecretory material (reaching again up to 3.5–4.5 units) occurs within a month after spawning. The number of elementary granules increases in fibres and terminals while that of residual granules and “synaptic” vesicles decreases. These changes in the neurohypophysis of females after spawning are due to discharge of great amounts of peptide neurohormones into the general circulation after spawning. Spawning is regarded as a “physiological” stress for these females.
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  • 54
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    Cell & tissue research 170 (1976), S. 145-159 
    ISSN: 1432-0878
    Keywords: Neurogenesis ; Retina ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fixed retinae of chick embryos and chicks of the first week after hatching were fractured and examined with the scanning electron microscope. The matrix cells of the retina proliferate up to the beginning of the second week. The migrating cells are oriented in cell cords. This columnar organization prevails up to the development of the plexiform layers formed as a consequence of the outgrowth of the dendritic and axonal cell processes. Special attention was paid to the differentiation of the ganglion, bipolar and receptor cells, and the radial fibers (Müller cells). Two main morphological patterns are significant for the organization of the retina during neurogenesis: a) the cell to cell contacts of migrating cells and b) the spatial arrangement of Müller cells which could provide guidelines for migration of neuronal elements.
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  • 55
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    Cell & tissue research 174 (1976), S. 129-137 
    ISSN: 1432-0878
    Keywords: Pineal organ, human ; Acervuli ; Scanning electron microscopy ; Transmission electron microscopy ; Electron probe microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135–800 μm) between which clustered groups of globuli (4–14 urn in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125–500 Å in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.
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  • 56
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    Cell & tissue research 170 (1976), S. 1-16 
    ISSN: 1432-0878
    Keywords: Tissue culture cells ; Mycoplasma ; Light microscopy ; Transmission electron microscopy ; Scanning electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The host-parasite relationship of HeLa M cells artificially infected with a bovine species of Mycoplasma was studied by light microscopy, transmission electron microscopy and scanning electron microscopy. The use of morphometry to quantitate some of the findings was explored. The parasites were seen in locations extracellular to the cell surface. The detection of small numbers of organisms by light microscopy was well demonstrated by use of the fluorescent antibody technique. Scanning electron microscopy proved to be an excellent method for revealing the surface details of cell-parasite morphology. Ultra-thin sections showed that the parasites are aligned mostly parallel to the plasma membrane of the host cell but separated by a gap of 10 nm. Morphometry indicated an average of 69 organisms per cell surface occupying 1.7% of the surface area. An increase of 26% in diameter of the HeLa cells, possibly as a result of infection, was observed.
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  • 57
    ISSN: 1432-0878
    Keywords: Axons ; Scanning electron microscopy ; Neurones, afferent ; Nerve regeneration ; Spinal nerve roots
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    Topics: Biology , Medicine
    Notes: Summary Rat dorsal spinal nerve roots were cut and the tip on the ganglionic side of the cut was examined by scanning electron microscopy at 0, 7, 20 and 48 h after operation. Seven hours after cutting, free axonal sprouts had started to protrude from the cut end of the nerve. After 20 h the free sprouts were more profuse than at 7 h but were smaller and had a rougher surface. At both 7 and 20 h many of the sprouts consisted of a stalk 2–7 μm in diameter with a bulbous end 5–20 μm in diameter. A few branching sprouts were seen. At 48 h the sprouts were shrunken with a deeply furrowed surface. The significance of the surface structure of the sprouts is discussed.
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  • 58
    ISSN: 1432-0878
    Keywords: Epididymal epithelium ; Castration ; Androgen-substitution ; Japanese monkey ; Scanning electron microscopy
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    Notes: Summary The caput epididymidis from castrated and androgen-supplemented, castrated Japanese monkeys was observed with the scanning electron microscope. The experimental findings were compared with the normal structures in control animals. The epididymal lumen of control animals was lined by a tall, pseudostratified columnar epithelium possessing long, slender stereocilia which were densely arranged in a tuft-like form. After castration, the epididymal epithelium was decreased in height to one-fifth of controls. The stereocilia were also considerably reduced in length and in number, resulting in a flattened epithelial surface with polygonal boundaries. Frequent projection of a long, single cilium from an epithelial cell into the lumen was also a prominent feature in the epididymal ducts of the castrated animals. Administration of testosterone to the castrated animals resulted in almost complete recovery of the epididymal epithelium as well as regeneration of the stereocilia which regained a tuft-like arrangement.
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  • 59
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    Cell & tissue research 172 (1976), S. 379-388 
    ISSN: 1432-0878
    Keywords: Chitons ; Receptors ; Shell surface ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The shells of the chitons Lepidochitona cinereus, Sypharochiton pelliserpentis, Amaurochiton glaucus and Onithochiton neglectus were examined by scanning electron microscopy. In all species the surface terminations of the megalaesthete and micraesthete organs could be identified lying flush with the shell surface, as well as, lenses of the shell eyes in O. neglectus. Periostracal debris and encrusting diatoms were a usual feature of the shell surfaces. The micraesthete subsidiary caps normally appear featureless, but the megalaesthete apical caps sometimes appear to be perforated. The reasons for this perforate appearance are discussed and it is concluded that it provides no evidence for the normal passage of substances out of or into the megalaesthete.
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  • 60
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    Cell & tissue research 166 (1976), S. 65-70 
    ISSN: 1432-0878
    Keywords: Collagen ; Bone ; Cell culture ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Embryonic and young rat bone cells have been grown in culture and examined in the scanning electron microscope (SEM). Compared with cells fixed in situ and taken directly from the animal, the cultured osteoblastic cells were smoother, flatter and more extensive and showed tighter intercellular contacts. Some matrix is formed in culture and undergoes at least partial mineralization as judged by the accumulation of Ca and P measured by energy dispersive x-ray analysis. Findings concerning the morphology of the collagen arrangement were indecisive. Some superficial cells, free of surrounding matrix, resembled osteocytes in normal in vivo bone. This may indicate that a proportion of the extracellular matrix produced by the cultured cells failed to polymerise into recognizable bone matrix, and that osteocytic morphology is not dependent upon the physical characteristics of the bone matrix.
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  • 61
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    Cell & tissue research 169 (1976), S. 277-287 
    ISSN: 1432-0878
    Keywords: Rabbit gametes ; Cryofractography ; Scanning electron microscopy ; Transmission electron microscopy ; Zona pellucida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rabbit ova fertilized in vitro were prepared for scanning electron microscopy by ethanol-cryofracturing and critical-point drying methods and were also embedded and sectioned for transmission electron microscopy. Study of a region of interaction between sperm and zona pellucida with scanning electron microscopy reveals the latter to be composed of a complex network of fibers interspersed with numerous pores. Transmission electron microscopy of the same region reveals a “typical” homogeneous composition of the zona pellucida. Ultrastructural observations of thin sections passing through the region of sperm-egg interactions or through other regions of the ovum or its investments reveals very little methodological distortion of the various intracellular organelles or matrix. Application of the procedures described provides not only an elucidation of surface detail but also reveals intracellular cytoplasmic information about the same specimen during in vitro fertilization.
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  • 62
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    Cell & tissue research 169 (1976), S. 449-465 
    ISSN: 1432-0878
    Keywords: Bone ; Osteoblasts ; Cell surface ; Cell shape ; Calcitonin ; Parathyroid extract ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neonate rat endocranial osteoblasts were cultured on their bone surfaces in control medium (CC) or medium to which either parathyroid extract (PTE) or calcitonin (CT) had been added for 2, 4, 8 or 24 h. Some were cultured for 24 h in CC, then for 2, 4, 8 or 24 h in either CT or PTE medium; or for 24 h in PTE, then for 2, 4, 8 or 24 h in either CC or CT; or 24 h in CT and 2, 4, 8 or 24 h in CC. The dorsal ruffling of the cells in CC was found to be suppressed by later culturing with PTE and the disoriented cells reorganized to form arrays of parallel cells. The effects of PTE were also reversed by CC or CT: the osteoblasts in the second culture (CC) lost elongation and order, and proceeded through a proliferative phase before exhibiting the ruffling form similar to a single CC 24 h culture. PTE-cultured osteoblasts showed an increase in cell overlap and contact so that a more competent barrier was formed separating the bone from the medium. In control or CT medium, however, intercellular gaps were greater than in vivo.
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  • 63
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    Cell & tissue research 166 (1976), S. 91-100 
    ISSN: 1432-0878
    Keywords: Kidney (rat) ; Uriniferous tubule ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of luminal surface of clearly identified portions of uriniferous tubules has been studied by scanning electron microscopy to elucidate some controversies concerning the topography of certain surface formations. The results show a characteristic pattern of the luminal surface in the region of Henle's loop, which was assumed by previous authors, to belong to the collecting tubule. Furthermore it is demonstrated that no cilia are present within the terminal portion of the collecting tubules.
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  • 64
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    Cell & tissue research 174 (1976), S. 499-518 
    ISSN: 1432-0878
    Keywords: Fibroblast ; Human ; Transmission electron microscopy ; Scanning electron microscopy ; Aggregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The different stages during aggregation of diploid human skin fibroblasts have been examined by transmission and scanning electron microscopy. As a result of aggregation, fibroblasts form a complex tissue configuration. Numerous intercellular junctions can be observed, while the cells remain polygonal and do not develop an organised intracellular cytoskeleton. Cell division occurs only rarely. After aggregation, signs of progressive auto-digestion develop. Adhesion to a substrate results in outgrowth of the cells and monolayer formation, even when extensive cell damage had occurred. The morphology of fibroblasts in aggregates and in the monolayers, from which they were derived, is compared and the contribution of the aggregate system to the study of fibroblast behavior is discussed.
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  • 65
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    Cell & tissue research 166 (1976), S. 299-314 
    ISSN: 1432-0878
    Keywords: Renal glomerulus (Rat) ; Endothelial cells ; Blood capillaries ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rat kidney was perfused with saline and glutaraldehyde, treated with Murakami's tannin-osmium impregnation method, ethanol-freeze cracked and dried by the critical point method. Gold-palladium evaporated specimens were observed in a field-emission scanning electron microscope. The glomerular filtration membrane, fractured in different planes was observed with the following results: 1. Adjacent pedicles originate from different podocytes. No interpedicular bridges of apparent cytoplasmic nature could be found. 2. The basement membrane, in grazing fractures shows a horizontally layered architecture. 3. The attenuated endothelial sheet (lamina fenestrata) is divided into compartments, which we suggest should be called “areolae fenestratae”, by cytoplasmic crests radiating from the nucleated portion of the endothelial cell. A crest also occurs along the cell margin, which contacts a similar crest at the margin of the adjacent cell. 4. The pores in the areolae fenestratae are variable in size (30−150 nm diameter). A knob-like projection from the apparently naked basement membrane is found in a portion of the pores. 5. Numerous microvilli may occur on the endothelium. Some of them anastomose and fuse with one another to form a net whose meshes appear identical with the endothelial pores. Domes and shelves formed of a fenestrated cytoplasmic sheet also occur above the ordinary level of the endothelial lining. A hypothesis implicating microvilli in partial renewal of the endothelial sheet is proposed. This study was assisted by Mr. K. Adachi of the SEM Laboratory at the Niigata University School of Medicine.
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  • 66
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    Cell & tissue research 167 (1976), S. 425-438 
    ISSN: 1432-0878
    Keywords: Scanning electron microscopy ; Crystalline lens ; Microphthalmos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface features of cortical fibers from lenses of normal adult rats and microphthalmic rats of the Browman strain have been studied by scanning electron microscopy. In the normal lenses, superficial cortical fibers follow a straight course from inner to outer pole whereas the deeper cortical fibers, while straight near the poles, pursue an undulating or zig-zag course at and near the equator. Almost all of the fibers are hexagonal in cross section and all fibers throughout their entire length are bound by interdigitating processes at each corner of the hexagon to corners of two adjacent fibers. Some fibers are also affixed by a single row of ball and socket junctions located on their broad outer and inner surfaces. Lens fibers from Browman rats display both minor and major abnormalities. These included segmentation, formation of incisures and lateral protrusions, corrugation and villous-like alteration of the broad fiber surface and development of parallel ridges on broad surfaces in a basket-weave pattern.
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  • 67
    ISSN: 1432-0878
    Keywords: Retina ; Haplochromis burtoni ; Photoreceptor cells ; Light-adaption, dark-adaption ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The photoreceptor layer in the retina of Haplochromis burtoni (Cichlidae, Teleostei) was studied by scanning electron microscopy. Three types of receptors were identified: rods, single-cones and double-cones. The three-dimensional arrangement of these photoreceptors is described in the light- and dark-adapted retina. The surface of the inner segment of the photoreceptor cells displays fine vertical fissures which give rise to slender processes. These so called calycal processes which are of different lengths in rods and cones, surround the beginning of the smooth-surfaced outer segment. The myoid, the contractile part of the receptor, which is located beneath the ellipsoid, was examined in the single-cones of the dark-adapted retina. It is a slender structure with surface infoldings. The myoid, studied by transmission electron microscopy, contains bundles of parallel myofilaments, which are thought to be contractile.
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  • 68
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    In:  New York, 571 pp., Wiley, vol. 5, no. XVI:, pp. 1-14, (ISBN 0-89871-521-0)
    Publication Date: 1976
    Keywords: Structural geology ; Textbook of geology ; Stress ; Geol. aspects ; Crustal deformation (cf. Earthquake precursor: deformation or strain)
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  • 69
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    In:  New York, Springer, vol. 1, no. 1, pp. 65-66, (ISBN 0 340 76405 8)
    Publication Date: 1976
    Keywords: Stress ; Textbook of geophysics ; Textbook of geology ; Elasticity
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  • 70
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    Cell & tissue research 157 (1975), S. 457-465 
    ISSN: 1432-0878
    Keywords: Pecten oculi ; Pigeon ; Surface ; Function ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A scanning electron microscopic study of the pecten reveals the rib-like character of the pectinal folds, the nature of their connections with the base and bridge of the pecten as well as the presence of interconnections between the bundles of superficial collagenous fibres. It has been suggested that the pecten may have a mechanical significance, namely protection of the retina from the excessive movements of the vitreous humour. The relationship between the superficial membrane of the folds which is continuous, the intercellular spaces and the process of diffussion has also been discussed.
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  • 71
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    Cell & tissue research 159 (1975), S. 73-80 
    ISSN: 1432-0878
    Keywords: Osteoblasts ; Collagen orientation ; Parietal bone ; Rat, Rhesus monkey ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bone was removed from the calvaria of anaesthetized 70 g rats or freshly killed young monkeys and the fibrous periosteum dissected off the inner, formative surface under 0.15 M cacodylate buffer. The bone and undisturbed osteoblasts were fixed in 3% glutaraldehyde in the same buffer for 24 to 48 hours, critical point dried and coated with evaporated carbon and gold for scanning electron microscopy (SEM). Fields of osteoblasts were photographed and chosen cells dissected off the osteoid using a tungsten needle. The control of the dissection was made possible by the use of a system of real-time stereo TV-speed SEM. The fields were rephotographed and the orientations of the osteoblasts were compared with that of the underlying collagen fibres. 62% of all osteoblasts lay with their long axes within 15° of the collagen fibre orientation below and 80% within 30°. Montages of large areas of osteoblasts were also made, and then compared with ones of the same area after the cells had been stripped off on adhesive tape. In general, the orientation of the collagen tended to be the same as the cell that formed it. Collagen fibres below cells at the periphery of a domain sometimes had the orientation of the cells in the adjacent patch. It is not possible to determine whether the cells controlled the orientation of the collagen, or vice versa, from this experiment, but other SEM evidence suggests that the collagen orientation in hard tissue matrices depends on the freedom of cells to move with respect to the matrix surface.
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  • 72
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    Cell & tissue research 159 (1975), S. 233-243 
    ISSN: 1432-0878
    Keywords: Odontoblasts ; Predentine ; Dentine ; Calcification ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts. Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at -70° C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron microscopic levels.
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  • 73
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    Cell & tissue research 160 (1975), S. 399-410 
    ISSN: 1432-0878
    Keywords: Lung ; Frog ; Alveolar epithelium ; Mucus layer ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning and transmission electron microscopy were used to study the inner architecture of the frog lung. In some specimens the alveolar surface mucus layer was removed to permit the examination of underlying features. The inner surface of the frog's lung is covered by a layer of microvilli belonging to only one type of epithelial cells. The boundaries of these epithelial cells are demarcated by small ridges. Different degrees of lung expansion cause variations of the surface topography. The morphology of certain surface features is examined in detail. Several methods of drying the specimens are compared.
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  • 74
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    Cell & tissue research 161 (1975), S. 329-341 
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Boar, bull, ram ; Surface ultrastructure ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé La morphologie comparée des spermatozoïdes éjaculés de Verrat, Taureau et Bélier a été étudiée au microscope à balayage. Le sperme lavé est fixé dans le glutaraldéhyde ou le mélange acide picrique-formaldéhyde-glutaraldéhyde. Les échantillons sont le plus souvent désséchés par la méthode du point critique (Fréon) sur un filtre et aussi dans l'air sur une lamelle de verre. La tête des spermatozoïdes de ces trois espèces présente la même forme en pagaie aplatie formée de trois régions principales: les deux segments, antérieur, entouré d'un épaississement marginal, et équatorial de l'acrosome et la région postacrosomique. La plupart des differentiations de la lame postacrosomique décrites en microscopie électronique à transmission sont visibles à travers la membrane plasmique, particulièrement après dessication à l'air. La morphologie superficielle du cou et des différentes parties du flagelle est aussi observable. Des différences spécifiques sont mises en évidence: chez le verrat seulement, par exemple, la surface de l'acrosome apparaît granuleuse, et aucune bordure antérieure dentelée de la lame postacrosomique n'est visible. La microscopie à balayage permet d'observer les grands traits et de fins détails de la morphologie superficielle d'un échantillon de sperme et aussi d'étudier les effects de traitements sur des spermatozoïdes (congélation, extraction de l'acrosome).
    Notes: Summary The comparative ultrastructure of ejaculated boar, bull and ram spermatozoa is studied by scanning electron microscopy. After washing, the spermatozoa are fixed in glutaraldehyde or in picric acid-formaldehyde-glutaraldehyde mixture. Samples are prepared either by critical point drying (Freon) on Millipore filters or by air drying on glass cover slips. In all the species studied, three regions may be distinguished in the paddle-shaped head of the sperm: an anterior segment (surrounded by the marginal thickening) and an equatorial segment constituting together the acrosome, and the postacrosomal region. Most of the feature of the postacrosomal lamina described in transmission electron microscopy are visible through the plasma membrane, particularly after air drying. The surface morphology of the neck and of the different segments of the flagellum is also evident. Some species differences are encountered, e.g. rough surface of acrosome and absence of serrations in postacrosomal lamina of boar spermatozoa only. The techniques employed result in good general morphology and fine resolution of surface detail of the sperm samples; they also permit analysis of spermatozoa treated by freezing or submitted to acrosomal extraction.
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    Cell & tissue research 163 (1975), S. 125-132 
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    Keywords: Bovine subcommissural organ ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The bovine subcommissural organ was studied by using scanning electron microscopy. The most prominent finding was the existence of protruded and dilated endings of the ependymal cells. The majority of these cells were ciliated with two or more cilia; only a few unciliated cells were seen. Some pore-like structures were also seen on the surface. From the functional point of view, the most interesting finding was an amorphous heterogeneous material on the subcommissural ependyma. Especially in the caudal part of the organ this material accumulated in abundance. No real filamentous structures such as Reissner's fibre could be seen, however, it was assumed that the heterogeneous material corresponds to this formation. No supraependymal neurones were demonstrated.
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  • 76
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    Cell & tissue research 163 (1975), S. 313-325 
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    Keywords: Neurogenesis ; Cerebral cortex ; Scanning electron microscopy
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    Notes: Summary Fixed cerebral vesicles of mouse foetuses were fractured and examined with the scanning electron microscope. This method provides a study of the three dimensional developmental features of the pseudostratified columnar epithelium up to the formation of the early cortex plate. Matrix cells are a cell population of homogeneous shape, however, mitotic cells are easily identified by their spherical form. The external surface of the brain is formed by the closely packed end feet of these cells covered by a basal membrane. The formation of the cortical plate is the result of a continuous cell migration in columnar arrangement towards the pia. Glioependymal cells extend along the whole brain wall and most likely provide guidance for the migrating cell cords. The formation of the so-called migratory zone is a consequence of the growth of the basal and the horizontal prolongations of emigrating cells. The significance of the cell to cell contacts for the neuronal migration processes is discussed.
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    Cell & tissue research 159 (1975), S. 379-385 
    ISSN: 1432-0878
    Keywords: Compound eye ; Musca domestica ; Ommatidium ; Distal retinula ; Scanning electron microscopy ; Corneal lens ; Corneal pigment cell ; Pseudocone ; Semper cell ; Basement membrane
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    Topics: Biology , Medicine
    Notes: Summary The distal aspect of the housefly ommatidium was surveyed by the scanning electron microscope. Attention was directed to the somal eminence of the superior central cell and the lens to large pigment cell junction. The underside of each lens facet exhibits six hexagonally arranged incisures. Into each of these indentations are fitted several large pigment cells. This hexagonal indentation appears to be a tenacious anchorage. Two corneal pigment cells laterally encircle the pseudocone and at their proximal extension they enclose the Semper cells and neck of the retinula. The somal eminence of the superior central cell is about 10 μm from the base of the corneal pigment cell enclosure. Micrographs were used to construct a diagram of the ommatidium above the basement membrane. Suggestions are made as to the functional correlates of the observed ommatidial structures.
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  • 78
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    Keywords: Hypothalamo-adenohypophysial region Bufo bufo (L.) ; Portal vessels ; Methyl-methacrylate casts ; Light microscopy ; Scanning electron microscopy
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    Notes: Summary The vascularization of the hypothalamo-adenohypophysial region of the toad Bufo bufo (L.) (Amphibia, Anura) was studied by means of light- and scanning electron microscopy. Special attention was given to the portal vascular system of the median eminence and the pars distalis. Course and arrangement of these vessels are described.
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  • 79
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    Cell & tissue research 162 (1975), S. 377-385 
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    Keywords: Globiferous pedicellariae ; Psammechinus miliaris ; Microvilli ; Chemoreceptor ; Scanning electron microscopy
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    Notes: Summary The globiferous pedicellariae of Psammechinus miliaris are described. Two fixation methods giving minimal distortion and rapid tissue hardening were adapted for soft tissue preparation for scanning electron microscopy. The pedicellarial valves are covered by a microvillous epithelium. The outer valve epithelial microvilli overlying red spherulocytes in the epidermis are characterized by a filament matrix radiating out from each microvillus. These microvilli may function in epidermal absorption of organic solutes. The inner valve microvilli are more densely packed and the filament matrix is absent. Ciliation is confined to the inner valve surface where the cilia are concentrated to form a distal sensory pad and sensory hillock. Behavioural evidence suggests a chemo- and mechanosensory role for the inner valve surface.
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    Cell & tissue research 164 (1975), S. 371-385 
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    Keywords: Kupffer cell ; Endothelial cell ; Sinusoid ; Liver ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The surface ultrastructure of Kupffer cells in the rat liver has been studied by scanning electron microscopy (SEM). The results demonstrate that Kupffer cells are both significantly different and clearly distinct from endothelial cells. Kupffer cells have neither pores (and/or “sieve plates”) nor fenestrations, all of which are present in endothelial cells. They possess a stellate shape, and only indirectly, with slender and irregular evaginations, contribute to the lining of the sinusoidal wall. Furthermore, the luminal surface in some areas contains a large population of short microvilli, microplicae and invaginations. These elements form a kind of microlabyrinth which may correspond to the “worm-like” structures described by transmission electron microscopy (TEM). In the present study, transition forms between endothelial and Kupffer cells were never found. On the contrary, considering the highly fenestrated nature of the endothelial cells, the Kupffer cells may, by ameboid movements, easily cross the overlapping barrier of the sinusoid and protrude into the lumen. Thus, acting as activated macrophages, the Kupffer cells might function to prevent the entrance of foreign material into the tissues of the liver through the fragile and highly fenestrated endothelium. Finally, the topographical reconstruction of the sinusoid by correlated SEM and TEM studies demonstrates that Kupffer cells, with their protruding cytoplasm and ability to extend into the lumen of the sinusoid, may actually change the caliber of the vessel, and thus function as a “sphincter” which causes a temporary arrest of the blood flow when the diameter of the sinusoidal lumen is reduced.
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  • 81
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    Keywords: Neuromuscular junctions ; Appendicularia (Oikopleura dioica) ; Connective tissue fibrils ; Scanning electron microscopy
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    Notes: Summary Critical point dried and fractured appendicularia of the species Oikopleura dioica have been examined in the scanning electron microscope. The dorsal nerve cord with ganglion cells and peripheral nerve fibres could easily be observed. Thick peripheral nerve fibres leave the nerve cord as bilateral pairs at constant intervals along the tail. Most of these fibres branch from the naked nerve cord, but some evidently originate in ganglion perikarya bulging out from the nerve cord itself. These paired peripheral nerves always have elaborate end-arborizations on the medial surface of the lateral muscle cells. They are accordingly interpreted as motor axons. Some thinner peripheral nerve fibres originate at irregular intervals from both the nerve cord and the ganglion cells. Due to the numerous extracellular fibrils that connect the bilateral layers of the epidermal fins and the muscle cells to each other, these thin nerve fibres can seldom be traced to their termination. A few ones can, however, be traced ventrally between the notochord and the muscle cells and seem to end in singular bulb-like expansions. Clusters of synaptic vesicles are present in transmission electron micrographs of such nerves, and they are accordingly believed to carry efferent impulses. The extracellular fibrils are arranged in a highly ordered pattern with thick bundles crossing the gap between the structures to be interconnected and with numerous radiating insertions on the surface of the tissues.
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    Cell & tissue research 164 (1975), S. 467-471 
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    Keywords: Pancreas ; Islets ; Scanning electron microscopy
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    Notes: Summary The surfaces of isolated pancreatic islet cells were studied with the scanning and transmission electron microscopes. Islets were isolated from the pancreas of Wistar rats by collagenase treatment and were incubated either in glucose-free medium or in 300 mg% glucose for one hour. Immunoreactive insulin (IRI) in the media of both control and experimental preparations was assayed. Islets were then transferred to 4% glutaraldehyde, buffered with cacodylate, pH 7.4, and prepared for scanning and transmission electron microscopy. Cell masses average 200 μ in diameter. Alpha cells appear pyramidal in shape, are about 8 μ in diameter and appear in groups. Beta cells are round or oval in shape and have an average diameter of 10 μ. Glucose stimulation raised the IRI value tenfold and increased the number of blebs and other surface irregularities per unit area of beta cell surface. Comparison with transmission electron micrographs suggests that the blebs are related to the process of emiocytosis.
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    Cell & tissue research 163 (1975), S. 29-44 
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    Keywords: Spermatozoa ; Capacitation ; Uterus ; Acrosome Reaction ; Scanning electron microscopy
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    Notes: Summary The surface morphology of rabbit spermatozoa, fixed in situ (female reproductive tract) and prepared for scanning electron microscopy by critical point drying, was studied for as many as 36 hours post coitum. The findings demonstrate that 1) spermatozoa in the reproductive tract following coitus exist as a heterogenous, morphological population and 2) with time, shifts within this population from one predominant morphology to another take place. In the fresh ejaculate, most spermatozoa have intact surfaces free of membranous disruptions. With time, a process of labilization (denudation) of the membranes covering the acrosomal region occurs in a progressively larger proportion of spermatozoa. The labilization originates by a process of vesiculation and/or vacuolation and leads to the appearance of a series of small fenestrations or perforations of the surface membranes. The perforations coalesce, and gradually larger areas of the surface membranes are eroded such that by 15 hours post coitum, the outer acrosomal membrane, as well as other acrosomal areas, are to varying degrees, directly exposed to the uterine milieu. Secretory granules, picked up by cilia and transferred to the spermatozoa become localized over the acrosomal region shortly after coitus. The possible significance of these time-dependent, morphological events with the phenomena of capacitation and the “true” and “false” acrosome reactions are discussed.
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    Cell & tissue research 163 (1975), S. 411-413 
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    Keywords: Cuticle ; Laminae ; Arthropod ; Scanning electron microscopy
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    Notes: Summary Examination of etched pyramids of decapod crustacean cuticles with the scanning electron microscope indicates that laminae are continuous around the angles of the pyramids. This observation is in direct contrast to the result expected on Bouligand's (1965, 1971) hypothesis and suggests that laminae may be real structures.
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    Cell & tissue research 148 (1974), S. 69-82 
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    Keywords: Ultimobranchial glands ; Anuran larvae ; Metamorphosis ; Ultrastructure ; Scanning electron microscopy
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    Notes: Summary The fine structure of ultimobranchial (UB) gland cells from Rana temporaria larvae 48 h after hatching until the completion of metamorphosis is described. A single UB cell type is present, believed to be the characteristic C cell, in which secretory granules are first detectable in 8 day post-hatching larvae. These secretory granules show an intimate association with lipid droplets. Unusual membranous and crystalloid inclusions, which may represent yolk platelets, are found in UB glands of very small larvae. The significance of a range of UB organelles is discussed and some scanning electron micrographs presented. This report is believed to be the first published ultrastructural and scanning electron microscope study of larval anuran UB glands.
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    Cell & tissue research 150 (1974), S. 389-397 
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    Keywords: Choroid plexus ; Human fetus ; Modifications during development ; Scanning electron microscopy
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    Notes: Summary The ultrastructural organization of the human fetal choroid plexus was assessed with scanning electron microscopy. The membranous modifications of choroidal ependymal cells differ remarkably between 11 and 20 weeks of intrauterine development and suggest a variable functional capacity at different times of ontogenesis. Based upon existing data coupled with the ultra-architectural organization of cilia, clavate and linear microvilli are seen with scanning electron microscopy, a multiple functional role is hypothesized for choroidal ependymal cells.
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    Cell & tissue research 153 (1974), S. 151-165 
    ISSN: 1432-0878
    Keywords: Taste buds ; Fishes ; Chemoreceptors and Mechanoreceptors ; Scanning electron microscopy
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    Notes: Summary Within the epithelium of the head gut of the sword-tail (Xiphophorus helleri Heckel) there are three types of taste buds that can be identified with certainty in the scanning electron microscope. The breathing valves, which are situated behind the mouth region, bear relatively high epidermal papillae in which type I taste buds can be found. The middle region of the head gut is mostly occupied by low epidermal papillae containing type II taste buds. Type III taste buds are present within the metabranchial head gut; they never rise above the normal level of the epithelium. Taste buds of each type show two kinds of receptor villi within their receptor areas: tall villi (about 1,5×0,5 μm) and small villi (about 0.5×0.2 μm). A few tall villi belonging to solitary chemosensory cells are situated between the superficial epithelial cells of the tongue. In addition, the surface of the epidermal cells shows a delicate microridge system.—It is postulated that the taste buds of different types serve different functions: Taste buds within epidermal papillae may act both as chemoreceptors, and mechanoreceptors. Taste buds that never rise above the normal level of the epithelium perhaps act predominantly as chemoreceptors.
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    Cell & tissue research 148 (1974), S. 83-96 
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    Keywords: Sharpey fibre bone ; Collagen orientation ; Mineralization ; Mammals ; Scanning electron microscopy
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    Notes: Summary Sharpey fibre bone specimens from cranial sutures and muscle attachment sites of rhesus monkeys and rats, and tooth sockets of several mammals (man, rhesus monkey and rat specimens mainly) were fixed, and either dried by critical point drying or freeze drying, or made anorganic with 1,2 ethane diamine or sodium hypochlorite, washed and airdried. The bone was examined by scanning electron microscopy. The packing density of the extrinsic fibres affected their cross sectional shape, the well separated fibres being the most uniform. Long parallel rows and groups of extrinsic fibres were observed. The fibre units that made up the Sharpey fibre bundles were sometimes distinct and mineralized as units. Mineralization was generally similar to the varied patterns encountered in root cementum. The diameters of the extrinsic fibres were similar at all sites and in all species; those in socket bone differed little from those in cementum. The intrinsic fibre orientation, although constant over fairly large areas, showed no consistent relation to the direction of entry of the extrinsic fibres. We would like to thank Mrs. E. Bailey and Mr. P. S. Reynolds for technical assistance.
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    Cell & tissue research 147 (1974), S. 149-156 
    ISSN: 1432-0878
    Keywords: Sensorysur face ; Tentacles ; Sea anemones ; Corals ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Examination of the sensory surface of the tentacles of sea anemones and corals prepared by the Freon critical-point method has revealed three primary structures: ciliary cones consisting of a cilium surrounded by a cluster of shorter stereocilia, single long cilia, and microvilli. The ciliary cones occur on, and the single cilia and microvilli occur both on and between, the nematocyst- and spirocyst-bearing regions of the tentacles. The similarity of the anthozoan ciliary cones to the ciliary sensory structures in the lateral line, and the auditory and vestibular organs of vertebrates is noted and the possible functional significance of the coelenterate structures is discussed.
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    Cell & tissue research 147 (1974), S. 163-167 
    ISSN: 1432-0878
    Keywords: Articular cartilage ; Scanning electron microscopy
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    Notes: Summary Samples of articular cartilage from four different human joints were obtained at surgery. Serial scanning electron micrographs taken at a magnification of 1000× were used to reconstruct an 0.25 mm2 area of articular surface. Within these given areas both normal and degenerated portions were seen. This study supports the concept that the surface morphology of articular cartilage varies from joint to joint and from area to area within a joint. This information should be useful for the interpretation of light and electron micrographs, as well as histochemical and biochemical data.
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  • 91
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    Keywords: Ciliated cells ; Mucous membranes ; Trachea ; Heat exposure ; Scanning electron microscopy
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    Notes: Summary The mucociliary system of the respiratory tract is easily influenced by temperature — and humidity variations in the surrounding air. A series of functional in vitro experiments on heat-exposed rabbit trachea has been performed. The present investigation deals with the corresponding morphological changes of tracheal surface structures after exposure to temperatures between 40°C and 50°C and at a constant humidity of approximately 90 per cent. The following pathological findings were observed at a temperature of 42°C: 1. Fusion of cilia in their distal ends after 20–45 min., 2. appearance of submembranous vesicles without visible matrix after 45–165 min., 3. disappearance of vesicles and a definite deterioration of ciliary structures after 165 min.
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  • 92
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    Keywords: Saccus vasculosus ; Rainbow trout ; Osmoregulation ; Infundibular recess ; Scanning electron microscopy
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    Notes: Summary Injection of a saccus vasculosus homogenate from sea water adapted rainbow trout into the third brain ventricle of fresh-water rainbow trout increased the survival time of the latter in sea water of high salinity. This indicated an active role of saccus vasculosus in osmoregulation. Autoradiographic analysis of brains from injected fish that had received a saccus vasculosus homogenate from sea water adapted specimens, in which the coronet cells of saccus vasculosus had previously been labelled with 3H-glucoseamine, revealed actual incorporation of labelled material into brain cells, especially in the hypothalamic region. The intracellular distribution of labelled material in the coronet cells of rainbow trout labelled with 3H-glucoseamine strongly indicates that such material represents a secretory product; it is therefore probable that the observed incorporation of label into brain cells of injected fish actually reflects normal processing of material secreted from the coronet cells. In the scanning electron microscope, the inside wall of the third brain ventricle of the rainbow trout was in many areas found to be covered with cilia. These apparently serve to keep liquor in circulation. The observation, both in injected and control animals, of free globules among these cilia supports the idea of an intra-ventricular transport of detached coronet cell material to the infundibular recess, as indicated by the autoradiographic analysis.
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    Cell & tissue research 148 (1974), S. 111-125 
    ISSN: 1432-0878
    Keywords: Liver ; Sinusoids ; Kupffer cells ; Spaces of Disse ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The inner surface of sinusoids and adjacent hepatocytes have been examined by scanning electron microscopy. The endothelial cells lining the sinusoids show large numbers of fenestrations which vary greatly in size and arrangement. Some are very small (0.1 μm) and arranged in clusters; others that are much larger (∼1.0 μm) are subdivided by slender strands of cytoplasm. At sites where the larger fenestrae are present it is evident that the endothelial lining of the sinusoid is double. This may represent a kind of structural assurance against complete breakdown of what seems to be a very thin and fragile endothelial wall. Junctions between adjacent endothelial cells have not been found in these preparations. The open continuity of the sinusoid is occasionally interrupted by slender extensions of cells morphologically distinct from the thin fenestrated endothelial cells. These possess a characteristically textured surface and are thought to represent stellate Kupffer cells. The SEM images describe the subendothelial Spaces of Disse as being larger and as having more extensive ramifications than is generally evident from transmission micrographs. The space, limited on one side by the hepatocyte with numerous microvilli and on the other by endothelial cells, appears actually to be only part of an extensive labyrinth of intercellular channels. These connect the more discrete Spaces of Disse and extend into the narrower spaces between the hepatocytes. The total effect of this system is to expose the greater part of the liver cell surface to the blood filtrate. Microvilli populate the hepatocyte surfaces except for narrow margins which border the bile canaliculi. Whether their presence coincides with the adsorbing surfaces and their absence with secreting surfaces can be decided best by experimental studies.
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    Cell & tissue research 149 (1974), S. 301-312 
    ISSN: 1432-0878
    Keywords: Graafian follicle ; Ovulation ; Cytoplasmic granules ; Papilloma ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes of rabbit germinal epithelium at different times after an ovulatory dose of human chorionic gonadotrophin (HCG) were studied by scanning electron microscopy. Surface cells far from follicles did not show any consistent changes after HCG. However, germinal cells on growing follicles increased in size, while their microvilli successively decreased in length and number and eventually disappeared. At six hours after HCG, the cells over the apex showed protruding blebs and vesicles. Pour hours later the surface cells at the base had increased from about 7 to 12 μ in diameter and the contours of intracellular round structures were just visible. Half-way up to the apex the surface cells were still larger and contained several prominent intracellular round structures. At the apex the cells were collapsed and occasionally missing just before rupture. As regards the interpretation of these findings and their relation to the mechanism of ovulation, much remains to be done. However, since distinct and consistent changes characteristic of the later stages before rupture were found, the scanning electron microscope appears to be a valuable and convenient tool to evaluate the effect of different substances or procedures on the ovulatory process.
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    Cell & tissue research 150 (1974), S. 21-41 
    ISSN: 1432-0878
    Keywords: Cell surface ; Dinoflagellata ; Gonyaulax ; Theca ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The theca of Gonyaulax polyedra has been studied by light- and scanning electron microscopy. 1. The plates of “old” cells have growth rims in a regular pattern. 2. The growth rims overlap the margins of the adjacent plates. From this observation a rule of plate overlap can be deduced for the whole theca. 3. The degree of sculpture seems to correspond with the age of the plate. 4. For ecdysis, the armour opens along a line, that follows the borders of definite plates. 5. On the surface of the “naked” protoplast the borders of the abandoned plates are indicated by ridges, which are interpreted to be remnants of the sutures, i.e. joined membranes of neighbouring pellicular alveoles. 6. “Naked” cells divide by constriction. 7. During division of armoured cells, the theca ruptures. The line, along which the plates of the ancestral skeleton separate (fission line), is indicated by differences in the degree of sculpture of “old” and “new” plates.
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    Cell & tissue research 150 (1974), S. 125-141 
    ISSN: 1432-0878
    Keywords: Ductus cochlearis ; Lizard (Skink) ; Sensory hair cells ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The papilla basilaris of scincid lizards is relatively long, slightly curved or bowed, and characteristically has an apical terminal expansion. A limbus-attached tectorial membrane is present but is apparently not continuous with the tectorial material covering the hair cells of the papilla. The hair cells of the apical expansion are covered by a thick spongy mass of tectorial material, while the hair cells above (dorsal to) the apical region are covered by thickened tectorial material that is in the form of uniquely sculptured, twisted or folded drape-like masses (sallets). The surface of the basal (dorsal) quarter of the papilla is unusual in that it is concave rather than convex. The expanded terminals of the hair cell kinocilia are also unusual in being arrowhead-shaped. Kinocilial orientation of the non-apical papillary hair cells is simply bidirectional; the hair cells on each side of the papillary axial midline are oriented toward the midline. Kinocilial orientation of the hair cells of the apical expansion is more complex with the peripheral neural and abneural rows both being abneurally directed, and the central rows being at first neural in orientation, but becoming abneurally oriented as the apical tip is approached. At the apical tip region, most all hair cells are abneurally oriented.
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    Cell & tissue research 154 (1974), S. 511-518 
    ISSN: 1432-0878
    Keywords: Paraventricular organ ; Rana temporaria ; Scanning electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy of the ventricular surface of the paraventricular organ of Rana temporaria shows that it has the aspect of an uneven crest-like structure consisting of numerous tightly-packed bulbs which protrude into the cavity of the third ventricle. From the comparison with transmission electron micrographs it is concluded that these bulbs are the ventricular end-bulbs of the dendrites of the nerve cells of the paraventricular organ. At its apical part, the typical aspect of the ventricular surface of the paraventricular organ sharply contrasts with the surrounding ependymal surface which is covered with numerous cilia.
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    Rock mechanics and rock engineering 5 (1973), S. 237-248 
    ISSN: 1434-453X
    Keywords: Aggregate ; Compressibility ; Compressive strength ; Particle size ; Rockfill ; Rock Mechanics ; Void Ratio ; Strain ; Stress ; Average particle size ; Compressive strength ; Void ratio ; Initial void ratio ; Final void ratio ; Angularity number ; Uniformity coefficient ; Deformation ; Force ; Modulus of elasticity ; Poisson's ratio ; Aggregat ; Kompressibilität ; Druckfestigkeit ; Körnung ; Steinpackung ; Felsmechanik ; Relativer Porenraum ; Verformung ; Spannung ; Korndurchmesser ; Druckfestigkeit ; relativer Porenraum ; anfänglicher relativer Porenraum ; endrelativer Porenraum ; Eckigkeit ; Ungleichförmigkeitsgrad ; Verformung ; Kraft ; Elastizitätsmodul ; Poisson-Zahl ; Agrégat ; Compressibilité ; résistance à la compression ; taille des particules ; enrochement ; mécanique des roches ; indice des vides ; déformation ; contrainte ; diamètre des grains ; résistance à la compression ; indice des vides ; indice des vides initial ; indice des vides final ; angulairité ; coefficient d'uniformité ; déformation ; force ; module d'élasticité ; coefficient de Poisson
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Description / Table of Contents: Zusammenfassung Einige Faktoren, die die Kompressibilität von Aggregaten bestimmen Diese Arbeit untersucht die Variablen, die die Kompressibilität von Gesteinsaggregaten bestimmen, und liefert experimentelle Angaben über das Verhalten von Kalkstein-, Dolerit- und Sandsteinproben bis zu 19,0 mm Korngröße. Die Ergebnisse weisen darauf hin, daß, während der anfängliche relative Porenraum des Aggregats den Grad der potentiell vorhandenen Kompressionsspannung bestimmt, der durchschnittliche Aggregatsdurchmesser (d m) und die eigentliche Druckfestigkeit (S c) die Kompressibilitäts-Spannungs-Verformungscharakteristik laut der Formel $$\varepsilon \alpha \ln \frac{{\sigma d_m {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}}{{S_c }}$$ bestimmen.
    Abstract: Résumé Influence de la résistance des particules sur la compression d'un agrégat broyé Les auteurs examinent les paramètres qui affectent la compressibilité des agrégats de roches et présentent des résultats expérimentaux obtenus avec des échantillons de calcaire, de dolérite et de grès, sur l'influence du diamètre des grains en-dessous de 19 mm. Les résultats suggèrent que l'indice des vides initial impose le taux de la déformation à la compression dont on dispose, cependant que le diamètre des grains (d m) et la résistance à la compression (S c) définissen les caractéristiques de la courbe de compressibilité.
    Notes: Summary The Effect of Particle Strength on the Compression of Crushed Aggregate The paper examines the variables controlling the compression of rock aggregates, and presents experimental data on the behaviour of limestone, dolerite and sandstone samples in size ranges up to 19.0 mm. The results suggest that while the initial void ratio of the aggregate determines the degree of compressive strain potentially available, the average aggregate dimension (d m) and intrinsic compressive strength (S c) determine the compressive stressstrain characteristics in the form, $$\varepsilon \alpha \ln \frac{{\sigma d_m {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}}{{S_c }}$$
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  • 99
    ISSN: 1432-0878
    Keywords: Fourth ventricle ; Human ; Ependyma ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy was used to assess the ultrastructural differences exhibited by the varigated ependymal lining of the near-term human fetal 4th ventricle. The central portion of the fourth ventricular floor, including the median sulcus is punctuated by numerous clumps of cilia. The density of cilia here is not as great as that described for other regions of the human cerebral ventricular system; accordingly, underlying substructure can be noted. There are distinct differences between ependymas that line the floor of the fourth ventricle with those of the adjacent area postrema. The latter region possesses not cilia, but instead exhibits a dense knap of microvilli. The ultra-architecture of the choroid plexus is relatively similar to that of other circumventricular organs with the exception that it possesses small isolated groups of cilia as well as microvilli. These findings are discussed with respect to the dynamics of local CSF movement and flow, ependymoabsorption and ependymosecretion
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 138 (1973), S. 31-39 
    ISSN: 1432-0878
    Keywords: Olfaction ; Fishes ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The olfactory rosettes of Tarletonbeania crenularis are contained within paired membranous olfactory chambers opening to the exterior through a pair of nostrils. The margins of the anterior nostril form an infundibulum that may direct a current of water between the lamellae of the olfactory rosette and out of the posterior nostril as the fish swims through the water. The number of lamellae in a rosette is variable, and each consists of an olfactory epithelium containing receptor cells, supporting cells, basal cells, mucus cells and bipolar neurons. The olfactory surface for the most part is nonciliated and appears rugose in scanning electron micrographs. Receptor elements are located along the central axis of the rosette and on the surfaces of the distal margins of the lamellae.
    Type of Medium: Electronic Resource
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