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White enamel patches on approximal surfaces of human teeth were examined with a scanning electron microscope following the removal of plaque. The affected areas disclosed a honeycomb-like structure constructed of enamel prisms, the cores of which were preferentially dissolved. The defects resembled those due to acid decalcification. [ABSTRACT FROM AUTHOR]

Surface textures of quartz sand grains from several glacial environments at the Feegletscher, Switzerland examined by means of scanning electron microscopy are described. The difference between supraglacial and subglacial material is very slight. At the moment the interpretation of these textures must be done with care until the full statistical relation to environments can be ascertained. This does not necessarily invalidate earlier investigations although it does mean that glacial and extraglacial environments in the vicinity of glaciers are apparently not distinguishable. Examination of surface precipitation features suggests a sequence of events which can be used to help discriminate between different ages of deposits in an area. A similarity between some of the surface debris from moraine samples and those seen in loess and quickelay deposits is also suggested. [ABSTRACT FROM AUTHOR]

This article informs that thirteen fossil Erica-type seeds extracted by D.G. Wilson from samples collected from the Cromer Forest Bed Series at Pakefield, Suffolk, and Beeston, Norfolk, were examined in the Cambridge Stereoscan Mark II scanning electron microscope at the New University of Ulster. Of the thirteen fossil seeds examined under S.E.M. five were assigned with varying degree of certainty to Erica lusitanica. They could be distinguished from Bruckenthalia spiculifolia on the basis of the characteristics already noted. One seed was tentatively identified with Erica tetralix L., though poor preservation made confirmation impossible. All but one of the remainder were too poorly preserved to permit confident identification.

The three-dimensional capture organs of the nematode-trapping fungus Arthrobotrys oligospora are presented in scanning electron micrographs. The fungus was grown directly on agar substrates or on millipore filters or glass cover slips placed on agar substrates. To avoid shrinkage of the soft-walled mycelial material, a fixation in OsO4-vapour was performed, before freeze-drying and coating with Au-Pd alloy. When capture organs were prepared in this way, it was possible to visualize them in their erect position in the scanning electron microscope. Young capture organs, both spontaneously formed and nematode-induced, remained standing better than old ones. An adhesive substance on the capture organs, with the aid of which nematodes are trapped, seems to be visible in these pictures. [ABSTRACT FROM AUTHOR]

The pressure side of human premolars subjected to experimental movement for 5-76 d were studied in the scanning electron microscope. Sham-operated and untreated premolars were used as controls. In order to study the morphology and occurrence of root resorptions, the organic tissue was removed using 1:2 diamino ethane or sodium hypochlorite and the denuded root surfaces were re-examined in the scanning electron microscope. Areas of compressed soft tissue were regularly present and the size, shape and number of such zones varied in the experimental groups. Initially, tissue affected by pressure was mainly located in the marginal region and subsequently the mid-portion of the roots became generally influenced. Removal of hyalinized tissue started shortly after the formation, and during this soft tissue removal the underlying hard tissue was resorbed. Observation of circumferentially removed, coalesced fibers corresponded with the finding of extensively resorbed lacunae in the mineralized tissue beneath. The resorptive processes of the cementum began after 10 d as round cavities measuring about 6 μm. Further resorption in cementum was characterized by numerous small, thin-walled round lacunae which confluenced into extensive, shallow resorptions after 20 d. Dentin was distinguished by the presence of tubules, and in sites of active resorption removal of mineral crystals had occurred, exhibiting a latticed fiber arrangement. [ABSTRACT FROM AUTHOR]

Sound, demineralized adult guinea pig dentin was observed by means of the scanning electron microscope. The dentinal tubules were fairly regular, some of them containing odontoblastic processes (Tomes fibers). These fibers were smooth surfaced, branching and much smaller than the surrounding tubules. Their small diameters were probably caused by the preparation procedures. The inner tubular walls were rough, probably because of interlacing collagen fibrils. The peritubular dentin was relatively compact and composed of a considerable amount of cross-striated fibrils. Similar fibrils were found in the intertubular zones where they were arranged in fiber-bundles giving the intertubular zones a honeycombed or sponge like appearance. Such a distinct honeycombed appearance was not found in transmission electron microscope studies of dentin. This discrepancy is possibly due to differences in tissue preparation. The relatively poor development of peritubular dentin compared with intertubular dentin is in agreement with other studies in animals with continued tooth growth. [ABSTRACT FROM AUTHOR]

One type of eccrine anidrosis, that caused by occlusion of the sweat pore at or near the skin surface, was studied using the scanning electron microscope. In contrast to the normal, patent eccrine ostium, seemingly amorphous, non-cellular, intraluminal material plugs the superficial pore in formalin-produced anidrosis. Interference with sweat delivery in psoriasis, also due to high-level blockage of the duct, appears to result from obstruction by abnormal cellular scale associated with the disease process. Unlike earlier investigative work, which relied primarily on indirect evidence, the scanning electron microscope allows more detailed observation of the detect which causes the sweat disorder. [ABSTRACT FROM AUTHOR]

We have used the scanning electron microscope to investigate the changes that occur in scalp hair during infection with Trichophyton violaceum. We provide information on the morphology of these dermatophytes and present evidence that their hyphae dig tunnel-like burrows into the hair shaft, dissociating hair into keratin fibrils. [ABSTRACT FROM AUTHOR]

Examines quartz sand grains from a tropical environment using a scanning electron microscope. Features found to be in occurrence in the quartz sand grains including solution pits, solution crevasses, and chemical etching along quartz structures.

Unpollinated, cross-pollinated and self-pollinated stigmas of Brussels sprouts and kale were examined in a scanning electron microscope as fresh uncoated specimens. The stigmatic papillae are closely appressed in young stigmas, but are held apart in the mature stigma by the swollen bases of the papilla cells. Some self-pollen tubes show obvious signs of inhibition by being very short, or by coiling over the surface of the papilla without penetrating it. Other self-pollen tubes appear to behave like cross-pollen tubes by producing tubes which penetrate papillae directly. The implications of these observations for the identification of the site of the incompatibility reaction are discussed. [ABSTRACT FROM AUTHOR]

The morphology of the inner and outer surfaces of cuticular membranes of mono- and dicotyledonous leaves and fruits was studied with the scanning electron microscope. Variations in surface structure are related to differences in thickness and composition of the membranes. Delicate leaf membranes have fine ridges and simple stomata, well-developed membranes, thick V-shaped ridges and heavily cutinized stomata. Fruit membranes show deep ridges and extensive secondary cutinization. The most heavily cutinized structures occur in membranes which yield high proportions of 10, 16-dihydroxyhexadecanoic or 9,10,18-trihydroxyoctadecanoic acid which suggests that the membrane thickness and the complexity of the structural features are associated with the degree of hydroxylation of the constituent cutin acids. The relationship between the structure and composition of the cuticular membrane and the type and growth habit of the plant is discussed. [ABSTRACT FROM AUTHOR]

The electroscan microscope was used to show details of the external structure of the egg of cabbage root fly. The median area between the hatching lines differs from the more solid structure of the longitudinal ridges on the rest of the surface. On the pointed posterior end are small holes in the outer layer, but in contrast to wheat bulb fly, Leptohylemyia coarctata (Fall.), there are no distinct plastron areas around the micropyle at the blunt anterior end. The egg of cabbage root fly also lacks small plastron areas among the longitudinal ridges. [ABSTRACT FROM AUTHOR]

The dinophysoid dinoflagellates (to which Ornithocercus belongs) achieve growth both by increase in size of individual wall elements and, during rapid lateral expansion associated with cell division, by the formation of a semimeridional band of material termed the megacytic zone (MZ). The MZ maintains mother cell wall integrity during complete cytokinesis of the cell body and enclosure with new wall elements. The lists, extensive wing-like extensions of the wall, can only be reformed after dissolution of the MZ. Beginning near the ventral region (which is the last region of the wall to be duplicated), the MZ dislocates and its material is apparently resorbed. The last region of attachment is invariably dorsal and in several, but not all species, the daughter cells may remain attached during early list formation by a special remnant of the MZ, termed here the dorsal megacytic bridge (DMB). After full separation of daughter cells remnants of the DMB persist for an unknown but presumably short period. The topography of this process, involving radical ontogenetic alterations in the appearance of the daughter cells and some wall surfaces, is illustrated here by the scanning electron microscope. In addition 2 aberrant types of division are shown, one of which results in a double individual, termed a geminoid. [ABSTRACT FROM AUTHOR]

Stephanodiscus invisitatus Hohn and Hellerman, studied by means of light, transmission, and scanning electron microscopy, shows a range of frustule diameters from 6.4 to 13.3 μ. Variation in valve ornamentation can be correlated with specimen diameter. The striae number ranges from 16 to 20 in 10 μ. Various processes difficult to observe by light microscopy alone are described which arise from the inside and outside of the frustules.[SUP2] [ABSTRACT FROM AUTHOR]

Following positive identification by the usual cytogenetic means of a newborn girl with a triploid chromosome complement (69.XXX), a sample of hair was analyzed with the scanning electron microscope. The results of the observation on triploid human hair were compared to data gathered from the hair of normal newborn boys and girls. Significant differences were found between triploid and diploid hairs in mean width, mean width between the free edges of the cuticular scales, and average number of cuticular scales. [ABSTRACT FROM AUTHOR]