On the structure of the teeth, the vascularity of those organs, and their relation to bone

1843 ◽  
Vol 4 ◽  
pp. 70-70
Keyword(s):  
Transparent Medium ◽  
Transparent Material ◽  
Central Cavity ◽  
Transparent Layer ◽  
Muriatic Acid ◽  
Inner Surface ◽  
Abundant Evidence ◽  
Dense Mass

The microscopical examinations which the author has made of the structure of the teeth of man and various animals, lead him to the conclusion that their bony portions are formed of minute tubes, dis­posed in a radiated arrangement, in lines proceeding everywhere perpendicularly from the inner surface of the cavity containing the pulp. These tubuli are surrounded by a transparent material, which cements them together into a solid and dense mass. He finds, by applying the test of muriatic acid, that carbonate as well as phos­phate of lime enters into their composition. In man, the tubuli, du­ring their divergence from their origin at the surface of the central cavity, send off a number of very minute fibrils ; and on approach­ing the enamel or the granular substance, which cover respectively the crown and the fangs of the tooth, the tubuli divide into smaller ones, which freely anastomose with one another, and then either are continued into the enamel, or terminate at the boundary between these two substances. Various modifications of this structure, ex­hibited in the teeth of different animals, in the class Mammalia and Fishes more particularly, are minutely described. The granular sub­stance appears to be composed of irregularly shaped osseous gra­ nules, imbedded in the same kind of transparent medium which ce­ments the tubuli together. External to the granular portion, the author finds another substance entering into the formation of the simple tooth, and commencing where the enamel terminates; and which he describes as beginning by a thin and transparent layer con­taining only a few dark fibres, which pass directly outwards; but assuming, as it proceeds towards the apex of the fang, greater thickness and opacity, and being traversed by vessels. External to the enamel, and in close connexion with it, in com­pound teeth, is situated the crusta petrosa, a substance very similar to the bony layer of the simple tooth. It contains numerous cor­puscles, and is traversed by numerous vessels entering it from with­out, and anastomosing freely with one another, but terminating in its substance. These investigations of the structure of the different component parts of teeth, furnish abundant evidence of their vascu­larity and consequent vitality.

The ultrastructure of the cysticercoid of Tatria octacantha Rees, 1973 (Cyclophyllidea: Amabiliidae) from the haemocoele of the damsel-fly nymphs Pyrrhosoma nymphula, Sulz and Enallagma cyathigerum, Charp

Parasitology ◽  
1973 ◽  
Vol 67 (1) ◽  
pp. 85-103 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Surface Area ◽  
Outer Surface ◽  
Dense Material ◽  
Central Cavity ◽  
Electron Dense Material ◽  
Inner Surface

The cysticercoid of Tatria octacantha Rees, 1973 from the haemocoele of damsel-fly nymphs consists of an outer and inner cyst. The tegument of the outer surface of the outer cyst bears long slender microvilli which increase the surface area presumably for absorption. The tegument on the inner surface bears electron-dense microvilli and contains vesicles embedded in an electron-dense material. The contents of the vesicles resemble those of the central cavity in which the inner cyst floats freely. Nutrients absorbed by the outer cyst pass into the central cavity where they are available to the inner cyst.

Observations on the growth and development of the epidermis

1851 ◽  
Vol 5 ◽  
pp. 563-564
Keyword(s):  
Growth And Development ◽  
Single Layer ◽  
Pigment Cells ◽  
Careful Examination ◽  
Transparent Layer ◽  
Inner Surface ◽  
Globular Form ◽  
Deep Stratum

The author adduces evidence derived from his microscopic observations, in confirmation of the commonly received doctrine respecting the origin of the cells of the epidermis and epithelium generally, from the materials furnished by the liquor sanguinis or plasma of the blood; which fluid, passing by endosmosis through the walls of the capillary vessels and peripheral boundary of the surface, developes granules by a vital process, analogous to coagulation. On a careful examination of the inner surface of the epidermis with the aid of the microscope, he finds it to be composed of four kinds of elements, arranged in such a manner as to constitute an irregular plane, similar to a tesselated or mosaic pavement. These elements are,—1. Granules , which the author terms primitive , of a globular form, solid and apparently homogeneous, and measuring about 1-20,000th part of an inch in diameter. 2. Aggregated granules , having about double the diameter of the former and apparently composed of as many of these as can be aggregated together without leaving an unoccupied space in the centre of the mass. 3. Nucleated granules measuring in diameter from the 6000th to the 4000th part of an inch, each being composed of an aggregated granule as a nucleus, enveloped by a single layer of aggregated granules, giving to the whole mass an oval or circular, and at the same time flattened shape. Their constituent granules have acquired, during this aggregation, greater density, and are separated from each other by distinct interstitial spaces filled with a transparent homogeneous substance. 4. Nucleolo-nucleolated cells pervading the deep stratum of the epidermis, and of which the longer diameter measures from the 3000th to the 2500th part of an inch. These cells, which constitute the principal portion, and may be regarded as the chief constituent of the epidermis, are formed from the nucleolated granules, on the exterior of which there is superposed a transparent layer, bounded by a well-defined outline, by the dark interstitial substance of the wall of the cell; the nucleolated granule being the nucleus, and the aggregated granule the nucleolus of these primitive cells of the epidermis. The author is of opinion that the nuclei, up to a certain point, grow with the cells, by the separation of the original granules from the deposition between them of interstitial matter, and also by the cleavage of the latter and the consequent multiplication of the granules. This peripheral growth of the cells is totally different from the mode of growth described by Schwann, and explains the disappearance of the nucleus in the scales of the epidermis. The observations of the author lead him to believe that the same process of development and of growth is followed in the epithelium as in the epidermis; and he offers evidence, showing that similar arrangements take place in the cells of melanosis, in the pigment cells of the choroid membrane of the eye, and in those of the skin of the negro.

A SEM and Light Microscope Study of the Epidermal Leaf Structures of the Carnivorous Plant, Sarracenia purpurea, L.

1971 ◽  
Vol 29 ◽  
pp. 358-359
Author(s):  
B. J. Panessa ◽  
J. F. Gennaro
Keyword(s):  
Methylene Blue ◽  
Toluidine Blue ◽  
Outer Surface ◽  
Microscope Study ◽  
Light Microscope ◽  
Carnivorous Plant ◽  
Sarracenia Purpurea ◽  
Inner Surface

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.

Gastric Ulcers Produced by Cisplatin

1981 ◽  
Vol 39 ◽  
pp. 582-583
Author(s):  
S.K. Aggarwal ◽  
J. San Antonio
Keyword(s):  
Electron Microscopy ◽  
Single Dose ◽  
Side Effects ◽  
Antitumor Agent ◽  
Gastric Ulcers ◽  
Enzyme Cytochemistry ◽  
Intestinal Toxicity ◽  
Ovarian Cancers ◽  
Inner Surface

Cisplatin (cis-dichlorodiammineplatinum(II)) a potent antitumor agent is now available for the treatment of testicular and ovarian cancers. It is however, not free from its serious side effects including nephrotoxicity, gastro intestinal toxicity, myelosuppression, and ototoxicity. Here we now report that the drug produces peculiar bloating of the stomach in rats and induces acute ulceration.Wistar-derived rats weighing 200-250 g were administered cisplatin(9 mg/kg) ip as a single dose in 0.15 M NaCl. After 3 days the animals were sacrificed by decapitation. The stomachs were removed, the contents analyzed for pepsin and acidity. The inner surface was examined with a dissecting microscope after a moderate stretching for ulcers. Affected areas were fixed and processed for routine electron microscopy and enzyme cytochemistry.The drug treated animals kept on food and water consistently showed bloating and lesions (Fig. 1) with a frequency of 6-70 ulcers in the rumen section of the stomachs.

Bonafide Substructure in the Core of Ferritin

1985 ◽  
Vol 43 ◽  
pp. 322-323
Author(s):  
William H. Massover
Keyword(s):  
Phase Contrast ◽  
Central Cavity ◽  
Amplitude Image ◽  
Ultrastructural Studies ◽  
The Core ◽  
Hydrated Ferric Oxide ◽  
Imaging Artifact ◽  
Contrast Image ◽  
Protein Shell ◽  
Regular Patterns

Each molecule of ferritin (d = 130Å) contains a core of iron surrounded by a 24-subunit protein shell. The amount of iron stored is variable and is present within the central cavity (d = 80Å) as a hydrated ferric oxide equivalent to the mineral, ferrihydrite. Many early ultrastructural studies of ferritin detected regular patterns of a multiparticulate substructure in the iron-rich core [e.g., 3,4], Each small particle was termed a “micelle“; a theory became widely accepted that a core consisted of up to six micelles positioned at the vertices of an octahedron. Other workers recognized that the apparent micelles were smaller or even disappeared if images were recorded closer to exact focus [e.g., 5]. In 1969, Haydon clearly established that the observed substructure was really an imaging artifact; each apparent micelle was only a dot in the underfocused phase contrast image of the supporting film superimposed on the amplitude image of the strongly scattering metal.

Pathways for penetration of iron and negative stain across the protein shell of ferritin: Ultrastructural perspectives

1992 ◽  
Vol 50 (2) ◽  
pp. 1012-1013
Author(s):  
William H. Massover
Keyword(s):  
Outer Shell ◽  
X Ray Diffraction ◽  
Central Cavity ◽  
X Ray ◽  
Subunit Dissociation ◽  
Negative Stain ◽  
Analogous Question ◽  
Protein Shell

Molecules of the metalloprotein, ferritin, have an outer shell comprised of a polymeric assembly of 24 polypeptide subunits (apoferritin). This protein shell encloses a hydrated space, the central cavity, within which up to several thousand iron atoms can be deposited as the biomineral, ferrihydrite. The actual pathway taken by iron moving across the protein shell is not known; an analogous question exists for the demonstrated entrance of negative stains into the central cavity. Intersubunit interstices at the 4-fold and 3-fold symmetry axes have been defined with x-ray diffraction, and were hypothesized to provide a pathway for penetration through the outer shell; however, since these channels are only 4Å in width, they are much too small to allow simple permeation of either hydrated iron or stain ions. A different hypothesis, based on studies of subunit dissociation from highly diluted ferritin, proposes that transient gaps in the protein shell are created by a rapid reversible subunit release and permit the direct passage of large ions into the central cavity.

High-resolution gold labeling

1993 ◽  
Vol 51 ◽  
pp. 330-331
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya ◽  
Kyra Carbone ◽  
Martha Simon ◽  
Beth Lin ◽  
...  
Keyword(s):  
Dihydrofolate Reductase ◽  
Polypeptide Chain ◽  
External Surface ◽  
Gold Cluster ◽  
Macromolecular Complex ◽  
Gold Compound ◽  
Central Cavity ◽  
Chain Folding ◽  
E Coli ◽  
Chaperonin Groel

A recently developed 1.4 nm gold cluster has been found to be useful in labeling macromolecular sites to 1-3 nm resolution. The gold compound is organically derivatized to contain a monofunctional arm for covalent linking to biomolecules. This may be used to mark a specific site on a structure, or to first label a component and then reassemble a multicomponent macromolecular complex. Two examples are given here: the chaperonin groEL and ribosomes.Chaperonins are essential oligomeric complexes that mediate nascent polypeptide chain folding to produce active proteins. The E. coli chaperonin, groEL, has two stacked rings with a central hole ∽6 nm in diameter. The protein dihydrofolate reductase (DHFR) is a small protein that has been used in chain folding experiments, and serves as a model substrate for groEL. By labeling the DHFR with gold, its position with respect to the groEL complex can be followed. In particular, it was sought to determine if DHFR refolds on the external surface of the groEL complex, or whether it interacts in the central cavity.

Probabilistic evaluation of detection capability of eddy current testing to inspect pitting on a stainless steel clad using multiple signal features

2020 ◽  
Vol 64 (1-4) ◽  
pp. 47-55
Author(s):  
Takuma Tomizawa ◽  
Haicheng Song ◽  
Noritaka Yusa
Keyword(s):  
Stainless Steel ◽  
Eddy Current ◽  
Pressure Vessels ◽  
Eddy Current Testing ◽  
Probability Of Detection ◽  
Current Testing ◽  
Multiple Signal ◽  
Signal Features ◽  
Inner Surface ◽  
Drill Holes

This study proposes a probability of detection (POD) model to quantitatively evaluate the capability of eddy current testing to detect flaws on the inner surface of pressure vessels cladded by stainless steel and in the presence of high noise level. Welded plate samples with drill holes were prepared to simulate corrosion that typically appears on the inner surface of large-scale pressure vessels. The signals generated by the drill holes and the noise caused by the weld were examined using eddy current testing. A hit/miss-based POD model with multiple flaw parameters and multiple signal features was proposed to analyze the measured signals. It is shown that the proposed model is able to more reasonably characterize the detectability of eddy current signals compared to conventional models that consider a single signal feature.

Intensification of Open Gutters Operation

2020 ◽  
pp. 66-70
Keyword(s):  
Water Flow ◽  
Vortex Formation ◽  
Hydraulic Testing ◽  
Polymer Materials ◽  
Bottom Surface ◽  
Artificial Roughness ◽  
Transport Capacity ◽  
Corrugated Surfaces ◽  
Inner Surface ◽  
Dispersed Inclusions

The intensification of the work of open gutter by applying textured shells to their bottom surface, forming an artificial roughness, is considered. It is shown that the presence of corrugated surfaces contributes to vortex formation during water flow and improves the separation and transportation of mineral impurities previously dropped into the bottom of the gutters. The implementation of operations to improve the structure of the gutters is possible during the repair and restoration works with the use of modern polymer materials. The design of a small-sized hydraulic stand, which makes it possible to study the transport capacity of flows containing solid inclusions, is presented. The method of research is hydraulic testing, accompanied by the use of chiaroscuro effect, as well as photo and film equipment. The optimal structure of the inner surface of the gutters and pipes providing vortex formation, which will improve the ability of the flow to carry out and transport foreign dispersed inclusions (sand) of different granulometric compositions, is determined.

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