Replica-based inspection of enamel wear microfeatures

2020 ◽  
Vol 31 (5) ◽  
pp. 279-290
Author(s):  
Manhal Ijbara ◽  
Kanae Wada ◽  
Junichiro Wada ◽  
Jayanetti Asiri Jayawardena ◽  
Michiyo Miyashin
Keyword(s):  
Electron Microscope ◽  
Nondestructive Evaluation ◽  
Protective Layer ◽  
Surface Wear ◽  
Human Teeth ◽  
Wear Process ◽  
Human Enamel ◽  
Surface Irregularities ◽  
Enamel Wear

BACKGROUND: Surface replication is a nondestructive evaluation technique applied in examining surface wear by recording surface irregularities, especially in conditions when surfaces of interest cannot be further manipulated to fit directly under a microscope to be examined. Enamel is the outermost protective layer of the human teeth and is constantly stressed by mastication forces which results in enamel wear. OBJECTIVE: To date, a procedure combining the clinical and microscopic examination of enamel surfaces is absent, which hinders the early diagnosis and comprehension of the wear process. METHODS: This study investigated the role of replication sheets in registering microscopic wear on human enamel surfaces by both negative and positive replication techniques. RESULTS: The sheets replicated wear features successfully. Sheets were compatible to use with multiple microscopes, with proper preparation, including high resolution microscopes such as the scanning electron microscope and transmitting electron microscope.

Human Enamel Replication

1976 ◽  
Vol 34 ◽  
pp. 180-181
Author(s):  
Norman L. Dockum ◽  
John G. Dockum
Keyword(s):  
Organic Matrix ◽  
Human Teeth ◽  
Human Enamel ◽  
Straight Line ◽  
Ultrastructural Characteristics

Ultrastructural characteristics of fractured human enamel and acid-etched enamel were compared using acetate replicas shadowed with platinum and palladium. Shadowed replications of acid-etched surfaces were also obtained by the same method.Enamel from human teeth has a rod structure within which there are crystals of hydroxyapatite contained within a structureless organic matrix composed of keratin. The rods which run at right angles from the dentino-enamel junction are considered to run in a straight line perpendicular to the perimeter of the enamel, however, in many areas these enamel rods overlap, interlacing and intertwining with one another.

scholarly journals Assessing the predictability of existing water-to-enamel geolocation models against known human teeth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Momoko Ueda ◽  
Lynne S. Bell
Keyword(s):  
Drinking Water ◽  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Dental Enamel ◽  
Threshold Value ◽  
Human Teeth ◽  
Country Level ◽  
Water Oxygen ◽  
Human Enamel

AbstractStable isotope analysis of human tissues has become a valuable tool for mapping human geolocation. This study adds to the existing knowledge of the relationship between oxygen stable isotopes in human enamel and drinking water by presenting enamel oxygen values in clinic-extracted human dental enamel with known provenance. The results from this study indicate that the theoretical isotopic relationship between enamel and drinking water oxygen is weak at the city and country-level. Differences of up to 15‰ were observed between predicted drinking water oxygen values using existing models and observed values, highlighting the complexity of using water/enamel conversion equations. The lower isotopic boundary of enamel oxygen values is now understood for Metro Vancouver at δ18Oc(VPDB) = – 11.0‰ and presents the possibility of using stable isotope analysis as an exclusionary tool where individuals falling below threshold value can be identified as non-local. Overall, this study’s results support the development of geographical reference maps for human enamel oxygen.

scholarly journals THE ORGANIZATION AND INNERVATION OF THE LUMINESCENT ORGAN IN A FIREFLY, PHOTURIS PENNSYLVANICA (COLEOPTERA)

1963 ◽  
Vol 16 (2) ◽  
pp. 323-359 ◽  
Author(s):  
David S. Smith
Keyword(s):  
Electron Microscope ◽  
Synaptic Vesicles ◽  
Light Emission ◽  
Nerve Endings ◽  
Tracheal Epithelium ◽  
Nerve Terminals ◽  
Tracheal System ◽  
Physiological Evidence ◽  
Effector System

The organization of the luminescent organ of an adult firefly has been studied with the electron microscope, and particular attention has been given to the disposition of nerve terminals within the organ. The cytological structure of the cells of the tracheal system, the peripheral and terminal axons, the photocytes and the cells of the dorsal ("reflecting") layer is described. Previous observations on the peripheral course of nerve branches alongside the tracheal trunks at the level of the dorsal layer and photocyte epithelium have been confirmed, and specialised nerve endings containing axoplasmic components structurally identical with "synaptic vesicles" and "neurosecretory droplets" have been identified, not in association with the surface of the photocytes, but lying between the apposed surfaces of two components of the tracheal epithelium: the tracheal end-cell and the tracheolar cell. These cytological findings are discussed in terms of available biochemical and physiological evidence concerning the mechanism of light emission in the firefly, especially with respect to the possible role of chemical "transmitter" action in triggering a response in a luminescent effector system.

scholarly journals Mitomycin C Inhibits Esophageal Fibrosis by Regulating Cell Apoptosis and Autophagy via lncRNA-ATB and miR-200b

2021 ◽  
Vol 8 ◽  
Author(s):  
Yin Zhang ◽  
Qinge Wang ◽  
Yuping Xu ◽  
Jing Sun ◽  
Yanbo Ding ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Mitomycin C ◽  
Cell Apoptosis ◽  
Optimal Dose ◽  
The Other ◽  
Fibroblast Cells ◽  
Transmission Electron ◽  
Esophageal Strictures ◽  
Related Proteins

Benign esophageal strictures (BESs) frequently results from esophageal fibrosis. The transformation of fibroblasts into fibrocyte is an important cause of fibrosis. The treatment of fibrosis is challenging. Some previous studies have indicated the antifibrotic effect of mitomycin C (MMC). However, the mechanism of action of MMC and its optimal dose for treatment remains unclear. In the present study, the role of MMC in fighting fibrosis and its mechanism was investigated. Human esophageal fibroblast cells (HEFs)were treated without or with MMC, at 2, 5, 10 μg/ml, combining with mimic lncRNA-ATB, miR-200b inhibitor, rapamycin (RAPA), and 3-Methyladenine (3-MA). The cell viability, and cell apoptosis were evaluated. In addition, expression of apoptosis related proteins (caspase8 and caspase3), autophagy related proteins (LC3II and ATG5) and fibrosis related proteins (α-SMA collagen-1 and TGF-β) were also evaluated. Furthermore, autophagosome was observed by transmission electron microscope. Results showed that the expression of lncRNA-ATB was down-regulated and miR-200b was up-regulated after treated with MMC. And MMC induced cell apoptosis and inhibited cell autophagy. On the other hand, RAPA, mimic lncRNA-ATB and miR-200b inhibitor reduced fibrogenic effect of MMC on HEFs. Collectively, this study suggests that MMC inhibited esophageal fibrosis by regulating cell apoptosis and autophagy via downregulating lncRNA-ATB and upregulating miR-200b.

The Mesogloea of Pelagia noctiluca

1959 ◽  
Vol s3-100 (52) ◽  
pp. 599-610
Author(s):  
G. CHAPMAN
Keyword(s):  
Electron Microscope ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Pelagia Noctiluca ◽  
Fresh State

The arrangement of the mesogloea fibres of Pelagia noctiluca is described chiefly from material examined in the fresh state. The role of the mesogloea in swimming is shown to be the antagonization of the subumbrellar circumferential muscles. The fibres of the mesogloea are shown to be collagenous by their contraction on heating, their amino-acid composition, and their appearance under the electron microscope. A suggestion is made to account for the characteristic arrangement of the fibres at a distance from the cellular layers.

Cytological and cytochemical studies of centrifuged eggs of the slug Avion ater rufus L.

Development ◽  
1972 ◽  
Vol 27 (1) ◽  
pp. 1-13
Author(s):  
A. H. Sathananthan
Keyword(s):  
Electron Microscope ◽  
Cell Membrane ◽  
Sea Urchin ◽  
Cell Organelles ◽  
Chemical Substances ◽  
Important Chemical ◽  
Equatorial Band ◽  
Hyaline Zone ◽  
Egg Cortex

The stratification of various cell organelles and of important chemical substances have been studied in the eggs of the slug, after moderate centrifugation. As in other molluscs the egg contents stratify typically into three well-defined zones - lipid, L hyaline and yolky zones - but a distinct equatorial band of inclusions consisting mainly of F phagosomes and associated lysosomes was detected in the most centrifugal region of the hyaline zone. The sub-stratification of various cell inclusions in their respective zones was determined in some detail. The role of the cell membrane and egg cortex in the redistribution of these inclusions and the nature of the ergastoplasm are discussed in the light of electron-microscope studies of eggs of this slug and of the sea urchin.

In vitro investigation of human enamel wear by dental porcelain

2019 ◽  
Vol 30 (4) ◽  
pp. 365-374
Author(s):  
Yoshiharu Nakamura ◽  
Takatsugu Yamamoto ◽  
Yuko Shigeta ◽  
Takumi Ogawa
Keyword(s):  
Dental Porcelain ◽  
Human Enamel ◽  
In Vitro Investigation ◽  
Enamel Wear

Preparation and Characterization of Ni/ZrCoCe Stack Getter Films

2019 ◽  
Vol 944 ◽  
pp. 619-624
Author(s):  
Peng Yuan ◽  
Yao Zong Sui ◽  
Xiao Zhang ◽  
Hao Liu ◽  
Feng Wei ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Magnetron Sputtering ◽  
Film Surface ◽  
Protective Layer ◽  
Sem Analysis ◽  
And Diffusion ◽  
Highly Porous ◽  
Scanning Electron

In order to improve the oxidation resistance of the ZrCoCe getter, highly porous Ni/ZrCoCe stack getter films were grown by the magnetron sputtering method. Scanning electron microscope (SEM) analysis indicate that the Ni/ZrCoCe stack film is composed of isolated columns. The film surface with cauliflower-like topography is formed among finely packed nanocrystals. Gas sorption investigation shows that the Ni/ZrCoCe stack film can be activated at 300 °C for 30 min and exhibits more favorable sorption capability than ZrCoCe bi-layered film. XPS results show that the Ni protective layer can play an important role in protecting the ZrCoCe film against oxidation. It can also improve the surface dissociation and diffusion of H2.

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