scholarly journals Comparative analysis of shrew tooth pigmentation using energy-dispersive X-ray spectroscopy (EDX)

2019 ◽  
Vol 323 (3) ◽  
pp. 347-363
Author(s):  
L.L. Voyta ◽  
V.S. Zazhigin ◽  
A.A. Miroljubov

The pigment of tooth enamel is an important odontological character for character for assessing Soricidae taxonomy and phylogeny. This paper describes the original observations of ‘pigment patterns’ (PPt) and ‘visible pigment’ (VPg) in fossil beremendiin shrews in light of the “differential pigmentation” found using UV detection and EDX analysis. The term “differential pigmentation” was used to describe the irregular pigmentation on the teeth of extinct Nesiotites (Neomyini). Our analysis of fossil and recent specimens reveals different reasons for differential pigmentation formation. The first reason is related to fossilization, namely, the chemical alterations of the buried specimen. The second reason is related to a developmental disorder, namely, the enamel organ disorder, which locally stops forming the twin enamel layer. Our original results and published data from EDX analysis of the enamel elemental content and SEM-image analysis of the enamel microstructure again raise the question of a relationship between ferruginous pigmentation and enamel microstructure. Further studies of the enamel structure and pigment chemical composition of red-toothed shrews compared to white-toothed shrews are required.

1980 ◽  
Vol 58 (6) ◽  
pp. 699-711 ◽  
Author(s):  
Ernest Spitzer ◽  
John N. A. Lott

Protein bodies of dry seeds of tomato (Lycopersicon esculentum) from radicle, hypocotyl, cotyledon, and endosperm tissue were extensively studied using thin-sectioning, freeze-fracturing and energy dispersive x-ray (EDX) analysis. Protein bodies varied in size, were oval to circular in section, and generally consisted of a proteinaceous matrix, globoid crystal, and protein crystalloid components. Size, shape, and arrangements of globoid crystals and protein crystalloids varied even within the same cell. Globoid crystals were generally oval to circular in section. They were always surrounded by a proteinaceous matrix. In a given protein body the number present ranged from a few to numerous. A protein body generally contained only one protein crystalloid. In section, protein crystalloids were irregular or angular in shape. They were composed of substructural particles which formed lattice planes. EDX analysis of tomato seed globoid crystals revealed the presence of P, K, and Mg in all cases, a fact that is consistent with globoid crystals being phytin-rich. Rarely, small amounts of calcium were found along with P, K, and Mg in globoid crystals of each of the tissue regions considered. The distribution pattern of cells with Ca containing globoid crystals was random. Small amounts of Fe and Mn were also found in the globoid crystals of protein bodies from certain cell types. These two elements, unlike calcium, were specific in terms of their distribution. Globoid crystals from the protodermal cells often contained Mn and Fe. The globoid crystals from provascular tissue of radicle, hypocotyl, and cotyledon regions often contained Fe while globoid crystals in the first layer of large cells surrounding these provascular areas always contained Fe. Results from EDX analysis of the proteinaceous material from the protein bodies are presented and discussed as are variations in elemental content due to different fixations.


2003 ◽  
Vol 82 (12) ◽  
pp. 982-986 ◽  
Author(s):  
T. Nagano ◽  
S. Oida ◽  
H. Ando ◽  
K. Gomi ◽  
T. Arai ◽  
...  

Amelogenin, enamelin, sheathlin (ameloblastin/ amelin), enamelysin (MMP-20), and KLK4 (EMSP-1) are the major structural proteins and proteinases in developing tooth enamel. Recently, odontoblasts were reported to express amelogenin, the most abundant enamel protein. In this study, we hypothesized that odontoblasts express all enamel proteins and proteases, and we measured their relative mRNA levels in enamel organ epithelia and odontoblasts associated with porcine secretory- and maturation-stage enamel by RT-PCR, using a LightCycler instrument. The results showed that amelogenin mRNA in secretory-stage EOE is 320-fold higher than in odontoblasts beneath secretory-stage enamel, and over 20,000-fold higher than in odontoblasts under maturation-stage enamel. Similar results were obtained for enamelin and sheathlin. Enamelysin mRNA levels were equivalent in these two tissues, while KLK4 mRNA was higher in odontoblasts than in secretory-stage EOE. These results support the conclusion that odontoblasts are involved in the formation of the enamel layer adjacent to enamel-dentin junction.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1543
Author(s):  
Francisca Guadalupe Cabrera-Covarrubias ◽  
José Manuel Gómez-Soberón ◽  
Carlos Antonio Rosas-Casarez ◽  
Jorge Luis Almaral-Sánchez ◽  
Jesús Manuel Bernal-Camacho

The porosity of mortars with recycled ceramic aggregates (10, 20, 30, 50, and 100% as a replacement of natural aggregate) was evaluated and analyzed using three different techniques. The results of gas adsorption (N2), Scanning Electron Microscopy (SEM) image analysis and open porosity allowed establishing the relationship between the recycled aggregate content and the porosity of these mortars, as well as the relationship between porosity and the physical and mechanical properties of the mortars: absorption, density, compressive strength, modulus of elasticity, and drying shrinkage. Using the R2 coefficient and the equation typology as criteria, additional data such as Brunauer, Emmett, and Teller (BET) surface area (N2 adsorption) established significant correlations with the mentioned properties; with SEM image analysis, no explanatory relationships could be established; and with open porosity, revealing relationships were established (R2 > 0.9). With the three techniques, it was confirmed that the increase in porosity is related to the increase in the amount of ceramic aggregate; in particular with gas adsorption (N2) and open porosity. It was concluded that the open porosity technique can explain the behavior of these recycled mortars with more reliable data, in a simple and direct way, linked to its establishment with a more representative sample of the mortar matrix.


Scanning ◽  
1986 ◽  
Vol 8 (5) ◽  
pp. 221-231 ◽  
Author(s):  
R. M. Edwards ◽  
J. Lebiedzik ◽  
G. Stone

2007 ◽  
Vol 534-536 ◽  
pp. 1529-1532 ◽  
Author(s):  
Celine Pascal ◽  
Jean Marc Chaix ◽  
A. Dutt ◽  
Sabine Lay ◽  
Colette H. Allibert

A steel/cemented carbide couple is selected to generate a tough/hard two layers material. The sintering temperature and composition are chosen according to phase equilibria data. The choice of optimal sintering conditions needs experimental studies. First results evidence liquid migration from the hard layer to the tough one, leading to porosity in the hard region. The study of microstructure evolution during sintering of the tough material (TEM, SEM, image analysis) evidences the coupled mechanisms of pore reduction and WC dissolution, and leads to temperature and time ranges suitable to limit liquid migration. The sintering of the two layer material is then shown to need further compromises to avoid interface crack formation due to differential densification.


2017 ◽  
Vol 11 (1) ◽  
pp. 527-538 ◽  
Author(s):  
Consuelo Sanavia ◽  
Marco Tatullo ◽  
Jessica Bassignani ◽  
Silvia Cotellessa ◽  
Giulia Fantozzi ◽  
...  

Background/Objective:The clinical conditions that lead to an alteration of the enamel structure are numerous. The diet high in sugars and acidifying substances, psychological stress that triggers parafunctional behaviors, the reduced intake of fiber-rich foods or alkalizing substances, together with other factors, contribute to demineralization of the tooth enamel. Dental mineralizing products on the current market are distinguished according to the dosage form, the active ingredient, the release technology, clinical indications and patient choice. Currently, it is necessary to propose to oral health professionals a guide to orient themselves in this chaotic choice, in order to prefer the most effective product for their own clinical target.Methods:Italian Society of Oral Hygiene Sciences-S.I.S.I.O. is one of the leading scientific Italian societies representing those dental hygienists working with high-quality standards and in agreement with scientific evidence: in the last year, the SISIO working group has carried out a study focused on remineralizing agents in dentistry, in order to give an authoritative point of view to indicate a guideline in the decision process of the choice of a remineralizing agent. We will report the results pointed out from the last consensus meeting in 2017.Results:We have reported the good the bad and the ugly have been discussed in a critical discussion of such topic.Conclusion:The SISIO experience has been reported in this position paper with the aim to serve as a useful aid in the daily choice of the clinical steps to perform, when dental professionals need to treat demineralized teeth.


2019 ◽  
Vol 14 (0) ◽  
pp. 3402049-3402049
Author(s):  
Hirohiko TANAKA ◽  
Shin KAJITA ◽  
Noriyasu OHNO

2010 ◽  
Vol 56 (195) ◽  
pp. 12-19 ◽  
Author(s):  
N.E. Spaulding ◽  
D.A. Meese ◽  
I. Baker ◽  
P.A. Mayewski ◽  
G.S. Hamilton

AbstractFirn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Gow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the grain area) in earlier methods. The new technique offers the advantages of greater accuracy and the ability to determine individual components of the microstructure (grain and pore), which have important applications in ice-core analyses. The new method is validated by calculating activation energies of grain boundary diffusion using predicted values based on the ratio of grain-size measurements between the new and existing techniques. The resulting activation energy falls within the range of values previously reported for firn/ice.


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