scholarly journals Structure and microstructure of coronary dentin in non-erupted human deciduous incisor teeth

2002 ◽  
Vol 13 (3) ◽  
pp. 170-174 ◽  
Author(s):  
Luciane R.R S. Costa ◽  
Ii-Sei Watanabe ◽  
Márcia C. Kronka ◽  
Marcelo C.P. Silva

The dentin structure of non-erupted human deciduous mandibular and maxillary central and lateral incisor teeth was studied employing light and scanning electron microscopy. For light microscopy, nitric-acid-demineralized and ground sections were used. The sections were stained by hematoxylin-eosin, picrosirius and azo-carmim methods, and ground specimens were prepared using a carborundum disk mounted in a handpiece. For SEM study, teeth were frozen in liquid nitrogen and fractured at longitudinal and transversal directions. Structurally, demineralization and ground methods revealed tubules with primary and secondary curvatures, canaliculi, giant tubules, interglobular dentin, predentin, and intertubular dentin. Scanning electron microscopy showed three-dimensional aspects of dentinal tubules, canaliculi, peritubular dentin, intertubular dentin, and predentin. This study contributes to knowledge about dentin morphology showing characteristics of teeth not yet submitted to mastication stress.

2010 ◽  
Vol 177 ◽  
pp. 530-532 ◽  
Author(s):  
Xin Gang Yu ◽  
Shi Song Luo ◽  
Yan Na Gao ◽  
Hong Fei Wang ◽  
Yue Xiang Li ◽  
...  

The pore structure and microstructure of the foam concrete was analyzed by scanning electron microscopy and light microscopy combined with digital image analysis. The results show that: (1) even-distributed fine and close pores resulting in high strength and low permeability; (2) uneven-distributed large size pores and open pores lead to low strength and high permeability; (3) light microscopy combined with digital image analysis is a cheap and convenient tool fitting for the pore structure analysis of the foam concrete; (4) scanning electron microscopy is very appropriate for the pore structure and microstructure analysis of the foam concrete.


2016 ◽  
Vol 48 (3) ◽  
pp. 388 ◽  
Author(s):  
S. Karschová ◽  
J. Hajer

The spinning apparatus and silk of <em>Segestria senoculata</em> were studied with the use of scanning electron microscopy and light microscopy, which confirmed the presence of four categories of spigots connected with four types of spinning glands (<em>i.e</em>., <em>Glandulae ampullaceae major, Glandulae ampullaceae minor, Glandulae piriformes and Glandulae pseudaciniformes</em>). New data about the morphology of spinnerets and spigots were obtained for both the adults and nymphal stages of both sexes. For the first time the silken threads of retreats, signal threads and attachment discs of the members of <em>Segestria</em> were subjected to a detailed SEM study. The data resulting from studying the spinning apparatus of <em>S. senoculata</em> was compared to current knowledge of the silk producing systems of families belonging to the Dysderoidea superfamily. Silks that are emitted from spigots in the course of retreat construction are not (similarly to the other dysderoids) processed by the spider’s legs during the subsequent process of hardening. Apart from the major ampullate glands/spigots, segestriids also possess developed minor ampullate glands. Minor ampullate threads are used by <em>S. senoculata</em> spiders when making their signal threads.


Author(s):  
E. G. Kokko ◽  
D. A. Gaudet

Scanning electron microscopy (SEM) applied to paraffin-embedded tissue section is compared with the traditional techniques of light microscopy (LM) and surface SEM for the study of invasion by a plant-pathogenic fungus. SEM of paraffin-embedded sections of wheat leaves infected by Coprinus psychromorbidus consistently yielded high-quality micrographs showing three-dimensional views of both internal and external disease development processes. When the orientation of the specimen in the SEM is manipulated, the specimen can be viewed from different perspectives. The technique is simple and inexpensive and combines the advantages of great depth of focus and high resolution of the SEM with the simple preparatory techniques employed for light microscopy.


2014 ◽  
Vol 14 (3) ◽  
pp. 261-268
Author(s):  
Olivar C. Castejón ◽  
Aury Caraballo ◽  
Oliver Castejón ◽  
Elizabeth Cedeño

Objectives: the purpose of this study is to use light microscopy and scanning electron microscopy to determine the effect of edema on the structure of the molar vesicle. Methods: samples were taken from the complete hydatidiform mole and processed using conventional light and scanning electron microscopy techniques and an observation protocol that identified four variables: factors underlying the development of edema; the condition of the trophoblast basement membrane, development of the villi, accumulation and degeneration of sulphated mucosubstances at stromal level. Results: light microscopy showed a permeable trophoblastic basement membrane, a swollen syncytium, edematous regions disorganizating the stromal region and causing ischemic necrosis of cells. Using scanning electron microscopy, the basement membrane was found to be distended and thickened, with large irregular holes for the entry and movement of liquid, leaving a wide range of fluids during the influx process and depriving stromal cells of nutrition. Conclusions: a new three-dimensional view of the changes brought about by the entry of fluids into the stroma of molar hydropic vesicles was provided by scanning electron microscopy and confirmed by light microscopy, thereby explaining the changes occurring at the level of the stroma as an effect of the edema.


2012 ◽  
Vol 18 (5) ◽  
pp. 1106-1111 ◽  
Author(s):  
Lei Wang ◽  
Jin Shao ◽  
Tingjun Ye ◽  
Lianfu Deng ◽  
Shijing Qiu

AbstractScrew implantation inevitably causes microdamage in surrounding bone. However, little is known about the detailed characteristics of microdamage in peri-screw bone. In this study, we developed a method to construct microdamage cast with methylmethacrylate (MMA) and observed the cast using scanning electron microscopy (SEM). In basic fuchsin stained bone sections observed by bright-field and fluorescence microscopy, diffuse damage, cross-hatched damage, and linear cracks were all presented in peri-screw bone. Using MMA casting/SEM method, we found numerous densely packed microcracks in the areas with diffuse damage. The osteocyte canaliculi and the microcracks consisting of diffuse damage had a similar diameter (or width), usually <0.5 μm, but their morphology was largely different. In the area with cross-hatched damage, the orientation of microcracks was similar to that in diffuse damage, but the number was significantly decreased. Many microcracks were thicker than 1 μm and associated with a rough surface. Large linear cracks (∼10 μm in diameter) occurred in different areas. Plenty of microcracks were present on the surface of some linear cracks. In conclusion, the MMA casting/SEM method can demonstrate the three-dimensional morphology of different types of microdamage, particularly the microcracks in diffuse damage, which are unable to be shown by light microscopy.


2017 ◽  
pp. 17
Author(s):  
Aida Carrillo-Ocampo ◽  
E. Mark Engleman

The seed of huauzontle (Chenopodium berlandieri ssp. nuttalliae) was studied by light microscopy and scanning electron microscopy. When the outer integument arises around the young ovule, instead of covering the inner integument and the nucellus, it grows backwards and partially surrounds the funiculus . When the pericarp is removed from the mature fruit, the seed is straw colored, because only the tegmen covers the seed. The chalaza of this seed has the form of a truncate cone, with the elliptical base towards the nucellus. In this zone of contact between the chalaza and the nucellus. a cuticle is deposited that surrounds some cells and makes a three dimensional network. This chalazal network is in contact with a smooth nucellar cuticle that fom1s part of the seed coat. The inversion of the inner integument could represent a selected mutation during the process of domestication.


Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).


Author(s):  
D. Johnson ◽  
P. Moriearty

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.


Sign in / Sign up

Export Citation Format

Share Document