sem observation
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Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7280
Author(s):  
Mayumi Maesako ◽  
Takafumi Kishimoto ◽  
Shigetaka Tomoda ◽  
Taku Horie ◽  
Mitsuyoshi Yamada ◽  
...  

Resin composites employing structural coloration have recently been developed. These resins match to various tooth shades despite being a single paste. To accomplish this, the filler and base resin are tightly bonded, which is thought to provide excellent discoloration resistance. Here, we investigated the surface properties of one of these resins, including the discoloration of the repolished surface. We developed an innovative in vitro method to adjust the repolished surface, in which structural degradation is removed according to scanning electron microscopy (SEM) observation rather than by the naked eye. The resin samples (20 mm (length) × 10 mm (width) × 4 mm (depth)) were manufactured using this resin material. After accelerated aging of the resin by alkaline degradation, the resin was repolished and the discoloration (ΔE*ab), surface roughness (the arithmetic mean roughness (Ra)), and glossiness (the 60° specular) were measured. SEM observation showed that the appearance of the bond between the organic composite filler and base resin on the repolished surface was different from that on the mirror-polished surface. This revealed that according to our in vitro method it was difficult to make the repolished surface structurally identical to the mirror-polished surface. Among the properties of the repolished surface, the degree of discoloration did not change despite the rougher and less glossy surface. It can be concluded that the factors that induce discoloration in this resin composite are independent of the surface roughness and glossiness.


2021 ◽  
Author(s):  
Binbin Yang ◽  
Juan Li ◽  
Benjiang Zhou

Abstract For a long time, there is no clear-cut to identify some species of paragonimus in Yunnan Province, China. This paper involved the distribution of Paragonimus in Jinping country and Baoshan city, Yunnan province. In this experiment, the metacercariae, excysted metacercariae, eggs, adult worms were obtained from different hosts were observed and measured. Cats have been described as the appropriate definitive host of paragonimus sp., which are closed to P. cheni according to morphology. Especially the ovaries of adult worms are few and has no third branches. With SEM observation, their spines in the surface are single, a sharp-pointed knife or half-moon in shape and the end of a few of spines are bifurcate. While the clustered sequences strains of this study in the ITS2 tree clustered of Yunan is out sider of P. skirjabini complex and have the genetically greater distances than other isolates of the P. skrjabini complex. Therefore, the Paragonimus sp. of this study from Jinping County and Baoshan city are the same subspecies of P. skrjabini complex.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
S So ◽  
Y Takaku ◽  
I Ohta ◽  
F Tawara ◽  
T Hariyama

Abstract Study question Can the NanoSuit method to observe sperm cells in wet conditions help treat male infertility using a field emission scanning electron microscope (FE-SEM)? Summary answer Compared with the conventional fixation method, the NanoSuit method can easily prepare FE-SEM samples without causing contraction and denaturation of human sperm cells. What is known already Evaluation of sperm morphology by optical microscopy is important for identifying male infertility. FE-SEM observation is useful for a more detailed evaluation of sperm morphology; however, a lot of the morphological information of the cells is lost by chemical fixation, dehydration, and freeze-drying. The NanoSuit method enables FE-SEM observation of unfixed cells under a high vacuum environment by electron beam polymerization of extracellular substances called NanoSuit. It has been reported that a sample prepared by the NanoSuit method retains the morphological information of live cells better than a sample prepared by the conventional fixation method. Study design, size, duration This laboratory study was conducted with informed consent and IRB approval. Semen parameters were within the WHO normal reference range. Participants/materials, setting, methods The conventional fixation method sample was prepared by fixing (glutaraldehyde and osmium), dehydration (ethanol and t-butyl alcohol), and freeze-drying. The NanoSuit method sample was introduced into the FE-SEM directly without conducting the above treatments. For observation, a JSM–7100F (JEOL, Japan) was used at an acceleration voltage of 1.0 kV. The vacuum level of the observation chamber was 10–3 to 10–6 Pa. Main results and the role of chance Sperm head segmentation (acrosome, equatorial segment, and post acrosome), midpiece, and tail including endpiece could be clearly identified in the FE-SEM sample prepared by the NanoSuit method. Transmission electron microscopy revealed the existence of a thin polymerized extra layer, the NanoSuit, on the surface of the sperm. It is suggested that the presence of the NanoSuit layer enables FE-SEM observation of the unfixed sperm. The conventional fixation method causes a statistically significant contraction in the sperm head size compared to that calculated from optical micrographs (13.5 μm2 vs. 11.6 μm2, p < 0.001). Furthermore, wheat germ agglutinin (WGA), a lectin, which is known to have the ability to bind to the sperm surface, did not bind to the fixed FE-SEM samples. This means that the original cell surface properties are lost in the fixed sperm sample. On the other hand, the FE-SEM sample prepared by the NanoSuit method did not show a statistically significant contraction of the sperm head compared to that calculated from optical micrographs (13.2 μm2 vs 12.9 μm2, p = 0.416); it also revealed a detailed binding pattern of gold-labelled WGA to the sperm surface. These results indicate that the NanoSuit method can prepare FE-SEM samples without sperm contraction and denaturation. Limitations, reasons for caution Characteristic sperm morphology in patients with male infertility should be investigated in future studies. Wider implications of the findings: The NanoSuit method does not use chemical carcinogens and can prepare an FE-SEM sample in a shorter time than the conventional fixation method. The evaluation of ultrastructural morphology of unfixed sperms by this method may be useful for the identification of new morphological features and the evaluation of male infertility. Trial registration number Not applicable


2021 ◽  
Vol 560-561 ◽  
pp. 126043
Author(s):  
Mayumi Mujin ◽  
Michihiko Nakamura ◽  
Megumi Matsumoto
Keyword(s):  

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