• Journal of the Korean Wood Science and Technology
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• 제48권6호
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• pp.780-790
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• 2020

본 연구에서는 낙엽송 열처리재의 세포벽 미세구조와 항팽윤효율을 평가하고, 이들 간의 상호관계를 분석하고자 하였다. 이를 위하여 낙엽송 판재를 190℃와 220℃의 온도 조건에서 12시간, 18시간, 24시간 동안 열처리하였다. 열처리된 낙엽송재의 횡단면을 1,000배 확대하여 관찰한 결과, 열처리재의 경우 세포가 원래의 형태를 유지하지 못 했으며, 세포의 단면이 거칠게 절단되었고, 세포 간 결합이 끊어지면서 세포간극이 늘어났음을 확인할 수 있었다. 또한, 처리 조건 별 팽윤 실험 결과, 열처리 온도와 시간이 증가함에 따라 수분 흡수량과 팽윤량이 감소하였으며, 항팽윤효율은 증가하는 경향을 보였다. 수분 흡수량의 감소는 열처리에 의한 세포벽의 화학적 변화에 영향을 받은 것으로 보이며, 팽윤량의 감소 및 항팽윤효율의 증가는 화학적 변화 뿐만 아니라 세포벽의 구조적인 변화와 같은 물리적인 변화가 복합적으로 영향을 미쳤기 때문인 것으로 생각된다.

• Plant Resources
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• 제3권3호
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• pp.163-172
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• 2000

We compared microstructural features of the ordered cell and disordered leaves in Citrus junos Sieb. by electron microscopy. In the cell of the ordered leaves, many chloroplasts and large vacuoles were particularly observed. Also a lot of vessel, companion cell and big nucleus were presented in vascular bundle regions. The mitochondria and the other organelles were interspersed among the chloroplasts in a thin, peripheral layer of cytoplasm. The chloroplast possessed typical grana and intergranal lamellae, numerous starch grains and a few small osmophilic globules. Besides, microbodies were closely associated with the mitochondria and the chloroplast. The process of the formation of the secondary cell wall from primary cell wall was observed the vessel elements, the tonoplast wall and the secondary cell wall. It was observed that the oil sac with the unique perfume distributed the adjacent cell wall. In the cell of disordered leaves, the all of the organelles were thrust toward the cell wall due to the fusion of vacuoles in the cells. It was observed that a lot of the very small particles spreaded in the cytoplasm. The loss of unique perfume of the leaves was resulted in the destruction of the oil sac. Also, there was not observed grana, lamellae, starch and osmophillic globules in the chloroplast. The small distributed organelles was not observed but the elongation of the cell wall was proceed no longer. Therefore, the plasma membrane diverged from the cell wall. All of organelles in the cell had poor function and deformation. A massive vacuole was fulfilled in single cell and the vacuole contains a lot of large and small particles. The organelles were presented on the side of the cell wall according to the enlargement of vacuole and they were observed to be breakdown.

• 한국분말재료학회지
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• 제27권2호
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• pp.119-125
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• 2020

One of the promising candidates for accident-tolerant fuel (ATF), a ceramic microcell fuel, which can be distinguished by an unusual cell-like microstructure (UO₂ grain cell surrounded by a doped oxide cell wall), is being developed. This study deals with the microstructural observation of the constituent phases and the wetting behaviors of the cell wall materials in three kinds of ceramic microcell UO₂ pellets: Si-Ti-O (STO), Si-Cr-O (SCO), and Al-Si-Ti-O (ASTO). The chemical and physical states of the cell wall materials are estimated by HSC Chemistry and confirmed by experiment to be mixtures of Si-O and Ti-O for the STO; Si-O and Cr-O for SCO; and Si-O, Ti-O, and Al-Si-O for the ASTO. From their morphology at triple junctions, UO₂ grains appear to be wet by the Si-O or Al-Si-O rather than other oxides, providing a benefit on the capture-ability of the ceramic microcell cell wall. The wetting behavior can be explained by the relationships between the interface energy and the contact angle.

• Preventive Nutrition and Food Science
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• 제11권1호
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• pp.61-66
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• 2006

The objective of this study was to compare the color and microstructure of powder, redness, brownness, and antioxidative activity in extruded ginseng, white ginseng and red ginseng extracts. The colors of extruded dry ginseng powder (moisture content 30%, barrel temperature $110^{\circ}C$, and screw speed 200 rpm) were similar to those of red ginseng. Intact cell wall structure was examined in dried root ginseng at $70^{\circ}C$ (A), white ginseng with skin (D), white ginseng without skin (E), and red ginseng (F) under a scanning electron microscope. The cell wall was not detected in samples B and C (dry ginsengs extruded with 25% and 30% moisture contents, respectively). Intact starch granules were detected in samples A, D, and E under a scanning electron microscope. Melted starch granules were detected in samples B, C, and F. Colors (L, a, b) of 50% EtOH extracts were similar in samples C and F. Browniness and redness of extracts were high in extruded dry ginseng and red ginseng extracts. Extruded dry ginseng (B) showed higher electron donation ability and phenolic content than the other samples.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.549-576
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• 1995

Bacteria are one of the most important causative agents of the pulpal and periapical diseases. Streptococci are one of the most frequently isolated facultative anarerobic bacteria in the infected root canals. Bacterial cell wall components have a direct effect in the pathogenesis of the pulpal and periapical infections. Hyaluronidase produced by bacteria has been implicated in dissemination of the diseases. The purpose of this study was to evaluate the effect of cell wall extract of streptococci on the L929 cells using inverted microscope and the transmission electron microscopy (TEM). Hyaluronidase production of streptococcal strains were investigated to determine the correlation between the severity of cell damage and the activity of enzymes. Bacterial cell wall extracts of S. sanguis, S. mitis and S. uberis isolated from infected root canals and ATCC type strains of S. mutans (ATCC 10449) and E. faecalis (ATCC 19433) were prepared by sonication and confirmed with SDS-PAGE. Silver stain of SDS-PAGE of sonic extract was efficient at $100{\mu}g$/ml concentration of cell wall protein, while Coomasie blue stain was efficient at $100{\mu}g$/ml concentration. Inverted microscope showed that sonic extract-treated L929 cells were round and detached from the substratum while others lost their fibroblastic shapes. Transmission electron microscopic examination revealed that streptococcal extracts induced death of L929 cells. Sonic extracts of streptococci had variable effect on microstructure of L929 cells. significant chromatin condensation was observed in the nucleus of the cells. Disappearance of cell surface microvilli and nuclear fragments with dense chromatin were observed. The cell nucleus had an irregular shape and numerous large vacuoles were seen in the cytoplasm and some breaks of the cell membrane could be seen. Cell organelles were in various stages of destruction and cristae of mitochondria were disoriented or disappeared. Eighteen strains of streptococci did not produce hyaluronidase.

• Journal of Plant Biology
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• 제39권2호
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• pp.137-144
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• 1996

Scanning electron microscope revealed several taxonomically useful characters in the perigynium and achene epidermis of sect. Siderosticatae (Carex siderosticta, C. ciliatomarginata and C. okamotoi). Mocroscopic characters such as perigynium shape, hair presence or absence, beak shape, nodule situation in perigynium, achene shape, cell wall and silica cone in achene were useful in Carex at the species levels. A key was presented on the basis of features obtained from the examinations.

• 한국분말재료학회지
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• 제19권4호
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• pp.278-284
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• 2012

$Al_2O_3$ foam is an important engineering material because of its exceptional high-temperature stability, low thermal conductivity, good wear resistance, and stability in hostile chemical environment. In this work, $Al_2O_3$ foams were designed to control the microstructure, porosity, and cell size by varying different parameters such as the amount of amphiphile, solid loading, and stirring speed. Particle stabilized direct foaming technique was used and the $Al_2O_3$ particles were partially hydrophobized upon the adsorption of valeric acid on particles surface. The foam stability was drastically improved when these particles were irreversibly adsorbed at the air/water interface. However, there is still considerable ambiguity with regard to the effect of process parameters on the microstructure of particle-stabilized foam. In this study, the $Al_2O_3$ foam with open and closed-cell structure, cell size ranging from $20{\mu}m$ to $300{\mu}m$ having single strut wall and porosity from 75% to 93% were successfully fabricated by sintering at $1600^{\circ}C$ for 2 h in air.

• 한국식품과학회지
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• 제19권2호
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• pp.164-170
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• 1987

강남콩과 대두를 삶아 분리한 고물의 미세구조를 광학 현미경 및 SEM으로 조사하고 그 화학조성과 조직감 특성을 비교하였다. 강남콩 고물의 경우 각각의 세포가 잘 분리되었으나 대두 고물은 여러개의 세포가 결학된 덩어리가 많이 포함되어 있었다. SEM 사진에 의하면 강남콩 고물을 구성하는 세포는 구형이었으나 대두 고물의 구성세포는 긴 자루 형태를 가지고 있었다. 펙틴질을 비교적 많이 함유하는 대두 고물의 경우 높은 접착성과 응집성을 나타내었다.

• 한국식품과학회지
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• 제17권6호
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• pp.454-459
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• 1985

루핀콩(lupinus angustifolius)의 식품으로서의 가치를 평가하기 위한 형태학적 접근방법의 하나로써 취반시(時) 일어나는 미세구조적 변화를 대두와 비교하였다. 루핀공은 대두에 비해 두꺼운 세포벽과 pit-pair을 가지며 protein body안에 많은 crystaloid를 포함하고 있어, oil seed인 대두와는 상당히 다른 자엽구조를 보여 주었다. 또한 대두에서는 높은 온도($120^{\circ}C$)로 가열했을 때 (20분) middle lamella 구조의 파괴와 함께 세포벽의 손상이 명백하였으나, 루핀콩의 경우 $120^{\circ}C$에서 장시간(130분) 가열했을 때에도 세포벽의 파괴 및 middle lamella의 파괴없이 본래의 자엽세포 구조를 유지하였다.

• 한국조리학회지
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• 제12권4호
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• pp.299-319
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• 2006

The purpose of this study was to investigate the changes of hardness and microstructure of Dongchimi cooked with various sources of sugar(xylitol, xylose, sugar, pear juice). It was fermented at $10^{\circ}C$ for 60 days. The changes of pH in Dongchimi used different kinds of sugar decreased in all samples during the fermentation period, and then showed a slow decrease after 12 days of fermentation. The total acidity of Dongchimi using xylitol arrived slowly at the best tasting condition($0.3\sim0.4$ point) compared with other conditions. The changes of salt content were showed high as compared with other test conditions in 0 day, the day of fermentation. At the early stage of fermentation, the changes of turbidity of Dongchimi using sugar, pear juice were showed high as compared with those of Dongchimi using xylitol, xylose for $5\sim15$ days of fermentation. The maximum cutting force of Chinese radish Dongchimi showed the highest value among al at the 25 th day of ripening and then decreased gradually. The maximum cutting force of Dongchimi using sugar showed the lowest. The calcium and magnesium contents of Dongchimi juice and Chinese radish Dongchimi juice using xylitol were observed high at the early stage of fermentation and showed the highest value during the fermentation period. The microstructure showed disintegration appearance of middle lamella and cell wall during the fermentation period.