• Applied Microscopy
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• 제52권
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• pp.12.1-12.8
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• 2022

The microstructure of diatom frustules found in mud sediments along the coast of Boryeong- city, South Korea, was observed using a scanning electron microscopy (SEM), and the constituent elements of diatoms were analyzed using energy-dispersive X-ray spectroscopy (EDS). Diatom frustules and clay minerals were present in the SEM images of the mud powder. High-magnification SEM images revealed that the surface of the frustules contained identically shaped circular pores, measuring 1 ㎛ in diameter, arranged at regular intervals. This study revealed that the diatom shell fragments in the mud powder ranged in size from 3 to 30 ㎛, with an average thickness of approximately 2.5 ㎛. The elements Si, Al, Fe, K, Na, Mg, and Ti were detected while analyzing the frustule constituents, with Si being the primary component with the highest content.

• 한국환경성돌연변이발암원학회지
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• 제23권3호
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• pp.99-102
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• 2003

IARC classified areca quid as a human carcinogen. Areca quid chewed in Taiwan includes Piper betle inflorescence, which contains high concentrations of safrole (15 mg/fresh weight). Safrole is a documented rodent hepatocarcinogen, and chewing areca quid may contribute to human exposure (420 $\mu$m in saliva). The carcinogenicity of safrole is mediated through 1'-hydroxysafrole formation, followed by sulfonation to an unstable sulfate that reacts to form DNA adducts. Using human liver microsomes and Escherichia coli membranes expressing bicistronic human P450s, CYP2E1 and CYP2C9 were identified as the main P450s involved in the activation of safrole. We have demonstrated the presence of stable safrole-dGMP adducts in human oral tissues following areca quid chewing using $^{32}$ P-postlabeling and HPLC mass spectrometry methods. By studying 88 subjects with a known AQ chewing history and 161 matched controls, we have demonstrated that the presence of safrole-DNA adducts in peripheral blood cells was correlated to AQ chewing, and CYP2E1 seemed to play an important role in the modulation of safrole-DNA adduct formation. We have also shown that safrole can form stable safrole-DNA adducts as well as oxidative damages in rodent liver. However, the stable safrole-DNA adducts may represent a more significant initial lesion as compared to the rapidly repaired safrole-induced 8-hydroxy-2'-deoxyguanosine. This oxidative DNA damage is mediated through the formation of hydoryxchavicol, the major safrole metabolite in human urine. Hydroxychavicol may have gone through two-electron oxidation to the o-quinone; then via one-electron reduction to semiquinone radicals to generate oxidative DNA damage. However, these reactive metabolites can be efficiently conjugated by GSH. These data suggest that safrole may contribute to the initiation of oral carcinogenesis through safrole-DNA adduct and not oxidative DNA damage. In addition, CYP2E1 may modulate this adduct formation.

• 대한치과보철학회지
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• 제36권1호
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• pp.50-63
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• 1998

This study investigated the effects of resin surface primers for rebase resins on the surface texture of denture base resins by the use of scanning electron microscopy. This study also evaluated the bond strength of rebase resins to denture base resin. The denture base resin in this study was Vertex RS (Dentimex Co., Ltd., Holland). The rebase resins used were Tokuso Rebase (Tokuyama Co., Ltd., Japan), Metabase (Sun Medical Co., Ltd., Japan), New True Liner(Harry J, Bosworth Co., Ill.), and Reverse (Nissin Co., Ltd., Japan). The test samples were divided into four parts: Group 1 : Treated with primer with brush. Group 2 : Immersed in the primer for 5 seconds. Group 3 : Immersed in the primer for 10 seconds. Group 4 : Immersed in the primer for 30 seconds. Control group : not treated with primer The results were as follows; 1. The bond strength of rebase resins to denture base resin is increased by application of primers. 2. Regardless of the rebase resin type, there was no significant difference among the bond strength in groups G1, G2, G3, G4. There was a significant difference with the control. (P<0.05) 3. Regardless of each group, the bond strength according to the rebase resin type was decreased in the following order: Tokuso Rebase, New Tru Liner, Reverse and then Metabase. 4. Under the scanning electron microscope, brush application produced a softening of the denture base surface. After immersion, all primers produced a spongelike structure on the denture base resin surface. The results of this study suggest that primers produce a significant effect by means of brush application, therefore it is recommended as the most convenient and logical procedure for application of the primers.

• Applied Microscopy
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• 제20권1호
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• pp.105-119
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• 1990

In order to know the morphological characteristics and changes according to the developmental stage, the comparative observations have been studied by light and electron microscope on the midgut(gastric caecum, stomach) of the grasshopper(Oxya sinuosa Mistshenko). The results obtained are summarized as follow : In light microscopic level, the cuboidal shaped cells of the gastric caecum in the 5th instar nymph are differentiated the columnar epithelium in the adult. A number of pigment granules are appeared in the gastric caecum of the 5th instar nymph, however the pigment granules were absent in the adult. Indistinct or undifferentiated folds of the epithelial layer were appeared in the 5th instar nymph, whereas the well-developed folds were appeared the gastric caecum in the adult. The well-developed muscular layers are seen in the 5th instar numph, however in the adult the muscular layers are appeared thin or a few layers. In electron microscopic level, in the midgut epithelium, a number of well-developed rER, a few lipid droplets, multi vesicular bodies, small vesicles and glycogen granules were found. Two types of the pigment granules in the gastric caecum of the 5th instar nymph were appeared, whereas the whorl-membrane, a few secretory granules and one type of the gastro-entero-endocrine cell were found in the adult midgut. The light and dark cells could be distinguished in the stomach epithelim of the 5th instar nymph.

• Applied Microscopy
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• 제39권2호
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• pp.199-204
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• 2009

본 연구는 펌 염색을 한 번도 경험하지 않은 13세의 건강한 여성의 모발에 펌을 반복 시술하여 모발 표면의 형태적 변화를 주사전자현미경을 사용하여 관찰하였다. 펌1차 시술한 모발 표면은 큐티클 세포의 끝 부분들이 불규칙하게 쪼개져 나갔으며, 비늘의 가장자리 끝부분이 거칠은 상태로 관찰되었다. 그리고 큐티클세포들이 분리되고 공간이 형성되면서 표면 쪽으로 부풀어 오른 것을 확인하였다. 펌3차 시술한 모발의 경우에는 모발 표면에서 큐티클 세포와 세포 사이가 들떠서 분리되어 있고 중첩된 큐티클층 표면에 중첩된 비늘은 표면적이 불규칙하게 나타났다. 표면에 부서진 큐티클 세포의 세포질 일부가 부착되어 있으며 세포질 내의 내큐티클에는 공포가 형성되어 있었다. 펌의 횟수가 증가할수록 큐티클층과 피질의 분리가 쉽게 일어나는 것을 확인하였다.

• 대한한방내과학회지
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• 제23권2호
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• pp.191-201
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• 2002

Objectives : This study was designed to investigate the effects of Yukmijihwang-tang on contusion of the mice induced with medicine. Methods : I observed the effects of light and electron microscopes. and examined hematological changes and VEGF-immunohistochemistry. Results : Hematology: Leukocytes were increased significantly in a control group of mice compared with the experimental group. Light microscope : A few neurons were condensed in the 7-day experimental group, but condensed remarkedly in the 3-day control group. Most glial cells were observed in the 3-day experimental group. Edema and dilatation of vessels occurred significantly in the 3-day control group, and these results occurred weakly in the 7-day experimental group. VEGF-immunohistochemistry : VEGF-immunohistochemical reactivity for the glial cells was the highest in the 3-day experimental group, and immunoreactivity for the vessels and neurons highly increased in the 7-day experimental group. Electron microscope : In the 3-day control group, protoplasmic astrocytes concerned with angiogenesis contained weakly developed rough endoplasmic reticulum. and a few of glial filaments were observed. In the 7-day experimental group, the bundles of glial filaments were found in the cytoplasmic process of astrocytes. Conclusion : medication using Yukmijihwang-tang of mice contused by medical stress is highly effective in inflamatory response, curing cell damage and angiogenesis.

• 한국분말재료학회지
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• 제18권1호
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• pp.14-17
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• 2011

$TiO_2$ nanopowders with anatase structure were firstly prepared by controlling the pH value of a precursor solution without any heat-treatment at room temperature. The prepared $TiO_2$ nanopowders were hydrothermally treated in 10M NaOH solution at $170^{\circ}C$. Then, the samples were washed in DI water or 0.1M HCl. The $TiO_2$ nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The gas sensitivity of $TiO_2$ nanotubes for toluene gas was also investigated. The results show that $TiO_2$ nanotubes can be prepared by hydrothermal treatment. The morphology of $TiO_2$ nanotubes prepared by 0.1M HCl washing is destroyed to some extent. $TiO_2$ nanotubes with DI water washing show better sensitivity than that with 0.1M HCl washing.

• Applied Microscopy
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• 제31권4호
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• pp.307-314
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• 2001

12주령 랫드의 비골의 골절을 유발한 후 골절치유에 미치는 홍화씨 분말의 영향을 알아보고자 실험을 실시한 결과 다음과 같은 결과를 얻었다. 비골의 골절은 골절유발 후 5주에 성숙된 신생골 조직으로 충만되어 조직형태학적으로 완전한 유합이 이루어지는데, 홍화씨 분말을 투여한 결과 골절유발 후 4주에 성숙된 신생골 조직으로 골절단이 충만되어 완전한 유합을 이룬 후 5주에서는 골수강도 개통되는 등 대조군과 비교하여 유합시기를 기준으로 1.5주 정도의 빠른 골절의 치유가 이루어졌다. 이상의 결과는 홍화씨 분말에 골절의 치유를 촉진시키는 성분이 포함되어 있을 가능성을 시사한다고 사료된다.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1633-1638
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• 2014

[6]-Gingerol is known as the major bioactive constituent of ginger. In the study, it was observed to effectively protect against ${\bullet}OH$-induced DNA damage ($IC_{50}$ $328.60{\pm}24.41{\mu}M$). Antioxidant assays indicated that [6]-gingerol could efficiently scavenge various free radicals, including ${\bullet}OH$ radical ($IC_{50}$ $70.39{\pm}1.23{\mu}M$), ${\bullet}O_2{^-}$ radical ($IC_{50}$ $228.40{\pm}9.20{\mu}M$), $DPPH{\bullet}$radical ($IC_{50}$ $27.35{\pm}1.44{\mu}M$), and $ABTS{^+}{\bullet}$radical ($IC_{50}$ $2.53{\pm}0.070{\mu}M$), and reduce $Cu^{2+}$ ion ($IC_{50}$ $11.97{\pm}0.68{\mu}M$). In order to investigate the possible mechanism, the reaction product of [6]-gingerol and $DPPH{\bullet}$ radical was further measured using HPLC combined mass spectrometry. The product showed a molecular ion peak at m/z 316 $[M+Na]^+$, and diagnostic fragment loss (m/z 28) for quinone. On this basis, it can be concluded that: (i) [6]-gingerol can effectively protect against ${\bullet}OH$-induced DNA damage; (ii) a possible mechanism for [6]-gingerol to protect against oxidative damage is ${\bullet}OH$ radical scavenging; (iii) [6]-gingerol scavenges ${\bullet}OH$ radical through hydrogen atom ($H{\bullet}$) transfer (HAT) and sequential electron (e) proton transfer (SEPT) mechanisms; and (iv) both mechanisms make [6]-gingerol be oxidized to semi-quinone or quinone forms.

• The Journal of Advanced Prosthodontics
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• 제10권3호
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• pp.197-204
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• 2018

PURPOSE. To determine the extent of treatment traces, the roughness depth, and the quantity of titanium nitride (TiN) removed from the surface of CAD/CAM abutments after treatment with various instruments. MATERIALS AND METHODS. Twelve TiN coated CAD/CAM abutments were investigated for an in vitro study. In the test group (9), each abutment surface was subjected twice (150 g vs. 200 g pressure) to standardized treatment in a simulated prophylaxis measure with the following instruments: acrylic scaler, titanium curette, and ultrasonic scaler with steel tip. Three abutments were used as control group. Average surface roughness (Sa) and developed interfacial area ratio (Sdr) of treated and untreated surfaces were measured with a profilometer. The extent of treatment traces were analyzed by scanning electron microscopy. RESULTS. Manipulation with ultrasonic scalers resulted in a significant increase of average surface roughness (Sa, P<.05) and developed interfacial area ratio (Sdr, P<.018). Variable contact pressure did not yield any statistically significant difference on Sa-values for all instruments (P=.8). Ultrasonic treatment resulted in pronounced surface traces and partially detachment of the TiN coating. While titanium curettes caused predominantly moderate treatment traces, no traces or detectable substance removal has been determined after manipulation with acrylic curettes. CONCLUSION. Inappropriate instruments during regular plaque control may have an adverse effect on the integrity of the TiN coating of CAD/CAM abutments. To prevent defects and an increased surface roughness at the transmucosal zone of TiN abutments, only acrylic scaling instruments can be recommended for regular maintenance care.