• 생명과학회지
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• 제7권4호
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• pp.282-288
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• 1997

To obtain a basic information on the development of Genus Viola, ultrastructure and electrofusion process between the two protoplasts from wild Viola callus cells and pansy mesophyll cells were observed with a scanning electron microscopy(SEM) and transmission electron microscopy(TEM). In the ultrastructural observation of wild viola callus protoplasts and pansy mesophyll protoplasts using SEM, their cell walls were removed completely. A knob-like formation was observed on the enlarge surface of viola callus protoplasts. On the surface of pansy mesophyll protoplasts net-like chloroplasts were observed. In SEM observation of pansy mesophyll protoplasts, chloroplasts devoid of membrane were observed on the surface the protoplasts. Pearl chain was formed by applying AC field of 200 V/cm at 1.0 MHz for 43 sec. The lysis of plasma membranes and fusion process occurred by applying a 1,600 V/cm DC pulse twice for 1 sec. After 1-2 hours of a DC pulse application, it was observed that the two protoplasts were fused completely into one cell. In TEM observation of the fused cell, many small vacuoles were located in the fusion area of the two protoplasts. Indeed, two distinct regions were observed during fusing process; in one region, a nucleus was found, while in the other region, both nucleus and nucleous were found.

• Journal of the Korean Wood Science and Technology
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• 제36권6호
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• pp.96-104
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• 2008

본 연구에서는 고대 칠 기법을 규명하기 위하여 4가지 그룹의 표준칠편을 제작하여 광학현미경(투광, 낙사광, 편광)을 이용한 관찰을 실시하였다. 그룹 I 은 투명한 적갈색을 띠며 일부 층의 구분이 불명확하였고 연마가 된 층은 구분이 쉽게 되었다. 그룹 II는 대부분 투명 황갈색을 띠며 목재표면에 먼저 흑색안료를 메운 후 칠한 칠층과 흑색안료를 혼합하여 칠 한 칠층은 구분이 가능하였다. 그룹 III은 칠이 경화되는 과정에서 상층 부분이 먼저 막을 형성하고 내부는 칠과 불포화지방산이 산화 건조되어 상층의 칠층이 분리되어 관찰되었다. 그룹 IV의 칠도 막은 편광에서 관찰시 철 성분이 검은색과 붉은색으로 혼합되어 보이며 토분은 실리카 결정이 빛의 반사에 의하여 구분되어 졌다. 또한 석간주 칠층은 붉은색을 띠고 주칠과 석간주가 혼합된 칠은 윗부분과 아랫부분이 짙은 붉은 색을 띠며 가운데는 밝은 붉은색으로 구분되어 졌다.

• Restorative Dentistry and Endodontics
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• 제13권1호
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• pp.7-19
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• 1988

The object of this paper was to investigate the histopatological changes on dog's pulp under cavitation by irradiation of the $CO_2$ laser. The subjects were derived from four dogs, and irradiated 113.23 J/$mm^2$, 283.09 J/$mm^2$, 566.08 J/$mm^2$ in Group I, II, and III respectively. The dogs were sacrificed immediately, 24 hour, 72 hour and 1 week after $CO_2$ laser treatment. For light microscopic examination, routine H-E and PAS stains were employed. For electron microscopic observation, the teeth were fixed in 1% paraformaldehyde and 1% glutaraldehyde, decalcified teeth in 10% EDTA were stained by uranyl acetate and lead citrate. The observation was made with a Hitachi H-500 model electron microscope. The following results were obtained in this study: 1. At the early stage of the experimental sub-groups-immediately, 24 hour, 72 hour samples of Group I, II and III-coagulation necrosis and hyperemia were observed in odontoblastic and subodontoblastic pulpal layer. 2. At the 1 week sub-group of Group I, II, regenerative hyperplasia of the odontoblasts without coagulation necrosis were revealed, in addition to thickened predentin. On he other hand coagulation necrosis and atrophic change accompanying with hyperplasia were found at the 1 week sub-group of Group III. 3. Ultrastructurally, the odontoblasts appeared nuclear degeneration, vacuolar change of cytoplasmic organelles and rupture of plasma membrane at the early stage of the experimental period of all groups. 4. Under spectrohelioscopic examination, regenerative odontobalsts were seen at the 1 week specimens of Group I, II and III. 5. The pulpal response occured at 113-566 J/$mm^2$. The pathologic change of pulp tissue occured at the early experimental period but regeneration of odontoblasts could be seen after 1 week.

• 한국축산식품학회지
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• 제35권3호
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• pp.315-321
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• 2015

The aim of the present work was to investigate the effect of NaCl concentration on the emulsifying and rheological properties of porcine myofibrillar protein (MF)-stabilized soybean oil and fish oil emulsion (SO-EMs and FO-EMs). Emulsions (EMs) were prepared from 1% MF with 10% SO or FO at various NaCl concentration (0-0.5 M). The emulsifying ability index (EAI) of the EMs increased with increasing NaCl concentration for both oil types. Conversely, increasing NaCl manifested decrease in the emulsion stability index (ESI). In addition, creaming index (CI) also increased with NaCl concentration. From the microscopic observation, droplets of the EMs were more aggregated at relatively higher NaCl concentrations, especially for FO-EMs. All EMs had a gel-like structure owing to G' > G" from the rheological analysis. Comparing the oil types, the emulsifying capacity of SO-EMs was more stable than that of FO-EMs at all NaCl concentrations as determined from the CI value and microscopic observation. Therefore, it can be concluded that SO-EMs and FO-EMs are more stable at relatively lower concentrations of NaCl. In addition, the dispersed stability of SO-EMs was better than that of FO-EMs at the same concentration of NaCl.

• 한국물환경학회지
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• 제20권5호
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• pp.506-511
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• 2004

Maintaining dissolved oxygen (DO) at sufficiently low concentration in the aeration tank at a wastewater treatment plant (WWTP) is essential for reduction of the costs of operation and maintenance. On the other hand, the low DO level may result in adverse effect on the integrity of the activated sludge, A typical and disastrous outcome frequently experienced is the outgrowth of filamentous microorganisms, which is called as filamentous bulking, In addition to the traditional methods such as sludge settleability and microscopic observation of the culture, molecular techniques including polymerase chain reaction (PCR) amplification followed by 16S rRNA sequencing were applied to identify filamentous bacteria present in bulking sludge under a condition of low DO concentration, Two morphologically distinct groups, presumably consisting of Sphaerofilus nafans, and Eikelboom Type 1701 or Type 1851, were identified through microscopic observation. They were further confirmed by subsequent 16S rRNA sequencing. Dominant filamentous bacteria identified by the molecular techniques were consisted of three major groups. Sequences of partial 16S rRNA cloned showed that the filamentous bulking organisms were closely related to Eikelboom Type 021N and Eikelboom Type 1701, and Sphaerotilus natans, respectively. Molecular methods were found to possess a strong potential of direct examination of the microbial community of an activated sludge system.

• 동아시아식생활학회지
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• 제14권5호
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• pp.487-494
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• 2004

The effect of water extracts of Chungkukjang(WEC: 10%, w/v), which was prepared using Bacillus subtilis isolated from Korean traditional Chungkukjang, on the pH, acidity and volume of the dough, and loaf volume index(LVI), color, texture, retrogradation degree, microscopic observation and sensory quality of the bread were investigated. Experimental plots were divided to 3 groups(Control; without WEC, I; added 2.5% WEC against total amount of water, II; added 5.0% WEC against total amount of water). There were no significant difference in pH and acidity among each experimental groups. Dough volume were higher but LVI were lower in the 1- and II-bread than those of control group. L* values of the top crust and internal tissue in the I- and II-bread were lower than those of control group. The higher addition amounts had the lower L* values. Hardness, strength, gumminess and brittleness were higher, but cohesiveness and springiness were lower in the WEC-breads than those of control. In the results of microscopic observation, there were scarce of the bigger starch granules and a sparse structure, while there were smaller starch granules in the WEC-bread. The scores of crispy taste of the WEC-bread were lower than those of the control group, but there were no significant difference in tenderness, odor, savory taste and overall acceptability between the control and the I-bread. The retrogradation rate of the bread stored for 3 days at 25℃ was 45.09% in control, 17.92% in I-bread, and 12.45% in II-bread, respectively.

• 지질공학
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• 제11권2호
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• pp.191-203
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• 2001

포천 화강암에 대하여 결의 방향성에 따른 역학적 이방성 및 미세균열의 발달관계를 규명하였다. 일축압축강도는 177MPa∼212MPa의 범위를, 탄성계수는 48GPa∼62GPa, 인장강도는 6.9MPa∼8.5MPa, 탄성파 속도는 3,200m/sec∼3,700m/sec의 범위를 보인다. 이방성 비는 역학적 특성에 따라 최소 14%에서 최대 24%이며 1결에 의한 영향이 가장 크게 나타난다. 미세균열의 방향성은 결의 방향성과 상당한 연관성을 가진다. 그러나 장석 내에는 결정의 방향에 따라 미세균열들이 발달해 있어서 결의 방향과는 상당한 차이를 보이나, 석영 내에는 연장성이 매우 좋고 결의 방향과 거의 평행한 방향으로 많은 미세균열들이 발달해 있어서 석영 내에 발달한 미세균열의 방향성이 결의 방향을 지배하는 것으로 사료된다. 차분 변형률 분석과 현미경 관찰에 의한 미세균열의 방향성은 대체로 결의 방향과 상당히 유사하나, 각각의 측정 방법에 따라 약간의 차이를 보인다. 이러한 결과는 차분변형률이 미세균열의 폭을 측정하는 반면에 현미경 관찰은 길이나 개수를 측정하기 때문인 것으로 사료된다.

• Journal of Nutrition and Health
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• 제56권1호
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• pp.12-23
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• 2023

Purpose: This study investigates the alterations in A549 human non-small-cell lung cancer (NSCLC) cells exposed to Citrus junos extract (CJE). We further examine the antiproliferative and apoptotic effects of CJE on NSCLC cells. Methods: Inhibition of proliferation was examined by applying the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) colorimetric assay on CJE-treated A549 NSCLC cells. The lactate dehydrogenase (LDH) assay was performed to measure the degree of toxicity of CJE on NSCLC cells. The effect on migratory proliferation was confirmed using the scratch wound healing assay. The antiproliferative effect of the CJE on human lung cancer cells was verified through morphological observation, fluorescence microscopy, and caspase-3 colorimetry. Results: Exposure of NSCLC cells to CJE resulted in a dose- and time-dependent decrease in cell activity and increased toxicity to the cells. In addition, microscopic observation revealed a reduced ability of the cancer cells to migrate and proliferate after exposure to the CJE, with simultaneous morphological apoptotic changes. Fluorescence staining and microscopic examination revealed that this death was a process of self-programmed cell death of NSCLC cells. Compared to unexposed NSCLC cells, the expression of caspase-3 was significantly increased in cells exposed to CJE. Conclusion: Exposure of A549 human NSCLC cells to CJE inhibits the proliferation, increases the cytotoxicity, and decreases the ability of cells to migrate and grow. Moreover, the expression of caspase-3 increases after CJE treatment, suggesting that the apoptosis of NSCLC cells is induced by a chain reaction initiated by caspase-3. These results indicate that Citrus junos is a potential therapeutic agent for human non-small-cell lung cancer.

• Applied Microscopy
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• 제38권4호
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• pp.285-291
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• 2008

Electron tomography의 정량적 분석을 위해서 대물렌즈 조리개가 투과빔의 강도에 미치는 영향을 평가하였다. Electron tomography에 도입되는 Beer's law의 올바른 적용을 위해서는 투과빔은 시료의 기울기에 따른 mass thickness의 변화에 의한 효과만을 반영해야 한다. 그러므로 빔 경로상의 대물렌즈 조리개, 홀더 등에 의한 다른 효과는 제거되어야 한다. 본 연구에서는 대물렌즈 조리개의 cut-off 효과를 120 kV TEM과 Quantifoil holey 카본 시료를 이용하여 상세히 평가하였다. 대물렌즈 조리개를 사용하지 않은 경우와 비교할 때, $30{\mu}m$ 크기의 대물렌즈 조리개를 통과한 투과전자빔의 강도는 약 16.7%의 감소가 일어난다. 또한 $55^{\circ}$ 이상의 고경사각 기울기에서는 대물렌즈 조리개의 cut-off 효과에 의해 14.2%의 강도 감소가 추가적으로 발생함을 알 수 있었다. Electron tomography에서 정량 분석을 위해서는 이러한 대물렌즈 조리개의 영향을 고려해야만 한다. 또한 Beer's law의 올바른 적용을 위해서는 일련의 기울기에 따른 2차원적 영상은 가능하면 대물렌즈 조리개를 사용하지 않은 상태에서 획득하는 것이 바람직하다.

• 한국어병학회지
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• 제32권2호
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• pp.123-127
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• 2019

In this study, white spots appearing in carapace of imported white leg shrimp Litopenaeus vannamei were observed by macroscopic and microscopic examination. White spots due to white spot disease showed two types, white spots with a regular circular shape ranging from 0.4 mm to 1.7 mm and white spots with an irregular shape ranging from 0.05 mm to 2 mm. White spots due to other causes showed four types that appeared as crystalized materials in range of 100 ㎛ around the tegumental gland, as polygonal inorganic deposits ranging from 58 ㎛ to 188 ㎛, as Linear inorganic deposits ranging from 0.8 mm to 9 mm, as brownish spots ranging from 0.1 mm to 0.4 mm, and brownish spots containing melanin ranging from 0.1 mm to 2 mm. As a result, white spots occurred in imported white leg shrimp Litopenaeus vannamei were divide two type, due to white spot disease or other causes, for quarantine works.