• The Korean Journal of Pesticide Science
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• v.6 no.2
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• pp.96-104
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• 2002

This study was carried out to investigate cytotoxicity of paraquat on NIH 3T3 fibroblasts, toxicity of paraquat and compensatory effects of 3-methylcholanthrene (3-MC) on the rat lung. In order to conduct MIT [3-(4,5-Dimethylthiazol-2-yl) -2,5-diphenyl -2H-tetrazolium-bromide] and NR (Neutral red) assay, the $5.0{\times}10^4cell/ml$ of NIH 3T3 fibroblast in each well of 24 multi-dish were cultured. After 24 hours, the cells were treated with solution of paraquat (1, 25, 50 and $100{\mu}M$ respectively). After the NIH 3T3 fibroblast of all groups were cultured in same condition for 48 hours. MIT and NR assay were performed to evaluate the cytotoxicity of cell organelles. $MTT_{50}\;and\;NR_{50}$ of paraquat were $1668.97{\mu}M\;and\;1030.85{\mu}M$, respectively. These $IC_{50}$ of Paraquat were decided as a low cytotoxicity by Borenfreund and Puemer (1984). In order to observe the toxicity and compensatory effects of paraquat on the rat lung, Spraque Dawley male rats were used as experimental animals and were divided into paraquat only treated group and simultaneous application group of paraquat and 3-MC, at 30 min and 1, 3, 6, 12, 24, 48 and 96 hrs interval after each treatment. The animals were sacrificed by decapitation and their or the lungs were immediately removed, immersed in fixatives, and were processed with routine method for light microscopic study. Paraffin sections were stained with H&E and iron hematoxylin of Verhoeff. Under the light microscopy, erythrocytes were full in alveolar capillaries at 3 hrs and congested at 24 hrs after paraquat administration. The great alveolar cells (Type II cell) were increased and mitosis of great alveolar were observed in interalveolar septa. Many lymphocytes, macrophages and polymorphonuclear (PMN) cells were observed in connective tissue surrounding lung tissue and germinal center in lymph follicles of terminal bronchiole. Alveolar macrophages were increased in interalveolar septa and alveoli at 48 hrs. And observed many alveolar macrophages at 96 hrs. In iron hematoxylin stain of Verhoeff, Collagen fiber were increased in respiratory bronchiole, interalveolar septa and alveoli and breath of alveoli, and alveolar pore were broaden. But, in paraquat plus 3-MC treated group, morphological changes were mild in lung tissue. These results indicate that 3-MC has a compensatory effects against toxicity of paraquat by conjugation with oxygen.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.1-23
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• 2001

Chitosan is biodegradable natural polymer that has been demonstrated its ability to improve wound healing, and calcium metaphosphate(CMP) is a unique class of phosphate minerals having a polymeric structure. In this study, chitosan/CMP and platelet derived growth factor(PDGF-BB) loaded chitosan/CMP sponges were developed, and the effect of the sponges on bone regeneration and their possibility as scaffolds for bone formation by three-dimensional osteoblast culture were examined. PDGF-BB loaded chitosan/CMP sponges were prepared by freeze-drying of a mixture of chitosan solution and CMP powder, and soaking in a PDGF-BB solution. Fabricated sponge retained its 3-dimensional porous structure with $100-200\;{\mu}m$ pores. The release kinetics of PDGF-BB loaded onto the sponge were measured in vitro with $^{125}I-labeled$ PDGF-BB. In order to examine their possibility as scaffolds for bone formation, fetal rat calvarial osteoblastic cells were isolated, cultured, and seeded into the sponges. The cell-sponge constructs were cultured for 28 days. Cell proliferation, alkaline phosphatase activity were measured at 1, 7, 14 and 28 days, and histologic examination was performed. In order to examine the effect on the healing of bone defect, the sponges were implanted into rat calvarial defects. Rats were sacrificed 2 and 4 weeks after implantation and histologic and histomorphometrical examination were performed. An effective therapeutic concentration of PDGF-BB following a high initial burst release was maintained throughout the examination period. PDGF-BB loaded chitosan/CMP sponges supported the proliferation of seeded osteoblastic cells as well as their differentiation as indicated by high alkaline phosphatase activities. Histologic findings indicated that seeded osteoblastic cells well attached to sponge matrices and proliferated in a multi-layer fashion. In the experiments of implantation in rat calvarial defects, histologic and histomorphometric examination revealed that chitosan/CMP sponge promoted osseous healing as compared to controls. PDGF-BB loaded chitosan/CMP sponge further echanced bone regeneration. These results suggested that PDGF-BB loaded chitosan/CMP sponge was a feasable scaffolding material to grow osteoblast in a three-dimentional structure for transplantation into a site for bone regeneration.

• Applied Microscopy
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• v.38 no.2
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• pp.117-124
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• 2008

Salvinia is an aquatic plant forming dimorphic leaves that have been modified into floating and submerged leaves. A air of floating leaves plays an important role for the floating and photosynthesis while the submerged leaves, which are lim and long, have the form and function of root. Many aquatic plants develop trichomes in the epidermis but in Salvinia, richomes grow densely in the epidermis of the dimorphic leaves. The present study examined the differentiation pattern of trichomes developing in the floating leaves of S. natans and S. molesta by scanning and transmission electron microscopy. Trichomes developing in the floating leaves of Salvinia showed very different patterns. In S. natans, they were arranged in a V-shape form, having 20${\sim}$25 rows at $18{\sim}25^{\circ}$ on both sides of the lamina divided by the midrib in the floating leaf. In each row, 8${\sim}$10 oval-shaped cells, $200{\sim}290{\mu}m$ in length, were arranged in a spiral fashion. Four trichomes of this form made a trichome unit, but their apical parts were separated from one another and developed into the so-called 'knuckle-crane' type. On the other hand, in S. molesta, trichomes differentiated in a unique pattern quite different from those of S. natans. At the early stage of differentiation, trichomes protruded from the epidermis and then 4${\sim}$6 cylindrical cells grew $400{\sim}600{\mu}m$ long and the four trichomes formed as an unit. The four grouped trichomes were interconnected through their apex and developed in the 'egg-beater' type. Then $300{\sim}600{\mu}m$ long multi-cellular stalk cells grew and protruded out of the epidermal surface from the basal part of the trichomes. Such a structural characteristic of trichomes is considered to play a very important role along with the aerenchyma tissue in the leaf mesophyll tissue for the floating of Salvinia on the water surface.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.190-201
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• 1980

This experiment was designed to optimize the process of manufacturing the soybean cheeses and to elucidate the chemical changes during ripening when the chemical changes during ripening when the milk components and enzyme preparations were added to the raw materials. Conditions for extracting soybean protein such as temperature, duration and amount of water added were determined; various coagulaters were compared by checking the curd texture and yield; starters from S. thermophilus, S. lactis MLB and S. cremoris EB-9 were tested as single- or multi-stain combinations; and the effects of skim milk and/or rennins-both microbial and calf origin-addition upon the process of manufacturing and ripening were studied. The results obtained were as follows. 1. optimal conditions for soybean extraction were found to be: temperature $100^{\circ}C$, duration 10 minutes, and amount of water added 9-fold, as considered the extraction rate of solids and proteins, and curd yield. 2. Sodium gluconate was the most effective among the coagulators tested, and 5% of single-strain starter from S. thermophilus was appered to be adequate inoculum for curd formation. 3. The effects of skim milk and/or rennins addition on the process of manufacturing and ripening of soybean cheeses were: 1) The addition of rennins resulted in fast formation of curd, especially with skim milk it was so. And Hansen rennet extracts brought better results in curd formation than Meito rennet extracts did. 2) No significant effect was observed on the changes in moisture content during ripening, however the levels of moisture contents in the products were higher in case of using Meito rennet extracts. 3) Effect on pH changes during ripening was also not significant in general, while levels of pH were decrease markedly during manufacturing and the initial stage of ripening. 4) The levels of bacterial counts were much higher in case of skim milk addition throughtout the ripening period. In general the numbers were reached to approximately $10^8cells/g$ during manufacturing, then decreased gradually to below $10^2cells/g$ in 8 weeks of ripening. 5) The addition of skim milk and/or rennin resulted in higher ripening index, and skim milk plus Meito rennet extracts was appeared to be best combination for the ripening index.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.283-287
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• 2007

KIER has been developing the anode-supported flat tubular solid oxide fuel cell unit bundle for the intermediate temperature($700{\sim}800^{\circ}C$) operation. Anode-supported flat tubular cells have Ni/YSZ cermet anode support, 8 moi.% $Y_2O_3$ stabilized $ZrO_2(YSZ)$ thin electrolyte, and cathode multi-layer composed of Sr-doped $LaSrMnO_3(LSM)$, LSM-YSZ composite, and $LaSrCoFeO_3(LSCF)$. The prepared anode-supported flat tubular cell was joined with ferritic stainless steel cap by induction brazing process. Current collection for the cathode was achieved by winding Ag wire and $La_{0.6}Sr_{0.4}CoO_3(LSCo)$ paste, while current collection for the anode was achieved by using Ni wire and felt. For making stack, the prepared anode-supported flat tubular cells with effective electrode area of $90\;cm^2$ connected in series with 12 unit bundles, in which unit bundle consists of two cells connected in parallel. The performance of unit bundle in 3% humidified $H_2$ and air at $800^{\circ}C$ shows maximum power density of $0.39\;W/cm^2$ (@ 0.7V). Through these experiments, we obtained basic technology of the anode-supported flat tubular cell and established the proprietary concept of the anode-supported flat tubular cell unit bundle.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.82.1-82.1
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• 2010

수소화된 비정질 실리콘 박막을 이용한 반도체는 현재 태양전지, 트랜지스터, 매트릭스 배열 및 이미지 센서 등의 분야에서 이용되고 있다. 자세히 이야기 하면, 여러 가지의 광전효과 물질에 대한 특성이 있으며, 가시광선영역에 대하여 > $10^5cm^{-1}$이상의 매우 높은 광흡수계수와 낮은 온도를 갖는 증착공정 등이 있다. 박막의 밴드갭은 약 1.6~1.8eV로서 태양전지의 흡수층과 passivation층으로 적절하다. 여러 가지 종류의 태양전지 중 비정질 실리콘 박막/결정질 실리콘 기판의 구조로 이루어진 이종접합 태양전지는 저온에서 공정이 가능한 대표적인 것으로서 HIT(Heterojunction with Intrinsic Thin layer)구조로 산요사에 의해 제안된 것이다. 이것은 결정질 실리콘 기판과 도핑된 비정질 실리콘 박막사이에 얇은 진성층 비정질실리콘 박막을 삽입함으로서, 캐리어 전송을 좋게하여 실리콘 기판 표면의 passivation효과를 증대시키는 결과를 가지고 온다. 실험실 규모에서는 약 20%이상의 효율을 보이고 있으며, 모듈에서는 19.5%의 높은 효율을 보이고 있어 실리콘 기판을 이용한 고효율 태양전지로서 각광을 받고 있다. 이러한 이종접합 태양전지의 대부분은 단결정 실리콘을 사용하고 있는데, 점차적으로 다결정 실리콘 기판으로 추세가 바뀌고 있어, 여기에 맞는 표면 passivation 공정 및 분석이 필요하다. 본 발표에서는 다결정 실리콘 기판위에 진성층 비정질 실리콘 박막을 유도결합 플라즈마 화학기상 증착법(ICP-CVD)을 이용하여 제조하여 passivation 효과를 분석한다. 일반적으로 ICP는 CCP(coupled charged plasma)에 비해 약 100배 이상 높은 플라즈마 밀도를 가지고 있으며, 이온 충돌같은 표면으로 작용하는 것들이 기존 방식에 비해서 작다라는 장점이 있다. 먼저, 유리기판을 사용하여 ICP-CVD 챔버내에 이송 한 후 플라즈마 파워, 온도 및 가스비(SiH4/H2)에 따른 진성층 비정질 실리콘 박막을 증착 한 후, 밴드갭, 전도도 및 결합구조 등에 대한 결과를 분석한 후, 최적의 값을 가지고 250um의 두께를 갖는 다결정 실리콘을 기판위에 증착을 한다. 두께(1~20nm)에 따라 표면의 passivation이 되는 정도를 QSSPCD(Quasi steady state Photoconductive Decay)법에 의하여 소수캐리어의 이동거리, 재결합율 및 수명 등에 대한 측정 및 분석을 통하여 다결정 실리콘 기판의 passivation effect를 확인한다. 제시된 데이터를 바탕으로 향후 다결정 HIT셀 제조를 통해 태양전지 효율에 대한 특성을 비교하고자 한다.

• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.404-411
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• 2012

The reliability of solid oxide fuel cells (SOFCs) particularly depends on the high quality of solid oxide electrolytes. The application of thinner electrolytes and multi electrolyte layers requires a more reliable characterization method. Most of the investigations on thin film solid electrolytes have been made for the parallel transport along the interface, which is not however directly related to the fuel cell performance of those electrolytes. In this work an array of ion-blocking metallic Ti/Au microelectrodes with about a $160{\mu}m$ diameter was applied on top of an ultrathin ($1{\mu}m$) yttria-stabilized-zirconia/gadolinium-doped-ceria (YSZ/GDC) heterolayer solid electrolyte in a micro-SOFC prepared by PLD as well as an 8-${\mu}m$ thick YSZ layer by screen printing, to study the transport characteristics in the perpendicular direction relevant for fuel cell operation. While the capacitance variation in the electrode area supported the working principle of the measurement technique, other local variations could be related to the quality of the electrolyte layers and deposited electrode points. While the small electrode size and low temperature measurements increaseed the electrolyte resistances enough for the reliable estimation, the impedance spectra appeared to consist of only a large electrode polarization. Modulus representation distinguished two high frequency responses with resistance magnitude differing by orders of magnitude, which can be ascribed to the gadolinium-doped ceria buffer electrolyte layer with a 200 nm thickness and yttria-stabilized zirconia layer of about $1{\mu}m$. The major impedance response was attributed to the resistance due to electron hole conduction in GDC due to the ion-blocking top electrodes with activation energy of 0.7 eV. The respective conductivity values were obtained by model analysis using empirical Havriliak-Negami elements and by temperature adjustments with respect to the conductivity of the YSZ layers.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.7129-7138
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• 2015

Background: The polycystic ovary syndrome (PCOS), characterized by hyperandrogenism and chronic anovulation, is a common endocrine disorder in women. PCOS, which is associated with polycystic ovaries, hirsutism, obesity and insulin resistance, is a leading cause of female infertility. In this condition there is an imbalance in female sex hormones. All the sequelae symptoms of PCOS gradually lead to cancer in the course of time. It is heterogeneous disorder of unknown etiology so it is essential to find the exact cause. Materials and Methods: In this study both invasive and non-invasive techniques were employed to establish the etiology. Diagnosis was based on Rotterdam criteria (hyperandrogenism, ovulatory dysfunction, PCOM) and multiparameters using buccal samples and dermatoglypic analysis and cytogenetic study for 10 cases and four age and sex matched controls. Results: In clinical analysis we have observed the mean value of total testosterone level was 23.6nmol/L, total hirsutism score was from 12-24, facial acne was found in in 70% patients with 7-12 subcapsular follicular cysts, each measuring 2-8 mm in diameter. In dermatoglypic analysis we observed increases in mean value ($45.9^{\circ}$) of ATD angle when compared with control group and also found increased frequency (38%) of Ulnar loops on both fingers (UU), (18%) whorls on the right finger and Ulnar loop on left finger (WU) and (16%) arches on right and left fingers (AA) were observed in PCOS patients when compared with control subjects. Features which could be applied as markers for PCOS patients are the presence of Ulnar loops in middle and little fingers of right and left hand. The buccal micronucleus cytome assay in exfoliated buccal cells, we found decrease in frequency of micronuclei and significant increases in frequency of karyolysed nuclei in polycystic ovarian syndrome patients. Chromosome aberration analysis revealed a significant increase in frequency of chromosome aberrations (CAs) in PCOS patients when compared with controls. Conclusions: From this present work it can be concluded that non-invasive technique like dermatoglypics analysis and buccal micronucleus cytome assays with exfoliated buccal cell can also be effective biomarkers for PCOS, along with increased CAs in lymphocytes as a sign of genetic instability. There is a hypothesis that micronuclei and chromosomal aberrations could have a predictive value for cancer. From this present work it can be concluded to some extent that non-invasive technique like dermatoglypics and buccal cell analysis can also be effective for diagnosis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.9
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• pp.17-24
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• 2007

In this paper, we propose the sub-cell reuse partitioning among relays as an efficient resource reuse scheme in the relay-based OFDMA systems. If the frequency resource is reused among relays aggressively, we can increase the cell throughput. However, the interferences due to the frequency reuse may cause the fairness decrease due to the SINR degradation especially at the edge of RS sub-cells. In this paper, to make the cell throughput and fairness performance improved at the same time, we propose a sub-cell reuse partitioning scheme that divides a relay sub-cell into inner zone for aggressive reuse and outer zone for sparse reuse. The performance of the proposed scheme has been analyzed by computer simulation. We also applied a scheduling algorithm that can work together with the proposed sub-cell reuse partitioning scheme. Simulation results show that the proposed scheme can improve both the throughput and the fairness performances. In particular, when the scheduling is applied for the improvement of fairness, it is shown that the throughput performance can be enhanced more efficiently by the proposed scheme.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.260-267
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• 2000

Giant cell interstitial pneumonia. a synonym for hard metal pneumoconiosis, is a unique form of pulmonary fibrosis resulting from an exposure to hard metal dust. A case of biopsy-proved giant cell interstitial pneumonia in the absence of appropriate history of exposure to hard metal dust is reported. The patient presented with clinical features of chronic interstitial lung disease or idiopathic pulmonary fibrosis. He worked in a chemical laboratory at a fertilizer plant, where he had been exposed to various chemicals such as benzene and toluene. He denied having any other hobby in his house or job at work, which may have exposed him hard metal dust. High-resolution CT scan revealed multi-lobar distribution of ground glass opacity with peripheral and basal lung predominance. The retrieved fluid of bronchoalveolar lavage contained asbestos fiber and showed neutrotphil predominance. Surgical lung biopsy was performed for a definite diagnosis. Lung specimen showed alveolar infiltration of numerous multinucleated giant cells with mild interstitial fibrosis. Upon detailed examination of the lung tissue, one asbestos body was found. An analysis for mineral contents in lung tissue was performed. Compared with the control specimen, the amount of cobalt and several hard metal components in the lung tissue of this patient was ten times higher. We speculated that the inconsistency between occupational history and the findings of pathologic and mineralogical analyses could be explained by the difference in individual immunologic reactivity to hard metal dust despite the relatively small amount of unrecognized environmental exposure(ED: It's hard to understand what this phrase is trying to say).