어린이 교통사고 중 사망 및 중상사고와 같은 대형 사고를 줄이기 위해서는 차량이 어린이 보호구역을 일정속도 이하로 주행하도록 제한하는 것이 가장 중요하며, 그 때문에 어린이 보호구역 내에서의 제한속도는 현재 30km/h로 규정되어 있다. 하지만 어린이 보호 구역을 통과하는 차량들의 주행특성을 살펴보면 대부분의 차량들이 제한속도 이상의 속력으로 주행하고 있는 것으로 나타났다. 이는 어린이 보호구역 설치 및 운영의 근본 취지에 반하는 것으로 어린이 보호구역이 근본 목적을 달성하지 못하고 있는 것으로 평가할 수 있다. 본 연구에서는 서울시의 8개 초등학교를 대상으로 어린이 보호구역 내 시설물 조사와 속도조사를 통해 어린이 보호구역을 통과하는 차량들의 제한속도 준수여부를 파악하여 제한속도 위반에 영향을 미치는 요인을 규명하였다. 분석결과 조사시간, 차로수, 보도폭, 도로의 유색포장 상태가 유의수준인 95% 수준에서 속도위반에 영향을 미치는 유의한 변수로 나타났다. 본 연구를 통하여 향후 어린이 보호구역 내에서의 어린이 안전성을 더욱 향상시킬 수 있을 것으로 기대된다.

Composites of gadolinium-doped ceria/magnesia(CGO/MgO) were synthesized and characterized for the electrolytes of intermediate temperature solid oxide fuel cells. XRD and SEM results revealed that composite electrolytes consisted of their own phases after sintering at 1400˚C without noticeable solid solution of Mg into CGO. As the MgO content increased, the total electrical conductivity decreased, which might be attributed to the decrease of grain boundary conductivity, possibly due to the lowering of the continuity of the CGO grains and blocking effects of the insulating MgO phase. The space charge effect may not be a significant factor to affect the electrical conductivity of the CGO/MgO composites.

Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters, the system L amino acid transporters are the major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed in cancer cells to support their continuous growth and proliferation. 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid(BCH) is a model compound for study of amino acid transporter as a system L selective inhibitor. We have examined the effect and mechanism of BCH on cell growth suppression in FaDu human head and neck squamous cell carcinoma. The BCH inhibited the L-leucine transport in a concentration-dependent manner with a IC 50 value of 43.8±4.3μM. The majority of L-leucine uptake is, therefore, mediated by LAT1 in FaDu cells. The growth of FaDu cells was inhibited by BCH in the time- and concentration- dependent manners. The formation of DNA ladder was not observed with BCH treatment in the cells. Furthermore, the proteolytic processing of caspase-3 and caspase-7 in the cells was not detected by BCH treatment. These results suggest that the BCH inhibits the growth of FaDu human head and neck squamous cell carcinoma through the intracellular depletion of neutral amino acids for cell growth without apoptotic processing

In this study, I attempted to the architectural design characteristics of Daeung-Jeon in Sudeok Temple. For this purpose, After I set up several assumptions in the basis of the general characteristics of Korean wood architecture, and then, analyzed floor plan, structural formation and section sizes of structure and bracket members in relation to module and unit. As the results, the characteristics of the design process of plan and structure are follows. (1) 1 ja(尺), the unit applied to this building is measured $307.6{\sim}318.3mm$) and the average is 312.9mm (2) It is estimated that the floor plan designed on the basis of the top of columns. By the applied unit, every bay of the front side and the side is each designed by 15 ja and 8.5 ja. (3) The section is composed of piled members which have same section size. As basic module of section size called 'jae(재;材)', it is estimated at width 0.45 ja by height 0.75 ja. And as the secondary module, height between jae and is called 'gyoe(계;)' and it wes designed by three height size of 0.25 ja, 0.27 ja and 0.30 ja, (4) It is estimated that the section plan was designed by the order as follows. Firstly, the horizontal position of purlins wes decided on the basis of the intersection point of long and short rafters, and then the position and the section size of purlins and jangheyo(長舌) wes decided on the basis of the slope of roof and rafters. Secondly, going down from purlins, the members of structure composed of 'jae' and 'gyoe' was repeated. Lastly, for the purpose of linking the structure members located on the center line of adjacent purlins organically, the height of whaban(화반) was controlled.

Dentin is a mineralized tissue formed by odontoblasts that are differentiated from ectomesenchymal cells , The molecul ar mech anism of odontoblast diffe rentiation remains unclear, Amino acid transporters play an important role in s up plying nutri tion to normal a nd ca ncer cells including odntoblasts, and for cell proliferation , Amino acid transport system L is a maj or nutrient t ransport system responsible for the Na+' -independent transport o[ neutral amino acids incJuding several essentiaJ amino acids , The system L is divided into two major subgroups, the L-type amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2) , In this study, the expression pattern and role of amino acid transport system L were, therefore, investigated in the differentiation of MDPC-23 cells derived from mouse dental papilla celJs , To determi ne the expression Jevel o[ amino acid transport system L participating in intracelJ ular transport of amino acids in the differentiat ion 0 1' MDPC-23 cells, it was examined by RT-PCR, observation of cell morphoJogy‘ A1izaline red-S staining ancl uptake analysis after inclucing experimental differentiation in MDPC-23 cells The res ults were as follows , The LAT1 mRNA was expressed in the early stage of MDPC-23 cell differentiation , The expression leveJ was gradually increased by time course and it was decreased after the late stage, The LAT2 mRNA was not observed in the earJy stage of MDPC-23 cell differentiation, The LAT2 mRNA was expressed at the 11 days 0 1' MDPC-23 cell differentiation and the expression level was gradually decreased by time course, There was no changes in the expression level of 4F2hc mRNA, the cofactor of LAT1 and LAT2, during the differentiation of MDPC-23 cells , The expression of ON mRNA was graduaJJy decreased but the expression of ALP mRNA was increased during differentiation of MDPC-23 cells , The L-Ieucine uptake was increased by time cour se from the early stage to the 9 days in MDPC-23 cell differentiation , The amount of L-Ieucine uptake was maintained to the 11 and 14 days of MDPC-23 cell differentiation As the resul ts‘ it is considered that among neutral amino acid transport system L in differentiation of MDPC-23 cells , the LATl has a key role in cell proliferation in the early stage and middle stage of cell differentiation and the LAT2 has an important roJe in ceJJ differenti ation and mineralization in the Jate stage of cell differentiation for providing cells with neutral a mino acids incJuding several essentiaJ amino acids

System L amino acid transporter is a major route for providing living cells with neutral amino acids including several essential amino acids. To elucidate the expression pattern of L-type amino acid transporter 1 (LAT1) in the bone formation process, the expressions of LAT1 and its subunit 4F2 heavy chain (4F2hc) were investigated in the healing process after the implantation of bone graft materials in the calvarial osseous defected rats. Circular calvarial defects (1 cm in diameter) were made midparietally. The rats were divided into 4 groups of 1 control group and 3 experimental groups. In the control group, the defect was only covered with soft tissue flap. In the experimental groups, they were filled with human particulate dentin (particulate dentin group), with plaster of Paris (plaster of Paris group) and with the mixture of human particulate dentin and plaster of Paris with ratio of 2 : 1 by weight (mixture group). The rats were sacrificed at the 1, 2, 4 and 8 weeks after operation and the RT-PCR analysis and immunohistochemical analysis were performed. In the RT-PCR analysis, the mRNAs of LAT1 and 4F2hc were strongly detected in all 4 groups. In the immunohistochemical analysis, at 1 week after operation, the LAT1 protein and its subunit 4F2hc protein were mainly expressed in the osteoblasts, osteocytes and interstitial tissues of the around the defect and inner part of newly forming bone in all 4 groups. The expressions of LAT1 and 4F2hc proteins were decreased at 2 and 4 weeks after operation. The LAT1 and 4F2hc proteins were scarcely expressed at 8 weeks after operation in all 4 groups. These results suggest that the LAT1 and its subunit 4F2hc highly expressed at the early stage of new bone formation and may have an important role in providing cells with neutral amino acids including several essential amino acids at that stage.

Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters, the system L amino acid transporters are the major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter 1 (LAT1) is over-expressed to support cell growth in malignant tumors. The double stranded RNA-mediated RNA interference (RNAi) analysis can be in a wide variety of eukaryotes to induce the sequence-specific inhibition of gene expression. In this study, we examined the effect of LAT1 short interfering RNA (siRNA) on cell growth using siRNA of LAT1 in the KB human oral squamous cell carcinoma. In the RT-PCR analysis and western blot analysis, the siRNA of LAT1 inhibited expressions of LAT1 mRNA and protein. The uptake of [14C]L-leucine was inhibited by siRNA of LAT1. In the MTT assay, the siRNA of LAT1 inhibited the growth of the KB cells in the time-dependent manner, indicating that the growth inhibition of KB cell by the siRNA of LAT1 is induced by the blocking of neutral amino acid transport mediated by LAT1. These results suggest that the transport of neutral amino acids including several essential amino acids into the KB human oral squamous cell carcinoma is mediated mainly by LAT1. Further, the LAT1 would be a new target for the inhibition of cancer cell growth.

Amino acids a re required fo1' protein synthesis and energy sources in all living cell s. System L amino acid trans porters neutral amino aci cls i n a Na +' - independent manner. In ma 1ignan t tumors the L-type amino acid t ranspor te r 1(LA1'1), the first isoform 0 1' system L. is highly expressed to suppor t tumo1' cell growth. ln the present study, the expression 0 1' the system L amino acid transporter and BCH cytotoxicity were examined and compa red in both rat gli a l and C6 g lioma cel ls 1'he rat glia l cells expressed the L-type arnino acid t ra nsporter 2(LA1'2). the second isoform 이 system L, with its subu ni t 4F2hc. whereas the LA1'1 was not expressed. 1'he C6 glioma cells expressed LA1'1 with 4F2hc but not LA1'2 1'he [14C]L-leucine uptakes by the glial and C6 glioma cells were inhibi ted by BCH in a co ncent ration-d e pendant man ner wi th the lC50 values of 270.0 :t 13.7 μ M and 73.1 :t 4.5 μ M, respectively. 1'he cell g rowth was inh ibi ted by BCH in the time, concen tration-dependant manner in the gli al and C6 glioma cell s . 1'he rate of cell growth inhi bit ion induced by BCH in the C6 glioma cells was hi gh er than that in the gli al cells 1'hese results s uggesL that the tra ns ports of neutra l amino acids inc1uding several essenti al amino acids into rat g lial and C6 glioma cel ls a re for the most part mediated by LA1'2 and LA1'1, respectively. Therefore‘ the rat glia1 and C6 gJioma cells are excell ent tools for examing the proper ties of LA1'2 and LA1'1, respectively. Moreover, the spec너 i c inh ibi tion 0 1' LATl in cancel cells might be a new rationa le f'or anti -cancer therapy

Amino acid transporters play an important role in supplying organic nutrient to cells. The expression of L-type arnino acid transporter 1 (LATl) and its subunit 4F2 heavy chain (4F2hc) was evaluated to deterrnine the alterations to these transporters in oral norrnal mucosa (ONM) , oral precancerous lesion (OPL) and oral squamous cell carcinoma (OSCC). Sections from formalin-ftxed, paraffm-embedded S따nples of ONM, OPL or OSCC were exarnined using immunohistochernical staining to detect LATl and 4F2hc proteins. 까le LATl and 4F강lC expression increased progressively from ONM to hypeφ，Iastic and to dysplastic lesions and OSCC. In partiαlar， LATl rnay be a more S야dftc indicator of tumor prog~않sion than 4F2hc. 까le gradually increasing LA Tl and 4F2hc expression detected during the multistep progressive change shows that the protein rnay have an important role in the early stages of multistep oral carcinogenesis. In addition, the specific inhibition of LA Tl and 4F2hc rnight be a new rationale to suppress oral cancer progression.

Nitric oxide (NO) plays a key role in the processes of inflammation and carcinogenesis. Three isoforms of NO 야mthase have been identified: endothelial 띠띠c oxide 와nth앓e (NOS), neuronal NOS, and inducible NOS (이OS). The purpose of this study was to investigate the characteristics of iNOS expression in 7, 12-dimethylbenz[alanthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Sixty three outbred young (6-week-old) male Syrian golden hamsters were randomly divided into three groups: DMBA treated group (n=57) and non-treated (n=3), and mineral-oil treated group (n=3). No iNOS activity could be detected in the untreated or mineral oil-treated pouches. 80th cytoplasmic and nuclear stainings were observed in the DMBA-treated pouch kera띠lCX까es. There were iNOS expression 외so in the strorna1 cells. The mean values of iNOS expression in the epithelium increased gradually from control to dysplastic lesions and more to invasive squ따nous cell carcinoma. πle clifference between iNOS expr'않sion in the normal and that the dysplastic and carcinomatous lesions is statistically significant. The mean values of iNOS expression in the stroma increased gradually from control to dysplastic lesions and more to invasive squamous cell carcinoma. The difference between iNOS expression in the normal and that the carcinomatous lesions is statistica11y si맑， ificant. In conclusion, this study has demonstrated that iNOS is expressed in DMBA-induced hamster pouch carcinomas. πlis finding suggests that iNOS expression may be associated with the development of chemically induced oral carcmomas.

Arrùno acid transpoπers play an important role in supplying nutrition to cells and for cell proliferation. System L is a major nutrient transport system responsible for the Na+-independent transport of large neutral amino acids including several essential amino acids. In malignant tumors, a system L transporter L-type amino acid transporter 1 (LATl) is upregulated to support tumor cell growth. In the present study, we have examined the expression and function of system L amino acid transporter in FaDu human pharyngeal squamous carcinoma cells. RT-PCR, real-time quantitative RT-PCR and westem blot analysis have revealed that the FaDu cells express LATl together with its associaω19 protem 4F2hc, whereas the FaDu cells do not express the other system L isoform L-type amino acid transporter 2 (LAT2). 까le uptake of L-(14Clleucine by FaDu cells is Na+-independent and almost completely inhibited by system L selective inhibitor 2-aminobicyclo-(2,2,1)-heptane-2- carboxylic acid (BCH). The profiles of the inhibition of L-[I4Cllellcine uptake by variolls amino acids in the FaDu cells are comparable with those for the LA T1 expressed in Xenopus 。()(찌es. π1e majority of L-[I4Clleucine uptake is, therefore, mediated by LAT1 in the FaDu cells. These results suggest that the transport of neutral amino acids including several essential amino acids in the FaDu human pharyngeal squamous carcinoma cells mediated by LAT1. In addition, specific inhibition of LAT1 by such agents as BCH in pharyngeal squamous cell carcinomas will be a new rationale for anti-cancer therapy.

Odontogenic keratocysts(OKCs) are frequently associated with erupted or impacted tooth. In such instances, the radiographic features simulate those of a dentigerous cyst. The purpose of this study was to evaluate a comparative immunohistochemical expression of Ki-67 as a proliferative marker and apoptotic signals in the OKC associated with or without impacted tooth. In addition, we have also been investigated with regard to the proliferative activity and apoptosis comparing the unilocular and multilocular varieties of the OKC. The material for this study consisted of thirty-two cases of OKCs (OKC with impacted tooth, n=16；OKC without impacted tooth, n=16) and ten cases of dentigerous cysts as a comparison. The results revealed that the proliferative activity and apoptosis of OKCs with impacted tooth was higher than those of dentigerous cysts. However, there was no correlation between Ki-67 immunoreactivity or apoptosis and association with or without impacted tooth in 32 cases of OKCs. In addition, this present study showed that there was no correlation between the unilocular and multilocular varieties of the OKCs in proliferative activity and apoptosis.

It has been said that amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. System L is a major nutrient transport system responsible for the Na+-independent transport of large neutral amino acids including several essential amino acids. In malignant tumors, a system L transporter L-type amino acid transporter 1(LAT1) is up-regulated to support tumor cell growth. In the present study, we have examined the function of LAT1 and its expression in the KB human oral epidermoid carcinoma cells. RT-PCR, western blot analysis and immunohistochemical analysis have revealed that KB cells express LAT1 in the plasma membrane together with its associating protein 4F2hc, whereas KB cells do not express the other system L isoform LAT2. The uptake of L-[14C]leucine by KB cells is Na+-independent and almost completely inhibited by system L selective inhibitor BCH. The profiles of the inhibition of L-[14C]leucine uptake by amino acids in the KB cells are comparable with those for the LAT1 expressed in Xenopus oocytes. The majority of L-[14C]leucine uptake is, therefore, mediated by LAT1 in the KB cells. These results suggest that the uptakes of neutral amino acids including several essential amino acids in the KB oral epidermoid carcinoma cells mediated by LAT1. In addition, specific inhibition of LAT1 by such agents as BCH in human oral squamous cell carcinomas will be a new rationale for anti-cancer therapy.

질화규소로 코팅된 질화규소-질화붕소 이층 층상복합재료의 접촉하중에 의한 파괴거동을 고찰하였다. 그 결과 코팅층내에서 새로운 종류의 균열들이 발견되었고, 이러한 균열들은 기하학적으로 원추 모양을 가짐을 확인하였다. 외부에서 가한 하중의 에너지는 코팅층 뿐 아니라 damage를 흡수할 수 있는 기판층 내로 분산되어 코팅층에서 시작된 균열들의 전파가 억제되었다.