건조 담체 고정화 Zymomonas mobilis 세포의 oxidoreductase 활성도

장기효,이제혁,전억한 경희대학교 유전공학연구소 1991 遺傳工學論文集 Vol.3 No.-

박테리아인 Zymomonas mobilis는 glucose와 fructose를 각각 gluconic acid와 sorbitol으로 동시전환할 수 있다. Glucose fructose oxidoreductase에 의하여 glucose의 산화와 fructose의 환원이 일어난다. 균체를 cationic detergent인 CATB(cethyltrimethylammoniumbromide)로 처리하여서 투과성을 높인 후에 glutaraldehyde로 crosslinking 하였던 결과, 균체에서의 glucose-fructose oxidoreduc-tase의 유출이 감소되었으며 고정화균체의 안정성이 증가하였다. 투과성을 증가시킨 균체를 K-carra-geenan으로 고정화하여서 연속공정을 실시한 결과 효소의 안정성이 30일 이상 지속되었다. Kcarrageenan으로 고정화한 균체를 건조시 beads의 견고성과 저장성의 향상이 나타났다. 건조된 Kcarrageenan 담체의 V_(max)값은 39C와 pH6.2에서 free cells의 거의 절반값을 나타내었다. 연속공정에서 회석비율 0.1h^(-1)일때 wet beads와 건조 beads에서의 sorbitol 생산성은 각각 3.2∼3.5, 2.85∼2.9(g/l-h)를 나타내었다. The bacterium Zymumonas mobilis is able to convert glucose and fructose to gluconic acid and sorbitol simultaneously. The enzyme complex, which is responsible for glucose oxidation and fructose reduction, has been described as glucose-fructose oxidoreductase. After treatment of the cells with cationic detergent CTAB(Cetyltrimethylammoniumbromide) for permeabilization, the cells were treated with glutaraldehyde in order to crosslink enzymes. Glutaraldehyde treatment of the permeabilized cells could improve the stability of the system by decreasing the loss of glucose-fructose oxidoreductase. The methods of glutaraldehyde cross-linking of enzymes in CTAB treated cells immobilized in K-carrageenan showed a stable ability of enzymes in CTAB treated cells oxidoreductase for 30 days of process. K-carrageenan beads entrapped with permeabilized cells were dried to improve bead rigidity and storage stability. The value of V_(max) for the dry K-carrageenan beads was found to a 1/2 of that of free cells. It was shown that the productivities of the continuous process with wet K-carrageenan beads and dry beads at dilution rate 0.1h^(-1) were 3.2-3.5 g/l-h and 2.85-2.9 g/l-h, respectively.

새로운 유사 원자층 증착 방법에 의한 산화막의 형성 및 터널링 자기 접합에의 응용

한신희,정원철,이장식,김병동,주승기 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.1

The tunneling barrier is crucial to the overall performance in magnetic tunnel junction. We have suggested a new formation method for the tunnel barrier, which has utilized pseudo atomic layer deposition with sputtering (PALDS). As is well known, all metallic thin films oxidize more or less under atmospheric conditions. With using this property of metallic thin films, we have prepared tunnel barrier by sputtering metallic thin film and exposing it to the oxygen ambience. From transmission electron microscopy (TEM) observation, the formed tunnel barrier has been confirmed to have clear and good interface between magnetic layers and tunnel barrier. From atomic force microscopy (AFM) observation, it has been also confirmed to have low surface roughness. The TMR MRAM cell manufactured using PALDS method has been shown to exhibit typical tunnel resistance of 86 KΩ·μm^2 and TMR ratio of about 40%. The 40% of MR is quite large. It is considered that this value is geometrically enhanced magnetoresistance due to the low junction resistance of MTJ.

스트레인 게이지를 利用한 土壤硬度計의 開發 : Ⅱ. 實用化試驗 Ⅱ. Application Experiment

章益柱,李基明,金泰漢 COLLEGE OF AGRICULTURE KYUNGPOOK NATIONAL UNIVERSI 1984 慶北大農學誌 Vol.2 No.-

The soil hardness tester was developed in order to increase the accuracy of measurement and easiness of handling and make it possible to read the data continuously which might be impossible with conventional soil-hardness tester. A strain gauge and a potentiometer were mounted at cone penetrometer in this soil hardness tester. A series of soil hardness tests were conducted at the laboratory using this measuring system. And the results were compared with those obtained from cone penetrometer which was widly used for this purpose. Also, the soil resistance characteristics were investigated when cone, plate and cone-plate were tested, respectively. The following conclusions were drawn from the results: 1. The soil hardness tester developed in this experiment read data more accurately than cone penetrometer did, which was designed to read with dial gauge. Also, it made possible to read the data continuously as it penetrated from the surface to subsoil. 2. When cone, plate and cone-plate were penetrated into the test soil, soil hardness increased as depth increased gradually. Approximately at a 15㎝ of soil depth, the increase of soil hardness stopped and increased again as it penetrated deeply. This phenomenon seemed to be caused from soil resistance characteristic to penetration. 3. The desirable diameter of the plate seemed to be 50㎜ or more for measuring the surface hardness of the soil sample used in this experiment.

마우스 종양발생에서 Nitric Oxide의 역할에 관한 연구 Ⅲ : Helicobacter pylori에 의해 유발된 마우스 위암에서 염증매개인자의 역할 The role of inducible nitric oxide synthase and cyclooxygenase-2 in H. Pylori-associated gastric carcinogenesis

남기택,오상연,조현무,이국경,강진석,제정환,최미나,한상욱,김대용,장동덕,양기화,안병우 식품의약품안전청 2001 식품의약품안전청 연보 Vol.5 No.-

feficotorfer fyf☞ri(Hp)가 위암파 관련이 있다는 역학적인 증거는 많이 있지만 이에 대한 정확한 기전에 대해선 밝혀져 있지 않고 있으며 실험동물 모델도 적절하지 못한 것으로 알려져있다. 본 실험에서는 위암의 원인으로 알려져 있는 f, fyforf'(Hp)를 이용하여 마우스에서 위암 모델을 확립하고 만성염증과정 중에 생성되는 리0와 COX-2 등의 발현이 위암발생에 미치는 명향을 통하여 예방과 치료를 위한 점근을 시도하고자 하였다. 마우스를 7군으로 나누어서 1, 2, 3, 4군의 등물은 MNU를 증류수에 200ppm 농도로 음수병득 이용하띤 10주간 격주로 투여하였으며 MHU 음술 투여 1주 휴씩 후 배양한 f. fyrofi 를 약 109cru/rfll 로 맞춰 한 마리당 0.1ml 씩 이틀 간격으로 세 번에 걸쳐 하룻방 금식시킨 1, 2, 3, 5, 6, 7군기 마우스의 위장에 투입하떴다. 균 투입을 마친 후 다응 날부터 2군쏙 6군은 iNOS 억제제인 aminoguanidine(AG)을 음수병으로 툰여하였으며 3군과 7군은 COX-2 척제제인 nimesulide(NSD)를 투여하였다. 위의 종양발생양상을 샅최보면 bfNU와 Hp만을 투여한 1 관 ; (hfNU +Hp), 2군 : iNO을 inhibitor 투여군(MNU+HP+AG'1. 3군 ;CO딘-2 Inilibitor 투여군(MNU누Hp누 NSD), 4군 ,MNlf 단독투여군, 5군 ;Hp 단독투여춘, 6군 ; 러p 단독에 AG투여군, 7군 , Hp 단독에 NSD투여군의 종양발샐을은 각각 쁜.Bff(l1/16), 70.6%f12/ti), 했.9ff(7/18), 10%(1/10), Off(O/IS)0%(O/S), 0%(O/5)의 발쟁율을 보여 iNOS 억제제인 AC은 좁양발생을 억계하지 못하였으며, COX-2억제제인 NSD 는 종양발생을 유의적으로 감소시켰다. 콩양발생개수에서는 2.62±0.36, 1.41츠0.14, 0.44 르0.12, 0.10±0.10을 보여 AC와 NSD에서 유의성 있게 발생개수를 줄였다. Hp 단독투여에 의해즌는 종양발생이 나타나지 않았으며 HP+AG, Hp+ IfSD 추여군에콕 시험증료 시점에 약물에 의해 Hp의 제균효과가 있는지의 여부를 확인끓기 위하여 PCR을 이용하여 확인한 결과 모두 양성인 것으로 나타나 Hp의 제균효과에 의한 촐양발생 억제가 일어나지는 않았다. 위의 결과로 볼 때 Hp는 위암발생을 촉진하는 것으로 나타났고 딘p 감염시 매개되는 염증인자를 억제하였을 때 종양발생을 억제하는 것으로 위암 발생에서 염증매개인자는 종양을 촉진하는 것으로 나타났으며 it,705 억제제쓱 COX-』 억제제의 위알 예밭효과fl는 효과적일 것으로 사료된다 In spite of a large volume of epidemiological evidence indicating significant relationship between H. pylori infection and gastric adenocarcinoma, a doubt still exists on an elevated risk of stomach cancer by H. pylori infection due to lack of direct evidence of their exact mechanistic link. It is, therefore, essential to have an appropriate animal model for detailed analysis of the role of H. pylori played in gastric carcinogenesis. There is a wealth of evidence to support that over production of inducible nitric oxide synthase(iNOS) and cyclooxygenase-2(COX-2) is involved in the pathogensis of various cancer in both rodents and humans. The aim of this study was to establish a mouse model for H. pylori-associated gastric carcinogenesis and to identify the role of inducible nitric oxide synthase(iNOS) and cyclooxygenase-2(COX-2) played during the gastric carcinogenesis in mice. Eighty-three specific pathogen free, six-week-old male C57BL/6 mice were randomly divided into seven groups. Animals of the group 1, 2, 3, 4 were given MNU in their drinking water at the concentration of 200 p.p.m. for total five cycles of one-week regimen with one-week pause. After completion of MNU administration, they were given autoclaved distilled water for one weeks, and groups 1, 2, 3, 5, 6, 7 were inoculated with H. pylori. After completion of H. pylori. inoculation, groups 2 and 6 were given aminoguanidine in their drinking water at concentration of 1000p.p.m. and animals of group 3 and 7 were given the diet containing 200 ppm nimesulide at 12 weeks of age. All animals were killed at 50 weeks of age. The incidences of the glandular stomach tumors in the group 1, 2, 3 and 4 were 87.5%(14/16), 76.4%(13/17), 44.4(8/18), 10.0%(1/10), respectively and the tumor incidence of group 3(MNU→Hp+nimesulide) was significantly lower than those of group 1(MNU→Hp) at the value of P<0.01. The average numbers of tumors of group 2(MNU→Hp+AG : 1.41±0.24) and group 3(MNU→Hp+nimesulide : 0.44±0.12) were significantly lower than those of group 1(MNU→Hp : 2.62±0.36) at the value of P<0.05. Therefore, overproduced iNOS and COX-2 plays an important role in mice gastric carcinogenesis. We concluded iNOS and COX-2 inhibitor have good effects on gastric carcinogenesis.

서울대학교치과병원 소아치과를 내원한 교정환자의 분포양상에 대한 연구

구용한,현홍근,김정욱,장기택,이상훈,한세현,김종철 大韓小兒齒科學會 2009 大韓小兒齒科學會誌 Vol.36 No.4

과거에 비해 소아 및 청소년기에 교정치료를 시작하는 경우가 증가하고 있으며 따라서 소아치과에서 교정치료가 차지하는 비율 역시 증가하는 추세이다. 이러한 변화에 맞추어 소아치과에 내원하는 교정환자의 분포 양상을 파악하기 위하여 본 연구를 시행하였다. 2006년 1월부터 2008년 12월까지 서울대학교 치과병원 소아치과를 내원한 환자 중 교정 진단 받은 792명을 대상으로 조사를 진행하였으며 다음과 같은 결과를 얻었다. 1. 교정 진단을 받은 환자의 연령 분포는 8세가 22%로 가장 많았고 7세(19%), 9세(16%) 순서로 나타났다. 2. 골격 분포는 골격성 1급 부정교합이 52%로 가장 많았고 3급(29%), 2급(19%)순서로 나타났으며 연령이 낮은 경우 3급 부정교합 환자의 비율이 높은 경향을 보였다. 3. 총 792명의 환자 중 28%인 218명에서 전치부 반대교합을 보였으며 연령이 낮은 경우 그 비율이 높은 경향을 보였다. Distribution of orthodontic patients in pediatric dental clinics has increased recently. So it is worth to study about the present status of orthodontic patients in pediatric dental clinics. The purpose of this study was to recognize the characteristics and orthodontic patterns of orthodontic patients in pediatric dental clinics. The material consisted of distribution and orthodontic analysis records of 792 new patients in the department of pediatric dentistry, Seoul National University Dental Hospital, from 2006 to 2008. Results were as follows 1. In age distribution, 8-year-olds group comprised 22%, 7-year-olds 19%, 9-year-olds 16%, 10-year olds 15%, 11-year-olds 11%, and other age groups comprised 18%. 2. In skeletal patterns, skeletal class Ⅰ patients comprised 52%, class Ⅱ 29%, and class Ⅲ 19%. 3. In vertical facial types mesofacial comprised 41%, brachyfacial 35%, and dolichofacial 24%. 4. Out of 792 patients 218 patients(28%) showed anterior cross-bite, and the occurrence ratio of anterior cross-bite increased as the age decreased.

純粹굽힘을 받는 3개의 圓孔을 가진 평판의 應力解析에 관한 硏究

崔壯宇,鄭準基,韓秉基 弘益大學校 1982 弘大論叢 Vol.14 No.2

Flat plate specimens with three circular holes were subjected to pure bending. The stress distribution, stress concentration factors, and movement of the isotropic point of these specimens were studied by the photoelastic method and finite element method. Photoelastic method has been a good technique for complete engineering analysis, but the finite element method has developed simutaneously with the increasing use of high speed electronic digital computers and with the growing emphasis on numerical methods for engineering analysis. The Athors try to make comparisons of these two methods.

수직적 안모형태와 치아성숙도의 상관관계에 대한 연구

구용한,현홍근,김정욱,장기택,이상훈,한세현,김종철 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.1

본 연구는 수직적 안모형태와 치아성숙도의 관계를 평가하고 이러한 연관성에 대한 사춘기 성장의 영향을 평가하기 위한 것이다. 이번 연구를 위해 7세에서 9세, 13세에서 15세 환자 1306명을 Ricketts의 VERT index를 이용하여 수직적 안모 형태를 분류하였고 환자들의 치령을 Demirjian법으로 평가하여 다음과 같은 결과를 얻었다. 1. 모든 군에서 치령이 역령과 비교 시 통계적으로 유의한 수준에서 크게 측정되었다. 2. 사춘기 연령군에서 brachyfacial type의 경우가 dolichofacial type 보다 치아성숙도가 크게 나타나는 경향을 보였다. 여성의 경우는 통계적으로 유의성있게 차이가 나타났으며, 남성의 경우는 통계적 유의성은 보이지 않았다. 3. Brachyfacial type의 경우 사춘기전 군들과 비교 시 사춘기 군들에서 치아성숙도가 유의성있게 높게 나타났으며, dolichofacial type의 경우는 연령층간 치아성숙도의 차이를 보이지 않았다. The purpose of this investigation was to study the relationship between vertical facial pattern and dental maturation in children in pubertal and pre-pubertal periods. The material consisted of lateral head films and panoramic radiographs of 1306 patients. The subjects were selected according to Ricketts's VERT index and other including criteria. These subjects were divided by VERT index to brachyfacial group and dolichofacial group. In each selected subject, dental age was determined according to Demirjian's dental maturity score. All subjects were distributed according to age, vertical facial type and sex, mean and standard deviation of chronological age, dental age and age difference were determined in each group. And the data were analysed to find the difference of tooth maturation by facial pattern. Findings of this study include: 1. In all groups, dental age was determined higher than chronological age in statistically significant level. 2. Compared by vertical facial pattern, in pubertal age groups, it seems that subjects with brachyfacial type presented the tendency to have an advanced dental maturation, only in female group. 3. Compared by pubertal period, brachyfacial groups presented more advanced dental maturation in pubertal groups than pre-pubertal groups.

회전자형 위치센서를 갖는 스위치드 릴럭턴스 전동기의 속도 제어

김한성,장도현,최기원,김홍성 건국대학교 산업기술연구원 1996 건국기술연구논문지 Vol.21 No.-

This paper describes the practical implementation of switched reluctance motor drive for a wide range of operation speeds. Turn-on/off angle of phase switches and magnitude of current depend upon the speed and load variations. The angle controller is designed with one-chip microprocessor 8051 for various real time applications. Turn-on/off angle is controlled by timer/counter mode 2 of 8051. Position sensor for SRM drive consists of the rotor shaped slot-disc and opto-interrupter. Algorithm to control the speed of SRM with rotor type position sensor and to maintain the speed under the changed load is proposed. Experiments are executed to verify the proposed algorithm.

CAM을 이용한 다지 분기 구조의 설계

조현묵,한일국,기장근 公州大學校工科大學生産技術硏究所 1996 論文集 Vol.5 No.-

In this thesis, Multi-way branch structure is designed to execute multiway branch instruction in the wireless LAN protocol processor. Because this structure substitute CAM(Content Addressable Memory) for target selection unit with label index information of program which branch in multiway according to system variables consist of flags & vectors. The CAM store a set of arbitrary variable conditions. Thus, this structure have feature which assign system value for multiway branch, can programming and reconfigure a set of variable conditions. The Desing of Multiway branch structure used cmn8a library which is 0.8um process of Compass tool, have about 9,500 gates and suitable for basis clock 80MHz of wireless LAN protocol processor.

Ferric sulfate를 이용한 유치치수절단술의 3년 후 임상평가

윤연희,장기택,한세현 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.1

15.5% ferric sulfate solution을 이용하여 유치치수절단술을 시행한 유구치의 상태를 임상적, 방사선학적으로 평가를 하여 이를 20%로 희석한 formocresol로 치수절단술을 시행한 경우와 비교하였다. 1997년부터 1998년까지 서울대학교병원 소아치과에서 치료를 받은 건강한 환아를 대상으로 하였고, ferric sulfate를 이용한 치수절단술을 치료받은 30개의 치아와 20%로 희석한 formocresol로 치수절단술치료한 23개의 치아, 총 53개의 치아를 평균 34개월 후 follow-up하여 그 임상적, 방사선학적 상태를 조사하였다. ferric sulfate군의 전체적인 성공률은 80.0%이었고, formocresol군의 성공률은 81.0%이었다. 두 군의 결과 차이를 카이제곱검정의 통계방법으로 분석하였다. ferric sulfate군의 4개의 formocresol군의 4개의 차이가 외흡수를 보였고 근단부 치조골파괴는 ferric sulfate군의 3개와 formocresol군의 2개에서 보였다. ferric sulfate군과 formocresol군 사이의 성공률은 통계학적으로 유의한 차이를 보이지 않았다. The objective of this report is to assess clinically and radiographically the state of the primary molars pulpotomized with a 15.5% ferric sulfate solution. The subjects selected were healthy children treated at the pediatric dental clinic of the Seoul National University Hospital in Korea. Thirty teeth were pulpotomized with a ferric sulfate solution(FS). Another twenty-one teeth were pulpotomized with 20% dilute formocresol(FC). Clinical and radiographic data for the fifty-one primary molars were collected with a mean follow-up period of 34 months. The success rate for the FS group was 80.0%. The success rate for the FC group was 81.0%. The differences in the results between the two groups were analyzed statistically utilizing the chi square test. External root resorption was observed in four teeth of FS group and four of the FC group. Periapical bone destruction was observed in three of FS group and two of FC group. There were no significant statistical differences between the success rates for FS group and the FC group.