불포화 레시틴을 이용한 나노리포좀 개발에 관한 연구

강기춘,이청희,왕수환,이천일,표형배,정노희 한국공업화학회 2004 응용화학 Vol.8 No.1

Nowadays many products using nano-technology have been released and nano-technology would be more prospected in all kinds of industries especially cosmetic manufacturing and ingredient fields. In cosmetics, the saturated lecithin, one of the main surfactants to make liposome, has been used for its stability but it has been substituting by unsaturated lecithin which has excellent skin affinity and penetration. So we studied to develop nano-liposome below 50㎚ with unsaturated lecithin. To make stable nano-liposome, many factors including solvent like propylene glycol, pH balance, homogenizing pressure and liposome stabilizer like surfactant are important especially stearate series surfactants have positive effect in liposome size and long term stability. But in liposome with saturated lecithin, surfactant has negative effect and appropriate amount of oil should be used to be stable. So we could conclude that unsaturated lecithin is suitable than saturated lecithin to make nano-liposome.

해수의 담수화 시스템 및 생산수의 수질 특성

康鍾洙,金忠煥 嶺南大學校 環境問題硏究所 1999 環境硏究 Vol.18 No.2

Flowable 및 microfill 복합레진으로 충전된 제 5급와동에서 load cycling 전,후의 미세변연누출 비교

강석호,김오영,오명환,조병훈,엄정문,권혁춘,손호현 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.2

Low-viscosity composite resins may produce better sealed margins than stiffer compositions (KempScholte and Davidson, 1988; Crim, 1989). Flowable composites have been recommended for use in Class V cavities but it is also controversial because of its high rates of shrinkage. On the other hand, in the study comparing elastic moduli and leakage, the microfil had the least leakage (Rundle et al. 1997). Furthermore, in the 1996 survey of the Reality Editorial Team, microfills were the clear choice for abfraction lesions. The purpose of this study was to evaluate the microleakage of 6 composite resins (2 hybrids, 2 microfills, and 2 flowable composites) with and without load cycling. Notch-shaped Class V cavities were prepared on buccal surface of 180 extracted human upper premolars on cementum margin. The teeth were randomly divided into non-load cycling group (group 1) and load cycling group(group 2) of 90 teeth each. The experimental teeth of each group were randomly divided into 6 subgroups of 15 samples. All preparations were etched, and Single bond was applied. Preparations were restored with the following materials (n=15) : hybrid composite resin [Z250(3M Dental Products Inc. St.Paul, USA), Denfil(Vericom, Ahnyang, Korea)], microfil [Heliomolar RO(Vivadent, Schaan, Liechtenstein), Micronew(Bisco Inc. Schaumburg, IL, USA)], and flowable composite[AeliteFlo(Bisco Inc. Schaumburg, IL, USA), Revolution(Kerr Corp. Orange, CA, USA)]. Teeth of group 2 were subjected to occlusal load (100N for 50,000 cycles) using chewing simulator(MTS 858 Mini Bionix Ⅱ system, MTS Systems Corp., Minn, USA). All samples were coated with nail polish 1mm short of the restoration, placed in 2% methylene blue for 24 hours, and sectioned with a diamond wheel. Enamel and dentin/cementum margins were analyzed for microleakage on a sclale of 0 (no leakage) to 3 (3/3 of wall). Results were statistically analyzed by Kruskal-Wallis One way analysis, Mann-Whitney U-test, and Student-Newmann-Keuls method. (p=0.05) Results: 1. There was significantly less microleage in enamel margins than dentinal margins of all groups. (p<0.05) 2. There was no significant difference between six composite resin in enamel margin of group 1. 3. In dentin margin of group 1, flowable composite had more microleakage than others but not of significant differences. 4. There was no significant difference between six composite resin in enamel margin of group 2. 5. In dentin margin of group 2, the microleakage were R>A=H=M>D>Z. But there was no significant differences. 6. In enamel margins, load cycling did not affect the marginal microleakage in significant degree. 7. In dentin margins, load cycling did affect the marginal microleakage only in Revolution. (p<0.05)

세라믹 브라켓의 제거 시 Er : YAG 레이저의 효능

서충환,장나영,채종문,조진형,김상철,강경화 대한치과교정학회 2009 대한치과교정학회지 Vol.39 No.4

본 연구에서는 세라믹 브라켓 제거에 Er:YAG 레이저 조사가 도움이 되는지 알아보고, 브라켓 제거에 적합한 레이저 조사 방법을 연구하였으며, 또 이렇게 적용된 레이저가 치수와 법랑질에 손상을 주는지도 알아보았다. 총 190개의 치아, 단결정 세라믹 브라켓(MISO), 다결정 세라믹 브라켓(Transcend series 6000)과 KEY Laser3를 사용하였다. 실험군은 세라믹 브라켓의 종류(단결정, 다결정)와 레이저의 에너지(140, 300, 450, 600 mJ)에 따라 분류하였으며, 레이저를 브라켓당 두 곳에 1펄스씩 조사하고, 전단 강도를 측정하였다. 대조군은 레이저를 조사하지 않는 군으로 하였다. 레이저 조사에 의한 열 효과는 브라켓 하방 법랑질과 치수강에서 측정하였으며, 전단 강도 측정 후 치면에 남아있는 접착제의 양을 접착제 잔류 지수(adhesive remnant index)를 이용하여 평가하였다. 레이저 조사로 인한 접착제의 파괴 양상과 법랑질 표면 변화를 주사전자현미경으로 관찰하였다. 모든 세라믹 브라켓군에서 레이저 에너지가 증가 할수록 전단 강도는 유의하게 감소하였다. 또한, 브라켓 하방 법랑질에서 최대 온도 변화는 평균 3.78˚C 상승에 그쳤으며, 치수강에서 최대 온도 변화는 평균 0.9˚C 상승에 그쳤다. 주사전자현미경을 이용한 법랑질과 접착제 단면 관찰에서 접착제 표면이 레이저에 의해 붕괴되어 분화구 모양의 구덩이로 관찰되었으며, 일부 시편에서 약 10 - 30μm의 법랑질 손상이 발견되었다. Transbond XT로 부착된 단결정 도재 브라켓(MISO)의 디본딩에 Er:YAG 레이저를 이용할 경우, 300 - 450 mJ의 레이저 에너지를, 그리고 다결정 도재 브라켓(Transcend series 6000)의 경우는 450 mJ 정도의 에너지를 사용하는 것이 효과적이고 안전할 것으로 생각된다. Objective: The aim of this study was to find out whether Er:YAG laser can aid in debonding ceramic brackets, and to see what kind of method will be the most appropriate for debonding. Methods: One hundred and ninety teeth, monocrystalline brackets (MISO, HT, Ansan-Si, Korea), polycrystalline brackets (TranscendTM series 6000, 3M Untek, Monrovia, CA, USA) and the KEY Laser3 (KavoDental, Biberach, Germany) were used. Experimental groups were classified according to the type of ceramic brackets, and the amount of laser energy (0, 140, 300, 450, 600 mJ). After applying laser on the bracket at two points at 1 pulse each, the shear bond strength was measured. The effect of heat caused by laser was measured at the enamel beneath the bracket and pulp chamber. After measuring the shear bond strength, adhesive residue was evaluated and enamel surface was investigated using SEM. Results: All ceramic bracket groups showed a significant decrease in shear bond strength as the laser energy increased. The greatest average temperature change was 3.78˚C on the enamel beneath the bracket and 0.9˚C on the pulp chamber. Through SEM, crater shape holes caused by the laser was seen on the enamel and adhesive surfaces. Conclusions: If laser is applied on ceramic brackets for debonding, 300 - 450 mJ of laser energy will be safe and efficient for monocrystalline brackets (MISO), and about 450 mJ for polycrystalline brackets (Transcend series 6000).

기질성 뇌장애 환자의 구조적 뇌영상과 비교한 저해상 전자기 단층 촬영 영상

이승환,권구형,박영민,김 현,이강준,정영조 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.3

Objectives : Patients with organic brain lesion can produce unique slow waves (delta and theta) in the EEG. Basic assumption of this study was that the low resolution electro magnetic tomography (LORETA), an inverse source localization program, can provide functional images representing increased slow wave activity in these patients compared to normal subjects. Methods : The current study was performed by 18 channels digital EEG for 10 patients whose organic deficit have been Visually confirmed by CT or MRI. The source images of slow wave (1-7 Hz) frequency were produced by LORETA-key program. Results : We found that in eight out of ten subjects, LORETA successfully found out the source regions which were very closely matched to their original brain lesions. However in two subjects whose organic brain lesions were too small (<1cm) and located out of gray matter, we failed to find any increased slow wave activity compared with normal control. Conclusion : We can conclude that LORETA could be a useful method to provide functional imaging in patients with gray matter deficits in their brain. Its usefulness and limitations were discussed.

3㎛ CMOS 표준셀의 설계

김성환,정강민 成均館大學校 科學技術硏究所 1989 論文集 Vol.40 No.1

Recently, the importance of custom I.C. that is a kind of ASIC(Application Specific Integrated Circuit) is being increased. The standard cell is en effective way for the custom I.C. design. We have designed the standard cell using 3㎛ CMOS(Complementary metal-oxide-silicon) technology. The design objective is to minimize the product of propagation delay term and chip area term, which is used to decide transistor width. To decide transistor width related to propagation delay we have introduced a mathematical model. For 3㎛ CMOS standard cell, the cell height was uniformly chosen to be 102㎛ while minimizing the product of propagation delay term and chip area term. With 3㎛ design rules the channel widths in p-channel and n-channel transistors were designed to be 21㎛ and 10.5㎛, respectively. We investigated the delays of INV(inverter), NR2(2-input NOR) and ND2(2-input NAND) in terms of the fanout numbers using PSPICE program.

벼 생육중기 및 출수기 태풍 "올가" 건풍에 의한 엽신 피해의 품종간 차이와 수량 및 품질 변화

윤영환,김정곤,정남진,곽강수,강양순 한국국제농업개발학회 2003 韓國國際農業開發學會誌 Vol.15 No.4

1999년 8월3일~8월4일간 태풍 올가 도래시 건풍에 의한 생육중기 엽신 피해의 품종간 차이와 출수기 이삭 갈변에 따른 수량 및 품질에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1. 잎의 증산량 및 수분저하속도가 클수록, 잎이 길이가 길고 폭이 넓을수록 엽신의 피해정도가 컸다. 2. 이삭의 피해 정도가 증가될수록 임실 및 등숙비율은 현저히 낮아지는 경향이며, 쌀 수량은 무피해 대비 피해 3~5는 14~16%, 피해 7은 28%, 피해 9는 48% 감수하였다. 3. 이삭의 피해 정도별 백미 완전미 비율은 피해 정도가 클수록 감소를 보였으며 피해 0~3에서 63~65%, 피해 5~9에서 42~58%의 분포를 보였다. 4. 이삭의 피해정도가 증가할수록 백도 및 색도치가 낮아지며, 단백질 함량은 증가하고 식미치는 저하하는 경향을 보였다. This study was carried out to characterize the influence of dry wind by typhoon "Olga" during Aug. 3~Aug. 4, 1999 on the rice plant(Oryza sativa L.). For the purpose, the affection of the dry wind during the mid-growing stage and heading stage on the leaf damage, yield and rice quality were investigated. The extent of the leaf damage increased with the increase of leaf size and transpiration rate, and also with the decrease of moisture content in the leaves. The percentage of fertile grain decreased in proportion to the increase of the extent of the panicle damage. Compared with none-damaged rice plants in the panicle, the milled rice yield decreased by 14~16% in the degree 3~5 of the panicle damage, and 28~48% in the degree 7~9. The percentage of head rice was the same in the both milled and brown rice in the degree 0~3 of the panicle damage. Above the degree 5, however, it decreased with the increase of the panicle damage. The whiteness and lightness decreased in proportion to the increase of the degree in the unhulled, brown and milled rice. And, there was a tendency that the protein content in the milled rice increased but eating quality decreased with the increase of the panicle damage.

현미 온도 조질 후 정백 특성

한충수,김유호,강태환,조성찬 한국산업식품공학회 2003 산업 식품공학 Vol.7 No.1

겨울철 곡온이 낮은 현미는 조직이 단단해져서 정맥시간이 길어지고, 과부하로 인해 도정효율 저하와 소비전력량이 증가한다. 조질은 곡물의 함수율과 곡온을 조절하는 기술로써, 현미의 단단한 조도정수율 및 도정효율을 향상시킬 수 있다. 본 연구에서는 저온 현미 정백시 도정효율 향상 및 품질유지를 위해 적정 현미 조질온도와 정백 후 백도, 강도, 동할미율, 싸라기율, 곡온 상승, 함수율 변화, 소비전력량 등과의 관계를 규명하였다. 현미 조질 곡은 0, 3, 5, 12, 20℃에 대한 정백후 백미 백도 변화는 큰 차이가 없는 것으로 나타났고, 동할미율, 완전립과 동할립 강도 및 싸라기율은 현미 조질 곡온이 높을수록 감소하는 것으로 나타났다. 조질 곡은 12, 20℃인 경우가 정백 후 적정 곡온 상승 규정범위 15℃ 내에 해당되었다. 정백 후 함수율 변화는 조질곡온에 관계없이 외기온도와 정백 후 곡온 차이로 발생한 결로에 의해 미세하게 증가하는 경향을 보였다. 정백 소비전력량은 조질곡온이 0℃보다 높은 조건이 2.52~14.28% 감소하는 것으로 나타났다. 따라서 동절기 정백시 현미의 적정 온도는 10℃ 이상으로 조질하거나 유지하는 것이 적절한 것으로 판단된다. This study was find out the relationships between whiteness, hardness, crack ratio, broken rice ratio, increased grain temperature, moisture content, electric energy consumption, and optimum conditioning of grain temperature for milled rice efficiency and quality maintenance during the milling process of brown rice at low temperature. There was no significant difference between the whiteness variations of white rice after milling process when the conditioning grain temperatures ranging from 0 to 20℃ was used. The crack and broken rice ratios of white rice and the hardness of brown rice decreased with an increased in the conditioning grain temperature. Conditioning grain temperatures of 12, 20℃ are applicable to appropriated standard of temperature (15℃) after milling process. In the case of low temperature of grain, there was steadily increase the rate of change moisture contents because of dew condensation. There was 2.62∼14.28% decline of electricity energy for milling process when temperature of grain was higher than 0℃. Therefore it needs to control temperature over 10℃ for appropriate milling in the winter season.

Methotrexate 치료를 받고 있는 활동성 류마티스 관절염 환자에서 etanercept의 유효성과 안전성에 관한 연구

최병렬,강태영,정청일,이혜순,엄완식,김태환,전재범,유대현,배상철 대한내과학회 2004 대한내과학회지 Vol.66 No.5

목적 : 류마티스 관절염을 앓고 있는 한국인 중에 기존 DMARDs로 치료 실패하였고, 고정용량의 MTX를 복용하고 있는 환자들에 있어서 etanercept의 유효성과 안전성을 평가하고자 하였다. 방법 : 기존 DMARDs로 치료 실패한 활동성 류마티스 관절염 환자 76명을 대상으로 하여 단일군, 공개시험을 하였다. 대상 환자들은 고정용량의 MTX를 복용하면서 etanercept 25 mg을 1주일에 두 번 피하 주사하였으며 12주간 투여하였다. 유효성은 ACR 20, ACR 50,조조강직 시간으로 평가하였고, 약제의 안전성은 이상반응 등으로 평가하였다. 결과 : 대상 환자는 총 76명으로 평균 연령은 45.2세, 남자 5명, 여자 71명이었다. 84.4%인 54명이 12주째에 ACR 20을 만족하였고, 53.1%인 34명이 12주째에 ACR 50을 만족하였다. 조조 강직 시간은 치료 전 203.3분에서 치료 12주째 42.6분을 평균 74.5% 호전되었다. 가장 흔한 이상반응은 주사부위 반응이었다. 이외에도 상기도 감염, 오심, 안면부종 등이 발생하였으나 심각한 부작용은 없었다. 결론 : etanercept는 효과적이고, 안전한 류마티스 관절염 치료 방법이며 특히 MTX치료에도 불구하고 활동성인 류마티스 관절염에 기대되는 치료라고 할 수 있다. Background : This study was performed to investigate the efficacy and safety of etanercept in active rheumatoid arthritis patients with stable dose of methotrexate in Korean. Methods : In a 12 week, single arm, open trial, we assigned 76 patients with active rheumatoid arthritis who had an inadequate response to disease-modifying antirheumatic drugs. Patients received twice-weekly subcutaneous injections of etanercept 25 ㎎ while containing to receive methotrexate at a stable dose of 7.5~25 ㎎ per week. The clinical response was defined as the percent improvement in disease activity according to the criteria of the American Collage of Rheumatology (ACR) at 12 weeks. Results : Etanrecept led to significant improvements in disease activity and was safe and well tolerated. At 12 week, 84.4% of the patients receiving 25 ㎎ of etanercept achieved a 20% ACR response, and 53.1% of those receiving etanercept achieved a 50% ACR response. The most common adverse event was injection-site reaction. Other advanse events were upper respiratory infection, nausea, and facial edema, but there were no serious adverse events associated with etanercept. Conclusion : In active rheumatoid arthritis patients, etanercept was safe, well tolerated, and provided rapid clinical improvements.

6-Sigma경영혁신기법 시행에 따른 방사선과 내부고객만족도의 변화

이근옥,박재성,강충환,김미영,김승식 한국의료QA학회 2005 한국의료질향상학회지 Vol.12 No.1

Background : The concept of 'service' in a hospital is based on the quality of medical staffs who serve as customer-satisfying media, and this is what distinguishes general hospitals from other business corporations in which customer satisfaction is achieved through commercial products. Thus, the internal employee satisfaction is essential in the improvement of the 'service' and subsequent 'competitiveness' of a hospital. The purpose of this study is to establish internal marketing strategies for a general hospital through regular surveys on employee satisfaction. Method : Surveys on employee satisfaction in radiology department were conducted regularly twice a year in a university hospital with 800 beds 2001 in 2004. The subjects of this study were 35 employees who work in radiology department. The authors developed the questionnaires and the surveys were conducted initially during the first 6 months of the year. After necessary improvements were made by applying 6 Sigma techniques, subsequent surveys were conducted during the latter 6 months of the year and the degree of employee satisfaction was compared. Results : Overall satisfaction increased with a constant rate and the authors were able to assess that the hospital is being gradually stabilized. The degree of satisfaction assessed by multiple choices showed only minor changes. However, as a result of focusing on the demands put forth by the employees through the open questions, the degree of satisfaction increased gradually year after year. Conclusions : It is important to heighten the internal employee satisfaction systematically and harmoniously through the assessment on the demands of the internal customers and feedback-based communications between the management officers and the staffs. Continuous surveys on the internal employee satisfaction will serve to be valuable materials in the establishment of internal marketing strategies for a general hospital.