Rheology of Decamethylceclopentasiloxane (cyclomethicone) W/O Emulsion System

Choi, Min-Hyung,Jeong, So-Ra,Nam, Sang-In,Shim, Sang-Eun,Chang, Yoon-Ho The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.12

A highly dispersed W/O emulsion of silicone oil (cyclomethicone)/water system was prepared with a nonionic surfactant. The surface and interfacial tension between the oil and water were characterized in terms of the droplet size distribution and viscosity change of the emulsion. When the dispersed phase concentration was relatively high, the viscosity of the emulsion was rapidly increased and the droplet size of the emulsion was decreased. The rheological behavior of the emulsion system showed non-Newtonian and shear thinning phenomena depending upon the content of the dispersed phase. The droplet size of the emulsion was decreased with increasing surfactant content and water concentration. The relative viscosity of the emulsion was better predicted with the Choi-Schowalter model than with the Taylor model. The value of the complex modulus increased with increasing surfactant concentration. The linear viscoelastic region was expanded with a dispersed phase concentration. According to the change in the viscosity, the behavior was classified into three distinct regions: [I] linear viscoelastic, [II] partially viscoelastic, and [III] viscous. The creep/recovery behaviors in each region were characterized.

Microspheres: Synthesis of Monodispersed Microspheres from Laplace Pressure Induced Droplets in Micromolds (Adv. Mater. 37/2012)

Choi, Chang‐,Hyung,Jeong, Jae‐,Min,Kang, Sung‐,Min,Lee, Chang‐,Soo,Lee, Jinkee WILEY‐VCH Verlag 2012 ADVANCED MATERIALS Vol.24 No.37

<P>A novel synthesis method for microspheres using micromolds based on the Laplace pressure difference is presented by Jinkee Lee, Chang‐Soo Lee, and co‐workers on page 5078. This simple micromolding technique makes it possible to synthesize highly monodispersed microspheres with the flexibility of various reaction schemes, such as photopolymerization, sol‐gel reactions, and colloidal assembly. This method is promising for the mass production of various sizes of monodispersed microspheres without the need for complicated control of fluids. </P>

CA 19-9 상승을 동반한 무증상의 위 이소성 췌장

김형일 ( Hyung Il Kim ),박창환 ( Chang Hwan Park ),전충환 ( Chung Hwan Jun ),이기훈 ( Gi Hoon Lee ),김현수 ( Hyun Soo Kim ),최성규 ( Sung Kyu Choi ),유종선 ( Jong Sun Rew ) 대한내과학회 2008 대한내과학회지 Vol.74 No.6

저자들은 CA 19-9 상승을 동반한 무증상의 위 이소성 췌장을 내시경 점막하 박리술을 통하여 확진 및 제거하였으며 추적 검사에서 CA 19-9의 정상화를 경험하였기에 보고하는 바이다. Ectopic pancreas is an uncommon clinical finding, and it is rare for heterotopic pancreatic tissue to cause symptoms. The most common sites for ectopic pancreas are the submucosal layer of the stomach and the small intestine. An ectopic pancreas is subject to various pathological changes occurring in the pancreas itself, namely cyst, pancreatitis, hemorrhage, abscess, necrosis, and neoplastic changes. We report a case of a gastric ectopic pancreas associated with elevated serum carbohydrate antigen 19-9 (CA 19-9). We performed endoscopic submucosal dissection for histologic diagnosis and removal of the submucosal tumor in the stomach, and histological examination confirmed ectopic pancreas tissue. One months later, serum CA 19-9 declined to a normal level.(Korean J Med 74:663-666, 2008)

Dipyridamole 부하 심근 SPECT에서 Dipyridamole의 작용과 부작용

고창순(Chang Soon Koh),이명철(Myung Chul Lee),정준기(June Key Chung),이동수(Dong Soo Lee),최창운(Chang Woon Choi),배상균(Sang Kyun Bae),양형인(Hyung In Yang),여정석(Jeong Suk Yeo) 대한핵의학회 1993 핵의학 분자영상 Vol.27 No.2

N/A Dipyridamole is an agent that may be used to noninvasively evaluate coronary artery disease. The effect of dipyridamole infusion its generally related to its induced peripheral vasodilatory effect. In normal person, heart rate is generally increased slightly while blood pressure decrease, but the achieved double product and related myocardial oxygen consumption have no significant change. The purpose of this study is to examine the effect and side effect of dipyridamole, and to compare different response to dipyridamole among the patients. We evaluated 847 patients who underwent dipyridamole stress myocardial SPECT. 93.6% of them had induced hypotension 0.9% showed no change of blood pressure, 5.5% had increased blood pressure 8.3% had no change of pulse rate more than 10% of basal pulse rate. Among diabetes, 16.9% was not change of pulse rate, 6.7% in non-diabetes. There was no significant correlation between age and rate pressure product rest(RPPr), in patients without perfusion defects on SPECT(y=7.1x+48.4r=0.13 p>0.01). As increasing age, RPPs/RPPr was declined(y=-11.6x+68.9 r=0.17 p〈0.01), similar results were obtained in patients with perfusion defect. The size of perfusion defect on myocardial SPECT have no correlation between RPPr and RPPs/RPPr. The side effects of dipyridamole included chest pain and chest tightness, headache, abdominal pain, dizzness, nausea, and dyspnea. As increasing age, dipyridamole-induced cardiac work at rest was increased, cardiac response to dipyridamole was decreased.

강릉수력발전소 발전수 방류 전후의 남대천 수질과 미생물 분포

심혜숙,김규중,김형섭,최창근,전방욱 江陵大學校東海岸地域硏究所 1993 東海岸硏究 Vol.4 No.1

강릉수력발전소의 발전수 방류가 강릉 남대천의 수질 및 미생물 분포에 미치는 영향을 조사하였다. 정점 3 상류지역의 발전수 방류는 수질에 상당한 영향을 끼쳐 정점 3 및 정점 4의 수질은 악화되고 정점 5, 정점 6 및 정점 7의 수질은 개선되었다. 미생물 분포도 이와 유사하여 정점 3 및 정점 4의 세포수는 상당히 증가한 반면 정점 5, 정점 6 및 정점 7에서는 대체적으로 감소하였다. 이 결과로 미루어보아 강릉수력발전소의 발전수는 희석효과에 의해 수질 및 미생물 분포를 변화시키는 것으로 사료된다. The effects of water discharged from Kangnung hydropower plant on the water quality and some bacterial population of Namdaecheon Stream, Kangnung were investigated. The water discharged above station 3 affected the water quality significantly; the water quality of station 3 and station 4 took a turn for the worse, however those of station 5, station 6 and station 7 changed for the better. It was also true with the bacterial population; The number of cells of bacteria increased in station 3 and 4, but the number significantly decreased in station 5, station 6, and station 7. The data suggested the idea that the water discharged from Kangnung hydropower plant changed the water quality and some bacterial population by dilution effect.

In Vitro 고삼투압이 정자 원형질막의 Protein Tyrosine Phosphorylation에 미치는 영향

오영근,장재호,최인호,정노팔,신형철,곽병주 대한의생명과학회 2000 Journal of biomedical laboratory sciences Vol.6 No.4

정자의 원형질막은 삼투압에 의해서 영향을 받는다고 보고되고 있다. 이중 세포막내 분자구조의 변화 특히 막지질 구조의 변화와 동반되는 이온채널의 변화 그리고 Ca2+과 HCO-3의 유동성과도 밀접한 관련이 있는 것으로 보고되고 있다. 지금까지의 연구보고에 의하면, 정자의 첨체반응 (acrosome reaction)이 일어날 경우 protein tyrosine phosphorylation이 증가되는데 이것은 cAMP, protein kinase A 등을 통하여 작용되는 것으로 보고되고 있다. 막의 지질변화를 유도하는 물질로 일종의 sterol acceptor인 BSA가 알려져 있는 바, 실제로 BSA가 막지질 성분에 미치는 영향을 관찰한 결과 cholesterol이 유출되고 이온 등의 유동성 변화가 일어나, 이 유동성 변화가 정자의 adenylyl cyclase를 활성화시켜 cAMP를 증가시키고, PKA가 활성화되어 결과적으로 Protein tyosine phosphorycation이 유도된다고 보는 것이다. 침체반응과 protein tyrosine phosphorylation과는 밀접한 관계가 있는 것으로 사료되고 있다. 본 연구는 정자 원형질막에서 cholesterol이 유출되어 protein tyrosine phosphorylation이 유도될 때, BSA와 같은 sterol acceptor가 작용할 것이라는 전제하에, 고삼투압 하에서 탈수로 인해 원형질막이 위축되더라도 sterol acceptor가 존재한다면 막지질 성분의 구조적 변화가 억제 될 수 있을 것이라는 가설을 설정하였다. 실험결과, 저온 및 고삼투압 하에서 정자운동은 감소되지만 원형질막의 구조적 변화는 없고, 삼투압에 대한 반응정도는 원형질막을 통한 수분이동과 세포용적 변화에 따라 비례적으로 일어난다고 하는 사실을 발견하였다. 이 결과는 정자보존에 있어서 저온변화에 영향을 미치는 여러 인자들 특히 protein fgrosine phosphorylation의 증가와 밀접한 관계가 있음을 시시해 준다. 또한 sterol acceptor로 알려진 BSA는 삼투압이 변화되더라도 역시 중요한 인자로 작용할 수 있음을 알 수 있었으며, 특히 고삼투압으로의 변화는 cAMP와 protein kiname A를 거치는 신호전달과정에 있어서 중요한 요인이라는 사실을 확인할 수 있었다. It has been reported that plasma membrane activity of the spermatozoa may be susceptible to be influenced by extracellular osmolality and such membranous changes involve intracellular molecular changes, special regard to the structure of membranous lipids, and the accompanying ion-channel of which are closely related with their fluidity of Ca2+ and HCO-3. It is of common recognition that a certain kind of sterol acceptor player an important to induce lipid fluctuation of the sperm plasma membrane which have been influenced by BSA administration and came in effect to outflow of cholesterol from the spermatozoa and resulted in changes of ionic fluidity to facilitate adenylyl cyclase, and to induce protein tyrosine phosphorylation by increase of cAMP and activation of PKA. Thus it seems likely that an augmentation of the acrosomal reaction is closely related with protein tyrosine phosphorylation. The following experimental results were obtained in the present study; Under the high osmolality conditions, the spermatozoa motility declined significantly and the structural change of the plasma membrane diminished to confirm that the response degrees to the osmolality depended upon the water transfer volume through the plasma membrane and the changes of cellular volume. Those experimental results suggest that a physiological parameter such as low temperature condition played an important role for presentation of spermatozoa and that inducement of spermatozoa activation for reinforcement of protein tyrosine phosphorylation. On the other hand, it seemed likely that the BSA administration as one of sterol acceptors might represent a key role also under the high osmolality condition and their result also suggests that osmolality change, special regard to high osmolality condition may play an important role also in the processes of signal transmission

Electron Cyclotron Resonance O_2 Plasma에서 증착한 규소 산화 박막의 특성

안명환,서문석,장재선,서성모,이기방,윤창주,이형재,남기석,최규현,손춘배,김용섭,강석희 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.17 No.-

규소 산화막을 ECR-CVD(electron cyclotron resonance-chemical vapor deposition) 증착방법으로 5인치 기판위에 상온에서 증착하고, 증착공정조건인 증착율, 기판온도, 마이크로파의 세기변화 및 플라즈마 혼합기체의 비에 따른 규소 산화막의 특성을 조사하였다. 또한 산화막의 구조적인 특성을 비교하기 위해 FTIR을 이용하여 ECR-CVD 증착한 산화막, RPE-CVD(remote plasma enhanced-CVD) 증착한 산화막 및 열 산화막의 stretching frequency를 측정하였다. 측정된 결과 ECR-CVD로 증착된 산화막이 구조적인 면에서 열 산화막과 거의 같음을 보였다. ECR-CVD로 증착된 산화막의 전기적인 특성을 전류-전압 및 축전-전압 측정에의하여 분석하였다. 축전된 산화막의 전기적인 특성은 산화막의 전하 밀도는 1×10 exp (11)/㎠이였고, 평균 절연 파괴 전압은 약 6 MV/㎝이다. We have grown thin films of SiO_2 at room temperature by using an ECR-CVD system and have investigated the changes in the properties of the deposited films with changes in the processing conditions such as the deposition rate, the substrate temperature, the microwave power and the plasma gas mixing ratio. We also measured the stretching frequency of three kinds of oxides, and ECR-CVD-grown oxide, a PECVD-grown oxide, and a thermally grown oxide, using FTIR analysis to compare their structural properties. The result shows that the structural properties of the ECR-grown oxide are similar to those of the thermally grown oxide. Additionally, the electrical properties of the ECR-grown oxide were investigated by using current-voltage and capacitance-voltage measurements. These electrical results indicate that the oxide charge density and the average breakdown voltage are 1×10 exp (11) ㎝^-2 and 6 MV/㎝, respectively.

개선된 텍스쳐 정보를 이용한 갑작스러운 조명 변화에 강인한 이동 물체 탐지

오요한(Yoe Han O),장형진(Hyung Jin Chang),김수완(Soo Wan Kim),최진영(Jin Young Choi) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.10

Moving object detection is a fundamental technique in visual surveillance. Robust technique to enhance performance of moving object detection is required for several bad conditions in real external circumtance. In case of sudden illumination change in outdoor condition. many objects are determined as moving object though they are not really moving, but just their illumination changes. This makes the detection result untrustworthy. In this paper, robust moving object detecton to sudden illumination change using gaussian mixture background model and new texture information using background from the weighted sum of recent images is proposed.

상악 전치부 결손이 발음에 미치는 영향에 관한 연구

노창섭,최대균,우이형,최부병,Roh Chang-Sup,Choi Dae-Gyun,Woo Yi-Hyung,Choi Boo-Byung 대한치과보철학회 1992 대한치과보철학회지 Vol.30 No.3

This study was performed to investigate the phonetic alterations with upper anterior teeth were missing. To compare the changes of the phonations, before and after insertion of the temporary prosthesis, six subjects who lost their upper anterior teeth were selected (2-male, 4-female). Tested sounds (/ga(가), na(나), da(다), ra(라), sa(사), ja(자), cha(차), ta(타), pa(파), ha(하), gi(기), ni(니), di(디), ri(리), si(시), jl(지), chi(치), ti(티), pi(피), hi(히), seu(스), se(세), so(소), su(수)/were programmed into an IBM AT with and without temporary prosthesis. These experiments were analyzed by formants, consonants durations, and energy level changes with an LSI speech work station program. During the pronunciation of the tested sounds (with and without temporary prosthesis), mandibular movements were recorded to a Mandibular Kinesiogram and analyzed . The findings led to the following conclusions: 1. Objective differences could not be found. However, in every informant, subjective improvement could be noticed. 2. There were no persistant correlations of the formant's changes. And in every informant, phonetic changes were variable. 3. There were various changes of the consonant durations in every informant. By and large, those of /si(시), jl(지), chi(치), Pi(피), hi(히)/ were longer than other tested sounds. After insertion of the prosthesis, durations were shorter. Consonants with /i(ㅣ)/ were longer than with /a(ㅏ)/, with or without prosthesis. 4. With and without temporary prosthesis, mandibular movements were various in the frontal view. Mandibular movements showed lateral deviations, and mandibular positions with /si(시), ji(지), ti(티), seu(스), hi(히)/ were nearer to the mandibular rest position. 5. The kinds of temporary prosthesis and conditions of the missing teeth influenced every informant variously, so there were no correlation between informants. 6. Energy levels increased in all tested sounds with a fixed temporary prosthesis. And, there were no differences between before and after insertion of a removable temporary prosthesis. However, sibilant sounds, and consonants with /i(ㅣ)/ showed a little increased energy level.

수컷 골든 햄스터에서 광주기에 따른 Gonadotropin Releasing Hormone 유전자 발현

최돈찬,박창은,최형재 용인대학교 자연과학연구소 2000 自然科學硏究所論文誌 Vol.5 No.1

The sexual activity of golden hamsters is controlled by photoperiod(light/day), being active in summer and inactive in winter. Adult hamsters in a short day(SD, ≤12 hours of light/day) show gonadal regression at about 8 week regardless of sex. The regressed testes display remarkably lowered follicle-stimulating hormone and luteinizing hormone levels in blood. The synthesis and release of gonadotropins are well established to be regulated by the gonadotropin releasing hormone(GnRH). Thus, it is thought that SD curtails the release of GnRH. Removal of pineal gland always sustains the sexual activity. A proper treatment of melatonin, a major hormone secreting from the pineal gland, suppresses the sexual function, indicating the mediation by melatonin. Thus the expression of GnRH gene was examined in the hypothalamus depending on photoperiods in male golden hamsters. As results, GnRH gene was partially identified and detected concurrently in the preoptic area and mediobasal hypothalamus. Thus, photoperiod appeared not to affect the expression of GnRH gene. But the effects of SD was blocked by the removal of pineal gland. These results suggest that photoperiod and pineal gland do not affect the experession of GnRH gene but may affect the releasing mechanism of GnRH from hypothalamus of male golden hamsters.