Preparation of Thermo-Responsive and Injectable Hydrogels Based on Hyaluronic Acid and Poly(N-isopropylacrylamide) and Their Drug Release Behaviors

Ha Dong In,Lee Sang Bong,Chong Moo Sang,Lee Young Moo,Kim So Yeon,Park Young Hoon The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.1

Copolymers composed of hyaluronic acid (HA) and poly(N-isopropylacrylamide) (PNIPAAm) were prepared to create temperature-sensitive injectable gels for use in controlled drug delivery applications. Semi-telechelic PNIPAAm, with amino groups at the end of each main chain, was synthesized by radical polymerization using 2-aminoethanethiol hydrochloride (AESH) as the chain transfer agent, and was then grafted onto the carboxyl groups of HA using carbodiimide chemistry. The result of the thermo-optical analysis revealed that the phase transition of the PNIPAAm-grafted HA solution occurred at around 30$\∼$33$^{circ}C$. As the graft yield of PNIPAAm onto the HA backbone increased, the HA-g-PNIPAAm copolymer solution exhibited sharper phase transition. The short chain PNIPAAm-grafted HA ($M_{w}$=6,100) showed a narrower temperature range for optical turbidity changes than the long chain PNIPAAm-grafted HA ($M_{w}$=13,100). PNIPAAm-grafted HA exhibited an increase in viscosity above 35$^{circ}C$, thus allowing the gels to maintain their shape for 24 h after in vivo administration. From the in vitro riboflavin release study, the HA-g-PNIPAAm gel showed a more sustained release behavior when the grafting yield of PNIPAAm onto the HA backbone was increased. In addition, BSA released from the PNIPAAm-g-HA gels showed a maximum concentration in the blood 12 h after being injected into the dorsal surface of a rabbit, followed by a sustained release profile after 60 h.

고분자 수지를 이용한 자동차 에어컨용 압축기의 씰에 관한 연구

정태형,하영욱 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.5

The existing compressor steel seal used in automotive air-conditioner has the problem of oil leakage and deterioration in shielding performance, due to the abrasion and corrosion of the material. A new type of polymer resin seal studied in this research has the characteristics of high anti-abrasiveness and anti-corrosiveness, which can overcome the defects of the steel seal. In addition, the seal needs lower manufacturing cost and is appropriate to mass production, because it is made by the injection molding method requiring no mechanical processing. The profile generation program for seal mold has been developed using the gradient method, and the molding characteristics of the seal have analyzed through the flow analysis and the warpage analysis. The program has been verified by comparing the analysis results with the measured data of the test product. The research might be said to provide the basic method to produce the polymer resin seals with various types and dimensions.

PEI계 복합 재료를 이용한 탄자 운반체의 사출 성형 기술 개발에 관한 연구

정태형,이범재,하영욱,이성계 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-

This research covers the development of new technique for composite injection molding of high stiffness Sabot. An analysis of polymer resin is performed by means of making test specimen mold and doing test with accordance of ASTM test guidelines. Structural analysis and simulation of injection molding process are carried out in order not only to estimate but also to predict the characteristics of molding stresses what both product and structure of mold may have. For structural analysis software, Mold flow and LS-dyna are used and universal test machine is utilized for evaluating performance of sabot. Cases of adopting this material to sabot are not announced yet in domestic academic world. In addition to that, materials for polymer-metal mixed injection molding are imported on the whole due to deficient level of domestic technology. Therefore, this new developed injection molding technique using PEI material can make it available to ensure the technology of making mold, injection and design. Finally, this technique may be applicable to another sabot having different radius of warheads from now on.

플라스틱 기어의 피로수명 평가 및 수명 예측

정태형,강성규,하영욱 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

Through the fatigue test of plastic gears using polyacetal polymer, this research aims at providing basic data for not only specifying operation conditions of plastic gears, but also designing dimensions of plastic gears with giving fatigue life and the estimated equation of fatigue life of plastic gears. That is, from the fatigue life curves, the estimated equation of fatigue life of plastic gears is taken out. For the estimated equation of fatigue life of plastic gears, this research provides two test methods; one is preserving non-limited temperature of tooth flank, the other is preserving limited temperature of tooth flank. As results, how the temperature of tooth flank affects the fatigue life is shown. In addition, based on the endurance limit, the essential factors of the unit load and K-factor are determined, which are needed in the design of gear by bending strength and surface durability.

고분자 수지를 이용한 자동차 에어컨용 압축기의 씰에 관한 연구

정태형,하영욱 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

The existing compressor steel seal used in automotive air-conditioner has the problem of oil leakage and the deterioration in shielding performance, due to the abrasion and the corrosion of the material. A new type of polymer resin seal is studied in the research. The polymer resin seal has the characteristics of high anti-abrasiveness and anti-corrosiveness, which can overcome the defects of the steel seal. In addition, the seal needs lower manufacturing cost and is appropriate to mass production, because it is made by the injection molding method requiring no mechanical processing. The profile generation program for seal mold has been developed using the gradient method, and the molding characteristics of the seal have analyzed through the flow analysis and the warpage analysis. The program has been verified by comparing the analysis results with the measured data of the test product. The research might be said to provide the basic method to produce the polymer resin seals with various types and dimensions.

Sezary증후군과 병발된 용혈성 빈혈 1예

유광하,진춘조,김홍승,이종인,심영학,정순희,이창훈 건국대학교 의과학연구소 1997 건국의과학학술지 Vol.- No.7

요로조영상에서 요관폐색 및 음영결손을 보인 환자에서의 요관경검사

염규영,하용원,노안식,손성용,김진겸,설종구 충남대학교 의과대학 지역사회의학연구소 2000 충남의대잡지 Vol.27 No.2

Purpose: To evaluate the clinical value of ureteroscopy for the ureteral filling defect or obstruction on the excretory or retrograde pyelogram(RGP). Materials and Methods: The 72 patients with filling defect or intrinsic obstruction ureteral lesion on the excretory urogram or RGP underwent ureteroscopy to examine and treat the lesions. We used the 9.5Fr. or 11.5Fr. rigid ureteroscope with 5Fr. working channel. Results: The results were as follows; I. Among the 72 patients, 39 were male and 33were female. The mean age of patient was 45.7 years. 2. Ureteroscopy was successfully performed in 70 cases(97%) out of 72. In 2 cases, the advance of ureteroscope was failed. 3. Among 70 successful cases, ureteroscopy revealed 45 radiolucent stones, 9 ureteral stricture, 2 ureteral TCC. I metastatic tumor, 3 blood clot, each case of ureteral polyp, epithelial hyperplasia and Von-Brunn's nest. In 7 cases, no causative lesions were identified. 4. 41 out of 45 radiolucent stones were successfully removed by ureteroscopic procedure and 9 ureteral strictures were dilated. 6 cases of ureteral mass were successfully biopsied for pathological diagnosis. 5. 23 cases of post-operative or fever were treated conservatively and 10 cases of mucosal tearing and 1 case of ureteral perforation were treated with double-J stent indwelling. Conclusions: The ureteroscopy is effective modality to evaluate and treat in the ureteral filling defect or obstruction on the excretory urogram.

骨盤腔內 巨大 橫紋筋肉腫 1 例

金瑩洙,河泰原,朴滿洙,姜瞬求,李重禾,尹栗老,薛鍾求 충남대학교 의과대학 지역사회의학연구소 1992 충남의대잡지 Vol.19 No.2

Rhabdomyosarcoma, which is a very rare and highly malignant disease in urologic field, has three categories-pleomorphic, alveolar, embryonal, and may arise from any part of the body that contains embryonal mesenchyme, whether striated muscle tissue is present or not. The common site in the genitourinary tract are prostate, bladder, and vagina. Herein we experienced a rhabdomyosarcoma of the pelvic cavity and reviewed literature briefly.

Sezary증후군과 병발된 용혈성 빈혈 1예

유광하,진춘조,김홍승,이종인,심영학,정순희,이창훈 건국대학교 의과학연구소 1997 건국의과학학술지 Vol.7 No.-

저자등은 전신적인 소양감을 동반한 홍반성 판상의 피부 병변과 자가 면역성 용혈성 빈혈이 동반된 Sezary 증후군을 진단하고 복합 화학 요법 CHOP으로 치료하여 피부 증상과 빈혈이 호전된 예를 문헌고찰과 함께 보고하였다. Sezary syndrome(SS), a leukemic variant of cutaneous T-cell lymphoma(CTCL), is monoclonal proliferation of CD4 T-cell having cerebriform nuclei in the skin and the peripheral blood. It is associated with erythroderma, pruritis, lymphadenopathy with protracted clinical course and systemic spread. We present a case of SS i a 38-year-old woman with generalized exfoliative erythroderma, plaques, and pruritus. Histopathologic findings of the skin lesions revealed infiltration of atypical lymphocytes in the dermis and epidermis. Electron microscopic findings of peripheral blood and skin showed atypical lymphocytes with cerebriform nuclei. Laboratory findings revealed direct Coombs' positive autoimmune hemolytic anemia, a rare association of SS. Chemotherapy with CHOP produced improvement of the skin manifestation and anemia.

長週期 核燃料 貯藏施設에서의 放射線遮蔽解釋

李汰永,河正雨,陸鍾澈 대한방사선 방어학회 1984 방사선방어학회지 Vol.9 No.2

長週期核燃料 爐心技法에 의한 使用後燃料가 旣存 使用後核燃料貯藏施設의 設計變更없이 同 施設에 受容 可能한지를 決定하기 위하여 貯藏施設에서의 豫想 放射線被曝線量率을 DLC-23/CASK(22n, 18g) 斷面績資料와 ANISN-W 電算코드로 計算하여 設計基準値와 比較·檢討하였다. 使用後核燃料內容의 放射能量 및 감마선스펙트럼은 核燃料交替모델에 따라 ORIGEN 電算코드로 計算하였다. 放射線量率의 計算에 있어서 貯藏槽의 幾何學的 모델은 無限平板模型이며 貯藏된 使用後核燃料의 構成物質과 放射線源은 核燃料集合體內에 均一하게 分包되었다고 假定하였다. 使用後核燃料貯藏槽에 貯藏된 核燃料集合體 및 貯藏用水中 放射性核種에 의한 放射線量率의 計算結果는 正常 및 事故水面時 計算된 放射線量率이 設計基準値를 滿足시켜주는 것으로 나타났다. Estimated dose rates in spent fuel pool storage with the extended fuel cycle core management were reviewed and compared with design limit after calculation with the aid of DLC-23/CASK(22n, 18g) nuclear data and ANISN code. Radioactivity and gamma spectrum within spent fuel assemblies were calculated with ORIGEN code by extended fuel cycle model. In the calculation of dose rate, the fuel pool geometry was assumed to be infinite slab. Also, composition materials and radiation source within assemblies which are being stored in pool storage were assumed to be uniformly distributed throughout all the assemblies. As a result of calculation of dose rate from stored assemblies and waterborne radionuclides in pool water, the calculated dose rates appear to be lower than design basis limit under normal condition as well as abnormal condition.