One step bulk modification of poly(L-lactic acid) composites with functional additives to improve mechanical and biological properties for cardiovascular implant applications

Kang, Eun Young,Choi, Bogyu,Park, Wooram,Kim, Ik Hwan,Han, Dong Keun Elsevier 2019 Colloids and Surfaces B Vol.179 No.-

<P><B>Abstract</B></P> <P>Poly(L-lactic acid) (PLLA) has been widely used as a promising biomaterial in biomedical applications due to its biodegradability and high mechanical strength. However, because of the inherent brittleness, low impact resistance, and weak thermal stability of PLLA, the modification process is usually required to utilize it for biomedical devices. Furthermore, acidic byproducts resulting from the hydrolysis of PLLA after implantation reduce the pH of the surrounding environment and cause inflammatory responses in the implanted area, leading to the failure of their clinical applications. To this end, here, we demonstrate a novel modification process for the PLLA composite with various functional additives, such as cis-aconitic anhydride (AA), triacetin (TA), isosorbide derivative (ISB), and/or Pluronic® F127 (F). The modified PLLA composite with TA and F (PLLA/TF) showed significantly improved elongation at break and Young’s modulus and retained tensile strength. Moreover, incorporating magnesium hydroxide (MH) nanoparticles (PLLA/TFMH) significantly reduced acid-induced inflammation responses caused by the acidic degradation products of PLLA. Reduced plasma protein adsorption was observed in the PLLA/TFMH. These results suggest that the one step bulk modification of biodegradable PLLA using TA, F, and MH will have great potential in cardiovascular implant applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Improved mechanical properties of PLLA via one step bulk modification with TA and F. </LI> <LI> Reduced acid-induced inflammation via one step bulk modification of PLLA/TF with MH. </LI> <LI> Increased homogeneity of MH distribution in one step bulk modified PLLA/TFMH. </LI> <LI> Enhanced hemocompatibility of PLLA/TFMH. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

식품공장폐수의 활성오니처리중 오존에 의한 산화분해효과

강경수,최영찬,하진환,송대진 濟州大學校 工科大學 産業技術硏究所 1991 産業技術硏究報告 Vol.2 No.-

For the increase of treatment efficiency when waste water which included residual chlorine was biologically treated with activated sludge, elimination efficiency of COD and change of transmittance by activated sludge method were examined after the treatment of residual chlorine with ozone of 100 volt and l0ℓ-air/min., 0.8g-0_(3)/hr. in velocity. The results were as follows. 1) When the sample which included residual chlorine was treated with ozone of 0.8g-O_(3)/hr., COD removal rate by the change of pH and ozonization time was more efficient than acidity solution of pH 3.2(20%) and alkaline solution of pH 12.0(10%). Since the COD removal rate become 35% after 50 minutes of ozonization time at neutral solution of pH 7.2. 2) After the residual chlorine included sample was treated with ozone for 50 minutes to make the F/M rate of 0.1㎏·BOD/㎏·MLSS, the sample was reacted with activated sludge for 3, 6, 9 and 15 hours. The 6 hours reaction gave 85.8% COD elimination which showed higher efficiency than 60.5% by Na_(2)S_(2)O_(3) treatment togather with shorting efficiency of reaction time. 3) When such sample as polyphenol which gives dark brown color was treated with ozone for 50 minutes after being made into acidic, neutral and alkaline solution. the transmittance increased from 30- 40% to 70% and gave better result in alkaline solution.

울산객사의 해체과정과 원형추정에 관한 연구

강영환,김윤경 대한건축학회 2005 대한건축학회논문집 Vol.21 No.1

Gaeksa means one of most important institution in provincial government during la-sean dynasty It was also used as a kind of hotel for foreign envoys or official guests More Importantly Gaeksa was a symbol of royal palace In which have held ceremony there twice in a month to make an obedience to the royalty It was also one of major landmarks of old City Under the Japanese colonialism, however, most of Gaeksa have been destroyed Very few are preserved with the original forms except partly remained or reconstruction Fortunately Ulsan Gaeksa remains lots of photos with which can be presumed the original form As for searching the original forms of buildings, the photos were needed And 12 phothos are very useful for searching the architectural characteristics of Gaeksa building With these data, this study proposes the presumed drawings of original form of Ulsan Gaeksa

24주간 추적하는 임상 연구에서 한국인 남자 알코올 의존 환자의 비재발률

강철중,김성곤,남궁기,조동환,이병욱,최인근,최용성,박성봉,제영묘,김현경,김성연 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.1

Objetives : In order to provide useful data tbr the further clinical studies with Korean alcohol-dependent patients, enrollment and non-relapse rates were investigated while alcohol-dependent patients wcre followed up for 24 weeks. Methods : The subjects of this study were alcohol-dependent male patients who, for the first time, visited a hospital among 3 groups of hospitals, University Hospital, General Hospital or Mental Hospital, or those who needed to be followed up after discharge from those hospitals. After assigning 12 subjects to each hospital, we investigated enrollment and non-relapse rates while cognitive-behavioral therapy and pharmacotherapy were provided. Results : 1) Forty-eight patients were enrolled and the rate of enrollment was 36.4%. The enrollment rate in the University Hospital group was 52.1%, in the General Hospital group 50.0%. and in the Mental Hospital group 10.4%. 2) In 48 patients, non-relapse rate was 27.1% at 12 week and 18.8% at 24 weeks after starting follow-up. It was 24.4% and 20.0% at 12 and 24 weeks, repectively, in the University Hospital group while the General Hospital group showed 33.3% and 16.7%, respectively, and the Mental Hospital Group showed 20.0% at both 12 and 24 weeks. Conclusion : These results provide important data for further clinical studies of Korean alcohol-dependent patients.

Trioctylamine에 의한 유기산의 추출

강안수,이병철,이한섭,안형환,이영주,류운형 明知大學校 産業技術硏究所 1993 産業技術硏究所論文集 Vol.12 No.-

For elucidation of various parameter's effect on the reactive extraction of organic acidstrioctylamine(TOA)-diluents system, the association model, equilibrium constants and extraction factors(loading) were investigated . The organic acids rosed were propionic. succinic, masonic, and benzoic acid. Extractant was tertiary amine, TOA and diluents were butylaeohol, hexane, and benzene. It was concluded that the loading of monobasic acid of propionic acid were higher than that of dibasic acids of oxalic, and malonic acid with extranctant TOA. In the extraction of monobasic acid the extraction factor was not affected by the initial concentration of extractant amine, but in the extraction of dibasic acids the extraction factor was getting better with decreasing the initial concentration of amine. There was a strong effect of diluents upon the extractien factor, and the order of these factor was as shown below: xylene<Benzene<butylalcohol<choloroform<methylisobutylketone.

관상동맥질환 환자에서 스텐트 시술 후 재협착에 관한 연구

강진환,권영주,박상호,한대희,이상철,김명구,변정득,최병조,심규혁,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and aims : In the coronary artery disease, a rate of restenosis was much decreased by placement of coronary stent than when percutaneous transluminal coronary angioplasty has been applied, but there are still important clinical problems of restenosis. There has been many progressive studies about various factors contributed to this restenosis. So, we studied a relation between restenosis after placement of coronary stent in the coronary artery disease and many clinical factors, characteristics of stenotic lesion and procedural factors, and also assessed the restenosis rate of various coronary stents. Methods : Total 58 lesions(46 cases of patients ; man 30, woman 16) were evaluated, which has been performed a follow-up coronary angiography after 6 months (mean 188 days) since coronary stent had been placed. Various stents were implanted and assessed a relation between restenosis and many factors. Results : Of 58 lesions were target stenotic studies, there were 22 of restenotic lesions(37.9%), and the restenosis rate wes statistically significant difference in the relation with diabetes mellitus(p<0.05), group of acute myocardial infarction(p<0.05) among clinical diagnosis of ischemic heart disease(stable angina, unstable angina and acute myocardial infarction) in clinical factors and with high dilation pressure of stent(p<0.05) in procedural factors. When the rate of restenosis was evaluated among implanted stents, it was lowest in the Multilink^(®) stent and highest in the Nir Royal^(®) stent(60%). Conclusion : In this study of restenosis and various factors after placement of stents in the coronary artety disease, factors such as diabetes mellitus, group of acute myocardial infarction and a dilation pressure of stent were significant related with restenosis and the restenosis rate of Multilink^(®) stent was lowest and the highest restenosis rate was of Nir Royal^(®) stent.

食品工場廢水의 活性汚泥處理中 오존에 依한 酸化分解效果

康京壽,崔永贊,宋大鎭,河璡桓 濟州大學校工科大學附屬産業技術硏究所 1991 尖端技術硏究所論文集 Vol.2 No.-

잔류염소를 함유한 發水를 活性汚泥에 의한 處理效率을 增加시키기 위하여 전압 100Volt, 유속 10ℓ-air/min, 0.8g-O₃/hr의 오존으로 처리했을때 COD의 除去效果및 투과율의 變化를 實驗한 結果를 要約하면 다음과 같다. 1. 잔류염소를 함유한 시료를 0.8g-O₃/hr의 오존으로 處理하였을때 pH의 變化 및 反應時間에 의한 COD의 除去率은 中性溶液(pH=7.2)에서 오존處理時間 50分 후 35%의 除去效果를 나타내어 酸性溶液(pH=3.2)의 20%, 알칼리性溶液(pH=12.0)의 10%의 除去效果보다 좋았다. 2. 잔류염소를 함유한 試料를 오존으로 50分間 處理하여 F/M比 0.1㎏·BOD/㎏·MLSS로 한 후 3. 6. 9 및 15時間 活性汚泥로 反應시켰을 때 反應時間 6時間 후 85.8%의 COD의 除去效果가 있어 티오황산나트륨(Na₂S₂O₃)으로 處理한 試料의 除去率 60.5%보다 좋았으며, 反應時間의 단축효과도 있었다. 3. Polyphenol色素 等 暗褐色을 띄는 試料를 酸性, 中性, 알칼리性 溶液으로 하여 오존으로 50分間 處理하였을 때 투과율이 30~40%에서 70% 以上 상승하였으며 알칼리성溶液에서가 투과율이 더 좋았다. For the increase of treatment efficiency when waste water which included residual chlorine was biologically treated with activated sludge, elimination efficiency of COD and change of transmittance by activated sludge method were examined after the treatment of residual chlorine with ozone of 100 volt and 10ℓ-air/min., 0.8g-O₃/hr. in velocity. The results were as follows. 1) When the sample which included residual chlorine was treated with ozone of 0.8g-O₃/hr., COD removal rate by the change of pH and ozonization time was more efficient than acidity solution of pH 3.2(20%) and alkaline solution of pH 12.0(10%). Since the COD removal rate become 35% after 50 minutes of ozonization time at neutral solution of pH 7.2. 2) After the residual chlorine included sample was treated with ozone for 50 minutes to make the F/M rate of 0.1㎏·BOD/㎏·MLSS, the sample was reacted with activated sludge for 3, 6, 9 and 15 hours. The 6 hours reaction gave 85.8% COD elimination which showed higher efficiency than 60.5% by Na₂S₂O₂ treatment togather with shorting efficiency of reaction time. 3) When such sample as polyphenol which gives dark brown color was treated with ozone for 50 minutes after being made into acidic, neutral and alkaline solution, the transmittance increased from 30-40% to 70% and gave better result in alkaline solution.

중 란탄족 산화물의 결합구조와 전기전도성

강영환,최재시,윤기현 연세대학교 대학원 1980 延世論叢 Vol.16 No.2

The electrical conductivity of highly pure polycrystalline Gd₂O₃, Ho₂O₃ and Yb₂O₃ has been measured from 650 to 1050℃ under oxygen pressure range of 10^(-6) to 10² torr. Plots of logσ vs. T at constant oxygen pressure are found to be linear. and the conductivity dependence of oxygen pressure in the high temperature region (750-1050℃) is approximated by σ α po₂1/5.3. This shows that the conduction mechanism is associated with doubly ionized metal vacancies. Fairly low activation energy and the lack of oxygen pressure dependence are found over the temperature range of 650 to 750℃. The conduction mechanism is explained by not metal vacancies, but hopping oxygen ions in the oxides. The sesquioxides exhibit mixed conduction with some ionic conduction and major electronic conduction carriers.

전도도계의 제작에 관한 연구

강용환,최석남,박병빈 공주대학교 사범대학 과학교육연구소 1980 과학교육연구 Vol.12 No.1

A low-cost student type conductance meter have been developed for the measurement of conductivity of electrochemical system. This instrument measures an impedance range from ?? Ohm with 2% accuracy. And this instrument could be applied to measure the rapid chemical reaction.