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.

HA 라우팅 기반의 개선된 멀티캐스트 제공 방안

김인경(In-Kyeong Kim),하정락(Jeong-Lak Ha),현은희(Eun-Hee Hyun),김상하(Sang-Ha Kim) 한국정보과학회 2001 한국정보과학회 학술발표논문집 Vol.28 No.2Ⅲ

IETF Mobile IP는 이동 컴퓨팅 환경에서 IP 멀티캐스트를 지원하기 위한 메커니즘으로 HA 기반 라우팅과 FA 기반 라우팅을 간략히 언급하고 있다. FA 기반 라우팅의 경우, 단말기 이동 시 멀티캐스트 트리를 재구성하는 오버헤드가 존재하는 단점이 있다. 반연, HA 기반 라우팅의 경우, 단말기 이동시 경로 최적화가 이루어지지 않는 단점에도 불구하고, 멀티캐스트 트리 수정에 대한 오버헤드가 존재하지 않은 장점이 있다. 이러한 장점은 망의 안정성을 높일 수 있기 때문에 많은 연구에서 HA 기반 라우팅을 채택하고 있다. 하지만, 기존의 HA 기반 라우팅 방법에서 가장 큰 장애 요소는 터널링 집중화 현상이며, 이를 해결하기 위해 Mobile Multicast(MOM) 등에서 정성적인 방법을 제안하고 있지만, 구체적인 프로토콜이 없으며 모든 HA들이 관여하는 복잡도로 인해 실제로 망에 배치되는 데 한계성을 가진다. 본 논문에서는 현재의 Mobile IP 메시지의 간단한 확장과 FA에 멀티캐스팅을 위한 기능을 첨가하여, 터널링 집중화 현상을 해결하는 프로토콜을 제안하고자 한다. 제안되는 프로토콜은 현재의 모든 IP 멀티캐스트를 수용하고, Mobile IP와의 호환성을 유지한다.

논문 : 강원도 양양지역 소나무림의 지상부 바이오매스와 수관층 연료특성에 관한 연구

김성용 ( Sung Yong Kim ),이영진 ( Young Jin Lee ),장미나 ( Mi Na Jang ),서연옥 ( Yeon Ok Seo ),구교상 ( Kyo Sang Koo ),정성철 ( Sung Cheol Jung ),김경하 ( Kyung Ha Kim ) 한국임학회 2012 한국산림과학회지 Vol.101 No.2

본 연구의 목적은 강원도 양양지역에 분포하는 소나무림을 대상으로 지상부 바이오매스와 수관층 연료특성에 대하여 분석하고자 하였다. 연구대상지는 강원도 양양군 현남면 하월천리 일대 소나무림으로 선정하였으며, 총 13본의 표본목을 벌채하여 분석하였다. 본 연구 결과에 의하면, 양양지역 소나무림의 줄기밀도(g·cm-3)는 0.347~0.409, 지상부 바이오매스 확장계수는 1.251~1.419의 범위로 나타났다. 지상부 연료량은 총 161.6 Mg·ha-1로 나타났으며, 줄기 126.4 Mg·ha-1, 가지 29.3 Mg·ha-1, 잎 5.9 Mg·ha-1로 나타났다. 수관층 연료특성 인자에 관한 연구에서는 수관화 확산 시 연소될 수 있는 연소가능 연료(잎~1 cm이하 가지)의 비율은 45.2%로 나타났고, 연료량을 수관체적으로 나눈 연소가능 연료밀도(kg·m-3)는 평균 0.178로 나타났다. 본 연구의 결과는 소나무림의 바이오매스 및 탄소 흡수량 추정과 수관화 위험성을 연료적 관점에서 평가하는데 있어 유용한 기초자료가 될 것으로 사료된다. The objective of this study was to analyze the above-ground biomass and crown fuel characteristics of Pinus densiflora stands in Yangyang, Gangwon province. A total of thirteen representative trees were destructively sampled in Yangyang region. The results showed that the stem density (g·cm-3) was 0.347~0.409, whereas the above-ground biomass expansion factors ranged from 1.251~1.419. In terms of crown fuel biomass, the above-ground biomass was 161.6 Mg·ha-1 while the stem biomass, branch biomass and needle biomass were 126.4 Mg·ha-1, 29.3 Mg·ha-1 and 5.9 Mg·ha-1, respectively. Needles and twigs with less than 1 cm diameter accounted 45.2% of the total crown fuel load. The available crown bulk density, which was calculated by dividing the crown fuel load to the crown volume, was 0.178 kg·m-3. The results of this study on the biomass and carbon stocks estimation of the Pinus densiflora together with the crown fire hazard assessment based on crown fuel loads are very significant information for the forest managers.

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

갈대 생육지에서 질소 시비가 사초의 생육과 수량 및 사료가치에 미치는 영향

서성,박진길,김원호,김맹중,이상학,정종성,박형수,성하균,이종경,Seo, Sung,Park, Jin Gil,Kim, Won Ho,Kim, Meing Jooung,Lee, Sang Hak,Jung, Jong Sung,Park, Hyung Soo,Sung, Ha Guyn,Lee, Joung Kyong 한국초지조사료학회 2013 한국초지조사료학회지 Vol.33 No.2

본 연구는 질소(N) 시비가 부존 조사료자원인 갈대(Phragmites communis)의 생육과 수량 및 사료가치에 미치는 영향을 구명하고자 2012년에 충남 천안과 경기 안산지역에서 실시되었다. 천안 국립축산과학원 갈대 재배지에서는 N 무시비구, N 50 kg/ha구, N 100 kg구 등 3처리를 두고 4월 30일 시비, 6월 21일 수확하였으며, 안산 시화간척지 갈대 자생지에서는 N 무시비구, N 60 kg/ha구 등 2처리를 두고 5월 1일 시비, 8월 1일 수확하였다. 갈대의 초장과 엽색은 N 시비구에서, 그리고 N 시비수준이 높을 때 양호하였다. 건물률은 N 시비구에서 약간 낮아지는 경향으로 천안지역은 무시비구 39.8%, N 시비구 37.6%, 36.7%, 안산지역은 무시비구 39.4%, N 시비구 37.6%였다. 천안지역의 건물수량, 조단백질 수량 및 가소화 건물수량은 무시비구에서 ha당 각각 4,026 kg, 235 kg, 1,850 kg, N 50 kg 시비구는 각각 4,658 kg, 306 kg, 2,388 kg, N 100 kg 시비구는 각각 5,622 kg, 446 kg, 3,143 kg으로 유의적으로 증가하였으며 (p<0.05), 안산지역은 무시비구에서 각각 2,802 kg, 177 kg, 1,288 kg, N 60 kg 시비구는 각각 3,876 kg, 294 kg, 1,853 kg으로 유의적으로 증가하였다 (p<0.05). 천안지역의 조단백질 함량, 건물 소화율 및 상대사료가치 (RFV)는 무시비구에서 각각 5.85%, 45.96%, 64.0 (품질 5등급), N 50 kg 시비구는 각각 6.58%, 51.27%, 72.3 (5등급), N 100 kg 시비구는 각각 7.94%, 55.91%, 72.7 (5등급)로 높아졌으며, 안산지역도 무시비구에서 각각 6.30%, 45.98%, 70.2 (5등급), N 60 kg 시비구는 각각 7.59%, 47.80%, 78.3 (4등급)으로 높아지는 경향이었다. 이상의 결과를 종합하여 볼 때, 갈대 생육지는 시비가 가능한 조건이라면(하천변이나 강변 등 수질오염이 우려되는 지역이 아닌), ha당 N 60~100 kg을 생육기에 시용해 주는 것이 생산량과 사료가치를 크게 개선시켜줄 수 있어 바람직하였다. This study was carried out to investigate the effect of nitrogen (N) fertilization on the forage growth, production and quality of native reed (Phragmites communis) grasses. Field experiments were conducted in Cheonan and in Ansan, 2012. Treatments were control (no N fertilization), 50 kg/ha and 100 kg/ha in Cheonan plots (fertilization on April $30^{th}$, and harvest on June $21^{st}$). Treatments in Ansan plots were control (no N fertilization) and 60 kg/ha (fertilization on May first, and harvest on August first). Forage growth and leaf colors were improved in N fertilized plots. However, the drymatter (DM) percentage was slightly decreased with N fertilization. Forage yields, in terms of DM, crude protein (CP) and digestible DM (DDM), were significantly increased with N fertilization in both sites. In Cheonan, DM, CP and DDM yields per ha were 4,026 kg, 235 kg and 1,850 kg, respectively, in the control plot, and were 4,658 kg, 306 kg and 2,388 kg, respectively, in the N 50 kg plot, and 5,622 kg, 446 kg and 3,143 kg, respectively, in the N 100 kg plot. In Ansan, DM, CP and DDM yields per ha were 2,802 kg, 177 kg and 1,288 kg, respectively, in the control plot, and were 3,876 kg, 294 kg and 1,853 kg, respectively, in the N 60 kg plot. Forage quality in terms of CP content, in vitro DM digestibility (IVDMD) and relative feed value (RFV) were also increased with N fertilization in both sites. In Cheonan, the CP content, IVDMD and RFV were 5.85%, 45.96% and 64.5 (grade 5), respectively, in the control plot, 6.58%, 51.27% and 72.3 (grade 5), respectively, in the N 50 kg plot, and 7.94%, 55.91% and 72.7 (grade 5), respectively, in the N 100 kg plot. In Ansan, the CP content, IVDMD and RFV were 6.30%, 45.98% and 70.2 (grade 5), respectively, in the control plot, and 7.59%, 47.80% and 78.3 (grade 4), respectively, in the N 60 kg plot. In conclusion, N fertilization of 60~100 kg/ha was desirable for greater forage production, with a higher quality of native Phragmites communis achievable. This should only be applied if the fertilization area is not located at a riverside/streamside or in riparian land where there is a high risk of water pollution by fertilization.

Valuation of ecosystem services in the organic carbon of the Pinus densiflora forest at Mt. Namsan, Seoul Metropolitan City

Lee, Eung-Pill,Lee, Soo-In,Jeong, Heon-Mo,Han, Young-Sub,Lee, Seung-Yeon,Park, Jae-Hoon,Jang, Rae-Ha,Hong, Youg-Sik,Jung, Young-Ho,Kim, Eui-Joo,Lee, Sang-Hun,You, Young-Han The Ecological Society of Korea 2019 Journal of Ecology and Environment Vol.43 No.4

Background: Standing biomass, litter production, rate of litter decomposition, amount of litter on forest floor, and amount of soil organic carbon distribution were investigated from March 2016 to November 2018 in order to evaluate the ecosystem value through organic carbon distribution in the Pinus densiflora forest at Namsan, Seoul Metropolitan City. Results: The amount of organic carbon in the Pinus densiflora forest was 261.09 ton C ha^-1 during the research period, and fixed organic carbon in plant through net photosynthesis was 3.2 ton C ha^-1 year^-1. The organic carbon in plant was 62.77 ton C ha^-1 (24.04%), in litter on the forest floor was 3.65 ton C ha^-1 (1.40%), and in soil was 194.67 ton C ha^-1 (74.56%). The value of plant, litter on forest floor, and soil organic carbon distribution were each 6,277,000 won ha^-1, 365, 000 won ha^-1, and 19,467,000 won ha^-1. The value per ton of fixed organic carbon in plant through net photosynthesis was 320,000 won ha^-1 year^-1 and the value of ecosystem services stored in carbon in the Namsan forest ecosystem was about 26.1 million won ha^-1 for 3 years. Conclusions: The results of this study suggest that the pine forests of Namsan rapidly decompose leaves due to the high atmospheric temperature and accumulate a large amount of organic carbon in the soil to provide climate control regulatory service function.

말초염증에 의한 등족뿌리신경절의 brain-derived neurotrophic factor 합성의 변화

김상열,김정기,김효신,이상지,하선옥,홍해숙,김동선 대한해부학회 1998 Anatomy & Cell Biology Vol.31 No.3

생쥐 중이와 상기도 점막의 섬모세포운동

정하원,오승하,유원석,이강수,모지훈,전상준,김인상,김종선 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.9

Streptozotocin-당뇨병 백서에서 당뇨병 이환기간에 따른 대동맥의 이완능 저하 및 Oxygen-Free Radical에 의한 이완능의 손상정도

김정국,김신우,김수동,서예경,하승우,김보완,백운이,권삼,강승완 경북대학교 병원 1997 경북대학교병원의학연구소논문집 Vol.1 No.1

목적: 당뇨병의 이환기간이 혈관의 내피세포 의존성 및 비의존성 이완능의 저하에 미치는 영향과 이환기간에 따라 oxygen-free radical(OFR)에 의한 동맥이완능의 손상정도에 차이가 있는지를 알아보고자 하였다. 방법: Streptozotocin(STZ)으로 당뇨병이 유도된 3 주 및 10주째의 백서군과 연령이 비슷한 정상 대조백서군의 적출 대동맥환을 norepinephrine으로 수축시킨 상태에서 내피세포 의존성 이완제인 acetylcholine(ACh) 및 비의존성 이완제인 nitroglycerine(NTG)에 대한 이완능을 즉정하여 비교 관찬하였다. 또한 xanthine과 xanthine oxidase의 혼합으로 생성된 H₂O₂에 대동맥환을 노출시킨뒤 역시 ACh과 NTG에 대한 이완능의 손상정도를 비교하였다. 결과: 3주및 10주째 당뇨병 백서의 대동맥환은 모두 대조군 백서의 대동맥환에 비해 ACh에 대한 이완능이 유의하게 감소하였으며 10주째 당뇨병 백서군에서의 ACh에대한 이완능의 저하는 3 주째 당뇨병 백서군에 비해 유의하게 심하였다.H₂O₂에 노출시킨 뒤 ACh에대한 이완능은 3주 및 10주 째 당뇨병 백서군에서 모두 대조군에 비해 유의하게 심한 손상을 보였으나 3주와 10주째 당뇨병 백서군 사이의 손상정도의 차이가 통계학적으로 유의하지는 않았다. 한편 3주 및 10주째 당뇨병 백서군 모두 NTH에 대한 대동맥환의 이완능은 대조 백서군과 별다른 차이가 없었으며 또 H₂O₂에 노출시킨 뒤에도 NTG에 대한 이완능의 손상은 관찰되지 않았다. 결론: STZ-당뇨병백서에서 대동맥의 이완능은 당뇨병에 이환된지 3 주째에 이미 ACh에 대한 내피세포 의존성 이완능이 선택적으로 저하되며 당뇨병의 이환기간이 길수록 이완능의 저하가 심하였고, OFR에 의한 동맥 이완능의 손상도 내피세포 의존성 이완능에만 선택적으로 나타나나 이환기간에 따라 OFR에 의한 이완능 손상정도에는 뚜렷한 차이가 없음을 시사하고 있다. Objectives: Diabetes mellitus produces histological evidence of endothelial as well as changes in vascular function in experimental animal. Oxygen free radicals interfere with of destroy endothelium-dependent relaxation in normal and diabetic blood vessels. The present study was investigated whether the duration of diabetic state can affect the severity of impairment in endothelium-dependent and/or independent relaxation and the sensitivity to oxygen free fadical (OFR)-induced damage in diabetic rat vasculature. Methods: The relaxative responses of aortic ring precontracted with norepinephrine in vitro to cumulative concentrations of acetylcholine (ACh) and nitroglycerine (NTG) were conducted in 3- and 10- week streptozotocin (STZ)-diabetic rats and agematched controls. After exposure to H₂O₂generated by mixing xanthine and xanthine oxidase, the degree of impairment in relaxative responses to ACh and NTG were also compared between 3- and 10-week diabetic rats. Results: The relaxative responses of aortic rings produced by cumulative concentrations of ACh were significantly lower in both 3- and 10-week diabetic rats than in the age-matched controls. The impairments of relaxative responses to ACh in 10-week diabetic rats were significantly greater than those in 3-week ones. After H₂O₂ exposure, the impairments of relaxative responses to ACh in 3- and 10-week diabetic aortas was also significantly greater than those in the control in the control ones. However, the severity of H₂O₂-induced damage in 10-week diabetic aortas was not significantly different than that in 3-week ones. In contrast, aortic rings of 3- and 10-week diabetic rats could still be fully relaxed by NTG, even after exposure to H₂O₂. Conclusion: These findings suggest that in SRZ-diabetic rat aortas selective impairment of endothelium-dependent relaxation to Ach can be found early even over a 3-week period after the induction of diabetes and the impairment may be greater in those with the longer duration of the diabetic state and that the impairment of the vascular relaxation by OFR is also selective to endothelium-dependent response but the sensitivity of OFR-induced damage may not be related to the duration of the diabetic state.

Alendronate의 뼈모세포를 통한 뼈파괴세포 형성 억제 기전

김현진,김민석,김태성,이은주,박하옥,김백윤,김선헌 대한해부학회 2003 Anatomy & Cell Biology Vol.36 No.6