• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.401-405
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• 1999

Comprehensive collecting survey were performed fer study on ovipositioning habits and developmental process of Rana temporaria dybowskii from mid February 1998 to late May 1998 from Kyunggi-do, Kangwon-do and other areas in South Korea. Oviposition occurred in both running water and pool between late February and late May. In lotic habitat, they laid egg mass in irregularly ball shaped, and eggs were sticked to substrates such as stone or macrophytes. On contrary, in the pool, they laid an oval shaped egg mass not sticked to any other substrates. Every egg was hatched at day 7, and all developmental processes were completed at days 71 after oviposition. Developmental process of this species was relatively short, and this may increase predation activities during abundant prey season.

• Restorative Dentistry and Endodontics
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• v.36 no.3
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• pp.188-195
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• 2011

Objectives: The purpose of this study was to evaluate the polymerization shrinkage stress among conventional methacrylate-based composite resins and a silorane-based composite resin. Materials and Methods: The strain gauge method was used for the determination of polymerization shrinkage strain. Specimens were divided by 3 groups according to various composite materials. Filtek Z-250 (3M ESPE) and Filtek P-60 (3M ESPE) were used as a conventional methacrylate-based composites and Filtek P-90 (3M ESPE) was used as a silorane-based composites. Measurements were recorded at each 1 second for the total of 800 seconds including the periods of light application. The results of polymerization shrinkage stress were statistically analyzed using One way ANOVA and Tukey test (p = 0.05). Results: The polymerization shrinkage stress of a silorane-based composite resin was lower than those of conventional methacrylate-based composite resins (p < 0.05). The shrinkage stress between methacrylate-based composite resin groups did not show significant difference (p > 0.05). Conclusions: Within the limitation of this study, silorane-based composites showed lower polymerization shrinkage stress than methacrylate-based composites. We need to investigate more into polymerization shrinkage stress with regard to elastic modulus of silorane-based composites for the precise result.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1093-1097
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• 2006

하천수계는 여러 인자들의 상호작용을 통하여 변화하게 되며, 하천 자정능력에 관한 연구는 이를 중심으로 진행되어 왔다. 여러 환경 요인 중 하상재료는 하천의 조도와 수생태계의 특성을 변화시키게 되며, 유입수의 성상에 따라 수저퇴적물이 쌓이거나, 생물막이 형성되는 매개체 역할을 하게 된다. 특히, 하천의 폭이 좁고 수심이 얕은 개울에서는 하상 퇴적물이 수질에 기여하는 영향이 큰 것으로 알려져 있다. 국내하천의 경우 하상재료가 주로 모래와 자갈이 주를 이루고 있으며, 수심이 낮아 빛의 투과성이 양호하여 부착조류의 증식 및 하상재료(모래 및 자갈 등)를 기질로 한 생물막 형성 등 하상재료는 하천환경의 변화 및 수질변화가 일어나는데 상당한 기여를 하는 것으로 보고되고 있다. 본 연구에서는 하천의 하상재료가 설치된 수로를 이용하여 이화학적요소를 조사, 분석함으로써 하상재료를 통한 수질변화 특성을 비교.검토 하였다. 그 결과 하상재료의 입경이 클수록 DO 변화가 더 큰 폭으로 증가 하였으며, 수위와 유속의 경우 수위가 낮으면서 유속이 적정수준일 경우 DO 증가가 나타나는 것으로 관측되었다. 하천수가 수로에 의해 순환되면서 유기물 저감속도의 측정결과 초기 흡착, 침전 등의 물리적 작용이 부착조류 증식 등의 생물학적 작용보다 우선되면서 입자성 유기탄소(POC)의 제거속도가 용존성 유기탄소(DOC) 의 경우보다 더 빠르고 우선되는 것으로 조사되었다. 영양염류의 경우 부착성조류에 의한 질소 제거능은 실제 질산화작용은 활발히 이루어졌으나 탈질작용에 의한 총질소의 제거는 미비한 것으로 나타났으며, 총인은 입자성유기탄소가 제거되는 것과 유사한 경향을 나타내 제거 기작이 대부분 흡착, 침전에 의한 물리적 자정 작용에 기인한 것으로 조사되었다. 또한 하상재료 입경 변화에 따른 수질변화 특성은 기질(하상재료)의 입경이 작을수록 오염물질의 분해능이 큰 것으로 나타났다. 이와 같이 여러 하천환경 요인 중 하상재료에 의한 하천환경의 다양한 변화는 수질변화 및 자정능력에 큰 영향을 미치게 된다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.43.1-43.1
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• 2010

조직공학의 중요한 요소로 작용하는 scaffold는 여러 가지 필수적인 조건들을 만족시켜야 한다. 대표적인 특징들로는 (1)생분해성 및 비독성, (2)넓은 표면적을 갖는 상호 연결된 내부 다공성 구조, (3)구조적 안정성, (4)세포부착 기질의 제공, (5)낮은 면역 반응성, (6)혈전 형성 억제, (7)친수성, (8)생체 기능성 등을 들 수 있다. 이러한 scaffold가 갖추어야 할 특성 중에서 세포 부착 기질 제공을 위하여 scaffold에 표면 개질을 통한 기능기를 도입하였다. 본 연구에서는 BCP scaffold의 구조적 안정성 부여를 위하여 PCL(polycaprolactone)을 infiltration 하였다. PCL은 소수성의 특징을 갖고 있어 세포와 상호작용 할 수 있는 생물학적 반응기가 없기 때문에 세포와의 친화성이 떨어진다. 세포의 친화성을 높여주기 위해 실리콘의 전구체인 TEOS(tetraethly orthosilicate)를 코팅하고, 그 위에 카복실기(carboxylic acid group)를 도입하였다. 또한 세포의 고정화를 높여주기 위해 fibronectin을 코팅하여 BCP/PCL scaffold의 세포 친화성을 높여주었다. 이와 같이 제조된 고기능성 BCP/PCL scaffold의 내부 구조와 특성을 Micro-CT로 확인하였고, 또한 실리콘 코팅 여부를 확인하기 위하여 SEM-EDS를 통해 관찰하였으며, FT-IR 관찰을 통해 카복실기 도입 여부를 확인 하였다. 또한 생체적합성 평가를 위해 MTT assay, 조골세포의 부착에 미치는 영향을 관찰하기 위해 SEM, 조골세포의 유전자 발현에 미치는 영향을 관찰하기 위해 RT-PCR을 통해 확인 하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.608-613
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• 2002

Experimental transplantation of Eklonia stoionifera to natural rock was carried out using adhesive Blue. A plant was attached to an architecture tile ($10\times$10 cm) with the glue, and then the tile was attached to natural rock with underwater glue. Within one month, the tile were fixed to natural rock with an attachment rate of $75\%$, and 5. stoionifera grew up with an insertion rate of $66.7\%$ on the tile. After two months, number of E. stolonifera on the tile decreased. However, the attached plants were regenerated by new stolons, maintaining good growing condition. After seven months,5. stoloaifera increased 6 to 71 individuals. These results indicate that regeneration of plants was mainly affected by the recruitment of stolen around the plant.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.136-143
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• 1999

To understand the growth of attached microalgae to the immersed artificial surfaces in seawater with exposure time, chlorophyll a (chl a) concentration and abundance of attached microalgae to glass slides, and primary productivity and chl a concentration on coverglasses were investigated in Incheon Harbour in May, June 1996 and January-February 1997. Chl a concentrations of microalgae and abundances of diatoms attached to glass slides reached 62.5 mg chl a $m^{-2}$ and $144{\times}10^3$ cells $cm^{-2}$, respectively, during the study period. Chl a concentrations increased with exposure time, and they were significantly correlated with the abundances of attached diatoms ($r^2=0.79$, p<0.001). The chl a concentrations of attached micro algae on coverglass reached the maximum values of 31.1 mg chl a $m^{-2}$ and 65.4 mg chl a $m^{-2}$, and then decreased in May, June 1996. But in January-February 1997, the chl a concentration increased continuously up to 98.9 mg chl a $m^{-2}$. The primary productivity reached the maximum values of 63.1 mgC $m^{-2}\;h^{-1}$, 347.0 mgC $m^{-2}\;h^{-1}$ and 78.3 mgC $m^{-2}\;h^{-1}$, respectively, in May, June and January-February. The primary productivity in May and June varied in accordance with chl a concentrations. But in January-February, the primary productivity decreased from 26 days of exposure while chl a concentration continued to increase. Two cases that primary productivity decreased abruptly seemed to be caused by decrement of chl a and light specific $P^B$ (chl a specific primary productivity) (May and June) and by decrement of light specific $P^B$ due to photoinhibition (January-February). The results of present study indicated that chl a concentrations and the primary productivity of microalgae attached to artifical surfaces immersed in seawater would expedite analysis of dynamics of biomass and physiological status of attached microalgae during biofilm formations.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1161-1169
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• 2008

The removals of TCE and PCE vapor with or without a supply of toluene as a primary substrate were compared in a biofiltration process, and the variations of microbial communities associated with the removal were also investigated. As a result of investigations on the removals of TCE/PCE in a biofilter B within which TCE/PCE-acclimated sludge was attached on the surface of media without a supply of primary substrate, and those in another biofilter A where toluene-acclimated sludge was attached with a supply of toluene as a primary substrate, followings were found: (i) parts of microbes responsible to the decomposition of toluene vapor participate in the removal of chlorinated VOCs such as TCE and PCE, and (ii) effective biological removals of TCE and PCE vapor do not necessarily need cometabolism. Sequencing of 16S rDNA obtained from the band profile of DGGE (Denaturating Gradient Gel Electrophoresis), it was confirmed that: (i) uncultured alpha proteobacterium, uncultured Desulfitobacterium, uncultured Rhodobacteraceae bacterium, Cupriavidus necator, and Pseudomonas putida were found to be toluene-decomposing microbes, (ii) alpha proteobacterium HTCC396 is a TCE-removing microbe, (iii) Desulfitobacterium sp. is a PCE-decomposing microbe, and (iv) particularly, uncultured Desulfitobacterium sp. is probably a microbe decomposable not only toluene but also various chlorinated VOC vapor including TCE and PCE.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.4
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• pp.184-191
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• 2010

Epiphytic diatoms are very important organisms in the seagrass ecosystem because their colonization on leaves increases microtopography and provides attachment sites that make the leaves more hospitable for other epiphytes. Epiphytic diatoms were attached to the leaves in the following 3 manners: (1) parallel to the cells of the seagrass leaf or by molding the shape of the diatom along the cell shape of the leaf; (2) with increasing diatom density toward the leaf tip; (3) Cocconeis species as attaching species than the Naviculoid species as the second attaching species on the leaf tip. In addition, the epiphytic diatom communities on Zostera marina leaves differed from those on the Zostera japonica leaves, but were very similar to the epiphytic communities on Zostera caespitosa leaves. Our results suggest that the epiphytic community on seagrass leaves varied according to the leaf shape such as leaf length and width, but the leaf cell shape or size did not influence the dynamics of the diatom communities.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.95-104
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• 1999

Comparative biodegradation studies of liquid and solid alkanes and of two different solid alkanes were conducted by an isolated Acinetobacter sp., which degraded crude oil alkanes simultaneously. for the determination of degradation mechanism of hydrophobic crude oil constituents. Also a model oil experimental system composed of a solid alkane. heneicosane, as a substrate and a non-degradable non-aqueous phase liquid. pristane, as an oil matrix was established and studied. It was proposed that the Acinefobacter sp. utilized hydrophobic substrates directly on the surface of them with no difference in the degradation rates between the liquid and solid alkanes. On the basis of the results from the heneicosane/pristane system which imitates crude oil matrix containing solid constituents. the crude oil matrix was considered to reduce the bioavailability of contained substrates by reducing the specific surface area of substrates to contact with microorganisms.

• Journal of Practical Agriculture & Fisheries Research
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• v.3 no.1
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• pp.132-141
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• 2001

This study was conducted to determine effects of whole and processed corns on attachment characteristics of rumen microbes in Hanwoo. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). After each processed corns was incubated in the rumen of Hanwoo for 12 h and 24 h, attachment characteristics of rumen microbes and morphological changes of feed substrates was examined by utilizing scanning electron microscopy(SEM). In this study, the treatment group of GC and CC showed the highest in the attachment of rumen microbes. On the other hand, microbial attachments to the starch particle of WC and SC were hardly detected. However, with the increase of incubation time the surface of WC and SC was covered by many microbes, resulting in enhancing the surface degradation.