• 생명과학회지
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• 제25권8호
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• pp.910-916
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• 2015

최근 식물 성장에 있어 곰팡이 독소에 관련된 질병에 효과가 있는 Bacillus mojavensis 균주 사용의 보고가 있다. 우리는 B. mojavensis KJS-3균주의 다양한 온도, 염도, 에탄올, pH에서 성장하는 특징을 확인 하였다. B. mojavensis KJS-3균주는 Polymerase chain reaction 분석에 의해 fengycin을 LC-MS/MS 분석을 통해서는 iturin 및 surfactin 와 같은 cyclic lipopeptides를 생산함을 확인 하였다. B. mojavensis KJS-3균주는 식물 유해 곰팡이 균주인 Botrytis cinerea, Rhizoctonia solani AG-4, Sclerotinia sclerotiorum, Colletotricum goeosporioides에 항곰팡이 효과가 있음을 확인하였고 이 결과를 바탕으로 인삼재배에 있어 B. mojavensis KJS-3를 사용하여 성장을 관찰한 결과 뿌리 내에서 성장하여 plant growth promoting endophyte가 있음을 알 수 있었다. 이러한 특징들에 의해 미생물 농약 및 비료로 사용할 수 있을 것이다.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.974-978
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• 2012

The effect of Cu coating on the sensing properties of nano $SnO_2:Cu$ based sensors for the $CH_4$, $CH_3CH_2CH_3$ gas was studied. This work was focussed on investigating the change of sensitivity of nano $SnO_2:Cu$ based sensors for $CH_4$, $CH_3CH_2CH_3$ gas by Cu coating. Nano sized $SnO_2$ powders were prepared by solution reduction method using stannous chloride($SnCl_2{\cdot}2H_2O$), hydrazine($N_2H_2$) and NaOH and subsequent heat treatment. XRD patterns showed that nano $SnO_2$ powders with rutile structure were grown with (110), (101), (211) dominant peak. The particle size of nano $SnO_2:Cu$ powders at 8 wt% Cu was about 50 nm. $SnO_2$ particles were found to contain many pores, according to SEM analysis. The sensitivity of nano $SnO_2:Cu$ based sensors was measured for 5 ppm $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air with that in target gases. The sensitivity for both $CH_4$ and $CH_3CH_2CH_3$ gases was improved by Cu coating on the nano $SnO_2$ surface. The response time and recovery time of the $SnO_2:Cu$ gas sensors for the $CH_4$ and $CH_3CH_2CH_3$ gases were 18~20 seconds, and 13~15 seconds, respectively.

• 원예과학기술지
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• 제34권4호
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• pp.564-577
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• 2016

Salinity stress limits plant cultivation in many areas worldwide; however, persimmon (Diospyros spp.) has high tolerance to salt. Five accessions of Diospyros [three of Diospyros lotus (accession numbers 824, 846, and 847); one of Diospyros kaki var. sylvestris (869); and one of Diospyros virginiana (844)] were chosen for analysis of salinity stress. We compared the effects of salt stress on plant growth, relative water content (RWC), malondialdehyde (MDA), electrolyte leakage (EL), hydrogen peroxide content ($H_2O_2$), and antioxidative enzyme activities (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD; and ascorbate peroxidase, APX) in leaves of healthy potted seedlings from each of the five accessions after salt treatment for 25 days. Salt stress affected the growth of plants in all five accessions, with all three D. lotus accessions showing the most severe effect. Salt stress increased membrane lipid peroxidation in all accessions, but a stronger increase was observed in the three D. lotus accessions. Moreover, accumulation of $H_2O_2$ was faster in salt-sensitive D. lotus compared to salt-tolerant D. virginiana 844. The activities of all antioxidant enzymes increased in D. virginiana 844 and in D. kaki var. sylvestris 869; the activities of SOD, CAT, and APX were at similar levels in D. virginiana 844 and D. kaki var. sylvestris 869, but POD activity was stimulated to a greater extent in D. virginiana 844. The activities of all antioxidant enzymes (except POD) decreased in D. lotus 824 and increased (except for SOD) in D.lotus 846. The activities of SOD and APX decreased in D. lotus 847, whereas POD and CAT activities both increased. Relative water content decreased significantly in D. lotus. No significant changes in lipid peroxidation or relevant antioxidant parameters were detected in any of the accessions in controls treated with 0.0% NaCl. D. virginiana 844 had higher antioxidant capacity in response to salinity compared to other persimmon rootstocks. These results indicate that changes of these key physiological variables are related to salinity resistance in different accessions of persimmon.

• Journal of Forest and Environmental Science
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• 제30권2호
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• pp.243-252
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• 2014

Forest tree species usually takes for long periods to be harvested and cultivated but spearmints are a good model system for woody plant because of reducing and shortening cultivation time. Spearmints are good model plants (Mentha species) for research about terpenoids production and industrial essential oil manufacture. Isopentenyl pyrophosphate isomerase (Iso) and limonene synthase (Limo) are the key enzymes of terpenoid biosynthesis pathway. Transgenic and wild spearmints (Mentha spicata, MS) were cultured in vitro and assessed for the essential oil contents. The content of essential oil of transgenic spearmint also was enhanced slightly depending on the target terpenoid genes. In an attempt to increase productivity of terpenoids further, salt and fungal elicitation strategy was adopted on transgenic Mentha spicata. The salt (800 mM NaCl) as abiotic and two fungi (Botrytis cinerea and Glomerella cingulata) as biotic were used for elicitors. In the absence of salt stress four terpenoids were detected from the spearmint extracts, all of them being monoterpenes. On the other hand, the transgenic (MSIso) extracts contained eleven terpenoids (10 monoterpenes and 1 phenylpropene) while transgenic (MSLimo) extracts contained seven monoterpenes. After 3 days of fungal infection, the resistance indices further increased to 4.38, 3.89 and 2.04 for wild type, MSIso and MSLimo, respectively. The salt and fungal elicitators proved beneficial towards modifying both the terpenoids profile and improvement in the composition of essential oil. These results have important applications for the large-scale production of essential oils and forest biotechnology with respect to spearmint.

• 한국환경과학회지
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• 제25권6호
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• pp.789-798
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• 2016

Lactic acid bacteria (LAB) are industrially important microorganisms for probiotics. The recent widespread application of LAB for preparation of functional food is attributable to the accumulating scientific evidence showing their beneficial effects on human health. In this study, we isolated and characterized plant-derived LAB that show angiotensin-converting enzyme (ACE) inhibitory and antioxidant activities. The selected strain K2 was isolated from Kimchi, and identified as Lactobacillus plantarum by 16S rRNA gene analysis. The strain grew under static and shaking culture systems. They were also able to grow in different culture conditions like $25^{\circ}C{\sim}37^{\circ}C$ temperature, 4~10 pH range and ~6% NaCl concentration. L. plantarum K2 was highly resistant to acid stress; survival rate of the strain at pH 2.5 and 3 were 80% and 91.6%, respectively. The strain K2 also showed high bile resistance to 0.3% bile bovine and 0.3% bile extract with more than 74% of survival rate. The cell grown on MRS agar plate containing bile extract formed opaque precipitate zones around the colonies, indicating they have bile salt hydrolase activity. The strain showed an inhibitory activity against pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Listeria monocytogenes; antibacterial activity was probably due to the lactic acid. The K2 strain showed relatively higher autoaggregation values, antihypertensive and antioxidant activities. These results suggest that L. plantarum K2 could be not only applied as a pharmabiotic for human health but also is also starter culture applicable to fermentative products.

• 한국표면공학회지
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• 제41권6호
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• pp.292-300
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• 2008

Dental implant system is composed of abutment, abutment screw and implant fixture connected with screw. The problems of loosening/tightening and stability of abutment screw depend on surface characteristics, like a surface roughness, coating materials and friction resistance and so on. For this reason, surface treatment of abutment screw has been remained research problem in prosthodontics. The purpose of this study was to investigate the stability of TiN and WC coated dental abutment screw, abutment screw was used, respectively, for experiment. For improving the surface characteristics, TiN and WC film coating was carried out on the abutment screw using EB-PVD and sputtering, respectively. In order to observe the coating surface of abutment screw, surfaces of specimens were characterized, using field emission scanning electron microscope(FE-SEM) and energy dispersive x-ray spectroscopy(EDS). The stability of TiN and WC coated abutment screw was evaluated by potentiodynamic, and cyclic potentiodynamic polarization method in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The corrosion potential of TiN coated specimen was higher than those of WC coated and non-coated abutment screw. Whereas, corrosion current density of TiN coated screws was lower than those of WC coated and non-coated abutment screw. The stability of screw decreased as following order; TiN coating, WC coating and non-coated screw. The pitting potentials of TiN and WC coated specimens were higher than that of non-coated abutment screw, but repassivation potential of WC coated specimen was lower than those of TiN coated and non-coated abutment screws due to breakdown of coated film. The degree of local ion dissolution on the surface increased in the order of TiN coated, non-coated and WC coated screws.

• 한국어병학회지
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• 제7권1호
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• pp.23-36
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• 1994

최근 7월부터 9월사이 고수온기에 경남일대의 육상수조식 넙치양식장에서 8균주의 Staphylococcus epidermidis를 분리하여 이들의 생물학적 및 생화학적 특성을 알아보았다. 분리균주는 BHIA, HIA, Staphylococcus No. 110 및 ETGP에서 잘 발육하였으며, 식염농도 2.0~3.0%, $30^{\circ}C$ 전후 그리고 pH는 7.0 전후에서 발육상태가 좋았다. 또한 DNase, coagulase에는 전 균주가 음성이었으며, 용혈성은 FSJ-2균주만이 약한 음성을 나타내었고, ureas 양성, novobiocin 저항성에는 음성을 나타내었다. 탄수화물의 분해능에서 전 균주는 가스를 생산하지 않았고 혐기적 조건하에서 포도당과 maltose를 분해하였으며 mannitol은 FSJ-19균주만이 약하게 분해한 것을 제외하고는 전 균주가 음성이었다. 호기적 조건하에서 전 균주는 포도당, fructose, galactose, sucrose, maltose 및 dextrin을 분해하였다. 분리균주의 임상적인 주요 특성에서 8개의 균주는 4가지의 다른 biotype code를 나타내었으며, 약제 감수성 그룹에서도 4가지의 다른 패턴을 나타내었다. 이상의 결과는 Bergey's manual of systematic bacteriology에 기재된 S. epidermidis의 coagulase, urease, DNase, $\beta$-galactosidase, novobiocin 저항성 및 포도당의 혐기적 분해성과 잘 일치하였고, 또한 Mickelsen et al.(1985)이 기재한 biotype과 약재 감수성 패턴이 잘 일치하여 본 분리균을 S. epidermidis로 동정하였다.

• 한국표면공학회지
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• 제34권2호
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• pp.105-114
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• 2001

$Al_2$$O_3$ coatings were deposited on M2 high speed steels by the plasma enhanced chemical vapor deposition (PECVD) process, using a gas mixture of AlC1$_3$, $H_2$, $CO_2$ and Ar $Al_2$$O_3$ coatings had interference color and showed amorphous phase. $A1_2$X$A1_3$/($Ti_{0.5}$ /$Al_{0.5}$ )N double layer coatings were produced in the sequence of substrate $NH_3$ plasma pretreatment, ($Ti_{0.5}$$Al_{0.5}$)N depoition process, $Al_2$$O_3$ deposition process. $Al_2$ $O_3$/( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings showed NaCl structure in ( $Ti_{0.5}$A $l_{0.5}$)N layer and amorphous phase in A1$_2$ $O_3$ layer. It was shown that $Al_2$ $O_3$ columns continuously grew onto ( $Ti_{0.5}$A $l_{0.5}$)N columns. ( $Ti_{0.5}$A $l_{0.5}$)N single coating and $Al_2$ $O_3$/( $Ti_{0.5}$A $l_{0.5}$)N double layer coating were oxidized at $700^{\circ}C$, 80$0^{\circ}C$, 90$0^{\circ}C$ for 1hr, 3hr in atmosphere. At 80$0^{\circ}C$, single layer coatings were oxidized, which were examined substrate oxide particle. But $Al_2$ $O_3$/ ( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings maintained the asdeposited state. Therefore, $Al_2$ $O_3$/ ( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings have moreexcellent oxidation resistance than ( $Ti_{0.5}$A $l_{0.5}$)N single layer coatings.X> 0.5/)N single layer coatings.s.

• 한국구조물진단유지관리공학회 논문집
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• 제26권6호
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• pp.1-13
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• 2022

이 연구에서는 콘크리트 표면에서 측정된 반전지전위(half-cell potential, HCP)값을 활용하여 철근 부식 상태 및 부식속도의 정량적 평가 가능성을 논의하였다. 이 연구에서는 염수에 침지된 콘크리트 속 철근에 전류를 인가하여 다양한 부식상태의 철근 콘크리트 실험체(한 변의 길이가 200mm 인 정육면체)를 준비하였다. 부식촉진시험을 마치고, 염수 포화상태의 콘크리트 실험체 표면에서 HCP값을 측정하였고, 바로 이어서 동일한 조건의 실험체에서 전기화학적 임피던스 분광법을 활용하여 콘크리트 속 철근의 분극저항값을 측정하였다. 측정된 분극저항값을 Stern-Geary식에 대입하여 부식전류밀도(corrosion current density, i_corr)를 계산하였다. 실험결과를 바탕으로 염해에 따라 다양한 부식상태의 철근이 매입된 철근 콘크리트 실험체의 염수 포화상태에서 HCP와 i_corr의 상관관계를 도출하였다. 대체적으로 HCP와 i_corr은 로그선형관계를 보였으며, R2값이 0.87이상의 높은 적합도를 확인하여 통계적인 유의함을 확인하였다. 이러한 결과는 일정한 환경에 노출된 철근 콘크리트일 경우 자연전위값을 측정함으로서 철근의 부식상태 및 속도를 평가할 수 있음을 실험적으로 확인하였다.

• 한국어병학회지
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• 제10권1호
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• pp.1-14
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• 1997

양식 농어 치어에 발생하는 포도상구균증의 원인균에 대한 생화학적 성상, 생물학적 성상, 약제 감수성 및 병원성을 검토하였다. 병어의 간, 신장, 비장 및 뇌로부터 원인균을 분리하였으며, 생물학적 생화학적 성상을 조사한 결과 본 균을 Staphylococcus epidermidis로 동정하였다. S. epidermidis에 감염된 농어 치어의 외부 소견은 안구 충혈 및 백탁이 주증상이었고, 해부학적 소견은 뇌출혈, 간울혈, 신장 및 비장의 팽대가 특징적였다. 분리균주는 BHIA, HIA 및 Staphylococcus No. 110에서 잘 발육하였으며, 식염 농도 0~9% (최적 염분 : 1~3%), $10\sim45^{\circ}C$(최적 온도 ; $35\sim40^{\circ}C$) 및 pH 4~10(최적 pH : 8)에서 발육하였다. DNase, coagulase에는 모든 균주가 음성였으며, 용혈성은 양성을 나타내었고, urease 양성, novobiocin 저항성에는 음성을 나타내었다. 모든 균주는 탄수화물 분해시 가스를 생성하지 않았고 혐기적 조건하에서 포도당과 maltose를 분해했다. 호기적 조건하에서 모든 균주는 포도당, galactose, sucrose, maltose 및 dextrin을 분해하였다. $1.7{\times}10^{10}$ viable cells/$m\ell$를 근육 주사한 실험구에서는 모든 접종어에 강한 병원성을 나타내었으나, $1.7{\times}10^4$ viable cells/$m\ell$를 접종한 실험구에서는 약한 병원성이 나타났다. 분리균은 bacitracin, erythromycin, norfloxacin 등에 감수성을 나타냈으나, colistin, gentamicin, nalidixic acid 등에는 내성을 나타냈다. 병어의 병리조직학적 관찰 결과 뇌의 소상 울혈, 간 실질세포의 퇴행성 병변 및 신장 조직에서 뇨세관 상피세포의 분리와 괴사가 나타났다.