• Asian Journal of Atmospheric Environment
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• 제12권1호
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• pp.67-77
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• 2018

To investigate the effects of forest and the surrounding natural and anthropogenic sources on the bulk depositions on forested land, this study examined differences in ion concentrations between wet-only and bulk samples at two forested sites in Japan. The surrounding natural and anthropogenic sources at each site were different; Shirasaka is in a rural area and Tanashi is an urban environment. The volume weighted (vw) mean concentrations of $K^+$ and $Ca^{2+}$ in the bulk samples were significantly (p<0.05) higher than those in the wet-only samples at both sites. The forest canopy and a nearby incineration plant were hypothesized to be the main sources of $K^+$ contaminants at Shirasaka and Tanashi, respectively. The transport of sea salt and urban dust may explain the presence of enriched $Ca^{2+}$ concentrations in the bulk samples at Shirasaka and Tanashi, respectively. The $NH_4{^+}$ concentrations in the Shirasaka bulk samples were significantly (p<0.05) lower than those in the wet-only samples. The vw mean $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations in both sample types were not significantly different at either site. This study demonstrated that the ion concentration differences between wet-only and bulk samples were affected by nearby natural and anthropogenic sources even at forest sites, similar to previous findings for non-forested locations. However, the $K^+$ concentration differences between wet-only and bulk samples may be higher owing to forest sources, even in the absence of anthropogenic sources.

• Preventive Nutrition and Food Science
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• 제9권2호
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• pp.150-155
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• 2004

The free radical scavenging activities and the protective effects of Rhus javanica extracts against oxidative damage induced by reactive oxygen species (ROS) were investigated. n-Hexane, ethyl acetate and water fractions were prepared from a methanol extract. DPPH radical, superoxide anion and hydroxyl radical scavenging activities were estimated. Intracellular ROS formation was quantified using fluorescent probes, 2', 7'-dichlorofluorescin diacetate (DCFH-DA) for hydroxyl radical and dihydroethidium (DHE) for superoxide anion. The oxidative DNA damage was investigated by the comet assay in HepG$_2$ cells exposed either to $H_2O$$_2$ or to menadione. The highest $IC_{50}$/ values for DPPH radical scavenging activity was found in the ethyl acetate fraction with a value of 5.38 $\mu\textrm{g}$/mL. Cells pretreated with $\geq$ 1 $\mu\textrm{g}$/mL of the ethyl acetate extract had significantly increased cell viability compared to control cells, which were not pretreated with the extract. Intracellular ROS formation and DNA damage in HepG$_2$ cells, which were pretreated with the various concentrations of Rhus javanica ethyl acetate extract and then incubated either with $H_2O$$_2$ or with menadione, reduced in a dose-dependent manner. These findings suggest that Rhus javanica might have biologically active components which have strong protective effects against ROS induced oxidative damages to the biomolecules, such as cell membranes and DNA.

• 한국균학회지
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• 제28권1호
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• pp.26-31
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• 2000

팽이버섯의 자실체형성 과정에 특이적으로 발현하는 FVFD16과 FVFD30 유전자의 genomic 클론을 단리하여 염기서열을 분석하였다. FVFD16은 Open Reading Frame(ORF)내에 2개의 intron이 관찰되었고, FVFD30 유전자에서는 4개의 intron이 관찰되었다. 또한 intron의 특징적인 염기서열인 GT/AG의 rule과도 일치하고 있음이 밝혀졌다. FVFD16과 FVFD30의 두 유전자 모두에서 진핵생물의 promoter영역에서 자주 관찰되는 CAAT box와 유사한 배열과 TATA box가 존재했다. 또한, 전사개시점의 바로 앞에서 관찰되어지는 CT-rich의 영역이 존재하고 있었으며, 특히 FVFD30에서는 전사개시 시에 중요한 역할을 할 것으로 예상되는 CCACC의 서열이 관찰되었다. 한편 FVFD16 genomic클론의 염기서열 분석결과 cDNA클론과 80%의 상동성을 나타내는 gene family임이 밝혀졌다. 여러 가지 제한효소에 의한 genomic southern blot 분석결과 FVFD16과 FVFD30은 2번 이상의 반복배열 또는 gene family의 존재가 확인되었다.

• Journal of the Korean Wood Science and Technology
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• 제28권1호
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• pp.36-41
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• 2000

목재는 2-메타크릴로일옥시에틸 이소시아네이트(MOI)와 $50-60^{\circ}C$에서 촉매존재하에서 매우 쉽게 반응하였다. 적외선 분광분석을 통하여, 목재가 MOI와 우레탄결합($1715cm^{-1}$)를 형성하고 있을 뿐만 아니라, 올레핀구조의 탄소간 이중결합 ($1635cm^{-1}$)이 존재하고 있음이 밝혀졌다. 도입된 메타크릴산기는 다른 비닐모노머와의 그래프트공중합시 반응시점으로 작용할 것이다. 또한 MOI처리목재는, MOI와의 반응에 의해 친수성이던 목재의 표면이 소수화되어 접촉각이 증대되는 결과를 낳았다. X선광전자분광분석(XPS)의 결과, 목재의 표면부위의 대부분은 MOI에 의해 개질되었음을 밝혀졌다.

• Journal of the Korean Wood Science and Technology
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• 제26권3호
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• pp.53-62
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• 1998

In this research, 7 species of white rot fungi were used for determining the resistance against pentachlorophenol (PCP). Three fungi with good PCP resistance were selected for evaluating the biodegradability, and biodegradation mechanism by HPLC and GC/MS spectrometry. Among 7 fungi, there were significant differences on PCP resistance on 4 different PCP concentrations. In the concentrations of 50 and 100ppm ($\mu$g of PCP per g of 2% malt extract agar), most fungi were easily able to grow, and well suited to newly PCP-added condition, but in that of more than 250ppm, the mycelia growths of Ganoderma lucidum 20435, G. lucidum 20432, Pleurotus ostreatus, and Daldinia concentrica were significantly inhibited or even stopped by the addition of PCP to the culture. However, Trametes versicolor, Phanerochaete chrysosporium, and Inonotus cuticularis still kept growing at 250ppm, indicating the potential utilization of wood rot fungi to high concentrated PCP biodegradation. Particularly, P. chrysosporium even showed very rapid growth rate at more than 500ppm of PCP concentration. Three selected fungi based on the above results showed an excellent biodegradability against PCP. P. chrysosporium degraded PCP up to 84% on the first day of incubation, and during 7 days, most of added PCP were degraded. T. versicolor also showed more than 90% of biodegradability at 7th day, and even though the initial stage of degradation was very slow, I. cuticularis has been approached to 90% at 21 st day after incubation with dense growing pattern of mycelia. Therefore, the PCP biodegradability was definitely dependent on the rapid suitability of fungi to newly PCP-added condition. In addition, the PCP biodegradation by filtrates of P. chrysosporium, T. versicolor, and I. cuticularis was very minimal or limited, suggesting that the extracellular enzyme system may be not so significantly related to the PCP biodegradation. Among the biodegradation metabolites of PCP, the most abundant one was pentachloroanisole which resulted in a little weaker toxicity than PCP, and others were tetrachlorophenol, tetrachloro-hydroquinone, benzoic acid, and salicylic acid, suggesting that PCP may be biodegraded by several sequential reactions such as methylation, radical-induced oxidation, dechlorination, and hydroxylation.

• Journal of the Korean Wood Science and Technology
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• 제26권3호
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• pp.63-72
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• 1998

In order to evaluate the biodegradability and mechanism of 4,5,6-trichloroguaiacol (TCG) produced from bleaching process in pulp mill by Phanerochaete chrysosporium, Trametes versicolor, and Inonotus cuticularis, changes in TCG and its metabolites during biodegradation were analyzed by HPLC, and GC/MS spectrometry. By three fungi, the maximum biodegradability against TCG were very quickly reached, compared with other chlorinated aromatic compounds such as PCP. Within 24 hrs, T versicolor indicated up to 95% of TCG removal rate, and P. chrysosporium and I. cuticularis also showed more than 80%, and 90%, respectively. Particularly, in case of T. versicolor, the removal rate of TCG after 1 hr. incubation was reached to approximately 90%, implying very rapid metabolization of TCG. However, by analyzing the filtrates extracted from TCG containing culture by GC/MS, the major metabolites at initial stage of biodegradation were dimers, indicating that the added TCG monomers were quickly polymerized. The others were trichloroveratrole, dichloroguaiacol, and trichlorobenzoic acid, suggesting that TCG may be biodegraded by several sequential reactions such as polymerization, oxidation, methylation, dechlorination, and hydroxylation. In other experiments, the extracellular fluid which did not contain any fungal mycelia was used to evaluate the effect of mycelia on TCG biodegradation. The extracellular fluid of T. versicolor also biodegraded TCG up to 90% within 24hrs, but those of P. chrysosporium and I. cuticularis did not show any good biodegradability. T versicolor showed the highest value of laccase, and other two fungi indicated a little activity of lignin peroxidase (LiP) and manganese peroxidase (MnP). In addition, the laccase activity of T. versicolor was very linearly proportional to the removal rate of TCG during incubation, in other words, showing the induction effect against TCG. Consequently, the biodegradation of TCG was very dependent upon the activity of laccase.

• Journal of the Korean Wood Science and Technology
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• 제38권6호
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• pp.490-497
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• 2010

국내산 밤나무 목재의 효율적 이용을 위한 기초 자료를 얻기 위하여 밤나무 7품종(단택, 이취, 이평, 만성, 은기, 유마, 축파)의 목섬유 및 도관요소 길이를 대상으로 방사방향 변이성을 조사하였다. 목섬유 및 도관요소 길이는 조재와 만재 부위를 구별하여 3연륜 간격으로 광학현미경과 화상분석기를 사용하여 측정하였다. 밤나무 수간에 있어 만재 목섬유의 길이가 조재의 것보다 다소 더 길었으며, 조재 및 만재 모두에 있어 연륜 증가에 따라 목섬유 길이가 증가하는 경향이 나타났다. 이와 유사하게, 만재 도관요소의 길이 역시 조재의 것보다 다소 더 길었으며, 조재 및 만재 모두에 있어 연륜 증가에 따라 도관요소의 길이가 완만하게 증가하는 경향을 보였다. 결론적으로 밤나무 수간에 있어서의 목섬유 및 도관요소의 길이는 성숙재와 미성숙재를 판단하는 재질 지표로 이용될 수 있을 것으로 생각된다

• 임산에너지
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• 제22권2호
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• pp.26-35
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• 2003

Bamboo strand board (BSB) was made with Phyllostachys banbusoides growing in Damyang district. Physical and mechanical properties of this BSB were summarized as follows; The specific gravity of BSB was 0.63∼0.79. Specific gravity decreased slightly with the thickness and length of BSB. Moisture content of BSB manufactured was 5.8∼6.9%. The absorption ate of BSB (42∼48%) did not show any relationship with the thickness and length of BSB. The thickness swelling rate of BSB was 13.9∼17.0%, relatively higher than any other panel products. Thickness swelling rate increased with the thickness of BSB, showing the strand thickness influenced much more on the rate of thickness swelling of BSB than the length of strand. The 3-point bending strength of BSB was 98∼126kgf/$\textrm{cm}^2$. Bending strength of showed the tendency of increase with the increased length of BSB, but with the decreased thickness. In particular, the length of BSB showed more effect on the increase of bending strength of BSB than the thickness of BSB. The compression strength perpendicular to BSB surface was 411 ∼ 465 kgf/$\textrm{cm}^2$, and the optimal length of strand for the 1mm- and 2mm-thickness of strand was 40mm and 60mm, respectively. Compression strength paralleled to BSD was 160∼221kgf/$\textrm{cm}^2$ and the optimal length of strand for the 2mm-thickness of strand appeared to be 60mm. The present work showed that appearance, physical and mechanical strength of BSB appeared quite positive in terms of board qualities, suggesting that bamboo would be appropriate for the production of board materials. In addition, our work showed that the crucial factor for determining the mechanical characteristics of BSB was the dimension of strand.

• 임산에너지
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• 제22권2호
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• pp.60-68
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• 2003

목재의 기계적 특성을 평가하기 위하여 여러 가지 비파괴 측정 기술이 도입되고 있다. 본 실험은 낙엽송(Larix kaempferi Carr.) 소경재 원목을 초음파의 통과 속도와 종진동의 고유진동수를 이용한 비파괴 측정 기술로 영계수를 측정하여 휨강도 실험을 통해 얻은 실측 영계수와 휨파괴계수의 상관관계를 검토하였다. 실험에는 50본의 소경재 원목이 사용되었다. 종진동의 고유진동수를 이용한 영계수와 실측 영계수는 비교적 높은 상관관계를 나타내었다. 초음파를 이용한 비파괴 영계수 측정은 옹이의 출현빈도가 높은 원목의 선별에 효과적이었으며 종진동의 고유진동수를 이용한 측정은 할렬의 출현빈도가 높은 원목의 선별에 효과적임을 확인하였다.

• 한국농림기상학회지
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• 제11권4호
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• pp.247-251
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• 2009

강우가 토양 호흡에 미치는 영향을 평가하기 위해, 일본 서부에 위치한 활엽수림에서 2001년 2월 20일부터 11월 19일까지 강우를 차단한 상태에서 토양 $CO_2$ 플럭스를 측정하였다. 강우가 차단된 관측지의 토양 호흡($F_c$)의 일변화는 0.2m 깊이의 토양 온도의 일변화와 매우 비슷하였으며, 자정에 최고값을 보이고 정오에서 이른 오후 사이에 최저값을 나타내었다. 이러한 뚜렷한 일변화 패턴은 같은 관측지에서 강우가 차단되지 않은 상태에서 관측된 선행연구의 결과(뚜렷한 일변화의 부재)와 대조되었다. 또한, 자연상태의 가능토양호흡(potential soil respiration, $F_{cal}$)의 크기와 비교할 때, 강우가 차단된 관측지의 토양호흡은 매우 큰 차이(예를 들면, 토양수분이이 부족할 때 약 50% 감소)를 보였다. 이 연구결과는 강우가 토양 $CO_2$ 플럭스의 크기뿐만이 아니라 토양온도의 연직 프로파일을 바꿈으로써 토양호흡의 일변화 양상에도 영향을 미침을 보여준다.