• Ocean and Polar Research
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• 제41권2호
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• pp.89-97
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• 2019

Long chain plant waxes (n-alkanes, n-alkanoic acids, and n-alcohols) and their carbon isotopic compositions (${\delta}^{13}C$) in geologic archives are valuable tools for paleovegetation reconstruction. However, the sensitivity of different plant wax constituents to vegetation shift is not well understood. This study explores controls on the variation in ${\delta}^{13}C$ values of long-chain n-alkanes ($C_{27}$ to $C_{33}$) and n-alkanoic acids ($C_{26}-C_{30}$) in the Gulf of Mexico core sediments (ODP 625B) near the Mississippi River delta. n-Alkanoic acids' ${\delta}^{13}C$ values were higher than those of n-alkanes by 1-2‰ on average and such a pattern is the opposite from their isotope fractionation observed in living plants: 1-2‰ smaller in n-alkanes than n-alkanoic acids. We attribute this offset to contributions from aquatic plants or microbes that produce high concentrations of $^{13}C-enriched$ long-chain n-alkanoic acids. The sensitivity of n-alkanes and n-alkanoic acids to vegetation and climate varied among chain lengths. The $n-C_{33}$ alkanes were most sensitive to $C_4$ grassland expansion among n-alkane homologues, while no specific trend was observed in n-alkanoic acids. This is due to the similarity in n-alkanoic acid concentrations between $C_3$ and $C_4$ plants by homologues and low terrestrial plant-derived n-alkanoic acid contributions to the sediments. The results of this study suggest that long chain n-alkanoic acids' ${\delta}^{13}C$ values in sediments may be influenced by contributions from different sources such as aquatic plants or microbial inputs and therefore interpretations regarding this matter should be cautiously formulated. We suggest that there is a need for further studies on characterizing long-chain n-alkanoic acids ($C_{26}-C_{34}$) in aquatic plants and microbes from various climates and environments in order to investigate their production and integration into sedimentary archives.

• 환경생물
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• 제35권4호
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• pp.476-491
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• 2017

물거미(Argyroneta aquatica)는 전 세계적으로 한 종만 존재하는 희귀거미로 수중에서 살며, 국내 서식지인 경기도 연천군 은대리는 천연 기념물 서식지로 지정되어 있다. 그러나 은대리 습지대는 근래 들어 육지화 현상이 이루어져 서식지 손실이 나타나고 있다. 서식지 손실은 물거미 개체수에 직접적인 영향을 미치므로 물거미 보호 조치가 필요하다. 곤충은 생태계 기저에 위치하며, 대상환경의 특징을 직, 간접적으로 대변한다. 물거미 서식지 보호 방안 및 2015년 5월에서 9월 사이 물거미 서식지와 그 주변의 곤충상 조사를 쓸어잡기(sweeping)와 육안조사로 실시하였으며 조사한 곤충군을 군집분석하였다. 곤충상 조사 결과 총 13목 276종 3,929개체가 채집되었다. 가장 많이 채집된 곤충군은 노린재목으로 전체 채집종의 24.2%, 채집 개체의 82.3%를 차지했다. 채집된 전체 곤충상의 군집분석 결과, 우점도 지수는 0.23, 다양도 지수는 2.27, 균등도 지수는 0.41, 풍부도 지수는 31.2로 나타났으며, 이전 조사 자료 결과와 비교하면, 가장 빈번하게 수집된 종이 육상곤충으로 바뀌었고, 이는 물거미의 습지 서식지가 육지 환경으로 빠르게 변화함을 보여주었다.

• 한국균학회지
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• 제43권1호
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• pp.20-25
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• 2015

본 연구에서는 경기도 포천과 강원도 춘천에 자생하는 광릉요강꽃과 강원도 삼척에서 자생하는 복주머니란의 뿌리에서 내생균을 순수 분리하였고, 분리된 균주의 ITS 부위의 염기서열을 이용하여 계통 분석하였다. 그 결과 광릉요강꽃에서는 11종의 균주가 분리되었고, 복주머니란에서는 15종의 균주가 분리되었으며, Leptodontidium orchidicola, Humicola fuscoatra var. fuscoatra, Umbelopsis dimorpha 등의 균주는 공통으로 분리되었다. 분리된 균주 중 Oidiodendron echinulatum, Pseudogymnoascus roseus, Geomyces vinaceus, Cryptosporiopsis ericae, Umbelopsis dimorpha, Chaetomium cupreum 은 국내 미기록종으로 확인하였다.

• Journal of Photoscience
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• 제7권3호
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• pp.87-95
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• 2000

As sunlight not always optimized for every terrestrial plant in terms of light quality, quantity and duration, some plants suffer detrimental effects of sunlight exposure under certain conditions. Photoinhibition of photosynthesis is a typical phenomenon representing harmful light effects, commonly observed in many photosynthetic organisms. It is generally accepted that functional, structural loss of photosystem II complex(PSII) is the primary event of photoinhibition. Accumulating data also suggest that singlet oxygen($^1$O$_2$) is the main toxic species directly involved in it. There are two different views on the specific site and mechanism of $^1$O$_2$ production in the photosynthetic membrane. One of them favors the PSII reaction center, where the primary charge pairs recombination occurs as a prerequisite for the generation of $^1$O$_2$, and the other inclines to photosensitized $^1$O$_2$ formation by a substance located outside PSII. This article describes how we, as the advocators of the latter concept, have arrived at the conclusion that $^1$O$_2$ immediately involved in PSII photodamage is largely generated from the Rieske center of the cytochrome b$_{6}$/f complex and diffuses into PSII, attacking the reaction center subunits.s.

• Toxicological Research
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• 제26권4호
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• pp.253-259
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• 2010

We are consistently being exposed to nanomaterials in direct and/or indirect route as they are used in almost all the sectors in our life. Nations across the worlds are now trying to put global regulation policy on nanomaterials. Sometimes, they are reported to be more toxic than the corresponding ion and micromaterials. Therefore, safety research of nanoparticles has huge implications on a national economics. In this study, we evaluated and analyzed the research trend of ecotoxicity of nanoparticles in soil environment. Test species include terrestrial plants, earthworms, and soil nematode. Soil enzyme activities were also discussed. We found that the results of nanotoxicity studies were affected by many factors such as physicochemical properties, size, dispersion method and test medium of nanoparticle, which should be considered when conducting toxicity researches. In particular, more researches on the effect of physicochemical properties and fate of nanoparticles on toxicity effect should be conducted consistently.

• Carbon letters
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• 제8권3호
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• pp.191-198
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• 2007

Recent studies have revealed the poisonous nature of aluminum(III) species to aquatic and terrestrial organisms. Therefore, this investigation aims to develop batch adsorption experiments in the laboratory, aiming to the removal of aluminum(III) from aqueous solutions onto powdered activated carbon (PAC). The latter (which is an effective and inexpensive sorbent) was prepared from olive stones generated as plant wastes and modified with an aqueous modifying oxidizing agent, viz. $HNO_3$. The main parameters (i.e. initial solution pH, sorbent and $Al^{3+}$ ions concentrations, stirring times and temperature) influencing the sorption process were examined. The results obtained revealed that the sorption of $Al^{3+}$ ions onto PAC is endothermic in nature and follows first-order kinetics. The adsorption data were well described by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% $Al^{3+}$ ions in the concentration range $1.35-2.75\;mg{\cdot}l^{-1}$ was attained. Moreover, the procedure was successfully applied to the recovery of aluminum spiked to some environmental water samples with an RSD (%), does not exceed 1.22%.

• 한국농림기상학회지
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• 제11권3호
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• pp.118-122
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• 2009

Net Radiation ($R_N$) is the major driving force for biophysical and biogeochemical processes in the terrestrial ecosystems, which is one of the most critical variables in both measurement and modeling. Despite its importance, there are only 10 weather stations conducting $R_N$ measurements among the 544 stations operated by Korea Meteorological Administration (KMA; KMA, 2008). The measurement of incoming shortwave radiation ($R_S{\downarrow}$) is, however, conducted at 22 stations while that of sunshine duration is conducted at all the manned stations. In this context, the recent research for estimating $R_N$ using $R_S{\downarrow}$ in Korean peninsula by Kwon (2009) is of great worth. The author used a linear regression and the radiation balance methods. We generally agree with the author that, in terms of simplicity and practicality, both methods show reliable applicability for estimating $R_N$. We noted, however, that the author's experimental method and analysis need some clarification and improvement, that are addressed in the following perspectives: (1) the use of daily integrated data for regression, (2) the use of measured albedo, (3) the use of linear coefficients for whole year data, (4) methodological improvement, (5) the use of sunshine duration, and (6) the error assessment.

• Journal of Species Research
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• 제11권2호
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• pp.98-101
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• 2022

The genus Tripylina Brzeski, 1963 is a group of terrestrial nematodes that inhabit soil and semi-wet biomes, most of which have been reported from Europe, Asia, America, Africa, and New Zealand. Tripylina stramenti (Yeates, 1971) Tsalolikhin, 1983, belonging to the family Trischistomatidae Andrassy, 2007, is newly discovered from Korea. The specimens were collected from the edge of the valley of Ulleung-gun, Gyeongsangbuk-do, South Korea. Tripylina stramenti described herein shows typical morphological characters of the genus Tripylina, including six and four setae in a single whorl, present dorsal tooth and subventral teeth, prodelphic reproductive system of female, absence post-uterine sac, narrow sickle-shaped spicule of male and generally S-shaped tail. The specimens differ in their body width (from the New Zealand populations), outer labial setae length, cuticles thickness(from the West African populations), and nerve ring position (from Indian populations). This species is distinguished from other Tripylina species by its relatively large body, two anterior and subventral teeth, and single cervical seta. In this study, morphological characteristics and morphometric information of the Korean T. stramenti isolate are described, illustrated, and compared with the same species from other geographic origins.

• 복합신소재구조학회 논문집
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• 제3권3호
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• pp.1-8
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• 2012

Recently, underground pipes are utilized in various fields of applications such as sewer lines, drain lines, water mains, gas lines, telephone and electrical conduits, culverts, oil lines, etc. Most of pipes are installed for long-term purposes and they should be safely installed in consideration of installation conditions because there are unexpected various terrestrial loading conditions. In this paper, we present the result of investigation pertaining to the structural behavior of glass fiber reinforced thermosetting polymer plastic (GFRP) flexible pipes buried underground. The mechanical properties of the GFRP flexible pipes produced in the domestic manufacturer are determined and the results are reported in this paper. In addition, ring deflection is measured by the field tests and the finite element analysis (FEA) is also conducted to simulate the structural behavior of GFRP pipes buried underground. From the field test results, we predicted long-term, up to 50 years, ring deflection of GFRP pipes buried underground based on the method suggested by the existing literature. It was found that the GFRP flexible pipe to be used for cooling water intake system in the nuclear power plant is appropriate because 5% ring deflection limitation for 50 years could be satisfied.

• 식물분류학회지
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• 제50권4호
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• pp.385-394
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• 2020

To elucidate the molecular phylogeny of Neottia japonica, which is a terrestrial orchid distributed in East Asia, the internal transcribed spacer (ITS) of nuclear DNA and the matK of chloroplast DNA were used. A total 22 species of 69 accessions for ITS and 21 species of 114 accessions for matK phylogeny were analyzed with the maximum parsimony and Bayesian methods. In addition, we sought to establish a correlation between the distribution, morphology of the auricles and genetic association of N. japonica with phylogenetic data. The phylogenetic results suggest that N. japonica is monophyletic and a sister to N. suzukii in terms of the ITS phylogeny, while it is paraphyletic with N. suzukii in terms of the matK phylogeny. N. japonica and N. suzukii show similar morphologies of the lip and column, they both flower in April, and they are both distributed sympatrically in Taiwan. Therefore, it appears to be clear that N. japonica and N. suzukii are close taxa within Neottia, although there is incongruence between the nrDNA and cpDNA phylogenies of N. japonica. The incongruence between the two datasets may have various causes, meaning that further studies are needed to confirm the evolutionary process of N. japonica. The phylogenetic status of N. kiusiana, which was not included in previous studies, was as a sister to N. nidus-avis. Meanwhile, the ITS and matK phylogenies are unsuitable for identifying genetic associations with the characteristic of auricles. The phylogenetic topologies of Korean, Taiwanese and mainland Chinese individuals suggest that the populations of N. japonica in Korea originated from China's mainland and island areas. The characterization of regional gene differences could provide useful preliminary data for future studies.