• Horticultural Science & Technology
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• v.19 no.3
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• pp.384-388
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• 2001

The selenium (Se) contents of 20 herbs, harvested in three areas in Korea, were analyzed. Many herbs had no Se. Angelica ($138.4{\mu}g \;Se{\cdot}kg^{-1}$ FW), caraway ($167.8{\mu}g \;Se{\cdot}kg^{-1}$ FW), chamomile ($116.6{\mu}g \;Se{\cdot}kg^{-1}$ FW), marjoram (158.7 and $132.6{\mu}g\;Se{\cdot}kg^{-1}$ FW), and oregano ($62.5{\mu}g\;Se{\cdot}kg^{-1}$ FW) accumulated Se as higher concentration compared with other plants. The Se content of herbs was dependent on the species, cultivars and areas. The status of Se uptake by herbs was investigated according to Se concentrations in hydroponics. During four weeks, before harvest of several herbs in greenhouse, sodium selenate ($Na_2SeO_4$) was added to the nutrient solution at concentrations of 2, 4, 6, and $8mg{\cdot}L^{-1}$. Field-mint accumulated Se too high, but external symptom of Se toxicity was not found. Essential oil content was generally proportionated to treated-Se concentration. The essential oil contents in basil and balm increased two to three times higher by sodium selenate treatment compared to non-treatment, but they did not show any linear relationship between essential oil contents and treated-Se concentration.

• Korean Journal of Plant Taxonomy
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• v.49 no.4
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• pp.371-373
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• 2019

While conducting a floristic study of Korean moss, we discovered one unrecorded species collected from Mt. Hallasan in Korea. Brachydontium olympicum (E. Britton) T. T. McIntosh & J. R. Spence is recorded for the first time for Korea. Unlike other species of Brachydontium, this species has no peristome and its distal laminal cells are mostly isodiametric.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.199-204
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• 2012

This study was conducted to estimate climax index by eco-morphology for major 36 tree and sub-tree species in natural deciduous forests so as to interpret seral position of each species in the forest community. Fourteen eco-morphological characters which were considered to be associated with successional gradient in the forest were selected for the study. Four levels per character for each species were given on a standardized scale of increasing climax, and the index was computed by the proportion of the sum of total scores, expressed by percent values. With calculated mean value of 54.8 for all indices, Carpinus cordata had the highest index value of 90.5, and Populus davidiana recorded the lowest of 13.2. The most climax group, greater than 70 of the index, contained only 8 species, intermediate group, between 41 to 70 of the index, had 23 species, and the most pioneer group, less than 40 of the index comprised 5 species. The result has noticed that the large number of species would take advantage of most diverse resource and niche in the intermediate stage of the sere in the forest. By cluster analysis all 36 species were subjected to be classified into several species groups which had common similar eco-morphological characteristics. The indices were additionally plotted on the two dimensional graph to recognize the positions related to the light absorption factor and reproduction factor. The climax index of tree and sub-tree species developed by this study could be applied to understand the present status of successional stage on the basis of species composition by the method of summing up the indices. And comparison of forest successional stage among various forest communities could be done by summing up the climax indices of composed species in each community. However, this kind of applied methodology should be limited to the forest of similar species composition and site condition.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.2
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• pp.95-106
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• 2021

The SO₄ in the jarosite structure can be substituted by other oxyanions, and therefore, the transition of jarosite to goethite plays a very important role in controlling the behavior of oxyanions. In this study, the phase change according to the species of the oxyanion in jarosite and the related behavior of the oxyanion was studied by mineralogical and geochemical methods when jarosite, which is coprecipitated with various oxynions, undergoes a phase change by a reductive dissolution. Jarosite substituted by five oxyanions by 5 mol% was used in this study. The mineral phase change induced by reductive dissolution using ammonium oxalate was investigated, and the order of phase transition rate of jarosite to goethite was MoO₄-jarosite ≥ SeO₄-jarosite ≥ CrO₄-jarosite > pure jarosite > SeO₃-jarosite > AsO₄-jarosite, showing that the transition rates vary depending on the substituted oxyanion. The resultant concentration of the leached Fe was slightly different depending on the type of oxyanion and time but did not show a noticeable difference. The concentration of each oxyanion leached according to the change of the mineral phase showed that the order of concentration of oxyanions was Mo > Se(SeO₃) > As > Se(SeO₄) > Cr in general, and showed a slight increase with time. This trend was related to the species of oxyanions rather than mineral phase change. The results of this study showed that the phase transition of jarosite to goethite was affected by the species of oxyanions, but this tendency did not affect the concentrations leached oxyanions.

• Journal of the Korean Chemical Society
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• v.64 no.4
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• pp.203-209
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• 2020

Selenium species in hair and nails were extracted, separated and analyzed with HPLC-ICP/MS. The result showed that Se species was mostly SeCys and the information related to the change of selenium concentration in a body could be obtained. The Se fortification study was performed for 5 participants during 12 months. The average of Se concentration was 858.6 ± 201.2 ng g^-1, which did not change much during the research period nor the difference between the individuals was striking. In the case of hair, the average concentration was 205.3 ng g^-1 which was lower than nails. Se supplement of 22 ㎍ day^-1 was taken for 3 months by the volunteers and the difference between before and after (3 months period for each) the taking of supplement was not striking. However, when the dose was increased to 300 ㎍ day^-1 for 2 months, the concentration was increased noticeably to 1,230 ng g^-1. It can be thought that the analysis of finger nail for Se can provide valuable information for the long period (several months) of exposure or intake of Se for a human body.

• Korean Journal of Environment and Ecology
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• v.16 no.2
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• pp.160-171
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• 2002

In order to clarify the species composition, distribution and habitat of the Korean wild Pyrus ussuriensis and P. pyrifolia communities, that are so expected as a useful resource plant, an investigation was carried out according to phytosociological method on Mts. Hambaek, Ilwol, Sobaek, Juwang and Gaya in Korea. In the present study, we made an attempt to elucidate the autecological characteristics of the wild Pyrus species by synecological approach. As a result, the forests including the Pyrus species were divided into the two associations and two communities, considering the existing vegetation units for the forest; Syneilesio-Quercetum serratae, Corylo-Quercetum mongozicae, Ainsziaea acerifolia- Quercus mongolica community and Fraxinus rhynchophylla-Pyrus ussuriensis community. Among the units, the Syneilesio-Quercetum serratae and the Corylo-Quercetum mongolicae belong to southern type and middile-northern type, respectively, in their distributional type. It is inferred that the wild Pyrus species are distributed preferably in the deciduous forest zone in Korea, compared to the other forest zones. In particular the Pyrus species are present alone or dominantly in only both the tree layer or subtree layer of the forests, reflecting their shade intolerance ecophysiologically. Thus they usually were distributed in SE or SW of slope aspect. Generally the canopy of the forests including the Pyrus species was so open. Species diversity of the vegetation units was highest in the Syneizesio-Quercetum serratae and lowest in the Ainsliaea acerifolia-Quercus mongolica community. The Corylo-Quercetum mongolicae and the Pyrus ussuriensis-Fraxinus rhynchophylla community are medium between the two.

• Analytical Science and Technology
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• v.27 no.3
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• pp.140-146
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• 2014

An internal standard was used in PCID (post column isotope dilution) to improve the accuracy and precision in quantification of various chemical species. The error occurring in the column was the largest in HPLC-ICP/MS (high performance liquid chromatography-inductively coupled plasma/mass spectrometry) when PCID and other traditional quantification methods were compared with each other. Internal standard was effective in correcting the loss of sample in the column to improve accuracy and precision. When applied to SeMet, using MeSecys or $Se^{4+}$ as an internal standard, relative errors were reduced from 31% and 13% to less than 1%, while standard deviations were reduced from 5.1% and 6.9% to 1.5% and 0.2%, respectively. Positive aspects of using an internal standard in PCID were compared with other quantitative techniques and discussed in detail.

• Analytical Science and Technology
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• v.24 no.4
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• pp.298-303
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• 2011

Selenium is one of the interesting elements in human body, because it's important micro-nutrient for human health as the essential biological tissue in protein. Selenite ($SeO_3^{2-}$) and selenate ($SeO_4^{2-}$) are the dominant dissolved selenium species in natural water, and their toxicity and chemical properties are very different each other. Thus it is necessary to separate the two selenium species for understanding selenium behaviors in natural waters. Some reported methods, using an alumina-filled column and an ion chromatography, to separate the selenite and selenite may be difficult to directly apply to the natural water. Therefore magnetite selectively adsorbs selenite and selenate according to pH of solution, the separation of selenite and selenate using a magnetite-filled column was successfully obtained at weak alkali solutions. Moreover, the influence of dissolved anions in natural water at the selenite sorption onto magnetite was also investigated because they could hinder the sorption of selenite onto magnetite. In other to directly apply to the natural water, reactive sites of magnetite should be considered because dissolved silicate in natural water can hinder the adsorption of selenite onto magnetite.

• Toxicological Research
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• v.29 no.1
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• pp.35-42
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• 2013

Quantum dots (QDs) have received considerable attention due to their potential role in photosensitization during photodynamic therapy. Although QDS are attractive nanomaterials due to their novel and unique physicochemical properties, concerns about their toxicity remain. We suggest a combination strategy, CdSe/ZnS QDs together with curcumin, a natural yellow pigment from turmeric, to reduce QD-induced cytotoxicity. The aim of this study was to explore a potentially effective cancer treatment: co-exposure of HL-60 cells and human normal lymphocytes to CdSe/ZnS QDs and curcumin. Cell viability, apoptosis, reactive oxygen species (ROS) generation, and DNA damage induced by QDs and/or curcumin with or without ultraviolet A (UVA) irradiation were evaluated in both HL-60 cells and normal lymphocytes. In HL-60 cells, cell death, apoptosis, ROS generation, and single/double DNA strand breaks induced by QDs were enhanced by treatment with curcumin and UVA irradiation. The protective effects of curcumin on cell viability, apoptosis, and ROS generation were observed in normal lymphocytes, but not leukemia cells. These results demonstrated that treatment with QD combined with curcumin increased cell death in HL-60 cells, which was mediated by ROS generation. However, curcumin acted as an antioxidant in cultured human normal lymphocytes.

• Korean journal of applied entomology
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• v.30 no.3
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• pp.212-218
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• 1991

Pathogenicity of Spodoptera exigua nuclear polyhedrosis virus (SeMNPV) against the host insect and 8 species of lepidopterous insects and cross infection of baculoviruses to third instar of S. exigua larvae were studied to determine as a biocontrol agent for S. exigua. The median lethal concentrations($LC_{50}$)of the SeMNPV to egg mass was $2.855\times10^5$ PIBs/ml and higher than that to the larvae of S. exigua. Mortality of the SeMNPV in third ins tar larvae was more increased than that in first and fifth instar of S. exigua larvae by 1.16 and 4.11 times, respectively. The median lethal times($LT_{50}$) to $1.56\times10^6$ PIBs/ml was in the range of 4.25 to 5.04 days. Infectivity of the SeMNPV against eight species of lepidopterous insects was showed only in the host insect, S. exigua. Autographa cali/ornica MNPV, Mamestra barassicae MNPV, and Trichoplusia ni MNPV were cross-infected to third instar of S. exigua larvae among ten of baculoviruses tested.