• Economic and Environmental Geology
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• v.45 no.2
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• pp.137-144
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• 2012

Soil pan typically presents the problems in soil water movement or in aeration which is not appropriate for a plant root growth, In this study physico-chemical characteristics of soils and micromorphological characteristic of clay accumulated zone were investigated to identify redox characteristic and evolution of a fragipan of Gangreung series commonly developed in coastal terraces. Gangreung series is classified as Aquic Fragiudalfs according to the USDA soil taxonomy. It is known that sedimentary ocean floor results in soil pan having parallel liner soil structure due to landscape evolution around 200 to 250 million years ago. it is considered that illite, kaolinite, and vermiculite are major clay minerals contained in a fragipan of Gangreung series. Mixed gray and reddish brown colored band around soil pores was found and would be the redoxmorphic features of fragipan. It is possibly due to accumulated illuvial clay and ferriargillans in soil pores and aggregates in reducing conditions eluding ferrous material. Therefore, mixed colored band around pores in soils of Gangreung series would be developed from the eluted ferrous materials which were accumulated in fragipan during the emerged land formation.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.224-228
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• 2015

The carbon precursor pitch from pyrolyzed fuel oil (PFO), by-product of Naphta cracking process (NCC), was prepared through heat and UV irradiation treatments with various concentrations of $AlCl_3$, which is a new pitch preparation method. The reformed pitches were characterized by measuring their elemental composition, chemical structure of components, molecular weight distribution, and softening point. The oxygen contents of reformed pitch increased as increasing $AlCl_3$ amounts on the other hand, the carbon and hydrogen contents were not nearly changed. UV irradiated reformed pitches were composed of more aromatic carbon compounds than that of using only heat-treatment without any UV irradiation. The addition of $AlCl_3$ catalyst was ineffective on the aromaticity of reformed pitches. The softening point of prepared pitches was in the range of $103.3{\sim}168.9^{\circ}C$. Also the yield of prepared pitch increased from 48% to 80% when 5 wt% of $AlCl_3$ was added during the heat and UV irradiation reforming. It is expected that the UV irradiation reforming method can be practical and helpful to produce high yields of pitches with diverse properties.

• Korean Journal of Ecology and Environment
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• v.45 no.3
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• pp.289-301
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• 2012

A biological assessment of water quality was made at 9 sites of the Joyang-river and inflow streams located in Jeongseon-gun Gangwon-do, from June 2008 to September 2010. The investigation consisted of physico-chemical factors, biomass, and standing crops of epilithic diatoms. In addition, the community structure of epilithic diatoms was analyzed, and the water quality was assessed using DAIpo and TDI. The pH varied from 7.4~10.2 which is attributed to the Joyang-river area consisting of limestone. A total of 117 taxonomic groups of epilithic diatoms, including: 2 orders, 6 families, 23 genera, 95 species, 15 varieties, 2 forms, and 5 unidentified species, were found in the Joyang-river. 11 taxa, including Achnanthes laterostrata and Cymbella delicatula which live in neutral to alkali pH, were found. An indicator species of alkali waters, Cymbella delicatula, was routinely observed to have a relative frequency of over 10% in I3 and I4. In the result of the biological assessment using DAIpo, the Joyang-river was rated class A, with an average of 77.03 and inflow streams were rated class B with an average of 65.84. As for the results of TDI analysis, the Joyangriver was rated class A~B, and inflow streams were rated class A~D. Accordingly, the water quality of the Joyang-river was determined to be superior to that of inflow streams. Although the main stream showed low water quality at sites J2 and J3, correlating with a reduction in the quality of inflow stream, I1 in September 2009.

• Journal of Life Science
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• v.24 no.11
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• pp.1238-1243
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• 2014

Mesenchymal stem cells (MSCs) have been widely used as cellular therapeutic agents. They have their own characteristic stemness, and thus, they can be used in the treatment of many chronic diseases and in anticancer therapy. MSC therapy has many advantages over chemical therapy. MSC therapy is based on self or homogeneous origin; as such, it is expected to be effective in the treatment of various diseases. In addition, microRNAs in particular have been studied for their structure and function, and they are also expected to prove effective for use as therapeutic agents in cancer or chronic diseases. MicroRNAs are largely associated with metabolism and homeostasis. Therefore, over- or under-expression of microRNAs leads to chronic diseases. Conversely, effective control of the expression of specific microRNAs reduces the risk of many chronic diseases. However, there have been no reports thus far on the synergistic effects of MSCs and microRNAs. Therefore, in this study, we examined the relationship between MSCs and microRNAs using placenta-derived MSCs (PDSCs), bone marrow-derived MSCs (BM-MSCs), and fibroblast (WI-38) cells. We studied the expression of some microRNAs in MSCs and compared the expression in each cell line and cell passage. As a result, we found that the expression of microRNA-34a was higher in PDSCs than in BM-MSCs and that the expression of microRNA-27a, 33a, 33b, and 211 was higher in BM-MSCs than in PDSCs. Therefore, we expect that each MSC line will be used as cell therapy, considering its expressed functional microRNA.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.49-62
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• 2001

Hydrographic surveys were carried out seven times during May 31, 1998 and September 24, 1998 in order to study the physical environments of the coastal area between Narodo Is. and Sorido Is. in the southern sea of Korea (the South Sea) where the occurrence of Cochlodinium polykrikoides red tide is frequently observed in summer. Temperature and salinity of the water column from the surface to the depth of 30 m exhibit large seasonal variations. Mean temperature of the water column increased by 6 and mean salinity of the water column decreased by 2.71 psu during the observation period. Both the freshwater supplied from the adjacent land and the precipitation over the study area cannot account for the observed salinity variations. The influx of the low salinity water from the offshore area is considered to be the main cause for the observed salinity changes. Surface salinity in the study area shows different spatial distribution in the period of outbreaking, mid-stage and disappearance of the red tide. Especially, salinity was abruptly lowered at the stage of disappearance of red tide as compared to salinity of the previous observation period. Vertical structure of water properties also became vertically homogeneous at the disappearance stage, while it was highly stratified in the previous observation. Such changes can only be explained by the inflow of low salinity water from the offshore, which is considered as the most possible cause for the disappearance of the red tide in the study area. This study suggests that exchanges of water, and chemical and biological factors between coastal areas and of shore area in the South Sea need to be studied in association with the general circulation of the South Sea in order for the better understanding of the occurrence and disappearance of the red tide in the coastal area of the South Sea.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.1
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• pp.87-91
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• 2005

Dental plaque is a film of microorganisms on the tooth surface that plays an important part in the development of caries and periodontal diseases. Streptococcus mutans (S. mutans) is present in almost all types of dental plaque. Teeth and their supporting structure, the gums (gingiva) are subjected to infection by S. mutans that causes cavities and pyorrhea which, if left untreated, can eventually lead to gingivitis. Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. The present study was designed to investigate the effect of Aralia continentalis (Araliaceae) extracts on the growth, acid production, adhesion, and insoluble glucan synthesis of S. mutans. The methanol extract of A. continentalis showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.25, 0.5, 1, 2 and 4 mg/ml compared to the control group. The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 60% at the concentration of 0.25 mg/ml and complete inhibition was observed at the concentration of 4 mg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan from sucrose, methanol extract of A. continentalis showed more than 10% inhibition over the concentration of 0.25 mg/ml. The synthesis of insoluble glucan was decreased in the presence of 0.25 - 4 mg/ml of the methanol extract of A. continentalis. Hence, we conclude that A. continentalis might be a candidate of anticaries agent.

• Korean Journal of Pharmacognosy
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• v.16 no.4
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• pp.233-238
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• 1985

A number of sedative alkaloids were isolated from Sanjoin(酸棗仁), the seeds of Zizyphus vulgaris Lamark var. spinosus Bunge (Rhamnaceae) which is an important Chinese medicinal material used to treat insomnia and sometimes to treat sleepiness. Those compounds were designated as Sanjoinine-A, B, C, D, etc. depending on the order of increasing polarity. Sanjoinine-A, $C_{31}H_{42}N_4O_4$, $mp\;249^{\circ}$, $[{\alpha}]^{27}_D-316$, Sanjoinine-B, $C_{30}H_{40}N_4O_4$, $mp\;212{\sim}4^{\circ}$, Sanjoinene, $C_{29}H_{35}N_3O_4$, $mp\;281{\sim}2^{\circ}$, $[{\alpha}]^{22}_D-272$, Sanjoinine-D, $C_{32}H_{46}N_4O_5$, $mp\;256{\sim}8^{\circ}$, $[{\alpha}]^{22}_D-53.6$, Sanjoinine-F, $C_{31}H_{42}N_4O_5$, $mp\;228{\sim}9^{\circ}$, $[{\alpha}]^{22}_D-215$, and $Sanjoinine-G_1,\;C_{31}H_{44}N_4O_5,\;mp\;236{\sim}8^{\circ},\;[{\alpha}]^{22}_D-68.6$, were found as 14-membered cyclic peptide alkaloids, $Sanjoinine-G_2,\;C_{30}H_{42}N_4O_4,\;mp\;182^{\circ},\;[{\alpha}]^{22}_D-79.2$, as being open chain peptide alkaloid, and Sanjoinine-E, $C_{19}H_{21}NO_2$, $mp\;166^{\circ}$, $[{\alpha}]^{20}_D-146.2$, N-Methylasimilobine, $C_{18}H_{19}NO_2$, $mp\;193{\sim}5^{\circ}$, $[{\alpha}]^{20}_D-204$, Sanjoinine-Ia, $C_{18}H_{19}NO_2$, $mp\;155{\sim}7^{\circ}$, $[{\alpha}]^{20}_D-140$, Sanjoinine-Ib, $C_{19}H_{21}NO_4$, $mp\;184^{\circ}$, Sanjoinine-K, $C_{16}H_{19}NO_3$, $mp\;159{\sim}61^{\circ}$, $[{\alpha}]^{20}_D+35$, Caaverine, $C_{17}H_{17}NO_2$, $mp\;204^{\circ}$, $[{\alpha}]^{20}_D-80$, and Zizyphusine, $C_{20}H_{24}NO_4$, $mp\;214{\sim}6^{\circ}$, $[{\alpha}]^{20}_D+317$ as being aporphine alkaloids. The heat treatment of the cyclic peptide alkaloids produced their isomeric products which showed enhanced sedative activity. The chemical structure of the isomeric products will be discussed.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.38-45
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• 2006

The main objective of this study is the improvement of the interfacial adhesion of RHF-polypropylene (PP) bio-composites through NaOH and acetic acid treated RHF. After manufacturing of untreated and NaOH and acetic acid treated RHF filled PP bio-composites, the effect on interfacial adhesion of bio-composites was investigated. Tensile strength of the bio-composites made from treated RHF with NaOH and acetic acid was higher than that of the untreated bio-composites. The RHF surface before and after NaOH and acetic acid treatment was clearly confirmed by scanning electron microscopy (SEM) micrograph. It was found that both treatments result in a removal of impurity materials of RHF surface by SEM micrographs. The chemical structures of untreated and NaOH and acetic acid treated RHF were confirmed by fourier transform infrared (FTIR). The crystallization structure and crystallinity of non-treated, NaOH and acetic acid treated RHF were investigated by wide-angle X-ray scattering (WAXS).

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.1013-1023
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• 2003

This study was performed to improve water quality of stream by applying hydraulic structures (weir and river bed material) made of porous concrete. The physical and chemical characteristics of porous concrete were measured to estimate application possibility of it in hydraulic structures and it was considered as a proper material for the hydraulic structures. In the results of comparison for the component of matters attached on the hydraulic structures made of porous and ordinary concrete, DW (dry weight) amount attached on porous concrete was 1.6 times higher than that on ordinary concrete under the condition of the same flow rate but influence by flow rate (difference of 10 times) was not shown. Therefore, we could understand that the material of media was more important in DW amount than flow rate. The rate of AFDM (ash free dry mass) to DW also was more at porous concrete than at ordinary concrete. Especially, the high rates of nitrogen and phosphorous in matters attached on porous concrete verify that they were removed by assimilation, adsorption and metabolism of periphyton. The removal percentage of SS, BOD, COD, T-N and T-P by hydraulic structures applying porous concrete compared with ordinary concrete was increased by 34.6%, 36.9%, 33.9%, 18.3% and 21.6%, respectively. Therefore, applying porous concrete to hydraulic structure is expected to contribute to improvement of stream water quality.

• Membrane Journal
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• v.28 no.1
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• pp.75-82
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• 2018

Forward osmosis (FO) desalination system has been highlighted to improve the energy efficiency and drive down the carbon footprint of current reverse osmosis (RO) desalination technology. To improve the trade-off between water flux and salt rejection of thin film composite (TFC) desalination membrane, thin film nanocomposite membranes (TFN), in which nanomaterials as a filler are embeded within a polymeric matrix, are being explored to tailor the separation performance and add new functionality to membranes for water purification applications. The objective of this article is to develop a graphene nanocomposite membrane with high performance of water selective permeability (high water flux, high salt rejection, and low reverse solute diffusion) as a next-generation FO desalination membrane. For advances in fabrication of graphene oxide (GO) membranes, layer-by-layer (LBL) technique was used to control the desirable structure, alignment, and chemical functionality that can lead to ultrahigh-permeability membranes due to highly selective transport of water molecules. In this study, the GO nanocomposite membrane fabricated by LBL dip coating method showed high water flux ($J_w/{\Delta}{\pi}=2.51LMH/bar$), water selectivity ($J_w/J_s=8.3L/g$), and salt rejection (99.5%) as well as high stability in aqueous solution and under FO operation condition.