• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.545-553
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• 2017

Microalgae can offer an attractive way of generating renewable and sustainable biodiesel. Biodiesel derived from microagae can have lower impact on the environment and food supply than biodiesel produced from crops. But biodiesel derived from microagae have poor fuel properties at low temperature depending on their species. In this study, it was investigated that fuel characteristics of biodiesel derived from Tetraselmis sp. and cold weather performance of biodiesel blend (BD3, 3 vol.% biodiesel - 97 vol.% diesel). The startability and operability of the passenger car in BD3 was good at $-20^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.500-505
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• 2014

In recent years, organic ginseng cultivation has increased because customers prefer organic ginseng products due to the morphological quality as well as the safety such as the residuals of chemically-synthesized pesticides. Therefore, some of paddy and upland fields were converted into organic ginseng fields. Soil chemical properties, soil microflora, and soil-inhabiting animals were investigated in paddy-converted and upland organic ginseng fields in Sangju city, Korea. There was few difference in the soil chemical properties, and the soil nutrient concentrations, such as nitrate-N, Av. $P_2O_5$ between the two field types, and exchangeable cations such as K and Ca were within the ranges which are recommended by the standard ginseng-farming manual. Changes in microflora were also assessed by analyzing phospholipid fatty acid composition. Overall, indicators of microbial groups were greater in the upland field than in the paddy-converted soil, but they were not significantly different. In addition, there was no significant change in the abundance of nematodes, collembolans, and mites between the two field types probably because of the high variation within the field types. In this study, it was suggested that soil chemical and biological properties for organic ginseng cultivation were greatly influenced by the variation of topography and soil management practices rather than field types. Further study may be needed to investigate the influence of these factors on soil chemical and biological properties in organic ginseng soils.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.125-130
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• 2006

In order to utilize non-commercial melon as alcoholic beverage material, in this study the optimum fermentation method and manufacture conditions were investigated and thereafter the properties of final product were determined. As for melon wine made with only melon juice, sensorial properties, particularly flavor, were not acceptable as alcoholic beverage. To improve the lack of melon wine, we made mash with cooked rice and Nuruk, and then added melon juice during fermentation. Acceptable sensorial properties were obtained in melon wine when 30% extract juice of oriental melon was added after 4 day of fermentation. The alcoholic beverage added melon juice showed much higher yellowness value than that without melon juice indicating that a clear yellow color similar to melon was actually observed in final product. Adding melon juice led little changes in amount and composition of free sugars, organic acids and amino acids and could improve sensorial properties.

• Molecules and Cells
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• v.38 no.2
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• pp.122-129
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• 2015

DBM-2198, a six-membered azasugar nucleotide (6-AZN)-containing phosphorothioate (P = S) oligonucleotide (AZPSON), was described in our previous publication [Lee et al. (2005)] with regard to its antiviral activity against a broad spectrum of HIV-1 variants. This report describes the mechanisms underlying the anti-HIV-1 properties of DBM-2198. The LTR-mediated reporter assay indicated that the anti-HIV-1 activity of DBM-2198 is attributed to an extracellular mode of action rather than intracellular sequence-specific antisense activity. Nevertheless, the antiviral properties of DBM-2198 and other AZPSONs were highly restricted to HIV-1. Unlike other P = S oligonucleotides, DBM-2198 caused no host cell activation upon administration to cultures. HIV-1 that was pre-incubated with DBM-2198 did not show any infectivity towards host cells whereas host cells pre-incubated with DBM-2198 remained susceptible to HIV-1 infection, suggesting that DBM-2198 acts on the virus particle rather than cell surface molecules in the inhibition of HIV-1 infection. Competition assays for binding to HIV-1 envelope protein with anti-gp120 and anti-V3 antibodies revealed that DBM-2198 acts on the viral attachment site of HIV-1 gp120, but not on the V3 region. This report provides a better understanding of the antiviral mechanism of DBM-2198 and may contribute to the development of a potential therapeutic drug against a broad spectrum of HIV-1 variants.

• Journal of Applied Biological Chemistry
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• v.48 no.2
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• pp.79-83
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• 2005

While screening for nematicidal activity of bacterial origins, various pseudomonads strains were inhabited in tomato rhizosphere. One isolate designated as $PE_{10}$ was selected for studies on nematicidal properties and plant growth-promoting (PGP) activity and was identified as Pseudomonas aeruginosa based on morphological features, biochemical and physiological tests, and carbohydrate utilization. To investigate nematicidal activity, Meloidogyne incognita juvenile mortality was determined using $PE_{10}$ culture filtrate. Inhibition of strain $PE_{10}$ against Fusarium oxysporum was observed using dual culture technique. Strain $PE_{10}$ showed good siderophore activity, HCN and IAA production abilities, and growth and development enhancement of tomato.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.297-297
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• 2006

Recently columnar liquid crystals have been studied due to their possible application to organic conducting materials. Supramolecular columnar liquid crystals consist of mesogenic unit which can aggregate into discs that will make up the columns which associate to form a two-dimensional network. In this study, we prepared supramolecular columnar liquid crystals containing hydrogen bonding between carboxylic acid and, pyridine moieties. Thermal and structural properties of prepared complexe were investigated, and it exhibited hexagonal columnar structure ($Col_{h}$) at room temperature.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.70-73
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• 1996

Many researchers had considered biological systems as linear systems. In many cases of biological systems, the phenomena that show the regular and periodic dynamics are considered the normal state. However, some clinical experiments reported, in some cases, the periodic signals represented the abnormal state. We assume that signals from human body system are generated from deterministic, intrinsic mechanisms and can be represented a simple equation that show nonlinear dynamics dependent on control parameters. The objective of our study is to model a nonlinear dynamics correctly from the nonlinear time series using the genetic programming method; to find a simple equation of nonlinear dynamics using collected time series and its nonlinear characteristics. We applied genetic programming to model RR interval of ECG that shows chaotic phenomena. We used 4 statistic measures and 2 fractal measures to estimate fitness of each chromosome, and could obtain good solutions of which chaotic features are similar.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.308-324
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• 2023

This study investigated unrecorded freshwater bacterial species in Korea. Water and sediment samples were collected from the Nakdong River basin from 2020-2022. Bacterial isolates obtained through the conventional culture method with commercial media were subjected to 16S rRNA gene sequencing to identify unrecorded bacterial species. Results of 16S rRNA gene sequencing of the bacterial isolates revealed that a total of 44 bacterial isolates shared 16S rRNA gene sequence similarities of more than 98.65%, with validly published bacterial species not reported in Korea yet. These isolates were phylogenetically assigned to 4 phyla, 7 classes, 21 orders, 33 families, and 42 genera. A total of 2, 6, 12, and 24 species belonged to phyla Bacillota, Bacteroidota, Actinomycetota, and Pseudomonadota, respectively. Here, we provide details of these 44 unrecorded bacterial species, including Gram staining, colony and cellular morphologies, biochemical properties, and phylogenetic position.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.376-384
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• 2017

In this paper, we describe a case of using robot technology in child studies to examine children's judgement and reasoning of the life phenomenon on boundary objects. In order to control the effects of the appearance of the robot, which children observe or interact directly with, on the children's judgement and reasoning of the life phenomenon, we developed a robot similar to human. Unit experimental scenarios representing biological and psychological properties were implemented based on control of robot's motion, speech, and facial expressions. Experimenters could combine these multiple unit scenarios in a cascade to implement various scenarios of the human-robot interaction. Considering that the experimenters are researchers of child studies, there was a need to develop a remote operation console that can be easily used by non-experts in the robot field. Using the developed robot platform, researchers of child studies could implement various scenarios by manipulating the biological and psychological properties of the robot based on their research hypothesis. As a result, we could clearly see the effects of robot's properties on children's understanding about boundary object like robots.

• Toxicological Research
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• v.33 no.4
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• pp.305-313
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• 2017

Accumulating epidemiological evidence indicates that exposure to fine air pollution particles (APPs) is associated with a variety of adverse health effects. However, the exact physiochemical properties and biological toxicities of fine APPs are still not well characterized. We collected four types of fine particle (FP) (diesel exhaust particles [DEPs], natural organic combustion [NOC] ash, synthetic organic combustion [SOC] ash, and yellow sand dust [YSD]) and investigated their physicochemical properties and in vitro biological toxicity. DEPs were almost entirely composed of ultrafine particles (UFPs), while the NOC, SOC, and YSD particles were a mixture of UFPs and FPs. The main elements in the DEPs, NOC ash, SOC ash, and YSD were black carbon, silicon, black carbon, and silicon, respectively. DEPs exhibited dose-dependent mutagenicity even at a low dose in Salmonella typhimurium TA 98 and 100 strains in an Ames test for genotoxicity. However, NOC, SOC, and YSD particles did not show any mutagenicity at high doses. The neutral red uptake assay to test cell viability revealed that DEPs showed dose-dependent potent cytotoxicity even at a low concentration. The toxicity of DEPs was relatively higher than that of NOC, SOC, and YSD particles. Therefore, these results indicate that among the four FPs, DEPs showed the highest in vitro biological toxicity. Additional comprehensive research studies such as chemical analysis and in vivo acute and chronic inhalation toxicity tests are necessary to determine and clarify the effects of this air contaminant on human health.