• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.199-208
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• 2016

We present photometric results of the δ Sct star V1162 Ori, which is extensively monitored for a total of 49 nights from mid-December 2014 to early-March 2015. The observations are made with three KMTNet (Korea Microlensing Telescope Network) 1.6 m telescopes installed in Chile, South Africa, and Australia. Multiple frequency analysis is applied to the data and resulted in clear detection of seven frequencies without an alias problem: five known frequencies and two new ones with small amplitudes of 1.2-1.7 mmag. The amplitudes of all but one frequency are significantly different from previous results, confirming the existence of long-term amplitude changes. We examine the variations in pulsation timings of V1162 Ori for about 30 years by using the times of maximum light obtained from our data and collected from the literatures. The O − C (Observed minus Calculated) timing diagram shows a combination of a downward parabolic variation with a period decreasing rate of (1/P)dP/dt = −4.22 × 10⁻⁶ year⁻¹ and a cyclic change with a period of about 2780 days. The most probable explanation for this cyclic variation is the light-travel-time effect caused by an unknown binary companion, which has a minimum mass of 0.69 M_⊙. V1162 Ori is the first δ Sct-type pulsating star of which the observed fast period decrease can be interpreted as an evolutionary effect of a pre-main sequence star, considering its membership of the Orion OB 1c association.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.37-37
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• 2015

dsRNA was found in malformed cultures of Lentinula edodes strain FMRI0339, one of the three most popular sawdust cultivated commercial strains of shiitake, and was also found in healthy-looking fruiting bodies and actively growing mycelia. Cloning of the partial genome of the dsRNA revealed the presence of the RdRp sequence of a novel L. edodes mycovirus (LeV), and sequence comparison of the cloned amplicon showed an identical sequence to known RdRp genes of LeV found in strain HKA. The meiotic stability of dsRNA was examined by measuring the ratio of the presence of dsRNA among sexual monokaryotic progeny. More than 40% of the monokaryotic progeny still contained the dsRNA, indicating the persistence of dsRNA during sexual reproduction. Comparing the mycelia growth of monokaryotic progeny suggested that, although variations in the growth rate existed among progeny and virus infection was observed in highly actively growing progeny, there appeared to be a tendency toward a lower frequency of virus incidence in actively growing progeny. This study attempted to cure the edible mushroom L. edodes strain FMRI0339 of the L. edodes mycovirus (LeV) in order to obtain an isogenic virus-free fungal strain as well as a virus-infected strain for comparison. Mycelial fragmentation, followed by being spread on a plate with serial dilutions resulted in a virus-free colony. Viral absence was confirmed with gel electrophoresis after dsRNA-specific virus purification, Northern blot analysis, and PCR using reverse transcriptase (RT-PCR). Once cured, all of fungal cultures remained virus-free over the next two years. Interestingly, the viral titer of LeV varied depending on the culture condition. The titer from the plate culture showed at least a 20-fold higher concentration than that grown in the liquid culture. However, the reduced virus titer in the liquid culture was recovered by transferring the mycelia to a plate containing the same medium. In addition, oxygen-depleted culture conditions resulted in a significant decrease of viral concentration, but not to the extent seen in the submerged liquid culture. Although no $discernable phenotypic changes in colony morphology were observed, virus-cured strains showed significantly higher growth rates and mycelial mass than virus-infected strains. We were also explored effects of LeV on fruiting body formation and mushroom yield. The fruiting body formation yield of virus-free L. edodes was larger than virus-infected L. edodes. These results indicate that LeV infection has a deleterious effect on mycelial growth and fruiting body formation. In addition, we have been investigated host-parasite interaction between L. edodes and its mycovirus interaction to study viral mechanism by establishment of proteomics.

• Plant Resources
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• v.5 no.1
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• pp.29-44
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• 2002

In this study, plant regeneration through in vitro culture from plantlet stems of Yooja (C. junos Sieb.) and trifoliate orange (P. trifoliata Rafin.) was attempted to make mass-production system of virus-free plants having the same genotype with mother plant. In order to investigate physiological change depending on the developmental stage of plant regeneration, the changes of total protein, peroxidase and esterase activity and their isozyme patterns as well were examined in 1/2 MS medium. The results are as follows : 1. The MS medium for the optimal callus induction and shoot formation was utilized. The medium was supplemented either with 2,4-D and Kinetin or with BA and NAA. The optimal concentrations were the combination of 1.0mg/ 2,4-D +0.3mg/ Kinetin and 1.0mg BA +0.3mg NAA in callus induction and shoot formation, respectively. 2. For the plant regeneration from somatic embryos, 1/2 MS medium was used with supplements of growth regulators (free, 1.0mg/ IBA +1.0mg/ BA ,0.5mg/ IBA +0.5mg/ BA). Shooting and rooting were the best in the treatment of 0.5mg/ IBA and 0.5mg/ BA combination. 3. The total protein content has a tendency of increase with the developmental stage of embryo, but it was decreased at the plantlet. Also it was the highest at 8 and 6 weeks stage in C. junos Sieb. and P. trioliata Rafin, respectively. In the SDS-PAGE pattern of protein, C. junos Sieb. showed bands of 29.0 and 40kDa at 10 weeks. The 45,66 and 97.4 kDa bands at 10 weeks of culture were shown in P. trifoliata Rafin. 4. The highest esterase activity was shown at the 6 and 8 weeks of culture in C.junos Sieb. and P. trifoliata Rafin.., respectively. 5. Esterase isozyme patterns were shown difference according to the developmental stage. In C. junos Sieb. a new band was observed at pl 7.7 following 4 weeks culture. On the other hand, new bands in P. trifoliata Rafin. were observed at pl 7.5~6.5 following 4 and 6 weeks culture, respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.68.1-68.1
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• 2012

The best part of graphene is - charge-carriers in it are mass less particles which move in near relativistic speeds. Comparing to other materials, electrons in graphene travel much faster - at speeds of $10^8cm/s$. A graphene sheet is pure enough to ensure that electrons can travel a fair distance before colliding. Electronic devices few nanometers long that would be able to transmit charge at breath taking speeds for a fraction of power compared to present day CMOS transistors. Many researches try to check a possibility to make it a perfect replacement for silicon based devices. Graphene has shown high potential to be used as interconnects in the field of high frequency electrical devices. With all those advantages of graphene, we demonstrate characteristics of electrical and optical properties of graphene such as the effect of graphene geometry on the microwave properties using the measurements of S-parameter in range of 500 MHz - 40 GHz at room temperature condition. We confirm that impedance and resistance decrease with increasing the number of graphene layer and w/L ratio. This result shows proper geometry of graphene to be used as high frequency interconnects. This study also presents the optical properties of graphene oxide (GO), which were deposited in different substrate, or influenced by oxygen plasma, were confirmed using different characterization techniques. 4-6 layers of the polycrystalline GO layers, which were confirmed by High resolution transmission electron microscopy (HRTEM) and electron diffraction analysis, were shown short range order of crystallization by the substrate as well as interlayer effect with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups on its layers. X-ray photoelectron Spectroscopy (XPS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation, and Fourier Transform Infrared spectroscopy (FTIR) and XPS analysis shows the changes in oxygen functional groups with nature of substrate. Moreover, the photoluminescent (PL) peak emission wavelength varies with substrate and the broad energy level distribution produces excitation dependent PL emission in a broad wavelength ranging from 400 to 650 nm. The structural and optical properties of oxygen plasma treated GO films for possible optoelectronic applications were also investigated using various characterization techniques. HRTEM and electron diffraction analysis confirmed that the oxygen plasma treatment results short range order crystallization in GO films with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups. In addition, Electron energy loss spectroscopy (EELS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation and XPS analysis shows that epoxy pairs convert to more stable C=O and O-C=O groups with oxygen plasma treatment. The broad energy level distribution resulting from the broad size distribution of the $sp^2$ clusters produces excitation dependent PL emission in a broad wavelength range from 400 to 650 nm. Our results suggest that substrate influenced, or oxygen treatment GO has higher potential for future optoelectronic devices by its various optical properties and visible PL emission.

• Journal of Korean Medicine for Obesity Research
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• v.4 no.1
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• pp.45-54
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• 2004

Objective: To evaluate the effect of Ephedra Sinica and Evodia Rutaecarpa on resting metabolic rate(RMR), weight and body composition in obese women during low-calorie diet. Methods: We recruited 90 healthy premenopausal women$(body\;mass\;index{\geq}25kg/m^2)$ and randomly assigned to three groups(ephedra group, evodia group and placebo group). Subjects were administered Ephedra Sinica(6g twice a day) or Evodia Rutaecarpa(6g twice a day) or placebo in a double-blind fashion and participated in low-calorie diet for 8 weeks. Resting metabolic rate and body composition were measured at baseline, 4 and 8 weeks. Results: RMR change for 4 weeks was significantly higher in the ephedra group compared with the placebo group(p<.05). But the change for 8 weeks was not significant and the Evodia group showed no significant RMR change. Weight and percent body fat changes for 4 weeks and 8 weeks were significantly higher than the placebo group in the ephedra group(p<.05), but the Evodia group didn't show significant level. Conclusions: This study supports and emphasizes the benefits of herbal medicine in maintaining or increasing RMR during low-calorie diet. Especially Ephedra treatment was effective on significant maintainment of RMR, loss of weight and percent body fat(P<.05).

• Journal of Life Science
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• v.14 no.4
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• pp.547-552
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• 2004

The present study was carried out to investigate the potential acute toxicity of amitraz by a single subcutaneous dose in beagle dogs. The test chemical was administered subcutaneously to male beagle dogs at dose levels of 0, 2, 10, or 50 mg/kg. Mortalities, clinical findings, and body weight changes were monitored for the 14-day period following the administration. At the end of 14-day observation period, hematology, serum biochemistry, and gross postmortem examinations were examined. A single dog in the 50 mg/kg group was found dead on day 3 after treatment and the other two dogs in the group were sacrificed because of the severe clinical signs on day 7 after treatment. Treatment related clinical signs, including anorexia, edema, mass and abscess formation in the injection sites, depression, vomiting, lacrimation, decreased locomotor activity, ataxia, recumbency, paresis in the limbs, and/or moribundity were observed in all treatment groups in a dose-dependent manner. Decreased or suppressed body weight gain was also observed dose-dependently in all treated groups. In autopsy, dead animals in the 50 mg/kg group showed muscular hemorrhage and inflammation in the injection sites and congestion in the liver and kidney. The terminal sacrificed animals in the 10 mg/kg group also exhibited muscular hemorrhage and inflammation in the injection sites. Whereas, no treatment related effects on hematology and serum biochemistry were observed on day 14 after treatment at any dose tested. On the basis of the results, it was concluded that a single subcutaneous injection of amitraz to beagle dogs resulted in increased incidence of abnormal clinical signs and death, decreased body weight, and increased incidence of abnormal gross findings. In the experimental conditions, the $LD_{50}$value of amitraz was 22.3 mg/kg (95% confidence limit not specified) and the no-observed-adverse-effect level (NOAEL) was considered to be below 2 mg/kg for male dogs.

• Journal of Microbiology
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• v.45 no.5
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• pp.460-465
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• 2007

This study was carried out in order to investigate the potential of using plant oils derived from Leptospermum petersonii Bailey and Syzygium aromaticum L. Merr. Et Perry as natural antifungal agents. The antifungal effects of essential oils at concentrations of 0.05, 0.1, 0.15, and 0.2 mg/ml on the dermatophytes Microsporum canis (KCTC 6591), Trichophyton mentagrophytes (KCTC 6077), Trichophyton rubrum (KCCM 60443), Epidermophyton floccosum (KCCM 11667), and Microsporum gypseum were evaluated using the agar diffusion method. The major constituents of the active fraction against the dermatophytes were identified by gas chromatography-mass spectrometry and high-performance liquid chromatography analysis. The antifungal activities of S. aromaticum oil (clove oil) against the dermatophytes tested were highest at a concentration of 0.2mg/ml, with an effectiveness of more than 60%. Hyphal growth was completely inhibited in T. mentagrophytes, T. rubrum, and M. gypseum by treatment with clove oil at a concentration of 0.2 mg/ml. Eugenol was the most effective antifungal constituent of clove oil against the dermatophytes T. mentagrophytes and M. canis. Morphological changes in the hyphae of T. mentagrophytes, such as damage to the cell wall and cell membrane and the expansion of the endoplasmic reticulum, after treatment with 0.11 mg/ml eugenol were observed by transmission electron microscopy (TEM). At a concentration of 0.2 mg/ml, L. petersonii oil (LPO) was more than 90% effective against all of the dermatophytes tested, with the exception of T. rubrum. Geranial was determined to be the most active antifungal constituent of L. petersonii oil. Taken together, the results of this study demonstrate that clove and tea tree oils exhibited significant antifungal activities against the dermatophytes tested in this study.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.29-36
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• 2002

Epimedium koreanum Nakai(EKN) has traditionally been well-known as a herbal medicine for the promotion of stamina and the improving sexual activity of human in oriental countries including Korea and China. The aim of this study was to investigate the effect of dietary supplementation of EKN water-extract(0.025%,w/v) on age-related change of xenobiotic metabolizing system in rat liver. Long-term supply of the EKN extract to rats did not induce any discernible signs. However, the mass of liver and kidney were slightly increased by the dietary supplementation. Level of cytochrome P450, NADPH cytochrome P450 reductase, P450 dependent ethoxycoumarin O-deethylase benzphetamine N-demethylase and glutathione-S-transferase in liver were decreased with age, but, these activities in 24 months of age were declined more in rats supplied with EKN extract. Level of cytochrome b5 and NADH-cytochrome b5 reductase were also decreased with age, however, there was no significant difference between with and without EKN extract. These results indicate that long-term supplementation of EKN extract to rats from weaning to 24 months may be a burden on the liver function in old age, and may aggregate the decline of xenobiotic metabolizing enzymes activities in old age.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.2 s.25
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• pp.17-28
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• 2003

Since 1970s, Seoul Metropolitan Area has been growing in physical and demographic aspect. A number of new urban fringes, New City, had been particularly developed from the early of 1990s. To examine the urban growth, the population density maps are generally used to the efficient urban management tool. The density maps from political boundaries, however, were traditionally used to estimate an urban concentration, there is problems to apply directly to urban management decision making due to (i) the abrupt changes between boundaries and (ii) the inclusion of green areas and forests in these areas. The mass-preserving interpolation method, the Pycnophylactic interpolation, could provide more realistic density maps. In addition, the classified urban areas from satellite images corresponding years would turn out to be more reliable results since populations were only applied to urbanized areas. Even though the Pyconophylactic method makes the density larger, it would be useful to produce a general urban growth trend at large scale. Consequently, four different density maps are compared and reviewed for this study, and the cross-sectional analysis provided to glimpse of population density around the city center.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.151-161
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• 2012

An intensive analysis of 148 timings of V700 Cyg was performed, including our new timings and 59 timings calculated from the super wide angle search for planets (SWASP) observations, and the dynamical evidence of the W UMa W subtype binary was examined. It was found that the orbital period of the system has varied over approximately $66^y$ in two complicated cyclical components superposed on a weak upward parabolic path. The orbital period secularly increased at a rate of $+8.7({\pm}3.4){\times}10^{-9}$ day/year, which is one order of magnitude lower than those obtained by previous investigators. The small secular period increase is interpreted as a combination of both angular momentum loss (due to magnetic braking) and mass-transfer from the less massive component to the more massive component. One cyclical component had a $20.^y3$ period with an amplitude of $0.^d0037$, and the other had a $62.^y8$ period with an amplitude of $0.^d0258$. The components had an approximate 1:3 relation between their periods and a 1:7 ratio between their amplitudes. Two plausible mechanisms (i.e., the light-time effects [LTEs] caused by the presence of additional bodies and the Applegate model) were considered as possible explanations for the cyclical components. Based on the LTE interpretation, the minimum masses of 0.29 $M_{\odot}$ for the shorter period and 0.50 $M_{\odot}$ for the longer one were calculated. The total light contributions were within 5%, which was in agreement with the 3% third-light obtained from the light curve synthesis performed by Yang & Dai (2009). The Applegate model parameters show that the root mean square luminosity variations (relative to the luminosities of the eclipsing components) are 3 times smaller than the nominal value (${\Delta}L/L_{p,s}{\approx}0.1$), indicating that the variations are hardly detectable from the light curves. Presently, the LTE interpretation (due to the third and fourth stars) is preferred as the possible cause of the two cycling period changes. A possible evolutionary implication for the V700 Cyg system is discussed.