• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.211-215
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• 2003

When Saccharomyces cerevisiae MTY62, a high-RNA content yeast, was cultivated by fed-batch mode feeding molasses and com steep liquor, the cell density less than 45g-DCW/L and the RNA content less than 140mg/g-cell were obtained, indicating that unknown compounds inhibiting the cell growth and RNA accumulation are contained in the molasses. Therefore, in order to obtain higher levels of cell density and RNA content, $Ca^{++}$, $Cu^{++}$and $K^{+}$ ions in molasses were removed by pretreatments of molasses with various agents such as IonClear BigBead, $Na_2$$HPO_4$, $H_2$$SO_4$, citric acid, $K_2$$HPO_4$, and EDT A. Among them, IonClear BigBead, $Na_2$$HPO_4$, and EDTA gave the highest $Ca^{++}$ removal efficiency of about 60-90%. In the batch culture with pretreated molasses, the cell concentration of 18.6g-DCW/I and RNA concentration of 3127 mg/I, maximum specific growth rate of 0.459$h^{-1}$ , and specific consumption rate of reducing sugar of 1.28g-sugar/g-cell-h were obtained, which are about 10%, 17%,47%, and 36% higher levels, respectively, over the batch culture with untreated molasses.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.170-170
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• 1998

In order to discover new types of 5-hydroxytryptamine antagonists, we have devoted our attention to investigating naturally occurring compounds having anti-5HT activity in vitro. Recently, ${\gamma}$-mangostin [1,3,6,7-tetrahydroxy-2,8-bis(3-methyl-2-bytenyl)-9H-xanthen-9-one] from the fruit hull of Garcinia mangostana Linn has been shown to be a selective antagonist for 5-hydroxytryptamine$_{2A}$ receptors in smooth muscle and platelets. It is of interesting that y-mangostin which does not have a nitrogen atom, possesses marked 5-$HT_{2A}$ receptor blocking activity. The present study was undertaken to investigate the effects of ${\gamma}$-mangostin on central 5-HT receptors by using animal behavioural models. Intracerebronventricular injection of ${\gamma}$-mangostin (10-40n mol/mouse) inhibited 5-fluoro-${\alpha}$-methyltryptamin (5-FMT) (45 mg kg$^{-1}$, i.p.)-induced head-twitch response in mice in the presence or absence of citalopram (5-HT-uptake inhibitor). Neither the 5-FMT- nor the 8-hydroxy-2-( di-n-propylamino )tetralin (5-HT$_{1A}$-agonist)-induced 5-HT syndrome (head weaving and hindlimb abduction) was affected by ${\gamma}$-mangostin. The locomotor activity stimulated by 5-FMT through the activation of at-adrenoceptors did not alter in the presence of ${\gamma}$-mangostin. 5-HT-induced inositol phosphates accumulation in mouse brain slices was abolished by ketanserin. ${\gamma}$-Mangostin caused a concentration-dependent inhibition of the inositol phosphates accumulation and the binding of [$^3H$]-spiperone, a specific 5-$HT_{2A}$ receptor antagonist, to mouse brain membranes. Kinetic analysis of the [$^H3$]-spiperone binding revealed that ${\gamma}$-mangostin increased the $_{d}$ value without affecting the $B_{max}$ value, indicating the mode of the competitive nature of the inhibition by ${\gamma}$-mangostin. These results suggest that ${\gamma}$-mangostin inhibits 5-FMT-induced head-twitch response in mice by blocking 5-$HT_{2A}$ receptors not by blocking the release of 5-HT from the central neurone. ${\gamma}$-Mangostin is a promising 5-$HT_{2A}$ receptors antagonist in the central nervous system.m.

• Geophysics and Geophysical Exploration
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• v.27 no.3
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• pp.181-195
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• 2024

This tutorial explains that the static effect in the magnetotelluric (MT) survey is a physical phenomenon caused by charges accumulated on the boundaries of subsurface inhomogeneities. To facilitate understanding of the physical phenomenon, differences between static induction and charge accumulation on the boundary are explained and analyzed with help of schematic illustrations. Subsequently, from the electromagnetic (EM) integral equation formulation, it is clearly shown that the secondary electric field due to charges accumulated on the interface in the presence of the primary field appears as the static effect. Therefore, except in the cases of the layered earth or a two-dimensional earth with transverse magnetic (TM) mode excitation, the static effect always exists in MT responses and further, it is not 'static' but rather frequency dependent. Despite the fact that the static effect is a secondary electric field due to inhomogeneity, inevitable under-sampling in the frequency and spatial domains prevent the effect from being handled properly in numerical inversion. Therefore, considering the practical aspects of the MT survey, which cannot be a continuous measurement covering the entire survey area over a wide frequency band, a three-dimensional (3-D) inversion incorporating the static shift as a constraint with the Gaussian distribution is introduced. To enhance understanding of the integral equation EM modeling, the formulation of the 3-D integral equation and mathematical analyses of the Green tensor and scattering current are described in detail in the Appendix.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.6
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• pp.401-410
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• 2020

In this study, a real-time Tactical UAS position compensation system based on image information developed to compensate for the weakness of location navigation information during GPS signal interference and jamming / spoofing attack is described. The Tactical UAS (KUS-FT) is capable of automatic flight by switching the mode from GPS/INS integrated navigation to DR/AHRS when GPS signal is lost. However, in the case of location navigation, errors accumulate over time due to dead reckoning (DR) using airspeed and azimuth which causes problems such as UAS positioning and data link antenna tracking. To minimize the accumulation of position error, based on the target data of specific region through image sensor, we developed a system that calculates the position using the UAS attitude, EO/IR (Electric Optic/Infra-Red) azimuth and elevation and numerical map data and corrects the calculated position in real-time. In addition, function and performance of the image information based real-time UAS position compensation system has been verified by ground test using GPS simulator and flight test in DR mode.

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.234-239
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• 2001

In order to maximize the RNA accumulation and biomass production is Saccharomyces cerevisiae MTY62, a high-content RNA yeast strain, batch and fed-batch cultures were performed. Among the feeding modes of fed-batch cultures examined, the intermittent feeding mode R\`(IFB-lV), in which 50 ml of 40% molasses and 20% com steep liquor (CSL) solution was intermittently fed for 5 times, resulted in the cell concentration of 33.8 g- dry cell weight/1 and the RNA concentration of 5221 mg-/l, and RNA content of 153 mg-RNA/g-dry cell weight. The constant fed-batch with feeding mode III (CFB-III), in which the feeding rate of 40% molasses and 20% CSL solution was stepwisely decreased from 48 mph (9-13 h), to 24 mph (13-21 h), and to 18 ml/h (21∼ 48 h), gave the highest cell concentration of 42.7 g-dry ceil weigh71 and R7IA concentration of 5536 mg-RNA/1, which were about 2.4-fold and 1.9-fold increased levels, respectively, compared to the results of batch culture. However, the RNA con- tent of 130 mg-RNA/g-dry cell weight of the fed-batch was lower than that of the batch culture (171 mg-RNA/g-dry cell weight) and other fed-batch cultures. When the specific growth rates in the fed-batch cultures were increased, the RNA contents increased. This result indicates that the RNA content is adversely proportional to the cell concen- tration. However, at the same specific growth rate, the RNA content was maintained at higher level in the intermit- tent fed-batch than in the constant fed-batch culture.

• Journal of the Korean earth science society
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• v.24 no.5
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• pp.477-490
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• 2003

Bottom sediments from Youngil Bay, East Coast of Korea, were analyzed for grain composition as well as elemental compositions and total organic carbon (TOC) content in order to investigate the spatial variability and content of metal elements. Grain size distribution of the sediments seems to be controlled by anticlockwise current pattern with bottom topography of the study area. Spatial variability of TOC and all elemental contents reflects those of grain size, but an exception was found in the harbor area (Old-Port): their contents are high in the central part of the bay with the muddy sediment and decrease toward the sand-dominated coastal zone. However, contents of Ca, Sr, K are high in the sand-dominated coastal zone and contents of some heavy metals (Cd, Cu, Zn) are high in the Old-Port area and the mouth of Hyeongsan River. The correlation matrix and R-mode factor analyses reveal that four important factors controlling the distribution of metals in the bay are sediment grain size (or quartz dilution effect), the formation of sulfide minerals associated with decomposition of organic matters under anoxic geochemical environment, calcium carbonate (mainly shell fragments) and coarse-grained feldspar mineral. According to the metal content of labile fraction an CER (concentration enrichment ratio) value, high accumulation of some heavy metals in the harbor area seems to result not formed by early diagenetic processes under anoxic environment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.8
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• pp.755-760
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• 2010

In this study, we mainly focused on the PM (Particulate Matter) emission characteristics of a diesel engine. To analyze particle behavior in the tail-pipe, particle emission was measured on the engine-out (downstream of turbocharger), each upstream and downstream both of DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter). Moreover, particle emission contours on each sampling point were constructed. The reduction efficiency of particle number concentration and mass through the DOC and DPF was studied. Parameters such as EGR (Exhaust Gas Recirculation) and the main injection timing were varied in part load conditions and evaluated using the engine-out emissions. The DMS500 (Differential Mobility Spectrometer) was used as a particle measurement instrument that can measure particle concentrations from 5 nm to 1000 nm. Nano-particles of sizes less than 30 nm were reduced by oxidation or coagulated with solid particles in the tail-pipe and DOC. The DPF has a very high filtration efficiency over all operating conditions except during natural regeneration of DPF.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.469-480
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• 2017

Controversy has surrounded the potential impacts of phytoplankton on the tropical climate, since climate models produce diverse behaviors in terms of the equatorial mean state and El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) amplitude. We explored biophysical impacts on the tropical ocean temperature using an ocean general circulation model coupled to a biogeochemistry model in which chlorophyll can modify solar attenuation and in turn feed back to ocean physics. Compared with a control model run excluding biophysical processes, our model with biogeochemistry showed that subsurface chlorophyll concentrations led to an increase in sea surface temperature (particularly in the western Pacific) via horizontal accumulation of heat contents. In the central Pacific, however, a mild cold anomaly appeared, accompanying the strengthened westward currents. The magnitude and skewness of ENSO were also modulated by biophysical feedbacks resulting from the chlorophyll affecting El $Ni{\tilde{n}}o$ and La $Ni{\tilde{n}}a$ in an asymmetric way. That is, El $Ni{\tilde{n}}o$ conditions were intensified by the higher contribution of the second baroclinic mode to sea surface temperature anomalies, whereas La $Ni{\tilde{n}}a$ conditions were slightly weakened by the absorption of shortwave radiation by phytoplankton. In our model experiments, the intensification of El $Ni{\tilde{n}}o$ was more dominant than the dampening of La $Ni{\tilde{n}}a$, resulting in the amplification of ENSO and higher skewness.

• CELLMED
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• v.2 no.3
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• pp.26.1-26.5
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• 2012

Adverse side-effects and lack of scientific validation of some chemotherapeutic agents prevent the use of many traditional medicines claimed to have anti-cancer effects. Ethanolic extract of Conium maculatum has long been used in traditional and alternative systems of medicine including homeopathy for the treatment of glandular enlargements, cancerous tumours or hard lumps of testicles, prostate, ovaries, breasts and/ or uterus, particularly in the breast. However, if and how it acts still remains scientifically unknown. This study aims to test if Conium extract (CE), used as mother tincture of Conium in homeopathy, has demonstrable anti-cancer potentials without having much cytotoxicity in normal cells. Cytotoxicity of the drug was tested by conducting MTT assay on both normal (peripheral blood mononuclear cells) and HeLa cells. We also evaluated DNA fragmentation and DNA damage by DAPI and diphenylamine assay. The LDH activity assay was done to evaluate the percentages of apoptosis and necrosis. ROS accumulation also was evaluated to pin-point the actual events of apoptosis. Administration of drug clearly demonstrated its anti-cancer potentials as evidenced by the DNA damage analysis. The ROS activity also increased in case of the CE treated cells. LDH data revealed that the mode of cell death was mainly apoptotic and not necrotic. CE appears to induce apoptosis of cancer cells through ROS mediated pathway, and has negligible cytotoxicity against normal cells.

• Computational Structural Engineering
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• v.5 no.3
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• pp.119-126
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• 1992

Most civil engineering structures such as bridges, power plants, and offshore platforms are apt to suffer structural damages over their service lives caused by adverse loadings, such as earthquakes, wind and wave forces. Accumulation of structural damages over a long period of time might cause catastrophic structural failure. Therefore, a methodology for monitoring the structural integrity is essential for assuring the safety of the existing structures. A method for the damage assessment of structures by the second order inverse modal perturbation technique is presented in this paper. Perturbation equation consists of a matrix equation involving matrices of structural changes(stiffness and mass matrix changes) and matrices of modal property changes(natural frequency and mode shape changes). The damages of a structure are represented as changes in the stiffness matrix. In this study, a second order perturbation equation is formulated for the damage assessment of structures, and solved by an iterative procedure. The effectiveness of the proposed method has been investigated through a series of example analysis. The estimated results for the structural damage indicated that the present method yields resonable estimates for the structural changes.