• Korean Journal of Microbiology
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• v.29 no.2
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• pp.130-135
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• 1991

The effects of a herbicide butachlor[2-chloro-2', 6'-diethyl-N-(butoxymethyl) acetanilide] on the growth of the purple non-sulfur bacteria were investigated. The butachlor inhibited the growth of all species tested by 18-51%, except Rhodospirillum rubrum at concentrations of M, which would be field capacity. The photosynthetic growth rate of the species in the presence of butachlor was influenced by the nitrogen source. Cultures supplied with (NH&S04 showed a somewhat higher growth rate than those fixing dinitrogen, but they were more susceptible to butachlor (26-51%). On the contrary, butachlor enhanced the growth rate of Rhodospirillum rubrum in nitrogen gas conditions. When the culture was performed in medium with butachlor as the carbon source, the cells of fixing dinitrogen showed a higher exhaustion of butachlor than those supplemented with (N&)2S04, which exhaustion was examined by a decrease of the major absorbance at 213 nm and 260 nm. The exhaustion of butachlor as the carbon source had relation with the growth of the cells. The alkalization of culture supplemented with nitrogen gas was found in the cells treated with butachlor or untreated. The butachlor affected the carotenoid region but bacteriochlorophyll remained unaffected.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.765-771
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• 2012

$SF_6$ gas has been used as arc quenching and insulating medium for high and extra high voltage switching devices due to its high dielectric strength, its excellent arc-quenching capabilities, its high chemical stability and non toxicity. Despite of its significant contributions, the gas was classified as one of the greenhouse gas in the Kyoto Protocol. Thus, many researches are conducted to find out the replacement materials and to develop the $SF_6$ gas useless electrical equipment. This paper describes experiments on the temperature change-related breakdown characteristics of $SF_6$ gas ($SF_6$) and $SF_6$ liquid ($LSF_6$) in a model GIS(Gas-Insulated Switchgear) chamber in order to show the possibility of more stable and safe usages of $SF_6$ gas. The breakdown characteristics are classified into three stages, namely the gas stage of $SF_6$ according to Paschen's law, the coexisting stage of $SF_6$ gas with liquid in considerable deviation at lower temperature, and the stage of $LSF_6$ and remaining air. The result shows that the ability of the $LSF_6$ insulation is higher than the high-pressurized $SF_6$. Moreover, it reveals that the breakdown characteristics of $LSF_6$ are produced by bubble-formed $LSF_6$ evaporation and bubbles caused by high electric emission and the corona. In addition, the property of dielectric breakdown of $LSF_6$ is determined by electrode form, electrode arrangement, bubble formation and movement, arc extinguishing capacity of the media, difficulty in corona formation, and the distance between electrodes. The bubble formation and flow separation phenomena were identified for $LSF_6$. It provides fundamental data not only for $SF_6$ gas useless equipment but also for electric insulation design of high-temperature superconductor and cryogenic equipment machinery, which will be developed in future studies.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.249-253
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• 2004

The type of air lift bioreactor affected the root growth in ginseng adventitious root cultures. Among bioreactors used in this experiment, bulb type bubble bioreactor (BU) was the best to increase root growth (41.92 g dry weight). The kLa value representing the oxygen transfer capacity from medium to explants (6.98 h$^{-1}$ ) in BU with 5 cm bubble column was higher than other bioreactors. On the other hand, cylindric tube bioreactor (CT) without bubble column resulted in minimum root growth (38.55 g dry weight) and kLa value (5.25 h$^{-1}$ ). Furthermore, the root growth (50.30 g dry weight) in BU with 10 cm bubble column more increased than 5 cm bubble column. However, the kLa value do not affected the secondary metabolite such as ginsenosides. These results show that the bubble column in air lift bioreactor increase kLa value and increased kLa value stimulate the growth of ginseng adventitious roots.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.4
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• pp.161-170
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• 2011

Quercetin is one of the most distributed flavonoids in the plant kingdom and occurs naturally in a wide range of fruits and vegetables. This study was undertaken to determine whether quercetin exerts beneficial effect against necrotic and apoptotic cell death induced by hydrogen peroxide ($H_2O2$) in intestinal cells using the human-derived cultured T84 colonic epithelial cell line. Necrotic cell death was induced by exposing cells to 0.5 mM $H_2O_2$ for 2 h and apoptosis was induced by incubating cells in normal culture medium for 18 h following exposure of cells to 0.5 mM $H_2O2$ for 2 h. Cell viability was evaluated by the trypan blue exclusion assay and apoptosis was assessed by Hoechst 33258 staining and flow cytometry. $H_2O_2$ induced necrotic cell death in a time and dose-dependent fashion. Both necrotic and apoptotic cell deaths were not prevented by the antioxidants N,N'-diphenyl-p-phenylenediamine(DPPD) and Trolox, whereas both cell deaths induced by the organic hydroperoxide t-butylhydroperoxide (tBHP) were prevented by DPPD, suggesting that $H_2O_2$ induces cell death through a lipid peroxidation-independent mechanism. $H_2O2$-induced necrotic death was prevented by deferoxamine and 3-aminobenzamide, while the apoptotic cell death was not affected by these agents. Quercetin prevented both necrotic and apoptotic cell deaths induced by $H_2O_2$ in a dose-dependent manner. $H_2O_2$ caused activation of poly (ADP-ribose) polmerase (PARP), which was inhibited by deferoxamine, 3-aminobenzamide, and quercetin, but not DPPD. These results indicate that quercetin inhibits both necroticand apoptotic deaths of T84 cells. The anti-necrotic effect of quercetin may be attributed to its iron chelator activity rather than a direct $H_2O_2$ scavenging capacity and antioxidant. The present study suggests that quercetin may play a therapeutic role in the treatment of human gastrointestinal diseases mediated by oxidants.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2018-2030
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• 2015

A two stage ac drive configuration consisting of a single-phase line commutated rectifier and a three-phase voltage source inverter (VSI) is very common in low and medium power applications. The deterministic pulse width modulation (PWM) methods like sinusoidal PWM (SPWM) could not be considered as an ideal choice for modern drives since they result mechanical vibration and acoustic noise, and limit the application scope. This is due to the incapability of the deterministic PWM strategies in sprawling the harmonic power. The random PWM (RPWM) approaches could solve this issue by creating continuous harmonic profile instead of discrete clusters of dominant harmonics. Insufficient filtering at dc link results in the amplitude distortion of the input dc voltage to the VSI and has the most significant impact on the spectral errors (difference between theoretical and practical spectra). It is obvious that the sprawling effect of RPWM undoubtedly influenced by input fluctuation and the discrete harmonic clusters may reappear. The influence of dc link fluctuation on harmonics and their spreading effect in the VSI remains invalidated. A case study is done with four different filter capacitor values in this paper and results are compared with the constant dc input operation. This paper also proposes an ingenious RPWM, a ripple dosed sinusoidal reference-random carrier PWM (RDSRRCPWM), which has the innate capacity of suppressing the effect of input fluctuation in the output than the other modern PWM methods. MATLAB based simulation study reveals the fundamental component, total harmonic distortion (THD) and harmonic spread factor (HSF) for various modulation indices. The non-ideal dc link is managed well with the developed RDSRRCPWM applied to the VSI and tested in a proto type VSI using the field programmable gate array (FPGA).

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.250-258
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• 2007

Typography is the combination of language of formative art. It is indeed the core means of human communication through understanding of language and formative values. Studies began on introduction of various techniques to overcome the phenomenon of the 'reaction of language', which appears as an impediment in delivery and sharing of information as the most fundamental roles. Successively, mobile printing types more readable and effective in delivering of meanings have been developed, thus widely distributed for general use. However, although such printing types might be easily used in image and digital media, such as in computer monitors, screens and mobile phone LCDs, etc., it is in fact difficult to use these printing types in printed surfaces, the traditional medium of information delivery, or in sign systems frequently encountered in our surrounding environment. As a solution for this, it is intended to create an effect of communication closer to dynamic typography expression by approaching visual message delivery system from the essence and substance of the color application, which corresponds to the visual spatial expression effect, the core element of expression in dynamic typography to possess significantly more powerful effect in terms of both message delivery capacity and readability than the conventional means of static typography.

• Steel and Composite Structures
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• v.27 no.5
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• pp.537-543
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• 2018

Mechanical shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface in composite beams. Steel pipe as a new shear connector is proposed in this research and its performance to achieve composite strength is investigated. Experimental monotonic push-out tests were carried out for this connector. Then, a nonlinear finite element model of the push-out specimens is developed and verified against test results. Further, the finite element model is used to investigate the effects of pipe thickness, length and diameter on the shear strength of the connectors. The ultimate strengths of these connectors are reported and their respective failure modes are discussed. This paper comprises of the push-out tests of ten specimens on this shear connector in both the vertical and horizontal positions in different reinforced concretes. The results of experimental tests are given as load-deformation plots. It is concluded that the use of these connectors is very effective and economical in the medium shear demand range of 150-350 KN. The dominant failure modes observed were either failure of concrete block (crushing and splitting) or shear failure of pipe connector. It is shown that the horizontal pipe is not as effective as vertical pipe shear connector and is not recommended for practical use. It is shown that pipe connectors are more effective in transferring shear forces than channel and stud connectors. Moreover, based on the parametric study, a formula is presented to predict the pipe shear connectors' capacity.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1267-1272
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• 2005

The effect of various moisture contents of fresh forage on the change in nitrogen (N) fractions, in vitro ruminal N degradability, and the subsequent N utilization of silage in sheep were evaluated. Orchardgrass (Dactylis glomerata L.) with high (HM, 76%), medium (MM, 65%) and low (LM, 40%) moisture contents were ensiled into silos of 120 L capacity for 120 days. A nitrogen balance trial was conducted using a 4${\times}$4 Latin square design consisting of four dietary treatments (i.e. fresh forage, HM, MM and LM silages) and four wethers. With respect to N fractions, fraction 1 (buffer solution soluble N), fraction 2 (buffer solution insoluble N-neutral detergent insoluble N), fraction 3 (neutral detergent insoluble N-acid detergent insoluble N), and fraction 4 (acid detergent insoluble N) were determined. The proportion of fraction 1 in silages tended to decrease, while the in vitro ruminal degradability of insoluble N increased (p<0.05) with lower moisture contents at ensiling. Consequently, nitrogen utilization in sheep tended to improve as the moisture content of ensiled grass was decreased, with a negative correlation (p<0.01) between urinary N and the in vitro ruminal degradability of insoluble N. The averaged N retentions for HM, MM, and LM silage treatments were 59, 73 and 79% of that for fresh forage, respectively.

• Journal of Intelligence and Information Systems
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• v.10 no.1
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• pp.47-63
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• 2004

Today, there are several markets in cyber space where companies trade electronically due to the development of Information Technology. On the other hand, the most important thing in trades is negotiation. So, in order to support current business practices as well as new ones on the Internet, electronic commerce systems need an ability to negotiate. In this paper, proposed is a method by which a seller can be supported by an agent which plays a role in negotiation process among small and medium companies especially injection mold manufacturer. If the manufacturing capacity cannot afford to produce all orders, the manufacturer may want to extend due dates and the buyers may want to discount prices. The negotiation agent discussed in this paper cooperates with the schedule agent to get due-date information, and performs a role in one (seller)-to-many (buyer) negotiation processes.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.356-362
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• 2010

Ceramide is important not only for the maintenance of the barrier function of the skin but also for the water-binding capacity of the stratum corneum. Although the exact role of ceramide in the human skin is not fully understood, ceramide has become a widely used ingredient in cosmetic and pharmaceutical industries. Compared with other microorganisms, yeast is more suitable for the production of ceramide because yeast grows fast and is non-toxic. However, production of ceramide from yeast has not been widely studied and most work in this area has been carried out using Saccharomyces cerevisiae. Regulating the genes that are involved in sphingolipid synthesis is necessary to increase ceramide production. In this study, we investigated the effect of the genes involved in the synthesis of ceramide, lcb1, lcb2, tsc10, lac1, lag1, and sur2, on ceramide production levels. The genes were cloned into pYES2 high copy number vectors. S. cerevisiae was cultivated on YPDG medium at $30^{\circ}C$. Ceramide was purified from the cell extracts by solvent extraction and the ceramide content was analyzed by HPLC using ELSD. The maximum production of ceramide (9.8 mg ceramide/g cell) was obtained when the tsc10 gene was amplified by the pYES2 vector. Real-time RT-PCR analysis showed that the increase in ceramide content was proportional to the increase in the tsc10 gene expression level, which was 4.56 times higher than that of the control strain.