• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.7-10
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• 2007

A thick film catalytic gas sensors which can be operated at $142^{\circ}C$ in presence of ultra violet-light emitting diode has been developed to measure hydrogen concentration in 0-5 % range. The sensing material as a combustion catalyst consists of $TiO_{2}$ (5 wt%) and Pd/Pt (20 wt%) supported on $Al_{2}O_{3}$ powder and the reference material to compensate the heat capacity of it in a bridge circuit was an catalyst free $Al_{2}O_{3}$ powder. Platinum heater and sensor materials were formed on the alumina plate by screen printing method and heat treatment. The effect of UV radiation in the presence of photo catalyst $TiO_{2}$ on the sensor sensitivity, response and recovery time has been investigated. The reduction of operating temperature from $192^{\circ}C$ to $142^{\circ}C$ for hydrogen gas sensing property in presence of UV radiation is attributed to the hydroxy radical and superoxide which was formed at the surface of $TiO_{2}$ under UV radiation.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.4
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• pp.413-423
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• 1997

The importance of the kidney in the development of hypertension was first demonstrated by Goldblatt and his colleagues more than fifty years ago. Many hormones and other regulatory factors have been proposed to play a major role in the development of hypertension. Among these factors angiotensia II (ANG II) is closely involved in renal hypertension development since it directly regulates $Na^+$ reabsorption in the renal proximal tubule. Thus the aim of the present study was to examine signaling pathways of low dose of ANC II on the $Na^+$ uptake of primary cultured rabbit renal proximal tubule cells (PTCs) in hormonally defined seum-free medium. The results were as follows: 1) $10^{-11}$ M ANG II has a significant stimulatory effect on growth as compared with control. Alkaline phosphatase exhibited significantly increased activity. However, leucine aminopeptidase and ${\gamma}-glutamyl$ transpeptidase activity were not significant as compared with control. In contrast to $10^{-11}$ M ANG II stimulated $Na^+$ uptake $(108.03{\pm}2.16% of that of control)$, $10^{-9}$ M ANG II inhibited ($92.42{\mu}2.23%$ of that of control). The stimulatory effect of ANG II on $Na^+$ uptake was amiloride-sensitive and inhibited by losartan (ANG II receptor subtype 1 antagonist) and not by PD123319 (ANG II receptor subtype 2 antagonist). 2) Pertussis toxin (PTX) alone inhibited $Na^+$ uptake by $85.52{\pm}3.52%$ of that of control. In addition, PTX pretreatment prevented the AMG II-induced stimulation of $Na^+$ uptake. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), forskolin, and isobutylmethylxanthine (IBMX) alone inhibited $Na^+$ uptake by $88.79{\pm}2.56,\;80.63{\pm}4.38,\;and\;84.47{\pm}4.74%$ of that of control, respectively, and prevented the ANG II-induced stimulation of $Na^+$ uptake. However, $10^{-11}$ M ANG II did not stimulate cAMP production. 3) The addition of 12-O-te-tradecanoylphorbol-13-acetate (TPA, 0.01 ng/ml) to the PTCs produced significant increase in $Na^+$ uptake ($114.43{\pm}4.05%$ of that of control). When ANG II and TPA were added together to the PTCs, there was no additive effect on $Na^+$ uptake. Staurosporine alone had no effect on $Na^+$ uptake, but led to a complete inhibition of ANG II- or TPA-induced stimulation of Na'uptake. ANG II treatment resulted in a $111.83{\mu}4.51%$ increase in total protein kinase C (PKC) activity. In conclusion, the PTX-sensitive PKC pathway is the main signaling cascade involved in the stimulatory effects of ANG II on $Na^+$ uptake in the PTCs.

• Applied Biological Chemistry
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• v.23 no.4
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• pp.228-241
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• 1980

The red ginseng extract and its components were investigated for their activation effects on the growth of Saccharomyces cerevisiae IAM and Saccharomyces formosensis No. 396 IAM. Changes in the number of cells, alcohol production, $CO_2$ evolution, pH and the rate of sugar consumption and of fermentation were compared during growth at $30^{\circ}C$ for 120 hours. The addition of ethanol extract and saponins from red ginseng were found to exihibite a significant increase in all physiological activaties of yeast, and its maximum activites were obtained at 1.5% ethanol extract concentration. The physiological effects of panaxadiol and panaxatriol, two major groups of saponin, were also compared to those of crude saponin and found that the former showed a small increase in physiological changes. However the difference was not significant. The overall contents of ginsenosides of ethanol extract and crude saponin during fermentation were not significantly affected by the growth of roasts, except a small increase in ginsenoside $-Rg_2$ and decrease in -Rd.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.573-584
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• 2003

Bone remodeling results from the combined process of bone resorption and new bone formation which is regulated in part by some of Dexamethasone related proliferation & mineralization of cultured bone cell and polypeptide growth factors such as platelet derived growth factor(PDGF), which has been known to be an important local regulator of bone cell activity and participate in normal bone remodeling. To evaluate the effects of Dex and PDGF on bony healing of calvarial defect in rats, 10 ng/ml PDGF were applied on P group and 10 ng/ml PDGF and $10^7$ M Dex were applied PD group. 4 rats in each group were sacrificed at 7, 14. 21 days after operation respectively, and the tissue blocks were prepared for light microscope with H-E for evaluation of overall healing, with TRAP(tartrate resistant acid phosphatase) for evaluation of osteoclastic activity and with immunohistochemical staining for macrophages. The results were as follows : 1. In all group, healing aspects were progressed from 7 days to 21 days in soft and bony tissue, but complete repair were not observed in bony defect 2. PDGF and control group were showed similar bony healing aspect , but bony healing in combination of PDGF-BB and Dex were observed slower aspect compared to PDGF and control group from early healing times. 3. There were no significant difference on activities of osteoclast and macrophages in bony healing between control and experimental group In conclusion, PDGF were not influenced on bony healing of defect and combination of PDGF-BB and Dex were showed slower healing through early healing times. it was considered that Dex compared to PDGF did influenced on early hone formation factors in healing period

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.1
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• pp.29-36
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• 2011

Nardostachyts chinensis (N. chinensis) belonging to the family Valerianaceae has been used to elicit stomachic and sedative effects. The MAPKs are serine/threonine kinases involved in the regulation of various cellular responses, such as cell proliferation, differentiation and apoptosis. The PKC also plays a key role in regulating the response of hematopoietic cells to both physiological and pathological inducers of proliferation and differentiation. This study investigated the signaling pathways on the U937 cell differentiation induced by N. chinensis. N. chinensis induced the differentiation of U937 cells, as shown by increased of differentiation surface antigen CD11b. Activation of ERK increased time-dependently in differentiation of U937 cells induced by N. chinensis, but activations of JNK and p38 were unaffected. Inhibitor of ERK (PD98059) significantly reduced CD11b expression induced by N. chinensis in U937 cells. In addition, N. chinensis increased protein level of PKC ${\beta}$I and PKC ${\beta}$II isoforms, but the protein level of PKC ${\alpha}$ and PKC ${\gamma}$was constant. PKC inhibitors (GF 109203X and H-7) inhibited U937 cell differentiation and the ERK activation induced by N. chinensis. These results indicated that PKC and ERK may be involved in U937 cell differentiation induced by N. chinensis.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.66-72
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• 2004

PID control has been well used for several decades. For PID algorithms, some tuning methods are used for selecting PID parameters and with these selected parameters, PID control system is designed. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that the designed control system meets the some specifications. For 2 DOF PID controller design this paper presents a linear combinational type of performance indices constituting of index for robust performance, which is obtained by h infinity norm of a weighted complementary sensitivity function, including other time domain indices such as error, energy and changing rate of control input. By numerical methods, the optimal 2 DOF PID parameters are obtained. Therefore various types of 2 degree of freedom PID controllers such as I-PD controller are used so that this two degree of freedom PID controllers may give more desirable output characteristics. Simulations are done with MATLAB m file and mdl files.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.813-818
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• 2008

Various additives were added in small amounts on Ni/YSZ anode of SOFC (solid oxide fuel cell) in order to improve reactivity and to inhibit deactivation due to coke deposition during methane reforming using a low mole ratio steam ($H_2O/CH_4=1.5$) at $800^{\circ}C$. Ni/YSZ catalysts added with various perovskites did not show any improvement but exhibited a gradual decrease in the methane conversion. K-doped Ni/YSZ showed a steady increase and maintenance of the conversion up to 42 hours, after which there was an abrupt deactivation of catalyst owing to potassium loss by volatilization. Addition of 5% of $K_2Ti_2O_5$ on Ni/YSZ showed a stable maintenance of the conversion without K loss, and was able to prevent coke formation during a long time operation. Deactivation of catalyst during the reaction was mainly caused by the accumulation of graphidic carbon on the catalyst surface.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.1
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• pp.47-53
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• 2022

Recently, intelligent packaging of foods has been increasingly developed in response to the growing interest of consumers in checking food quality. Indicators, an important element in intelligent packaging, change color to detect specific substances or indicate food quality changes. Gas indicators can be built into food packaging to detect volatile substances that are released when food quality changes. Ethylene gas is produced as climacteric fruits ripen. Climacteric fruit ripening results from a rapid increase in ethylene production and respiration. In the case of packaged fruits, the ethylene gas concentration in the headspace is closely related to the ripeness of each fruit variety. If an ethylene gas indicator that can be used in fruit packaging is available, the consumer will be able to eat the fruit at the optimal time. In this paper, the characteristics and pros and cons of the ethylene gas indicators developed so far were analyzed by reviewing various types of indicators such as metal reduction-based indicator, fluorescence-based indicator, pH indicator-based indicator, and liposome-based indicator.

• The Korean Journal of Mycology
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• v.45 no.3
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• pp.212-223
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• 2017

To screen for potent anti-inflammatory compound-producing yeasts, we evaluated nitric oxide production inhibitory activities in RAW 264.7 macrophage cells using cell-free extracts from 182 non-pathogenic yeasts. Rhodotorula graminis YJ36-1 and Meyerozyma guilliermondii YJ34-2 showed high inhibitory activities of 57.4% and 47.0%, respectively. The microbiological characteristics of these yeasts were investigated. Rhodotorula graminis YJ36-1 formed ascospores and pseudomycelium. This species grew well at $25^{\circ}C$ in yeast extract-peptone-dextrose (YPD) medium, vitamin-free medium, and 5% NaCl-containing YPD medium. Meyerozyma guilliermondii YJ34-2 was an asporogenous yeast and did not form pseudomycelium. This strain also grew well at $30^{\circ}C$ in YPD medium, vitamin-free medium, and 5% NaCl-containing YPD medium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1915-1923
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• 2013

The aim of this study is carried out to evaluate the fermentation characteristics and increased functionality when doenjang was prepared with bamboo salts. Grain type mejus were fermented with mixed starter cultures of Aspergillus oryzae, Bacillus subtilis, and Lactococcus lactis. These mejus were mixed with different kinds of salts-purified salt (PD), sea salt (SD), one-time baked bamboo salt ($1{\times}BD$), three-time baked bamboo salt ($3{\times}BD$), and nine-time baked bamboo salt ($9{\times}BD$)- when doenjangs were prepared. For doenjang fermentation period of 8 weeks at $37^{\circ}C$, the fermentation characteristics of all the groups were compared. The amino type nitrogen content and enzyme activities (protease and ${\alpha}$-amylase) in the samples were significantly increased. In DPPH radical scavenging activities and hydroxyl radical scavenging activities, $9{\times}BD$ (47% and 69%) showed the highest scavenging activities compared to PD (40% and 49%), SD (42% and 57%), $1{\times}BD$ (42% and 64%) and $3{\times}BD$ (45% and 65%) (P<0.05). The anticancer effects of doenjang in HT-29 cancer cells indicated all the groups, especially doenjang prepared with bamboo salts were higher than the others (P<0.05). Apoptosis related genes of Bax and Bcl-2, as well as inflammation related genes of iNOS and COX-2 were regulated by the treatment of doenjangs in HT-29 cancer cells. SD, $1{\times}BD$, $3{\times}BD$, and $9{\times}BD$ increased the expression level of Bax and decreased the expression level of Bcl-2, iNOS, and COX-2. These results suggest that sea salt and bamboo salt especially bamboo salt could improve fermentation characteristics and functionality of doenjang and play an important role in regulating apoptosis and inflammation related genes in cancer cells.