• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.17.2-17.2
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• 2011

Double-walled carbon nanotubes (DWCNTs) were grown with vertical alignment on a Si wafer by using catalytic thermal chemical vapor deposition. This study investigated the effect of pre-annealing time of catalyst on the types of CNTs grown on the substrate. The catalyst layer is usually evolved into discretely distributed nanoparticles during the annealing and initial growth of CNTs. The 0.5-nm-thick Fe served as a catalyst, underneath which Al was coated as a catalyst support as well as a diffusion barrier on the Si substrate. Both the catalyst and support layers were coated by using thermal evaporation. CNTs were synthesized for 10 min by flowing 60 sccm of Ar and 60 sccm of H2 as a carrier gas and 20 sccm of C2H2 as a feedstock at 95 torr and $750^{\circ}C$. In this study, the catalyst and support layers were subject to annealing for 0~420 sec. As-grown CNTs were characterized by using field emission scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, and atomic force microscopy. The annealing for 90~300 sec caused the growth of DWCNTs as high as ~670 ${\mu}m$ for 10 min while below 90 sec and over 420 sec 300~830 ${\mu}m$-thick triple and multiwalled CNTs occurred, respectively. Several radial breathing mode (RBM) peaks in the Raman spectra were observed at the Raman shifts of 112~191 cm-1, implying the presence of DWCNTs, TWCNTs, MWCNTs with the tube diameters 3.4, 4.0, 6.5 nm, respectively. The maximum ratio of DWCNTs was observed to be ~85% at the annealing time of 180 sec. The Raman spectra of the as-grown DWCNTs showed low G/D peak intensity ratios, indicating their low defect concentrations. As increasing the annealing time, the catalyst layer seemed to be granulated, and then grown to particles with larger sizes but fewer numbers by Ostwald ripening.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.236-242
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• 2017

The conversion of marine biomass to renewable energy has been considered an alternative to fossil fuels. Butanol, in particular, can be used directly as a fuel. In this experiment, the brown alga Undaria pinnatifida was selected as a biomass for biobutanol production. Hyper thermal (HT) acid hydrolysis was used as an acid hydrolysis method to produce monosaccharides. The optimal pretreatment conditions for U. pinnatifida were determined as slurry with 10% (w/v) U. pinnatifida content and 270 mM $H_2SO_4$, and heating at $160^{\circ}C$ for 7.5 min. Enzymatic saccharification was carried out with Celluclast 1.5 L, Viscozyme L, and Ultraflo Max. The optimal saccharification condition was 12 U/ml Viscozyme L. Fermentations were carried out for the production of acetone, butanol, and ethanol by Clostridium acetobutylicum KCTC 1724, Clostridium beijerinckii KCTC 1785, and Clostridium tyrobutyricum KCTC 5387. The fermentations were carried out using a pH-control. The optimal ABE fermentation condition determined using C. acetobutylicum KCTC 1724 adapted to 160 g/l mannitol. An ABE concentration of 9.05 g/l (0.99 g/l acetone, 5.62 g/l butanol, 2.44 g/l ethanol) was obtained by the consumption of 24.14 g/l monosaccharide with $Y_{ABE}$ of 0.37 in pH 5.0.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.177-183
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• 2008

The layers of keratinocytes form an acid mantle on the surface of the skin. Herein, we investigated the effects of acidic pH on the membrane current and $[Ca^{2+}]_c$ of human primary keratinocytes from foreskins and human keratinocyte cell line (HaCaT). Acidic extracellular pH ($pH_e{\leq}5.5$) activated outwardly rectifying $Cl^-$ current ($I_{Cl,pH}$) with slow kinetics of voltage-dependent activation. $I_{Cl,pH}$ was potently inhibited by an anion channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS, 73.5% inhibition at 1${\mu}$M). $I_{Cl,pH}$ became more sensitive to $pH_e$ by raising temperature from $24^{circ}C$ to $37^{circ}C$. HaCaT cells also expressed $Ca^{2+}$-activated $Cl^-$ current ($I_{Cl,Ca}$), and the amplitude of $I_{Cl,Ca}$ was increased by relatively weak acidic $pH_e$ (7.0 and 6.8). Interestingly, the acidic $pH_e$ (5.0) also induced a sharp increase in the intracellular [$Ca^{2+}$] (${\triangle}[Ca^{2+}]_{acid}$) of HaCaT cells. The ${\triangle}[Ca^{2+}]_{acid}$ was independent of extracellular $Ca^{2+}$, and was abolished by the pretreatment with PLC inhibitor, U73122. In primary human keratinocytes, 5 out of 28 tested cells showed ${\triangle}[Ca^{2+}]_{acid}$. In summary, we found $I_{Cl,pH}$ and ${\triangle}[Ca^{2+}]_{acid}$ in human keratinocytes, and these ionic signals might have implication in pathophysiological responses and differentiation of epidermal keratinocytes.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.165-173
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• 1992

The present study was carried out to investigate the effects of dopaminergic drugs and the role of specific dopamine(DA) receptors on the release of TSH, $T_4$ and $T_3$. Serum TSH levels (cold-induced, $4{^{\circ}C}$) were determined using RIA(radioimmunoassay) at 30 min after administration of dopamine agonists and antagonists. Serum $T_4$ and $T_3$ levels were detected after these dopaminergic drugs were administered subcutaneously twice a day for a week. The results of the study are summarized as follows : Apomorphine, a nonspecific DA receptor agonist, produced a dose-depedent decrease in serum TSH, $T_4$ and $T_3$ levels. However, only low doses (0.3, 1.0mg/kg) of SKF38393, a specific $D_1$-receptor agonist, produced a decrease in serum lelvels of TSH. I,Y171555, a specific $D_2$-receptor agonist, produced a dose dependent decrease in serum TSH, $T_4$ and $T_3$ levels. However, SCH23390, a specific $D_1$-receptor antagonist, produced a decrease except in serum T levels which were increased dose dependently. High doses (1.0, 3.0mg/kg) of sulpiride, a specific $D_2$-receptor antagonist, made a increase in the serum levels of TSH and $T_3$. The effects of dopaminergic drugs in serum TSH and $T_4$ levels was potentiated by the pretreatment of apomorphine. The overall results of this study suggest that the regulation of TSH, $T_4$ and $T_3$ secretion were mediated via specific $D_1$ and $D_2$ receptor.

• Microbiology and Biotechnology Letters
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• v.9 no.2
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• pp.71-75
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• 1981

Studies were made to optimize the simultaneous hydrolysis-fermentation (SSF) process for the production of ethanol from rice straw. Trichoderma sp. KI 7-2 was selected to produced cellulase by solid culture for SSF. Ethanol production was highest when the SSF process utilized koji culture of the fungus grown on a medium of wheat bran-rice straw 3 : 2 mixture with moisture content of 50% adjusted to pH 4.5 for 7 days as the enzyme source. It was found that pretreatment of the substrate is not necessary. To ferment 1g of rice straw by SSF 2.47 units of cellulase were required, and the initial yeast concentration of 2.5$\times$10$^{7}$ cell/$m\ell$ was found to be sufficient. Optimum pH and temperature for the process were 4.5 and 4$0^{\circ}C$, respectively. It was also found that higher ethanol concentration in the broth can be obtained by the addition of substrate or substrate and enzyme to SSF broth.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.1-10
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• 2003

This study investigated the influence of IRM on marginal microleakage of 5th generation adhesives. Class V cavities with gingival margins in dentin were prepared on both buccal and lingual surfaces of 60 extract-ed human molar teeth. Prepared teeth were randomly divided into six groups. Group 1 and 4 received no temporary restoration with IRM. Group 2 and 5 were covered with IRM mixed at P/L ratio(10g/1g). Group 3 and 6 were covered with IRM mixed at P/L ratio(10g/2g). The temporary restorations were removed mechanically with an ultrasonic scaler after one-week storage in distilled water. The cavities were restored using one of two adhesives and composites ; Single Bond/Filtek Z 250(Croup 1, 2 and 3), UniFil Bond/UniFil F(Group 4, 5 and 6). Following one day storage in distilled water, the restored teeth were thermocycled for 500 cycles(between $5^{\circ}C{\;}and{\;}55^{\circ}C$) and immersed in 2 % methylene blue for dye penetration testing. The results were analysed using Kruskal-Wallis Test, Mann-Whitney and Wilcoxon signed ranked test at a significance level of 0.05. The results of this study were as follows 1. Ranking of mean microleakage scores at the enamel margins was Group 10.05) 4. At the dentin margins, the microleakage of the group not pretreated with IRM was lower than that of the group pretreated with IRM. And the microleakage of UniFil Bond was lower than that of Single Bond. 5. Compared with microleakages between the enamel and dentin margins of each groups, Group 1, 2, 3, 4, 5 and 6 at dentin margin were higher microleakage than those at enamel margin. There were significant difference between enamel and dentin microleakage of Group 2 and 3(p<0.05).

• Journal of Acupuncture Research
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• v.23 no.5
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• pp.23-29
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• 2006

Objectives : The present study was conducted to evaluate the effects of automatically controlled rotating acupuncture (ACRA) on thermal allodynia in neuropathic pain rats, and to examine whether the endogenous opioid system mediates the effects of ACRA. Methods : For the neuropathic surgery, the right superior caudal trunk was resected at the level between S1 and S2 spinal nerves innervating the tail. Two weeks after the nerve injury, ACRA stimulation with 4 different stimulation conditions (i.e., angle and frequency of rotation: 90o+1Hz, 90o+1/4Hz, 360o+/1Hz, and 360o+1/4Hz) was delivered to the Zusanli (ST36) acupoint for 15 min. The behavioral signs of thermal allodynia were evaluated by the tail immersion test (i.e., immersing the tail in cold $(4^{\circ}C)$ or warm $(4^{\circ}C)$ water and measuring the latency to an abrupt tail movement) before and after the stimulation. In an additional set of experiments, we examined the effects of naloxone (opioid Results : ACRA stimulations under all of the conditions above significantly relieved thermal antagonist, 2mg/kg, i.p.) on the action of ACRA stimulation. allodynia. There is no difference in the anti-allodynic effects among the 4 stimulation conditions. In addition, the effect of ACRA on thermal allodynia was reversed by naloxone pretreatment. Conclusion : These results indicate that ACRA stimulations have relieving effects on thermal allodynia in neuropathic pain rats, irrespective of stimulation parameters, and that this is mediated by the endogenous opioid system.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.722-729
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• 1997

The study was undertaken to extend the shelf life of filleted and salted fishes such as mackerel and jacopever. These filleted and salted fishes were dehydrated by dewatering sheet containing sodium polyacrylate resin at $5{\pm}1^{\circ}C$, wrapped with low density polyethylene film, and then stored at $-18{\pm}2^{\circ}C$. During the frozen storage, the change of brown pigment formation, peroxide value, carbonyl value, drip formation content in the cold-osmotic dehydrated fishes after salt dipping were much lower than those of non-dehydrated ones. Moreover, the proteins and Ca-ATPase in the cold-osmotic dehydrated fishes after salt dipping were more stable than those of non-dehydrated ones during frozen storage. It was supposed that the cold-osmotic dehydration pretreatment processing for filleted and salted fishes was useful in improvement of the frozen storage stability.

• Korean Journal of Metals and Materials
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• v.47 no.10
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• pp.675-680
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• 2009

Effects of $85^{\circ}C/85%$ Temperature/Humidity (T/H) treatment conditions on the peel strength of an electroless-plated Ni/polyimide system were investigated from a $180^{\circ}$ peel test. Peel strength between electroless-plated Ni and polyimide monotonically decreased from $37.4{\pm}5.6g/mm$ to $22.0{\pm}2.7g/mm$ for variation of T/H treatment time from 0 to 1000 hrs. The interfacial bonding mechanism between Ni and polyimide appears to be closely related to Ni-O bonding at the Ni/polyimide interface. The decrease in peel strength due to T/H treatment appears to be related to polyimide degradation due to moisture penetration through the interface and the bulk polyimide itself.

• Korean Journal of Microbiology
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• v.37 no.3
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• pp.197-203
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• 2001

An ubiquitous bacterium, Pseudomonar cepacia KH410 was isolated from fresh water plant root and identified. Adsorption of heavy metals of lead, cadmium and copper by this strain was investigated. Optimal conditions foradsorption was 1.0 dry g-biomass, at pH 4.0 and temperature of $40^{\circ}C$. Adsorption equilibrium reached max-imum after 120 min in 1000 mg/l metal solutions. The adsorption capacity (K) of lead was 5.6 times higher thancadmium and 4.0 times higher than that of copper. Adsorption of lead was applicable for Langmuir modelwhereas Freundlich model for cadmium and copper, respectively. Adsorption strength (1/n) of heavy metal ionswere in the order of lead>copper>cadmium. Uptake capacity of lead, cadmium and copper by dried cell was83.2,42.0,65.2 mg/g-biomass, respectively. Effective desorption was induced 0.1 M HCI for lead and 0.1 $HNO_3$ for cadmium and copper. Pretreatment to increase ion strength was the most effective with 0.1 M KOH.Uptake by immobilized cell was 77.8,58.5,71.2 mg/g-biomass for lead, cadmium and copper, respectively. Theimmobilized cell was more effective than ion exchange resin on removal of heavy metals in solution containinglight metals.