• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.209-215
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• 1991

The propose of this study was to evaluate the effect of the variuos antiseptic solutions and distilled water on physical properties of endodontic gutta-percha cone. The antiseptic solutions were 70% isoprophyl alcohol, 5% NaOCl and 2.5% NaOCl, as control gutta-percha cones, did not stored antiseptic solution was used. Observation periods were 1, 5, 10, 20, and 30 days. In each group,. the 15 gutta-percha cones used. A tensile strength and elongation rate measurements were performed with Instron (Instron 4501), cross - head speed was set 10 inch / min. The data were statistically analyzed and the results were as followed. 1. The tensile strength of the gutta-percha cones, stored in distilled water, were slightly decreased (p<0.05). Elongation rate was not significantly different 2. The tensile strength of the gutta-percha cones, stored in 70% isopropyl alcohol, were increased (p<0.01) except 1 day group. 3. The tensile strength of the gutta-percha cone, stored in 2.5% NaOCl, were decreased (p<.0.05). Elongation rate significantly decreased (p<0.01). 4. The tensile strength of the gutta-percha cone, stored in 5% NaOCl, were decreased (p<0.05). Elongation rate significantly decreased (p<0.01). These results showed that the changes of physical properties (tensile strength and elongation rate) in gutta-percha cone were developed after a day' when gutta-percha cone were stored at 70% isopropyl alcohol, 2.5% or 5% NaOCl. So, It was concluded that gutta-percha cone must have been used at least within one day, when they were stored at the above antiseptics. I thought that the study of substantial effects on endodontic treatment due to changes of physical properties in gutta-percha cone will be needed.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.711-717
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• 2018

Human epidermal growth factor (hEGF) can stimulate the division of various cell types and has potential clinical applications. Since the protein contains three intra-molecular disulfide bonds, the high expression of active hEGF in Escherichia coli has not been well researched, We fused the hEGF gene with a small ubiquitin-related modifier gene (SUMO) by synthesizing an artificial SUMO-hEGF fusion gene that was highly expressed in E. coli (DE3) strain. The optimal expression level of the soluble fusion protein, SUMO-hEGF with IPTG (Isopropyl-${\beta}$-D-Thiogalactopyranoside), was up to 38.9% of the total cellular protein. The fusion protein was purified by Ni-NTA affinity chromatography and cleaved by a SUMO-specific protease to obtain the native hEGF, which was further purified by Ni-NTA affinity chromatography. The result of the reverse-phase HPLC showed that the purity of the recombinant cleaved hEGF was greater than 98%.

• Elastomers and Composites
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• v.34 no.2
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• pp.147-155
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• 1999

Waxes compounded into rubber migrate to the surface and form a protection film on the rubber surface. In general, antiozonants were used with wax to protect ozonation of rubber. Influence of wax barrier formed on the surface of a rubber vulcanizate on migration of antiozonants was studied using natural rubber (NR) vulcanizates containing various type waxes. IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine), HPPD (N-l,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), SBPPD (N,N'-di(sec-butyl)-p-phenylenediamine), and DMPPD (N,N'-di(1,4-dimethylpentyl)-p-phenylenediamine) were employed as antiozonants. Migration experiments were performed at constant temperatures of 60 and $80^{\circ}C$ for 10, 20, 30 days using a convection oven. The migration rates of the antiozonants in the vulcanizate without wax are faster than those in the vulcanizates containing waxes. The antiozonants migrate slower in the vulcanizate containing wax with a high molecular weight distribution than in the vulcanizate with a low one. The migration rates of DMPPD and SBPPD are faster than those of HPPD and IPPD.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.9-14
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• 2004

In this study, Si anisotropic etching characteristics of tetramethylammonium hydroxide (TMAH)/ ammonium persulfate(AP)/isopropyl alcohol(IPA) solutions were investigated to realize the optimum structure of a diaphragm for the piezoresistive pressure sensor application. Due to its low toxicity and its high compatibility with the CMOS processing, TMAH was used as Si anisotropic etchants. The variations of Si etch rate on the etching temperature, TMAH concentration, and etching time were obtained. With increasing the etching temperature and decreasing TMAH concentrations, the Si etch rate is increased while a significant non-unifonnity exists on the etched surface because of formation of hillocks on the (100) surface. The addition of IPA to TMAH solution leads to smoother etched surfaces but, makes the Si etch rate lower. However, with the addition of AP to TMAH solution, the Si etch rate is increased and an improvement in flatness on the etching front is observed. The Si etch rate is also maximized with increasing the number of addition of AP to TMAH solution per one hour. The Si square membranes of 20${\mu}{\textrm}{m}$ thickness and l00-400${\mu}{\textrm}{m}$ one-side length were fabricated successfully by applying optimum Si etching conditions of TMAH/AP solutions.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.205-213
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• 2009

This study reports on the geometry optimizations and electronic structure calculations for methyl pyropheophorbide (MPPa), tropolonyl methyl pyropheophorbides (TMPPa, ITMPPa), and cationic tropolonyl methyl pyropheophorbides ($TMPPa^+{{\cdot}BF_4}^-,\;ITMPPa^+{{\cdot}BF_4}^-,\;TMPPa^+,\;and\;ITMPPa^+$) using Local Spin Density Approximation (LSDA/ 6-31G*) and the Restricted Hatree-Fock (RHF/6-31G*) level theory. From the calculated results, we found that substituted cationic tropolonyl groups have larger structural effects than those of substituted neutral tropolonyl groups. The order of structural change effects is $ITMPPa^+ > ITMPPa^+{{\cdot}BF_4}^-$ > ITMPPa, as a result of the isopropyl group. Because it is an electron-releasing group, the substituted isopropyl group electronic effect on a 3-position tropolone increases the Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital (HOMO-LUMO) energy gap. It was constituted that the larger the cationic characters of these photosensitizers, the smaller the HOMOLUMO band gaps are. The orbital energies of the cationic systems and the ions are stronger than those of a neutral system because of a strong electrostatic interaction. However, this stabilization of orbital energies are counteracted by the distortion of chlorin macrocycle, which results in a large destabilization of chlorin-based compound HOMOs and smaller destabilization of LUMOs as shown in TMPPa (ITMPPa), $TMPPa^+{{\cdot}BF_4}^- (ITMPPa^+{{\cdot}BF_4}^-),\;and\;TMPPa^+\;(ITMPPa^+)$ of Figure 6 and Table 6-7. These results are in reasonable agreement with normal-coordinate structural decomposition (NSD) results. The HOMO-LUMO gap is an important factor to consider in the development of photodynamic therapy (PDT).

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1440-1446
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• 1999

Fourty-two commercial vinegars were analyzed for their non-volatile organic acids, free sugars. amino acids, and volatile compounds. A study was made to characterize commercial vinegars chemically into three kinds of vinegars such as spirit, cider, and brown rice vinegars. Sixteen chemical components were significantly effective for the chemical characterization of commercial vinegars by stepwise discriminant analysis. Those were malic, succinic and lactic acids from the non-volatile organic acids; fructose and glucose from the free sugars; lysine, serine, leucine, valine and alanine from the amino acids; 1-hexanol, acetaldehyde, 3-methyl-1-butanol, 2-methylpropanoic acid, isopropyl butanoate and ethanol from the volatile compounds. Six components including malic acid, lysine, succinic acid, glucose, lactic acid and 1-hexanol were the most significant contributors to the differentiation of commercial vinegars into spirit, cider, and brown rice vinegars. In particular, cider vinegars could be characterized to be abundant in amounts of malic acid and 1-hexanol, whereas brown rice vinegars in amounts of lysine and lactic acid compared to spirit vinegars.

• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.1-11
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• 1987

The degradation of two chemicals seem to be clearly affected by soil microbial activity in submerged soil $conditions(30{\pm}1^{\circ}C)$. The Active ingredient of Diazinon disappeared about 5 times faster than that of Dursban. By Applying 300% higher concentrations of both chemicals. under the above soil conditions, however, degradation was retarded by about one day. Some of the metabolites of Diazinon were as follows: 0.0-diethyl phosphorothioate and sulfotep as hydrolytic products, and diazoxon, 0.0-diethyl-0-[2-(1-hydroxy-1, 1-dimethyl)-6-methyl]-pyrimidinyl phosphorothioate and 2-isopropyl-6-methyl-pyrimidine-4-one as degradation products of monooxygenase. But 0. 0-diethyl phosphorothioate was the only methabolite of Dursban.

• Resources Recycling
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• v.7 no.4
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• pp.35-42
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• 1998

Surface mount technology is the biggest theme in the area of deιIronic component. To miniatunze an electronic component, s such as ferrite chip inductor, the cer뼈lic wet process for green-sheet lamination and/or screen printing method through a s solvent medium system is widely used. The preparation and characterization of NiCuZn Ferrite (NCZF) shurry and the green s sheet using the water mixed binder system has been studied. The 21 vol% of NCZF slurry was prepared by a ball milling. The p polyacrylic vinyl copolymer (Mw; 60,000) was used as a binder. Th$\xi$ mixture of distilled water, isopropyl alcohol (IPA) and 2l butoxy ethanol was used as a dispersion medium. The water content of medium varied from about 40% to 80%. As the results. Thc disp$\xi$rston stability of the NCZF slurry was attributed to the free polymer rather than the electrostatic force of the particle. T The viscosity of the NCZF slurry was greatly depended on the ratio of water content in the medium.

• Membrane Journal
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• v.25 no.5
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• pp.385-390
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• 2015

To determine the pervaporation separation characteristics of IPA/water mixtures, PEI/PDMS hollow fiber membrane module commercialized by Airrane Co. was subjected to both lab and pilot tests. The flux of $0.52kg/m^2h$ and IPA concentration of 68.5% at $25^{\circ}C$ were obtained whereas the $1.368kg/m^2h$ and 61.2% were measured at $55^{\circ}C$. In order to realized the durability of the module, the long-term test (at $50^{\circ}C$) of 100 days has been conducted and as a result, the flux $1.03{\sim}1.15kg/m^2h$ and IPA concentration 61.8~62.5% were maintained with the initial values.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1317-1323
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• 2005

In an attempt to examine the ability of benzisothiazole-based drugs to interact with $\beta$-adrenoceptors, a series of 1,2-benzisothiazole derivatives, which were substituted with various propanolamine or oxypropanolamine side chains in the 2 or 3 position, were synthesised and tested. The pharmacological activity of these compounds at the ,$\beta$-adrenoceptors was examined using isolated rat atria and small intestinal segments, which preferentially express the $\beta_{1}$- and $\beta_{3}$-adrenoceptor-mediated responses, respectively. None of these products showed any $\beta$-adrenoceptor agonistic activity. In contrast, the 2- and 3-substituted isopropyl, tert-butyl, benzyl, and piperonyl derivatives 2a-d and 3a-d elicited surmountable inhibition of the isoprena­line-induced chronotropic effects in the atria, suggesting competitive antagonism at the $\beta_{1}$­recognition site. The $pA_{2}$ values revealed tert-butyl 3b and the isopropyl substituted piperonyl derivatives 3a to be the most effective. Remarkably, many of the 2-substituted propanolamines were less active than the corresponding 3-substituted oxypropanolamines. With the exception of compound 3b, none of these drugs antagonised the muscle relaxant activity of isoprenaline in the intestine, suggesting no effect on the $\beta_{3}$-adrenoceptors. These results confirm the ability of the benzisothiazole ring to interact with the $\beta$-adrenoceptors, and demonstrate that 2-substitution with propanolamine or 3-substitution with oxypropanolamine groups yields compounds with preferential antagonistic activity at the cardiac $\beta_{1}$adrenoceptors. The degree of antagonism depends strongly on both the nature of the substituent and its position on the benzisothiazole ring.