• The Korean Journal of Pain
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• 제7권2호
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• pp.217-221
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• 1994

Percutaneous neurolysis of upper thoracic sympathetic ganglion was performed in 40 patients by simultaneously injecting 3 ml of pure alcohol into the T2 and T3 levels after 3 ml of injection of local anesthetic agent on the same sites. Using a skin temperature probe, finger tip temperatures were measured on the index finger ipsilateral to the nerve block before block, 15 and 30 minutes after test block, and 30 minutes after alcohol block. Alcohol block was performed immediately after 30 minutes test block. Finger tip temperatures obtained at 30 minutes post alcohol block and test block and the differences in the temperatures measured before and 30 minutes after alcohol block were shown to be statistically important as potential indicators for prediciting long term outcome of therapy for palmar hyperhidrosis using this technique. These results demonstrate that the palmar temperature monitoring method is sufficiently sensitive to predict the outcome of nerve block during and after thoracic sympathetic ganglion block.

• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.225-236
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• 2020

This paper examines empirically the net impact of residual state ownership on privatized firm efficiency in the transitional context of Vietnam. Vietnamese privatization has its own characteristics. Instead of mass and full privatization, Vietnam has chosen a partial and gradual path. Thus, it is important to assess the net impact of residual state ownership on privatized firms during the post-privatization period. This study employs stochastic frontier analysis to investigate the association between residual state ownership and the efficiency of privatized firms, using a sample of all privatized firms that are listed on the Vietnamese stock exchanges over the period from 2007 to 2017. Also, two-stage least squares regression is incorporated into the model to deal with potential endogeneity issues. Our study provides evidence that state ownership should not be considered as a pure source of agency problems. Indeed, the net impact of residual state ownership on privatized firm efficiency is non-monotonic, and the relationship between residual state ownership and privatized firm efficiency is under an inverted U-shape. A moderate level (less than 50%) of residual state ownership might be beneficial to privatized firm efficiency whereas too much state ownership is detrimental to the efficiency of privatized firms.

• Environmental Engineering Research
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• 제17권1호
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• pp.3-8
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• 2012

A scaled-up bioconversion of fishmeal wastewater (FMW) into liquid fertilizer was performed five times in a $1m^3$ reactor in order to examine the feasibility of commercialization. The importance of aeration was marked. Analyses indicated that dissolved oxygen (DO) level was closely related to the value of oxidation-reduction potential (ORP) and it was crucial to achieve high-quality liquid fertilizer. When pure oxygen was supplied through four diffusers into the reactor, DO levels and ORP values were maintained over 1.2 mg/L and 0.2 mV, respectively all the time during 52 hr of bioconversion. The pH changed from 6.8 to 5.9. The average removal percentages of chemical oxygen demand ($COD_{Cr}$) and total nitrogen (TN) were 75.0% and 71.6%, respectively. Compared to the result acquired in a 5-L reactor, bioconversion of FMW into liquid fertilizer was achieved in a shorter time under the same removal percentages of $COD_{Cr}$ and TN. The 52-hr culture of inoculated FMW was phytotoxic-free and it possessed comparable fertilizing ability to a liquid fertilizer made from the fish waste in hydroponic culture with amino acid contents of 5.93 g/ 100 g sample. From all the above results, transferring lab-scale data to large-scale production appeared to be successful. As a result, the commercialization of a liquid fertilizer made from FMW was feasible.

• International Journal of Industrial Entomology and Biomaterials
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• 제21권2호
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• pp.169-174
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• 2010

Hydrolysate silk fibroin (HSF) is a fibrous protein composed of parallel $\beta$-structures and is made from pure silk elements including 18 amino acids, with glycine, alanine, and serine comprising of over 80% of the amino acids. Numerous studies have documented a range of effects of HSF, including moisturizing, antioxidant activity, nervous system disorders, and many more. We investigated whether HSF has anti-obesity effects in vitro. The effects of HSF inhibition on lipid accumulation and acceleration of lipid degradation in 3T3-L1 cells were studied. Treatment of 3T3-L1 cells with HSF caused significant inhibition of cell viability, an increase in glycerol release, and a decreased in adipocyte differentiation. Moreover HSF stimulated downregulated of adipogenic enzyme expressions (PPAR${\gamma}$ and C/EBP${\alpha}$) and up-regulated of fatty oxidation enzyme expressions (CPT-1 and UCP-2). Based on these results, hydrolysate silk fibroin can be suggested as a potential therapeutic substance as part of a prevention or treatment strategy for obesity.

• 한국재료학회지
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• 제25권4호
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• pp.171-176
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• 2015

We present the detection characteristics of nitrogen monoxide(NO) gas using p-type copper oxide(CuO) thin film gas sensors. The CuO thin films were fabricated on glass substrates by a sol-gel spin coating method using copper acetate hydrate and diethanolamine as precursors. Structural characterizations revealed that we prepared the pure CuO thin films having a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the NO gas sensing measurements that the p-type CuO thin film gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as $100^{\circ}C$. Additionally, these CuO thin film gas sensors were found to show reversible and reliable electrical response to NO gas in a range of operating temperatures from $60^{\circ}C$ to $200^{\circ}C$. It is supposed from these results that the p-type oxide semiconductor CuO thin film could have significant potential for use in future gas sensors and other oxide electronics applications using oxide p-n heterojunction structures.

• 한국표면공학회지
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• 제42권3호
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• 한국주조공학회지
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• 제33권6호
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• pp.242-247
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• 2013

The most widely utilized commercial, aluminum-casting alloys are based on an aluminum-silicon system due to its excellent casting, and good mechanical, properties. Unfortunately, these Al-Si based alloys are inherently poor energy conductors; compared to pure aluminum, because of their high silicon content. This means that they are not suitable for applications demanding high eletrical or thermal conductivity. Therefore, efforts are currently being made to develop new, highly-conductive aluminum-casting alloys containing no silicon. In this research, a number of properties; including potential for castability, were investigated for a number of Al-Fe-Zn-Cu alloys with varying Cu content. As the copper content was increased, the tensile strength of Al-Fe-Zn-Cu alloy tended to increase gradually, while the electrical conductivity was slightly reduced. Fluidity was found to be lower in high-Cu alloys, and susceptibility to hot-cracking was generally high in all the alloys investigated.

• 한국수소및신에너지학회논문집
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• 제19권4호
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• pp.291-298
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• 2008

Carbon monoxide(CO) is one of the contamination source in reformed hydrogen fuel with an influence on performance of polymer electrolyte membrane fuel cell(PEMFC). The studies of CO injection presented here give information about poisoning and recovery processes. The aim of this research is to investigate cell performance decline due to carbon monoxide impurity in hydrogen. Performance of PEM fuel cell was investigated using current vs. potential experiment, long time(10 hours) test, cyclic feeding test and electrochemical impedance spectra. The concentrations of carbon monoxide were changed up to 10 ppm. Performance degradation due to carbon monoxide contamination in anode fuel was observed at high concentration of carbon monoxide. The CO gas showed influence on the charge transfer reaction. The performance recovery was confirmed in long time test when pure hydrogen was provided for 1 hour after carbon monoxide had been supplied. The result of this study could be used as a basis of various reformation process design and fuel quality determination.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2613-2619
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• 2020

This work investigated the gamma-ray shielding performance, and the physical and mechanical properties of poly (methyl methacrylate) (PMMA) composites embedded with 0-44.0 wt% bismuth trioxide (Bi₂O₃) fabricated by the fast ultraviolet (UV) curing method. The results showed that the addition of Bi₂O₃ had significantly improved the gamma shielding ability of PMMA composites. Mass attenuation coefficient and half-value layer were examined using five gamma sources (Cs-137, Ba-133, Cd-109, Co-57, and Co-60). The high loading of Bi₂O₃ in the PMMA samples improved the micro-hardness to nearly seven times that of the pure PMMA. With these enhancements, it was demonstrated that PMMA/Bi₂O₃ composites are promising gamma shielding materials. Furthermore, the fast UV curing exerts its great potential in significantly shortening the production cycle of shielding material to enable rapid manufacturing.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.383-391
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• 2014

Biotin-S-S-Phosphine was designed and synthesized as a potential tool for a proteomic study of O-GlcNAcmodified proteins. This reagent features a disulfide linker between a triarylphosphine moiety, which allows selective conjugation to azide-containing proteins, and a biotin moiety that can allow easy isolation through its strong affinity toward avidin-coated solid beads. The disulfide linkage within this reagent can allow the easy release of the bound molecules of interest, which is difficult to achieve when a biotin:avidin pair is used alone, by reducing the disulfide bond of the reagent with DTT. Preliminary in vitro biological assays with azidelabeled and unlabeled cell lysates and a pure protein Nup62 showed that the Biotin-S-S-Phosphine reagent is highly reactive toward the free thiol groups of proteins. When a molecular tool with a disulfide linker is applied to the enrichment of the molecules of interest from other species, it is important to block the free-thiols of the sample using exhaustive alkylation prior to the Staudinger ligation reactions to restore the bioorthogonal nature of this reaction.