• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.227-228
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• 2012

In interfaces between carbon black or Pt and FTO glass in dye-sensitized solar cell counter electrodes, a marginal resistant channel for electrons, we tried to improve the connection by modifying the sintering process. A stepwise sintering process for carbon black and Pt counter electrodes was applied and its effect on power conversion efficiency was studied. Power conversion efficiencies of built-in DSSC made by a one-step sintering process with carbon black and Pt counter electrodes were about 5.01% and 5.02%, respectively. Cells made with the stepwise sintering process were 5.96% and 6.21%, respectively, indicating an 20% improvement. Fill factor (FF) increased, and it was them main reason for the power conversion efficiency improvement. Step wise sintering increased the adhesion of the interface and reduced the film thickness and surface roughness. As a result, the resistivity of the counter electrode and EIS impedance of DSSCs decreased.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.636-639
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• 2003

Entercbacter agglomerans 6L was isolated from citron (Citrus junos) peel by using an enrichment culture containing (+)-limonene. It was able to metabolize limonene and grew well ($A_{600}$:4.5) on limonene as a sole carbon source. E. agglomernas 6L was highly resistant to limonene toxicity, and grew to 1.0 optical density ($A_{600}$) even at 5% (v/v) of limonene in Luria-Bertani media. ${\gamma}-Valerolactone$ and cryptone were detected as the major metabolic products of limonene by E. agglomerans 6L.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1143-1153
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• 1998

Background : Recent outbreaks of pulmonary disease due to drug-resistant strains of Mycobacterium Tuberculosis have resulted in significant morbidity and mortality in patients worldwide. We reviewed our experience to evaluate the effects of pulmonary resection on the management of multidrug-resistant tuberculosis. Method : A retrospective review was performed of 41 patients undergoing pulmonary resection for multidrug-resistant tuberculosis between January 1993 and December 1997. We divided these into 3 groups according to the radiologic findings : (1) patients who have reasonably localized lesion (Localized Lesion Group ; LLG) (2) patients who have cavitary lesions after pulmonary resection on chest roentgenogram (Remained Cavity Group : RCG) (3) patients who have Remained infiltrative lesions postoperatively (Remained infiltrative group : RIG). We evaluated the negative conversion rate after resection and overall response rate of the groups. Then they were compared with the results of the chemotherapy on the multi drug-resistant tuberculosis which has been outcome by Goble et al. Goble et al reported that negative conversion rate was 65% and overall response rate, 56% over a mean period of 5.1 months. Results : Seventy five point six percent were men and 24.4% women with a median age of 31 years (range, 16 to 60 years). Although the patients were treated preoperatively with multidrug regimens in an effort to reduce the mycobacterial burden, 22 of 41 were still sputum culture positive at the time of surgery. 20 of 22 patients(90.9%, p<0.01) responded which is defined as negative sputum cultures within 2 months postoperative. Of 26 patients with the sufficient follow up data, 19 have Remained sputum culture negative for a mean duration of 25.7 months (73.1%, p<0.05). The bulk of the disease was manifest in one lung, but lesser amounts of contralateral disease were demonstrated in 15, consisted of 8 in RIG and 7 in RCG, of 41. 12 of 12 patients (100%, p<0.01) who were sputum positive at the time of surgery in LLG converted successfully. 14 of 15 patients (93.3%, p<0.05) with the follow up have completed treatment and not relapsed for a mean period of 25. 7 months. The mean length of postoperative drug therapy of LLG was 12.2 months. In RIG, postoperative negative conversion rate was 83.3% which was not significant statistically. There was a statistical significance in overall response rate (100%, p<0.05) of RIG for a mean period of 24.4 months with a mean length of postoperative chemotherapy, 11.8 months. In RCG a statistically lower overall response rate (14.3%, p<0.01) has been revealed for a mean duration of follow up, 24.2 months. A negative conversion rate of RCG was 75% which was not significant statistically. Conclusion : Surgery plays an important role in the management of patients with multidrug-resistant Mycobacterium tuberculosis infection. Aggressive pulmonary resection should be performed for resistant Mycobacterium tuberculosis infection to avoid treatment failure or relapse. Especially all cavitary lesions on preoperative chest roentgenogram should be resected completely. If all of them could not be resected perfectly, you should not open the thorax.

• Journal of the Korean Professional Engineers Association
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• v.33 no.6
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• pp.16-23
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• 2000

Anodizing processes is the conversion of the aluminum surface to aluminum oxide while the part is the anode in an electrolytic cell. The object of the anodizing was increased corrosion resistant, paint adhesion and was provided unique, decorative colors. Many electrolytes, under different conditions, have been used for the anodic oxidation of alumminum and its alloys. This paper deals with the procedures used in the anodic oxidation of aluminum and its alloys, the nature and properties of the oxide films, their uses and anodizing equipment and process control.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.129-134
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• 2005

Effective micropropagation system via somatic embryognesis was established for a Phytophthora resistant Aralia elata cultivar. Different kinds of growth regulators were needed to induce embryogenic callus with different explant sources. When leaf explants were used, a combination of 2,4-D, TDZ and L-glutamine was needed, whereas when petiole and root explants needed only 1.0 mg/L 2,4-D. Embryogenic callus induction rate under the optimum culture condition was 75.0%, 67.0% and 83.0% from leaf, petiole and root segment, respectively. Somatic embryo germination and plantlet conversion rate appeared to be influenced greatly by various osmoticums. More than 90% of embryos germinated when treated with sucrose, glucose and maltose. However, the highest conversion rate (72%) was recorded on medium with 2% sucrose only. The converted plantlets grew normally on 1/2MS basal medium, were acclimatized on artificial soil mixture and survived more than 95% in the greenhouse condition. The results suggest that the species can be clonally propagated through in vitro culture system via somatic embryogenesis.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.49-55
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• 2000

Lysogenic conversion of Staphylococcus aureus to loss of ${\beta}-hemolysin$ production by serological group F phages is always associated with gain in staphylokinase production. In this study, the new phages belonging to serotype F were detected during the course of isolation of phages from Staph aureus of bovine origin and some characteristics of the new phages isolated were investigated. The new phages, ${\phi}470$ and ${\phi}499$, isolated from Staph aureus producing ${\beta}-hemolysin$ and staphylokinase(${\beta}^+\;K^+$) were found to convert ${\beta}^+\;K^+$ strain to ${\beta}^+K\;^+$, Staph aureus strains lysogenized by this serotype F single-converting phage ${\phi}470$ or ${\phi}499$ could be again lysogenized with serotype F double-converting phage ${\phi}506$. The frequency of lysogenization of indicator strains by serotype F single-converting phage was 100%, whereas the frequency for serotype F double-converting phage ${\phi}506$ varied from 4.2% to 97.6% according to the indicator strains. The indicator strain lysogenized with phage ${\phi}470$ was resistant to phage ${\phi}499$, and vice versa, but not to phage ${\phi}506$. Therefore, phage ${\phi}470$ and ${\phi}499$ were shown to be identical by immunity test.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1023-1032
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• 2017

When a cryptographic device such as smart card performs an encryption for a plain text, an attacker can extract the secret key in it using side channel information. Especially, many researches found some weaknesses for side channel attack on the lightweight block cipher LEA designed to apply in IoT environments. In this paper, we survey several masking countermeasures to defeat the side channel attack and propose a novel masking conversion method. Even though the proposed Arithmetic-to-Boolean masking conversion method requires storage memory of 256 bytes, it can improve the LEA encryption speed up to 17 percentage compared to the case adopted the previous masking method.

• Journal of Life Science
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• v.27 no.2
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• pp.172-179
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• 2017

The fermentation of Panax ginseng can yield many compounds from ginsenosides that have a wide variety of biological functions. Lactic acid bacteria (LAB) strains are capable of converting ginsenosides. The purposes of this study were to: (1) characterize Enterococcus faecium SA5, an isolated LAB from Mongolian mare milk, (2) identify the existence of extracellular ${\beta}$-glucosidase activity in the milk, and (3) ascertain if the ${\beta}$-glucosidase has the capacity of converting ginsenoside in Korean ginseng. The results revealed that E. faecium SA5 was acid-resistant, bile salt-resistant, and has antibiotic activities against 4 pathogenic microorganisms (Salmonella typhimurium KCTC 3216, Listeria monocytogenes KCTC 3710, Bacillus cereus KCTC 1012, Staphylococcus aureus KCTC 1621). In addition, E. faecium SA5 had tolerance against some antibiotics such as colistin, gentamycin and neomycin. It was also found that E. faecium SA5 possessed bile salt hydrolase activity, which could lower blood cholesterol level. When incubated in 10% (w/v) skim milk as a yogurt starter, E. faecium SA5 caused to decrease pH of the medium as well as increase in viable cell counts. Using TLC and HPLC analysis on the samples incubated in MRS broth, our study confirmed that E. faecium SA5 can produce ${\beta}$-glucosidase, which was capable of converting ginsenoside $Rb_1$ into new ginsenosides $Rg_3-s$ and $Rg_3-r$. It was concluded that E. faecium SA5 possessed a potential of probiotic activity, which could be applied to yogurt manufacture as well as ginsenoside conversion in ginseng.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.862-870
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• 1996

Background : Multidrug-resistant tuberculosis(MDR-Tb) has been increased not only in Asia but also in Western society, which may cause public health problems and reduce the efficacy of treatment of tuberculosis. In Western society HIV infection is believed to do a central role in increasing incidence of MDR tuberculosis, but MDR-Tb in Korea may be somewhat different about clinical features, underlying disorders, and prognosis. Goble et al reponed that overall treatment failure rate in MDR-Tb including resistance to isoniazid(INH) and rifampin (RFP) was 44 %. The aim of this study is to find the treatment result in Korea and the factors determining the prognosis. Methods: A retrospective study of pulmonary tuberculosis cultured M. tuberculosis from sputum or bronchial washing fluid between 1986 through 1992 was conducted in the Seoul Paik Hospital, Inje University. We reviewed clinical courses of 141 patients, who had a tuberculosis with resistance to 2 or more drugs including isoniazid(INH) and rifampin(RFP). One hundred and 4 patients of 141 patients had completed treatment and followed up for more than one year. Results: Of 104 (mean age $43.6{\pm}16.7$, M: F=63 : 41) patients with sufficient follow-up data, 73(84.6%) patients responded which is defined as negative Sputum cultures for at least 3 consecutive months. Seven patients(6.7%) had a failure in negative conversion and 9(8.7%) of the patients who initially responded relapsed. Overall treatment failure rate was 15.4%, Patients who were treated for less than 12 months had a higher relapse rate(12.3%) than 18 months(4.9%). And there was a statistically significant correlation between the relapse rate and the number of drugs to which isolates wera resistant(p<0.05). Conclusion : The treatment failure rate of MDR-Tb in Korea was lower than previous studies in western Country and the major determining factor of prognosis was the number of resistant drugs to M. tuberculosis at drug sensitivity test. For reducing the relapse rate, we recommend more than 12 months of treatment for MDR tuberculosis.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.192-200
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• 2018

In this study, improvements for error correction, speed, position, and rotation calculation algorithms have been proposed to be used in resolver to digital conversion (RDC) systems. The proposed open-loop system drives the resolver and uses the output signals of the resolver signal to estimate the real time position, the instant speed, and the rotation count with high resolution and accuracy even at high speeds and noise. The proposed solution implements strong features of both closed and open loop based systems while eliminating their weak points. The improvements proposed is resistant to noise owing to digital FIR filter and data averaging techniques. The implementation used for proof of concept is implemented on a hardware using an FPGA and configurable to be used by any resolver.