• 한국재료학회지
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• 제16권6호
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• pp.386-393
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• 2006

Increasing environmental concerns require to solve the problem produced due to the use of heavy metals in coating formulations. Therefore, it is necessary to develop new coating strategy employing inherently conducting polymers such as polyaniline. Polyaniline is a conductive polymer that is synthesized by oxidation polymerization, and the electrochemical and chemical polymerization are possible for the oxidation of aniline. Electrochemical oxidation polymerization produces a fine surface and although voltage control is more convenient, it require electrolytic cells, and elaborate thin film can be acquired with the polymerization. Polyaniline films were electro-polymerized on cold rolled sheets using the galvanostat mode in the oxalic acidaniline-sodium molybdate electrolyte. The structure and properties of polyaniline film were studied using Potentiostat/Galvanostat 263A, FE-SEM,, AFM, SST, Colorimetry. A high corrosion resistance of polyaniline film was observed with an increase of corrosion potential by $500{\sim}600$ mV for the substrate covered with polyaniline.

• 한국임상수의학회지
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• 제19권1호
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• pp.19-22
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• 2002

The examination with 96 bacteria isolates for antibiotics susceptibility was resulted in exploring many antibiotics resistance isolates from the diseased fishes. Vibrio sp. isolates were demonstrated over 90% resistances for Penicillin (P), Amoxicillin (Amc), Erythromycin (I), Colistin (CL). Streptomycin (S). Novobiocin (NV) and Neomycin(N), these isolates were, however, appeared over 80% susceptibilities for Norfloxacin (Nor), CE and UB. In Edwardsiella tarda case, 90 to 100% high resistance was observed for P, Doxycycline (Do), Tetracyclin (Te), Oxytetracycline (T), E, CL, Sulfamethoxasoletrimetoprim (SXT), S, Oxolinic acid (OA), W, Neomycin(N), on the contrary, 90 to 100% high susceptibilities was found for Amc, Nor, Ciprofloxacin (Cip), Orbifloxacin (ORB), Enrofloxacin (ENR), Flumeguine (UB) and NA. CL, Pefloxacin (PEF),S, Flumeguine (UB), OA, NA, NV N was exhibited 90 to 100% resistances for Streptococcus sp., on the other hand, 100% susceptible to AMC and 80% susceptible to Do, Te, ENR and UB was recognised. Lastly, Photobacterium damsela subsp. piscicida was showed 100fe susceptible to Amc and 86% susceptible to NOR, CIP ENR and UB. As a consequence, fish bacterial pathogens isolated from Kyeongnam area, especially Tongyeong-si, Geoje-si, and Goseong-gun, were showed highly resistant to a variety of antibiotics available in the field.

• 한국축산식품학회지
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• 제30권2호
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• pp.223-231
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• 2010

In order to develop a new starter for fermented milk, Lactobacillus paracasei subsp. paracasei BFI46 (BFI46) obtained from new-born infant feces was investigated for physiological characteristics. Good immunomodulating activity was evident compared with commercial lactic acid bacteria starter cultures. The optimum growth temperature of BFI46 was $40^{\circ}C$ with 12 h required to reach pH 4.3. Testing with 13 different antibiotics revealed greatest sensitivity of BFI46 to penicillin- G and chloramphenicol, and heightened resistance to neomycin, kanamycin and polymyxin. BFI46 displayed higher esterase activities compared to 18 other enzymes, was comparatively tolerant to bile juice and able to survive at pH 2 for 3 h, and displayed high resistance against Escherichia coli and Salmonella Typhimurium with a survival rate of 57.14% and 96.36%, respectively. The results indicate that BFI46 could be an excellent starter culture for fermented milk with high level of immunomodulating activity.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.325-336
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• 2010

In this study, we experimented that how to synthesis waterborne urethane-epoxy hybrid resin for leather garment coatings. First of all, We had analyzed datas by FT-IR, SEM and TGA for the machanical properties. By instruments analysis measurement we confirmed that synthesis of urethane and epoxy. In this experiment we knew that polyurethane and urethane-epoxy hybrid resin have 4~5 grades of solvent resistance. Tensile strength measured in the urethane-epoxy resin(epoxy 12%, 2.033$kg_f/mm^2$) had the most strong strength than polyurethane(1.833 $kg_f/mm^2$) emulsion samples. Also urethane-epoxy hybrid resin had better result than polyurethane in acid resistance and abrasion test. As hight proportion of epoxy in hybid resin, we obtained low elongation and low flexibility. In this result, the mechanical properties of waterborne polyurethane-epoxy hybrid resin showed that how effect in leather coating by ratio of epoxy emulsion.

• 접착 및 계면
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• 제8권4호
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• pp.8-13
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• 2007

본 연구에서는 teramethylxylene diisocyanate (TMXDI)와 poly(tetramethylene glycol) (PTMG), polycarprolactone (PCL), dimrthylol proponic acid (DMPA)를 사용하여 무용제형 수분산 폴리우레탄을 합성하였으며, 음이온성기의 함량이 열적, 기계적 물성 및 접착력에 미치는 영향을 검토하였다. 합성된 무용제형 수분산 폴리우레탄의 Tg는 $-70{\sim}-50^{\circ}C$ 범위이고 PCL의 함량이 증가함에 따라 Tg는 상승하였다. 인장강도와 접착력, 열 안정성은 PCL과 음이온성기의 함량이 증가함에 따라 증가하였고 신율은 감소하였다.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.790-796
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• 2004

Ginseng is a shade-loving perennial herb that is cultivated mainly in Korea, Japan, and China. The ginseng root has been used as a tonic remedy, and its antidiabetic activity has been demonstrated as early as 1920s. Although wild ginseng was anecdotally thought to be superior to cultivated ginseng as far as pharmacological properties were concerned, there have been no prior reports on the antidiabetic effect of wild ginseng. In this study, we investigated the preventative anti-diabetic and anti-obese effects of wild ginseng ethanol extract (WGEE). In the preventive experiment, WGEE co-administered with a high fat diet significantly inhibited body weight gain, fasting blood glucose, triglyceride, and free fatty acid levels in a dose dependent manner. WGEE-treated mice at doses of 250 and 500 mg/kg improved the insulin resistance index by 55％ and 61％ compared to the high fat diet (HFD) control, respectively. Diameters of white and brown adipocytes were also decreased by 62％ and 46％ in the WG500-treated group compared to those in HFD fed control mice. Taken together, WGEE has potential as a preventive agent for type 2 diabetes mellitus (and possibly obesity) and deserves clinical trial in the near future.

• Membrane and Water Treatment
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• 제8권2호
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• pp.185-199
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• 2017

Low-pressure membrane filtration is increasingly used for tertiary treatment of wastewater effluent organic matter (EfOM), mainly comprising organic base/neutral compounds. In-line coagulation with underdosing, charge neutralization, and sweep floc conditions prior to ultrafiltration (UF) was studied to determine removals of the EfOM components and consequent reduction of fouling using polyethersulfone membranes. Coagulation and UF substantially reduced fouling for all coagulation conditions while removing from 7 to 38% of EfOM organic acids. From 7 to 16% of EfOM organic base/neutrals were removed at neutral pH but there was no significant removal for slightly acid coagulation conditions even though fouling was substantially reduced. Sweep floc produced the lowest resistance to filtration but may be inappropriate for in-line use due to the large added volume of solids. Charge-neutralization resulted in poor recovery of the initial flux with hydraulic cleaning. Under-dosing paralleled sweep floc in reducing hydraulic resistance to filtration (for sub-critical flux) and the initial flux was also easily recovered with hydraulic cleaning. Hydrophobic and hydrophilic base/neutrals were identified on the fouled membranes but as previously reported the extent of fouling was not correlated with accumulation of organic base/neutrals.

• 대한소화기학회지
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• 제72권5호
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• pp.237-244
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• 2018

While the prevalence of Helicobacter pylori (H. pylori) infection is decreasing in Korea, the incidence of gastric cancer remains high, emphasizing the importance of H. pylori eradication. A new treatment strategy is needed as the eradication rate with standard triple therapy, which is currently the standard first-line regimen for H. pylori infection, has decreased below the optimum level. The major cause of eradication failure is increased antibiotic resistance. Sequential, concurrent, and hybrid therapies that include clarithromycin produce higher eradication rates than conventional standard triple therapy. However, the effectiveness of these treatments is limited in regions where the resistance rate to various antibiotics is high. Bismuth quadruple therapy is another alternative therapy, but again the eradication rate is not sufficiently high. Tailored therapy based on individual characteristics, including antibiotic susceptibility, may be ideal, but there are several limitations for clinical application and further research is needed. New potassium-competitive acid blocker-based therapies could emerge as effective alternatives in the near future. A consensus is needed to establish a strategy for applying new eradication therapies in Korea.

• Elastomers and Composites
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• 제54권3호
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• pp.225-231
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• 2019

Bio-based polyester polyol was synthesized via esterification between azelaic acid and isosorbide. After esterification, bio-based polyurethanes were synthesized using polyester polyol, 1,3-propanediol as the chain extender, and 4,4'-diphenylmethane diisocyanate, in mixing ratios of 1:1:1.5, 1:1:1.8, 1:1:2, and 1:1:2.3. The bio TPU (Thermoplastic Polyurethane) samples were characterized by using FT-IR (Fourier Transform Infrared Spectroscopy), TGA (Thermal Gravimetric Analysis), DSC (Differential Scanning Calorimetry), and GPC (Gel Permeation Chromatography). The mechanical properties (tensile stress and hardness) were obtained by using UTM, a Shore A tester, and a Taber abrasion tester. The viscoelastic properties were tested by an Rubber Processing Analyzer in dynamic strain sweep and dynamic frequency test modes. The chemical resistance was tested with methanol by using the swelling test method. Based on these results, the bio TPU synthesized with the ratio of 1:1:2.3, referred to as TPU 4, showed the highest thermal decomposition temperature, the largest molecular weight, and most compact matrix structure due to the highest ratio of the hard segment in the molecular structure. It also presented the highest tensile strength, the largest elongation, and the best viscoelastic properties among the different bio TPUs synthesized herein.

• BMB Reports
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• 제52권5호
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• pp.330-335
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• 2019

Hepatitis B virus (HBV) encoding the HBV x protein (HBx) is a known causative agent of hepatocellular carcinoma (HCC). Its pathogenic activities in HCC include interference with several signaling pathways associated with cell proliferation and apoptosis. Mutant C-terminal-truncated HBx isoforms are frequently found in human HCC and have been shown to enhance proliferation and invasiveness leading to HCC malignancy. We investigated the molecular mechanism of the reduced doxorubicin cytotoxicity by C-terminal truncated HBx. Cells transfected with C-terminal truncated HBx exhibited reduced cytotoxicity to doxorubicin compared to those transfected with full-length HBx. The doxorubicin resistance of cells expressing C-terminal truncated HBx correlated with upregulation of the ATP binding cassette subfamily B member 1(ABCB1) transporter, resulting in the enhanced efflux of doxorubicin. Inhibiting the activity of ABCB1 and silencing ABCB1 expression by small interfering ribonucleic acid (siRNA) increased the cytotoxicity of doxorubicin. These results indicate that elevated ABCB1 expression induced by C-terminal truncation of HBx was responsible for doxorubicin resistance in HCC. Hence, co-treatment with an ABCB1 inhibitor and an anticancer agent may be effective for the treatment of patients with liver cancer containing the C-terminal truncated HBx.