• Tribology and Lubricants
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• v.22 no.1
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• pp.40-46
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• 2006

This paper presents the influence coefficient method to predict the deflection of bump foil precisely in the sub-structure of AFB(air foil bearing). Heshmat has introduced the simple compliance model to calculate the deflection of bump foil. But this approach can not consider the deflection of bump foil at the edge of AFB, so elasto-hydrodynamic model is insufficient to analyze in case that the eccentricity ratio is greater than 1. Peng has used the average pressure and film thickness, but this approach is not also a realistic model. Influence coefficients of a bump is calculated by finite element method, and introduced in bump deflection equations of the performance analysis of air foil bearing. The effects of the influence coefficient on the bearing performance is discussed in detail for appropriate foil design.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1629-1637
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• 2007

An immunochromatography (ICG) strip test using a nanocolloidal gold-antibody probe was developed and optimized for the rapid detection of aflatoxin B1 (AFB1). A monoclonal antibody specific to AFB1 was produced from the cloned hybridoma cell (AF78), coupled with nanocolloidal gold, and distributed on the conjugate pad of the ICG strip test. The visual detection limit of the ICG strip test was 0.5 ng/ml, and this method showed a cross-reaction to aflatoxin B2, G1, and G2. In total, 172 grain and feed samples were collected and analyzed by both the ICG strip test and HPLC. The results of the ICG strip test showed a good agreement with those obtained by HPLC. These results indicated that the ICG strip test has a potential use as a rapid and cost-effective screening tool for the determination of AFB1 in real samples and could be applied to the preliminary screening of mycotoxin in food and agricultural products, generating results within 15 min without complicated steps.

• Korean Journal of Agricultural Science
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• v.47 no.1
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• pp.131-138
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• 2020

The aim of this study was to evaluate the effect of aflatoxin B₁ (AFB₁) on in vitro rumen fermentation at various dose levels of 0 (T₁), 100 (T₂), 200 (T₃), and 300 (T₄) ppb in a wheat straw-based buffalo diet. The results show that the truly degradable dry matter, truly degradable organic matter, gas production, microbial biomass production and partitioning factor values in the control group (T₁) were higher (p < 0.05) than those of the T₂, T₃, and T₄ groups. The total volatile fatty acids, acetate, propionate, and butyrate values in the control group (T₁) were higher (p < 0.05) than those of the T₂, T₃, and T₄ groups. The partitioning factor value in the control group (T₁) was higher (p < 0.05) than those of the T₂, T₃, and T₄ groups. The partitioning factor values of the T₂ and T₃ groups were higher (p < 0.05) than that of the T₄ group. There was no significant variation in the partitioning factor value between the T₂ and T₃ group. The acetate : propionate (A : P) ratio in the control group (T₁) was lower (p < 0.05) than those of the T₂, T₃, and T₄ groups. The A : P ratio in the T₂ group was lower (p < 0.05) than those of the T₃ and T₄ groups. It was concluded that different levels of AFB₁ contamination in feed significantly affect the in vitro rumen fermentation characteristics. Thus, these findings could help to determine the influences of AFB₁ in a wheat straw-based buffalo diet. Additionally, it is necessary to manage AFB₁ contamination in ruminants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.143-148
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• 2003

Antitumorigenic and antimutagenic activities of the doenjangs prepared from mushroom mycelia-cultured traditional mejus (designated to MTDJ) were investigated using the model of Sarcoma-180-induced mouse ascites cancer, and 2-amino-3-methylimidazo ［4,5-f］ quinoline (IQ) and aflatoxin B$_1$ (AFB$_1$) -mediated S. typhimurium mutagenicity, respectively. Antioxidative activity of MTDJ was also investigated using the mouse liver microsome system. Mushroom stains used for the preparation of the mushroom mycelia-cultured traditional mejus were Synryeong (Agaricus blazei), Yeonggi (Canoderma Iucidum), Sanghwang (Phellinus linteus), and Neutari (Pleurotus ostreatus). All MTDJS showed the enhanced antitumorigenicities (12% by Synryeong, 13% by Sanghwang, 16% by Yeonggi, and 19% by Neutari), antimutagenicity (6.1~20.8% for IQ and 3.1~10.2% for AFB$_1$), and antioxidative activity (6.6~46.5%), relative to the control doenjang. The $\beta$-D-glucan content (0.75~1.71 mg/g) of MTDJs was 3~8 times higher than that (0.22 mg/g) of the control doenjang. Genistein content (769~932 Ug/g) of MTDJS was also higher than that (728 Ug/g) of control doenjang The content of $\beta$-D-glucan and genistein was not exactly correlated to the antitumorigenicity and antimutagenicity of MTDJs. These results indicate that anti-tumorigenicity and antimutagenicity of MTDJS were elevated in comparison with the control doenjang, and the observed functions were, in part, derived from $\beta$-glucan and/or genistein in the MTDJS.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.720-729
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• 2000

Background : Histological analysis of tuberculosis shows a spectrum of findings, from well formed granulomatous inflammation with few bacilli in patient with normal immune response to M. tuberculosis to poorly formed granulomatous inflammation with many bacilli in patient with defective immune response. To evaluate the degree of immune response to M. tuberculosis, we studied the histologic features, including the presence of acid fast bacilli(AFB) in lymph node of patients with cervical tuberculous lymphadenitis, and compared them with clinical characteristics. Methods : We reviewed the histologic features of 33 cases of cervical tuberculous lymphadenitis and processed the excised nodes for auramine-rhodamine staining to detect AFB. The AFB positivity in tissue was compared with the histologic features(degree of granuloma formation, presence of caseation necrosis, presence of neutrophilic infiltration) and clinical characteristics(lymph node size, duration of symptom, presence of local symptom or radiologic evidence of pulmonary tuberculosis). Results : 1) The mean age at diagnosis was 42.4 years, and male to female ratio was 1:4.5. 2) Histologically, all cases showed well formed granuloma and variable degrees of caseation necrosis, and 39% of the cases showed neutrophilic infiltration in the granulomatous inflammation. 3) AFB were confirmed in 52% of the cases, and they were found extracellularly and at the periphery of caseation necrosis. 4) There was no association between AFB positivity and histological features or clinical characteristics. Conclusion : Cervical tuberculous lymphadenitis showed well formed granulomatous inflammation with caseation necrosis, and there was no association between AFB positivity in the tissue and histological or clinical characteristics.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.623-630
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• 2008

A non-instrumental immunochromatographic (ICG) strip-test and direct competitive enzyme-linked immunosorbent assay (DC-ELISA) for aflatoxin B1 (AFB1) determination were developed and optimized. The detection limits of ICG strip-test and DC-ELISA were 0.5 and 0.004 ng/mL, respectively, and these methods possessed a cross-reaction to aflatoxins. The results of spiked samples by both methods were coincided with the amount spiked AFB1 and the comparative analyses of 172 real samples by 2 immunoassays and high performance liquid chromatography (HPLC) showed a good agreement. Especially, the ICG strip-test is easier to perform and quicker, but less sensitivity than DC-ELISA. Both methods could analyze a high sample throughput with short time, but the sample throughput of ICG strip-test was better. Therefore, the ICG strip-test can be used as a simple, easy, non-instrumental, and fast screening technique for AFB1 determination.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.900-905
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• 2001

In this study, the levels of insoluble dietary fiber(IDF) and soluble dietary fiber (SDF) in Perilla frutescens seed were quantified and antimutageinc effects of perilla seeds extracts (method extract, hexane extract, methanol soluble fraction and dietary fiber)was carried out IDF and SDF values of perilla seeds were 16.1% and 1.1% , respectively, with 17.2 of total fiber content. Among the solvent extracts of perilla seeds, methanol extract and methanol soluble fraction (MSF) effectively inhibited the mutagenicity induced by aflatoxin B$_{1}$(AFB$_{1}$)in Salmonella typhimurium TA100, Methanol extract of perilla seeds showed 91% inhibition against AFB$_{1}$ mutagen under the 2.5 mg/assay concentration, and MSF inhibited the mutagenicity of 87% by adding 1.25,g/assay. However, perilla seed extracts showed low inhibition rate on the mutagenicity induced by N-methyl-N-nitro-N-nitosoguanidine(MNNG). And also, SDF and hexane extracts from perilla seeds did not show the antimutagenic effects against AFB$_{1}$ and MNNG. On the hand, IDF extracted from perilla seeds inhibited 21% of mutagenicity induced Trp-P-2 due to the carcinogen binding effect.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.22-32
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• 2003

Background : Sputum smears for acid-fast bacilli(AFB) examined microscopically is the most important diagnostic test for pulmonary tuberculosis. However, the AFB observed on the smear may represent either M. tuberculosis or nontuberculous mycobacteria (NTM). This study examined the recovery rate of NTM from the AFB smear-positive sputum specimens in a tertiary hospital in Korea. Materials and Methods : This study analyzed the results for the 1,889 AFB smear-positive and culture-positive sputum specimens collected from 844 patients from July, 1997 to December, 2001. Results : The 1,889 sputum specimens collected from 844 patients tested positive on both microscopy and culture during the 4.5 years. The NTM were recovered from 10.3% (195/1,889) of the smear-positive sputum specimens and 11.0% (93/844) of patients with smear-positive sputum. The NTM were isolated more than two times in 44.1% (41/93) of the patients from whom the NTM was recovered. Trends of the recovery rate of the NTM from the AFB smear-positive sputum specimens were increasing from 6.5%(17/262) in the latter half of 1997 to 17.8%(36/202) in the latter half of 2001 (p<0.001, test for trend). Conclusions : These results suggest that some patients with AFB smear-positive sputum have NTM pulmonary disease rather than pulmonary tuberculosis in Korea.

• Journal of Life Science
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• v.11 no.5
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• pp.432-438
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• 2001

Various lactic acid bacteria were isolated from Korean Dongchimi (whole radish Kimichi with added water) in order to study their antimutagenic activity. Ames test using Salmonella enterica serovar typhimurium TA98 and TA100 showed the strain DLAB19 to have the highest antimutagenic activity among the 300 isolated strains against MNNG(N-methyl-N-nitro-N-nitrosoguanidine), NPD (4-nitro-O-phenylenediamine), 4-NQO(4-nitroquinoline-1-oxide) and AFB$_{1}$(aflatoxin B$_{1}$). The strain was identified as Leuconostoc mesenteroides subsp. cremoris according to the Bergeys Mannual Systematic Bscteriology based on its morphological, cultural, physiological characteristics and biological system Antimutagenic activity of Leu. mesenteroides subsp. cremoris DLAB19 was found in the culture supernatant suggesting the bacterium secretes, the antimutagenic substance in the media. The antimutagenic activity of Leu. mesenteroides subsp. cremoris DLAB19 was reconfirmed by the spore-rec assay using spores of Bacillus subtilis H17 (Rec$^{+}$) and M45 (Rec$^{[-10]}$ ).).

• Journal of Chest Surgery
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• v.41 no.1
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• pp.137-140
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• 2008

Puimonary Langerhans cell histiocytosis is very rare, especially when accompanied by active pulmonary. tuberculosis. A patient was hospitalized due to excessive dyspnea and she was diagnosed with active pulmonary tuberculosis by a sputum AFB smear. The HRCT taken after hospitalization showed multiple micronodules and tiny cysts. An open lung biopsy confirmed the coexistence of pulmonary Langerhans cell histiocytosis.