• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.1
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• pp.29-35
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• 2023

Purpose The concentration of PSA (Prostate Specific Antigen) after radical prostatectomy in prostate cancer patients is a predictor of biochemical recurrence, and the AUA (American Urological Association) is defined as biochemical recurrence when the concentration of PSA is measured at 0.2 ng/mL or more, and when the concentration is measured at 0.2 ng/mL or more at the retest. This standard is also applied our hospital. In this laboratory, the PSA reagent using IRMA (Immunoradiometric Assay) is used, and the sensitivity at a very low value was not as good as the reagent used in the department of laboratory medicine. This study aims to increase the reliability of the results by improving the precision and sensitivity of very low values. Materials and Methods As a reagent for the study, PSA reagent using IRMA was used. As a method to improve the precision and sensitivity of very low values, a variation method on the serum volume(25 uL, 50 uL, 100 uL, 200 uL) was studied, and variation usefulness evaluation was conducted. The evaluation items were compared the results of precision, analytical sensitivity, recovery rate, dilution test, high-dose hook effect test, parallel test and very low concentration values(n = 20). Results The validation results were displayed in the order of 25 uL, 50 uL, 100 uL, 200 uL. As the serum volume increased, it was confirmed that CV (Coefficient of Variation)(%) improved. Analytical sensitivity(ng/mL) was 0.038, 0.041, 0.017, 0.015 and recovery rate(%) was 101±3, 101±3, 99±2, 97±4. very low concentration values(ng/mL) between each volume(n=20) were 0.135±0.068, 0.076±0.050, 0.048±0.034, 0.046±0.034. and high dose hook effect appeared as the serum volume increased. Conclusion Through the variation usefulness evaluation, it was confirmed that as the serum volume increased, the precision and sensitivity improved at very low concentration values. However, it is necessary to pay special attention to the occurrence of high-dose hook effect as the serum volume increases. In the case of tests that requires very low concentration values, it is thought that the reliability of the result will be increased if the variation method is properly used after the variation usefulness evaluation.

• Toxicological Research
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• v.35 no.3
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• pp.215-224
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• 2019

As various populations are rapidly becoming an aging society worldwide and interest in health issues has increased, demand for functional foods including herbal products has increased markedly to maintain a healthy state which has led to safety issues about their intake as an inevitable result. The objective of this study was to identify the safety profile of a Korean red ginseng and Salvia plebeia R. Br. extract mixture (KGC-03-PS) which is a valuable ingredient that can be used as a functional food. In the present study, the subacute oral toxicity and bacterial reverse mutagenicity of KGC-03-PS were evaluated. Sprague Dawley rats were administered KGC-03-PS orally for 28 days by gavage. Daily KGC-03-PS dose concentrations were 0, 500, 1,000, or 2,000 mg/kg body weight (bw) per day. Bacterial reverse mutation test with KGC-03-PS dose levels ranging from 312.5 to $5,000{\mu}g/plate$ was carried out by OECD test guideline No. 471. Five bacterial strains (Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2) were tested in the presence or absence of metabolic activation by plate incorporation method. There were no toxicological effects related with test substance in the clinical evaluation of subacute oral toxicity test including clinical signs, body weight, and food consumption. Moreover, no toxicological changes related to KGC-03-PS were observed in the hematological and serum biochemical characteristics as well as in the pathological examinations, which included organ weight measurements and in the gross- or histopathological findings. KGC-03-PS did not induce an increase in the number of revertant colonies in all bacterial strains of the bacterial reverse mutation test. The no-observed-adverse-effect level of KGC-03-PS is greater than 2,000 mg/kg bw/day, and KGC-03-PS did not induce genotoxicity related to bacterial reverse mutations under the conditions used in this study.

• Journal of Microbiology and Biotechnology
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• v.7 no.5
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• pp.323-328
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• 1997

The recombinant Escherichia coli BL21(DE3)pLysE : pTCGT1 was grown to overproduce Bacillus macerans cyclodextrin glucanotransferase (CGTase) able to synthesize ${\alpha}$-cyclodextrin (CD) with a selectivity of 67%. A number of batch fermentations were performed to test the possibility of using lactose as an inducer of the E. coli T7 promoter system. A mixture of isopropyl ${\beta}$-D-thiogalactoside (IPTG) and lactose (1 : 1) gave a maximum CGTase activity of 2.4 U/ml, which was higher than the value obtained with induction by IPTG alone. Fed-batch fermentations involving a glucose-controlled growth period followed by a gene-expression phase with mixtures of IPTG and lactose were employed to achieve high cell density and thereby increase total CGTase activity. Optimized fed-batch fermentation using the modified inducer (IPTG : lactose=1 : 3) and 100 g/l yeast extract solution in the gene-expression phase resulted in a maximum CGTase activity of 62.9 U/ml and a final cell mass of 53.5 g/l, corresponding to a 31-fold increase in CGTase activity and a 29-fold increase in cell mass compared with the control batch fermentation.

• Journal of Engineering Education Research
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• v.9 no.4
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• pp.10-18
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• 2006

Today it is critical for all engineers to have the capability of interacting in teams with members of different background and to meet the challenges that they will encounters in their careers. To satisfy such needs multidisciplinary engineering-design courses are attracting more attentions than ever in the engineering education community. In this paper we analyze the learning effectiveness of interdisciplinary design teams in an engineering design course in Dongguk University. The comparison analysis between monodisciplinary teams and interdisciplinary ones demonstrates higher learning effectiveness of interdisciplinary teams. In addition, the student evaluation of learning effectiveness points out that communication skill is one of the most important factors for a successful project. Such results show that multidisciplinary design courses must gain wider acceptance in engineering education and engineering students must have more chances to experience multidisciplinary teamwork.

• Journal of Microbiology
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• v.33 no.2
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• pp.154-159
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• 1995

SH-14, a novel killer strain of Ustilago maydis was isolated in Korea. It has been reported in other papers that the toxin specificity and double-stranded RNA pattern of SH-14 strain were different from other laboratory strains. In this paper, we analyzed the biochemical characteristics of U. maydis SH-14 virus. Three distinctive peaks were isolated from CsCl density gradient, designated as top (T), intermediate (I) and bottom (B) components. We found that the densities of each components, 1.285, 1.408 g/cm$\^$3/, respectively, are very similar to those of other strains. As previously reported by the analysis of dsRNA in each component, the dsRNA segments are separately encapsidated. Capsid protein of SH-14 virus consists of two proteins about 70 Kd shown by SDS-PAGE analysis. Electron microscopic examination of the virus particles revealed that UmV particles are very similar in size and morphology to all isolates as well as all lab-strains. In order to test immunological cross reactivity of UmV, werstern bolt analysis was carriedout with antiserum against A8 virus. All capsid protein had positive reaction against A8 antibody which indicated that UmV are immunologically cross-reactive with all isolates from Korea. The results presented in this paper may show that UmV isolated from SH-14 strain has very similar biochemical characteristics to those of other UmV. However, the difference in the toxin specificity and the molecular weight of toxin protein from the SH-14 strain has us to conclude that U. maydis SH-14 strain is a new killer type.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.241-249
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• 2010

Two groups of entomopathogenic bacteria, Xenorhabdus and Photorhabdus, are known to suppress insect immune responses by inhibiting eicosanoid biosynthesis. This study used these bacterial culture broths to develop novel biochemical insecticides against the diamondback moth, Plutella xylostella. Though the bacterial culture broths alone showed little insecticidal activity, they significantly enhanced pathogenicity of Bacillus thuringiensis against the fourth instar larvae of P. xylostella. Sterilization of the bacterial culture broth by autoclaving or $0.2\;{\mu}m$ membrane filtering did not influence the synergistic effect on the pathogenicity of B. thuringiensis. Three metablites identified in the culture broth of X. nematophila also showed similar synergistic effects. In field test, both entomopathogenic bacterial culture broth also enhanced the control efficacy of B. thuringiensis against P. xylostella.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.1
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• pp.31-42
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• 1998

A fundamental study on methane conversion for the collection organic wastes of agriculture, forestry and fishers was performed in a laboratory scale. As a result, selected Run B sample were obtained 18.41 C/N Ratio and 168.96 mg/L TCOD; Under the biochemical methane potential test, theoretical and actual methane generation was 313.6 mg/L VS added and 234.2 mg/L VS added, respectively; However, methane conversion from Run B were occurred 74% by anaerobic digestion. By the first order reaction kinetics, kinetic constant were $0.2476d^{-1}$ for Run B. Three steps fill-up filter reactor was evaluated methane content 16% up to promote than blank reactor; TCOD and SCOD have reduced 44.7% and 44.2%, respectively.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.110-118
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• 2018

Purpose: In this study, the potential for biogas production, degradation rates, and lag-phase of diauxic growth of carbohydrate-based material, which is one of the proximate compositions, were investigated. Methods: This study was conducted using starch as a carbohydrate-based material. In experimental condition 1, the biogas potential of carbohydrate-based material was measured. In experimental condition 2, the effect of feed to microorganism ratio (F/M ratio) on lag-phase of diauxic growth from carbohydrate-based material was tested. Biochemical methane potential tests were performed at five different feed to microorganism ratios (0.2, 0.4, 0.6, 0.8, and 1.0) under mesophilic conditions. The biogas production patterns, lag-phase, total volatile fatty acids to total alkalinity ratio (TVFA/TA ratio), and time required for 90 percent biogas production were used to evaluate biogas production based on the biochemical methane potential tests. Results: In experimental condition 1, unlike previous studies, biogas was produced in the TVFA/TA ratio ranging from 1.131 to 2.029 (approximately 13-19 days). The methane content in the biogas produced from the digesters was 7% on day 9 and increased rapidly until approximately day 27 (approximately 72%). In experimental condition 2, biogas yield was improved when the feed to microorganism ratio exceeded 0.6, with an initial lag-phase. Conclusions: Even if the TVFA/TA ratio was greater than 1.0, the biogas production was processed continuously, and the $CO_2$ content of the biogas production was as high as 60%. The biogas yield was improved when the F/M ratio was increased more than 0.6, but the lag-phase of carbohydrate-based material digestion became longer starting with high organic loading rate. To clarify the problem of the initial lag-phase, our future study will examine the microbial mechanisms during anaerobic digestion.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.13-17
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• 2003

The studies were carried out to identification of biochemical characteristics and serogroup of 55 Vibrio cholerae non-01 isolated from sea waters and shellfish from Apr., 1996 to Nov., 1996 in Korea coastal, and clinical sources from 1984 to 1996 in Korea hospitals. The results were as followed: V. cholerae non-O1 isolated 21 (10%) of 206 samples and the distribution in Kusan area was highest (16%) compared with those of other area, and its were not isolated during low water temperature of 13-18$^{\circ}C$. Of 55 strains, a strain was delayed sucrose utilization for 48hr in the biochemical characteristics. Fifty five V. cholerae non-O1 were differentiated 15 types by serogroup test and O14 of sea waters were 76% of highest followed by 14 clinical sources were O8.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.37-45
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• 1995

The performance and the operational problems of UASB(Upflow Anaerobic Sludge Blanket) reactor for treatment of dairy wastewaters were investigated. Synthetic milk wastewater was successfully treated up to the loading rate of 3.9kg $COD/m^3.day$, with a specific gas production rate of 1. 23 I/I. day and a COD removal efficiency of over 90%. However, the sludge rising was observed at the loading rate of 2.1kg $COD/m^3.day$, due probably to the formation of scum layer at the surface of settling compartment. The BMP(biochemical methane potential) of raw milk wastewater and ice cream wastewater, measured by using SBT(serum bottle test), were 0.135 and 0.66ml $CH_4/mg\;COD_{added}$, respectively. The sludge activity increased more than 8 times from 0.159g $COD-CH_4/g$ VSS. d during 90 days of operation.