• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.265-270
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• 2017

A key virulence factor for urinary tract pathogens is the enzyme urease, which catalyzes the hydrolysis of urea into ammonium ions and carbonic acid. Urease activity plays an important role in the pathogenesis of urinary tract infection. In this study, the inhibitory effect of zerumbone against six urease-producing bacteria (Klebsiella oxytoca, K. pneumoniae, Morganella morganii, Proteus mirabilis, P. vulgaris, and Staphylococcus saprophyticus) and their urease activities were evaluated. The results of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests showed that zerumbone had antibacterial effect against these six urease-producing bacteria. The MIC and MBC of zerumbone ranged from 0.5 to 2 mM and 1 to 4 mM, respectively. In the urease inhibitory assay, zerumbone showed better urease inhibition ($56.28{\pm}2.45-37.83{\pm}3.47%$) than the standard urease inhibitor, acetohydroxamic acid ($40.46{\pm}1.94-22.99{\pm}3.53%$). However, zerumbone did not affect the levels of the urease subunit. These results clearly indicated that zerumbone has antibacterial potential against urease-producing bacteria and possesses excellent bacterial urease inhibition properties.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.12
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• pp.109-120
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• 1998

An image segmentation approach based on the fuzzy worm searching and MIN-MAX clustering algorithm is proposed in this paper. This algorithm deals with fuzzy worm value and min-max node at a gross scene level, which investigates the edge information including fuzzy worm action and spatial relationship of the pixels as the parameters of its objective function. But the conventional segmentation methods for edge extraction generally need the mask information for the algebraic model, and take long run times at mask operation, whereas the proposed algorithm has single operation according to active searching of fuzzy worms. In addition, we also propose both genetic fuzzy worm searching and genetic min-max clustering using genetic algorithm to complete clustering and fuzzy searching on grey-histogram of image for the optimum solution, which can automatically determine the size of ranges and has both strong robust and speedy calculation. The simulation results showed that the proposed algorithm adaptively divided the quantized images in histogram region and performed single searching methods, significantly alleviating the increase of the computational load and the memory requirements.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.161-171
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• 2021

This paper presents the findings of a comparative study on minimum weight design and sensitivity evaluation using different experimental design methods for the structural design of an active-type deck support frame (DSF) developed for the float-over installation of an of shore plant topside. The thickness sizing variables of the structural members of a passive-type DSF were considered the design factors, and the output responses were defined using the weight and strength performances. The design of the experimental methods applied in the comparative study of the minimum weight design and the sensitivity evaluation were the orthogonal array design, Box- Behnken design, and Latin hypercube design. A response surface method was generated for each design of the experiment to evaluate the approximation performance of the design space exploration according to the experimental design, and the accuracy characteristics of the approximation were reviewed. Regarding the minimum weight design, the design results, such as numerical costs and weight minimization, of the experimental design for the best design case, were evaluated. The Box- Behnken design method showed the optimum design results for the structural design of the passive-type DSF.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.295-306
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• 2009

The risk assessment of groundwater and soil in Sasang industrial complex in Busan Metropolitan City was carried out in order to estimate risks to human health and the environment. The carcinogenic risk (CR) of receptors to soil and air was not identified. However, the CRs for TCE and PCE were 6.7E-6 and 1.0E-5, respectively. Hazard quotient (HQ) and hazard index (HI) did not appear through air exposure pathways. Yet the HQ and HI of soil were 3.4E-5 and 5E-5, respectively, and lower than the critical value (1.0). On the contrary, HQ and HI with respect to groundwater were calculated as 0.7 (not hazardous) and 1.4 (hazardous). The constituent reduction factor (CRF) for TCE in the study area was determined as 2.5, and thus remediation work is demanded. As a result of sensitivity analysis for 18 exposure factors, eight exposure factors (life time of carcinogens, age, body weight, exposure duration, exposure frequency, dermal exposure frequency, water ingestion rate, and soil ingestion rate) varied with the variation of risk.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.47-52
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• 2010

Physical, chemical and biological properties of soils and cadmium(Cd) content of Artemisia princeps var. orientalis collected from 10 metalliferous mines were analysed. Cd contents of unplanted soils and rhizosphere soils were not significantly different(p < 0.05), and mean values were 5.92 and 5.91 mg/kg, respectively. In addition, Cd content of rhizosphere soils were correlated with Cd content of Artemisia princeps (p < 0.05, ${R^2}_{shoot}$ = 0.3120, ${R^2}_{root}$ = 0.4177). Minimum data set(MDS) of soil quality parameters for statistical assessment of Cd uptake was established by principal component analysis, and it was identified as organic matter(OM), dehydrogenase activity(DHA), pH, exchangeable Mg. According to multiple regression analysis using the MDS, coefficients of determination ($R^2$) for Cd uptake of shoot and root of Artemisia princeps were found to be 0.3418 and 0.5121, respectively. This suggests that statistical soil quality assessment using the MDS seems a useful tool to interpret heavy metal uptake of plant.

• Journal of Life Science
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• v.18 no.11
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• pp.1507-1512
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• 2008

In spite of long research period for Salmonella typhi, little information is known about the pathogenesis mechanism of human typhoid fever caused by S. typhi due to lack of infection model in animals. A wild-type of S. typhi Ty2 strain requires cysteine to grow on minimal media. We hypothesized that this cysteine requirement may restrict colonization of S. typhi in animals during infection process. Among the S. typhi strains carrying Salmonella typhimurium genomic library, we have isolated three S. typhi transformants growing on minimal media without cysteine. Although there were three ORFs in DNA of pBP71, the STM1490 ORF complemented cysteine auxotrophy of S. typhi. Analysis of the deduced amino acid sequence of the STM1490 homolog in S. typhi revealed that there are differences in two amino acids. Plasmids containing amino acid substitutions in STM1490 supported S. typhi growth on minimal media without cysteine, indicating irrelevance of these two amino acids to STM1490 function. These results tells us that there are other factors or systems involved in cysteine requirement of S. typhi.

• Journal of Korea Water Resources Association
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• v.53 no.10
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• pp.903-915
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• 2020

Long-term high-resolution hydro-meteorological data has been recognized as an essential element in establishing the water resources plan. The increasing demand for spatial precipitation in various areas such as climate, hydrology, geography, ecology, and environment is apparent. However, potential limitations of the existing area-weighted and numerical interpolation methods for interpolating precipitation in high altitude areas remains less explored. The proposed PRISM (Precipitation-Elevation Regressions on Independent Slopes Model) model can produce gridded precipitation that can adequately consider topographic characteristics (e.g., slope and altitude), which are not substantially included in the existing interpolation techniques. In this study, the PRISM model was optimized with SCEM-UA (Shuffled Complex Evolution Metropolis-University of Arizona) to produce daily gridded precipitation. As a result, the minimum impact radius was calculated 9.10 km and the maximum 34.99 km. The altitude of coastal weighted was 681.03 m, the minimum and maximum distances from coastal were 9.85 km and 38.05 km. The distance weighting factor was calculated to be about 0.87, confirming that the PRISM result was very sensitive to distance. The results showed that the proposed PRISM model could reproduce the observed statistical properties reasonably well.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.50-55
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• 2009

Purpose : This study aimed to determine the influence of low-dose oxygen ($FiO_2$ <25%) therapy through nasal cannulae on the progress and prognosis of retinopathy of prematurity (ROP) as well as methods of preventing ROP. Methods : Our subjects comprised premature infants (gestation period <37 weeks; birth weight <1,750 g) born in Daegu Fatima Hospital between February 1, 2001 and January 31, 2006. We retrospectively reviewed and analyzed the medical records of 273 patients who were available for eye examination and follow up over 6 months. Results : The factors maximally influencing the occurrence of ROP were low gestation age and low birth weight. We observed that the incidence of ROP increased with the increasing duration of low-dose oxygen therapy. ROP onset was delayed during ongoing oxygen therapy; however, rapid progression of ROP occurred after the discontinuation of oxygen therapy among premature infants up to the prethreshold stage. Conclusion : To prevent of occurrence of severe ROP and its rapid progression, the period of low-dose oxygen therapy needs to be shortened. Moreover, frequent eye examinations should be performed after the discontinuation of oxygen therapy.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.987-993
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• 1996

This study was attempted to prepare milk and soymilk containing high number of viable cells of bifidobacteria during the fermentation as well as to establish the optimum condition for bacteria growth. Activity of ${\alpha}$- and ${\beta}-galactosidase$ produced by bifidobacteria was also determined. Milk and soymilk inoculated with Bifidobacterium longum ATCC 15707 were incubated in a nitrogen-carbon dioxide atmosphere at $37^{\circ}C$ for two days. and time courses of pH, acidity, viable cells and effect of growth factors were determined. After two days, pH of milk gradually decreased from 6.81 to 4.84 and pH of soymilk changed from 7.02 to 3.89. The viable cell numbers of bifidobacteria increased constantly in soymilk, while bacterial growth in milk appeared to be delayed after storage of two days. Both of ${\alpha}$- and ${\beta}-galactosidase$ activities were detected in soymilk, but activity of ${\beta}-galactosidase$ was predominant in milk. Fucosyllactose appeared to be a good growth factor in soymilk. During the fermentation of milk, L-cysteine HCl enhanced growth of bifidobacteria at the early stage and fucosyllactose was a good growth factor in the propagations of bifidobacteria from middle stage.

• Clinical and Experimental Pediatrics
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• v.51 no.11
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• pp.1179-1184
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• 2008

Purpose : Pulmonary interstitial emphysema (PIE) primarily occurs in preterm infants suffering from respiratory distress syndrome (RDS) and kept under mechanical ventilator care. Therefore, this study aimed to examine various risk factors for PIE, to identify conditions that can decrease the possibility of PIE development. Methods : PIE classification was conducted for 183 patients diagnosed to have RDS and receiving mechanical ventilator care with pulmonary surfactant between March 2000 and February 2007. The characteristics of each patient were analyzed through retrospective examination of their medical histories. Results : Among 183 patients, 17 had PIE; all factors, including birth weight, gestational age, RDS grade III or above, chorioamnionitis, and premature rupture of membranes, were statistically significant (P<0.05). The period of mechanical ventilator use was statistically significant, but the peak mean airway pressure and peak partial pressure of inspired oxygen were not. PIE mainly occurred on the right side or both sides rather than the left side and mostly developed within 72 h. The PIE group showed higher mortality rate than the control group, and the major cause of mortality was pneumothorax. Conclusion : Risk factors for PIE in infants suffering from RDS and kept under mechanical ventilator care include low gestational age, low birth weight, chorioamnionitis, and premature rupture of membranes. If any risk factors are noted, the infant must be observed closely for at least 72 h after birth.