• Horticultural Science & Technology
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• v.33 no.1
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• pp.70-82
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• 2015

This study was conducted to establish an efficient screening system to identify melon resistant to Fusarium oxysporum f. sp. melonis. F. oyxsporum f. sp. melonis GR was isolated from infected melon plants collected at Goryeong and identified as F. oxysporum f. sp. melonis based on morphological characteristics, molecular analyses, and host-specificity tests on cucurbits including melon, oriental melon, cucumber, and watermelon. In addition, the GR isolate was determined as race 1 based on resistance responses of melon differentials to the fungus. To select optimized medium for mass production of inoculum of F. oxysporum f. sp. melonis GR, six media were tested. The fungus produced the most spores (microconidia) in V8-juice broth. Resistance degrees to the GR isolate of 22 commercial melon cultivars and 6 rootstocks for melon plants were investigated. All tested rootstocks showed no symptoms of Fusarium wilt. Among the tested melon cultivars, only three cultivars were susceptible and the other cultivars displayed moderate to high resistance to the GR isolate. For further study, six melon cultivars (Redqueen, Summercool, Superseji, Asiapapaya, Eolukpapaya, and Asiahwanggeum) showing different degrees of resistance to the fungus were selected. The development of Fusarium wilt on the cultivars was tested according to several conditions such as plant growth stage, root wounding, dipping period of roots in spore suspension, inoculum concentration, and incubation temperature to develop the disease. On the basis of the test results, we suggest that an efficient screening method for melon plants resistant to F. oxysporum f. sp. melonis is to remove soil from roots of seven-day-old melon seedlings, to dip the seedlings without cutting in s pore s uspension of $3{\times}10^5conidia/mL$ for 30 min, to transplant the inoculated seedlings to plastic pots with horticulture nursery media, and then to cultivate the plants in a growth room at 25 to $28^{\circ}C$ for about 3 weeks with 12-hour light per day.

• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.60-66
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• 2014

This test was performed to evaluate the bactericidal efficacy of a fumigation disinfectant containing 20% ortho-phenylphenol against Pseudomonas aeruginosa (P. aeruginosa) and Enterococcus hirae (E. hirae). In preliminary tests, P. aeruginosa and E. hirae working culture suspension number (N value) were $2.8{\times}10^8$ and $4.0{\times}10^8CFU/mL$, respectively. And all the colony numbers on the carriers exposed to the fumigant (n1, n2, n3) were higher than 0.5N1 (the number of bacterial test suspentions by pour plate method), 0.5N2 (the number of bacterial test suspentions by filter membrane method) and 0.5N1, respectively. In addition, the mean number of P. aeruginosa and E. hirae recovered on the control-carriers (T value) was $2.8{\times}10^8$ and $3.4{\times}10^6CFU/mL$, respectively. In the bactericidal effect of the fumigant, the reduction number of $2.8{\times}10^8$ (d value) was 6.46 and 5.19 logCFU/mL, respectively. According to the French standard for the fumigant, the d value for the effective bactericidal fumigant should be over than 5 logCFU/mL. With the results from this study, the fumigation disinfectant containing 20% ortho-phenylphenol has an effective bactericidal activity, then the fumigant can be applied to disinfect food materials and kitchen appliances contaminated with the pathogenic bacteria.

• Journal of Gifted/Talented Education
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• v.13 no.4
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• pp.65-94
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• 2003

The purpose of this study is to acquire the information on the current situation of students' selection process in order to renovate the system of picking up the students. As a first step of the study, we examined the validity of the factors of the single-out system such as qualification and the process for the application and the standards and proceeding of the selection. Then we analysed the result of the entrance examination of Hansung Science Highschool in 2002. The analysis was on the correlation between the result of entrance examination and the achievement in the school and the decision of the course after graduation. To know on the achievement of the students, we investigated the records of regular tests and asked the teachers' opinion in math and science classes. As a result, we gained the following points: First, the present single-out system has a danger of excluding students who are much talented in science and math field because it is based on students' achievements in middle schools; Second, the new selection system should consider the character and attitude of the applicants in addition to their knowledge; Third, the continuous observation of the teacher in middle school should be an important factor of the picking up system; Fourth, more questions requiring divergent thinking ability and inquiry skill should be developed as selective examination question. Also examination questions should cover the various contents from mathematics to science, and do not affect pre-learning; Finally, the system of present letting all students stand in one line should be changed into that of letting students in various lines. We can consider using multi-step selection system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.228-234
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• 2016

The aim of this study was to develop pharmaceutical dosage forms with a bi-phasic drug using a double extrusion approach. Hot melt extrusion was performed using a co-rotating twin-screw extruder. The. 1st melt extrusion was performed using polymer with a relatively higher Tg, such as HPMC and the 2nd melt extrudate was obtained using the 1st extrudate and polymers with a lower Tg, such as HPMC-AS and PEO. In addition, the formulation with all the content in the same proportion as the double extudate was produced using single extrusion for comparison. Physical characterization was performed on the formulations employing differential scanning calorimetry (DSC). In vitro release tests were studied using a USP Type-I apparatus at $37{\pm}0.5^{\circ}C$ and 100 rpm. The similarity factor (f2) was also used to check the difference statistically. The DSC results indicated that the crystallinity of ibuprofen was changed to an amorphous state after extrusion in both double and single melt extrusion. Double melt extrudate with ibuprofen showed the desired release in acidic media (pH 1.2) in the first two hours and basic (pH 6.8) during six hours. Double melt extrudate with glimepiride showed faster release in 60 min of over 80%, whereas the single extrudate with glimepiride showed retarded release due to the interaction with HPMC. The similarity factor(f2) value was 28.5, which demonstrates that there were different drug release behavior between the double and single extrusion. Consequently, the double melt extrudated formulation was robust and gave the desired drug release pattern.

• Journal of Nutrition and Health
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• v.46 no.2
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• pp.177-185
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• 2013

The purpose of this study was to analyze the nutritional status of Chinese female college students in Korea, and to investigate changes in their dietary behavior after residing in Korea. The subjects included 114 Chinese female college students currently studying in Korea. General characteristics and dietary behaviors before and after residing in Korea were investigated. Daily nutrients and food intake were assessed using a one-day 24-hour recall. Consumption of most nutrients, namely calcium, iron, zinc, vitamin $B_2$, vitamin C, and folate was estimated to fall below the EAR for the Korean population. The proportions of subjects whose intake were estimated below the EAR for folate, calcium, vitamin $B_2$, iron, zinc, and vitamin C were 93.0%, 71.9%, 66.7%, 65.8%, 65.8%, and 63.2%, respectively. In the current study, the dietary behavior scores fell significantly after Chinese students immigrated to Korea (p < 0.001); increased frequency of meal skipping, less consumption of fruits and vegetables, irregular meal pattern, and imbalanced diet were some of the significant changes among Chinese students before and after residing in Korea. In addition, consumption of most nutrients, including dietary fiber, vitamin A, vitamin B group, vitamin C, and folate in the Worsened Group was significantly lower, compared with the No Change Group (p < 0.05). According to the changes in dietary behaviors, consumption of most nutrients, including dietary fiber, vitamin A, vitamin B group, vitamin C, and folate in the Worsened Group was significantly lower than in the No Change Group (p < 0.05). In conclusion, these results indicated that Chinese students practiced more unhealthy dietary behaviors after residing in Korea and Chinese students residing in Korea showed poor nutrient-based diet quality. Conduct of a follow-up study using blood profile tests is needed in order to assess the nutritional status of Chinese students. These results would be used in planning of a nutritional surveillance program for Chinese students.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.73-82
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• 2012

Allele information from the analysis of the 13 microsatellite (MS) markers, were classified into the $F_0$, $F_1$ and $F_2$ generations, and probabilities of the same individual emergency in each generation was calculated. As a result, the 13 MS markers showed an estimate of $3.84{\times}10^{-23}$ on the premise of the randomly mated group of $F_2$, which implies that the same individuals may emerge by the use of 37 kinds of SNP markers. In this study, the experimental pigs were intercross between only 2 breeds (Korean native pig and Landrace). In addition, the success rate of paternity tests was analyzed on the whole group, by the use of the 13 MS markers and 37 SNP markers. As regards the exclusionary power of the second parent ($PE_{pu}$), MS markers and SNP markers showed 0.97897 and 0.99149, respectively. In relation to the parent exclusion power of both parent (PE), MS markers and SNP markers showed 0.99916 and 0.99949, respectively. In the case of the estimate to identify parental candidates that had the highest probability ($PNE_{pp}$), the two showed 1.00000 all. The Korean pig industry tends to mass produce hogs with limited numbers of alleles in limited parents. Such being the case, there is a need to organize a marker, for which it is imperative to find markers with high efficiency and high economic feasibility of the characteristics of DNA markers, sample size, the accuracy and expenses of genotyping cost, the manageability of data and the compatibility among analysis systems.

• Food Science and Preservation
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• v.15 no.5
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• pp.743-748
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• 2008

Amyloid $\beta$ peptide ($A{\beta}$) is known to increase oxidative stress in nerve cells, leading to apoptosis that is characterized by free radical formation and lipid peroxidation. Neurodegenerative diseases such as Alzheimer's disease (AD) are characterized by large deposits of $A{\beta}$ in the brain. In our study, neuronal protective effects of green tea, along with water activity (0.813), and leaf storage periods (fresh leaf, or leaf stored for up to 4 weeks) were investigated. We measured protective effects against $A{\beta}$-induced cytotoxicity in neuron-like PC12 cells. Powdered green tea was extracted with distilled water at $70^{\circ}C$ for 5 min, and this extract was freeze-dried and stored at $-20^{\circ}C$ until use. In cell viability assays using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), the fresh extract, and that obtained after 1 week of leaf storage, showed the best protective effects against $A{\beta}$-induced neurotoxicity. As oxidative stress causes membrane breakdown, the protective effect of green tea extracts was investigated using lactate dehydrogenase (LDH) and trypan blue exclusion assays. LDH release into the medium was inhibited (by 20-25%) in all tests. In addition, all green tea extracts (fresh, or stored before extraction for up to 4 weeks) showed better cell protective effects ($93.3{\pm}1.8-96.2{\pm}2.4$) than did vitamin C ($91.0{\pm}1.6$), used as a positive control. The results suggest that effectiveness of green tea extracts falls with prolonged leaf storage.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.451-464
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• 2022

The high-level nuclear waste repository is a deep geological disposal system exposed to complex environmental conditions such as high temperature, radiation, and ground-water due to handling spent nuclear fuel. Continuous exposure can lead to cracking and deterioration of the structure over time. On the other hand, the high-level nuclear waste repository requires an ultra-long life expectancy. Thus long-term structural health monitoring is essential. Various sensors such as an accelerometer, earth pressure gauge, and displacement meter can be used to monitor the health of a structure, and a piezoelectric sensor is generally used. Therefore, it is necessary to develop a highly durable sensor based on the durability assessment of the piezoelectric sensor. This study designed an accelerated life test for durability assessment and life prediction of the piezoelectric sensor. Based on the literature review, the number of accelerated stress levels for a single stress factor, and the number of samples for each level were selected. The failure mode and mechanism of the piezoelectric sensor that can occur in the environmental conditions of the high-level waste repository were analyzed. In addition, two methods were proposed to investigate the maximum harsh condition for the temperature stress factor. The reliable operating limit of the piezoelectric sensor was derived, and a reasonable accelerated stress level was set for the accelerated life test. The suggested methods contain economical and practical ideas and can be widely used in designing accelerated life tests of piezoelectric sensors.

• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• Food Engineering Progress
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• v.15 no.1
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• pp.56-63
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• 2011

Durum wheat semolina was added into wet-milled rice flour in order to improve chewy texture, firm bite ("al dente"), and resistance to overcooking of the ordinary rice noodles. Wet noodles were prepared by mixing 0 (control), 5, 10, 15, and 20% (w/w) of semolina per semolina and rice flour mixtures. Vital gluten (4%, w/w) and salt (2%, w/w) were added to form the pliable strands of wet noodles and final moisture contents of the raw mixtures were equalized at 45%. Pasting properties of the suspended flour mixtures as measured by the Rapid Visco Analyser (RVA) showed slight increases (up to $1.2^{\circ}C)$ in pasting temperatures along with the considerable decreases in peak viscosities as semolina increased at over 15%. Reduced shear thinning and retrogradation of the starch solution that leads to hardening of the cooked noodles were indicated by lowered breakdown viscosities and gaps between finaland setback viscosities from the RVA viscogram as semolina increased at over 10%. Reduced water uptake and turbidity increases of the cooking water as caused by the soluble starches from the noodle were also noted as the content of semolina increased. More or less significant (p<0.05) decreases in colorimetric L (lightness) value of the raw- and cooked noodles were observed as semolina increased while a- (redness) and b (yellowness) values were rather increased at the same moment. Textural properties of the cooked noodles such as hardness, springiness, cohesiveness, gumminess, and chewiness from TPA tests were significantly (p<0.05) influenced by added semolina, even at 5%-levels or more. It can be concluded that addition of semolina into rice flour could provide easy handling of the wet noodles without distortion during transportation, integrity and firm bite of the cooked noodles, and less loss of starch to the cooking water in comparison with the ordinary rice noodle. It was finally suggested that optimum level of the semolina in the product was approximately 10% for the quality wet rice noodle products.