• Food Science of Animal Resources
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• v.35 no.6
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• pp.738-747
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• 2015

Angiotensin-converting enzyme (ACE) inhibitory activity was evaluated for the low-molecular-weight fraction (<3 kDa) obtained from milk fermentation by Bifidobacterium longum KACC91563. The ACE inhibitory activity in this fraction was 62.3%. The peptides generated from the <3 kDa fraction were identified by liquid chromatography-electrospray ionization quantitative time-of-flight mass spectrometry analysis. Of the 28 peptides identified, 11 and 16 were identified as β-casein (CN) and α_s1-CN, respectively. One peptide was identified as κ-CN. Three peptides, YQEPVLGPVRGPFPIIV, QEPVLGPVRGPFPIIV, and GPVRGPFPIIV, from β-CN corresponded to known antihypertensive peptides. We also found 15 peptides that were identified as potential antihypertensive peptides because they included a known antihypertensive peptide fragment. These peptides were as follows: RELEELNVPGEIVE (f1-14), YQEPVLGPVRGPFP (f193-206), EPVLGPVRGPFPIIV (f195-206), PVLGPVRGPFPIIV (f196-206), VLGPVRGPFPIIV (f197-206), and LGPVRGPFPIIV (f198-206) for β-CN; and APSFSDIPNPIGSENSEKTTMPLW (f176-199), SFSDIPNPIGSENSEKT- TMPLW (f178-199), FSDIPNPIGSENSEKTTMPLW (f179-199), SDIPNPIGSENSEKTTMPLW (f180-199), DIPNPIGSENSEKTTMPLW (f181-199), IPNPIGSENSEKTTMPLW (f182-199), PIGSENSEKTTMPLW (f185-199), IGSENSEKTTMPLW (f186-199), and SENSEKTTMPLW (f188-199) for α_s1-CN. From these results, B. longum could be used as a starter culture in combination with other lactic acid bacteria in the dairy industry, and/or these peptides could be used in functional food manufacturing as additives for the development of a product with beneficial effects for human health.

• Education of Primary School Mathematics
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• v.11 no.1
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• pp.1-19
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• 2008

This study analyzed the repeated error patterns in division of fraction by elementary students through observation of their test papers. The questions for this study were following. First, what is the most changable thing among the repeated error patterns appeared in division of fraction by elementary students? Second, what is the most frequent error patterns in division of fraction by elementary students? First of all, the ratios of incorrect answers in division of fraction by general students were researched. This research was the only one time. The purpose was to know what kind of compositions in the problems were appeared more errors. Total 554 6th grade students(300 boys and 254 girls) from 6 elementary schools in Seoul are participated in this research. On the basis of this, the study for analysis began in earnest. 5 tests made progress for about 4 months. Total 181 6th grade students(92 boys and 89 girls) from S elementary school in Seoul were participated in this. After each test, to confirm the errors and to classify them were done. Then the repeated error patterns were arranged into 4 types: alpha, beta, gamma and delta type. Consequently, conclusions can be derived as follows. First, most students modify their errors as time goes by even though they make errors about already learned contents. Second, most students who appeared errors make them continually caused a reciprocal of natural number in the divisor when they calculate computations about '(fraction) $\div$ (natural number)'. Third, most students recognize that the divisor have to change the reciprocal when they calculate division of fraction through they modify their errors repeatedly.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.56-63
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• 2003

Fractional composition and mobility of sediments some heavy metals in Okdong stream are investigated. The fractional scheme for sediment heavy metal was made for five chemically defined heavy metal forms as adsorbed fraction, carbonate fraction, reducible fraction, organic fraction, and residual fraction (Tessier et at., 1979). The most abundant fraction of the sediment heavy metal is reducible and secondly abundant organic fraction. Adsorbed fraction is minor part of the total heavy metals. Mobilization of sediment heavy metals in stream Okdong is occur 19.8∼56.7% of total cadmium concentrate. The most abundant fraction of the sediment metal is organic fraction in Cu, Pb metals investigated. Labile fraction of sediment metals are 0.5%∼48.5% of total Zn, 2.6%∼48.1% of total Pb, 0.2∼36.9% of total Cu respectively, Most of labile fraction consists of reducible fraction for Cd, Zn, adsorbed fraction for Pb, reducible fraction for Cu, adsorbed fraction for Ni. The Mobilization of Zn and Cu is most likely to occur when oxygen depletes and that of Pb and Ni occurs when physical impact, oxygen depletion and pH reduction.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1314-1319
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• 2011

This study was carried out to investigate the surface soil organic carbon fractions affecting by different land use types, including needle-leaf forest (FN), broad-leaf forest (FB), pasture, annual upland cropping land (upland), and paddy rice land (paddy). We chose seven regions across Korean inland, considering sea level altitude, and measured soil organic carbon content and physico-chemical properties such as bulk density at a depth of 0~15 cm using core samples in April for the each land use type. In addition, labile organic carbon fractions in soil including light fraction and hot water extractable carbon were investigated. From this study, organic carbon storage (Mg C per ha) in the upper 15-cm soils was highest in FB (37.8), and decreased in the order of pasture (29.1), FN (28.8), paddy (21.9), and upland crop (19.9). In forest, more than 20% of soil organic carbon existed as light fraction, the free organic matter. Hot-water extractable carbon contents of soils in five land use types were lower than 7% of their soil organic carbon content.

• Journal of Educational Research in Mathematics
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• v.24 no.2
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• pp.165-180
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• 2014

This study analyzed in what ways the instructional materials have been dealing with the fraction as quotient, since the seventh national mathematics curriculum. An analysis of this study urged us to re-consider the content related to the fraction as quotient. First, the fraction as quotient has weakened in the current mathematics textbooks and workbooks in comparison to those developed under the previous curriculum. Second, the contexts of whole number division taught in grades 3 and 4 were not naturally connected to those of the fraction as quotient taught in grade 5. Third, the types of word problems, visual models, and partitioning strategies in the textbooks and the workbooks were partial, and the process of formalization was limited. Building on these results, this study is expected to suggest specific implications which may be taken into account in developing new instructional materials in process.

• The Mathematical Education
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• v.52 no.2
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• pp.217-230
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• 2013

This study attempts to propose the construction of textbook contents of fraction division and to suggest a method to strengthen the connection among problem context, manipulation activities and symbols by proposing an algorithm of dividing fractions based on problem contexts. As showing the suitable algorithm to problem context, it is able to understand meaningfully that the algorithm of fractions division is that of multiplication of a reciprocal. It also shows how to deal with remainder in the division of fractions. The results of this study are expected to make a meaningful contribution to textbook development for primary students.

• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.241-244
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• 2008

Methanol extracts were prepared from Z. schinifolium leaf and successively fractionated with chloroform, butanol, and water. The butanol fraction exhibited the highest antioxidative activities. Therefore the butanol fraction was purified and a chemical structure was identified by $^1H-^{13}C-NMR$ spectra, and FT-IR. The isolated antioxidative substance was identified as quercitrin.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.622-627
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• 2013

Colloidal silica is used in various industrial products such as chemical mechanical polishing slurry for planarization of silicon and sapphire wafer, organic-inorganic hybrid coatings, binder of investment casting, etc. An accurate determination of particle size and dispersion stability of silica sol is demanded because it has a strong influence on surface of wafer, film of coatings or bulks having mechanical, chemical and optical properties. The study herein is discussed on the effect of measurement results of average particle size, sol viscosity and electrophoretic mobility of particle according to the volume fraction of eight types of silica sol with different size and surface properties of silica particles which are presented by the manufacturer. The measured particle size and the mobility of these sol were changed by volume fraction or particle size due to highly active surface of silica particle and change of concentration of counter ion by dilution of silica sol. While in case the measured sizes of small particles less than 60 nm are increased with increasing volume fraction, the measured sizes of larger particles than 60 nm are slightly decreased. The mobility of small particle such as 12 nm are decreased with increase of viscosity. However, the mobility of 100 nm particles under 0.048 volume fraction are increased with increasing volume fraction and then decreased over higher volume fraction.

• Journal of Soil and Groundwater Environment
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• v.20 no.2
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• pp.47-54
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• 2015

The objective of this study was to optimize the experimental conditions for bioleaching of arsenic (As) using Herbaspirillum sp. GW103 and to understand the interaction between bacteria and As during bioleaching. Five variables, temperature, time, CaCO₃, coconut oil cake, and shaking rate, were optimized using response surface methodology (RSM) based Box-Behnken design (BBD). Maximum (73.2%) bioleaching of As was observed at 30℃, 60 h incubation, 1.75% CaCO₃, 3% coconut oil cake, and 140 rpm. Sequential extraction of bioleached soil revealed that the isolate Herbaspirillum sp. GW103 significantly reduced 28.6% of water soluble fraction and increased 38.8% of the carbonate fraction. The results of the study indicate that the diazotrophic bacteria Herbaspirillum sp. could be used for bioleaching As from mine soil.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.2
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• pp.43-50
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• 2008

In this paper we suggest the methods that compute the total inventory cost based on EOQ and the total inventory cost based on OMMIP. The total inventory cost consists of purchasing cost, ordering cost, inventory holding cost, stockout cost and so on. This papers also proposes the method that decides optimum order quantity as the order amount to minimize the total inventory cost with comparison of EOQ total inventory cost and OMMIP total inventory cost according to inventory holding cost as a fraction of unit cost.