• Journal of Nutrition and Health
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• v.21 no.2
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• pp.129-133
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• 1988

The lonitudinal determination of specific gravity, total solid and protein contents of human milk were carried out in 27 Korean women. Human milk samples from the subjects were collected at 15, 30, 60, 90, 120, 150th days of lactation. 1) The average values of specific gravity of the milk was 1, 0281 (S.D. 0.0018, n=12), with a range of 1.0200-1.0383. 2) The average values of total soild of the milk was 12.07g/100ml(S.D. 0.38, n=112), with a range of 9.36-15.88g/100ml. 3) The average values of protein content of the milk was 1.20g/100ml (S.D. 0.14, n=112), with a range of 1.09-1.46g/100ml. A slight decrease of specific gravity and protein content in human milk was found during the course of lactation, but significant decrease was not found in total solid content.

• Journal of Plant Biology
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• v.36 no.4
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• pp.363-370
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• 1993

Experiments with non-nodulated alfalfa (Medicago sativa L. cv, Europe) plants grown in hydroponic cuiture, were carried out to estimate the remobiJization of nitrogen (N) reserves and to investigate the transported forms of reduced soluble-N in xylem during regrowth following shoot removal. Endogenous N remobilization were estimated by $^{15}N$ labelling and amino acids in xylem sap were analysed. The, $^{15}N$ contents of ~egr9wing leaves and stems increased as a result of remobilization of N reserves mainly from root ,system, Regrowing leaves were a stronger sink than regrowing stems, with about tWo-thirds of remobilized 15N being recoved in leaves. Endogenous N in lateral roots accounted for about 46% of the total N reserves used for regrowth, while tap roots accounted for 23%, About 72% of total endogenous N remobilized to regrowing shoot, occurred during the first 10 days of regrowth, The outflow of reduced soluble-N (mainly amino acids) was greater than that of protein-N, while the latter was the largest storage pool in tap root and lateral roots. It is suggested that amino acids-N was the most readily avaiable form of N reserves. Asparagine, which repre5ented about 75% of amino acids-N in xylem sap, was the main transported form of reduced N. Its relative contents, during the first 10 days of regrowth, decreased from 75% to 59%. This decline was accompanied by compensatory increase in the relative contents of asparatate and glutamine.

• Polymer(Korea)
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• v.36 no.1
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• pp.111-116
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• 2012

A functionalization of mesoporous materials with organosilane was carried out via a post-synthesis grafting method and $(n-BuCp)_2ZrCl_2$/methylaluminoxane (MAO) as subsequently immobilized on the functionalized mesoporous materials for ethylene polymerization. Organosilanes having amine, cyano or imidazoline group such as $N$-[(3-trimethoxysilyl)propyl]ethylenediamine (2NS), 4-(triethoxysilyl)butyronitrile (1NCy), 1-(3-triethoxysilylpropyl)-2-imidazoline (2NIm) were used for the surface functionalization of mesoporous materials. In the SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ catalyst preparation, the amount of MAO in feed increased with an decrease in the Zr content of the supported catalyst, and Al content in the supported catalyst increased. The ethylene homopolymerization activity of SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ dramatically increased as the amount of MAO in feed increased. Furthermore, when the immobilization time was 6 hrs, SBA-15/2NS/$(n-BuCp)_2ZrCl_2$ showed the highest activity. The activities of supported 2NS-, 1NCy-, 2NIm-functionalized catalysts decreased in the following order, SBA-15/2NS/ > SBA-15/2NIm/ > SBA-15/1NCy/$(n-BuCp)_2ZrCl_2$. 2NS and 2NIm which have two amine groups per silane molecule were shown to interact with $(n-BuCp)_2ZrCl_2$ strongly compared to 1NCy which has one amine group. Thus, the activities increased with an increase in the nitrogen and the Zr content of the supported catalysts.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1183-1186
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• 2007

A shake-flask method was used to determine the n-octanol/water partition coefficients of sulfamethazine, sulfadimethoxine, sulfamethoxydiazine, sulfamonomethoxine, sulfamethoxazole, sulfaquinoxaline and sulfachloropyrazine from (298.15 to 333.15) K. The results showed that the n-octanol/water partition coefficient of each sulfonamide decreased with the increase of temperature. Based on the fluid phase equilibrium theory, the thermodynamic relationship of n-octanol/water partition coefficient depending on the temperature is proposed, and the changes of enthalpy, entropy, and the Gibbs free energy function for sulfonamides partitioning in n-octanol/ water are determined, respectively. Sulfonamides molecules partitioning in n-octanol/water is mainly an enthalpy driving process, during which the order degrees of system increased. The temperature effect coefficient of n-octanol/water partition coefficient is discussed. The results show that its magnitude is the same as that of values in the literature.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.222-227
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• 2009

The seasonal variation of bacterial populations in the Korean cattle (Hanwoo) feedlots dispersed in the 20 cities of Gyeongsangbuk-do, Korea, was monitored for two years (2006 and 2007) to provide quantitative criteria for good agricultural management. Outside the feedlots, the average falling bacterial populations of the air were $3{\pm}1$ CFU/$cm^2\cdot15$ min (n=63) in a year. Inside the feedlots, the average falling bacterial populations of the air were $8{\pm}1$ CFU/$cm^2\cdot15$ min (n=63) in the spring, $16{\pm}2$ CFU/$cm^2\cdot15$ min (n=69) in the summer, $7{\pm}2$ CFU/$cm^2\cdot15$ min (n=69) in the autumn, and $6{\pm}1$ CFU/$cm^2\cdot15$ min (n=70) in the winter. Without using the summer data, the average falling bacterial population of the air was $7{\pm}1$ CFU/$cm^2\cdot15$ min, which was not statistically significant (P=0.37). The average bacterial populations in the cattle drinking water of the cattle feedlots were $4,710{\pm}780$ CFU/ml (n=65) in the spring, $10,430{\pm}1170$ CFU/ml (n=65) in the summer, $4,820{\pm}700$ CFU/ml (n=64) in the autumn, and $2,510{\pm}530$ CFU/ml (n=64) in the winter. Without using the summer data, the average bacterial population of the drinking water was $4,000{\pm}400$ CFU/ml, which was statistically significant (P=0.027). The average frequency of Escherichia coli O157 inside the feedlots was 5% (n=65) in the spring, 72% (n=65) in the summer, 67% (n=66) in the autumn, and 29% (n=66) in the winter on the basis of soil samples of the year 2007. The results indicate that most of the Escherichia coli O157 strains distributed in the summer and autumn was disappeared in the spring through the cold weather of the winter.

• Bulletin of the Korean Chemical Society
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• v.19 no.8
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• pp.847-851
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• 1998

13C, 15N, and 29Si NMR chemical shifts have been computed for selected X-substituted silatranes (X=Cl, F, H, CH3) using Gauge-Including Atomic Orbitals (GIAO) and Continuous Set of Gauge Transformations (CSGT) at the Hartree-Fock level of theory. The isotropic 13C chemical shifts are largely insensitive to substituent-induced structural changes. In this study, the isotropic 13C chemical shifts GIAO and CSGT calculations at the HF/6-31G and HF/6-31G* levels are sufficiently accurate to aid in experimental peak assignments. The isotropic 13C chemical shifts X-substituted silatranes at HF/6-31G* level are approximately 4 ppm different from the experimental values. In contrast, the isotropic 15N and 29Si chemical shifts and the chemical shielding tensors are quite sensitive to substituent-induced structural changes. These trends are consistent with those of the experiment. The 15N chemical shift parameters demonstrate a very clear correlation with Si-N distance, especially when we use the polarization function. Changes in anisotropy, 3a as well as in the 15N isotropic chemical shifts are due primarily to changes in the value of a.. But in case of "Si the correlations are not as clean as for the 15N chemical shift.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.222-231
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• 2020

The egg development and early life history of Sharpbelly Hemiculter leucisculus were investigated. For the experiments, the mature adults were collected at the Lake Yedang in Korea. The eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 0.97±0.02 mm (0.9~1.0 mm n=30) in diameter. The embryo began to hatch about 32 hrs after fertilization under water temperature of 22±1℃. The newly-hatched larvae were 3.0±0.2 mm (2.6~3.4 mm, n=15) in total length, and they haven't Melanophore. Six days after hatching, the Preflexion larva were 5.7±0.1 mm (5.4~5.8 mm, n=15) in total length, and they began to eat a Rotifer. 17 days after hatching, the Flexion larva were 6.8±0.2 mm (6.5~7.0 mm, n=15) in total length, and a gas bladder develop above the intestine. 30 days after hatching, the Postflexion larva were 8.8±0.7 mm (7.9~10.3 mm, n=15) in total length, three dorsal fin rays began to develop in the membrane fins. 50 days after hatching, the Juvenile were 20.8±0.8 mm (18.8~24.6 mm, n=15) in total length, and all their fin-rays were formed.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.109-114
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• 2003

The electronic absorption spectra of trans-$[CrX_2([15]aneN_4)]ClO_4\;([15]aneN_4$=1,4,8,12-tetraazacyclopentadecane; X=F, Cl) complexes have been interpreted using the ligand field theory. An AOMX program is used to optimize the differences between the calculated and the observed positions for the spin-allowed transition bands. The crystal field theory(CFT) parameter is directly related to the angular overlap model(AOM), normalized spherical harmonic hamiltonians(NSH), and semiempirical parameters. The various ligand field parameters are discussed in terms of their chemical significances. According to the ligand field analysis, we can confirm that the fluoride ligand is a very strong ${\sigma}-$ and ${\pi}-$donor while the chloride has weak ${\sigma}-$ and ${\pi}-$donor properties toward chromium(III) ion.

• Elastomers and Composites
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• v.39 no.4
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• pp.318-323
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• 2004

Cloud-point and bubble-point curves for poly(ethylene-co-13.8 mol% octene) ($PEO_{13.8}$) and Poly(ethylene-co-15.3 mol% octene) ($PEO_{15.3}$) were determined up to $150^{\circ}C$ and 450 bar in hydrocarbons which have different molecular size and structure. Whereas ($PEO_{15.3}$+ n-pentane) system has cloud-point and bubble-point type transitions, ($PEO_{15.3}$+ n-propane) and ($PEO_{15.3}$+ n-butane) systems do only cloud-point type transition. In cyclo-pentane, -hexane, -heptane, and -octane, $PEO_{15.3}$ has a bubble-point transition. ($PEO_{13.8}$+ n-butane) mixture has a critical mixture concentration at 5 wt% PEO. (PEO + hydrocarbon) mixtures exhibit LCST type behavior. Solubility of PEO increases with hydrocarbon size due to increasing dispersion interaction which is favorable to dissolve PEO.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.318-324
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• 2016

In order to study the effect of barley, Italian ryegrass (IRG), and legume mixture on nitrogen fixation and transfer to grasses on spring paddy field, an experiment was carried out from Oct. 2006 to June 2007 in Naju, Korea. A split plot design with three replications was used for the experiment. One reference plot was assigned for each treatment to determine nitrogen fixation. Main plots consisted of Chinese milk vetch, crimson clover, forage pea, and hairy vetch with barley, respectively. Subplot treatment were barley or IRG with four seeding ratio of legumes (50:50, 60:40, 70:30, and 80:20). To estimate N fixation by legumes, $^{15}N$ isotope dilution technique was used. $^{15}N$ fertilizer [$(^{15}NH_4)_2SO_4$ solution at 99.8 atom N] was uniformly applied to $600cm^2$ in the middle of each plot on April 15, 2007. Plots were harvest by hand on June 8, 2007. Dried sample were ground to a fine power and analyzed for total N isotope N. $^{15}N$ was determined using elemental analyzer-isotope ratio mass spectrometry. The calculation of N transfer was determined with the isotope dilution method. The content of N was higher in legumes than that in barley or Italian ryegrass. Nitrogen level in forage pea was significantly higher than that of other legumes. There were significantly differences in N content between legumes in IRG mixture. Atom % $^{15}N$ excess was significantly different in legumes with barley. The 60:40 sub plot had higher (p<0.05) atom % $^{15}N$ than other seeding ratio treatments. The enrichment ranged from 0 to 0.58. Compared to barley, the enrichment of IRG with its accompanied legumes was higher, ranging from 0.38 to 1.0. The N derived from the atmosphere (Ndfa) ranged from 0% to 49.5% with barley-legume mixture. It ranged from 0 to 60.5% in IRG-legume plots. N transfer from legumes to neighboring grasses was 12.3 to 90.9 kg/ha for barley-legume mixture and 31.7 to 107.8 kg/ha for IRG plots. IRG plots showed higher N transfer for IRG-legume mixture in general based on difference method. Based on $^{15}N$ dilution method, the N transfer was 0 to 36.1 kg/ha for barley-legume mixture and 0 to 50.6 kg/ha for IRG plots. There was a tendency toward higher N transfer on the difference method than that of the $^{15}N$ dilution method.