• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.285-291
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• 2012

Purpose: This study was conducted to identify the surface characteristics of titanium discs coated with MS275/PLGA by electrospray and which is effective to mesenchymal stem cell proliferation. Materials and methods: We used anodized surface coated with PLGA as a control group and anodized surface coated with MS275 $0.5{\mu}M$, $1{\mu}M$, $1.5{\mu}M$ as test groups. To examine that the coating particles are nanometer sized, FE-SEM was used and AFM was utilized to determine the difference of coating surface roughness. We checked the mesenchymal stem cell proliferation by using MTT assay on $1^{st}$, $4^{th}$, $7^{th}$ days. Results: There was no significant difference between control groups and test groups in AFM results (P>.05). In MTT assay results, mesenchymal stem cell proliferation was increased with time, at $7^{th}$ day, cell viability on discs coated with $1.5{\mu}M$ MS275 was significantly higher than control group (P<.05). As SEM showed, the number of cells on all discs was increased and the morphology of cell attachment was also wider and closer with time. Conclusion: Titanium surface coated with MS275/PLGA showed significantly higher cell proliferation and the more density of MS275 was dispersed on titanium discs, the faster cells grew.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1157-1163
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• 2011

This study was conducted to investigate the cause of microbiological contaminants in aseptic chocolate milk and evaluate the effect of a physicochemical treatment on the growth inhibition of isolated bacterial strains. The bacterium isolated from aseptic chocolate milk was identified as Bacillus lentus and was named B. lentus M1. In the heat and pH treatment, the growth of B. lentus was inhibited at 110$^{\circ}C$ for >15 min and at pH's <5 and >10. An electrolyzed water treatment against B. lentus M1, revealed 5 mm growth past the inhibition zone. The effect of ozone gas on B. lentus M1 growth was evaluated using viable cell counts. When the initial number of B. lentus M1 was $10^2$ and $10^3$ CFU, the bacteria were completely suppressed by ozone gas treatment for 10 and 30 min, respectively. In a microwave treatment, B. lentus M1 was sterilized following microwave treatment for 1 min. As the result of ${\gamma}$-irradiation against B. lentus M1, numbers decreased as the ${\gamma}$-irradiation dosage increased. These results show the growth inhibition effects against contaminants in aseptic chocolate milk using physicochemical treatments.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.541-550
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• 2010

A new $N_4O_3$ heptadentate ligand, N,N'-Bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol(H-BAP 4HCl)was synthesized. The hydrochloric acid salts of Br-BAP 4HCl, Cl-BAP 4HCl, $CH_3O$-BAP 4HCl and $CH_3$-BAP 4HCl containing Br-, Cl-, H-, $CH_3O-$ and $CH_{3^-}$ groups at the para-site of the phenol group of the H-BAP were synthesized. The structures of the ligands were confirmed by C. H. N. atomic analysis and $^1H$ NMR, $^{13}C$ NMR, UV-visible and mass spectra. The elemental stepwise protonation constants(${logK_n}^H$) of the synthesized $N_4O_3$ ligands showed six steps of the proton dissociation. The orders of the overall dissociation constants($log{\beta}_p$) of the ligands were Br-BAP < Cl-BAP < H-BAP < $CH_3O$-BAP < $CH_3$-BAP. The orders agreed well with that of Hammett substituent constants($\sigma_p$). The calculated stability constants($logK_{ML}$) between the ligands and transition metal ions agreed well with the order of the overall proton dissociation constants of the ligands but they showed a reverse order in Hammestt substituent constants($\sigma_p$). The order of the stability constants between the transition metal ions with the ligands were Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II).

• The Journal of the Petrological Society of Korea
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• v.20 no.3
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• pp.161-172
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• 2011

Open beaker digestion method is routinely used as the sample preparation technique for trace element determination of rock samples by inductively coupled plasma mass spectrometry, With this method, however, dissolution of Zr and Hf is not always guaranteed especially when the samples contain refractory minerals. In this study, glass bead digestion technique was compared with conventional open beaker digestion technique for the sample preparation of three USGS rock standards such as AGV-2, BHVO-2, and G-3. Thirty trace elements including rare earth elements were analysed by ICP-MS and ICP-AES. There were no clear differences in analytical results for the AGV-2 and BHVO-2 standards between the two techniques, but Zr, Hf, Y, and middle- to heavy- rare earth element concentrations of the G-3 standard prepared by open beaker digestion technique were significantly lower than the recommended values. This can be attributed to the presence of refractory mineral zircon. On the contrary, all the analytical results of the G-3 standard prepared by glass bead digestion technique were in good agreement with the recommended values, indicating complete dissolution of zircon. The analytical results show that the volatile elements such as Pb and Zn were not lost during the preparation of glass bead. Low dilution glass bead digestion technique described here will be very helpful to enhance precision and accuracy of trace element analysis for geological samples containing refractory minerals.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.60-67
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• 2010

Although several studies have reported that Cr, Cu and As can leach from CCA-treated woods, few studies have been conducted on this topic in Korea. Therefore, this study was conducted to monitor Cr, Cu and As leaching from CCA-treated wood products and to develop a rapid identification method for CCA-treated wood products by using indicators such as PAN stain. Soil samples were collected at depths of 0-70 cm and wood samples were collected by thickness of wood layer. The soil and wood samples were then digested and analyzed for Cr, Cu and As concentrations using an atomic absorption spectrometer. The As and Cu concentrations decreased sharply with depth from 34.38 and 33.65 mg $kg^{-1}$ at 0-1 cm to 1.72 and 7.84 mg $kg^{-1}$ at 70 cm, respectively. In general, As was more mobile than Cr and Cu in the soil. For wood samples, the Cr, Cu and As concentrations were higher in the outer layer (0-0.5cm) than the inner layers (0.6-4.5cm). Evaluation of rapid identification methods revealed that 100% acetone with 0.1% PAN indicator was the best combination for detection of CCA-treated wood in the field.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.207-216
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• 2020

Purpose: To compare the polishing characteristics and their influence on Candida albicans adhesion to the recently introduced polyetherketoneketone (PEKK) and the conventional polymethylmethacrylate (PMMA) denture resin material. Materials and methods: Specimens from PEKK (Group E) and PMMA (Group M) were made in dimensions of 8 mm in diameter and 2 mm in thickness. The specimens were further divided into sub-groups according to the extent of polishing (ER, MR: rough; EP, MP: polished, N = 12 each). The specimens were polished using polishing machine and SiC foil. ER and MR group specimens were polished with 600 grit SiC foil only. EP and MP groups were further polished with 800, 1,000, 1,200 grit SiC foils sequentially. To measure the surface roughness values (Sa) of specimens, atomic force microscope (AFM) was used and scanning electron microscope (SEM) observation under 1,000, and 20,000 magnifications was performed to investigate surface topography. The polished specimens were soaked in C. albicans suspension for 2 hours with shaking to promote adhesion. The attached C. albicans were detached from the surface with 10 times of pipetting. The suspension of detached C. albicans was performed by serial dilution to 10³ times, and the diluted suspensions were inoculated on Sabouraud dextrose agar plates using spread plate method. After incubating the plate for 48 hours, colony forming unit (CFU)/plate of C. albicans was counted. Statistical analysis was performed using one-way ANOVA and Tukey HSD test to confirm significant difference between the groups (α=.05). Results: Average Sa value was significantly higher in MR group compared to other groups (P<.05), meaning that additional polishing steps reduced surface roughness effectively only in the PMMA specimens. There was no significant difference in Sa values between MP and EP groups. In SEM images, PEKK specimens showed numerous spikes of abraded material protruding from the surface and this phenomenon was more significant in EP group. The mean CFU/plate value was the highest in EP group and this was significant when it was compared to MP group (P<.05) which was the lowest. Conclusion: Polishing PEKK using serial SiC abrasive foil may result in higher adhesion of C. albicans. In clinic, this should be considered carefully.

• Journal of the Korean Magnetics Society
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• v.18 no.6
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• pp.211-216
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• 2008

The effects of Si impurity on electronic structures and magnetism of bcc Fe are investigated by using a first-principles method by considering spin-orbit coupling. In order to describe the Si impurity, a 27 atomic bcc Fe supercell has been considered. The Kohn-Sham equation was solved in terms of the all-electron full-potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation (GGA). The effects of spin-orbit coupling were calculated self-consistently by considering spin-diagonal terms based on second variation method. For the ferromagnetic (FM) state without considering SOC, the spin magnetic moment of the Si impurity was calculated to be $-0.143{\mu}B$, while the magnetic moments of Fe atoms were calculated to be $2.214{\mu}B$, $2.327{\mu}B$, and $2.354{\mu}B$ in away from the Si atom, respectively. However, the FM state with considering SOC, the spin magnetic moment of the Si impurity was calculated to be $-0.144{\mu}B$, which is not affected significantly by SOC, but the spin magnetic moments of Fe atoms were calculated $2.189{\mu}B$, $2.310{\mu}B$, and $2.325{\mu}B$, respectively, which are much reduced value compared to those of the FM state without SOC. Comparing the total charge density and spin density, those features are thought to be originated by the screening distortions of the Fe $t_{2g}$ orbital, which can be obtained by considering SOC.

• The Korean Journal of Zoology
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• v.9 no.2
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• pp.12-20
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• 1966

Studies on the rate of growth, the rate of feeding and the efficiency of food conversion on the stage of new-born fries to the near adult size for three species of cuttlefishes , Sepia esculenta, Sepia subaculeata, Sepiella maindroni and two species of squids, Sepioteuthis lessomiana, Euprymna berryi were carried out in the process of artificial raising, and then argued about a feasibility of the propagation of cuttlefishes and squids. 1. The relation between the daily age (D) and the body weight(W) of Sepia exculent is expressed in a logarithmic equation, log W=3.0649 log D-4.2768. The daily rates of growth through 121 days of the raising period were 1.46 per cent for the man시 length and 1.67 percent for the body weight. The raipidest growth of Sepia esculenta is observed at the stage of 1 to 4 cm in the mantle length . At that time the daily rates of growth reach 3.3 to 5.5 percent for the mantle length and 10.4 to 12.0 percent for the body weight, respectively. The growth of Sepia esculenta varies a great deal to the bait. When fed on a dead bait the rates of growth decrease 17 per cent for the mantle length and 26 percent for the body weight compared with those fed on a live bait. 2. The relation between the daily age and the body weight of Sepia subaculeata is expressed in a logarithmic equation, log W=3.7447 log D-4.9003. The daily rates of growth through 110 days of the raising period were 1.63 percent for the mantle length and 1.83 percent for the body weight. The rapidest growth of Selia subaculeata is observed at the stage of 1.5 to 9.0 cm in the mantle length. At that time the daily rates of growth reach 3.1 to 7.4 percent for the mantle length and 6.8 to 16.7 percent for the body weight , respectively. 3. The relation between tehdaily age and the body weight of Sepiella maindroni is expressed in a ogarithmic equation , log W=2.9332 log D-3.8224 . The daily rates of growth through 133 days of the rearing period were 1.39 percent for the mantle length and 1.51 percent for the body weight . The rapidest growth of Sepiella maindroni is observed at the stage of 0.4 to 5.8 cm in the mantle length. At that time the daily rates for growth reach 4.6 to 7.3 percent for the mantle length and 8.5 to 15.4 percent for the body weight , respectively. 4. The daily rates of growth onthe stage of 0.5 to 6.0 comin the mantle length of Sepioteuthis lessoniana were 4.1 to 5.9 percent for the mantle length and 7.1 to 10.7 percent for the body weight . 5. During the rearing period of 31 days immediately after the hatching , the daily rateof feeding of Sepia esculenta marked 11.0 to 39.4 percent (28.2 percent in an average), and the efficiency of food conversion of this species reached 9.0 to 71.0percent (38.7percent in an average). Even at the more growing stage of 4.5to 6.2 cm in the mantle length, the daily rate of feeding of three species of cuttlefishes wee maintained 17.7 percent for Sepia esculenta, 30.8 percent for Sepia subaculeata and 34.7percent for Sepiella maindroni on an average. 6. The efficiency of food coversion of cuttlefishes and squids are larger than those of other fishes, and all the species are rapid in their growth. Four to five months are thought to be enough for their growing into a fair commercial size.

• Journal of Life Science
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• v.24 no.6
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• pp.618-625
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• 2014

Rice flour is used in many food products. However, dough made from rice lacks extensibility and elasticity, making it less suitable than wheat for many food products such as bread and noodles. The high-molecular weight glutenin subunits (HMW-GS) of wheat play a crucial role in determining the processing properties of the wheat grain. This paper describes the development of marker-free transgenic rice plants expressing a wheat Glu-Dy10 gene encoding the HMG-GS from the Korean wheat cultivar 'Jokyeong' using Agrobacterium-mediated co-transformation. Two expression cassettes, consisting of separate DNA fragments containing Glu-1Dy10 and hygromycin phosphotransferase II (HPTII) resistance genes, were introduced separately into Agrobacterium tumefaciens EHA105 for co-infection. Each EHA105 strain harboring Glu-1Dy10 or HPTII was infected into rice calli at a 3: 1 ratio of Glu-1Bx7 and HPTII. Among 290 hygromycin-resistant $T_0$ plants, we obtained 29 transgenic lines with both the Glu-1Dy10 and HPTII genes inserted into the rice genome. We reconfirmed the integration of the Glu-1Dy10 gene into the rice genome by Southern blot analysis. Transcripts and proteins of the Glu-1Dy10 in transgenic rice seeds were examined by semi-quantitative RT-PCR and Western blot analysis. The marker-free plants containing only the Glu-1Dy10 gene were successfully screened in the $T_1$ generation.

• Journal of Preventive Medicine and Public Health
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• v.21 no.2 s.24
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• pp.307-319
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• 1988

In order to determine the contents of lead, cadmium and zinc, the tissues of the crussian carp, Carassius carassius, collected from the middle streams of the Nakdong river were examined. During the dry season from 8 to 15, March, 1987, six loci were selected to sample the fish and river water; five of them were the midstreams of the Nakdong river i. e., the vicinities of the Andong dam, the Nakdong bridge, the Waegwan bridge, Gangjung and Gaepori, the other one was the Kumho river around the Paldal bridge(see Fig. 1). The microanalyses of lead and cadmium contents were undertaken by the atomic absorption spectrophotometer(Model IL-551) connected with CTF-IL 655, while that of Zinc by the flame method with IL551 only. The contents of lead and cadmium in water sampled from Gaepori distant from about 30km downward from the junction with the Kumho river were about 1.5 times higher than those from Gangjung distant about 0.5km upward from the junction, and the content of zinc from Gaepori was slightly higher than that from Gangjung. However, the contents of lead and cadmium in water sampled from Gaepori were three fifth of those from the vicinity of Paldal bridge far about 2km upperward from the junction. In the other words, the contents of lead and cadmium in the samples from the vicinity of the Paldal bridge were about 2.5 to 3 times higher than those from the Gangjung and 5 times higher than those from the Andong dam. The contents of the heavy metals in the tissues of Carassius carassius were relatively consistent to those of the aquatic environments where the fish were collected, with higher contents in the tissues of the crussian carp collected from the vicinity of Gaepori and the Paldal bridge which were so much polluted than in those from other loci in upper stream from the junction. And the contents of lead and cadmium in tissues were positively correlated with the age of the fish, however, that of zinc was not. The contents of lead in bone of crussian carp from the vicinity of the Paldal bridge in the group of 0-1 year old fish were similar to those of 4-5 years old fish from Gaepori, and higher than those of 3-4 years old fish collected from the upper stream of the junction. It is likely that fishing from Gaepori and the paldal bridge is not recommended, and all the industrial producers have to pay intensive attention to the water pollution due to the sewage disposal.