• Polymer(Korea)
• /
• v.27 no.6
• /
• pp.542-548
• /
• 2003

Nanoparticles with unsaturated poly(hydroxyalkanoate)s (UPHAs) biosynthesized with Pseudo-monas oleovorans were prepared by spontaneous emulsification solvent diffusion method. The influence of nanoparticle formation was investigated with various experimental parameters such as sonication conditions, sol-vent, surfactant and polymer contents, etc. The physical and chemical properties of UPHAS and its nanoparticles were characterized using $^1$H- and $\^$13/C-nuclear magnetic resonance spectroscopies, attenuated total reflection infrared spectroscopy, differential scanning calorimetry and gel permeation chromatography. The morphology of particles was observed using scanning electron microscope and the size and distribution of nanoparticles were measured with electrophoretic light scattering spectrophotometer. The mean diameter of particles decreased with increasing sonication amplitude and time. The addition of ethanol into UPHAS chloroform solution decreased the particle size presumably due to increased solvent diffusion into water phase. The particle size increased with increased the concentration of UPHAS solution. Under the 2-4％ poly(vinyl alcohol) (PVA) aqueous solution the minimum mean diameter of particles was shown. The higher degree of hydrolysis and degree of polymerization of PVA increased the mean diameter of particles.

• Korean Journal of Food Science and Technology
• /
• v.24 no.6
• /
• pp.519-523
• /
• 1992

The patterns on the proteolysis of mussel protein using a commercial enzyme preparation were investigated. The best one among six commercial enzyme preparations for the manufacture of mussel extract was Corolase PP, based on the degree of hydrolysis (DH). When the raw mussel paste, without water addition, was adjusted to pH 6.5, added 0.1% (w/w dry basis) of Corolase PP. and reacted at $50^{\circ}C$ for four hours, it reached the maximum value of DH (79%). The precooking of raw mussel decreased the efficiency of extraction and hydrolysis of the protein, due to the inactivation of the autolytic enzymes contained in the mussel. During the course of proteolysis, major free amino acids such as glycine, alanine, glutamic acid and lysine, representing a characteristic brothy taste of mussel were replaced with free hydrophobic amino acids including valine, methionine, isoleucine, and leucine. The electrophoretic pattern and HPLC-GPC pattern of mussel protein hydrolysates during the hydrolysis were observed and also discussed.

• Korean Journal of Weed Science
• /
• v.10 no.4
• /
• pp.269-276
• /
• 1990

Weed species belonging to the broadleaf family prevailed in the experimental sites followed by Cyperucea and grass family. In terms of life cycle, the dominant weed species were the perennial weeds rather than annual weeds. Most of weeds were emerged between 30-60days after transplanting in Chuncheon and between 40-60 days after transplanting in Hongcheon and Hoengseong areas. Among agronomic characteristics of rice affected by weed emergence were decrease of plant height by 2-4㎝, panicle number by 1.3-2.9, spkelet by 3. 7-7.5, ripening rates by 3.3-6.5%, and milled yield by 12-17%.

• Korean Journal of Weed Science
• /
• v.10 no.2
• /
• pp.83-92
• /
• 1990

Experiment was conducted to establish the weed control system on the paddy fields by investigating species, period and amount of weeds in Gangwon province. Four locations were selected for these experiments : West plain area, Chunchon(74m above the sea level), mid-mountainous area, Hongchon(300 m), high alpine area, Hoengsong(450m), and east sea area, Myungju(14m). Weed emergence was investigated 6 times from 10 days after transplanting to 60 days with 10 days interval. From the experiments stated above, the results were summarized as follows ; The identity of weed species was small in grass family, but broad-leaf family was numerous. Also the dominant weed species was generally the perenial weeds. The weed emergence was initiated from 10 days after translanting. The amounts of weed counted the most in Chunchon. A large number of weeds were emerged between 30-60 days after transplanting in Chunchon and between 40-60 days after transplanting in Hongchon and Hoengsong. Among agronomic characteristics affected by weed emergence during rice development, plant height was decreased by 2~4cm, panicle number by 1.3~2.9, spikelet by 3.7~7.5, ripening rates 3.3~6.5%, and milled yield by 12~17%, respectively.

• Tuberculosis and Respiratory Diseases
• /
• v.40 no.6
• /
• pp.653-658
• /
• 1993

Background: Recent advancement of molecular genetics has revealed that malignant transformation of a cell may be a complex multistep process and this process is grouped, in general, into two distinct categories, activation of protooncogenes and inactivation of tumor suppressor genes. This study was focused on the mutation of p53 tumor suppressor gene, because p53 gene mutation is now generally accepted to be one of the most frequent genetic changes in a variety of human cancers. Although lung cancer is one of the common cancers in Korea, the genetic change in the carcinogenesis process is not yet known clearly. To investigate the role of p53 gene mutation in lung cancer, we examined the mutations of exon 4-8 of the p53 gene in humna lung cancer cell lines, because most of the mutations of p53 gene have been reported to develop in exon 4-8. Method: Genomic DNA was obtained by the digestion of proteinase K and the extraction by phenol-chloroform-ethanol method from two human pulmonary adenocarcinoma cell lines, PC-9 and PC-14, and one human small cell lung cancer cell line, H69. To detect the mutations of exon 4-8 of the p53 gene, polymerase chain reaction single-strand conformation polymorphism(PCR-SSCP) analysis was performed with the DNA extracted from the cells. Results: The mutation of p53 gene was present in all three cell lines tested. In PC-9, PC-14 and H69, the altered mobility was detected in exon 7, 7 and 5, respectively. Conclusion: These results suggest that p53 gene mutation plays an important role in certain steps of the carcinogenesis of human non-small cell and small cell lung cancer.

• The Korean Journal of Petroleum Geology
• /
• v.2 no.2 s.3
• /
• pp.51-57
• /
• 1994

Analysis of the aeromagnetic data aquired by US Navy in the year 1969 permits us to predict a new sedimentary basin, Heugsan Basin, south of the known Gunsan Basin in Block Ⅱ. The basin appears to consist of three sub-basins trending NNW-SSE. The results of our analysis provide not only an independent assessment of the Gunsan Basin, but also new important information on the tectonic origin and mechanism for the two basins as well as for the entire region. The basin forming tectonic style is interpreted as rhombochasm associated with double overstepped left-lateral wrench faults. From the magnetic evidence, a few NE-SW trending major onshore faults are extended to the study area. We also interpreted the nature of the faults to be left-lateral wrenches. This new gross structural style is consistent with the results of recent Yeongdong Basin analysis by Lee. The senses of fault movement are also supported by the paleomagnetic evidence that the Philippine Sea had experienced an 80-degree clockwise rotation since the Eocene. Based on a 2 $\frac{1}{2}$ model study the probable maximum thickness of the sediments in the Gunsan Basin is approximately 7500 meters. We believe that the new Heugsan Basin was left unidentified because a high velocity layer may be overlying the basin. Because the overall structural configuration of the Heugsan Basin appears to be favorable for hydrocarbon accumulation, a detailed airborne magnetic survey is recommended in the area in order to verify the magnetic expression of this thick basin. A detailed subsequent marine gravity survey is also recommended in order to delineate the sedimentary section and to acquire supplemental data to the magnetic method only if an overlying high velocity layer is confirmed. Otherwise a high energy source seismic survey may be more effective.