• Natural Product Sciences
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• v.12 no.4
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• pp.241-246
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• 2006

Alstonia scholaris is known as 'Saptaparna' in Ayurvedic System of Medicines and the bark is used for the treatment of various diseases. It has various ethnomedicinal values as different traditional communities find diverse medicinal properties. The present communication deals with the seasonal variation studies of the stem bark of this plant. The bark was collected in the month of January, July and November. There is no macro-microscopical changes in all the three seasons but the ash values showed significant differences. Crude fibre content showed sharp decline from January to July to November. Total tannin percentage was found maximum in January and minimum in June. TLC finger print profile showed more concentration of constituents in January as compared to June and November. Hence, the bark may show more efficacy when collected in January.

• Structural Engineering and Mechanics
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• v.35 no.3
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• pp.365-377
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• 2010

In the present article, effect of non-uniform excitation due to spatially variation of seismic input on nonlinear response of concrete gravity dams is considered. The reservoir is assumed compressible. Isotropic damage mechanics approach is used to model static and dynamic nonlinear behavior of mass concrete in 2D space. The validity of utilized nonlinear model is considered using available theoretical results under static and dynamic conditions. The tallest monolith of Pine Flat dam is selected as a case study. Two cases are analyzed for considering the effect of limited wave propagation velocity on seismic behavior of the dam-reservoir system in which travelling velocities are chosen as 2000 m/s and infinity. It is found that tensile damage in neck and toe regions and also, in the vicinity of the base increase when the system is excited non-uniformly.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.178-182
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• 2006

This study was conducted to investigate the variation in sequence, the base composition and the sequence similarity of 18S rDNA (18S ribosomal RNA coding region) in the 10 Polygonatum spp. collections. The entire 18S rDNA region of 10 Polygonatum spp. collections ranged from 913 bp to 914 bp. There were 8 variable sites in the entire 18S region, and they were attributable to nucleotide substitution and deletion. $T{\rightarrow}C$ transition happened in 4 sites, and $A{\rightarrow}G$ transition happened in 1 site. $C{\rightarrow}A$ transversion happened in 1 site, and deletion happened in 2 sites. Transition rates were five times that of transversion. Base compositions of 18S rDNA were $23.09{\sim}23.33%$ in adenine, $23.33{\sim}23.52%$ in guanine, $25.60{\sim}25.85%$ in thymine and $27.38{\sim}27.79%$ in cytosine. The A + T content of 18S rDNA of 10 Polygonatum spp. collections averages 48.99%, ranging from 48.80% to 49.18%, and the G + C content averages 51.01%, ranging from 50.82% to 51.20%. Pairwise sequence comparisons indicated that 18S rDNA sequence similarity ranged from 99.7% to 100%.

• Journal of Life Science
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• v.21 no.6
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• pp.788-795
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• 2011

Accurate identification for pathogenic bacterium is an essential element in the clinical microbiology laboratory. We studied molecular analysis involving the identification of Chyseobacterium indologenes and evaluated the seventeen isolates in Korea with the 16S rRNA gene of the ribosome to estimate phylogenetic relationships within the genus Chyseobacterium in GenBank. The aligned data sets for C. indologenes were 1,176 nucleotides. Sequence variation within the C. indologenes was mostly due to nucleotide substitutions. Korean C. indologenes isolates were not strikingly different from the same species found in the other countries. However, the rates of base substitution in Korean C. indologenes isolates were higher than those of other C. indologenes isolates in GenBank. C. indologenes was placed as a sister species to C. isbiliense, C. hominis, C. hispanicum, C. molle, C. hungaricum, and C. pallidum.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.61-66
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• 2008

It is important to calculate the exact crack opening area in the cracked pipe subjected to axial force and bending moment. Among many solutions for obtaining the crack opening displacement, Paris-Tada's expression, which is derived from energy method, is open used in fracture analysis for piping crack problems because of its simplicity. But Paris-Tada's equation has conservativeness when radius over thickness ratio(R/t) is ten or less, for it is based on the stress intensity factor solution having a compliance function derived from a simple shell theory. In this paper we derived a new expression using a different stress intensity factor solution which is able to consider the variation of compliance through wall thickness in a cracked pipe. Conservativeness of both equations was examined and compared to finite element analysis results. Conservativeness of the new equation is decreased when R/t > 10 and increased slightly when R/t < 10 compared with Paris-Tada's. But Both equations were highly conservative when R/t < 10 compared with finite element analysis results.

• The Korean Journal of Malacology
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• v.21 no.2 s.34
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• pp.147-161
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• 2005

To elucidate the phylogenetic relation of the superfamily Veneroidea, we obtained partial 28S rRNA sequences of 14 heterodonts and three pteriomorphs which were collected from Korea and the sequence data of related taxa from GenBank, and analyzed maximum parsimony with PAUP program 750 of the nucleotide positions were variable, 560 of which were informative under conditions of parsimony. Total tree length was 2,765, and consistency index, homoplasy index (HI), and Retention index was 0.4843, 0.5157, and 0.6291, respectively. Intraspecific variation of 28 rRNA of Corbicula fluminea and Sinonovacula constricta was 3.1% and 1.3%, respectively. Pitarinae-Cyclininae-Meretrinae group had a clade and Samaranginae, Chioninae, and Dorsininae were clustered.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.356-361
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• 2007

Recently, the development of various culture-independent identification techniques for environmental microbes has greatly enhanced our knowledge of microbial diversity. In particular, denaturing gradient gel electrophoresis (DGGE) of 16S rDNA fragments, generated using the polymerase chain reaction (PCR) is frequently used to examine the diversity of environmental bacterial populations. This method consists of direct extraction of the environmental DNA, amplification of the 200-600 bp 16S rDNA fragments with universal primers, and separation of the fragments according to their melting point on a denaturing gradient gel. In this study, we investigated the seaside microbial community in coastal areas of Busan, Korea, using culture-independent techniques. First, marine genomic DNA was extracted from seawater samples collected at Songjeong, Gwangahn, and Songdo Beaches. Then, PCR was used to amplify the bacterial 16S rDNA using universal primers, and DGGE was used to separate the amplified 500 bp 16S rDNA fragments. Finally, the tested 16S rDNA genes were further analyzed by sequencing. Based on these experiments, we found that DGGE analysis clearly showed variation among the regional groups. It can be used to monitor rapid changes in the bacterial diversity of various environments. In addition, the sequence analysis indicated the existence of many unculturable bacteria, in addition to Arcobacter, Pseudoaltermonas, and Vibrio species.

• Animal Systematics, Evolution and Diversity
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• no.nspc3
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• pp.139-146
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• 1992

The primary sequence of the 18S rRNA gene of a crustacean Pugettia quadridens (Decapoda: Pleocyemata: Brachyura) was determined by the PCR cloning and Taq sequencing. The 18S rRNA gene of this species in 1837 bases long, and 46 bases shorter than that of another crustacean decapod Oedignathus inermis. The similarity between two species is 90.8% when the insertion and/or deletion sites were excluded. Within the molecule, the most conservative (identical) region locates at the position of 1137-1206 and it is 70 bases long. The most long consecutive nucleotide differences occur at the position between 46-55 and the second most between 399-407. The sequence variation in the primary structure of 18S rRNA gene are not evenly distributed throughout the molecule.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.6
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• pp.725-734
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• 1997

The effect of helical intake port geometry on in-cylinder swirl flow characteristics was studied. Two helical intake ports were selected to change swirl ratio, mean flow coefficient with the variation of valve lifts, valve eccentricity ratios and axial distance. The measurements were made by using an impulse swirl meter. The port B modified to increase the swirl ratio( $R_{s}$) had the tendency of the increased non-dimensional rig swirl ( $N_{r}$) distribution in comparison with that of the port A. And the $N_{r}$ distribution was remarkably improved at low valve lifts. The modification of the geometry to increase the swirl ratio ( $R_{s}$) in helical intake port resulted in the decrease of the mean flow coefficient ( $C_{f(mean)}$) regardless of valve eccentricity ratio ( $N_{y}$). And also non-dimensional rig swirl ( $N_{r}$) in the high valve lift affected the calculation of swirl ratio considerably.onsiderably.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.51-55
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• 1999

Cosmetic mask is one of the traditional cosmetic product and is used to keep skin healthy and beautiful through moisturizing effect, cleansing effect and acceleration effect on microcirculation. There are several types of cosmetic mask such as peel-off type, tissue-off type, wash-off type and cotton sheet type immersed in cosmetic water. It is important for cosmetic formulators to develop an adequate type of cosmetic mask that meets the needs of the target consumers because each type of cosmetic mask has benefits and problems in its usage and efficacy. Polyvinyl alcohol (PVA) is widely used as an active ingredient of peel-off type cosmetic mask and the physical property of the PVA film changes with the usage of other ingredients. We studied the change of physical properties of the film containing PVA by formulating peel-off type cosmetic mask with the variation of humectants. Methylguceth-20 and glycereth-26 reduce the interaction between skin surface and PVA film without serious weakening of tensile strength and they can alleviate irritation. Glycerin, urea and betaine help PVA film soften and they also have excellent efficacy as humectants.