• Wind and Structures
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• v.29 no.6
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• pp.457-469
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• 2019

In this paper, a numerical solution is presented for supersonic flutter analysis of cantilever non-symmetric functionally graded (FG) sandwich plates. The plate is considered to be composed of two different functionally graded face sheets and an isotropic homogeneous core made of ceramic. Based on the first order shear deformation theory (FSDT) and linear piston theory, the set of governing equations and boundary conditions are derived. Dimensionless form of the governing equations and boundary conditions are derived and solved numerically using generalized differential quadrature method (GDQM) and critical velocity and flutter frequencies are calculated. For various values of the yaw angle, effect of different parameters like aspect ratio, thickness of the plate, power law indices and thickness of the core on the flutter boundaries are investigated. Numerical examples show that wings and tail fins with larger length and shorter width are more stable in supersonic flights. It is concluded for FG sandwich plates made of Al-Al₂O₃ that increase in volume fraction of ceramic (Al₂O₃) increases aeroelastic stability of the plate. Presented study confirms that improvement of aeroelastic behavior and weight of wings and tail fins of aircrafts are not consistent items. It is shown that value of the critical yaw angle depends on aspect ratio of the plate and other parameters including thickness and variation of properties have no considerable effect on it. Results of this paper can be used in design and analysis of wing and tail fin of supersonic airplanes.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1996.12a
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• pp.61-61
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• 1996

Taxol is used as cancer therapeutic agent. It has been known as weak posotive of chromosome aberration assay in vitro in our previous results (Ryu et al., 1996) and potent clastogens in the mouse bone marrow micronucleus (Tinwell and Ashby, 1994). We performed microgel electrophoresis to determine the effect of taxol and it's precursor 10-deacetyl baccatin III(DAB) on DNA. Microgel electrophoresis is useful, rapid, simple, visual, and sensitive technique for measuring DNA breakage and repair mechanisms in mammalian 근ells. The range of concentration used for taxol were 854, 427, 213.5, 106.8, 53.4 Ug/ml, for DAB 910 ,455, 227.5 U9/ml, Cell viability always exceed 85%. We analyzed the results by using the special software of image analyzer for this comet assay (Komet 3.0). By using this image analyzer software , we can get the result as the tail moment ((mean of tail length - mean of head lengh) x tail%DNA/100). A slight increase in DNA migration was observed for taxol at the concentration of 854 Ug/m4 in the absence of S9 mixture. No increased DNA migration was observed after treatment with DAB.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.145-151
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• 2006

The molecular assembly of p-iodo-phenyl octadecyl ether (I-POE), p-iodo-phenyl docosyl ether (I-PDE) and a binary mixture of these two molecules on graphite has been studied using a scanning tunneling microscope. Each molecular system self-assembles on the graphite surface to form a stable monolayer with a head-to-tail configuration. For the binary system, the I-POE and I-PDE molecules do not mix on the surface, preferring instead to form isolated monolayer domains. Here, the I-POE molecules are preferentially adsorbed on the graphite surface, due to the effects of alkyl chain length and the functional group on the monolayer structure.

• Toxicological Research
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• v.23 no.1
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• pp.25-31
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• 2007

To evaluate the protective effect of Houttuynia cordata on hydrogen peroxide-induced oxidative DNA damage in HepG2 cell line, we used an alkaline single-cell gel electrophoresis (SCGE; comet assay). The DNA damage was analyzed by tail moment (TM) and tail length (TL), which used markers of DNA strand breaks in SCGE. The $100{\mu}g/ml$ of methanolic extract of Houttuynia cordata root showed significant protective effects (p < 0.01) against hydrogen peroxide-induced DNA damage in HepG2 cells and increased cell viability against hydrogen peroxide. The results of this study indicate that Houttuynia cordata root methanol extract acts as a potential antioxidant, and exhibits potential anticancer properties, which may provide a clue to find applications in new pharmaceuticals for oxidative stability.

• Journal of Species Research
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• v.5 no.3
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• pp.318-323
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• 2016

Acrobeles ciliatus (von Linstow, 1877) and Plectus parietinus (Bastian, 1865) are newly collected from Korea. Acrobeles is similar to those nematode belongs to Rhabditidae and Panagrolaimidae by having terminal bulb without medium bulb but different by having complex, vines shaped labial attachment. A. ciliatus differed from other Acrobeles species by lateral fields with two incisures, primary axils U-shaped, and secondary axils V-shaped. Head region set off with the neck, three high labial probolae present, each having 5 tines at inner margins and 5-7 at outer margins, and two elongate apical tines. Also, it differs from the longer female body. Plectus parietinus is distinguished from all other species of Plectus by the prominent hypodermal glands, the relatively small amphid, the distinct and well set-off lips and by the subdorsal distal caudal seta on the left side of the tail. Stoma without stylet. Oesophagus about 1/4 of total body length with terminal bulb. Anus ca. $100{\mu}m$ from posterior extremity. Vulva is at middle of body. Have spinneret on tail tip.

• The Journal of Pediatrics of Korean Medicine
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• v.19 no.1
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• pp.67-82
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• 2005

Objectives : This study was conducted to find out the effect of Yukmijiwhangtanggamibang (YM) on growth, learning and memory of rats. Methods : It was divided SD rats into Sham group, 192 Saporin injection(SA+Saline) group and Injection of 192 Saporin with YM(SA+YM) group. Growth measure length of bone and tail. Memory performance was used aquisition test and learning retention of morris water maze. It was detected acetylcholinesterase(AChE), cholineacetyltransferase(ChAT) at medial septum and hippocampus by immunohistochemistry Results : Body Weight of the SA+YM Group increased effectively, as compared with SA Saline group. Growth of bone in the SA+YM Group increased effectively, as compared with SA+Saline group. Growth of Tail in the SA+YM Group increased effectively, as compared with SA_Saline group. The SA+YM Group in Aquisition Test improved effectively, as compared with SA+Saline group. The SA+YM Group in Learning Test improved effectively, as compared with SA+Saline group. The numbers of ChAT cells in Medial septum increased effectively, as compared with SA+Saline group. The numbers of ChAT cells in CA1 of Hippocampus increased, but was not effective. Conclusion : These results suggest that YM has an improving effect on the impaired learning through the effects on memory registration and retrieval.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.101-107
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• 2004

To ascertain the effects of hair dyeing application on the DNA damage in human lymphocytes, a mixture of permanent black colored hair dye with the same amount of oxidant containing 6% hydrogen peroxide was used. A hair dyeing with contacting the scalp (conventional dyeing) and a hair dyeing with 3 to 4mm away from the scalp (alternative dyeing) were applied to each If young healthy women. Blood was taken from the brachial vein at two sampling times, just before and 6 hours after the hair dyeing, and tail extent moment(TEM) and tail length (TL) were measured by using a comet assay. After dyeing, TL was significantly increased in both conventional dyeing group and alternative dyeing group compared with before dyeing as an average of 47% and 28%, respectively, and TL for conventional dyeing group was higher than alternative dyeing group as an average of 1.2 fold. After dyeing, TEM was significantly increased in both conventional dyeing group and alternative dyeing group compared with before dyeing as an average of 192% and 76%, respectively, and TEM for conventional dyeing group was significantly higher than alternative dyeing group as an average of 1.7 fold. Therefore, alternative dyeing application was induced to lower lymphocyte DNA damage than conventional dyeing application, and TEM was appeared to be a more sensitive tool for the measurement of lymphocyte DNA damage than TL in this study.

• Applied Microscopy
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• v.25 no.1
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• pp.111-121
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• 1995

The ultrastructure of spermatozoa in Hynobius leechii was examined with transmission electron microscope and compared with those of other urodeles and anurans. The perforatorium and the tail show most of the common feature of urodeles. However, there were several ultrastructural characteristics in an acrosome, nucleus, neck, axial rod and mitochondria related to the nucleus. The acrosome was trifoliate in transverse sections and the perforatorium consisted of two different concentric parts with a fine sharp point in a subacrosomal lumen. The nucleus consisted of two different regions of chromatin area and nuclear ridge. The nuclear ridge was composed of several bundles of five to ten minute tubular subunits of 19 nm diameter in this species, while in higher urodeles it was well developed in multi layers. The protoplasmic bead was separated by a cytoplasmic canal except the connection with only the distal portion of the nucleus. The neck was a short cylinder and contained pericentriolar material with transverse striations. In Hynobius the ring was not elongated to the tail and the mitochondria were distributed only in the protoplasmic bead around the nucleus as in Cryptobranchus, while in higher groups of urodeles it elongates to the length of the middle piece and the mitochondria follow the ring. The ring elongation may be related to the distribution of mitochondria. Hynobiidae and Cryptobranchidae are closely related based on structure of neck, the axial rod and location of mitochondria, although they are different in the composition of the axial rod.

• Journal of Animal Science and Technology
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• v.61 no.3
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• pp.147-153
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• 2019

A goal for swine farming is the improvement in the number of live-born and weaned piglets per sow. Hence, the effect of parities should consider the correlation between the component traits of reproductive performance, weaning, and duration. Sows were housed in farrowing pens (W 2.2 ${\times}$ D 1.8 ${\times}$ H 1.2 m) on a partially slatted plastic floor. Twenty sows used in this study were between the first and sixth parity in gilts (P1), parity 2-5 (P3), and parity 6-9 (P6). Data collection by parity was classified into three categories: (1) reproduction performance (gestation length, total number of piglets born, number of piglets live born, number of piglets stillborn, total piglet birth weight; (2) weaning traits (weaning period, number of piglets weaning, total piglets weaning weight); (3) duration traits (farrowing duration, placenta expulsion duration, time from last piglet to first placenta, average birth interval, and tail wagging behavior). Gestation length was higher in P6 than P1 and P3 of different parity sows. The maximum value in P1 and P3 was 117 days, but the median value in P6 was 117 days (p < 0.05). The total number of piglets born (p = 0.113), number of piglets live born (p = 0.118), number of still piglets born (p = 0.151), and total piglet birth weight (p = 0.117) were not affected by parity. The number of live piglets was higher than the other parities by an average of $15.6{\pm}2.1$ in P1. The duration of farrowing was the lowest at 22.2 min in P6, but the maximum value was 42.2 min more than other parities (p = 0.355). Weaning traits of sows also did not differ significantly (p > 0.05), but the weaning period from P1 was lower than that of the other parities (p = 0.170). The number of piglets weaned was 10 heads on average in P1, P3, and P6 (p < 0.05). However, the mean values of the total piglet weaning weight (p = 0.377) of P6 (62.0 10.4 kg) were higher than those of P1 (54.9 10.2 kg) and P3 (58.4 13.6 kg). The placenta expulsion duration was higher in P6 than that in P1 and P3 (p = 0.447). The time from the last piglet to first placenta was be lower in P3 than that of the other parities (p = 0.206). The average birth interval was higher in P3 than that of the other parities (p = 0.156). Tail wagging (count) behavior was higher in P6 than in the other parities (p = 0.065). The data showed that the reproduction performance, total piglets born, and weight were higher in the gilts group, and higher in the weaning trait than that in the P6 group. This study examined the relationship between reproductive performance, birth interval and tail motion according to sow parity. Regarding duration, farrowing duration was lower in P6 than that in the other parities, but placenta expulsion and tail wagging were higher in P6 than in the other parities. Therefore, it is possible that the results from these sows could be used as basic data for effective farm management.

• Journal of Ecology and Environment
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• v.44 no.1
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• pp.41-44
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• 2020

The Chinese many-toothed snake (Sibynophis chinensis) is an endangered species in South Korea. To determine its reproductive activity, here we captured a gravid S. chinensis from Mulyeongari Oreum Wetland Conservation Area, Jeju Island, on May 27, 2018, and reared it at Animal Taxonomy and Morphology Laboratory, Jeju National University, South Korea. The snake oviposited a clutch of six eggs between June 12 and 20, 2018, with an average size of 24.86 ± 1.36 mm in length and 9.86 ± 0.49 mm in width, which were artificially incubated at a constant temperature of 27 ℃. After incubating for 34-41 days, five of these six eggs successfully hatched. Average snoutvent length (SVL), tail length (TL), and body weight (BW) of hatchlings were 136.5 ± 5.17 mm, 47.76 ± 2.80 mm, and 1.66 ± 0.12 g, respectively. This study observed the reproductive activity of S. chinensis and characterized its eggs and hatchlings for the first time, providing valuable information for the long-term conservation plan of S. chinensis in South Korea.