• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.6 no.2
• /
• pp.238-246
• /
• 1996

High-density SiC-AIN solid solutions were fabricated from powder mixtures of $\beta$-SiC and AIN by hot-pressing in the 1870 to $2030^{\circ}C$ temperature range. The reaction of AIN and $\beta$-SiC (3C) powder transformed to the 2 H (wurzite) structure appeared to depend on the temperature and SiC/A1N ratio and seeds present. The crystalline phases consisted of a SiC-rich solid-solution phase and an A1N-rich solid-solution phase. At $2030^{\circ}C$ for 1 h, for a composition of 50 % AIN/50 % SiC with a seeding of $\alpha$-SiC, the complete solid solution could be obtained and the microstructures are equiaxed with a relatively homogeneous grain size of 2 H phases. The variation of the seeding of $\alpha$-SiC in SIC-A1N solid solutions could be attributed to the transformation behaviour and differences in size and shape of the grains, as well as to other factors, such as grain size distributions, compositional inhomogeneity, and structural defects.

• Journal of the Korean Geosynthetics Society
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2015

Recently, several researches on the development of new economical anchor systems have been performed to support floating structures. This study focused on the group suction piles, which connect mid-sized suction piles instead of a single suction pile with large-diameter. The group suction pile shows the complex bearing behavior with translation and rotation, so it is difficult to apply conventional design methods. Therefore, the numerical modeling technique was developed to evaluate the horizontal bearing capacity of the group suction piles in clay. The technique models suction piles as beam elements and soil reaction as non-linear springs. To analyze the applicability of the modeling, the horizontal load-movement curves of the proposed modeling were compared with those of three-dimensional finite element analyses. The comparison showed that the modeling underestimates the capacity and overestimate the displacement corresponding to the maximum capacity. Therefore, the correction factors for the horizontal soil resistance was proposed to match the bearing capacity from the three-dimensional finite element analyses.

• Korean journal of applied entomology
• /
• v.4
• /
• pp.51-54
• /
• 1965

The study was initiated to investigate the nature of varietal resistance to the rice stem borer (Chilo suppressalis WALKER), specially the rotation of the resistance to the silica and nitrogen content of the host Plants. 1. The body freight of the larvae, reared on the stem of the various varieties of rice plants, when weighed at the age of 25 days old, showed great variation, and ranged from 21.24 mgrs. to 45.77 mgrs. depending on the used varieties of tile rice plants. And generally the varieties of Indica types were showed greater body weight than that of Japonica types in this experiments. 2. The positive correlation coefficients of percent survivals to body weight, developement, oviposition preference and rate of damage to host plants were significant, and consequently the percent survival could be used as a criteria of resistance. 3. The content of silica in the host plants was significantly correlated with both the degree of boring on the leaf and attractovemess of larvae, and the total nitrogen content of plants showed significant positive correlation coefficient with larval attractivenes, but not significant with the degree of boring on the leaf. 4. Since the attractiveness and boring manner were significantyly correlated to resistance criteria of rice plant to the pest, it could be considered that the resistance is the results of chain reaction of the factors mentioned above.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.38 no.3
• /
• pp.296-302
• /
• 2011

Idiopathic gingival fibromatosisrarely occurs, but frequently recurred after surgical removal. It usually occurs in generalized symmetrical pattern but sometimes in localized unilateral pattern. The localized pattern usually affects the maxillary molar and tuberosity area. This disease usually causes tooth migration, malocclusion, and problems in eating, speech, and esthetics. A boy showed dense gingival fibromatosis localized at primary maxillary right lateral incisor area at the age of 5 years, and his maxillary right lateral incisor become severely displaced at the age of 9 years. He had no medical and hereditary factors relevant to the gingival fibromatosis. However, the dense fibrous tissue was dominant in his labial gingiva of maxillary right incisors. In order to realign the displaced incisors by orthodontic treatment, the dense fibrous tissue covered the defect space between the central incisor and the displaced lateral incisor was surgically removed. The removed specimen was examined by simple immunohistochemical(IHC) array method. IHC array showed increased expression of CTGF, HSP-70, MMP-1, PCNA, CMG2, and TNF-${\alpha}$ in keratinocytes, fibroblasts, endothelial cells, and macrophages of gingival fibromatosis tissue. Therefore, it was suggested that the gingival fibromatosis be caused by the concomitant overexpression of CTGF, HSP-70, MMP-1, PCNA, CMG2, and TNF-${\alpha}$, and resulted in the fibroepithelial proliferation and the inflammatory reaction of gingival tissue.

• Clinical and Experimental Pediatrics
• /
• v.51 no.9
• /
• pp.1007-1011
• /
• 2008

Purpose : Febrile seizure (FS) is the most common type of seizure. The role of genetic factors in FSs has long been recognized. A positive family history can be elicited in 25-40% of patients with FSs; nonetheless, the genes responsible for FSs in the majority of the population remain unknown. Interleukin-$1{\beta}$ ($IL-1{\beta}$) is a pro-inflammatory cytokine that acts as an endogenous pyrogen. Thus, $IL-1{\beta}$ could be involved in the pathophysiology of FSs. Methods : To determine whether or not single nucleotide polymorphisms of the $IL-1{\beta}$ gene are associated with susceptibility to simple FSs, $IL-1{\beta}$ promoter -31 and -511 genotyping was performed by means of polymerase chain reaction-restriction fragment (PCR-RF) length polymorphism in 40 FS patients (20 sporadic and 20 familial FS patients) and 33 controls. Results : There were no significant differences in the frequencies of -31 C/T and -511 C/T in the $IL-1{\beta}$ promoter gene, between simple FS patients and controls. Conclusion : The frequency of CT/CT increased relatively in familial FS patients. A study examining a larger number of FS patients is needed.

• The Journal of Internal Korean Medicine
• /
• v.33 no.2
• /
• pp.126-144
• /
• 2012

Background : Peripheral nerves more rapidly recover than central nerves. However, it has been known that the degree of reaction of axons of peripheral nerves is affected by distinctive characteristics of axons and environmental factors near the axons. Taxol is a widely used medicine as for ovarian, breast, lung and gastric cancer. However it causes patients difficulties under treatment due to its toxic and side effects, which include persistent pain. Objectives : This study reviewed how SJT extract in vitro and in vivo affects nerve tissues of a sciatic nerve damaged by Taxol. It also studied how SJT extract in vivo affects axons of the sciatic nerve after the sciatic nerve was damaged by pressing. Methods : After vehicle, Taxol, and Taxol plus SJT were treated respectively for tissue of the sciatic nerve in vitro and then tissues were observed using Neurofilament 200, Hoechst, ${\beta}$-tubulin, $S100{\beta}$, caspase-3 and anti-cdc2. SJT was also oral medicated by injecting Taxol into the sciatic nerve of in vivo rats. Tissues of the sciatic nerve and axons of DRG sensory nerves were then observed using Neurofilament 200, Hoechst, ${\beta}$-tubulin, $S100{\beta}$, caspase-3 and p-Erk1/2. After inflicting pressing damage to the sciatic nerve of in vivo rats, tissues of the sciatic nerve and DRG sensory nerve were observed using Neurofilament 200, Hoechst, $S100{\beta}$, caspase-3, anti-cdc2, phospho-vimentin, ${\beta}1$-integrin, Dil reverse tracking and p-Erk1/2. Results : The group of in vitro Taxol plus SJT treatment had meaningful effects after sciatic nerve tissue was damaged by Taxol. The group of in vivo SJT treatment had effects of regenerating Schwann cells and axons which were damaged by Taxol treatment. The group of in vivo SJT had effects of regenerating axons in damaged areas after the sciatic nerve was damaged by pressing, and also had variations of distribution in Schwann cells at DRG sensory nerves and axons. Conclusions : This study confirmed that SJT treatment is effective for growth of axons in the sciatic nerve tissues and improvement of Schwann cells after axons of the sciatic nerve tissues was damaged. After tissues of sciatic nerve was damaged by pressing in vivo, SJT treatment had effects on promoting regeneration of axon in the damaged area and reactional capabilities in axons of DRG sensory nerves.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.3
• /
• pp.633-642
• /
• 2003

A pain is the symptom which defends against noxious stimulus about a human body, it is known that if the periphery of perceptive nerve were stimulated by a physical or chemical factors, the stimulation is induced by transmission to pain center in the cerebral cortex according to pain conduction tract. The treatment of pain is to decrease a stimulus that causes a pain or block off a nerve transmitting a stimulus or puts on a way to calm down pain center, but It is for adjustment of a pain to be the most representative in acupuncture among various ways to cure a pain in Oriental medicine. However, the analgesic effect of an individual response to acupuncture stimulation shows marked individual variations, so these days genetic a few approach is attempted. On this the author determined that the responding group was appointed those whose tail flick latency (TFL) responding time delayed the minimum of 30 % comparing with basal reaction time. For those whose TFL time had shorter than 30 % was grouped as a non-responding group. And then the hypothalamus of each group was dissected and RNA was further purified. After synthesizing cDNA using oligo dT primer, products were finally applied to the PCR. The results were as follows; The ratio of responding group to non-responding group was 6:4. Ach T (acetylcholinesterase T subunit), BF-I (Brain factor-I), DBH (Dopamine β-hydroxylase) and PNM (Phosphotidylethanolamine N-Methyltransferase) were revealed significantly in the responding group. Cathepsin B and Tau were revealed significantly in the non-responding group. The PCR results show that Ach T, BF-I, DBH and PNM are expressed abundantly in the responding group, where as cathepsin B and tau are abundant in the non-responding group. These results suggest that the analgesic effect on acupuncture stimulation is related to regulation of neurotransmitter as well as neurodegeration of cerebrum.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.16 no.1
• /
• pp.34-40
• /
• 2013

Purpose: We investigated the positivity rate and the time period to the positive color change of the urease test in children and adults and assessed the correlation of the urease test to histopathologic findings. Methods: From 1995 to 2000, endoscopic biopsies of the antrum and body were collected from 811 children and 224 adults and subjected to urease tests and histopathology. Results: The positivity rate of the urease test was 49.4% for 0-4 years, 48.4% for 5-9 years, 47.3% for 10-15 years, and 62.5% for 20-29 years in the antrum. The positivity rate was 85.1% in 0-4 years, 82.3% in 5-9 years, 74.7% in 10-15 years, and 74.1% in 20-29 years for the body. In the antrum, the highest positivity rate was <1 hour for the group aged 10-29 years and 6-24 hours in the group <10 years old (p<0.0001). In the body, the highest positivity rate was <1 hour in adults and 6-24 hours in children (p<0.0001). The proportions of the positive reactions within 1 hour were similar for the antrum and the body. In the cases of more severe chronic gastritis, active gastritis, and Helicobacter pylori infiltration, a positive urease test reaction occurred more quickly (p<0.0001). Conclusion: There were significant differences in urease tests according to age and sampling site. The discrepancy between the antrum and the body was greater in younger children. These results might be related to the low density and patchy distribution of bacteria in children and in the body.

• Applied Chemistry for Engineering
• /
• v.29 no.1
• /
• pp.49-55
• /
• 2018

In this study, we investigated the cellular protective effects and mechanisms of nicotiflorin and its aglycone kaempferol isolated from Annona muricata. The protective effect of these components against $^1O_2$-induced cell damage was also studied by using L-ascorbic acid and (+)-${\alpha}$-tocopherol as controls. Kaempferol exhibited the most potent protective effect, followed by (+)-${\alpha}$-tocopherol and nicotiflorin. L-Ascorbic acid did not exhibit any cellular protective effects. To elucidate the mechanism underlying protective effects, the quenching rate constant of the singlet oxygen, free radical-scavenging activity, ROS-scavenging activity, and uptake ratio of the erythrocyte membrane were measured. The results showed that the cell membrane penetration is a key factor determining the cellular protective effect of kaempferol and its glycoside nicotiflorin. The result from L-ascorbic acid demonstrated that the cellular protective effect of a compound depends on its ability to penetrate the cell membrane and is independent of its antioxidant capacity. In addition, it is suggested that cellular protective effects of kaempferol and (+)-${\alpha}$-tocopherol depend not only on the cell permeability, but also on free radical- and ROS-scavenging activities. These results indicate that the cell permeability and free radical- and ROS- scavenging activities of antioxidants are major factors affecting the protection of cell membranes against the oxidative damage induced by photosensitization reaction.

• Journal of Life Science
• /
• v.14 no.5
• /
• pp.847-854
• /
• 2004

Allergy is a multi-factorial disease influenced by genetic and environmental factors. As the number of allergy-affected people is increasing in developed countries, there is an increasing interest in genetic predisposition to the allergy. A number of genes and chromosomal region have been identified to be linked to allergy including rhinitis, asthma and atopy. In order to understand the genetic background for the allergy-affected people, we investigated genetic predisposition among students enrolled in Busan Science Academy. Among 138 students, about 30% students had some allergy-related disorder including rhinitis, asthma and atopy. We analyzed several single nucleotide polymorphisms (SNPs) within two genes, Inter-leukin-4(IL-4) and Interleukin-4 receptor(IL-4R), which are involved in the induction of allergy reaction with the Th2 immunity. For 96 samples obtained from students, we analyzed 9 SNPs including -590 C/T and -34 C/T in IL-4, and I75V, Q576R, E375A, e406R, 5411L, S761P and S727A in IL-4R. From the analysis, these SNPs showed slight differences among normal and allergy-affected students, but these differences was not enough to predict the predisposition to the allergy. In contrast to previous reports, we could not find SNP(s) related with allergy. These results suggest that genetic tests recently performed in Korea widely have to be reassessed for its validity of genetic predisposition. [Supported by grants from MOST]