• The Korean Journal of Zoology
• /
• v.35 no.1
• /
• pp.45-57
• /
• 1992

생쥐를 48시간 동안 결식시킨 후 유문결찰하여 급성미란을 유발시키고 미란형성부의 점막 내위선을 구성하는 각 세포의 구조변화와 IgA 분비세포의 분포를 관찰하였다. 미란부 점액분포의 변화는 표면상피의 손상 정도가 심해질수록 경계부의 PAS양성반응은 감소되었으며 중심부에서는 표면상피의 소실로 인하여 PAS 양성반응이 관찰되지 않았다. Glycocalyx 관찰을 위한 ruthenium red 반응에서도 경계부의 상피세포 손상이 심해짐에 따라 정단세포막 상층에 나타나는 양성반응은 감소되었고 측면과 기저면의 양성반응은 관찰되지 않은 것으로 보아 세포 손상시 tight junction은 파괴되지 않음을 알 수 있었다. 미란경계부의 미세구조변화로서, 상피세포는 손상이 진행될수록 세포질이 용해되어 공포가 형성되고 핵응축 및 정 단세포질의 점액원과립의 소실이 관찰되었으나 tight junction은 유지되었다. 반면에 점액경세포는 점액원과립의 수가 증가되고 조면소포체가 종창되어 있었다. 미란의 경계부와 중심부에서 벽세포는 다수의 소포가 출현한 후 세포내세관이 종창되었으며 그 후에 mitochondria가 파괴되었고 주세포는 주변의 벽세포가 커지면서 가장자리로 밀려나 크기가 정상보다 작아지고 조면소포체와 mitochondria가 종창을 나타내었다. IgA분비세포는 점막이 파괴된 미란부 점막하조직의 혈관 주변에 다수 존재하는 형질세포에서 확인되었다.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.23 no.6
• /
• pp.485-502
• /
• 2021

In order to evaluate the impact of ground subsidence and superstructures that are inevitably caused by tunnel excavation, a total of seven major influencing factors of surface subsidence and structural soundness reduction were set, and a Parameter Study using numerical analysis was conducted. Stability analysis was performed using scheme of Boscardin and Cording method and the maximum subsidence amount and the angular displacement, and correlation analysis was performed for each major influencing factor. In addition, it was applied that used the mutual behavior of the ground and the structure by parameter analysis in the site of the 𐩒𐩒𐩒 tunnel located in Hwaseong-si, Gyeonggi-do, and the applicability of the site was analyzed. As a result, the error was found to be 1.0%, and it could be used as a basic material for determining the appropriate tunnel route under various conditions when evaluating the stability of the structure according to tunnel excavating at the design stage.

• Clinical and Experimental Pediatrics
• /
• v.49 no.3
• /
• pp.278-286
• /
• 2006

Purpose : Although suprapubic bladder aspiration(SBA) is the most reliable technique for identifying bacteriuria in young infant, no report has been published about the clinical manifestations of urinary tract infection(UTI) diagnosed by aspirated urine in Korea. This study was performed to examine clinical manifestations and related factors of UTI confirmed by a positive urine culture obtained by SBA in young infants. Methods : We reviewed medical records of 159 infants younger than six months of age, who had been admitted for UTI to Korea University Ansan Hospital from January 2002 to June 2005. Results : The male:female ratio was 5.1 : 1. The most common pathogen in urine culture was Escherichia coli(92.5 percent). Most of the gram-negative pathogens had high sensitivity to amikacin, or third generation cephalosporins and had low sensitivity to ampicillin, trimethoprim-sulfamethoxazole, or gentamicin. Hydronephrosis and vesicoureteral reflux(VUR) were present in 32.7 percent and 27.7 percent respectively. Renal cortical defects observed on DMSA scans were detected in 37.1 percent. Prolonged fever duration and hospital day, high erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) levels, hydronephrosis and VUR were related to the renal cortical defects(P<0.05). Rates of UTI-associated bacteremia and aseptic meningitis were 8.3 percent and 6.6 percent. Conclusion : Early differential diagnosis is very important in infants younger than 6 months of age with UTI because the clinical findings are non-specific and UTI-associated bacteremia and aseptic meningitis are concomitantly found. Because prolonged fever and higher ESR and CRP levels are risk factors of the renal cortical defects, radiologic evaluations and nephrologic follow-up were needed in identifying the predisposing congenital abnormalities and chronic renal scarring.

• Microbiology and Biotechnology Letters
• /
• v.20 no.6
• /
• pp.642-646
• /
• 1992

We have isolated conditional lethal mutants of Saccharomyces cerevisiae which are low in (1 ~3)-~-D-glucan synthase activity. These mutants were osmotic sensitive at nonpermissive temperature (37$^{\circ}$C) and showed a decreased level of alkali-insoluble cell wall glucan. The decrease in (1 ~3)-~-D-glucan synthase activity of the mutants appeared to be mainly due to the defect in catalytic component rather than in GTP-binding component.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.425-428
• /
• 2008

Concrete bridge decks, as well as asphalt pavement, are directly exposed to traffic loads and environmental conditions like rain water and deiceing chemicals. In this reason, there are often observed the deteriorations of asphalt overlay and of concrete deck under pavement. In this reason, it is important to identify the clear cause of concrete quality from a practical point of view. Therefore, in this paper it was initiated to ultimately suggest a protocol offering guidance as to assurance the quality control of concrete bridge deck on the part of void characteristics of concrete. Examinations such as visual inspection, deteriorated depth, and various void characteristic performed from cored specimens of 19 concrete bridge decks of various local conditions on the expressway. This paper discuss that the bridge deck condition analyses from the testing results were compared to a foreign guide line.

• Journal of Life Science
• /
• v.21 no.7
• /
• pp.985-991
• /
• 2011

The purpose of this study was to investigate the biological effect of obesity-induced oxidative damage on neurogenesis and early protein expression. Obesity was induced I thirty 4-week old male Sprague-Dawley rats through a high fat diet for 15 weeks. After one week of environmental adaptation, the rats were divided into 2 groups: high fat diet sedentary group (HDS, n=15) and high fat diet training group (HDT, n=15). Exercise training was performed 5 times a week for 8 weeks, with mild-intensity treadmill running for weeks 1-4 and moderate-intensity treadmill running for weeks 5-8. After the 8 week training period, we analyzed lipid profiles, serum 8-hydroxyguanosine (8-OHdG), liver tissue malondialdehyde (MDA) related to oxidative damage factors, nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), c-fos, c-jun, and extracellular signal regulated kinase (Erk) in the hippocampus. The results of this study are as follows. There were differences between HDS and HDT in triglyceride (TG) and total cholesterol (TC) (p<0.05). In high density lipoprotein (HDL-c), the HDT was higher than HDS after treadmill training (p<0.05). In 8-OHdG, the HDT was lower than HDS after treadmill training (p<0.05). Genetic expressions of c-jun, BDNF and MDA in the HDT were higher than in the HDS after treadmill training in hippocampus (p<0.05). Therefore, we conclude that 8 weeks of treadmill training can improve imbalanced lipid profiles, reduce oxidative damage, and activate neurogenesis in obese rats.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.6
• /
• pp.95-103
• /
• 2019

Periodontal inflammation, a major kind of periodontal diseases, is characterized to bleed, pain, and teeth loss, and it is resulted from oxidative stress. Membrane-free stem cell extract could avoid the immunogencity rejection by removal of cell membrane. In the present study, we investigated the protective effect of membrane-free stem cell extract from oxidative stress-induced periodontal inflammation in human periodontal ligament fibroblasts (HPLF). In the cell viability measurement, membrane-free stem cell extract showed significant increase of cell viability, compared with the $H_2O_2$-treated control group. To further investigation of molecular mechanisms, we measured inflammation and apoptosis related protein expressions. Membrane-free stem cell extract attenuated inflammation-related protein expressions such as nuclear factor kappa light chain enhancer of activated B cells, inducible nitric oxide synthase, and interleukin-6. In addition, the treatment of membrane-free stem cell extract decreased apoptotic protein expressions such as cleaved caspase-9, -3, poly (ADP-ribose) polymerase, and B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 ratio in the $H_2O_2$-treated HPLF cells. In conclusion, membrane-free stem cell extract exhibited anti-oxidative stress effects by regulation of inflammation and apoptosis in HPLF, suggesting that it could be used as the treatment agents for periodontal inflammatory disease.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.2
• /
• pp.237-247
• /
• 1993

Carbon fiber reinforced plastics(CFRP) have gained increased application in aerospace structures because of their specific strength and stiffness, but are sensitive to impact-induced damage. An experimental investigation was carried out to evaluate the impact resistance of CFRP according to the ply angle. The specimens of angle ply laminate composites were employed with [0.deg. $_{6}$/ .deg.$_{10}$/0.deg.$_{6}$], in which 6 kinds of ply angle such as .deg.=15.deg., 30.deg., 45.deg., 60.deg., 75.deg. and 90.deg. were selected. The impact tests were conducted using the air gun type impact testing machine by steel balls of diameter of 5 mm and 10 mm, and impact-induced damages were evaluated under same impact speed of V=60m/s. The impact damaged zones were observed through a scanning acoustic microscope (SAM). The obtained results were summarized as follows: (1) Delaminations on the interfacial boundaries showed th directional characteristics to the fiber directions. The delamination area on the impact side (interface A) was considerably smaller compared to that of the opposite side (interface B). (2) Cracks corresponding to other delaminations than those mentioned in SAM photographs were also seen on the impact damaged zone. (3) The delamination patterns were affected by the ply-angle, the dimensions of the specimen, and the boundary conditions. (4) The impact damaged zone showed zone showed the delamination on the interfacial boundaries, transverse shear cracks of the surface layer, and bending cracks of the bottom layer.r.r.r.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.6
• /
• pp.757-762
• /
• 2010

Owing to the high specific strength and stiffness of composite materials, they are extensively used in mechanical systems and in vehicle industries. However, most mechanical structures experience repeated load and fatigue. Therefore, it is important to perform fatigue analysis of fiber-reinforced composites. The properties of composite laminates vary depending upon the stacking sequence and stacking direction. Fatigue damage of composite laminates occurs according to the following sequence: matrix cracking, delamination, and fiber breakage. In this study, fatigue tests were performed for damage analysis. Fatigue damages, which have to be considered in fatigue analysis, are determined by using the stiffness values calculated from hysteresis loops, and the obtained fatigue damage curve is examined using Mao's equation and Abdelal's equation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.6
• /
• pp.565-570
• /
• 1990

The role of the active oxygens on plasmid DNA damage by carbonyl compounds derived from Maillard reaction was investigated. Plasmid DNA extracted from E. coli Hb1O1 was reacted with carbonyl compounds, such as glyoxal, methyl glyoxal, dihydroxyacetone, diacetyl, glyceraldehyde, glycolaldehyde and furfural with and without the active oxygen scavengers at 37$^{\circ}C$ for 6 hours, and then the degree of damage was determined by using 1 ％ agarose gel electro-phoresis. All of the carbonyl compounds except furfural caused to damage of DNA. Among these, glyoxal, methyl glyoxal and dihydroxyacetone markedly induced the damage of DNA. On the other hand, the DNA damage by the carbonyl compounds was greatly inhibited by catalase, superoxide dismutase and $\alpha$-tocopherol it is considered that the damage of DNA is due to active oxygens, such as singlet oxygen, hydrogen peroxide and superoxide anion generated during the autoxidation of carbonyl compounds.