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  • Title/Summary/Keyword: 구조적 붕괴

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Electron microscopic studies on Flavobacterium branchiophila in experimentally induced gill disease of rainbow trout (세균성(細菌性) 아가미병(病)에 실험적(實驗的)으로 감염(感染)된 무지개송어에 있어서 Flavobacterium branchiophila에 대한 전자현미경학적(電子顯微鏡學的) 연구(硏究))

  • Heo, Gang-joon
    • Korean Journal of Veterinary Research
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    • v.32 no.3
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    • pp.381-387
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    • 1992
  • Gill epithelia of normal rainbow trout fingerlings and abnormal ones suffering bacterial gill disease by experimental infection were examined by transmitting electron microscopy (TEM) and scanning electron microscopy (SEM). TEM observations revealed that Flavobacterium branchiophila consisted of slender rods measuring 0.5 by 5 to 8μm, and they had which were long, thin, flexible filaments measuring approximately 4 nm by 1μm, and packed together to organize into bundles. Morphological alterations of the diseased epithelia started at hypertrophy of the lamellar epithelium. F branchiophila attached to the gill surface of infected fish through pili with a regular distance, and did not invade into gill tissue. In SEM observations, normal surface ultrastructure of epithelial cell in the outermost layer were characterized by a typical labyrinth-like structure branching and anastomosing microridges on the cell surface. Hyperplastic lesions in experimentally infected gill were most serious at near the tips. Each filament exhibited a club-like, and fusion between the filaments was sometimes observed at their tips. On the surface of gill filaments, thread-like bacterial cells attached and were entangled. The bacterial cells almost covered the surface. After immersion in 5 % NaCl, the cell of F branchiophila, however, appeared to be indeterminate shape.

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Isolation and Characterization of MMP-1 Inhibitor Peptide from Crataegus pinnatifida Bunge in Fibroblast Cell Line HS68 Cells (아가위(Crataegus pinnatifida Bunge)로 부터 HS 68세포의 MMP-1에 대한 저해활성 물질의 분리)

  • Lee, Se-Young;Chun, Hyug;Cho, Hong-Yun;An, Jeung-Hee
    • Applied Biological Chemistry
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    • v.46 no.1
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    • pp.60-65
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    • 2003
  • MMP-1 inhibitory compounds were isolated from 120 Korean traditional edible plants. UP- 1 activity significantly increased linearly with increasing UVB dose in normal human foreskin fibroblast HS68 cell, showing maximum activity at approximately 35 mJ/cm2, whereas in HaCaT cell, normal human keratinocyte, no increase was observed. Maximum secretion of MMP-1 after UVB treatment occurred around 36-48 k after treatment. MMP-1 inhibitory compound isolated from cold-water fraction of Cataegus pinnatifida Bunge showed the mort potent activity. The MMP-1 inhibitory compound was deduced as a peptide based on the fact that pronase digestion decreased the activity whereas periodate oxidation did not. The most potent UP- 1-inhibitory protein, CP-2Va-2, showing an activity of 88.5% against MMP-1, was isolated through sequential column chromatography on DEAE-Toyopearl 650C, Butyl-Toyopearl 650M, and Bio-Gel P-30. Molecular weight of CP-2Va-2 determined through high performance liquid chromatography and SDS PACE was 19 and 20 kDa. respectively, signifying a monomeric structure.

A proposal of simple evaluation on the seismic performance of tunnel lining (터널 라이닝의 내진성능 간편 평가법 제안)

  • Ahn, Jae-Kwang;Byun, Yoseph;Lee, Gyuphil;Lee, Seongwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.2
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    • pp.361-374
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    • 2018
  • The country has built and is operating IT-based integrated management system for efficient management of national highway tunnels used publicly these days. Since this system doesn't include the management function on earthquakes, it is impossible to promptly respond to earthquakes and to select the sections requiring seismic reinforcement. Tunnels designed and constructed after 1999 have been subjected to seismic design for an earthquake with a return period 1000 years. Therefore, it is necessary to evaluate the stability of structures in case of earthquakes more than this. Since it takes a lot of time to perform the stability evaluation on various earthquake magnitudes, a method that can easily evaluate earthquakes is needed. In this paper, the empirical simplification method that can easily evaluate the earthquake was proposed. For this, the study calculated ground displacement by conducting one-dimensional ground response analysis, and examined the safety of tunnels in the event of occurrence of an earthquake using two means of response displacement method (analytics and numerical analysis).

Mineralogical Study on Interpretation of Firing Temperature of Ancient Bricks: Focused on the Bricks from the Songsanri Tomb Complex (고대 벽돌의 소성온도 해석을 위한 광물학적 연구: 송산리 고분군 벽돌을 중심으로)

  • Jang, Sungyoon;Lee, Chan Hee
    • Journal of Conservation Science
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    • v.30 no.4
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    • pp.395-407
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    • 2014
  • In this study, firing temperature of bricks from the Songsanri tomb complex is interpreted based on the mineralogical and physical changes of soil samples fired at different temperature. When soil samples were burned at 500 to 1,200C, phase transition of clay minerals affected the mineralogical composition and microstructure, which leaded to alteration of physical features as color, water absorption and porosity. Mineralogical composition can be assumed to vary with the temperature by mineral phase stability, however, color, water absorption, porosity and microstructure had slow change under 1,000C, and had rapid change from 1,000 to 1,200C. Upon the mineral and physical alteration of soil, firing temperature of bricks from the Songsanri tomb complex were estimated. Some bricks were over fired at temperature more than 1,200C, some high-burned bricks were fired from 1,100 to 1,200C, some bricks were fired by 900 to 1,000C and some bricks ere assumed not to be fired. Henceforward mineralogical and physical study can be applied to interpretate more precise firing temperature.

Rehabilitation of severely worn dentition using Monolithic surveyed restoration and electronic surveying in RPD metal framework fabrication: A case report (심한 마모를 가진 환자에서 전자 서베잉을 이용한 금관 및 국소의치 수복 증례)

  • Choi, Youngha;Kim, Hyeong-Seob;Kwon, Kung-Rock;Pae, Ahran;Noh, Kwantae;Paek, Janghyun;Hong, Seoungjin
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.3
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    • pp.243-249
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    • 2018
  • Excessive tooth wear results in unacceptable damage to the occlusal surface and can cause pulpitis, occlusal disharmony, dysfunction, and unesthetic result. Patients with severe attrition have to be classified as several types relative to the vertical dimension of occlusion (VDO) and the interocclusal distance for the prosthetic space. The patient in this case was a 80 - year - old woman who lost support of posterior occlusion and collapsed of the occlusal plane due to confrontation of the opposing teeth, accompanied by an increase in the number of remaining bristles, resulting in a loss of intermaxillary space for prosthesis. In this case, treatment with increased vertical dimension may have stability if the increase in vertical occlusal height is minimized within the required range, and a stable occlusal contact is provided after an increased vertical occlusal height stabilization period. After the new VDO had been confirmed under interim fixed restorations, definitive fixed restorations were produced. Through these treatment processes, we obtain satisfactory results that are functional and aesthetically pleasing.

Analysis of the orf 282 Gene and Its Function in Rhodobacter sphaeroide 2.4.1 (R. sphaeroides 에서의 orf282 유전자의 분석과 이들의 기능)

  • Son, Myung-Hwa;Lee, Sang-Joon
    • Journal of Life Science
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    • v.22 no.8
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    • pp.1009-1017
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    • 2012
  • The orf282 gene of Rhodobacter sphaeroides is located between the ccoNOQP operon encoding cbb3 terminal oxidase and the fnrL gene encoding an anaerobic activator, FnrL. Its function remains unknown. In an attempt to reveal the function of the orf282 gene, we disrupted the gene by deleting a portion of the orf282 gene and constructed an orf282-knockout mutant. Two FnrL binding sites were found to be located upstream of orf282, and it was demonstrated that orf282 is positively regulated by FnrL. The orf282 gene is not involved in the regulation of spectral complex formation. The cbb3 oxidase activity detected in the orf282 mutant was comparable to that in the wild-type sample, indicating that the orf282 gene is not involved in the regulation of the ccoNOQP operon and the biosynthesis of the cbb3 cytochrome c oxidase. The elevated promoter activity of the nifH and nifA genes, which are the structural genes of nitrogenase and its regulator, respectively, in the orf282 mutant, suggests that the orf282 gene product acts as a negative effector for nifH and nifA expression.

THE EFFECT OF LEUCONOSTOC LACTIS 51 AGAINST THE PLAQUE FORMATION OF STREPTOCOCCUS MUTANS (Streptococcus mutans의 치태형성에 대한 Leuconostoc lactis 51의 영향)

  • Kim, Tae-Geun;Yang, Kyu-Ho;Oh, Jong-Suk
    • Journal of the korean academy of Pediatric Dentistry
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    • v.27 no.4
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    • pp.549-557
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    • 2000
  • Dental caries is a bacterial disease of the dental hard tisssus, characterized by a localized, progressive, molecular disintegration of tooth structure. The action of Leuconostoc lactis 51 about plaque formation and replication by Streptococcus mutans was studied as follows. 1. Lower amount of plaque was produced at the mixed culture of S. mutans and L. lactis 51 than S. mutans alone on the wires in the beaker. 2. Fewer cells of S. mutans were replicated at the mixed culture of S. mutans and L. lactis 51 than S. mutans alone. 3. In M17Y broth, viable cells of S. mutans and L. lactis 51 increased for 12 hours, and decreased for 24 hours. In M17YS broth, viable cells of S. mutans showed time-dependent decrease at mixed culture of S. mutans and L. lactis 51. 4. The culture supernatant of L. lactis 51 didn't inhibit the replication of S. mutans and the formation of artificial plaque. 5. Sucrose and frutose were extracted from the culture supernatant of L. lactis 51 in M17YS broth. These results suggest that L. lactis 51 isolated from the oral cavity inhibits the replication of S. mutans and the formation of artificial plaque.

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A multiphase flow modeling of gravity currents in a rectangular channel (사각형 수로에서 중력류의 다상흐름 수치모의)

  • Kim, Byungjoo;Paik, Joongcheol
    • Journal of Korea Water Resources Association
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    • v.52 no.10
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    • pp.697-706
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    • 2019
  • A multiphase flow modeling approach equipped with a hybrid turbulence modeling method is applied to compute the gravity currents in a rectangular channel. The present multiphase solver considers the dense fluid, the less-dense ambient fluid and the air above free surface as three phases with separate flow equations for each phase. The turbulent effect is simulated by the IDDES (improved delayed detach eddy simulation), a hybrid RANS/LES, approach which resolves the turbulent flow away from the wall in the LES mode and models the near wall flow in RANS mode on moderately fine computational meshes. The numerical results show that the present model can successfully reproduce the gravity currents in terms of the propagation speed of the current heads and the emergence of large-scale Kelvin-Helmholtz type interfacial billows and their three dimensional break down into smaller turbulent structures, even on the relatively coarse mesh for wall-modeled RANS computation with low-Reynolds number turbulence model. The present solutions reveal that the modeling approach can capture the large-scale three dimensional behaviors of gravity current head accompanied by the lobe-and-cleft instability at affordable computational resources, which is comparable to the LES results obtained on much fine meshes. It demonstrates that the multiphase modeling method using the hybrid turbulence model can be a promising engineering solver for predicting the physical behaviors of gravity currents in natural environmental configurations.

Investigation Study on Underground Cavity Scale Estimation Based on GPR Exploration (지하공동 규모 평가를 위한 GPR 탐사 기반의 조사 연구)

  • Byoung-Jo Yoon;Han-Joo Lim;Yeon-Gyu Kim
    • Journal of the Society of Disaster Information
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    • v.19 no.3
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    • pp.737-746
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    • 2023
  • Purpose: Ground subsidence due to cavity can bring about various problems, such as casualties, decrease of the safety of the structures, and indirect social costs. Therefore, ground subsidence should be prevented through the exploration and recovery of the cavity under the pavements. Method: In this study, GPR exploration method was carried out on both actual roadway and mock-up site to compensate for the problems caused by excavation and restoration process. Result: This study compared the cavity scales obtained from GPR exploration results and the direct excavation of the identified cavity. It was confirmed that the predicted soil depth by GPR exploration was similar to the identified soil depth, but the predicted cavity scale by GPR exploration overestimated the longitudinal and cross-sectional widths compared to the identified cavity scale. Conclusion: Based on the correlation between the predicted cavity scales by GPR exploration, it is possible to qualitatively estimate the cavity scales using the empirical formula proposed in this study.

A Review on the Improvement of the Meaning and Composition Requirements of Interference with Fire Protection Activities - Focusing on Interference with 119 EMS Activities - (소방활동방해죄의 의미와 구성요건 개선에 관한 검토 -119구급활동 방해를 중심으로-)

  • Young Pyo Hong
    • The Korean Society of Law and Medicine
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    • v.24 no.3
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    • pp.105-124
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    • 2023
  • Modern society is facing an unstable environment due to unexpected accidents and hazardous situations. For example, incidents such as the collapse of the Bundang Bridge and the crushing accident in Itaewon could serve as examples. In addition to these, critical emergencies like sudden cardiac arrests and strokes frequently occur, requiring swift actions and smooth transfers to specialized medical institutions for effective responses. In response to these risks, the country has been establishing various systems to protect the lives and safety of its citizens. Among these, the 119 First Aid Activities plays a crucial role within the emergency medical system. Its goal is to promptly respond to critical emergency situations involving severe trauma patients or patients with serious illnesses, minimizing damage and safeguarding lives by swiftly transferring them to emergency medical institutions for specialized treatment. The core activity related to this is emergency rescue operations. In particular, the 119 First Aid system serves as a crucial institution responsible for the hospital transportation of emergency patients. However, rescue personnel still encounter cases of interference with their activities during their duties. Despite efforts from the police, these interference cases persist, and they share similarities with the crime of obstructing official duties. Interference with emergency activities exhibits a comparable nature to instances such as physical assaults and equipment damage against emergency medical practitioners working within the emergency medical system. Therefore, a comprehensive understanding and improvement efforts regarding the issues of interference that arise during the process of emergency medical activities, including the 119 First Aid system, are necessary. The solution to these problems is to establish and improve the conditions for obstruction of first aid activities, focusing on the "Framework Act on Firefighting" and the "Act on 119 Rescue and Emergency."