• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6C
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• pp.305-314
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• 2012

This paper presents the quantitative damage assessment of granite taken from KAERI Underground Research Tunnel using acoustic emission (AE). The results determined showed the crack initiation and crack damage stress occurred at 48%, 72% of uniaxial compressive strength (UCS) and until the applied stress level was reached the crack damage stress, the damage degree was 0.06. When the applied stress exceeded 80%, 90% of UCS, the damage degree were 0.34, 0.06 and which were similar to those obtained from axial deformation modulus. The simply regression analysis was used to interpret the relationship of the two damage assessment techniques and the two were highly correlated ($R^2$=0.90). Therefore, damage degree based on the AE energy and mohr-coulomb failure criterion were adopted to predict the mechanical properties. As results, the axial deformation modulus, rock strength, internal friction angle, and cohesion of KURT rock were reduced 6%, 12%, 7%, and 3% until the applied stress was 70% of UCS. But when the applied stress reached 90% of UCS, the results were more reduced 69%, 72%, 62%, and 24%, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.77-82
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• 2004

This study presents reliability assessment of merchant ships with focus on hull girder ultimate limit state, taking into account the time-dependent effects of corrosion, fatigue cracking and local denting. Some considerations for establishing a reliability-based repair and maintenance scheme are also made so as to keep a ship's hull girder strength reliability at an acceptable level even later in life.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.290-291
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• 2005

본 연구에서는 음극전리수가 paraquat에 의한 사람 임파구 DNA의 손상에 미치는 영향을 alkaline comet assay를 사용하여 조사하였다. 또한 음극전리수가 plasmid DNA 손상에 미치는 효과도 조사하였다. 사람 임파구에 다양한 농도의 paraquat을 처리한 후, 음극전리수를 첨가하여 반응시킨 결과 paraquat에 의한 임파구 DNA의 손상은 paraquat 농도증가에 의존적으로 증가하였다. 그러나 음극전리수를 처리한 결과 DNA의 산화적 손상이 paraquat 미처리 대조군 수준으로 거의 다 복구되었다.

• Composites Research
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• v.12 no.2
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• pp.62-69
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• 1999

During fatigue loading of composite materials, damage accumulation can be monitored by measuring their material properties. In this study, fatigue modulus is used as the damage index. Fatigue life of composite materials may be predicted analytically using damage models which are based on fatigue modulus and resultant strain. Damage models are propesed as funtions of applied stress level, number of fatigue cycle and fatigue life. The predicted life was comparable to the experimental result obtained using E-glass fiber reinforced epoxy resin materials and pultruded glass fiber reinforce polyester composites under two-stress level fatigue loading.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.493-503
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• 2009

Bridge redundancy is defined as the capability of a bridge to sustain loads after one of its main members incurs damage. It is affected by many parameters, including the number of girders, span length, girder height, internal supports, and secondary members. The present AASHTO and Korean Bridge design codes, however, define bridge redundancy only as the number of girders, and neither the evaluation method nor the required level of redundancy is given. This study presented a redundancy evaluation method for plate girder bridges with severe fatigue damage based on the reliability method,by considering the essential parameters. A required level of redundancy was also proposed as a target system reliability index from the load capacity analysis and reliability analysis of the basis bridge designed by LRFD. Finally, the level of redundancy of simple and continuous plate girder bridges with a variable number of girders designed by ASD was evaluated and presented.

• Clinical and Experimental Pediatrics
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• v.46 no.7
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• pp.687-694
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• 2003

Purpose : Regeneration and repair after ischemic renal injury appears to be modulated by circulating or locally produced growth factors. This study examined the changes of serum insulin like growth factor(IGF-I) and renal expression of IGF-I and II, vascular endothelial growth factor(VEGF), transforming growth $factor-{\beta}$($TGF-{\beta}$), and connective tissue growth factor(CTGF) during the active regeneration period after acute ischemic injury. Methods : Sera and kidney tissue samples(whole kidney, cortex, outer medullae and inner medullae) were obtained before and after one, three, five and seven days of 40 minutes bilateral renal pedicle clamping. Acute renal failure was assessed by measuring the concentration of serum creatinine. Serum IGF-I level was measured by radioimmunoassay. The mRNA expression in kidney was measured by RT-PCR. The distribution of IGF-I and CTGF was detected by immunohistochemistry. Resuts : Serum IGF-I concentration after one day following acute ischemic renal injury was significantly decreased compared to preischemic value. The mRNA levels of IGF-I, IGF-II, $TGF-{\beta}1$ and VEGF in whole kidney were temporally decreased on day one of ischemic injury. IGF-I and IGF-II expressions in outer medullae were significantly decreased on day one after ischemic injury. $TGF-{\beta}1$, CTGF and VEGF expressions were markedly decreased in medullae after one day of ischemic injury compared to other kidney sections. IGF-I was markedly decreased in cortical tubules on day one of uremic rat. CTGF was markedly increased on tubule within three days of ischemic injury. Conclusion : These findings suggest that IGFs, $TGF-{\beta}1$ and CTGF may involve in the pathogenesis or the recovery from acute ischemic renal injury.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1078-1087
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• 2020

The current study was carried out to investigate the effect of oral administration for 30 days of the Jijang kimchi extracts on prevention of diabetes, alcoholic liver injury and reduction of blood lipids in laboratory rats with alcoholic liver injury and diabetes induced by streptozotocin. In a diabetic model animals, the blood lipid profile, ALT, and AST levels were lower in kimchi extract groups compared to DC (diabetes control) group, and blood glucose level of DCJK (DC+oral administration with Jijang kimchi extracts) group was lower than that of DCCK (DC+oral administration with commercial kimchi extracts) group. Insulin levels were increased in order of NC (normal control), DCJK > DCCK > DC groups. In alcoholic liver injury model animals, ALT, AST and bilirubin were lowed in order of AC (alcohol group received 1 bottle of soju) > ACCK (1 bottle of soju plus oral administration with commercial kimchi extracts) ACJK (AC plus oral administration with Jijang kimchi extracts) > NC groups. In the clinical pathologic findings of liver tissue, AC group was severely injured, and tended to be improved in groups eating a 1 bottle of soju plus oral administration with kimchi extracts, especially Jijang kimchi extract group. The results suggest that eating Jijang kimchi can improve insulin secretion ability while lowering blood lipid profile, blood sugar and ALT, AST, and bilirubin levles in diabetic and alcoholic liver injury model animals.

• 한국노년학
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• v.30 no.3
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• pp.793-802
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• 2010

The purpose of this study was to examine the influence of extreme heat on muscle function and muscle injury marker in elderly women. The subjects of this study were eight post-menopausal elderly women without any metabolic disease. All eight subjects were asked to perform the knee joint isokinetic exercise using isokinetic equipment (cybex) in the laboratory and experimental temperature within laboratory was adjusted to two conditions: extreme heat temperature(33±0.5℃) and normal temperature(20±0.5℃) maintained in 50±3% humidity conditions. Each experimental exercise was monitored and analyzed the change of HSP70, LDH and CK. Muscular functions (peak torque, total work, percentage of peak torque body weight, fatigue index, average power and total work) were significant differences at exercise between temperatural conditions (p<.05). In extreme heat temperature, muscular injury markers (HSP70, LDH and CK) were increased, threfore resulted in significantly higher than normal temperature(p<.05). These results show that extreme heat temperature can decrease muscle function in elderly women.

• Proceedings of the Korean Nutrition Society Conference
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• 2002.05a
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• pp.128-128
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• 2002

• Korean Journal of Biological Psychiatry
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• v.2 no.2
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• pp.177-185
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• 1995

외상후 뇌손상은 대표적이며, 가장 중요한 신경정신계 질환의 하나이다. 더욱이 외상후 뇌손상 환자들은 각종의 사고 및 산업재해 등으로 인해 그 수가 급증하고 있으며, 특히 인지기능의 장애로 인한 다양한 기질성 정신장애로 고통을 겪게 된다. 따라서 외상후 뇌손상은 손상의 시점에서부터 정확하고 올바른 평가는 물론 손상후의 경과 및 치료대책의 수립에 있어서 체계적이며 종합적인 신경인지기능의 평가는 필수적이다. 왜냐하면 신경인지기능평가는 뇌의 손상부위와 이와 관련된 기능장애 및 행동의 변화에 대한 객관적인 자료를 제시해 주기 때문이다. 신경인지기능 평가의 영역은 지각, 운동기능은 물론 주요인지기능인 기억, 언어, 실행 및 감정조절능력에 이르기까지 다양하며, 외상후 뇌손상환자들은 손상부위 및 정도에 따라 신경인지기능의 장애를 초래하게 된다. 대표적인 신경인지기능평가 도구로는 KWIS, Halstead-Reitan, Luria-Nebraska batteries, 특히 전두엽기능검사인 Wisconsin Card Sorting Test (WCST)를 비롯하여, 현재는 PC/S Vienna Test System 및 Stim등의 각종 전산화 인지기능검사가 개발되어 임상에서 활발히 사용되고 있다. 즉 외상후 뇌손상환자를 위한 신경인지기능평가의 목적은 뇌손상과 관련된 신경인지기능장애를 정확히 평가하여, 환자 개개인에 적합한 인지재활치료 계획을 수립하는데 있다. 물론 여기에는 신경정신상태검사(neuropsychiatric mental status examination)를 통하여 외상 후 뇌손상의 경과 및 예후에 결정적인 영향을 미칠 수 있는 나이, 의식소실 및 외상후 기억 손상 시간의 정확한 측정은 물론 심리 사회 문화적인 상태와 두부외상전 환자의 지적수준 및 사회 적용기능이 함께 평가되어야 할 것이다.