• Advances in Traditional Medicine
• /
• v.6 no.1
• /
• pp.53-57
• /
• 2006

The plant Indigofera aspalathoides is used by a large number of tribes in India for the treatment of various hepatic disorders and abscesses. The methanol extract of Indigofera aspalathoides (MEIA) was evaluated for its protective effects on gastric mucosal lesion in Wister albino rats against indomethacin, histamine and ethanol induced gastric mucosal damage. The response to MEIA was assessed using the ulcer index, thiobarbituric acid reactive substance (TBARS), and glutahione level. MEIA pretreatment showed protection against chemical induced gastric mucosal damage, a significant reduction in the ulcer index and TBARS activity and increase glutathione level as compared with that of standard drugs.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.903-907
• /
• 1996

Under two level block loading, the carbornitrizing specimen can be expected to show different behavior from other uniform material because the properties of surface layer and inner material are different from each other. In this research, the modified Marco-Starkey cumulative theory, which considers load interaction effect, can predict the life of SCM415 carbornitrizing and original notched and smooth specimen, In the low-high test of carbornitrizing specimen which has long life, however, we may additionally consider the increase of life by means of the stress hardening of inner original material.

• Tunnel and Underground Space
• /
• v.9 no.1
• /
• pp.72-77
• /
• 1999

New criteria to evaluate blasting damage to structure is proposed considering environmental caused daily deformation of cracks in structures. Results from 3 brick houses in fishing village shows that more than 10 times higher vibration level than design criteria of 0.5 kine is required to cause structural damage.

• Journal of Environmental Health Sciences
• /
• v.23 no.4
• /
• pp.9-15
• /
• 1997

This experiment was carried out to examine the roles of selenium in arsenic- and chromium-induced oxidative stress, which results in chromosomal damage, such as sister chromatid exchange (SCE) and chromosomal aberration (CA). For this purpose, the frequency of CA and SCE related to the level of 0xidative stress were analyzed. Selenium decreased the frequency of CA induced by As. In order to evaluate the effect of selenium on clastogenic factors, media from As- and Cr-treated cells were ultrafiltered and added again to cells in the presence or absence of selenium. Selenium decreased the frequency of SCE by As and Cr. This observation indicates the possibility of presence of clastogenic factor. In addition, the clastogenic factor would be involed in oxidative stress since selenium decreased the level of oxidative stress. Thus, it is suggested that selenium may play a role as an anti-clastogenic effector by preventing the oxidative stress, thereby decreasing the frequency of Asand Cr-induced chromosomal damage.

• Journal of Life Science
• /
• v.17 no.7 s.87
• /
• pp.956-963
• /
• 2007

The purpose of the present study was to examine the effects of iron shot practice volume based on golf skill level on the indices of muscle damage and fatigue in blood. Twenty four golf players were studied under conditions of different golf skill level (beginners, intermediate, expert) and practice volume (100, 200, 300balls). In this study blood CK and LDH were determined to show the level of muscle damage, and blood phosphorus, lactate, and ammonia were measured to see the level of fatigue. Blood creatinine, and IGF- I generally used to see the rate of protein synthesis were also measured. In summary, these results are interpreted to mean that 1) blood fatigue factors, muscle damages, and creatinine levels increased due to a rise in the practice volume of iron shot, 2) those levels decreased due to rise in the golf skill level, 3) blood fators and creatinine recovered quickly after exercise, however muscle damages did not recover even after 24hr, Therefore, both golf skill lev-el and practice volume should be considered to prevent muscle damage and fatigue during practice iron shot.

• Earthquakes and Structures
• /
• v.6 no.6
• /
• pp.581-609
• /
• 2014

Reinforced concrete (RC) structures are likely to experience damage when subjected to earthquakes. Damage index (DI) has been recognised as an advanced tool of quantitatively expressing the extent of damage in such structures. Last 30 years have seen many concepts for DI proposed in order to calibrate the observed levels of damage. The current research briefly reviews all available concepts and investigates their relative merits and limitations with a view to proposing a new concept based on residual deformation. Currently available DIs are classified into two broad categories - non-cumulative DI and cumulative DI. Non-cumulative DIs do not include the effects of cyclic loading, whilst the cumulative concepts produce more rational indication of the level of damage in case of earthquake excitations. Ideally, a DI should vary within a scale of 0 to 1 with 0 representing the state of elastic response, and 1 referring to the state of total collapse. Some of the available DIs do not satisfy these criteria. A new DI based on energy is proposed herein and its performances, both for static and for cyclic loadings, are compared with those obtained using the most widely accepted DI in literature. The proposed DI demonstrates a rational way to predict the extent of damage for a number of case studies. More research is encouraged to address some identified issues.

• Structural Monitoring and Maintenance
• /
• v.4 no.3
• /
• pp.221-236
• /
• 2017

In this study, the feasibility of vibration-based damage alarming algorithms are numerically evaluated for wind turbine tower structures which are subjected to harmonic force excitation. Firstly, the algorithm of vibration-based damage alarming for the wind turbine tower (WTT) is visited. The natural frequency change, modal assurance criterion (MAC) and frequency-response-ratio assurance criterion (FRRAC) are utilized to recognize changes in dynamic characteristics due to a structural damage. Secondly, a finite element model based on a real wind turbine tower is established in a structural analysis program, Midas FEA. The harmonic force is applied at the rotor level as presence of excitation. Several structural damage scenarios are numerically simulated in segmental joints of the wind turbine model. Finally, the natural frequency change, MAC and FRRAC algorithm are employed to identify the structural damage occurred in the finite element model. The results show that these criteria could be used as promising damage existence indicators for the damage alarming in wind turbine supporting structures.

• Smart Structures and Systems
• /
• v.15 no.5
• /
• pp.1215-1232
• /
• 2015

In the present paper, a method for identifying damage in a multi storeyed shear building structure is presented using minimum number of modal parameters of the structure. A damage at any level of the structure may lead to a major failure if the damage is not attended at appropriate time. Hence an early detection of damage is essential. The proposed identification methodology requires experimentally determined sparse modal data of any particular mode as input to detect the location and extent of damage in the structure. Here, the first natural frequency and corresponding partial mode shape values are used as input to the model and results are compared by changing the sensor placement locations at different floors to conclude the best location of sensors for accurate damage identification. Initially experimental data are simulated numerically by solving eigen value problem of the damaged structure with inclusion of random noise on the vibration characteristics. Reliability of the procedure has been demonstrated through a few examples of multi storeyed shear structure with different damage scenarios and various noise levels. Validation of the methodology has also been done using dynamic data obtained through experiment conducted on a laboratory scale steel structure.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2001.05a
• /
• pp.116-116
• /
• 2001

The alkaline Comet assay has been used with increasing popularity to investigate the level of DNA damage in terms of strand breaks and alkaline labile sites in biomonitoring studies within the last decade in western countries.(omitted)

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.15 no.4
• /
• pp.26-32
• /
• 1978

For a long life photovoltaic cell the degradation of the device characteristics with 1 MeV electron radiation must be known so as to be able to predict the life of the cell. Hence, a study was made of radiation damage effects on the bulk properties of the silicon crystal. From the results of the data, it is concluded that there appeared to be a steads rotate damage level reached in f type material.