• Journal of Embryo Transfer
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• v.31 no.4
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• pp.355-365
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• 2016

The cryopreservation of sperm has become the subject of research for successful artificial insemination technologies. Antifreeze proteins (AFPs), one of the factors necessary for effective cryopreservation, are derived from certain Antarctic organisms. These proteins decrease the freezing point of water within these organisms to below the temperature of the surrounding seawater to protect the organism from cold shock. Accordingly, a recent study found that AFPs can increase the motility and viability of spermatozoa during cryopreservation. To evaluate this relationship, we performed cryopreservation of boar sperm with AFPs produced in the Arctic yeast Leucosporidium sp. AFP expression system at four concentrations (0, 0.01, 0.1, and $1{\mu}g/ml$) and evaluated motility using computer assisted sperm analysis. DNA damage to boar spermatozoa was measured by the comet assay, and sperm membrane integrity and acrosome integrity were evaluated by flow cytometry. The results showed that motility was positively affected by the addition of AFP at each concentration except $1{\mu}g/ml$ (p<0.001). Although cryopreservation with AFP decreased the viability of the boar sperm using, the tail DNA analyses showed that there was no significant difference between the control and the addition of 0.1 or $0.01{\mu}g/ml$ AFP. In addition, the percentage of live sperm with intact acrosomes showed the least significant difference between the control and $0.1{\mu}g/ml$ AFP (p<0.05), but increased with $1{\mu}g/ml$ AFP (p<0.001). Our results indicate that the addition of AFP during boar sperm cryopreservation can improve viability and acrosome integrity after thawing.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.43-54
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• 2005

This paper presents cost-effectiveness evaluation of semi-active control system for cable-stayed bridge under earthquake excitations with various magnitudes and frequency contents. Semi-active control system, which is operated by using Bi-stale control method on the basis of linear quadratic Gaussian (LQG) optimal controller, is designed for the benchmark control problem proposed by Dyke et at. The cost-effectiveness of the proposed control system is defined by the ratio of life-cycle costs between a bridge structure with shock transmission units and a bridge structure with the semi-active control devices. The simulated results show that the damper cost has little influence on the cost-effectiveness of the semi-active control system while the cost-effectiveness is quite sensitive to the damage cost induced by the bridge failure. It is also found that the semi-active control system guarantees relatively high cost-effectiveness for the cable-stayed bridge subject to the ground motions in the regions of moderate seismicity with soft soil condition and strong seismicity with stiff soil condition.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.879-890
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• 2006

Background: The dysfunction of multiple organs is found to be caused by reactive oxygen species as a major modulator of microvascular injury after hemorrhagic shock. Hemorrhagic shock, one of many causes inducing acute lung injury, is associated with increase in alveolocapillary permeability and characterized by edema, neutrophil infiltration, and hemorrhage in the interstitial and alveolar space. Aggressive and rapid fluid resuscitation potentially might increased the risk of pulmonary dysfunction by the interstitial edema. Therefore, in order to improve the pulmonary dysfunction induced by hemorrhagic shock, the present study was attempted to investigate how to reduce the inflammatory responses and edema in lung. Material and Method: Male Sprague-Dawley rats, weight 300 to 350 gm were anesthetized with ketamine(7 mg/kg) intramuscular Hemorrhagic Shock(HS) was induced by withdrawal of 3 mL/100 g over 10 min. through right jugular vein. Mean arterial pressure was then maintained at $35{\sim}40$ mmHg by further blood withdrawal. At 60 min. after HS, the shed blood and Ringer's solution or 5% albumin was infused to restore mean carotid arterial pressure over 80 mmHg. Rats were divided into three groups according to rectal temperature level($37^{\circ}C$[normothermia] vs $33^{\circ}C$[mild hypothermia]) and resuscitation fluid(lactate Ringer's solution vs 5% albumin solution). Group I consisted of rats with the normothermia and lactate Ringer's solution infusion. Group II consisted of rats with the systemic hypothermia and lactate Ringer's solution infusion. Group III consisted of rats with the systemic hypothermia and 5% albumin solution infusion. Hemodynamic parameters(heart rate, mean carotid arterial pressure), metabolism, and pulmonary tissue damage were observed for 4 hours. Result: In all experimental groups including 6 rats in group I, totally 26 rats were alive in 3rd stage. However, bleeding volume of group I in first stage was $3.2{\pm}0.5$ mL/100 g less than those of group II($3.9{\pm}0.8$ mL/100 g) and group III($4.1{\pm}0.7$ mL/100 g). Fluid volume infused in 2nd stage was $28.6{\pm}6.0$ mL(group I), $20.6{\pm}4.0$ mL(group II) and $14.7{\pm}2.7$ mL(group III), retrospectively in which there was statistically a significance between all groups(p<0.05). Plasma potassium level was markedly elevated in comparison with other groups(II and III), whereas glucose level was obviously reduced in 2nd stage of group I. Level of interleukine-8 in group I was obviously higher than that of group II or III(p<0.05). They were $1.834{\pm}437$ pg/mL(group I), $1,006{\pm}532$ pg/mL(group II), and $764{\pm}302$ pg/mL(group III), retrospectively. In histologic score, the score of group III($1.6{\pm}0.6$) was significantly lower than that of group I($2.8{\pm}1.2$)(p<0.05). Conclusion: In pressure-controlled hemorrhagic shock model, it is suggested that hypothermia might inhibit the direct damage of ischemic tissue through reduction of basic metabolic rate in shock state compared to normothermia. It seems that hypothermia should be benefit to recovery pulmonary function by reducing replaced fluid volume, inhibiting anti-inflammatory agent(IL-8) and leukocyte infiltration in state of ischemia-reperfusion injury. However, if is considered that other changes in pulmonary damage and inflammatory responses might induce by not only kinds of fluid solutions but also hypothermia, and that the detailed evaluation should be study.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.157-168
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• 2018

Recently, the occurrence of typhoons and heavy rainfall is increasing due to climate change. This causes increase in possibility of landslide damages in rural areas. However, in reality, the precise engineering stability assessment studies are still insufficient. Therefore, in order to reduce the landslide damages and effectively manage mountainous areas, the development of disaster prevention techniques is needed. In this study, to analyze the shock absorbing effect of the buffer-spring during application of dynamic impact load in the debris flow protection system, numerical analysis is carried out for each free field of the buffer-spring and the load sharing ratio of the buffer-spring is also examined. In addition, the field applicability is verified by comparison of the tensile strength of the conventional buffer-spring and the wedge type buffer-spring on various magnitudes of dynamic impact load. As a result of the study, it is found that the net-type debris protection system is effective to mitigate loss of properties and human lifes during landslide.

• Geomechanics and Engineering
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• v.13 no.2
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• pp.333-352
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• 2017

A comparison study is made between the dynamic properties of an argillaceous siltstone and its grouting-reinforced body. The purpose is to investigate how grout injection can help repair broken soft rocks. A slightly weathered argillaceous siltstone is selected, and part of the siltstone is mechanically crushed and cemented with Portland cement to simulate the grouting-reinforced body. Core specimens with the size of $50mm{\times}38mm$ are prepared from the original rock and the grouting-reinforced body. Impact tests on these samples are then carried out using a Split Hopkinson Pressure Bar (SHPB) apparatus. Failure patterns are analyzed and geotechnical parameters of the specimens are estimated. Based on the experimental results, for the grouting-reinforced body, its shock resistance is poorer than that of the original rock, and most cracks happen in the cementation boundaries between the cement mortar and the original rock particles. It was observed that the grouting-reinforced body ends up with more fragmented residues, most of them have larger fractal dimensions, and its dynamic strength is generally lower. The mass ratio of broken rocks to cement has a significant effect on its dynamic properties and there is an optimal ratio that the maximum dynamic peak strength can be achieved. The dynamic strain-softening behavior of the grouting-reinforced body is more significant compared with that of the original rock. Both the time dependent damage model and the modified overstress damage model are equally applicable to the original rock, but the former performs much better compared with the latter for the grouting-reinforced body. In addition, it was also shown that water content and impact velocity both have significant effect on dynamic properties of the original rock and its grouting-reinforced body. Higher water content leads to more small broken rock pieces, larger fractal dimensions, lower dynamic peak strength and smaller elastic modulus. However, the water content plays a minor role in fractal dimensions when the impact velocity is beyond a certain value. Higher impact loading rate leads to higher degree of fragmentation and larger fractal dimensions both in argillaceous siltstone and its grouting-reinforced body. These results provide a sound basis for the quantitative evaluation on how cement grouting can contribute to the repair of broken soft rocks.

• Journal of Trauma and Injury
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• v.24 no.2
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• pp.105-110
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• 2011

Purpose: Chest injuries in multiple trauma patients are major predisposing factor for increased length of stay in intensive care unit, prolonged mechanical ventilator, and respiratory complications such as pneumonia. The aim of this study is the evaluation of lung injury score as a risk factor for prolonged management in intensive care unit (ICU). Methods: Between June to August in 2011, 46 patients admitted to shock and trauma center in our hospital and 24 patients had associated chest damage without traumatic brain injury. Retrospectively, we calculated injury severity score (ISS), lung injury score, and the number of fractured ribs and performed nonparametric correlation analysis with length of stay in ICU and mechanical ventilator support. Results: Calculated lung injury score(<48 hours) was median 1(0-3) and ISS was median 30(8-38) in study population. They had median 2(0-14) fractured ribs. There were 2 bilateral fractures and 2 flail chest. Ventilator support was needed in 11(45.8%) of them for median 39 hours(6-166). The ISS of ventilator support group was median 34(24-34) and lung injury score was median 1.7(1.3-2.5). Tracheostomy was performed in one patient and it was only complicated case and ICU stay days was median 9(4-16). In correlation analysis, Lung injury score and ISS were significant with the length of stay in ICU but the number of fractured ribs and lung injury score were predicting factors for prolonged mechanical ventilator support. Conclusion: Lung injury score could be a possible prognostic factor for the prediction of increased length of stay in ICU and need for mechanical ventilator support.