• Tuberculosis and Respiratory Diseases
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• v.39 no.2
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• pp.120-130
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• 1992

Background: Although there have been many studies on the pathogenetic mechanism of acute lung injury, it is still elusive. Recently interests have been focused on the role of oxygen free radicals. But the effect of hydroxyl radical on the neutrophil mobilization and the alveolar-capillary permeability is not clear especially in the endotoxin-induced acute lung injury model of rats. This investigation was performed to evaluate the pathogenetic role of hydroxyl radical on the neutrophil accumulation into the lung and the increased alveolar-capillary permeability in the endotoxin-induced acute lung injury in rats. Method: Fifty rats were divided into four groups: vehicle control group (n=5, 6hrs; n=5, 24hrs), endotoxin-treated group (n=10, 6hrs; n=10, 24hrs), Dimethylthiourea (DMTU)-pretreated group (n=10, 6hrs), and deferoxamine (DFX)-pretreated group (n=10, 6hrs). Thirty minutes before sacrifice, $^{125}I$-tagged bovine serum albumin was injected. Six and twenty four hours after endotoxin injection, the rats were sacrificed, and the radioactivity of lung tissue and peripheral blood was counted. Permeability index was defined as the ratio of radioactivity between lung tissue and peripheral blood. Another set of rats (n=52) were divided into the same four groups as before [vehicle control group (n=5, 6hrs; n=5, 24hrs), endotoxin·treated group (n=7, 6hrs; n=8, 24hrs), DMTU-pretreated group (n=6, 6hrs; n=9, 24hrs), and DFX-pretreated group (n=5, 6hrs; n=7, 24hrs)], and were sacrificed 6 and 24 hours after endotoxin injection. In these rats, cell profile of peripheral blood and bronchoalveolar lavage fluid was evaluated, and the pathologic examination of lung tissue was performed. Results: 1) Increased alveolar-capillary permeability was observed 6 hours after endotoxin injection, which was normalized after 24 hours, and this increase was attenuated by pretreatment with DMTU and DFX. 2) Neutrophil sequestration into the lung was observed 24 hours after endotoxin administration, but this was not influenced by DMTU and DFX pretreatment. Conclusion: These results suggest that hydroxyl radical would not be involved in the sequestration of neutrophils into the lung, but plays an important role in the increase of alveolar-capillary permeability in the endotoxin-induced acute lung injury in rats.

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.319-327
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• 1994

Background: The pathogenetic mechanism of adult respiratory distress syndrome(ARDS) is not clearly defined yet, but it is well known that increased pulmonary capillary permeabilty is characteristic feature of ARDS. The increased alveolar-capillary permeability is usually preceded by damage of pulmonary artery endothelial cells. The released enzymes and oxygen free radicals from the activated neutrophils seem to play a predominant role in endothelial cell cytotoxicity. The activated neutrophils, however, probably are not the sole contributing factor in this type of damage because many cases of ARDS have been reported in severe neutropenia. Bacterial endotoxin perse and/or oxygen free radicals released from endothelial cells are suggested to be possible factors that contribute to the development of ARDS. The purpose of this study is to investigate the direct cytotoxicity of endotoxin and the role of oxygen free radicals released from the endothelial cells in endotoxin-induced endothelial cell cytotoxicity. Methods: First, to investigate whether endotoxin is cytotoxic to HUVE by itself, various doses of endotoxin were added to culture medium and cytotoxicity was measured. Second, to evaluate the possible role of oxygen free radical in endotoxin-induced HUVE cytotoxicity, various antioxidants were added on the endotoxin-induced HUVE cytotoxicity and cytotoxicity was measured. Third, to verify the release of oxygen free radicals from HUVE, the concentrations of hydrogen peroxide in the endotoxin-treated culture supernatant were measured. Finally, to observe the cytotoxic effect of hydrogen peroxide, HUVE cytotoxicity in the presence of various doses of hydrogen peroxide was measured. The fourth generations of subcultured HUVE from primary culture were used. The cell cytotoxicity was quantified by the chromium-51 release assay. Results: 1) Endotoxin alone showed HUVE cytotoxicity in a dose-dependent fashion. 2) Endotoxin-induced HUVE cytotoxicity was significantly attenuated by the pretreatment of catalase and DMTU. 3) Hydrogen peroxide was released from HUVE after endotoxin treatment in a dose-dependent fashion. 4) Exogenous hydrogen peroxide also showed HUVE cytotoxicity in a dose-dependent fashion. Conclusion: These results suggest that endotoxin alone can directly injure HUVE, and, oxygen-free radicals released from HUVE in response to endotoxin may also participate in the endotoxin-induced HUVE cytotoxicity.

• Applied Microscopy
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• v.38 no.4
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• pp.293-306
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• 2008

The essential factor of acute respiratory distress syndrome (ARDS), an acute lung injury accompanied commonly by sepsis syndrome is accumulation of neutrophils in lung tissue. The study attempted to confirm whether a lung injury would be decreased with the anti-inflammatory effect of germanium by the treated germanium prior to the development of ARDS and whether nitric oxide influence in suppressing a lung injury. Test groups were divided in the following structure for experiment; CON that has been administered with sodium chloride to airway, LPS administered with endotoxin for 5 hours in the same amount and 5 hours of endotoxin administered Ge+LPS following 1 hours of pre-treated germanium. The result of a test using experimental animals, infilteration of neutrophils (p<0.001) in bronchoalveolar lavage fluid (BALF) was significantly decreased, the structure of lung tissue was preserved relatively well, and much neutrophils with distinct positive were observed on tunel staining which showed increase of apoptotic neutrophils in the pre-treated germanium group compare to the endotoxin administrated group. In observation of ultrastructural changes of cell in BALF, phagocytic alveolar macrophage was increased in alveolar space, the nucleus of most engulfed neutrophils were condensed, and some apoptosis neutrophils appears to be DNA fragmentation and effacement of cellular organelles were found in intercellular matrix in the pre-treated germanium group. However, the nitric oxide showed increase in all the groups excluding CON, and the nitric oxide effect such as degranulation diminishing of mast cells and apoptosis increase of neutrophils in the pre-treated group only. The situation appears that there was change in internal environment of the experimental animal by the pre-treated germanium before the nitric oxide is produced and the anti-inflammatory effect activated the pre-processed germanium by nitric oxide which activated following the change. Therefore, the nitric oxide created from macrophage in accordance with the pre-treated germanium appears to influence in alleviating a lung injury. Accordingly, acute lung injury is alleviated by the anti-inflammatory effect of germanium such as inhibition of neutrophils migration, induction of neutrophil apoptosis and increase of phagocytic function of phagocyte, and the nitric oxide produced from activated macrophage by germanium would influence in suppressing a lung injury.

• The Journal of Dong Guk Oriental Medicine
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• v.8 no.1
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• pp.77-91
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• 1999

After allergic contact dermatitis elicitated by Dinitrochlorobenzene(DNCB) treatment, ICR female mice administered Yunkyopaedocksangamibang(YPGM) extract were observed to investigate the effect of YPGM on allergic contact dermatitis. This study investigated that contact hypersensitivity assay, abdominal skin morphologic changes including mast cells. At contact hypersensitivity assay, the right ear swelling in YPGM group were probability decreased than DNCB group. At observation of abdominal skin morphologic change, the infiltration of lymphocyte, lymphocyte insertion to epithelium, enlarged capillary, angiogenesis, and damages of epithelium as cytoplasmic vacuolation and enlarge of inter cellular space in YPGM were diminished than DNCB group. The number of mast cell was increased both DNCB and YPGM group. The shape of mast cell in DNCB group was mainly appeared degranulated type, but granulated type in YPGM group. The number of serotonin positive cell was increased both DNCB and YPGM group. The shape of serotonin positive cell in DNCB group was mainly appeared degranulated type, but granulated type in YPGM group. As results indicated that the YPGM extract administration work on the mitigation of skin damages in mouse with allergic contact dermatitis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1065-1075
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• 2017

In this study, high velocity impact tests along with modeling of material behavior and numerical analyses were conducted to predict the dispersion behavior of the debris resulting from a high velocity impact fracture. For the impact tests, two different materials were employed for both the projectile and the target plate - the first setup employed aluminum alloy while the second employed steel. The projectile impacts the target plate with a velocity of approximately 1 km/s were enforced to generate the impact damages in the aluminum witness plate through the fracture debris. It was confirmed that, depending on the material employed, the debris dispersion behavior as well as the dispersion radii on the witness plate varied. A numerical analysis was conducted for the same impact test conditions. The smoothed particle hydrodynamics (SPH)-finite element (FE) coupled technique was then applied to model the fracture and damage upon the debris. The experimental and numerical results for the diameters of the perforation holes in the target plate and the debris dispersion radii on the witness plate were in agreement within a 5％ error. In addition, the impact test using steel was found to be more threatening as proven by the larger debris dispersion radius.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.2
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• pp.169-180
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• 2022

Streptococcus sp. is generally known as a strain that produces hyaluronic acid. In this study, we focused on ingredients other than hyaluronic acid among several metabolites produced by Streptococcus sp. during cultivation. The hair experimental sample (HAIRCLE^TM) was prepared with Streptococcus sp. culture filtrate under the condition that hyaluronic acid was not produced and the effect on the hair was identified. Tensile strength of hair was tested with a universal testing machine (UTM). Surface properties of a hair were examined with an atomic force microscope (AFM). Our results suggest that HAIRCLE^TM could prevent damage to a hair such as destroyed-cuticle, increased-faction force, and broken-hair. Furthermore, hair-related experiments confirmed that HAIRCLE^TM could promote the expression of hair growth factors VEGF, HGF, and Wnt10b and mitigate male hair loss by inhibiting androgen receptors and TGF-β2 expression. In addition, it was confirmed that the expression of barrier-related factors (INV, CLDN-1) was increased for oxidative stress, and the COX-2 expression, an inflammatory factor, was inhibited, thereby improving damaged scalp barriers and alleviating induced inflammation.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.103-112
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• 2008

In the feasibility analysis, Braess' Paradox results in the negative social benefit in spite of adding transportation facilities. Consequently, it has been difficult to judge on the investment of SOC projects. This research aims to analyze the Braess' Paradox in the feasibility analysis and to seek a remedy for the Paradox. Several experiments were conducted on the simple network under the various conditions. From the experiments, following findings were validated: Braess' Paradox occurred only if travel demands met within certain intermediate range. In terms of traffic assignment method, the SO was more likely to reduce the effect of the Braess' Paradox than the UE. However, the Braess' Paradox in the benefit of operating cost saving occurred in all cases and the paradox in the total benefit continued. In order to solve the problem, new link cost function considered travel time and operating cost simultaneously were suggested. As a result, the negative benefit was significantly decreased in the UE case and total negative benefit was no longer shown in the SO case through the analysis.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.395-402
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• 2016

When the operation of battery is converted at charging and discharging system based on a DC micro grid, the voltage is fluctuated. And excessive voltage fluctuation could cause damage or failure of charging and discharging equipment. Therefore, in this paper, we studied the operating schedule of the charging and discharging system based on the DC micro grid and a design point of the capacitor which was able to reduce the voltage fluctuation. A result of computer simulation showed that when a fluctuation-reducing capacitor which had an initial value of 600V/35mF was applied at the charging and discharging system based on a DC micro grid which was operated with three charging battery sets and five discharging battery sets, voltage fluctuation by charging and discharging operation was reduced by about 63.3%. Furthermore, voltage fluctuation which occurred when initial network voltage was stabilized was reduced by about 73%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.457-467
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• 2016

In this study, we investigate the dispersion behavior of debris and debris cloud generated by high-velocity impacts using the smoothed particle hydrodynamics (SPH) technique. The projectile and target plate were made of aluminum, and we confirm the validity of the SPH technique by comparing the measured major and minor axis lengths of the debris cloud in the reference with the predicted values obtained through the SPH analysis. We perform high-velocity impact and fracture analysis based on the verified SPH technique within the velocity ranges of 1.5~4 km/s, and we evaluate the dispersion behavior of debris induced by the impact in terms of its kinetic energy. The maximum dispersion radius of the debris on the witness plates located behind the target plate was increased with increasing impact velocity. We derive an empirical equation that is capable of predicting the dispersion radius, and we found that 95％ of the total kinetic energy of the debris was concentrated within 50％ of the maximum dispersion radius.

• Korean Journal of Social Welfare
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• v.61 no.1
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• pp.359-382
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• 2009

Little research has been done to understand the dynamics of well-being among the oldest old, although Korea experiences a rapid increase of this population group. This study explored the effects of demographic characteristics, physical condition, stressful life events and worries on life satisfaction of aged 85 and over. The moderating effects of psychosocial resources in buffering the negative effects of the life events and worries on life satisfaction of this group were also examined. The survey data collected from 213 community residing aged 85 and over was used for analyses. Major findings are as follows. First, most frequent stressors of the oldest old were health related problems. Second, greater worries, higher income status, lower level of physical impairment, co-residence with adult children were significantly related to higher life satisfaction of the oldest old. Third, emotional support from adult children as well as self-esteem of the older persons had buffering effects on the relationship between worries and life satisfaction. According to the results, implications for practice and services to increase life satisfaction of the oldest old were discussed.