• Composites Research
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• v.12 no.4
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• pp.71-78
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• 1999

To determine the effect of chemical structure of linear amine curing agents on thermal and mechanical properties, standard epoxy resin DGEBA was cured with diaminodiphenyl methane (DDM), diaminodiphenyl sulphone (DDS) in a stoichiometrically equivalent ratio. From this work, the effect of aromatic amine curing agents. In contrast, the results show that the DGEBA/DDS cure system having the sulfone structure between the benzene rings had higher values in the conversion of epoxide, density, shrinkage (%), glass transition temperature, tensile modulus and strength, flexural modulus and strength than the DGEBA/DDM cure system having methylene structure between the benzene rings, whereas the DGEBA/DDM cure system presented higher values in the maximum exothermic temperature, thermal expansion coefficient, and thermal stability. These results are caused by the relative effects of sulfone group having strong electronegativity and methylene group having (+) repulsive property and stem from the effect of the conversion ratio of epoxide group. The result of fractography shows that the each grain size of the DDM/DGEBA system with feather-like structure is larger than that of the DDS/DGEBA system.

• Reproductive and Developmental Biology
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• v.36 no.3
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• pp.147-154
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• 2012

This study was designed to determine whether low-density lipoproteins (LDL) from egg yolk and taurine, hypotaurine and trehalose as antioxidant in extender improve the freezability and fertility of Korean Jeju Black Bull semen. The semen was cryopreserved with tris egg yolk extenders containing 7% glycerol and treated 4% LDL, 20 mM taurine, hypotaurine and trehalose. Frozen-thawed sperm were evaluated motility, viability, membrane, and acrosome integrity and sperm penetration ability. The results were compared to semen cryopreserved in tris egg yolk extender only as control. Frozen-thawed semen evaluation cleary indicated that the addition of LDL and LDL-antioxidants (taurine, hypotaurine and trehalose) combination were significantly improved (p<0.05) the viability (%; with staining test using eosin-Y) compared to control spermatozoa. Also, in membrane integrity (%; with supravital hypo-osmotic swelling test), not only LDL-antioxiants combination but also LDL were significantly increased (p<0.05) the swelled sperm using HOST compared to control. Sperm acrosome integrity state was classified by CTC (chlortetracycline) staining test. F pattern was significantly increased in LDL-antioxidant combination than control (p<0.05) and B pattern was not significantly differences among all treatments and control. However, AR pattern was significantly decreased in LDL-antioxidants combination than control (p<0.05). Pronucleus formation and sperm penetration index (SFI) were significantly increased in LDL and LDL-antioxidants combination than control (p<0.05). Especially, LDL-taurine significantly improved pronucleus fomation and SFI than LDL (p<0.05). It was concluded that LDL and LDL-antioxidants in extender improved the freezability and fertility of Korean Jeju Black bull spermatozoa.

• Korean Journal of Environment and Ecology
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• v.31 no.3
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• pp.337-343
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• 2017

This study is going to contribute the activation of ecosystem services written in the 3rd National Basic Plan for Nature Conservation(2016~2025) in Korea. Meanwhile we considered the benefits that the nature has given to the humankind as free goods or services which we may consume traditionally without due payment therefore. But on account of the expansion of cities and expedition of development, as the carrying capacity of the nature has been breached, people have come to try to restore and enhance artificially such vulnerable capacity. It is necessary to compensate the opportunity cost which the land owners or occupiers have to pay for conservation and maintenance of natural capitals which yield the ecosystem services. Therefore the institutionalization of ecosystem services should be established that the consumers who enjoy such services should share the interest from enjoying services with the land owners or occupiers who produce the ecosystem services, under the legal system which will make it possible to connect the benefit sharing with the conservation of environment. However it is the first task that the present legal system could not realize the fair and equitable benefit sharing between the producers and consumers of ecosystem services. And the second task in such legal system is that the value of ecosystem services could not be fully considered in the process of development planning. According to the analysis of this study, the institutionalization of ecosystem services in the government side and the civilian side could be realized to somewhat extent, although not sufficient. Especially the transactions of ecosystem services through the private contract among stakeholder are possible in the course of development planning or without any relevancy to a development project. The final task in the institutionalization of ecosystem services is how to assess the ecosystem services and to value the economic benefits therefrom on the basis of what kinds of procedures relating to some development processes. To overcome such difficulties, it is necessary that the state, trend and change of ecosystem services confronting with a developing project should be assessed concretely at the threshold of development. It is possible to integrate the ecosystem services into the environmental impact assessment(IEA), not by way of the Act of IEA, but by way of the Decree thereof.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.292-296
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• 2007

Background: This retrospective study was undertaken to assess the effectiveness of the 8-French (Fr) catheter ($Pleuracan^{(R)}$) for the initial treatment of primary spontaneous pneumothorax. Material and Method: Between July 2004 and July 2006, 59 patients (72 cases) underwent a closed thoracostomy for primary spontaneous pneumothorax. We divided these patients into two groups: group T (large bore (>20 Fr) chest tube group) and group P ($Pleuracan^{(R)}$ group). Result: Initially, the $Pleuracan^{(R)}$ catheters were inserted in 41 cases. There were four catheter malfunctions (9.8%) : three cases had a subsequent closed thoracostomy with a large bore chest tube. Ultimately, there were 34 cases in group T and 38 cases in group P. There were no significant differences in indwelling catheter time ($T:\;2.1{\pm}1.5\;days,\;P:\;2.1{\pm}1.3\;days$), hospital stay ($T:\;6.4{\pm}5.4\;days,\;P:\;5.2{\pm}2.9\;days$) and complications (T: 3%, P: 0%) between the two groups. The percentage of cases that needed intravenous analgesics in group P was 60% (23/38); this was significantly lower than the number for group T (90%, 31/34) (p=0.003). In a subgroup of patients that did not undergo bullectomy(T: 17 cases, P: 19 cases), there were no significant differences in the duration of air leakage ($T:\;0.5{\pm}0.7\;days,\;P:\;0.5{\pm}1.2\;days$) and in the percentage of patients with complete lung re-expansion (T: 94%, P: 84%) between the two groups. Conclusion: Application of the $Pleuracan^{(R)}$ catheter for the initial treatment of primary spontaneous pneumothorax was as effective as the large bore chest tube.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.13-24
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• 2006

Neuronal apoptotic events, consequently resulting in neuronal cell death, are occurred in hypoxic/ischemic condition. This cell death has been shown to be accompanied with the production of reactive oxygen species (ROS), which can attack cellular components such as nucleic acids, proteins and phospholipid. However, the underlying mechanisms of apoptosis induced in hypoxic/ischemic condition and its treatment methods are unsettled. Cobalt chloride $(CoCl_2)$ has been known to mimic hypoxic condition including the production of ROS. Epigallocatechin gallate (EGCG), a green tea polyphenol, has diverse pharmacologial activities in cell growth and death. This study was aimed to investigate the apoptotic mechanism by $CoCL_2$ and effects of EGCG on $CoCl_2-induced$ apoptosis in PC12 cells. Administration of $CoCl_2$ decreased cell survival in dose- and time-dependent manners and induced genomic DNA fragmentation. Treatment with $100{\mu}M$ EGCG for 30 min before PC12 cells were exposed to $150{\mu}M$ $CoCl_2$, being resulted in the cell viability and DNA fragmentation being rescued. $CoCl_2$ caused morphologic changes such as cell swelling and condensed nuclei whereas EGCG attenuated morphologic changes by $CoCl_2$. EGCG suppressed the apoptotic peak and a loss of ${\Delta}{\psi}_m$ induced by $CoCl_2$. $CoCl_2$ decreased Bcl-2 expression but Bax expression was not changed in $CoCl_2$- treated cells. EGCG attenuated the Bcl-2 underexpression by $CoCl_2$. $CoCl_2$ augumented the cytochrome c release from mitochondria into cytoplasm and increased caspase-8, -9 and caspase-3 activity a marker of the apoptotic executing stage. EGCG ameliorated the incruement in caspase-8, -9 and -3 activity, and cytochrome c release by $CoCl_2$ NAC (N-acetyl-cysteine), a scavenger of ROS, attenuated $CoCl_2-induced$ apoptosis in consistent with those of EGCG. These results suggest that $CoCl_2$ induces apoptotic cell death through both mitochondria- and death receptor-dependent pathway and EGCG has neuroprotective effects against $CoCl_2-induced$ apoptosis in PC12 cells.