• YAKHAK HOEJI
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• v.43 no.5
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• pp.652-658
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• 1999

To reveal the inhibitory mechanism of NO-dependent vasorelaxation by quinone derivatives (OQ1 and OQ21), we have compared the generation of free radicals by oxidative stress and the formation of cellular adducts by arylation. First, we measured oxygen consumption by quinone derivatives as a marker of oxidative stress in order to investigate whether these quinone compounds could generate reactive oxygen species. Both OQ1 and OQ21 generated free radicals and OQ21 was more potent. These results suggested that free radicals be involved in the inhibition of vasorelaxation by quinones. Next, we measured the binding capacity of quinone derivatives with intracellular GSH and protein thiols (-SH) in order to investigate whether these quinones have arylation capacity. Compared to positive control groups (menadione), both OQ1 and OQ21 depleted intracellular GSH and protein thiols very slightly. These compounds have low toxicities in mammalian tissues. From these results, we concluded that the inhibition of vasorelaxation by quinone derivatives (OQ1, OQ21) may be cuased by generation of free radicals.

• Journal of Food Hygiene and Safety
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• v.14 no.3
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• pp.282-286
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• 1999

OQ-21을 암·수 ICR계 마우스에 복강투여 하여 급성독성을 측정한 결과 최대용량 투여군에서도 사망한 동물은 관찰되지 않았다. 그리고 시험동물을 부검하여 육안 관찰한 결과 OQ-21 투여군은 대조군과 전혀 차이가 없었고 실제 독성도 비교적 낮은 것으로 판단된다. 또한 OQ-21이 혈과에 수축 반응에 영향을 미치는 지를 연구한 결과 용량 의존적으로 phenylephirne에 의한 혈관 수축을 증가시킴을 관찰하였다. 이상의 결과로부터 OQ-21은 급성독성이 약한 것으로 생각되지만 혈관 수축에 미치는 영향은 앞으로 인체 안전성에 관하여 검토하여야 할 과제로 사료된다.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.131-131
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• 2001

Two 6-(fluorinated-phenylamino)-5, 8-quinolinedione derivatives, OQ21 and OQ1, were newly synthesized as potent inhibitors of endothelial-dependent vasorelaxation. The purpose of the present study was to investigate the effect of OQ21 and OQ1 on different types of vasorelaxation and to pursue their action mechanisms. (omitted)

• YAKHAK HOEJI
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• v.49 no.4
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• pp.347-354
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• 2005

Lipopolysaccharide (LPS) induces synthesis of several inflammatory cytokines and nitric oxide (NO). NO in brain is involved not only in the regulation of important metabolic pathways via intracellular cyclic GMP-dependent path­ways, but also in neurotoxic damage by reacting with superoxide ion leading to form peroxynitrite radical. Oxidative stress has suggested to be related to the inhibition of NO synthase/cyclic GMP pathway. OQ21 is a new fluorinated quinone compound that is recently known to have inhibitory effects on both NO synthase (NOS) and guanylyl cyclase (GC). In this study, we examined effects of OQ21, other known NOS or GC inhibitors, or an antioxidant, melatonin, on the oxidative stress produced by LPS in rat brain. Oxidative stress was observed by using the 2',7'-dichlorofluorescin diacetate to measure intra-cellular reactive oxygen species (ROS) production and by measuring the formation of thiobarbituric acid reactive substances to measure lipid peroxidation. LPS induced significant increase in both ROS produdction and lipid peroxidation in all brain regions tested (striatum, hippocampus and cortex), which were dissected 6hr after intraperitoneal administration of LPS to rats. Direct striatal injection of two NOS inhibitors, N-nitro-L-arginine methyl ester and diphenyleneiodonium, or a GC inhibitor, IH-[1,2,4]oxadiazolo[4,3-a]quinoxaline-l-one, produced no significant ROS increase. However, OQ21 enhanced ROS formation in striatal tissues from LPS-treated rats. Melatonin decreased LPS-induced ROS formation and decreased ROS formation increased by OQ21 in striatum of LPS-treated rats.

• Journal of the Korean Society for Library and Information Science
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• v.58 no.2
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• pp.289-316
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• 2024

This study aimed to develop and validate a research model to investigate how the service quality of public libraries, where a 3-dimensional service quality model was applied, impacts user satisfaction and loyalty. We collected 353 valid responses through a survey targeting public library users across 21 locations, considering various regional and library-specific characteristics. Our analysis revealed that physical environment quality (PQ), interaction quality (IQ), and outcome quality (OQ) of service quality influence user satisfaction (US). Additionally, outcome quality (OQ) of service quality impacts user loyalty (UL), and user satisfaction (US) affects user loyalty (UL). We also found that quality improvement is a leading factor for user satisfaction, user satisfaction is the primary factor of user loyalty, and the perception of service quality directly and indirectly affects user satisfaction and loyalty. We concluded that continuous research should be actively conducted to respond to the evolving needs of public library users.

• The Journal of Korean society of community based occupational therapy
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• v.5 no.2
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• pp.11-21
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• 2015

Objective : We tried to know the effect on the ability of work performance, cognitive, balance, depression, ability of daily living, the quality of life, and time usage after applying the group cognitive therapy that based on lifestyle redesign to dementia elderly. Methods : We performanced the group cognitive therapy that based on lifestyle redesign to 15 dementia elderly for 12weeks by total 5 steps. We evaluated the ability of work performance(COPM), cognitive(MMSE-DS), balance(BBS), depression(GDS-K), ability of daily living(MBI), the quality of life(GQOL-D), and time usage(OQ) of before and after the programme. Results : There was a significant difference of the ability of work performance, balance, the quality of life, and locomotive area of time usage after applying the group cognitive therapy that based on lifestyle redesign to dementia elderly. Conclusion : The group cognitive therapy that based on lifestyle redesign programme is effective for satisfaction of work performance and improvement of the quality of life and balance ability. The programme is also effective for locomotive area of time usage. We found out the effect of the programme in variety of the life of dementia elderly.