• 한국의류학회지
• /
• 제32권11호
• /
• pp.1760-1770
• /
• 2008

The purpose of this study was 1) to find effects of private Guanxi and organizational relationship on quality of organizational relationship, 2) to find effects of private Guanxi and organizational relationship on performance of distribution channel, and 3) to also find effects of quality of organizational relationship on performance of distribution channel. Apparel manufacturers and distributors in China participated in the study. Random sampling method was used to collect the data. Data from 173 questionnaires were used for the statistical analysis. Factor analysis, Cronbach's alpha coefficient, and regression analysis was conducted. Two factors of private Guanxi were classified(i.e., affective Guanxi, instrumental Guanxi). Three factors of organizational relationship type were identified(i.e., opportunistic relationship, cooperative relationship, vertical relationship). The result indicated that affective Guanxi in terms of private Guanxi positively affected on quality of organizational relationship. Cooperative relationship and vertical relationship in terms of organizational relationship positively affected on quality of organizational relationship. Affective Guanxi positively affected on non-financial performance and financial performance in terms of performance of distribution channel. Instrumental Guanxi in terms of private Guanxi positively affected on financial performance only. Cooperative relationship in terms of organizational relationship positively affected on non-financial performance and vertical relationship positively affected on financial performance. Quality of organizational relationship positively affected on non-financial performance and vertical relationship positively affected on financial performance.

• Biomolecules & Therapeutics
• /
• 제4권4호
• /
• pp.373-377
• /
• 1996

The effect of potassium channel openers, KR-30450, KR-30818 and lemakalim have been compared against several spasmogens in guinea pig bronchi. In guinea pig bronchi, KR-30450 had a greater relaxant effect than lemakalim and KR-30818 against tone induced by histamine $10^{-5}M$ ($EC_{50}$ $\mu$M: KR-30450, 0.108$\pm$0.077; KR-30818, 0.403$\pm$0.023; lemakalim, 0.968$\pm$0.036) and prostaglandin $F_{2\alpha} 3\times10^{-6} M$ ($EC_{50}$ $\mu$M: KR-30450, 0.018$\pm$0.001; KR-30818, 0.028$\pm$0.003; lemakalim, 0.138$\pm$0.019). Relaxant effect of KR-30450 and KR-30818 were significantly reduced by 20 min pretreatment of tissues with $10^[-6}$ M glibenclamide, a selective blocker of ATP-sensitive potassium channel. Against acetylcholine-induced tone in guinea pig bronchi, however, these compounds had little effect. In summary, KR-30450 and KR-30818 showed greater relaxant effect than lemakalim in guinea pig bronchi (KR-30450>KR-30818>lemakalim). These relaxant actions are suggested to be mediated at least in part by a mechanism which involves the opening of ATP-sensitive potassium channel.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 2003년도 정기총회 및 학술발표회
• /
• pp.43-43
• /
• 2003

Large-conductance $Ca^{2+}$-actived $K^{+}$ channels ($BK_{Ca}$ channels) play a key role in setting the pace of contractile activity in muscle and are involved in the regulation of neurotransmitter release in neuron. $BK_{Ca}$ channels are activated by depolarizing membrane potential and the elevated level of intracellular calcium. Using yeast-two hybrid assay, we have identified a novel protein interacting with the cytosolic carboxyl terminus of rSlo, the brain isoform of rat large-conductance $Ca^{2+}$-activated $K^{+}$ channel $\alpha$-subunit. The novel gene encodes 51 kDa protein and is named as SIRK(rSlo-interacting RGS-like protein). SIRK is expressed in various tissues and localized in the cytosolic and the membrane fraction. Biochemical and immunological studies indicated that SIRK physically interacted with the cytosolic region of rSlo. To investigate whether SIRK can modulate the activity of rSlo, GFP-fused SIRK and rSlo were transiently transfected into COS-7 cells and the effects of SIRK was studied using electrophysiological means. We concluded that the overexpression of SIRK alters the surface expression of rSlo channel with only a limited effect on the biophysical characteristics of the channel.the channel.

• 대한수의학회지
• /
• 제37권2호
• /
• pp.331-338
• /
• 1997

최근 동물의 진통 및 진정을 목적으로 널리 사용되고 있는 imidazole 유도체인 clonidine, medetomidine, etomidate 등의 약물과 xylazine의 효과를 발정정지기의 척출 돼지 자궁근에서 검토하였다. Clonidine($10^{-8}{\sim}10^{-6}M$)이나 medetomidine($10^{-8}{\sim}10^{-6}M$)은 xylazine과 비슷한 정도로 용량의존적인 자궁근의 수축을 일으켰다. Clonidine, medetomidine, xylazine 등의 $EC_{50}$는 각각 24.7nM, 19.9nM, 45.1nM이었다. 그러나 etomidate는 $10^{-6}M$ 미만의 농도에서 반응이 거의 없었으며, $10^{-6}M$ 이상에서 수축반응을 일으켰다. 이들 agonists의 효과는 yohimbine($10^{-8}{\sim}10^{-6}M$), idazoxan($10^{-7}{\sim}10^{-5}M$), tolazoline($10^{-7}{\sim}10^{-5}M$) 등의 ${\alpha}_2-adrenoceptor$ antagonists에 의해서 차단되었으나, ${\alpha}_1-adrenoceptor$ antagonist인 prazosin ($10^{-6}M$)에 의해서는 차단되지 않았다. 또한 $Ca^{2+}-free$ medium이나 verapamil($10^{-5}M$)의 전처치에 의해서 이들 agonist의 효과가 완전히 차단되었다. 결론적으로 발정정지기의 돼지 자궁근에서 clonidine, medetomidine, etomidate, xylazine 등은 ${\alpha}_2-adrenoceptors$의 흥분을 통해 자궁근의 수축을 일으키며, 이 효과는 voltage-dependent $Ca^{2+}$ channels을 통한 extracellular $Ca^{2+}$ influx의 증가에 의한 것으로 추론하였다.

• Journal of Korean Neurosurgical Society
• /
• 제41권1호
• /
• pp.30-38
• /
• 2007

Objective : To elucidate the role of aquaporin-4[AQP4] in cerebral edema formation, we studied the expression and subcellular localization of AQP4 in astrocytes after focal cerebral ischemia. Methods : Cerebral ischemia were induced by permanent middle cerebral artery[MCA] occlusion in rats and estimated by the discoloration after triphenyltetrazolium chloride[TTC] immersion. Change of AQP4 expression were evaluated using western blot. Localization of AQP4 was assessed by confocal microscopy and its interaction with ${\alpha}-syntrophin$ was analyzed by immunoprecipitation. Results : After right MCA occlusion, the size of infarct and number of apoptotic cells increased with time. The ratio of GluR1/GluR2 expression also increased during ischemia. The polarized localization of AQP4 in the endfeet of astrocytes contacting with ventricles, vessels and pia mater was changed into the diffuse distribution in cytoplasm. The interactions of AQP4 and Kir with ${\alpha}-syntrophin$, an adaptor of dystrophin complex, were disrupted by cerebral ischemia. Conclusion : The deranged spatial buffering function of astrocytes due to mislocalized AQP4/Kir4.1 channel as well as increased assembly of $Ca^{2+}$ permeable AMPA receptors might contribute to the development of edema formation and the excitotoxic neuronal cell death during ischemia.

• Nuclear Engineering and Technology
• /
• 제55권8호
• /
• pp.2984-2996
• /
• 2023

A 100 kW thermal power pool-type light water reactor and Pu(Be) as a fast neutron source were used to determine the appropriate carrier for irradiating boron-containing samples with neutron beams. The tested materials (carriers) were subjected to neutron beams in the reactor's tangential channel. The geometrical arrangement of experimental facilities relative to the neutron beam trajectory, as well as the effect of sample thickness on the count rate, were investigated. The majority of the detectable charged particles emitted by the neutron beam's interaction with tested materials and the detector's detecting layer are protons (recoiled hydrogen) and particles generated in nuclear reactions (protons and alpha particles), respectively. Stopping and Range of Ions in Matter (SRIM) software was used to do theoretical calculations for the range of expected released particles in various materials, including human tissue. The results of measurement and calculation are in good agreement. According to experiments and theoretical calculations, the number of protons emitted by tissue-like materials may commit a dose comparable to that of boron capture reactions. Furthermore, the range of protons is significantly larger than that of alpha particles, which most probably changes dose distribution in healthy cells surrounding the tumor, which is undesirable in the BNCT approach.

• 대한토목학회논문집
• /
• 제11권1호
• /
• pp.117-124
• /
• 1991

운동량방정식을 이용한 하천만곡부 외측제방에 작용하는 단위면적당 수류력은 흐름의 특성, 토사의 특성 및 만곡부의 기하학적 인자의 함수인 곡률계수로 표현할 수 있다. 일반적으로 곡률비가 2.0~4.1인 경우에 외측제방에 작용하는 수류력이 가장크게 나타나는데 한강하류부의 경우 곡률비가 2.0~4.0에 집중된 것은 전구간에서 제방침식을 받게될 가능성이 높을 것으로 사료되어 하천개수계획수립시 필수적으로 고려되어야 하며 철저한 호안공 등의 방법으로 보완되어야 할 것이다. 한편 곡률계수가 최대인 곡률비의 범위가 1963년의 경우 2.21~4.42이고 1981년에는 1.93~3.54이며, 인위적인 하천개 보수공사를 고려한 년간 평균유로이동률이 1967년까지 4.68m/yr이고 1981년까지는 10.48m/yr이다.

• 생물정신의학
• /
• 제19권1호
• /
• pp.65-69
• /
• 2012

Objectives : Much is still unknown about the neurophysiological mechanisms or dynamics of the sleep onset process. Detrended fluctuation analysis (DFA) is a new tool for the analysis of electroencephalography (EEG) that may give us additional information about electrophysiological changes. The purpose of this study is to analyze long-range correlations of electroencephalographic signals by DFA and their changes in the sleep onset process. Methods : Thirty channel EEG was recorded in 61 healthy subjects (male:female=34:27, age=$27.2{\pm}3.0$ years). The scaling exponents, alpha, were calculated by DFA and compared between four kinds of 30s sleep-wakefulness states such as wakefulness, transition period, early sleep, and late sleep (stage 1). These four states were selected by the distribution of alpha and theta waves in O1 and O2 electrodes. Results : The scaling exponents, alpha, were significantly different in the four states during sleep onset periods, and also varied with the thirty leads. The interaction between the sleep states and the leads was significant. The means (${\pm}$ standard deviation) of alphas for the states were 0.94 (${\pm}0.12$), 0.98 (${\pm}0.12$), 1.10 (${\pm}0.10$), 1.07 (${\pm}0.07$) in the wakefulness, transitional period, early sleep and late sleep state respectively. The mean alpha of anterior fifteen leads was greater than that of posterior fifteen leads, and the two regions showed the different pattern of changes of the alpha during the sleep onset periods. Conclusions : The characteristic findings in the sleep onset period were the increasing pattern of scaling exponent of DFA, and the pattern was slightly but significantly different between fronto-temporal and parieto-occipital regions. It suggests that the long-range correlations of EEG have a tendency of increasing from wakefulness to early sleep, but anterior and posterior brain regions have different dynamical process. DFA, one of the nonlinear analytical methods for time series, may be a useful tool for the investigation of the sleep onset period.

• The Korean Journal of Physiology and Pharmacology
• /
• 제15권4호
• /
• pp.195-201
• /
• 2011

The flavonoid quercetin is a low molecular weight compound generally found in apple, gingko, tomato, onion and other red-colored fruits and vegetables. Like other flavonoids, quercetin has diverse pharmacological actions. However, relatively little is known about the influence of quercetin effects in the regulation of ligand-gated ion channels. Previously, we reported that quercetin regulates subsets of nicotinic acetylcholine receptors such as ${\alpha}3{\beta}4$, ${\alpha}7$ and ${\alpha}9{\alpha}10$. Presently, we investigated the effects of quercetin on muscle-type of nicotinic acetylcholine receptor channel activity expressed in Xenopus oocytes after injection of cRNA encoding human fetal or adult muscle-type of nicotinic acetylcholine receptor subunits. Acetylcholine treatment elicited an inward peak current ($I_{ACh}$) in oocytes expressing both muscle-type of nicotinic acetylcholine receptors and co-treatment of quercetin with acetylcholine inhibited $I_{ACh}$. Pre-treatment of quercetin further inhibited $I_{ACh}$ in oocytes expressing adult and fetal muscle-type nicotinic acetylcholine receptors. The inhibition of $I_{ACh}$ by quercetin was reversible and concentration-dependent. The $IC_{50}$ of quercetin was $18.9{\pm}1.2{\mu}M$ in oocytes expressing adult muscle-type nicotinic acetylcholine receptor. The inhibition of $I_{ACh}$ by quercetin was voltage-independent and non-competitive. These results indicate that quercetin might regulate human muscle-type nicotinic acetylcholine receptor channel activity and that quercetin-mediated regulation of muscle-type nicotinic acetylcholine receptor might be coupled to regulation of neuromuscular junction activity.

• 대한수의학회지
• /
• 제28권1호
• /
• pp.29-36
• /
• 1988

To examine the selectivity of verapamil, used in the cardiovascular diseases, on alpha-1 and alpha-2 adrenoceptor-induced pressor rsponses, effects of verapamil on alpha-adrenoceptor agonist-induced pressor responses were investigated in urethane-anesthetized rabbits, spinal rabbits, rats and pithed rats. To evaluate the effects of verapamil on each pressor response induced by norepinephrine, phenylephrine and clonidine, these agonists were previously injected into a ear vein, and then same procedures were performed 1~2 min after treatment with intravenous verapamil. The results are summarized as follows: 1. Intravenous verapamil produced dose-dependent depressor response in rabbits and rats. 2. Pressor responses to intravenous norepinephrine($10{\mu}g/kg$) and phenylphrine($30{\mu}g/kg$) were inhibited by pretreatment with intravenous verapamil in rabbits and no difference was noted between the degree of both inhibitions of the pressor response by verapamil. 3. Pressor responses to intravenous norepinephrine($3{\mu}g/kg$), phenylephrine($20{\mu}g/kg$) and clonidine ($300{\mu}g/kg$) were inhibited by pretreatment with intravenous verapamil in spinal rabbits. No difference was noted between the inhibition of norepinephrine-induced pressor response and that of phenylephrine-induced pressor response by verapamil. The inhibition of clonidine-induced pressor response by verapamil was more prominent than that of norepinephrine- or phenylephrine-induced pressor response. 4. Pressor responses to intravenous norepinephrine($3{\mu}g/kg$) and phenylephrine($10{\mu}g/kg$) were inhibited by pretreatment with intravenous verapairlil in rats and no difference was noted between the degree of both inhibitions of the pressor response by verapamil. 5. Pressor responses to intravenous norepinephrine ($3{\mu}g/kg$), phenylephrine($30{\mu}g/kg$) and clonidine($100{\mu}g/kg$) were inhibited by pretreatment with intravenous verapamil in pithed rats. No difference was noted between the inhibition of norepinephrine-induced pressor response and that of phenylephrine-induced pressor response by verapamil. The inhibition of clonidine-induced pressor response by verapamil was more prominent than that of norepinephrine- or phenylephrine-induced pressor response. These results suggest that verapamil significantly inhibits both pressor responses mediated by alpha-1 and alpha-2 adrenoceptors and the inhibition is greater in alpha-2 adrenoceptor-induced response than in alpha-1 adrenoceptor-induced one, and calcium channel takes part in the process of the pressor response mediated by alpha-1 adrenoceptors as well as alpha-2 adrenoceptors.