• Toxicological Research
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• v.11 no.1
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• pp.63-68
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• 1995

N-methyl-D-aspartate(NMDA) receptor has been well known as an important mediator of several forms of neural and behavioral plasticity. But different results were reported about the effect of MK-801 or dextromethorphan on opioid dependence. The present studies examined whether NMDA receptor antagonists can alter the opioid dependence and tolerance in rodents. Naloxone precipitated withdrawal symptoms and changes of locomotor activities were observed in MK-801 or dextromethorphan pretreated morphine-dependent rats. Tail-flick assay was used for morphine analgesia and tolerance was found after 4 day's consecutive injections (10 mg/kg, s.c., twice/day) of morphine in mice. Locomotor activity was increased and the withdrawal symptoms were decreased by the pretreatment of MK-801 in morphine-dependent rats. But 0.3 mg/kg i.p. of MK-801 intensified the body weight loss and produced severe ataxia and rotation although some withdrawal signs were attenuated. Morphine induced analgesic tolerance was inhibited by the pretreatment of MK-801 and dextromethorphan. Dextromethorphan was more potent than MK-801 in inhibiting the development of the analgesic tolerance in mice. These results suggest that NMDA system may be involved in opioid withdrawal and analgesic tolerance but appropriate caution should be requested when MK-801 is used in combination with opioid because of untoward neurologic signs.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1081-1090
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• 2019

Detailed pulse shape analysis of a Geiger-$M{\ddot{u}}ller$ counter is performed to understand the pulse shape dependence on operating voltage. New data is presented to demonstrate that not all pulses generated in a GM counter are identical. In fact, there is a strong correlation between the operating voltage and the pulse shape. Similar to detector deadtime, pulse shapes fall in three distinct regions. For low voltage region, where deadtime was reported to reduce with increasing voltage, pulse generated in this region was observed to have a fixed pulse width with a variable tail. The pulse width and fall time of the tail was observed to be a function of applied voltage; exponentially reducing with increasing voltage with an exponent of negative 6E-04 and 2E-03 respectively. The second region showed a pulse without any significant tail. During this time the detector deadtime was earlier reported to be at its minimum. The highest voltage region demonstrated a different deadtime mechanism where the second pulse was reduced in width. During this time the deadtime seemed to be increasing with increasing voltage. This data allows us to gain some unique insight into the phenomenon of GM detector deadtime not reported thus far.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.93-96
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• 1990

The characteristics of an inverted staggered-type hydrogenated amorphous silicon thin film transistor has been analyzed by employing numerical simulation. The field effect mobility and threshold voltage are characterized as a function of density of deep and tail states and lattice temperature. It has been found that the density of deep states plays an important role of determining the threshold voltage, while the field effect mobility are very sensitive to the slope of band tail states. Also, the numerically temperature dependence of field effect mobility and threshold voltage has been in good agreements with the experimental results.

• Fisheries and Aquatic Sciences
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• v.3 no.3_4
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• pp.188-194
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• 2000

A protease purified from hepatopancreas of shrimp, Penaeus japonicus, had maximum activity at $70^{\circ}C$ and in neutral and alkaline pH ranges. Specific activity at optimum reaction condition of the protease was estimated to be approximately 12 U/mg/min. The protease was stable in neutral and alkaline pH ranges and activity was retained after heat treatment at $50^{\circ}C$ for 30 min. Apparent $K_m$ and $V_{max}$ value against casein substrate were estimated to be $0.29\%$ and $7.8see^{-1}$, respectively, and those against N-CBZ-L-tyrosine p-nitropheny1 ester (CBZ­Tyr-NE) were 0.38 mM and $2,400 see^{-1}$, respectively. The N-termina1 sequence of the protease showed high homology to the trypsin from same species and the proteases from shrimp. Myosin heavy chain (MHC) from shrimp tail meat was the most susceptible to the protease and actin/tropomyosin were degraded progressively during 4 hr incubation, but to a lesser degree than MHC.

• Communications for Statistical Applications and Methods
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• v.9 no.3
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• pp.649-663
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• 2002

We consider an unlimited fluid queueing model which has Fractional Brownian motion(FBM) as an input and a single server of constant service rate. By using the result of Duffield and O'Connell(6), we investigate the asymptotic tail-distribution of the stationary work-load. When there are multiple homogeneous FBM inputs, the workload distribution is similar to that of the queue with one FBM input; whereas for the heterogeneous sources the asymptotic work-load distributions is dominated by the source with the largest Hurst parameter.

• Journal of the Korean Mathematical Society
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• v.56 no.2
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• pp.457-473
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• 2019

In this paper, we investigate weak laws of large numbers for weighted coordinatewise pairwise negative quadrant dependence random vectors in Hilbert spaces in the case that the decay order of tail probability is r for some 0 < r < 2. Moreover, we extend results concerning Pareto-Zipf distributions and St. Petersburg game.

• Korean Journal of Veterinary Research
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• v.34 no.1
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• pp.25-36
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• 1994

The inward tail current after a short depolarizing pulse has been known as Na-Ca exchange current activated by intracellular calcium which forms late plateau of the action potential in rabbit atrial myocytes. Chloride conductance which is also dependent upon calcium concentration has been reported as a possible tail current in many other excitable tissues. Thus, in order to investigate the exsitance of the calcium activated chloride current and its contribution to tail current, whole cell voltage clamp measurement has been made in single atrial cells of the rabbit. The current was recorded during repolarization following a brief 2 ms depolarizing pulse to +40mV from a holding potential of -70mV. When voltage-sensitive transient outward current was blocked by 2 mM 4-aminopyridine or replacement potassium with cesium, the tail current were abolished by ryanodine$(1{\mu}M)$ or diltiazem$(10{\mu}M)$ and turned out to be calcium dependent. The magnitudes of the tail currents were increased when intracellular chloride concentration was increased to 131 mM from 21 mM. The current was decreased by extracellular sodium reduction when intracellular chloride concentration was low(21 mM), but it was little affected by extracellular sodium reduction when intracellual chloride concentration was high(131 mM). The current-voltage relationship of the difference current before and after extracellular sodium reduction, shows an exponential voltage dependence with the largest magnitude of the current occurring at negative potentials, with is similar to current-voltage relationship at negative potentials, which is similar to current-voltage relationship of Na-Ca exchange current. The current was also decreased by $10{\mu}M$ niflumic acid and 1 mM bumetanide, which is well known anion channel blockers. The reversal potentials shifted according to changes in chloride concentration. The current-voltage relationships of the niflumic acid-sensitive currents in high and low concentration of chloride were well fitted to those predicted as chloride current. From the above results, it is concluded that calcium activated chloride component exists in the tail current with Na-Ca exchange current and it shows the reversal of tail current. Therefore it is thought that in the physiologic condition it leads to rapid end of action potential which inhibits calcium influx and it contributes to maintain the low intracellular calcium concentration with Na-Ca exchange mechanism.

• Electrical & Electronic Materials
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• v.10 no.5
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• pp.467-472
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• 1997

In this study, we investigated the thickness dependence of thermal bleaching(TB) effect as well as photo-induced scalar phenomena, such as photodrakening(PD) effect and photorefraction(PR) change, in chalcogenide A $s_{40}$ G $e_{10}$S $e_{15}$ $S_{35}$ thin films. We found that when these films were exposed for 15 minutes using blue-pass filtered Hg lamp(~4300$\AA$) after annealing for 30 minutes around the glass transition temperature Tg(20$0^{\circ}C$), the refractive index change ($\Delta$n) was varied up to 0.02~0.46 according to each thickness condition and the optical energy gap ($\Delta$ $E_{op}$ ) was shifted to a longer wavelength of approximately 0.67eV, especially for 1000$\AA$-thickness. Also, the TB PD effects have been understood by the results related to optical absorption characteristics. The TB effect could be estimated as increasing the stabilization of amorphous chalcogenide films since absorption slope of extended regions(U) was not changed by annealing. On the other hand, the PD effect could be understood as due to the enhancement of disorder since U and the slope of Urbachs tail(1/F) around an absorption edge were decreased by exposing.ing.n edge were decreased by exposing.

• Journal of Korea Port Economic Association
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• v.36 no.4
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• pp.93-106
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• 2020

Trade is an important economic activity. In particular, since the establishment of the World Trade Organization (WTO), the scope of trade has been expanding due to events such as the entry of China into the WTO in 2001, the establishment of a multilateral trading system, mitigation and integration of trade barriers, and the establishment of the free trade agreement (FTA). Despite the expansion of the trade market, however, extreme events such as the 2008 global financial crisis, the 2016 Brexit, and the 2018 US-China trade war have had a direct negative impact on the trade market. Therefore, the present this study analyzed the dependence structure between the international shipping freight rate index, a variable representing trade activities, and the trade uncertainty between the US and China. The following is a summary of the analysis results. First, the US-Chinese trade policy uncertainty and international shipping freight rate index presented a Frank copula and rotated Clayton copula 270° distribution, respectively, showing the same distribution structure for each country. Second, the Kendall's tau correlation revealed a negative dependence between the international shipping freight rate index and US-Chinese trade policy uncertainty. The degree of dependence was greater in the combination of uncertainty in China's trade policy and international shipping freight rates. In other words, the dependence of global demand and trade policy uncertainty confirmed that China was stronger than the US. Finally, the tail dependence results revealed that the US-Chinese trade policy uncertainty and international shipping freight rates were independent of each other. This means that extreme events related to the trade policy uncertainty or international shipping rate index were not affected by each other.

• Journal of the Korean Magnetic Resonance Society
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• v.9 no.1
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• pp.21-28
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• 2005

$^{11}B$ nuclear magnetic resonance (NMR) measurements have been performed to investigate electronic structures and vortex states of $M_gB_2$ superconductor. The central transition shows a narrow peak down to 25 K at 3.15 T. Below 25 K, an extra line starts to show up and dominates. The extra line is broad and asymmetric with a long tail in the high frequency side, which confirms that this originates from vortex pinning below the irreversibility temperature. From temperature evolution of the fraction and linewidth of the broad portion, temperature dependence of coherence length and penetration depth are extracted.