• Korean Journal of Cognitive Science
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• v.11 no.3_4
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• pp.83-93
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• 2000

The effect of immediate and delayed recognition memory on event-related potential (ERP) was studied using a continuous recognition memory task and event-related potential (ERP). Among 240 stimulus words 40 words were not repeated. 100 were immediately repeated and 100 were repeated after 5 intervening words. All words presented only once during the experiment were referred to as new words. Subjects responded faster and more accurately to words repeated immediately than to new words a and to those repeated after intervening words. In terms of ERP results the immediately repeated words were associated with large P300 amplitude, early P300 latency and a absence of N400. while words repeated after a delay were associated with small P300 a amplitude. late P300 latency and the presence of N400. N400 was elicited only to new w words and to those repeated after a delay. The general morphology of the waveform was s similar for three stimulus-presentation conditions until around 3l0ms after the onset of stimulus. These results indicate that immediate and delayed recognition memory could be dissociated into two distinct processes possibly being mediated by different cerebral mechanism, and the dissociation between two types of recognition memory emerges around 3l0ms poststim'ulus. The immediate and delayed recognition memory for words are considered in terms of template matching and memory searching.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.306-310
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• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.1
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• pp.9-14
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• 2000

$K^+$ currents play multiple roles in the excitability of dorsal root ganglion (DRG) neurons. Influences on these currents change the shape of the action potential, its firing threshold and the resting membrane potential. In this study, whole cell configuration of patch clamp technique had been applied to record the blocking effect of capsaicin, a lipophilic alkaloid, on the delayed rectifier $K^+$ current in cultured small diameter DRG neurons of adult rat. Capsaicin reduced the amplitude of $K^+$ current in dose dependent manner, and the concentration-dependence curve was well described by the Hill equation with $K_D$ value of $19.1{\mu}M.$ The blocking effect of capsaicin was reversible. Capsaicin $(10 {\mu}M)$ shifted the steady-state inactivation curve in the hyperpolarizing direction by about 15 mV and increased the rate of inactivation. The voltage dependence of activation was not affected by capsaicin. These multiple effects of capsaicin may suggest that capsaicin bind to the region of $K^+$ channel, participating in inactivation process.

• Annals of Clinical Neurophysiology
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• v.23 no.2
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• pp.69-81
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• 2021

Cortico-cortical evoked potential (CCEP) mapping is a rapidly developing method for visualizing the brain network and estimating cortical excitability. The CCEP comprises the early N1 component the occurs at 10-30 ms poststimulation, indicating anatomic connectivity, and the late N2 component that appears at < 200 ms poststimulation, suggesting long-lasting effective connectivity. A later component at 200-1,000 ms poststimulation can also appear as a delayed response in some studied areas. Such delayed responses occur in areas with changed excitability, such as an epileptogenic zone. CCEP mapping has been used to examine the brain connections causally in functional systems such as the language, auditory, and visual systems as well as in anatomic regions including the frontoparietal neocortices and hippocampal limbic areas. Task-based CCEPs can be used to measure behavior. In addition to evaluations of the brain connectome, single-pulse electrical stimulation (SPES) can reflect cortical excitability, and so it could be used to predict a seizure onset zone. CCEP brain mapping and SPES investigations could be applied both extraoperatively and intraoperatively. These underused electrophysiologic tools in basic and clinical neuroscience might be powerful methods for providing insight into measures of brain connectivity and dynamics. Analyses of CCEPs might enable us to identify causal relationships between brain areas during cortical processing, and to develop a new paradigm of effective therapeutic neuromodulation in the future.

• Korean Journal of Radiology
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• v.22 no.4
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• pp.604-611
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• 2021

Objective: The aim of this pilot study was to investigate the potential of early-phase single-photon emission computed tomography (SPECT)/computed tomography (CT) using technetium-99m methyl diphosphonate (^99mTc-MDP) for diagnosing osteomyelitis (OM). Materials and Methods: Twenty-one patients with suspected OM were enrolled retrospectively. Three-phase bone scan (TPBS), early-phase SPECT/CT (immediately after blood pool planar imaging), and delayed-phase SPECT/CT (immediately after delayed planar imaging) were performed. The final diagnoses were established through surgery or clinical follow-up for over 6 months. We compared three diagnostic criteria based on (I) TPBS alone, (II) combined TPBS and delayed-phase SPECT/CT, and (III) early-phase SPECT/CT alone. Results: OM was diagnosed in 11 of 21 patients (nine surgically and two clinically). Of the 11 OM patients, criterion-I, criterion-II, and criterion-III were positive in six, seven, and 10 patients, respectively. Of the 10 non-OM patients, criterion-I, criterion-II, and criterion-III were negative in five, five, and seven patients, respectively. The sensitivity/specificity/accuracy of criterion-I, criterion-II, and criterion-III for diagnosing OM were 54.5%/50.0%/55.0%, 63.6%/50.0%/57.1%, and 90.9%/70.0%/87.5%, respectively. Conclusion: This pilot study demonstrated the potential of using the early-phase SPECT/CT to diagnose OM. Based on the results, prospective studies with a larger sample size should be conducted to confirm the efficacy of early-phase SPECT/CT.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.305-310
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• 2010

The human $ether$-$a$-$go$-$go$-related gene ($hERG$) channel is important for repolarization in human myocardium and is a common target for drugs that prolong the QT interval. We studied the effects of two antipsychotics, tiapride and sulpiride, on hERG channels expressed in $Xenopus$ oocytes and also on delayed rectifier $K^+$ currents in guinea pig cardiomyocytes. Neither the amplitude of the hERG outward currents measured at the end of the voltage pulse, nor the amplitude of hERG tail currents, showed any concentration-dependent changes with either tiapride or sulpiride ($3{\sim}300{\mu}M$). However, our findings did show that tiapride increased the potential for half-maximal activation ($V_{1/2}$) of HERG at $10{\sim}300{\mu}M$, whereas sulpiride increased the maximum conductance ($G_{max}$) at 3, 10 and $100{\mu}M$. In guinea pig ventricular myocytes, bath applications of 100 and $500{\mu}M$ tiapride at $36^{\circ}C$ blocked rapidly activating delayed rectifier $K^+$ current ($I_{Kr}$) by 40.3% and 70.0%, respectively. Also, sulpiride at 100 and $500{\mu}M$ blocked $I_{Kr}$ by 38.9% and 76.5%, respectively. However, neither tiapride nor sulpiride significantly affected the slowly activating delayed rectifier $K^+$ current ($I_{Ks}$) at the same concentrations. Our findings suggest that the concentrations of the antipsychotics required to evoke a 50% inhibition of IKr are well above the reported therapeutic plasma concentrations of free and total compound.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.1
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• pp.1-7
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• 2002

Congenital Long QT syndrome (LQTs) is a relatively rare pathologic disorder but results frequently in sudden cardiac death. Of the six LQTs that have been clinically described, five have been worked out for their genetic and biophysical profile. Most are generated by mutations which cause a loss of function in two delayed $K^+$ currents, $i_{Ks}\;and\;i_{Kr}.$ One syndrome is generated by mutations in the $Na^+$ channel which causes essentially a gain of function in the channel. Clinically the syndromes are characterized by slowed repolarization of the cardiac ventricular action potential and the occurrence of typical arrhythmias with undulating peaks in the electrocardiogram, called Torsade de Pointes. Arrhythmias are initiated by early or delayed afterdepolarizations and continue as reentry. Triggers for cardiac events are exercise (swimming; LQT1), emotion (arousal; LQT2) and rest/sleep (LQT3). ${\beta}-blockers$ have a high efficacy in the treatment of LQT1 and LQT2. In LQT3 their use is questionable. The study of congenital LQTsyndromes is a remarkable example of how basic and clinical science converge and take profit of each other's contribution.

• Parasites, Hosts and Diseases
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• v.48 no.1
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• pp.1-7
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• 2010

Neutrophils play an important role in the human immune system for protection against such microorganisms as a protozoan parasite, Trichomonas vaginalis; however, the precise role of neutrophils in the pathogenesis of trichomoniasis is still unknown. Moreover, it is thought that trichomonal lysates and excretory-secretory products (ESP), as well as live T. vaginalis, could possibly interact with neutrophils in local tissues, including areas of inflammation induced by T. vaginalis in humans. The aim of this study was to investigate the influence of T. vaginalis lysate on the fate of neutrophils. We found that T. vaginalis lysate inhibits apoptosis of human neutrophils as revealed by Giemsa stain. Less altered mitochondrial membrane potential (MMP) and surface CD16 receptor expression also supported the idea that neutrophil apoptosis is delayed after T. vaginalis lysate stimulation. In contrast, ESP stimulated-neutrophils were similar in apoptotic features of untreated neutrophils. Maintained caspase-3 and myeloid cell leukemia-1 (Mcl-1) in neutrophils co-cultured with trichomonad lysate suggest that an intrinsic mitochondrial pathway of apoptosis was involved in T. vaginalis lysate-induced delayed neutrophil apoptosis; this phenomenon may contribute to local inflammation in trichomoniasis.

• The Journal of Information Systems
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• v.28 no.4
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• pp.251-270
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• 2019

Purpose Unlike advertising through the traditional media targeting unspecified number of people, the base of mobile environment using smartphone has expanded so that many companies can classify prospective customers according to their purpose, thereby enabling efficient targeted marketing with low cost. Design/methodology/approach This study has investigated how can marketing strategy be influenced by the price promotion type (immediate discount/delayed discount) and message framing (positive/negative) according to time pressure (low/high). Hypotheses are set through the consideration of prospect theory, endowment effect, framing effect, regulatory-focus theory, and time-pressure theory. Findings The results and interpretation of this study are as follows. First, it was found that the influence of the delayed discount on the purchase intention was larger than the immediate discount. Second, negative/loss frame messages have more influence on purchase intention than positive/profit frame messages. Third, when the price promotion type is delayed discount, the effect of the promotion message on the purchase intention when it presented by negative/loss frame is greater than the other cases. The implication of this study is that it can be used as a basic data for establishing a strategy to maximize the effectiveness of promotions effectively considering potential buyers of mobile commerce environment.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.406-414
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• 2014

Significant penetration of induction motor loads into residential neighborhood and commercial regions of local transmission systems at least partially determine a vulnerability to a fault induced delayed voltage recovery (FIDVR) event. Highly concentrated induction motor loads with constant torque could stall in response to low voltages associated with system faults. FIDVR is caused by wide spread stalling of small HVAC units (residential air conditioner) during transmission level faults. An under voltage load shedding scheme (UVLS) can be an effective component in a strategy to manage FIDVR risk and limit the any potential disturbance. Under Voltage Load Shedding take advantage of the plan to recovery the voltage of the system by shedding the load ways to alleviation FIDVR.