• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.7
• /
• pp.740-749
• /
• 2023

The ocean plays a vital role in the international carbon cycle, absorbing human-induced atmospheric carbon and preventing further atmospheric carbon accumulation. However, while the ocean had been considered a victim of climate change, it did not receive much attention as a solution for climate change in the major agenda of UNFCCC. Recently, a growing awareness that the ocean can provide numerous potentials to handle untapped issues to address the climate crisis has arisen, which has prompted discussions to strengthen ocean-based climate action. Since 2020, UNFCCC "Ocean and climate change dialogue" has been a forum to integrate and strengthen the ocean-climate nexus. This calls for integrating ocean action into climate action and the relevant sectors. In this regard, this study examined the background and international trends of ocean-based climate action and presented the author's perspective on the scope of content that such action should pursue and the direction to achieve it. In addition, this study identified tasks of the integrated approach and advancement of co-benefit as ways to strengthen ocean-based climate action, and it suggested domestic countermeasures for the Korean marine policy on climate change based on this.

• The Journal of Korean Academy of Sensory Integration
• /
• v.8 no.1
• /
• pp.41-49
• /
• 2010

Objective : Multisensory integration (MSI) is the essential process to use diverse sensory information for cognitive task or execution of motor action. Especially, visual and somatosensory integration is critical for motor behavior and coordination. This study was designed to explain spatial and temporal characteristics of visual and somatosensory integration by neurophysiological research method that identifies the time course and brain location of the SI process. Methods : Electroencephalography (EEG) and event-related potential (ERP) is used in this study in order to observe neural activities when integrating visual and tactile input. We calculate the linear summation (SUM) of visual-related potentials (VEPs) and somatosensory-related potentials (SEPs), and compared the SUM with simultaneously presented visual-tactile ERPs(SIM) Results : There were significant differences between the SIM and SUM in later time epochs (about 200-300ms) at contralateral somatosensory areas (C4) and occipital cortices (O1&O2). The amplitude of the SIM was mathematically larger than the summed signals, implying that the integration made some extra neural activities. Conclusion : This study provides some empirical neural evidence of that multisensory integration is more powerful than just combing two unisensory inputs in the brain and ERP data reveals neural signature relating to multisensory integrative process. Since this study is preliminary pilot study, larger population and criteria are needed for level of the significance. Further study is recommended to consider issues including effect of internally-driven attention and laterality of interaction to make the evidence by this study solid.

• The Journal of Korean Physical Therapy
• /
• v.20 no.3
• /
• pp.9-18
• /
• 2008

Purpose: We determined the effect of global synkinesis(GS) on gait ability, muscle contraction, and central neuron action potentials in post-stroke hemiplegic subjects. Methods: Thirty hemiplegia patients were evaluated for walking ability, muscle contraction, central neuron action potential, and comparing differences between the H-GS(high-global synkinesis) group and L-GS(low-global synkinesis) group. To obtain the GS level, surface electromyography(EMG) data were digitized and processed to root mean square(RMS). Walking ability was tested with a modified motor assessment scale(MMAS), a 10 m walking test, timed up and go(TUG) test, and a Fugl-Meyer assessment(FMA). Muscle contraction ability was measured as maximal isometric contraction(MIC) peak, MIC slope, and MIC ramp up using mechanomyography(MMG). Central neuron action potential was measured as the H/Mmax ratio or V/Mmax ratio using EMG. The data were analyzed with t-tests to determine the statistical significance. Results: MMAS(p<0.01), 10 m walking velocity(p<0.01), TUG(p<0.01), FMA-HKA(Hip, Knee, Ankle)(p<0.05), FMA-coordination(p<0.05), MIC peak (p<0.05), MIC slope(p<0.01), and MIC ramp up(p<0.05) were significantly different between H-GS and L-GS, as was the V/Mmax ratio(p<0.05), but H/Mmax was not. Conclusion: Lower GS levels indicated better walking ability and motor function. Therefore, intervention programs should consider GS levels in gait training of chronic hemiplegia.

• The Korean Journal of Physiology and Pharmacology
• /
• v.10 no.3
• /
• pp.131-135
• /
• 2006

Coeruleo-vestibular pathway which connects locus coeruleus and vestibular nuclei is noradrenergic. This study was designed to elucidate the effects of phenylephrine on the spontaneous activity of acutely isolated medial vestibular nuclear neurons of rat by whole-cell patch-clamp technique. Sprague-Dawley rats, aged 14 to 16 days, were used. After enzymatic digestion, dissociated medial vestibular neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. In current-clamp mode, the frequency of spontaneous action potential of medial vestibular nuclear neurons was decreased by phenylephrine (n=15). Phenylephrine increased the amplitude of afterhyperpolarization without changes in the resting membrane potential and spike width. In voltage-clamp mode, the whole potassium currents of the medial vestibular nuclear neurons were increased by phenylephrine (n=12). These experimental results suggest that ${\alpha}-receptor$ mediates the inhibitory effects on the neuronal activity of the medial vestibular nuclear neuron.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.3
• /
• pp.169-175
• /
• 2000

To learn the developmental changes in intrinsic electrophysiological properties of the second order taste neurons, whole cell recordings from the developing nucleus of the solitary tract neurons were done in brainstem slices of postnatal rats. Rats aged from postnatal 0 to 21 days (P0-P21) were used, being divided into 3 age groups: postnatal first week (P0-P7 days), second week (P8-P14 days), and third week (P15-P21 days). Slices containing gustatory NTS were cut horizontally in the thickness of $300\;{\mu}m.$ Whole cell recordings were obtained from neurons in response to a series of hyperpolarizing and depolarizing current pulses. The intrinsic electrophysiological properties of the rostral NTS (rNTS) neurons were compared among the age groups. Depolarizing current pulses evoked a train of action potentials in all neurons of all age groups. The resting membrane potential and input resistance of the neurons did not show any significant differences during the postnatal 3 weeks. The time constant, however, decreased during the development. Duration of action potential measured at half maximum amplitude was longer in younger age groups. Both the maximum rate of rise and the maximum rate of fall in the action potential increased during the first 3 weeks postnatal. Electrophysiologically more than half neurons were type III. In summary, it is suggested that developmental changes in electrophysiological properties in rNTS occur during the first three weeks in rats.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.4
• /
• pp.681-688
• /
• 2009

To better delineate the changes in corticospinal excitability when older adults are asked to observe and/or imagine actions, 22 right-handed older adults without neurological abnormalities were included in this study. The amplitude and latency of motor evoked potentials (MEPs) by transcranial magnetic stimulation were recorded in the abductor pollicis brevis of the dominant hand during passive observation/imagery/active observation of slow/fast action of abduction of right thumb and also at resting state. Thus, active observation showed better changes than passive, but slow and fast action revealed no difference at all.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.46-46
• /
• 2003

Salviae Miltiorrhizae Radix has been used for treatment of cardiovascular diseases in oriental medicine. To investigate the possible involvement of cardiac ion channel in this effect, we examined electrophysiological effects of the extract of Salviae Miltiorrhizae Radix on action potentials and ionic currents in rat ventricular myocytes. The extracts of Salviae Miltiorrhizae Radix were fractionated into nine fractions, and the effect of each fraction on action potential was tested. The fraction containing monomethyl lithospermic acid-A (LSA-A) induced a significant prolongation of action potential duration (APD). LSA-B which is a major component of Salviae Miltiorrhizae Radix, however, did not cause a significant effect. In voltage clamp experiments, the effects of LSA-A on K currents, Ca currents and Na currents were tested. Neither K currents nor L-type Ca currents were affected by LSA-A. On the contrary, LSA-A significantly slowed down the inactivation kinetics of the Na current with no effect on the fast component of the inactivation process. The amplitude of the peak current and the voltage-dependence of activation were not changed by LSA-A. The effect of LSA-A on Na current was abolished when high concentration of $Ca^{2+}$ buffer (10 mM BAPTA) was included in the pipette solution or when Ca2+ current was blocked by nicardipine (1 $\mu$M) in the bath solution.n.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.30 no.1
• /
• pp.28-33
• /
• 2019

Background and Objectives : Laryngeal electromyography (LEMG) is valuable to evaluate the innervation status of the laryngeal muscles and the prognosis of vocal fold paralysis (VFP). However, there is a lack of agreement on quantitative interpretation of LEMG. The aim of this study is to measure the motor unit action potentials (MUAP) quantitatively in order to find cut-off values of amplitude, duration, phase for unilateral vocal fold paralysis patients. Materials and Method : Retrospective chart review was performed for the unilateral VFP patients who underwent LEMG from March 2016 to May 2018. Patient's demography, cause of VFP, vocal cord mobility, and LEMG finding were analyzed. The difference between normal and paralyzed vocal folds and cut-off values of duration, amplitude, and phase in MUAP were evaluated. Results : Thirty-six patients were enrolled in this study. Paralyzed vocal fold had significantly longer duration (p=0.021), lower amplitude (p=0.000), and smaller phase (p=0.012) than the normal. The cut-off values of duration, amplitude, and phase in MUAP for unilateral VFP were 5.15 ms, $68.35{\mu}V$, and 1.85 respectively. Conclusion : An analysis of MUAP successfully provided quantitative differences between normal and paralyzed vocal folds. But, additional research is needed to get more available cut-off value which is helpful to evaluate the status of laryngeal innervations.

• Restorative Dentistry and Endodontics
• /
• v.17 no.1
• /
• pp.10-21
• /
• 1992

The purpose of this study was to investigate the analgesic effect of eugenol, capsaicin and demethoxy-NE. Young adult cats, weighing 2.0 to 3.0kg, were used. Each animal was anesthetized (${\alpha}$-chloralose 60mg per kg body weight) and divided into four groups; control, eugenol, capsaicin and demethoxy-NE group. The anterior digastric muscles were exposed and a pair of electrodes was inserted to record the electromyograms. To expose the pulp, each canine teeth was prepared with a low speed bur under cooling and used for recording anterior digastric muscular EMGs evoked by noxious stimulation of dental pulp. To observe effects on jaw opening reflex, inferior alveolar nerve of both sides were exposed for drug application and wire electrodes were inserted in anterior digstric muscle for recording the EMGs. To observe effects on action potential, saphenous nerves of both sides were exposed and three tissue pools were made from surrounding tissue. The most distal pool was used for applying stimulation, the most proximal one for recording of action potential, and the other one for drug application. One side of inferior alveolar nerve and saphenous nerve were used for eugenol, capsaicin, or demethoxy-NE application, the other side of nerve for control experiments(only vehicle application). Anterior digastric muscular EMGs evoked by noxious stimulation of dental pulp were recorded before drug application, immediate after drug application, at 60 and 120 minutes, and 5 days after drug application. Action potentials were recorded before drug application, immediate after 30 minutes drug application, at 30, 60 and 120 minutes after drug had been washed out. The results were as follows; 1. Eugenol had a continuous blocking effect on the anterior digastric muscular EMGs evoked by noxious pulp stimulation and after 5 days, showed completely blocking effect. 2. After 5 days, demethoxy-NE applied to dental pulp had a considerable blocking effect on the jaw opening retlex evoked by noxious stimulation but capsaicin had no significant effect. 3. After 5 days, eugenol group showed the strongest blocking effect among the all experimental groups on the jaw opening reflex evoked by noxious stimulation of dental pulp and capsaicin group showed the weakest blocking effect. 4. Eugenol had a completely blocking effect on the action potential conductivity of peripheral nerve. Capsaicin and demethoxy-NE had the blocking effect on the action potential conductivity of ${\alpha}$-and C-nerve fibers. 5. Capsaicin, demethoxy-NE and eugenol applied to inferior alveolar nerve surppressed the jaw opening reflex evoked by noxious stimulation of dental pulp.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1635-1638
• /
• 1997

A measurement of conduction veloctiy of the action potentials along the muscle fibres has been applied to various diagnosis. When we measure muscle fiber conduction velocity, it occurs that not only change of conduction velocity but alos inclusion of mipulse component by physiological and experimental reason. So, robuster time delay estimation algorithm than general methods[1] is needed to find correct time delay form these signals. In this paper we, propose new time delay estimation algorithms, robust in impulsive noise, by using characteristic of .alpha.-stable distribution whcih defines impulsive noise well. Then we apply proposed algorthms to measure muscle fiber conduction velocity and compare them with other studies.