• Korean Journal of Plant Taxonomy
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• v.50 no.3
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• pp.253-261
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• 2020

Carex splendentissima U. Kang & J. M. Chung, endemic to the Korean peninsula, is characterized by staminate terminal spikes and glabrous elliptic perigynia. Based on its broad leaves, androgynous spikes, and tri-stigmatic features, the species has been placed in Carex sect. Siderostictae Franch. ex Ohwi, an East Asian section and a basal group in the genus. To clarify the monophyly and phylogenetic position of the species, a molecular study using the internal transcribed spacer region of nuclear ribosomal DNA and chloroplast DNA (trnL-F) data was conducted. The DNA sequence data of ten taxa in sect. Siderostictae and closely related taxa (two taxa in sect. Surculosae) with outgroups were analyzed based on maximum parsimony and maximum likelihood (ML) criteria. In the analyses, C. splendentissima was monophyletic and placed within the Siderostictae clade (sect. Siderostictae + two species of sect. Surculosae), forming a clade with C. ciliatomarginata and C. pachygyna (endemic to Japan). The clade (C. splendentissima + C. ciliatomarginata + C. pachygyna) shows evidence of diploidy. Furthermore, C. splendentissima is a sister to C. ciliatomarginata in the ML tree, and the two taxa have staminate terminal spikes. This study also updates the distribution of C. splendentissima and provides keys to the four Korean taxa in sect. Siderostictae. To conserve the endemic species C. splendentissima, further research on its genetic and ecological features should be conducted at the population level.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.6
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• pp.28-32
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• 1980

A digital system has been designed for the detection of abnormal spikes appearing in the epileptic patient's electroencephalogram(EEG). The detection is based on the waveform characteristics of spikes, such as the large slope, the sharpness of the apex, and the time duration of the spike. After the patient's data are collected and processed suing a minicomputer and A/D converter, the computer algorithms recognize the spikes based on the parameters representing the above waveform characteristics.

• Journal of Life Science
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• v.7 no.1
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• pp.59-65
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• 1997

In this experiment, gene actions were analysized for seven barley parents in order to obtain basic information on their genetic improvement by diallel crosses. The results obtained were summarized as follows. In analysis of variance, additive, dominant, maternal and reciprocal effects were observed significantly for culm length, tiller number, number of spiked per plant, culm diameter, awn length, leaf width, number of grains per spike, and 1000 grain weight. Over-dominance was shown by Vr-Wr graphic analysis in five characters such as tiller number, number of spikes per plant, length of flag leaf, number of grains per spike, and 1000 grain weight, and partial dominance in four characters such as culm length, culm diameter, awn length, and leaf width. Component of genetic varience analyzed for four characters such as culm diameter, awn length, length of flag leaf, and leaf width showed that additive effects were higher than dominant effects. Culm length, tiller number, number of spikes per plant, number of grains per spike, and 1000 grain weight showed dominant effects higher than additive effects. The narrow-sense heritability for awn length, leaf width, and number of grains per spike showed high values as more than 0.62, while broad-sense heritability for culm length, number of spikes per plant, culm diameter, awn length, leaf width, number of grains per spike, and 1000 grain weight showed high values as more than 0.65.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.6
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• pp.303-307
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• 2006

The effects of ethanol on corticostriatal synaptic transmission were examined, using extracellular recording and analysis of population spike amplitudes in rat brain slices, to study how acute ethanol intoxication impairs striatal function. Ethanol caused a decrease in population spike amplitudes in a dose dependent manner ($50{\sim}200mM$). Pretreatment with picrotoxin, a ${\gamma}-amino$ butyric acid $(GABA)_{A}$ receptor antagonist, increased the population spikes but ethanol (100 mM) was still effective in decreasing the population spikes under this condition. In the presence of $_{(DL)}-2-amino-5-phosphonovaleric$ acid (APV), N-methyl-D-aspartate (NMDA) receptor antagonist, the inhibitory action of ethanol on population spikes was not shown. These results suggest that ethanol inhibits the glutamatergic corticostriatal synaptic transmission through blockade of NMDA receptors.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1683-1693
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• 2017

This paper analyses the harmonic pollution to power grids caused by thyristor-controlled devices. It also formulates a mathematic derivation for the voltage spikes in thyristor-controlled branches to explain the harmonic and EMI derived from the reverse-recovery characteristics of the thyristor. With an equivalent nonlinear time-varying voltage source, a detailed simulation model is established, and the periodic dynamic switching characteristic of the thyristor can be explicitly implied. The simulation results are consistent with the probed results from on-site measurements. An improved trigger system with gate-shorted circuit structure is proposed to reduce the voltage spikes that cause EMI. The experimental results indicate that a prototype with the improved trigger system can effectively suppress the voltage spikes.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.7-14
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• 2000

Inhibitory cells are critically involved in shaping normal hippocampal function and are thought to be important elements in the development of hippocampal pathologies. The present study was carried out in hippocampal CA1 area in vivo to compare with hippocampal slice studies. Intracellular and extracellular recordings with or without bicuculline electrodes were obtained in the intact brain of anesthetized rats, and cells were intracellularty labelled with neurobiotin. Electrical stimulation of fimbria-fornix resulted in an initial short-latency population spike. In the presence of $10{\mu}M$ bicuculline, orthodromic stimulation resulted in bursts of population spikes. The amplitude of population spikes in the CA1 region increased with stimulus intensity, as did the number of population spikes when the field recording electrode contained $10{\mu}M$ bicuculline. We measured the level of excitability in the CA1 area, using a paired-pulse stimulus paradigm to evoke population spikes. Population spikes showed strong paired-pulse inhibition at short interstimulus intervals. Burst afterdischarges up to 400 ms were observed after paired-pulse stimulus. These result suggest that hippocampal CA1 inhibitory interneurons can affect the excitability of pyramidal neurons that can not be appreciated in conventional in vitro preparation.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.266-275
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• 1997

Anemarrhena asphodeloides BUNGE is one of important medicinal crops, which has been collected or/and cultivated for its rhizomes. The main medicinal ingredient of the A. asphodeloides Bunge rhizomes is a saponin, which is known to have medical values for diaphoresis, sedatives and biuresis. However, studies on cultural methods and breeding works on this plant have not been made in detail. To increase productivity and to improve quality of crops, it is important to collect cultivated and wild lines, to classify them based on morphological and genetic characteristics, and to select superior pure lines at first. Therefore, total 20 A. asphodeloides lines collected were cultivated at the fieldof Chungnam Provincial Administration of Rural Development in 1995 to study the agronomic characteristics and to classify them based on morphological characteristics. Characteristics related with reproductive organ such as the number of spikes per plant and peduncle length showed greater variations than vegetative organrelated characteristics such as leaf length and rhizome length based on the coefficient of variation. Vigorous shoot growth resulted in better development of reproductive organs such as peduncle length and number of spikes per plant. However, the development of spikes was negatively correlated with chlorophyll content. Characteristics of underground parts were more significantly correlated with spike characteristics than aerial part characteristics. A. asphodeloides tested in this study were classified into 2 groups (group A and group B) based on centroid linkage cluster analysis. Group A showed more vigorous shoot growth with more leaves and spikes per plant, longer peduncle length, thicker peduncle diameter and higher shoot dry weight than group B. Group A could be further classified into 2 sub-groups based on leaf size, spike length and peduncle diameter, while group B also could be classified based on number of leaves, number of spikes and shoot dry weight.

• International Journal of Oral Biology
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• v.31 no.4
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• pp.113-118
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• 2006

In the primary sensory neuron of the mesencephalic trigeminal nucleus (MTN), the peripheral axon supplies a large number of annulospiral endings surrounding intrafusal fibers encapsulated in single muscle spindles while the central axon sends only a few number of synapses onto single ${\alpha}-motoneurons({\alpha}-MNs)$. Therefore, the ${\alpha}-{\gamma}$ linkage is thought to be very crucial in the jaw-closing movement. Spike activity in a ${\gamma}-motoneuron\;({\gamma}-MN)$ would induce a large number of impulses in single peripheral axons by activating many intrafusal fibers simultaneously, subsequently causing an activation of ${\alpha}-MNs$ in spite of the small number of synapses. Thus, the activity of ${\gamma}-MNs$ may be vital for modulation of jaw-closing movements. Independently of such a spindle activity modulated by ${\gamma}-MNs$, somatic depolarization in MTN neurons is known to trigger the oscillatory spike activity. Nevertheless, the trafficking of these spikes arising from the two distinct sources of MTN neurons is not well understood. In this short review, switching among multiple functional modes of MTN neurons is discussed. Subsequently, it will be discussed which mode can support the ${\alpha}-{\gamma}$ linkage. In our most recent study, simultaneous patch-clamp recordings from the soma and axon hillock revealed a spike-back-propagation from the spike-initiation site in the stem axon to the soma in response to a somatic current pulse. The persistent $Na^+$ current was found to be responsible for the spike-initiation in the stem axon, the activation threshold of which was lower than those of soma spikes. Somatic inputs or impulses arising from the sensory ending, whichever trigger spikes in the stem axon first, would be forwarded through the central axon to the target synapse. We also demonstrated that at hyperpolarized membrane potentials, 4-AP-sensitive $K^+$ current ($IK_{4-AP}$) exerts two opposing effects on spikes depending on their origins; the suppression of spike initiation by increasing the apparent electrotonic distance between the soma and the spike-initiation site, and the facilitation of axonal spike invasion at higher frequencies by decreasing the spike duration and the refractory period. Through this mechanism, the spindle activity caused by ${\gamma}-MNs$ would be safely forwarded to ${\alpha}-MNs$. Thus, soma spikes shaped differentially by this $IK_{4-AP}$ depending on their origins would reflect which one of the two inputs was forwarded to the target synapses.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.155-164
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• 2007

A new species, Arca koumaci Lutaenko et Maestrati n. sp. (Bivalvia: Arcidae), is described from New Caledonia. The species is characterized by the small size, the convex shell with a strong posterior umbonal ridge covered by spikes, the widely curved ventral margin, and presence of cancellate sculpture and convergent marginal teeth. Presence of spikes on the posterior ridge is a unique morphological feature recorded for the first time in the genus. It is proposed that the only subgenus, namely Pliocene A. (Arcoptera) Heilprin, 1887, apart from nominative, can be recognized in the genus. Three morphological types are distinguished within the genus based on shell shape and sculpture. Bathymetric analysis shows that representatives of Arca inhabit water depths down to 175 m, and more than half of Recent species were found below 50 m. Types of A. bouvieri P. Fischer, 1874, Arca boucardi Jousseaume, 1894, Arca avellana Lamarck, 1819, and Arca retusa Lamarck, 1819 are illustrated.

• Journal of Sensor Science and Technology
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• v.27 no.3
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• pp.143-149
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• 2018

In this paper, we introduce an edge-spike modulation method for visible light communication (VLC). This method is effective in preventing LED flicker and 120 Hz noise interference in base-band VLC. In the VLC transmitter, edge-spikes are generated by passing the digital data through a simple RC-high pass filter (HPF). The LED modulation of the edge-spikes does not change the average power of the LED light; thus it prevents LED flicker. In the VLC receiver, the 120 Hz noise from other lighting lamps is easily eliminated by RC-HPF, while the edge-spike signal is detected normally. In our experiment, the message of an air-quality sensor was successfully transmitted using edge-spike modulation. This structure is useful in constructing, e.g., wireless gas monitoring sensor systems to warn and prevent harmful gas leakage accidents in buildings using LED light.