• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.123-133
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• 1992

This study was conducted to clarify progressed changes of plant types and the effects of the physiological and ecological components on improving ideotype of winter wheat. 12 wheat varieties were planted at the experimental farm of Wheat and Barley Research Institute in Suwon in 1990. As results of intensive wheat breeding for early maturity since 1959, heading, flowering and maturing dates have been shortened by 17, 15 and 14 dagys, respectively. The shortened days from sowing to heading and from heading to flowering contributed to the early maturity to improved. Physiological factors associated with heading time of wheat could be reprsented by growth habit, photoperiod responses, earliness in narrow sense and winter hardiness. For improving an early maturity of winter wheat, it would desired to maintain some degree of winter habit(III-IV), and recombination of more insensitivity to short day length and more shortened earliness in narrow sense than that of Saemil and Chugoku 81, and higher degree of winter hardiness. For improving the early maturity the more effective way must be of shortened days from sowing to heading, and days from flowering to maturity than days from heading to flowering. Ideotype of wheat will be desired to recombine two semi-dwarf genes with erect plant type being about 70-80cm, less stem elongation by late spring, long spike and many grains per spikelet. Average spike weight ratio was about 45-49% in high-yielding varieties, stem fresh weight was lighter, but spike fresh weight was heavier in new one while leaf fresh weight was similar to each other during the maturing periods. Average spike dry weight ratio was higher about 40～48%, and stem and leaf blade dry weights were lower in the newly bred varieties. Stem dry weight was heavier than spike or leaf dry weight in the old varieties of Yungkwang, Jangwang and Jinkwang. Leaf area index for the varieties showed normal distribution curve as the maximum point in booting stage. The maximum point of this curve come in early maturing wheat, and late in old one. The maximum points of LAI were 6.4～6.8 in the high-yielding varieties. Totals of LAI in each period investigated of old one were higher than those of newly bred being 24.6～28.8. Chlorophyll content of the high-yielding varieties of Chokwang, Geurumil and Saemil as higher than that of the old varieties Jangkwang, Jinkwang, Wonkwang and Sinkwang from regrowing period to April 21. after then slightly and even after heading. Net assimilation rate (NAR) was higher in high-yielding varieties with good plant type, and lower in old ones. Grain yield of the newly released varieties increased rapidly but slowly in the old ones. Change in water content of grain at the growing stage in newly bred was lower than that of the old bred. Diminishing rate of water content of grain in establishment per day was 1.2% average that of the old varieties including Yungkwang was 1.5%, and those of the newly bred including Chokwang were 0.9～1.1%. Chokwang, Naemil, and Saemil were the highest-yielding varieties of the Korean cultivars. Yields were increased by spikes per m$^2$, grain weight for the varieties bred in Suwon, and by spikes per m$^2$ for the varieties bred in Milyang.

• Journal of Life Science
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• v.25 no.8
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• pp.953-959
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• 2015

Optogenetics is the combination of optical and molecular strategies to control designated molecular and cellular activities in living tissues and cells using genetically encoded light-sensitive proteins. It involves the use of light to rapidly gate the membrane channels that allows for ion movement. Optogenetics began with the placing of light-sensitive proteins from green algae inside specific types of brain cells. The cells can then be turned on or off with pulses of blue and yellow light. Using the naturally occurring algal protein Channelrhodopsin-2 (ChR2), a rapidly gated light-sensitive cation channel, the number and frequency of action potentials can be controlled. The ChR2 provides a way to manipulate a single type of neuron while affecting no others, an unprecedented specificity. This technology allows the use of light to alter neural processing at the level of single spikes and synaptic events, yielding a widely applicable tool for neuroscientists and biomedical engineers. An improbable combination of green algae, lasers, gene therapy and fiber optics made it possible to map neural circuits deep inside the brain with a precision that has never been possible before. This will help identify the causes of disorders like depression, anxiety, schizophrenia, addiction, sleep disorder, and autism. Optogenetics could improve upon existing implanted devices that are used to treat Parkinson’s disease, obsessive-compulsive disorder and other ailments with pulses of electricity. An optogenetics device could hit more specific subsets of brain cells than those devices can. Applications of optogenetic tools in nonneuronal cells are on the rise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.24-33
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• 2017

Multitemporal MODIS vegetation index (VI) data are widely used in vegetation monitoring research into environmental and climate change, since they provide a profile of vegetation activity. However, MODIS data inevitably contain disturbances caused by the presence of clouds, atmospheric variability, and instrument problems, which impede the analysis of the NDVI time series data and limit its application utility. For this reason, preprocessing to reduce the noise and reconstruct high-quality temporal data streams is required for VI analysis. In this study, a data reconstruction method for MODIS NDVI is proposed to restore bad or missing data based on the statistical properties of the oscillations in the NDVI temporal dynamics. The first derivatives enable us to examine the monotonic properties of a function in the data stream and to detect anomalous changes, such as sudden spikes and drops. In this approach, only noisy data are corrected, while the other data are left intact to preserve the detailed temporal dynamics for further VI analysis. The proposed method was successfully tested and evaluated with simulated data and NDVI time series data covering Baekdu Mountain, located in the northern part of North Korea, over the period of interest from 2006 to 2012. The results show that it can be effectively employed as a preprocessing method for data reconstruction in MODIS NDVI analysis.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.2
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• pp.167-175
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• 2015

A retinal prosthesis is being developed for the restoration of vision in patients with retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Determining optimal electrical stimulation parameters for the prosthesis is one of the most important elements for the development of a viable retinal prosthesis. Here, we investigated the effects of different charge-balanced biphasic pulses with regard to their effectiveness in evoking retinal ganglion cell (RGC) responses. Retinal degeneration (rd1) mice were used (n=17). From the ex-vivo retinal preparation, retinal patches were placed ganglion cell layer down onto an $8{\times}8$ multielectrode array (MEA) and RGC responses were recorded while applying electrical stimuli. For asymmetric pulses, 1st phase of the pulse is the same with symmetric pulse but the amplitude of 2nd phase of the pulse is less than $10{\mu}A$ and charge balanced condition is satisfied by lengthening the duration of the pulse. For intensities (or duration) modulation, duration (or amplitude) of the pulse was fixed to $500{\mu}s$($30{\mu}A$), changing the intensities (or duration) from 2 to $60{\mu}A$(60 to $1000{\mu}s$). RGCs were classified as response-positive when PSTH showed multiple (3~4) peaks within 400 ms post stimulus and the number of spikes was at least 30% more than that for the immediate pre-stimulus 400 ms period. RGC responses were well modulated both with anodic and cathodic phase-1st biphasic pulses. Cathodic phase-1st pulses produced significantly better modulation of RGC activity than anodic phase-1st pulses regardless of symmetry of the pulse.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.89-94
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• 2004

The arterial pressure is regulated by the nervous and humoral mechanisms. The neuronal regulation is mostly carried out by the autonomic nervous system through the rostral ventrolateral medulla (RVLM), a key area for the cardiovascular regulation, and the humoral regulation is mediated by a number of substances, including the angiotensin (Ang) II and vasopressin. Recent studies suggest that central interleukin-1 (IL-1) activates the sympathetic nervous system and produces hypertension. The present study was undertaken to elucidate whether IL-1 and Ang II interact in the regulation of cardiovascular responses to the stress of hemorrhage. Thus, Sprague-Dawley rats were anesthetized and both femoral arteries were cannulated for direct measurement of arterial pressure and heart rate (HR) and for inducing hemorrhage. A guide cannula was placed into the lateral ventricle for injection of IL-1 $(0.1,\;1,\;10,\;20\;ng/2\;{\mu}l)$ or Ang II $(600\;ng/10\;{\mu}l)$. A glass microelectrode was inserted into the RVLM to record the single unit spike potential. Barosensitive neurons were identified by an increased number of single unit spikes in RVLM following intravenous injection of nitroprusside. I.c.v. $IL-1\;{\beta}$ increased mean arterial pressure (MAP) in a dose-dependent fashion, but HR in a dose-independent pattern. The baroreceptor reflex sensitivity was not affected by i.c.v. $IL-1\;{\beta}$. Both i.c.v. $IL-1\;{\alpha}\;and\;{\beta}$ produced similar increase in MAP and HR. When hemorrhage was induced after i.c.v. injection of $IL-1\;{\beta}$, the magnitude of MAP fall was not different from the control. The $IL-1\;{\beta}$ group showed a smaller decrease in HR and a lower spike potential count in RVLM than the control. MAP fall in response to hemorrhage after i.c.v. injection of Ang II was not different from the control. When both IL-1 and Ang II were simultaneously injected i.c.v., however, MAP fall was significantly smaller than the control, and HR was increased rather than decreased. These data suggest that IL-1, a defense immune mediator, manifests a hypertensive action in the central nervous system and attenuates the hypotensive response to hemorrhage by interaction with Ang II.

• Korean Journal of Optics and Photonics
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• v.7 no.3
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• pp.251-259
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• 1996

Two-Photon Fluorescence (TPF) experiment measures temporal width of an amplified short laser pulse which has passed through a four-pass Nd: glass amplifier, after selecting a single pulse from pulse train Q-switched and mode-locked(QSML) in Nd:YLF master oscillator. Determination of pulsewidth and pulseshape was also made with detection of autocorrelation trace of CW mode-locked pulse train by using noncollinear type I Second Harmonic Generation (SHG) method. The observed TPF track showed various patterns, depending on pulse-selecting position in QSML pulse train. That is, autocorrelation of a pulse extracted at front of the train displayed smooth pulse shape, while one from the trailing part of the train created many sharp spikes and substructure in the pulse. By TPF method, pulsewidth was measured to be 44.4 ps with contrast ratio of 2.86 which enabled us to find out energy fraction of a pulse to total energy, (sum of pulse and background); we obtain the value of 0.62. Pulsewidth of 46.6ps was also acquired in another SHG experiment with the help of only mode-locked pulse train. On the other hand, we confirmed that shape of the pulse is close to $sech^2$ one as a result of fitting the SHG autocorrelation signal with various functions. With simulation using this $sech^2$ type of pulse, pulsewidth reduction of the beam, having passed through four-pass amplifier, was also verified.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.1
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• pp.79-83
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• 1985

This experiment was carried out in order to determine the optimum harvesting time of tetraploid Italian ryegrass. Moisture content, 1000-seed weight, germination and seed shattering were investigated at six harvesting times after anthesis in 1984 at Suweon. The results are summarized as follows; 1. Seed moisture content was slowly decreased until 24 days and fastly decreased from 24 days after anthesis. The daily mean moisture loss during the ripening period was about 1.5 percentage. 2. The maximum 1000-seed weight was reached at 24 days after anthesis and 1000-seed weight of Waseking was heavier than that of Giant. 3. Shattering began at 17-20 days after anthesis and thereafter rapidly increased. 4. Germination was 50% at 10 days after anthesis and maximum germination was reached at 24 days. 5. Considering germination, 1000-seed weight and shattering, the optimum harvest time was 24 to 27 days after anthesis. At this time, moisture content was 55.0 to 43.5 percent and two to five seeds per ten spikes were shed by shaking at the vertical point.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.36-44
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• 2007

In order to evaluate the utilization of immature green barley kernels as food processing material, these experiments were carried out to analyze free sugars, free amino acids, mineral contents and color of two naked barley varieties according to their heading dates. Contents such as moisture, protein, fat, ash, and free sugars were gradually decreased according to the days after heading of the nonwaxy naked barley 'Saessalbori' and waxy naked barley 'Hinchalssalbori', while crude fiber and starch were gradually increased. Contents like maltose and maltotriose in immature green kernels were high, but free amino acids showed a tendency to decrease, among which the alanine content was the highest. As barley matured, beta-glucan content, redness and yellowness increased, while lightness decreased. Considering chemical composition and color, the immature green cereals were produced through blanching the spikes harvested before the yellow ripe stage around $26{\sim}27$ days after heading. The optimum duration of harvest was very limited to produce green whole grains. The harvested green barley cereals is able to eat raw barley or cook it as food processing material.

• Toxicological Research
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• v.17
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• pp.47-57
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• 2001

Alzheimer's disease (AD) is the most common cause of dementia in the elderly, and its pathology is characterized by the presence of numerous numbers of senile plaques and neurofibrillary tangles. Several genetic and transgenic studies have indicated that excess amount of $\beta$-amyloid protein (A$\beta$) is produced by mutations of $\beta$TEX>$\beta$-amyloid precursor protein and causes learning impairment. Moreover, $A\beta$ has a toxic effect on cultured nerve cells. To prepare AD model animals, we have examined continuous (2 weeks) infusion of $A\beta$ into the cerebral ventricle of rats. Continuous infusion of $A\beta$ induces learning impairment in water maze and passive avoidance tasks, and decreases choline acetyltransferase activity in the frontal cortex and hippocampus. Immunohistochemical analysis revealed diffuse depositions of $A\beta$ in the cerebral cortex and hippocampus around the ventricle. Furthermore, the nicotine-evoked release of acetylcholine and dopamine in the frontal cortex/hippocampus and striatum, respectively, is decreased in the $A\beta$-infused group. Perfusion of nicotine (50 $\mu\textrm{M}$) reduced the amplitude of electrically evoked population spikes in the CA1 pyramidal cells of the control group, but not in those of the $A\beta$-infused group, suggesting the impairment of nicotinic signaling in the $A\beta$-infused group. In fact, Kd, but not Bmax, values for ［$^3H$］ cytisine binding in the hippocampus significantly increased in the $A\beta$-infused rats. suggesting the decrease in affinity of nicotinic acetylcholine receptors. Long-term potentiation (LTP) induced by tetanic stimulations in CA1 pyramidal cells, which is thought to be an essential mechanism underlying learning and memory, was readily observed in the control group, whereas it was impaired in the $A\beta$-infused group. Taken together, these results suggest that $A\beta$ infusion impairs the signal transduction mechanisms via nicotinic acetylcholine receptors. This dysfunction may be responsible, at least in part, for the impairment of LTP induction and may lead to learning and memory impairment. We also found the reduction of glutathione- and Mn-superoxide dismutase-like immunoreactivity in the brains of $A\beta$-infused rats. Administration of antioxidants or nootropics alleviated learning and memory impairment induced by $A\beta$ infusion. We believe that investigation of currently available transgenic and non-transgenic animal models for AD will help to clarify the pathogenic mechanisms and allow assessment of new therapeutic strategies.

• Journal of Science Education
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• v.38 no.1
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• pp.41-56
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• 2014

This study has developed STEAM educational program designed to cultivate topophilia using Jeonbuk educational resources and applied the program to a science camp. Topophilia is a sense of attachment and nostalgia towards one's birth place and specific objects, which can create positive affection and act as motivations for learning to the students. We developed a 32-hour STEAM program which consisted of 8 experiential activities and 2 travel programs including Gochujang, Hanok Village, a reverse ice spikes in Mai Mountain, and art works by Choi Book. In particular, we emphasized the fun of class, voluntary learning, and process of attaching significance by providing aesthetic and emotional experience of synesthesia. As a result of application, the students' level of confidence(Likert scale level 4, 2.5 points) in science and the level of interests(3.3 points) have improved. The pleasant experience of voluntary learning and active participation in class provided meaningful memories through value recognition and significance ascription. 93.3% of the students participated said they would recommend the Topophilia science camp to their peers. The level of satisfaction overall was 3.8 points(Likert scale level 5) and the program received positive evaluations that the class was fun and interesting(4.1 points).