• Korean Journal of Microbiology
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• v.45 no.3
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• pp.251-256
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• 2009

Leaf samples and bulbs showing characteristic symptoms of virus infection were collected from Gang-won, Chung-nam, and Jeju Province of Korea in 2008-2009. Three viruses, Lily symptomless virus (LSV), Lily mottle virus (LMoV), and Cucumber mosaic virus (CMV) were detected by RT-PCR. Virus-infected plant samples were identified; 12 plants with LSV, 20 plants with LMoV, and 1 plant with CMV. Of the twelve LSV infected samples, seven samples were found to be mix-infected with LMoV and LSV. Symptoms of LMoV and LSV mixed infection were fairly severe, like as vein clearing, leaf curling, leaf mottling, leaf mosaic, and yellow streaking. Mixed infection with LMoV and LSV was also found in lily bulbs which have been stored under unfavorable environmental conditions. LMoV predominated in our tests, whereas spread of Lilyvirus X (LVX) was not found. The nucleotide sequences of coat protein (CP) region of seven isolates (4 LMoV, 2 LSV, and 1 CMV) were compared with the corresponding regions of LMoV (AJ564636), LSV (AJ516059) and CMV(AJ296154). The nucleotide sequence homologies between reference viruses and seven isolates were 95-99%. Complete sequencing of seven isolates is necessary to obtain more information on the molecular characteristics of these viruses as well as to increase sensitivity and rapidity of viral detection.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.50-56
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• 2016

Direct seeding of sorghum (Sorghum bicolor L. Moench) has a problem of low yield including poor establishment. This poor establishment results from poor quality seed, poor seedbed preparation, seedling pests, poor sowing technique and high soil temperature. This study sought to establish the age at which sorghum seedlings can be transplanted with minimal effects on grain yield. Transplants were raised in 128 nursery tray pot. Five seedling ages were established by transplanting at 10 (T10), 15 (T15), 20 (T20), 25 (T25) and 30 (T30) days after planting (DAP). The treatment combinations were arranged in a randomized complete block design and replicated three times with an individual plot size of $6{\times}5m^2$. Each plot had five ridges with a planting space of $0.60{\times}0.20m^2$ at one plants per stand. Results showed that seedling age on transplanting significantly affected growths and yields to sorghum after transplanting. Plant heights and diameters of transplants at T15 were longer than the other transplants. Conclusively, The advantages of this practice were better control of crop density and greater yields; either to fill gaps after emerging and thinning of crops or to compensate for a growth period that was too short for a complete crop cycle.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.251-255
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• 2008

This study was carried out in 2002 to determine the usefulness of Jeju scoria for a component of a growth medium and optimum planting density of 'Dejima' seed potatoes (Solanum tuberosum L.) grown in a wick hydroponic system. The minitubers ($7.0{\pm}0.2\;g$) produced in an aeroponics system were planted at five planting densities (3 to 15 tubers/box; 19 to $95\;tubers/m^2$) in polystyrene boxes (51 cm long $\times$ 31 cm wide $\times$ 20 cm high) containing two media (perlite + peatmoss and Jeju scoria + peatmoss 1:2, v/v mixtures). There were no significant interactions between medium and planting density for the growth and tuber yield traits. Shoot growth and the number of tubers per plant were not significantly affected by the media. However, tuber yield was higher in the perlite + peatmoss mixture than in the Jeju scoria + peatmoss mixture. The percentage of underdeveloped plants ranged from 8.3 to 14.7% at four lower planting densities (3 to 12 tubers/ box), and was 25.8% at the highest planting density (15 tubers/box). As planting density was increased from 3 to 15 tubers per box, seed potato (${\geq}5\;g$ tuber) number increased from 101 to 269 and yield from 6.3 to $11.6\;kg/m^2$. These results indicate that the perlite + peatmoss mixture might be more suitable for seed potato production in the wick hydroponic system, and considering the percentage of underdeveloped plants and tuber yield, optimum planting density would be 56 to $76\;tubers/m^2$ in the system depending on availability of seed potatoes.

• Development and Reproduction
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• v.10 no.3
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• pp.203-209
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• 2006

Ethane 1,2-Dimethane sulfonate(EDS), a toxin which specifically kills Leydig cells(LC), has been widely used to prepare the reversible testosterone(T) depletion rat model. Previous studies including our own clearly demonstrated that the dramatic weight loss of the T-dependent accessory sex organs such as epididymis and seminal vesicle in this 'LC knock-out' rats. These weight loss could be derived from massive and abrupt death of the cells via apoptotic process. The present study was performed to test the effect of EDS administration on the expression of some apoptotic genes in the rat epididymis. Adult male Sprague-Dawley rats($300{\sim}350$ g B.W.) were injected with single dose of EDS(75 mg/kg, i.p.) and sacrificed on Weeks 0, 1, 2, 3, 4, 5, 6 and 7. Tissue weights and the numbers of the epididymal sperm were measured. The transcriptional activities of the bcl-2, bax, Fas and Fas ligand(Fas-L) were evaluated by semi-quantitative RT-PCR. As expected, the weights and the sperm counts of epididymis declined progressively after the EDS treatment during Week 1 and 2. These decrements were discontinued with a gradual return towards normal during Weeks $5{\sim}7$, although the maximal recoveries of the epididymal weights(71%) and sperm count(38%) were subnormal on Week 7. The initial level of bcl-2 transcripts persisted to Week 6 then elevated significantly on Week 7. The level of bax transcripts significantly decreased on Week 6, and no remarkable change was found in the rest of the experimental period. The transcripts for the Fas in epididymis elevated during Weeks $1{\sim}2$, returned to normal on Week 3, and the level persisted to the Week 7. Similarly, the level of Fas-L transcripts elevated during Weeks $1{\sim}3$ and returned to normal after Week 4. Our results demonstrated the transient T depletion by EDS administration could induce the changes in expression of the apoptotic genes in rat epididymis. The activation of Fas and Fas-L in the epididymis of EDS-treated rats might be responsible for the initial apototic process and consequently the tissue damage and the sperm loss. Future studies will attempt to determine the precise molecular mechanism(s) of apoptosis in the rat epididymis.

• The Journal of Korean Philosophical History
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• no.54
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• pp.153-184
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• 2017

During the Pre-Qin(秦) Dynasty era, there were the records that there had been many calendar systems, such as $g{\check{u}}-li{\grave{u}}-l{\grave{i}}$(古六曆 : six ancient calendar systems). Then, the fact that particularly $zh{\bar{o}}u-l{\grave{i}}$(周曆) and $xi{\grave{a}}-l{\grave{i}}$(夏曆) were mainly discussed among them resulted from a lot of discussions from the differences in the calendar system in "$Ch{\bar{u}}n-qi{\bar{u}}$(春秋)" known to have been written by Confucius from the calendar system in "$X{\acute{i}}ng-xi{\grave{a}}-zh{\bar{i}}-sh{\acute{i}}$(行夏之時 : implement the calendar of Ha dynasty.)" that Confucius mentioned himself to his disciple. $zh{\bar{o}}u-l{\grave{i}}$(周曆) with $d{\bar{o}}ngzh{\grave{i}}-yu{\grave{e}}$(冬至月 : the 11th month of the lunar calendar) as the first month of a year had the system of the lunar calendar, and $xi{\grave{a}}-l{\grave{i}}$(夏曆) called as the calendar of Ha(夏) dynasty had the system of $ji{\acute{e}}-q{\grave{i}}-l{\grave{i}}$(節氣曆 : a kind of the solar calendar that divides one year of 365 days into 24 solar terms) with $y{\acute{i}}n-yu{\grave{e}}$(寅月 :one month from the present Feb 5) as the first month of a year. These two calendars had definite differences in the first months of a year, names of seasons, and the lunar calendar and the solar calendar. The fundamental reason why Confucius recommended the performance of $xi{\grave{a}}-l{\grave{i}}$(夏曆) as a way to run the nation was not that it started from the philosophical view of the universe that among the 'three $zh{\bar{e}}ng$'(三正)' of $ti{\bar{a}}n-zh{\bar{e}}ng$(天正 : the first month of a year with the heaven as the standard), $d{\grave{i}}-zh{\bar{e}}ng$(地正 : the first month of a year with the earth as the standard) and $r{\acute{e}}n-zh{\bar{e}}ng$(人正 : the first month of a year with humans as the standard), but that he wanted to emphasize the importance of practical national economic policies to enhance agricultural productivity. It becomes the criterion that even though Confucius emphasized that politicians should not have moral flaws ideally, with regard to public policies, he wanted to stress politicians' duties based on the reality a lot.