• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.232-247
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• 1987

Three rice varietis, Dongjinbyeo, Daecheongbyeo and Chucheongbyeo, which are leading cultivars in the Chungnam area, were planted to determine their effects of mixture on the plant characteristics and the blast occurrence. The summary obtained is as follows; 1. The heading dates of each cultivars were not affected by the mixing culture. Only a day was delayed in heading date of Chucheongbyeo under commonly standard fertilizer level. 2. The effects of cultivar mixture on the plant height was high when low level of fertilizer were applied. Of the cultivar mixture, the mixing of Dongjinbyeo and Daecheongbyeo shoed 5.1% of plant height increase. The effects of mixture on the tillering number were apparent only under the standard fertilizer level. The mixture of Dongjinbyeo and Chucheongbyeo was effective in increasing the tillering number up to 5.7% over mean tillering number of each cultivars. 3. The stem height tended to increase as the fertilizer level increased and the effects of cultivar mixture on the stem height was high. The stem height of mixture of Dongjinbyeo and Daecheongbyeo was highest compared with other mixture cropping. On the contrary, the panicle length was shortened as the fertilizer level decreased and cultivars were mixed. Among the cultivar mixtures, the mixture of Dongjinbyeo and Daecheongbyeo showed the most effectives of increasing the panicle length. 4. The total dry weight of mixed and pure cultivars were compared. The mixture of two cultivars was effective in increasing the dry weight of rice upto 3.5% over the average of dry weight of each cultivars. When three cultivars were mixed, there were 8.5% of dry weight increase over not mixed cultivars. The effects of mixture on the dry weight were more apparent under standard fertilizer level. 5. The rates of Neck and Node and Branch Blast occurrence were reduced when cultivars were mixed, and their reduction rates were 11.7% and 14.0%, respectively. The occurrence of Blasts was also decreased under the lowest fertilizer level than the standard fertilizer level. The least Blast occurrence was obtained when Dongjinbyeo and Daecheongbyeo were mixed cropped. 6. Significantly high number of spikelets of per square meter was observed when Chucheongbyeo and Dongjinbyeo were mixed. However, the spikelets of panicle were the lowest when Chucheongbyeo and Dongjinbyeo were mixed. The number of panicles per square meter was increased as the fertilizer levels increased, while the number of spikelets per panicle increased as the fertilizer level decreased. 7. The effects of mixture on the maturing were apparent regardless of the fertilizer level. The 1000 grain weight was higher when lower level of fertilizer was applied. The effects of cultivar mixture on the 1000 grain weight were more apparent in the plots of Chucheongbyeo and Dongjinbyeo mixture and three cultivar mixture. 8. The grain yield increased when cultivars mixed. The increment under mixing cropping was 4.6% over mono cropping. The effects of cultivar mixture on the yield increase were more apparent under lower levels of fertilizer application. The highest yield increase was obtained when Chucheongbyeo and Daecheongbyeo were mixed, and the rate of yield increase was 6.8% over mono-cropping. 9. The grain yield was highly correlated with number of panicles per square meter and dry weight. There was not any significant relationships found among grain yield, spikelets of panicle and ripening percentage.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.254-261
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• 1995

The nationwide weed survey was conducted in lowland rice fields over whole country of Korea in 1992 in order to determine a change of weed community and to identify a major dominant weed species and/or problem weed. Based on morphological characteristics of weeds, population ratio of broad leaf weed was 42.6%, grasses weed-9.0%, sedges-33.4% and others were 15.0%. Annual weed was 33.4% while perennial weed was 66.6% in terms of life cycle of weeds. Meanwhile, there was different weed occurrence as affected by planting method of the rice plant. In hand transplanted paddy fields predominant weed species was Sagittaria trifolia L., Monochoria vaginalis Presl., and Aneilema japonica Kunth. In machine transplanted rice fields of infant and young rice seedling Eleocharis kuroguwai Ohwi. and S. trifolia L. were more predominant. There was high occurrence of M. vaginalis, Echinochloa crus-galli L., and Leesia japonica Makino in water seeding while E. crus-galli and Cyperus serotinus Rottb. were predominant weed species in dry seeded rice. Monoculture of the rice plant would cause to high occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and Sagittaria pygmaea Miq and there was higher population of S. trifolia, S. pygmaea, M. vaginalis, E crus-galli, and E. kuroguwai in double cropping system based on rice culture. In particular, there was high different weed occurrence under different transplanting times. E. kuroguwai, S. trifolia, S. pygmaea, M. vaginalis, and C. serotinus were higher population at the transplanting of 25 May and S. trifolia, E crus-galli, C. serotinus, and M. vaginalis at 10 June and S. pygmaea, E. kuroguwai, M. vaginalis, S. trifolia, and E. crusgalli at 25 June in Korea, respectively. Autumn tillage in terms of tillage time would cause more predominant weed species such as S. trifolia, E. kuroguwai, M. vaginalis, and S. pygmaea while spring tillage was higher population of E. kuroguwai, S. trifolia, E. crusgalli, M. vaginalis, and S. pygmaea. In plain area of paddy field there was higher occurrence of E. kuroguwai, S. trifolia, M. vaginalis, E. crus-galli, and S. pygmaea and in mid-mountainous area S. trifolia, E. kuroguwai, M. vaginalis, E. crus-galli, and Ludwigia prostrate Roxb. while in mountainous area S. trifolia, M. vaginalis, Potamogeton distinctus Ben., E. kuroguwai, and E. crus-galli were. In 1992 the most ten predominant weed species at the rice field of Korea based on summed dominant ratio(SDR) were E. kuroguwai > S. trifolia > E. crus-galli > M. vaginalis > S. pygmaea > C. serotinus > L. prostrate > P. distinctus > A. japonica > Scirpus juncoides Roxb.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.455-462
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• 2000

The objective of this study was to examine the physicochemical characteristics of coagulation reaction between loess and red tide organisms (RTO) and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea. The physicochemical characteristics of loess were examined for a particle size distribution, surface characteristics by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrothen closterium and Skeietonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various concentrations of loess, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number. A negative zeta potential of loess increased with increasing pH at $10^(-3)M$ NaCl solution and had -71.3 mV at pH 9.36. Loess had a positive zeta potential of +1,8 mV at pH 1.98, which resulted in a characteristic of material having an amphoteric surface charge. In NaCl and $CaCl_2$, solutions, loess had a decreasing negative zeta potential with increasing $Na^+\;and\;Ca^(+2)$ ion concentration and then didn't result in a charge reversal due to not occurring specific adsorption for $Na^+$ ion while resulted in a charge reversal due to occurring specific adsorption for $Ca^(+2)$ ion. In sea water, loess and RTO showed the similar zeta potential values of -112,1 and -9.2 mV, respectively and sea sand powder showed the highest zeta potential value of -25.7 mV in the clays. EDLs (electrical double-layers) of loess and RTO were extremely compressed due to high concentration of salts included in sea water, As a result, there didn't almost exist EDL repulsive force between loess and RTO approaching each other and then LVDW (London-yan der Waals) attractive force was always larger than EDL repulsive force to easily form a floe. Removal rates of RTO exponentially increased with increasing a loess concentration. The removal rates steeply increased until $800 mg/l$ of loess, and reached $100{\%}$ at 6,400 mg/l of loess. Removal rates of RTO exponentially increased with increasing a G-value. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction. Loess showed the highest RTO removal rates in the clays.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1998.05a
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• pp.37-54
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• 1998

This study was conducted to investigate the effects of mugwort extracts on the blood ethanol concentration, liver function and low level of cadmuim(Cd) in rats. The effects of mugwort extracts on the blood ethanol concentration was studied in Sprague-Dawley rats (10 weeks old) administered p.o. with 25% ethanol (5g/1kg body weight) and then injected with mugwort extracts (at the 2% levels of daily feed consumption compared with the concentration of catechins level in mugwort extracts) in caudal vein. SD rats were divided into five groups : control group (CON-E, only ethanol and 0.85% saline sol'n treated instead of each extracts), water extracts of mugwort treated to the control (MDW-E), ethanol extracts of mugwort treated to the control (POH-E). And then rat plasma of each time (0hr, 1hr, 2hr, 3hr) was investigated ethanol concentration by gas chromatography. Another rats were measured at the time of 0 and 5hr for the test of GOD(Glutamic Oxaloacetic Transaminase) and GPT(Glutamic Pyruvic Transaminase). Components of each extracts were analyzed by using high performance liquid chromatography. The effects of mugwort extracts on the liver function were studied in culture of rat hepatocyte composed of three groups : Control group and two groups treated with each extracts (1% & 2% MDW, 1% & 2% MOH). Condition of rat hepatocytes cultured for 36hr at $37^{\circ}C$(5% $CO_2$ incubator), number of cells, GOT and GPT activity were investigated. The results obtained were summarized as follows ; 1. Catechins level of mugwort extracts was $8{\sim}10mg/100g(MDW)$, $3{\sim}4mg/100g(MOH)$ 2. The contents of (-)-Epigallocatechin was high in MDW 3. The effects of mugwort extracts on the blood ethanol concentration were as follows; 1) The order in ethanol degradation efficiency was MDW-E > MOH-E > CON-E. 2) Ethanol concentration significantly decreased (p<0.05) in MDW-E and MOH-E. 4. The effects of mugwort extracts on the liver function were as follows; (rat hepatocytes cultured for 36hr at $37^{\circ}C$) 1) Cells condition of MDW-L was better than other groups. 2) The order in number of cells (rat hepatocytes) was 2% MDW-L >1% MDW-L >1% MOH-L > Con-L > 2% MOH-L 5. Cd treatment increased concentrations of hepatic GSH level, and decreased GOT activity in plasma. Therefore, this results suggest that the effects of mugwort extracts may an important rols in degradation ethanol and recovery liver function in body. Also, Mugwort extracts may modify the toxicities of Cd in Cd-treated rats and play an important roles in preventing the liver from various toxicants including Cd in Cd treated rats.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1998.10a
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• pp.83-106
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• 1998

This study was conducted to investigate the probiotics(acid and bile resistance, fermentation properties, viability, cholesterol assimilation, antimicrobial activity, antimutagenicity, and immunoactivation) of the strains of bifidobacteria isolated from healthy Koreans and to investigate the effects of oral administration of Bifidobacterium longum A-2 on the fecal microflora, ${\beta}-glucuronidase$ activity, pH values, Ammonia concentration. The experimental results are summarized as follows: The probiotics were tested for 23 strains including three commer챠al strains as controls. Compared to other strains, strains of A-2 and A-9 showed more acid resistance whereas A-2, A-5, A-13, A-14, A-18 and A-22 showed excellent bile resistances. The properties of bifidobacteria during fermentation were tested. Strains of A-1, A-2, A-3, A-4, A-6, and A-23 resulted in less than pH 4.5 and titratable acidity over 0.90 after 24 hr of fermentation. When the strains of A-2 was grown with glucose, maltose, and fructooligosaccharide, the acetic acid production were higher than with sorbitol and mannitol. The storage stability of the strains of A-2 and A-22 were tesed, indicating the strain A-2 was more stable over 10 days of storage at both $4^{\circ}C$ and $20^{\circ}C$ than A-22. The strains of A-8, A-10, A-11, A-12 and A-20 assimilated more than 30% of cholesterol included in the media. The strains of A-1 and A-2 showed antimicrobial activity against Sta. aureus. The antimutagenicity of the strains were also tested, showing that the mutation was suppressed more by three strains(A-2, A-12, and A-23). In addition, strain A-5 improved immunological activity(phagocytosis, $TNF-{\alpha}$, IL-6) more than other strains. In the effects of oral administration of Bif. longum A-2, the number of fecal bifidobacteria was siginificantly increased(p<0.01) and the level of fecal ${\beta}-glucuronidase$ also was siginificantly reduced(p<0.05). However there were no siginificant differences in the level of Lαctobacilli, Enterobacteriaceae, Clostridium perfringens, pH and ammonia by the administration. The results suggested that Bif. longum A-2 may be met the criteria for probiotics culture.

• Korean Journal of Agricultural Science
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• v.19 no.1
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• pp.40-50
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• 1992

This experiment was carried out to stimulate lactic starter culture for yoghurt manufacturing. A each of 1.5% of Bios 2000, CR starter medium, and Yeast extract were added to bulk medium, acidity, pH and changes in the number of lactic acid bacteria were investigated at, intervals of two hours for Lactobacillus bulgaricus and four hours for Streptococus thermophilus and Lactobacillus casei. The results obtained were summarized as follows. 1. The acidity of control arrived at 0.99% after 16 hours of incubation during the incubation of Lactobacillus bulgaricus. Whereas that of CR starter medium reached 1.00% at 12 hours of incubation. Yeast extract, 1.12% at 12 hours, and Bios 2000 reached 0.97% at 10 hours respectively, Thus, Bios 2000 showed the fastest rate of acid production. 2. When the acidity of experiment medium peaked on optimum levels. pH of control was 4.03 in 16 hours of incubation during the incubation of Lactobacillus bulgaricus. Whereas that of Bios 2000 reached 4.10 of Yeast extract reached 3.97 at 12 hours, and of CR starter medium reached 4.05 at 12 hours. 3. Lactic acid bacterial counts were $3.1{\times}10^{10}/ml$ after 16 hours of incubation during the incubation of lactobacillus bulgaricus, Whereas those of Bios 2000 reached $2.1{\times}10^{10}/ml$ at 10 hours, with the fastest stimulation of growth, The counts in CR starter medium were at $2.9{\times}10^{10}/ml$ at 12 hours, and Yeast extract were $3.8{\times}10^{10}/ml$ at 12 hours. 4. The acidity of control, CR starter medium, and Yeast extract reached 0.92% at 44 hours, and 0.96% at 32 hours, and 0.90% at 32 hours respectively, Also, that of Bios 2,000 reached 0.97% at 32 hours, which exhibited the highest, among the treatments. 5. The pH of control was 4.27 at 44 hours. that of CR starter medium was 4.33 at 40 hours and that of Yeast extract was 4.25 at 32 hours during the incubation in Streptococcus thermophilus. Besides, pH of Bios 2000 is lowest as 4.18 at 32 hours. 6. Lactic acid bacterial counts in control, CR starter medium, and Yeast extract during the incubation of Streptococcus thermophilus were $9.8{\times}10^{9}/ml$ at 44 hours,$9.5{\times}10^{8}/ml$ at 40 hours, and $9.6{\times}10^{8}/ml$ at 32 hours. And, the highest number was $2.0{\times}10^{9}/ml$ for Bios 2000 at 32 hours. 7. The acidity of control during the incubation of Lactobacillus casei reached 0.92% at 40 hours, and those of CR starter medium and Yeast extract were 0.95% at 40 hours, and 1.01% at 36 hours respectively. Also, Bios 2000 had the highest acidity as 0.94% at 32 hours. 8. The pH of control, CR starter medium and Yeast extract during the incubation Lactobacillus casei was 4.27 at 40 hours. 4.21 at 40 hours, and 4.15 at 36 hours respectively. Also, Bios 2000 showed the lowest pH, as 4.23, at 32 hours. 9. Lactic acid bacterial counts in control, CR starter medium and Yeast extract during the incubation of Lactobacillus casei were $9.4{\times}10^{7}/ml$ at 40 hours, $1.1{\times}10^{8}/ml$ at 40 hours, and $5.0{\times}10^{8}/ml$ at 36 hours respectively. And, the progress of 32 hours showed the highest number of lactic acid bacteria as$6.4{\times}10^{8}/ml$ in Bios 2000.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.75-113
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• 1982

Studies were carried out 1) to define the shape and size of sampling quadrat and its number of observations for weed experiments, 2) to characterize the growth and community of major summer weeds under upland condition and 3) to investigate the factors influencing competition between weeds and soybeans under weed-free and weedy conditions in early and late season cultures. No significant difference was noted among different shapes of quadrat (regular, rectangular, band, and circular) in the sampling efficiency of weeds. The results also suggested that the minimum size of quadrat was 0.25$m^2$ and the minimum number of replication was 2 times per plot. The major dominant weeds were about 10 species in the experimental field and the total number of weeds was in the range of 70 - 1,600 plants per $m^2$. Among the weeds Digitaria sanguinalis and Portulaca oleracea were the most dominant species. Growth amount and reproduction capability were also measured by weed species. Five different weed communities were identified in the field. The degree of dispersion by weed species and association among weeds were investigated. Intra-(within soybeans) and inter-specific (between soybeans and weeds) competition were studied in early and late season cultures of soybeans. The average yield of soybeans per plant was significantly decreased in both season cultures due to intra-specific competition as the planting density of soybeans increased, On the other hand, the average yield of soybeans per l0a was proportionally increased to the increase of planting density and the rate of its increase was more significant under weedy than weed-free condition. Most of the agronomic characteristics of soybeans were affected by weeds and its degree was greater in sparse planting than in dense planting and in early season than in late-season culture. Digitaria sanguinalis was the most competitive to soybeans in early season and both of Digitaria sanguinalis and Portulaca oleracea affected primarily the growth of soybeans in late season with about the same competitiveness. The occurrence of weeds was significantly decreased in early season and slightly decreased in late-season by dense planting of soybeans. The total growth amount of weeds was also considerably decreased by increase of soybean planting density both in early- and late-season cultures. The occurrence of Digitaria sanguinalis which was the most dominant in both seasons, and its growth amount was significantly decreased as the planting density of soybean was increased. On the other hand, the occurrence of Portulaca oleracea which was only dominant in late-season culture did not show significant response to the planting density of soybeans.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.1-40
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• 1973

There is a general tendency to increase nitrogen level in rice production to insure an increased yield. On the other hand, percentage of ripened grains is getting decreased with such an increased fertilizer level. Decreasing of the percentage is one of the important yield limiting factors. Especially the newly developed rice variety, 'Tongil' is characterized by a relatively low percentage of ripened grains as compared with the other leading varieties. Therefore, these studies were aimed to finding out of some measures for the improvement of ripening in rice. The studies had been carried out in the field and in the phytotron during the period of three years from 1970 to 1972 at the Crop Experiment Station in Suwon. The results obtained from the experiments could be summarized as follows: 1. The spikelet of Tongil was longer in length, more narrow in width, thinner in thickness, smaller in the volume of grains and lighter in grain weight than those of Jinheung. The specific gravity of grain was closely correlated with grain weight and the relationship with thickness, width and length was getting smaller in Jinheung. On the other hand, Tongil showed a different pattern from Jinheung. The relationship of the specific gravity with grain weight was the greatest and followed by that with the width, thickness and length, in order. 2. The distribution of grain weight selected by specific gravity was different from one variety to another. Most of grains of Jinheung were distributed over the specific gravity of 1.12 with its peak at 1.18, but many of grains of Tongil were distributed below 1.12 with its peak at 1.16. The brown/rough rice ratio was sharply declined below the specific gravity of 1.06 in Jinheung, but that of Tongil was not declined from the 1.20 to the 0.96. Accordingly, it seemed to be unfair to make the specific gravity criterion for ripened grains at 1.06 in the Tongil variety. 3. The increasing tendency of grain weight after flowering was different depending on varieties. Generally speaking, rice varieties originated from cold area showed a slow grain weight increase while Tongil was rapid except at lower temperature in late ripening stage. 4. In the late-tillered culms or weak culms, the number of spikelets was small and the percentage of ripened grains was low. Tongil produced more late-tillered culms and had a longer flowering duration especially at lower temperature, resulting in a lower percentage of ripened grains. 5. The leaf blade of Tongil was short, broad and errect, having light receiving status for photosynthesis was better. The photosynthetic activity of Tongil per unit leaf area was higher than that of Jinheung at higher temperature, but lower at lower temperature. 6. Tongil was highly resistant to lodging because of short culm length, and thick lower-internodes. Before flowering, Tongil had a relatively higher amount of sugars, phosphate, silicate, calcium, manganese and magnesium. 7. The number of spikelets of Tongil was much more than that of Jinheung. The negative correlation was observed between the number of spikelets and percentage of ripened grains in Jinheung, but no correlation was found in Tongil grown at higher temperature. Therefore, grain yield was increased with increased number of spikelets in Tongil. Anthesis was not occurred below 21$^{\circ}C$ in Tongil, so sterile spikelets were increased at lower temperature during flowering stage. 8. The root distribution of Jinheung was deeper than that of Tongil. The root activity of Tongil evaluated by $\alpha$-naphthylamine oxidation method, was higher than that of Jinheung at higher temperature, but lower at lower temperature. It is seemed to be related with discoloration of leaf blades. 9. Tongil had a better light receiving status for photosynthesis and a better productive structure with balance between photosynthesis and respiration, so it is seemed that tongil has more ideal plant type for getting of a higher grain yield as compared with Jinheung. 10. Solar radiation during the 10 days before to 30 days after flowering seemed enough for ripening in suwon, but the air temperature dropped down below 22$^{\circ}C$ beyond August 25. Therefore, it was believed that air temperature is one of ripening limiting factors in this case. 11. The optimum temperature for ripening in Jinheung was relatively lower than that of Tongil requriing more than $25^{\circ}C$. Air temperature below 21$^{\circ}C$ was one of limiting factors for ripening in Tongil. 12. It seemed that Jinheung has relatively high photosensitivity and moderate thermosensitivity, while Tongil has a low photosensitivity, high thermosensitivity and longer basic vegetative phase. 13. Under a condition of higher nitrogen application at late growing stage, the grain yield of Jinheung was increased with improvement of percentage of ripened grains, while grain yield of Tongil decreased due to decreasing the number of spikelets although photosynthetic activity after flowering was. increased. 14. The grain yield of Jinheung was decreased slightly in the late transplanting culture since its photosynthetic activity was relatively high at lower temperature, but that of Tonil was decreased due to its inactive photosynthetic activity at lower temperature. The highest yield of Tongil was obtained in the early transplanting culture. 15. Tongil was adapted to a higher fertilizer and dense transplanting, and the percentage of ripened grains was improved by shortening of the flowering duration with increased number of seedlings per hill. 16. The percentage of vigorous tillers was increased with a denser transplanting and increasing in number of seedlings per hill. 17. The possibility to improve percentage of ripened grains was shown with phosphate application at lower temperature. The above mentioned results are again summarized below. The Japonica type leading varieties should be flowered before August 20 to insure a satisfactory ripening of grains. Nitrogen applied should not be more than 7.5kg/10a as the basal-dressing and the remained nitrogen should be applied at the later growing stage to increase their photosynthetic activity. The morphological and physiological characteristics of Tongil, a semi-dwarf, Indica $\times$ Japonica hybrid variety, are very different from those of other leading rice varieties, requring changes in seed selection by specific gravity method, in milling and in the cultural practices. Considering the peculiar distribution of grains selected by the method and the brown/rough rice ratio, the specific gravity criterion for seed selection should be changed from the currently employed 1.06 to about 0.96 for Tongil. In milling process, it would be advisable to bear in mind the specific traits of Tongil grain appearance. Tongil is a variety with many weak tillers and under lower temperature condition flowering is delayed. Such characteristics result in inactivation of roots and leaf blades which affects substantially lowering of the percentage of ripened grains due to increased unfertilized spikelets. In addition, Tongil is adapted well to higher nitrogen application. Therefore, it would be recommended to transplant Tongil variety earlier in season under the condition of higer nitrogen, phosphate and silicate. A dense planting-space with three vigorous seedlings per hill should be practiced in this case. In order to manifest fully the capability of Tongil, several aspects such as the varietal improvement, culural practices and milling process should be more intensively considered in the future.he future.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.720-732
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• 1995

The use of transforming growth $factor-{\beta}1$ which functions as a potent biologic mediator regulating numerous activities of wound healing has been suggested for the promotion of periodontal regeneration. The mitogenic effects of transforming growth $factor-{\beta}1$ on human periodontal ligament cells and human gingival fibroblasts were evaluated by determining the incorporation of $[^3H]-thymidine$ into DNA of the cells dose-dependently. Cells were prepared with primary cultured fibroblasts and periodontal ligament cells from humans, and used in experiments were the fourth or sixth subpassage. Cells were seeded with serum free Dulbecco's modified Eagle medium containing 0.1% bovine serum albumine. The added concentrations of transforming growth $factor-{\beta}1$ were 0.25, 0.5, 1, 2.5, 5ng/ml and transforming growth $factor-{\beta}1$ were added to the quiescent cells for 24hours, 48hours, 72hours. They were labeled with lnCi/ml $[^3H]$ thymidine for the last 24hour of the each culture. The results were presented as the mean counts per minute (CPM) per well and S.D. of four determinations. The results were as follows. : The DNA synthetic activity of human gingival fibroblasts was increased dose-dependently by transforming growth $factor-{\beta}1$ at 24 hours, 48 hours and 72 hours. The maximum mitogenic effects were at the 48 hour application of transforming growth $factor-{\beta}1$. The DNA synthetic activity was generally more decreased at the 72 hour application than at the 48 hour the application of transforming growth $factor-{\beta}1$. The DNA synthetic activity of human periodontal ligament cells was increased dose-dependently by transforming growth $factor-{\beta}1$ at 24 hours and 48 hours. But the DNA synthetic activity was decreased at 5ng/ml of the 72 hour application. The maximum mitogenic effects were also at the 48 hour application of transforming growth $factor-{\beta}1$. The DNA synthetic activity of human periodontal ligament cells was generally more decreased at the 72 hour application than at the 48 hour application of transforming growth $factor-{\beta}1$. In the comparision of DNA synthetic activity between the human gingival fibroblasts and human periodontal ligament cells, the human gingival fibroblasts had more activity than the human periodontal ligament cells at all time application with the concentration of transforming growth $factor-{\beta}1$. In conclusion, transforming growth $factor-{\beta}1$ has an important roles in the stimulation of DNA synthesis in human periodontal ligament cells and human gingival fibroblasts, which means an increase in collagen synthesizing cells and thus, may be useful for clinical application in periodontal regenerative procedures.

• Journal of Distribution Research
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• v.17 no.3
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• pp.1-24
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• 2012

Franchises have recently emerged as the most rapidly expanding industry positioned to create a large impact in the domestic economic. The Chinese franchise industry developed rapidly in the period prior and subsequent to WTO accession with more than 50% of new franchises brands emerging since 2000. M&A transactions in the Chinese franchise industry have progressed actively. In the period from 2005-2007, due to the wholesale and retail market opening in accordance with the guidelines laid forth within the MOU by the WTO the Chinese franchise market is now the largest market in the world all despite a short history of only 20 years. The amount of franchise market research on China is disproportional to its current size and development potential. Beginning in the 1990s, market research conducted by the International Franchise Association focused on emerging markets in Eastern Europe and China. While the research dealt with the Chinese investment environment, it insufficiently explained the market region and cultural environment. The purpose of this research is (i) to investigate the determinants of the performance of franchise systems in China and (ii) new contract renewals based on performance factors. This study will complement existing research in terms of the franchisee perspective. This study may also prove of the benefit to the franchise companies entering the Chinese franchise market enabling them to develop an effective strategy. This study shows that support, incentives, and system standardization by franchisor yielded a positive effect on management performance. This is consistent with previous studies by Shin (2000) and Kim (2008) targeting Korean franchises. Therefore, in the Chinese market, the franchisor must focus on support, incentives, and system standardization rather than concentrate only on the recruitment of franchisees in order to improve revenue. Hypotheses regarding franchisor control have been dismissed in existing research, in the opinion of this study, due to their complexity and inability to control the merchant as a one-kind-assessment-standard. Our findings show that the franchisees' financial condition, management ability and entrepreneurial spirit, among franchisee's characteristics, have a positive effect on franchisor's business performance and satisfaction for the franchisee. This is consistent with previous studies on headquarters' management performance of Lussier (1996), Heo and Jang (2008), and franchisees' financial condition, management ability and entrepreneurial spirit effect on franchisor's satisfaction of Weaven and Franzer (2007), Kim (2009), Han (2009), and Yoon etc. (2008). Therefore, when permitting a franchisee, financial condition, management ability, entrepreneurship of the franchisee should be carefully considered. Among relational factors between franchisor and franchisee, trust has the positive influence on the management performance of the franchisor while conflict has a negative effect. However, trust, commitment and conflict factors have been shown not to have any impact on the satisfaction of the franchise headquarters. This result is consistent with the previous studies of Pavlou and Ba (2000), Morrison (1999), Weaven and Frazer (2007), Kim and Park (1994), Sohn (2007) which show that trust between franchisor and the franchisees have a positive effect and that conflict has a negative impact on franchisor's management performance. Other factors causing a negative effective on the franchisor's management performance are a rapid environmental changes and uncertainty in the business. This is consistent with Campbell et al (2007), Kim and Kim (2009), Han and Baek (2008). Finally, the high management performance and satisfaction of the franchise headquarters has a positive effect on the intention of franchise renewal. In the case of large markets such as China, the franchisor's strategy and the role is very important. In this study, we also investigated the characteristics of franchisor and franchisee, relationship, and environmental uncertainty affecting on the management performance and satisfaction of franchisor. Recently, Korean franchises are attempting to enter foreign markets through the rise in popularity of Korean culture and entertainment commonly referred to as the Korean wave. This study provides recommendations for Korean franchises intending on entering the Chinese market. First, in order to achieve stable profits, the franchise corporation needs to support the operation of the individual franchisee through incentives and standardization of services. Second, because trust between the franchisor and franchisee has a positive effect on management performance, on-going discussion and cooperation is necessary to reduce the level of conflict.