• Korean Journal of Animal Reproduction
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• v.27 no.2
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• pp.125-133
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• 2003

The present study was carried out to examine the effect of $\beta$-Mercaptoethanol ($\beta$-ME) on in vitro maturation (IVM) of porcine follicular oocytes and oxygen concentration with $\beta$-ME on in vitro development (IVD) of porcine IVM/IVF embryos. The results were summarized as follows. 1. The rates of nuclear maturation, penetrated oocytes, polyspermic oocytes, pronucleus formation and mean numbers of the penetrated sperms were not significantly different using NCSU-23 maturation media for 0, 25, 50 and 100 $\mu$M $\beta$-ME (P>0.05). 2. The rates of blastocyst formation at day 7 after in vitro fertilization were higher in oocytes matured with 25 $\mu$M $\beta$-ME (25.4$\pm$0.9%) than in those matured with 0 (14.5$\pm$1.6%), 50 (17.3$\pm$1.7%) and 100 $\mu$M (12.4$\pm$1.3%) (P<0.05). However, no differences ware found in total cell numbers of blastocyst among the treatments. 3. The rates of blastocyst formation at day 7 after in vitro fertilization were higher in the NCSU-23 Culture medium With 25 $\mu$M $\beta$-ME (23.6$\pm$2.8%) than in those Cultured With 0 (15.4$\pm$4.4%), 12.5 (17.5$\pm$2.3%) and 50 $\mu$M $\beta$-ME (18.6$\pm$2.1%) Under the 5% and 20% $O_2$ Concentrations (P<0.05). However, no differences was found in total cell numbers of blastocyst among the treatments. These results suggested that the addition of 25 $\mu$M $\beta$-ME in the IVM/IVD media were effective on the porcine embryo production. However, the rates of blastocyst formation and total cell numbers of blastocyst at day 7 of porcine IVM/IVF embryos were not significantly different in the NCSU-23 culture medium under 5% and 20% 02 concentrations.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.2
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• pp.109-123
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• 2009

The aim of the study was to assess the influence of insertion torque of bone quality and to compare axial force, moment and von Mises stress using finite element analysis of plastoelastic property for bone stress and strain by dividing bone quality to its thickness of cortical bone, density of trabecular bone and existence of lower cortical bone when implant inserted to mandibular premolar region. The $Br{\aa}nemark$ MKIII. RP implant and cylindrical bone finite model were designed as cortical bone at upper border and trabecular bone below the cortical bone. 7 models were made according to thickness of cortical bone, density of trabecular bone and bicortical anchorage and von Mises stress, axial force and moment were compared by running time. Dividing the insertion time, it seemed 300msec that inferior border of implant flange impinged the upper border of bone, 550msec that implant flange placed in middle of upper border and 800msec that superior border of implant flange was at the same level as bone surface. The maximum axial force peak was at about 500msec, and maximum moment peak was at about 800msec. The correlation of von Mises stress distribution was seen at both peak level. The following findings were appeared by the study which compared the axial force by its each area. The axial force was measured highest when $Br{\aa}nemark$ MKIII implant flange inserts the cortical bone. And maximal moment was measured highest after axial force suddenly decreased when the flange impinged at upper border and the concentration of von Mises stress distribution was at the same site. When implant was placed, the axial force and moment was measured high as the cortical bone got thicker and the force concentrated at the cortical bone site. The influence of density in trabecular bone to axial force was less when cortical bone was 1.5 mm thick but it might be more affected when the thickness was 0.5 mm. The total axial force with bicortical anchorage, was similar when upper border thickness was the same. But at the lower border the axial force of bicortical model was higher than that of monocortical model. Within the limitation of this FEA study, the insertion torque was most affected by the thickness of cortical bone when it was placed the $Br{\aa}nemark$ MKIII implant in premolar region of mandible.

• Journal of Technologic Dentistry
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• v.19 no.1
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• pp.21-35
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• 1997

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy is cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-20Pd-20Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electic furace and centrifugal casting machine in Ar atmoshpere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age-hardening characteristics of the small Au-containing Ag-pPd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, emergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, I. e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the Llo type face centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affedted by the Cu concentration. In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase(L1o type) and an Agrich ${\alpha}2$ phase occurred and a discontiunous precipitation occurred at the grain boundary. Form the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}\to{\alpha}+{\alpha}2+PdCu\to{\alpha}1+{\alpha}2+PdCu$ at Pd/Cu = 1 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.45-53
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• 2005

The objective of this study is to evaluate the effects of changes in soil temperature on biodegradation rate of diesel compounds from a field pilot test using hot air injection process. Total remediation time was estimated from in-situ biodegradation rate and temperature for optimum biodegradation. All tests were conducted by measuring in-situ respiration rates every about 10 days on highly contaminated area where an accidental diesel release occurred. The applied remediation methods were hot air injection/extraction process to volatilize and extract diesel compounds followed by a bioremediation process to degrade residual diesels in soils. Oxygen consumption rate varied from 2.2 to 46.3%/day in the range of 26 to $60^{\circ}C$, and maximum $O_2$ consumption rate was observed at $32.0^{\circ}C$. Zero-order biodegradation rate estimated on the basis of oxygen consumption rates varied from 6.5 to 21.3 mg/kg-day, and the maximum biodegradation rate was observed at $32^{\circ}C$ as well. In other temperature range, the values were in the decreasing trend. The first-order kinetic constants (k) estimated from in-situ respiration rates measured periodically were 0.0027, 0.0013, and $0.0006d^{-1}$ at 32.8, 41.1, and $52.7^{\circ}C$, respectively. The estimated remediation time was from 2 to 9 years, provided that final TPH concentration in soils was set to 870 mg/kg.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.9-14
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• 2005

This study was conducted to investigate the effects of Bacillus subtilis on the egg qualify, blood characteristics and fecal $NH_3-N$ in laying hens. A total of two hundred fifty two laying hens were randomly allocated into three treatments with seven replications for six weeks. Dietary treatments included 1) CON (control; basal diet), 2) BS0.2(control + $0.2\%$ Bacillus subtilis) and 3) BS0.4 (control +$0.4\%$ Bacillus subtilis). For overall Period, hen-day egg production tended to increase by the Bacillus subtilis $0.4\%$ in the diets, but was no significant difference. Egg weight, egg shell breaking strength, egg shell thickness, Haugh Unit, yolk color unit and egg yolk index were not affected by treatments. Difference of egg weight and egg shell breaking strength in the BS0.2 treatment tended to increase without significant difference. Difference of egg yolk index in laying hens fed Bacillus subtilis was increased (P<0.05). The concentrations of red blood cell (RBC) and white blood cell (WBC) were not significant difference. $NH_3-N$ concentration in feces with BS0.4 treatment was significantly (P<0.05) lower than control. In conclusion, dietary Bacillus subtilis could decrease fecal $NH_3-N$.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.201-219
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• 1989

Rice culture in Korea has a long history ranging over two thousand years. In the agriculture economy of pre-mordern Korea, however, its importantce was not as great as generally assumed. In fact, rice culture reached full development only after the 1920s when the Japanese colonial government carried out its drive to increase rice production in the Korea peninsula. It was not until the mid-1930s that rice became the staple in Korean diet. This can be attributed to two factors : (1) a mountainous topography that provides little irrigated fields and (2) a climate characterized by droughts in spring and heavy precipitation in summer. The present paper attempts to answer some of these questions. Specifically it will focus on these : Did the development of rice culture actually result in population growth? What are the salient features of agricultural develdpment and population grow in traditional Korea? Does the case of Korea conform the prevailing generalization about the agriculture in East Asia? I have discussed the development of rice culture and population growth in the Chos$\breve{o}$n dynasty, focusing on the relation between the rapid spread of transplanting and the rapid growth of population from the seventeenth to the nineteenth century. Here are my conclusions. (1) The spread of transplanting and other technological innovationsc contributed to the rapid growth of population in this period. However, we should also note that the impact of rice culture on population growth was rather limited, for rice culture was not the mainstay of agricultural economy in pre-modern Korea. Indeed we should consider the influence of dry field cropsn population growth. Nevertheless, it is obvious that the proliferation of rice culture was a factor crucial to population growth and regional concentration. (2) How should we characterize the spread of rice culture in the whole period? Evidently rice culture spread from less then 20% of cultivated fields in the fifteenth century to about 36% of them in the early twentieth century. Although rice as a single crop outweighed other crops, rice culture was more then counter-balanced by dry field crops as a whole, due to Korea's unique climate and geography. Thus what we have here in not a typical case of competition between rice culture and day field culture. Besides, the spread of rice culture in the seventeenth and eighteenth centuries accomplished by technological innovations that overcame severe springtime drought, rather than extensive irrigation. Althougt irrigarion facilities did proliferate to some extent, this was achieved by local landlords and peasants rather than the state. This fact contradicts the classical thesis that the productivity of rice culture increased through the state management of irrigation and that this in turn determined the type of society. (3) We should further study other aspects of the transition from the stable population and production struture in the fifteenth and sixteenth centuries to the rapid population growth and excessive density of population thereafter. We should note that there were continuing efforts to reclaim the land in order to solve the severe shortage of land. Changes also took place in the agricultural production relations. The increase in land producrivity developed tenancy based on rent in kind, and this in turn increased the independence of tenants from their landlords. There were changes in family relations-such as the shift to primogeniture as an effort to prevent progressive division of property among multiplying offspring. The rapid population growth also produced a great mass of propertyless farm laborers. These changes had much to do with the disintegration of traditional social institutions and political structure toward the end of the Chos$\breve{o}$n dynasty.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.2
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• pp.167-175
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• 1971

A pot experiment with an acid sulfate soil from Kimhae was carried out to find out the cause of toxicity in rice plant. The effect of liming on changes in pH, Eh, Al, and $Fe^{2+}$ in soil and leachate was examined at two-week interval during the growth of rice. Also, total $P_2O_5$, $SiO_2$, Fe and Al contents in plants at harvesting stage were determined. In the early stage, the rice plant in the check soil showed the same healthy growth as did in limed soil even at high Al in soil and leachate. Around panicle forming stage, reddish brown mottlings suddenly infested all over the plants when accompanied with strong reduction, and afterward growth was severely retarded, and finally caused the significant difference in yield. During the strong reduction, significant amount of sulfide was formed only in check soils, but no free $H_2S$ was detected. Appreciable Al was still present in soil and leachate, and $Fe^{2+}$ in check soil was lower than that in limed soil, but $Fe^{2+}$ in leachate was slightly higher. Limed soils were more reduced and produced more $Fe^{2+}$ due to increased microorganism activity in the neutral pH. In the leachate, the check showed slightly higher $Fe^{2+}$ concentration but considerably higher than limed one at later stage. Appreciable amount of Al was detected only in check soil and leachate from transplanting to panicle formation stage. Plant tissues at harvesting stage contained very low P regardless of liming. Uptake of Si was markedly increased by liming. Contents of Fe an Al was markedly higher in check than limed one, but difference in Fe content was more drastic possibly due to more Fe uptake in presence of markedly higher $Fe^{2+}$ in soil and leachate at later growing stage. In conclusion toxic symptom in this acid sulfate soil seems to be primarily due to Al when accompanied with low pH and strong reduction. But association with $Fe^{2+}$ toxicity is not completely excluded. In order to differentiate the effect of $Fe^{2+}$ from that of Al more detailed plant analysis at different stage is required.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.213-220
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• 1994

Gastrodia (G) Rhizoma has been used clinically as an oriental herbal medicine with sedative, anticonvulsive, and depressor effects. The present study tested effects of G. Rhizoma extracts on the coronary circulation and myocardial oxygen consumption in perfused rat hearts. Sprague Dawley rats (SD) and spontaneously hypertensive rats (SHR) were employed as experimental animals and nonworking Langendorff heart perfusion technique introduced for heart experiments. G. Rhizoma extracts were prepared from grinding G. Rhizoma into powder, extracting in water and 50% ethanol for 4 or 16 hr and diluting with Krebs-Henseleit bicarbonate perfusion buffer to be 70%. Hearts were perfused with bicarbonate buffer oxygenated with 95% $O_{2}:$ 5% $CO_{2}$ at constant coronary perfusion pressure of $90cmH_{2}O$. The diluted extracts were infused into coronary arteries in a concentration of $1{\sim}5\;{\mu}M$ for $7{\sim}8 min. While in SD water- or ethanol-extracts of G. Rhizoma extracted for 16 hr increased coronary perfusate flow (CPF) and decreased coronary vascular resistance (CVR), ethanol-extracts in SHR produced coronary vasoconstriction associated with enhanced CVR. G. Rhizoma extracts-induced increase in CPF reduced myocardial oxygen extraction, and thus myocardial oxygen consumption ($MVO_{2}$) remained at that observed prior to infusion of extracts. In SD and SHR 16 hr-water-extracts markedly altered coronary venous effluent pH and $Pco_{2}$ and evoked metabolic acidosis, which could be a coronary vasodilator mechanism decreasing CVR. In this study, the extracts decreasing CVR in SD and SHR did not augment the lactate production. Therefore, although the effects of the extracts on cardiac function and coronary circulation depended on solvents and duration for extraction, the 16hr-water-extracts, at least, exhibited coronary vasodilation in SD and SHR. Conversely, ethanol-extracts constricted coronary arteries in SHR. G. Rhizoma extracts-induced vasodilation might be due to the metabolic acidosis rather than due to the increased lactate production. The results indicate that G. Rhizoma extracts obtained from proper extracting procedures can be used as a safe and clinically applicable herbal medicine in the cardiovascular diseases such as coronary artery disease and hypertension for vasodilatory and antihypertensive actions.

• Economic and Environmental Geology
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• v.50 no.5
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• pp.375-387
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• 2017

Amphibolite-hosted Fe-Ti mineralization at the Soyeonpyeong Island, located in central western part of the Korean Peninsula is a typical orthomagmatic Fe-Ti oxide deposit in South Korea. The amphibolite intruded into NW-SE trending Precambrian metasedimentary rocks. Lower amphibolite is characterized by igneous layering, consisting of feldspar-dominant and amphibole-Fe-Ti oxide-dominant layers. The igneous layering shows complicated and/or sharp contact. In contrast, upper amphibolite has a more complicated lithofacies (garnet-bearing, coarser, and schistose), and massive Fe-Ti oxide ore alternates with schistose amphibolite. NS- and EW-trending fault systems lead to redistribute upper amphibolite-hosted Fe-Ti orebody and igneous layering of lower amphibolite, respectively. The whole-rock compositions of amphibolite and Fe-Ti oxide ore reflect their constituent minerals. Amphibolite shows significantly positive Eu anomalies whereas Fe-Ti oxide ore has weak negative Eu anomalies. Plagioclase (Andesine to oligoclase) and Fe-Ti oxide minerals have constant composition regardless of their distribution. Amphibole has a compositionally variable but it doesn't reflect the chemical evolution. Mineral compositions within individual layers and successive layers are relatively constant not showing any stratigraphic evolution. This suggests that there are no successive injections of Fe-rich magma or assimilation with Fe-rich country rocks. Contrasting Eu anomalies between amphibolite and Fe-Ti oxide ore also suggest that extensive plagioclase fractionation during early crystallization stage cause increase in $Fe_2O_3/FeO$ ratio and overall Fe contents in the residual magma. Thus, Fe-rich residual liquids may migrate at the upper amphibolite by filter pressing mechanism and then produce sheeted massive Fe-Ti mineralization during late fractional crystallization.

• Applied Biological Chemistry
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• v.8
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• pp.87-93
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• 1967

1) For the micro-analysis of mercury in plant materials, the method of Furutani was shown to be the simplest and most efficient way and the recovery of the assay was about 98%. 2) When the rice grain was soaked in 1/1000 diluted solution of organo-mercury fungicide for 8 hours at the end of March, the amounts of mercury residues in the brown rice and unhulled rice were 8.8 to $9.5\;{\mu}g/g$ seeds and 10.1 to $10.7\;{\mu}g/g$ seeds, respectively. 3) By washing the treated rice seeds with running water for three days, tile residual mercury concentration was reduced to 1/4 to 1/5; thus the mercury residues were 1.86 to $1.92\;{\mu}g/g$ for brown rice and 1.96 to $2.93\;{\mu}g/g$ for unhulled rice. 4) The residual mercury was present more in the unhulled rice than in the brown rice, either before or after washing of the treated seeds. 5) Among the different rice varieties, no difference was observed in mercury residues by seed treatment and washing.