• Journal of the Korean Geographical Society
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• v.29 no.3
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• pp.297-317
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• 1994

This study demonstrates the changes in the spatial organization of Korea by the construction of Seoul-Pusan railroad. This Seoul-Pusan line, which is the most important one in Korea was constructed in 1905. The original plan of the line was selected to cross the main traditional roads to control the entire Korean peninsular and to mobilize the Korean commercial potentials. It was the line to exploit the staples and to expand the Japanese market in Korea. In accordance with the contracts between Japan and Korean government, Korean government had to supply the lands for railroad, office, and service facilities. That was one of the important reasons that Korean government had been broken down. The main findings of this study are as follows: 1. The Seoul-Pusan railroad line was constructed Japanese colonial policy which emphasized three main purposes; the first was to reorganize the economic space and to collapse the traditional Korean markets for Japanese ruling, and the second was to find out the military supply routes, and the third was to search for the transcontinental line for China and Siberia. As the results, the old Korean pedestrian routes, which were the Eastern, the mid, the westren, and the Samnam route lost their functions. 2. Japanese requested for Korean government usually ten times of wider space for the site of stations than the needed one. The land was expropriated, and constructed the new centers aparted from the original Korean towns. In this process Japanese got the most developmental and windfall profits. The newly constructed centers were for Japanese immigration and the town service facilities which would be used to control the Korean financial market. At last, they easily converted the Korean spatial economy into Japanese colonial one, which made to reinforce the sphere of Seoul-Pusan line. 3. Japanese planned the stations as the central points in Korea. So the railroad stations were located apart from the centers of towns, to avoid the Korean resistances, and to maximize their profits. The mean distance from staiton to 'the town center is about 1km while the Japanese case is 0.6km. 4. The pattern of present Korean railroads is not the 'X type'. Because the Honam line is not the trunk one. So, we could call the Korean railroad pattern as the 'Ip(Chinese character 入) type' . The operational effects of Seoul-Pusan line brought out the concentration of the national economy to this line as Japanese planned. And the polorization had occurred between this line and the other parts of Korea. For twenty years (1910-1930), the transported freights were increased about 5 times. In 1930, the total freight of Seoul-Pusan line became 2, 010, 444 metric tons. If we examine this process, the underconstructing Seoul-Pusan express electric railroad should avoid adjacent this line to reduce the regional and ecological imbalance. 5. The forms of centers on the Seoul-Pusan line were classified into six types in relation to station, town center, and built-up area; the compact (integrated) type, the elongated one, the splited (independent) one, the absorbed one, the consolidated one, and the declined one. All types of these towns might be developed in accordance with the centrality, railroad function, and the other transportational functions. 6. The Seoul-Pusan line plays the most important role among Korean railroads but the ratio of passenger and freight become lower because the effiects of other inaugurated railoads the different transportation modes such as trucks and cars would be got more merits in competition. 7. The results of cluster analyses on the cities of railroad stations showed the rudimentary urban systems in 1910 and 1930. In 1930, the cities were classified into three groups; the group of small cites, the intermediate (developing) city-group, and the special city-group. In 1930s the spatial organization and urban system of Korea were similar to the present ones. We call appreciate that these were the effects of the Seoul-Pusan line.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.293-300
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• 2017

This study was designed to extracts from Orostachys japonicas were investigated to assess anti-oxidation and biological activity. Phenolic content was maximum of $10.56{\pm}0.32mg/g$ when extracted with 50% ethanol. In anti-oxidative activity, Orostachys japonicus electric donating activity was higher than 80% in both water and ethanol extract at $200{\mu}g/mL$. 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization of both water and ethanol extract was higher than 95.0% but antioxidant protection factor of water extract was higher than ethanol extract. Thiobarbituric acid reactive substance of ethanol extract was higher than water extract. For antihypertensive effect determination, angiotesin converting enzyme of water and ethanol extract showed 6.67 and 7.98% each at $200{\mu}g/mL$. Ethanol extract of $200{\mu}g/mL$ showed xanthin oxidase inhibitory effect of 60.85% but was not shown with water extract. Orostachys japonicus ethanol extract showed higher tyrosinase inhibitory activity of 64.59% which was higher than kojic acid of control indicating higher whitening effect. In anti-wrinkle effect, ethanol extract at $50-200{\mu}g/mL$ showed collagenase inhibitory effect of 75.95-85.02% which was higher than 68.91-76.64% of epigallocatechin-gallate of control group. 50% ethanol extract showed higher elastase inhibitory activity than water extract. Therefore, Orostachys japonicus extracts were identified to have high anti-wrinkle effect. These results identify anti-oxidative activity, gout prevention, whitening effect, and anti-wrinkle effect which indicate the possibility as a source for functional material.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.435-444
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• 2009

Statement of problem: The clinical use of electric and electomagnetic fields for fracture healing applications began in the early 1970s. Since then, several technologies have been developed and shown to promote healing of fractures. Developments of these devices have been aided in recent years by basic research and several well controlled clinical trials not only in the medical field but in dentistry. Purpose: The purpose of this study was to compare alveolar bone reduction following immediate implantation using implants onto which magnets were attached in fresh extracted sockets. Material and methods: Four mongrel dogs were involved. Full buccal and lingual mucoperiosteal flaps were elevated and third and fourth premolars of the mandible were removed. Implants with magnets and implants without magnets were installed in the fresh extracted sockets and after 3 months of healing the animals were sacrificed. The mandibles were dissected and each implant sites were sampled and processed for histological examination. Results: The marginal gaps that were present between the implant and walls of the sockets at the implantation stage disappeared in both groups as a result of bone fill and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12 week interval the mean of marginal bone resorption in the control group was significantly higher than that of the magnet group. The majority of specimens in magnet group presented early bone formation and less resorption of the buccal marginal bone compared to the control group. Conclusion: Within the limitations of this study, it could be concluded that implants with magnets attached in the early stages of implantation may provide more favorable conditions for early bone formation and reduce resorption and remodeling of marginal bone.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.179-190
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• 2012

This study was performed to obtain a heat saving effect and enhance the efficiency of a greenhouse by using a hot water piping in order to minimize the operating costs of a greenhouse as oil prices continue to rise. This method also reduces the likelihood of accidents caused by snowdrifts in regions with heavy snowfall. In general, the experimental plot was $2.0{\sim}6.0^{\circ}C$ higher than the control plot. When the skylight felt was opened, the minimum temperature was in the range of $3.0{\sim}12.0^{\circ}C$. Therefore, we judged that damage caused by snowdrifts may be prevented partly by active heating. The temperature difference inside of the greenhouse by height was insignificant. The maximum heating load of the greenhouse according to crop was respectively about $37,000kcal{\cdot}h^{-1}$ and $41,700kcal{\cdot}h^{-1}$. During the experiment, the heat value of each designed temperature in the range of the minimum ambient temperature $-11.9{\sim}4.0^{\circ}C$ was about 95,000~322,000 kcal and it was in the range of $6,050{\sim}20,900kcal{\cdot}h^{-1}$. If it is compared with the maximum heating load, it can be shown that about 15~56% of the heating energy can be supplied. The total heat value and the amount of power consumption were 2,629,025 kcal and 677.3 kWh respectively during the experiment. If it is heated with diesel, a fossil fuel, the consumption during the experiment was 291 L and the cost was 331,700won. Total cost of using electric power was about 24,400 won and it is shown that it is about 7.5% of the cost of diesel consumption. Also, if the total amount of power consumption is converted into energy, it is approximately 582,200 kcal and the energy was just about 22% of the total heat value.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.15-25
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• 2023

In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO₂-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm^-1. Such enhancement in ER performance of SiO₂-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.227-238
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• 2013

The purpose of this study is to develop a process technology to produce high hardness drinking water which meet drinking water standard, remaining useful minerals like magnesium and calcium in the seawater desalination process while removing the sulfate ions and chloride ions. Seawater have been separated the concentrated seawater and desalted seawater by passing on Reverse Osmosis membrane (RO). Using Nano-filtration membrane (NF), We were prepared primary mineral concentrated water that sodium chloride were not removed. By the operation of electro-dialysis (ED) having ion exchange membrane, we were prepared concentrated mineral water (Mineral enriched desalted water) which the sodium chloride is removed. We have produced the high hardness water to meet the drinking water quality standards by diluting the mineral enriched desalted water with deionized water by RO. Reverse osmosis membranes (RO) can separate dissolved material and freshwater from seawater (deep seawater). The desalination water throughout the second reverse osmosis membrane was completely removed dissolved substances, which dissolved components was removed more than 99.9%, its the hardness concentration was 1 mg/L or less and its chloride concentration was 2.3 mg/L. Since the nano-filtration membrane pore size is $10^{-9}$ m, 50% of magnesium ions and calcium ions can not pass through the nano-filtration membrane, while more than 95% of sodium ions and chloride ions can pass through NF membrane. Nano-filtration membrane could be separated salt components like sodium ion and chloride ions and hardness ingredients like magnesium ions and calcium ions, but their separation was not perfect. Electric dialysis membrane system can be separated single charged ions (like sodium and chloride ions) and double charged ions (like magnesium and calcium ions) depending on its electrical conductivity. Above electrical conductivity 20mS/cm, hardness components (like magnesium and calcium ions) did not removed, on the other hand salt ingredients like sodium and chloride ions was removed continuously. Thus, we were able to concentrate hardness components (like magnesium and calcium ions) using nano-filtration membrane, also could be separated salts ingredients from the hardness concentration water using electrical dialysis membrane system. Finally, we were able to produce a highly concentrated mineral water removed chloride ions, which hardness concentration was 12,600 mg/L and chloride concentration was 2,446 mg/L. By diluting 10 times these high mineral water with secondary RO (Reverse Osmosis) desalination water, we could produce high mineral water suitable for drinking water standards, which chloride concentration was 244 mg/L at the same time hardness concentration 1,260 mg/L. Using the linked process with reverse osmosis (RO)/nano filteration (NF)/electric dialysis (ED), it could be concentrated hardness components like magnesium ions and calcium ions while at the same time removing salt ingredients like chloride ions and sodium ion without heating seawater. Thus, using only membrane as RO, NF and ED without heating seawater, it was possible to produce drinking water containing high hardness suitable for drinking water standard while reducing the energy required to evaporation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.353-360
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• 1984

As an effort to expand the utilization of mackerel which has been thought disadvantageous to processors due to the defects in bloody dark color of meat, high content of lipid, and low stability of protein, and to develope a new type of product, so called, preservative fish meat paste, the processing method was studied in which dielectric heating was applied by means of cooking, pasteurization, dehydration, and control of water activity. The principle of this method is based on that dielectric heating can initiate a rapid dispersion or displacement of moisture in the meat tissue so that the level of water acivity can be controlled by dehydration with hot air meanwhile the product is cooked, pasteurized, and texturized. And the product is finally heated with electric heaters and vacuum sealed to stabilize water activity and storage stability. In present paper, a formula for preparing the fish meat-stach paste, the conditions of dielectric heating and dehydration, shape and size of the product, and other parameters were tested to optimize the process operation. A formula of the fish meat-starch paste to provide proper textural properties and water activity was $10\%$ starch, $1.5\%$ salt, $3\%$ soybean, $0.6\%$ MSG, $2\%$ sucrose, and $3\%$ sorbitol against the weight of fish meat. A proper shape and size of the product to avoid foaming and case hardening during heating was sliced disc of 8 cm $diameter{\times}0.8$ cm thickness or $10{\times}10$ cm square plate with 1.0 cm thickness. The disc shape was recommended because it resulted more uniform heating, minimum foaming and case hardening. And it was also advantageous that disc was simply provided when the fish meat disc was stuffed in the same, solidified in boiling water for 2 to 3 minutes, and sliced. Condition of dielectric heating was critical to decide the levels of sterility, water activity, and textural property of the product. The temperature at the center of the meat disc slices was raised up to $95^{\circ}C$ in 1.5 minutes so that continuous exposure to microwave caused expanded tissue and hardening ending up with a higher water content. Heating for 5 to 6 minutes was adequate to yield the final water activity of 0.86 to 0.83(35 to $40\%$ moisture). It is important, however, that heating had to be done periodically, for instance, in the manner of 2.0, 1.5, 1.5, and 1.0 minute to give enough time to displace or evaporate moisture from the meat tissue. The product was dehydrated for 2 to 3 minutes by hot air of $60^{\circ}C$, 3 to 5m/sec and finally exposed to electric heaters for 5 to 6 minutes until the surface was roasted deep brown. These conditions of heating and dehydration resulted in a complete reduction of total plate count from an initial count of $5.3{\times}10^6/g$ to less than $3{\times}10^2/g$. General composition of the product was $40.1\%$ moisture, $20.8\%$ protein, $17.4\%$ lipid, $16.2\%$ carbohydrate, and $5.5\%$ ash. Textural properties revealed folding test AA, hardness 42, cohesiveness 0.53, toughness 4.6, and elasticity 0.8.

• Journal of Forest and Environmental Science
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• v.21 no.1
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• pp.34-58
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• 2005

This study was executed to find out how to improve the planting and use of landscaping plants in Weonju and Hoengseong. 1. The number of street trees were 22,068 and the species number were 10 species in Weonju in 2004. The major species of street trees were Ginkgo biloba(58%), Prunus sargentii(15%), Zelkova serrata(9%), Prunus armeniaca var. ansu(8%), and Acer palmatum(6%). The ratio of native species versus exotic were 50:50. In Hoengseong, the number of street trees was 13,500 and the species number were 15 species. The major species of street trees were Prunus sargentii(42%), Ginkgo biloba(23%), Acer triflorum(12%), Prunus armeniaca var. ansu(6%), and Prunus mume(4%). The ratio of native species versus exotic were 67:33. The species of which planting frequency within two areas was very high were Ginkgo biloba and Prunus sargentii. 2. It is necessary to select tree species suitable for the characteristics of the locality and to raise distinctive street trees that contribute to the tourist industry. For the purpose, the appropriate street trees in two areas are Cornus controversa, Quercus aliena, Zelkova serrata, Prunus padus, Sorbus alnifolia, Sorbus comixta, Albizzia julibrissin, Acer triflorum, Styrax japonica, Chionanthus retusus, Celtis sinensis, Prunus yedoensis, Malus sieboldii, Crataegus Pinnatifida, Prunus armeniaca var. ansu and Pyrus pyrifolia etc.. 3. Appropriate pruning adds to the aesthetic and prolongs the useful life, it also requires less managing of insects and diseases to maintain good healthy of street trees. Street trees were not properly pruned due to electric lines and shortage of pruning information. The pruning was controlled by Korea Electric Power Co, which has no pruning information. Pruning must be maintained by a professional landscape company to maintain good shape such as with Bonsai. The shrubs planting zone between street trees and other trees, and preservation plates were established for healthy of street trees. They have to be repaired and maintained well to keep better environmental conditions. The proper fertilization, the control of pests and diseases, the installation of drainpipe and the use of soil brought from another place were needed to improve the planting, use and maintenance of landscape plants. 4. The species number of school trees and flowers of 102 schools in Weonju and Hoengseong were 17species, 16species respectively. The major species of school trees in Weonju were Juniperus chinensis(24%), Ginkgo biloba(17%), Pinus densiflora(14%), Zelkova serrata(14%), and Pinus koraiensis(9%), and those of school trees in Hoengseong were Pinus koraiensis(44%), Abies holophylla(25%), Juniperus chinensis(8%), and Ginkgo biloba(8%). The major species of school flowers in Weonju were Rosa centifolia(47%), Forsythia koreana(24%), Magnolia kobus(12%), and Rhododendron schlippenbachii(6%), and those of school flowers in Hoengseong were Forsythia koreana(36%), Rhododendron schlippenbachii(33%), Magnolia kobus(6%) and Dicentra spectabilis(6%). 5. The species number of the protection trees designated by Woenju and Hoengseong were 15 species. The major species of protection trees were Zelkova serrata(100 trees), Ginkgo biloba(18) Pinus densiflora(7), Quercus spp. (5), Juniperus chinensis(4) and Alnus japonica(4). 6. The landscape plants planted around 2004 in weonju were Prunus yedoensis(2,563 trees), Betula platyphylla var. japonica(2,000), Abies holophylla(1,785), Diospyros kaki(1,100), Prunus sargentii(880) and Prunus armeniaca var. ansu(708) etc.. The shrubs planted were Rhododendron obutusum(21,559 plants), Rosa centifolia (7,150), Rhododendron yedoense var. poukhanense(5,950), Forsythia koreana(3,000) and Ligustrum obtusi[olium(2,500) etc.. The landscape plants planted in Hoengseong Acer triflorum(928trees), Prunus yedoensis(455), Zelkova serrata(327), Thuja orientalis(261), Prunus sargentii(257), Pinus koraiensis(200), Prunus persica for. rubro-plena(200) and Pyrus pyrifolia (200) etc.. The shrubs planted were Rhododendron yedoense var. poukhanense(15,936), Syringa dilatata(10,090), Forsythia koreana(9,660), Cercis chinensis(3,200), Buxus microphylla var. koreana(2,600) and Rosa centifolia(1,868) etc.. 7. The species numbers of the herbaceous plants planted in 2004 in Weonju were 24 species and the ratio of native species versus exotic were 7:17. The major species of perennial plants were Aster koraiensis(30,656 plants), Coreopsis drummondii(7,656), Rudbeckia bicolor(6,000), Chrysanthemum morifolium(4,850) and Chrysanthemum zawadskii var. latilobum(4,312). The major species of annuals and biennials were Cosmos bipinnatus(672,000 plants), Zinnia elegans(35,600), Petunia hybrida(26,920), Viola tricolor(23,000), Helianthus annuus(17,000), and Geranium cinereum var. pubcaulescens(5,200). In Hoengseong, the numbers of herbaceous plants were 906,310 plants and the species numbers were 15 species. The major species of perennials plants were Aster koraiensis(70,480 plants), Hemerocallis fulva(20,070), and Phlox drummondii(18,000). The major species of annuals and biennials were Phlox hybrida(174,000 plants), Cosmos bipinnatus(125,000), Zinnia elegans(109,000), Tagetes patula(96,700), Vinca rosea(89,000) and Calendula officinalis(70,000). 8. Through these result, it was thought that the diversification of planting species, the selection of plants suitable to each space and the generalization of use of native species were needed.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.151-169
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• 1993

The present study was carried out to investigate the best condition for nuclear-cytoplasm fusion and in vitro culture of nuclear transplanted embryos and to investigate the production of nuclear transplanted offsprings. The nuclei from 2-, 4- and 8-cell mouse embryos were transferred into enucleated 2-cell embryos, and the reconstituted embryos were submitted to direct current(DC) pulses at output voltage of 1.0, 1.5 and 2.0 kV/cm for 100, 150 and $200{\mu}$ sec to induce cell fusion. 1. The culture of intact or zona cut 2-cell embryos in the medium supplemented with cytochalasin B($5{\mu}g/m{\ell}$) and colcemide($0.1{\mu}g/m{\ell}$)for 30 and 60 minutes did not affect the development to later stage. 2. The in vitro developmental rates of group A(a nucleus from one of the blastomeres was removed) and B(electrofusion of group A) were significantly lower than that of control group(p<0.01). 3. When nuclear transplanted embryos were submitted to electrofusion, the significantly higher fusion rates of 2-cell donor nuclei were achieved at the electric field strength of DC 1.5kV/cm for 100 and $150{\mu}$ sec, DC 2.0 kV/cm for $100{\sim}200{\mu}$ sec than DC 1.0 kV/cm for 100 and $150{\mu}$ sec(p<0.01). The significantly higher fusion rates of 4-cell donor nuclei were achieved at DC 2.0 kV/cm for 100 and $150{\mu}$ sec than DC 1.0kV/cm for $100{\sim}200{\mu}$ sec(p<0.01). These fusion rates in 8-cell donor nuclei were 88.7~99.3%. 4. The developmental potency to blastocyst in 2- and 4-cell donor nuclei was significantly higher in DC 1.0 and 2.0 kV/cm for $100{\sim}200{\mu}$ sec treated group and DC 2.0 kV/cm for 150 and $200{\mu}$ sec treated group (p<0.01). The developmental potency to blastocyst in 8-cell donor nuclei was significantly higher in DC 2.0 kV/cm for $100{\mu}$ sec treated group than in DC 1.0 kV/cm for $100{\mu}$ sec treated group and DC 2.0 kV/cm for 150 and $200{\mu}$ sec treated group(p<001). 5. The developmental potency to blastocyst after nuclear transplantation was significantly higher in 2-cell donor nuclei than in 8-cell donor nuclei(p<0.01). 6. The success rate of nuclear injection into enucleated 2-cell embryos was significantly higher in 2-cell donor nuclei than in 4- or 8-cell donor nuclei(p<0.01). 7. The culture time taken for the nuclear transplanted 2-cell embryos to blastocyst stage was significantly longer in 2-cell donor nuclei than in 8-cell donor nuclei(p<0.01). 8. There was no significant difference in the developmental potency of nuclear transplanted embryos within the concentration of EGF at 0 to 15 ng per $m{\ell}$ of BMOC-3 solution. 9. The production rates of offspring after transfer of nuclear transplanted embryos to recipient mouse were significantly higher in 2-cell donor nuclei than in 8-cell donor nuclei(p<0.01).

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.27-47
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• 1992

Engineers have developed new instruments that aid in diagnosis and therapy Ultrasonic imaging has provided a nondamaging method of imaging internal organs. A complex transducer emits ultrasonic waves at many angles and reconstructs a map of internal anatomy and also velocities of blood in vessels. Fast computed tomography permits reconstruction of the 3-dimensional anatomy and perfusion of the heart at 20-Hz rates. Positron emission tomography uses certain isotopes that produce positrons that react with electrons to simultaneously emit two gamma rays in opposite directions. It locates the region of origin by using a ring of discrete scintillation detectors, each in electronic coincidence with an opposing detector. In magnetic resonance imaging, the patient is placed in a very strong magnetic field. The precessing of the hydrogen atoms is perturbed by an interrogating field to yield two-dimensional images of soft tissue having exceptional clarity. As an alternative to radiology image processing, film archiving, and retrieval, picture archiving and communication systems (PACS) are being implemented. Images from computed radiography, magnetic resonance imaging (MRI), nuclear medicine, and ultrasound are digitized, transmitted, and stored in computers for retrieval at distributed work stations. In electrical impedance tomography, electrodes are placed around the thorax. 50-kHz current is injected between two electrodes and voltages are measured on all other electrodes. A computer processes the data to yield an image of the resistivity of a 2-dimensional slice of the thorax. During fetal monitoring, a corkscrew electrode is screwed into the fetal scalp to measure the fetal electrocardiogram. Correlations with uterine contractions yield information on the status of the fetus during delivery To measure cardiac output by thermodilution, cold saline is injected into the right atrium. A thermistor in the right pulmonary artery yields temperature measurements, from which we can calculate cardiac output. In impedance cardiography, we measure the changes in electrical impedance as the heart ejects blood into the arteries. Motion artifacts are large, so signal averaging is useful during monitoring. An intraarterial blood gas monitoring system permits monitoring in real time. Light is sent down optical fibers inserted into the radial artery, where it is absorbed by dyes, which reemit the light at a different wavelength. The emitted light travels up optical fibers where an external instrument determines O2, CO2, and pH. Therapeutic devices include the electrosurgical unit. A high-frequency electric arc is drawn between the knife and the tissue. The arc cuts and the heat coagulates, thus preventing blood loss. Hyperthermia has demonstrated antitumor effects in patients in whom all conventional modes of therapy have failed. Methods of raising tumor temperature include focused ultrasound, radio-frequency power through needles, or microwaves. When the heart stops pumping, we use the defibrillator to restore normal pumping. A brief, high-current pulse through the heart synchronizes all cardiac fibers to restore normal rhythm. When the cardiac rhythm is too slow, we implant the cardiac pacemaker. An electrode within the heart stimulates the cardiac muscle to contract at the normal rate. When the cardiac valves are narrowed or leak, we implant an artificial valve. Silicone rubber and Teflon are used for biocompatibility. Artificial hearts powered by pneumatic hoses have been implanted in humans. However, the quality of life gradually degrades, and death ensues. When kidney stones develop, lithotripsy is used. A spark creates a pressure wave, which is focused on the stone and fragments it. The pieces pass out normally. When kidneys fail, the blood is cleansed during hemodialysis. Urea passes through a porous membrane to a dialysate bath to lower its concentration in the blood. The blind are able to read by scanning the Optacon with their fingertips. A camera scans letters and converts them to an array of vibrating pins. The deaf are able to hear using a cochlear implant. A microphone detects sound and divides it into frequency bands. 22 electrodes within the cochlea stimulate the acoustic the acoustic nerve to provide sound patterns. For those who have lost muscle function in the limbs, researchers are implanting electrodes to stimulate the muscle. Sensors in the legs and arms feed back signals to a computer that coordinates the stimulators to provide limb motion. For those with high spinal cord injury, a puff and sip switch can control a computer and permit the disabled person operate the computer and communicate with the outside world.