• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.300-308
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• 1996

This study was conducted to identify factors involved in rooting of Japanese larch cuttings. Cuttings were taken every week from June 24th to July 25th before and after the 10th of July which supposed to be best time for cutting. The content of IAA, carbohydrate, nitrogen and inorganic elements such as $Mg^{{+}{+}}$, $K^+$ and $Ca^{{+}{+}}$ within cutting materials were analyzed. After the cuttings were planted, the root development was observed every week. Cuttings of easy-to-root clones were higher in IAA contents than the cuttings of hard-to-root clones at the time of cuttings were taken. There were significant differences in moisture content of cuttings taken on June 24th and July 25th between easy-to-root and hard-to-root clones, however no significant differences in moisture contents were observed between them taken on the 8th and 15th of July which supposed to be the best time for cutting. Inorganic matters and carbohydrate contents of cuttings taken from hedged trees were higher than those of non-hedged trees. The ratios K/C and C/N of cuttings taken from hedged trees were higher than those of non-hedged trees. Cuttings taken from easy-to-root clones showed higher content of carbohydrate and nitrogen than those of hard-to-root clones. The contents of inorganic elements, such as $Mg^{{+}{+}}$, $K^+$, and $Ca^{{+}{+}}$ in cutting taken from hard-to-root clones were slightly higher than that of easy-to-root clones. The ratio C/N and K/C of cuttings which were taken from easy-to-root clones have shown a similar trend of carbohydrate and nitrogen. These data indicate that there was no one dominant factor that affect rooting of cutting, but many factors such as contents of IAA, carbohydrate, nitrogen, phosphate, and ratios of C/N and K/C appeared to affect on rooting of cuttings variously. Most of root initials were formed from phloem tissue within one week after cutting, and few were formed from callus tissue. Root primordia were developed from root initials within two weeks after cutting, and most of new roots were developed from root primordia within about five weeks after cutting.

• Food Science and Preservation
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• v.14 no.5
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• pp.497-503
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• 2007

In order to develop a new rice bran danmooji, changes in physicochemical characteristics and texture of danmooji treated with rice bran, Stevia rebaudiana Bertoni leaf powder, succinic acid, or yeast extract were investigated during salting for 90 days. The PH of rice bran danmooji decreased from PH6.41 initially to pH 4.09 (control group), pH 4.10 (S. rebaudiana treatment S1), pH 3.84 (S. rebaudiana + succinic acid treatment S2), and pH 3.90 (S. rebaudiana+succinic acid+yeast extract treatment S3) after 90 days of salting. At this time, the salinities of rice bran danmooji of the S1, S52, and S3 groups were 2.32%, 1.94% and 2.15% respectively. The hardness of all groups decreased rapidly in the first 30 days of salting, and thereafter showed no changes. After 90 days of salting, the hardness of all groups was $1,186-1,368\;g/cm^2$ with no significant differences between groups. Redness, the a value, of the S2 and S3 groups treated with succinic acid, was lower than that of S3, whereas yellowness, the b value, of S3 treated with succinic acid and yeast extract was the highest of the three groups. Sensory evaluation of rice bran danmooji after 90 days of salting resulted in S3 attaining the highest scores for flavor, taste, texture, and overall acceptability. These results indicate nut high-quality rice bran danmooji may be prepared by addition of S. rebaudiana leaf powder, succinic acid and yeast extract to rice bran.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.1019-1037
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• 2005

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chtin. Chitosan is a derivative of chitin made by deacetylation of side chains. Chitosan has been widely studied as bone substitution and membrane material in periodontology. Many experiments using chitosan in various animal models have proven its beneficial effects. Tetracycline has been considered for use in the treatment of chronic periodontal disease and gingivitis. The aim of this study is to evlauate the osteogenesis of tetracycline blended chitosan membranes on the calvarial critical size defect in Sprague Dawley rats. An 8mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into five groups: Untreated control group versus four experimental group. Four types of membranes were made and comparative study was been done. Two types of non-woven membranes were made by immersing non-woven chitosan into either the tetracycline solution or chitosan-tetracycline solution. Other two types of sponge membranes were fabricated by immersing chitosan sponge into the tetracycline solution, and subsequent freeze-drying. The animals were sacrificed at 2 and 8 weeks after surgical procedure. The specimens were examined by histologic analyses. The results are as follows: 1. Clinically the use of tetracycline blended chitosan membrane showed great healing capacity. 2. The new bone formations of all the experimental group, non-woven and sponge type membranes were greater than those of control group. But, there was no significant difference between the experimental groups. 3. Resorption of chitosan membranes were not shown in any groups at 2 weeks and 8 weeks. These results suggest that the use of tetracycline blended chitosan membrane on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself. And it implicate that tetracycline blended chitosan membrane might be useful for guided tissue regeneration.

• Journal of Gastric Cancer
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• v.7 no.1
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• pp.31-37
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• 2007

Purpose: A pancreas-preserving total gastrectomy (PPTG) was introduced to decrease the postoperative complications due to pancreatic resection. However, some complications, such as leakage of pancreatic juice, are still reported. Thus, the purpose of this study was to propose a supplementary procedure based on the results of treatment for gastric cancer at our hospital. Materials and Methods: From Jan. 1997 to Dec. 2004, the cases of 141 patients who underwent a PPTG for gastric cancer were reviewed retrospectively. The patients were divided into Group A (38 cases), patients who were treated using a conventional PPTG, and Group B (103 cases), patients who were treated using a new and improved PPTG. Their postoperative complications were compared. Results: No statistically significant differences in clinicopathologic data were noted between the two groups. The comparison of complications showed for groups A and B, respectively, 4 and 0 cases of pancreatic fistula, 1 and 0 cases of intraabdominal abscess, 2 and 0 cases of intraoperative pancreatic necrosis, and 2 and 2 cases of minor leakage. The difference in the prevalence of complications between the two groups was statistically significant (P=0.0001). Conclusion: In order to reduce the risk of PPTG-related complications, we used vascular clamps to observe the necrosis of the pancreatic tail before dividing the splenic artery, and this method resulted in a significant decrease in postoperative complications. Thus, we conclude that our use of vascular clamps in a PPTG is a simple and useful method for preventing postoperative complications.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.463-472
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• 1998

Biotechnology is the process of using biological system for the production of materials. Genetic engineering, a subset of biotechnology, is the process of altering biological systems by the purposeful manipulation of DNA It is a new field in biology and no topic in biology is more likely to impact our personal lives and is therefore more worthy of our attention and understanding. The purpose of this study was to investigate students' understanding of the concepts of biotechnology, and a test tool which is made up of 20 basic questions was developed for the study. The subject of this study was high school students and the sample size was 486. In order to find out the source of students' misunderstanding, we also analysed high school textbooks and teachers were given the same tool applied to students. Two-way ANOVA was used for the analysis. Major findings of this study are as following; 1. Mean score of students was 41, and there was a significant difference between the scores of boys and girls(p<0.05). Female students scored higher than male students. The variables "region" and "major" had no significant influence. 2. Students' the most misunderstood concepts were "monoclonal antibody" and "gene cloning". Many students thought that a plamid DNA originally has a useful DNA in it, which is apparently wrong. 3. Mean score of teachers was 82, and the variabes of gender and career did not have statistically significant influence on the result(p>0.05). 4. Teachers got the lowest scores on the concepts of "gene therapy", "the accomplishment of biotechnology in agriculture and medicine", and "plasmid DNA". The results of item analysis implied that teachers' misunderstanding might be a part of the sources of students' misunderstaning. 5. Out of 18 basic concepts selected in the study, only 10 concepts were explained well enough in most textbooks. The results of item analysis indicated that textbooks also could be a part of the source of students' misunderstanding.

• Journal of The Korean Association For Science Education
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• v.33 no.5
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• pp.1055-1086
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• 2013

The purpose of this study is to identify the formation and evolution patterns of a trading zone and to explore the difficulties teachers experience in the trading zone and their perceptions of the experience. Seven teachers involved in the 'STEAM Teacher Community' in a middle school located in the southern part of South Korea participated in this study. Participant observation and in-depth interviews were carried out, and reflective essays were collected for analysis. The results show that teachers successfully formed a trading zone to share their expertise when they developed teaching materials for the convergence of different subject matters. Moreover, such a trading zone evolved in the order of pre-trading zone, trading zone under elite control, trading zone with boundary object, and trading zone of shared mental model. The difficulties teachers experienced in the trading zone were categorized under the difference of culture and opinion across subject matters, the lack of motivation for convergence, the hegemony of convergence and far-fetched factors for convergence, and difficulty of communication due to jargons. Also teachers in this study experienced perceptual changes in the trading zone. The trading zone model drawn from the results of this study bring forth implications for voluntary teachers' learning community activity for the convergence of different subject matters.

• The Korean Journal of Air & Space Law and Policy
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• v.1
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• pp.223-243
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• 1989

The practical application of modern space science and technology have resulted in many actual and potential gains of mankind. These successes have conditioned and increased the need for a viable space law regime and the challenge of space has ultimately led to the formation of an international legal regime for space. Space law is no longer a primitive law. It is a modern law. Yet, in its stages of growth, it has not reached the condition of perfection. Therefore, under the existing state of thing, we could carefully say that the space law is one of the most newest fields of jurisprudence despite the fact that no one has so far defined it perfectly. However, if space law can be a true jurisprudential entity, it must be definable. In defining the space law, first of all, the grasp of it's nature iis inevitable. Although space law encompasses many tenets and facets of other legal discriplines, its principal nature is public international law, because space law affects and effects law relating intercourse among nations. Since early 1960s when mankind was first able to flight and stay in outer space, the necessity to control and administrate the space activities of human beings has growingly increased. The leading law-formulating agency to this purpose is the United Nation's ad hoc Committee on Peaceful Uses of Outer Space("COPUOS"). COPUOS gave direction to public international space law by establishing the 1963 Declaration of Legal Principles Governing the Activities of the States in the Exploration and Use of Outer Space("1963 Declaration"). The 1963 Declaration is very foundation of the five international multilateral treaties that were established successively after the 1963 Declaration. The five treaties are as follows: 1) The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space including Moon and other Celestial Bodies, 1967. 2) The Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space, 1968. 3) The Convention on International Liability for Damage Caused by Space Objects, 1972. 4) The Convention on Registration of Objects Launched into Outer Space, 1974. 5) The Agreement Governing Activities of States on the Moon and Other Celestial Bodies: Moon Treaty, 1979. The other face of space law is it's commercial aspect. Space is no longer the sole domination of governments. Many private enterprise have already moved directly or indirectly into space activities in the parts such as telecommunications and space manufacturing. Since space law as the public international law has already advanced in accordance with the developments of space science and technology, there left only a few areas untouched in this field of law. Therefore the possibility of rapid growth of space law is expected in the parts of commerical space law, as it is, at this time, in a nascent state. The resources of the space environment are also commercially both valuable and important since the resources include the tangible natural resources to be found on the moon and other celestial bodies. Other space-based resources are solar energy, geostationary and geosynchronous orbital positions, radio frequencies, area possibly suited to human habitations, all areas and materials lending themselves to scientific research and inquiry. Remote sensing, space manufacturing and space transportation services are also another potential areas in which commercial. endeavors of Mankind can be carried out. In this regard, space insurance is also one of the most important devices allowing mankind to proceed with commercial space venture. Thus, knowlege of how space insurance came into existence and what it covers is necessary to understand the legal issues peculiar to space law. As a conclusion the writer emphasized the international cooperation of all nations in space activities of mankind, because space commerce, by its nature, will give rise many legal issues of international scope and concern. Important national and world-community interests would be served over time through the acceptance of new international agreements relating to remote sencing, direct television broadcasting, the use of nuclear power sources in space, the regularization of the activities of space transportation systems. standards respecting contamination and pollution, and a practical boundary between outer space and air space. If space activity regulation does not move beyond the national level, the peaceful exploration of space for all mankind will not be realized. For the efficient regulation on private and governmental space activities, the creation of an international space agency, similar to the International Civil Aviation Organization but modified to meet the needs of space technology, will be required. But prior to creation of an international organization, it will be necessary to establish, at national level, the Office of Air and Space Bureau, which will administrate liscence liscence application process, safety review and sale of launch equipment, and will carry out launch service.

• Korean Journal of Oriental Medicine
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• v.11 no.1
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• pp.83-95
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• 2005

Arriving in the '90s, the worldwide trend of longing for naturalism and popularity of complementary and alternative medicine in America has caused traditional Oriental Medicine and medicinal plants markets to develop rapidly. And China has been pursuing the globalization policy of Chinese medicine by the initiation of the society of traditional Chinese medicine. Under this situation, it is a time for us to think about in a serious manner whether existing organization and system of Oriental medicine and the department of Oriental medicine at the schools in Korea reflects reality or whether we should turn it to some different direction. The purpose of this research is to compare the educational systems in relation to the traditional medicine between Korea and China, and to seek and look into its implication, and also to make a contribution to further developments and changes of direction for Oriental medicine education in Korea. 1. I investigated carefully the educational system of the colleges of traditional Chinese medicine, and results from this survey revealed that the academic institutions for the medicinal training in China consists of varied systems, such as 7-year program for medicinal training linking with master degree course, 6-year program, 5-year program (more than 90%), 4-year program, and so on, so then China has been raising the specialists in their traditional medicine arena through those varied academic programs. Such an educational system as the department of Chinese medicine in order to educate and produce specialists or pharmacists specializing in traditional Chinese medicine is operated only by Beijing University of Chinese Medicine in terms of 7-year academic program for medicinal major that linked with master degree course, and the rest of schools run 5-year program or 4-year program (more than 90%). And other human resources required for cultivation of medicinal plants and manufacturing herbal medicines are mostly trained at 3-year course colleges or 2-year course vocational schools. 2. In connection with traditional Chinese medicine, there are a variety of departments in the schools in China other than Chinese Medicine and Pharmacology: i.e. Acupuncture, Moxibustion and Tuina, Preclinical Medicine, Pharmaceuticals, Materials of Medicine, Phrenology and Law, Languages and Literature, etc. Therefore, these programs constitute multi academic system and also an appropriate educational base that fits in varied needs of market. Particularly, the university having 7-year program emphasize, English proficiency so that it can be considered that this academic program is a specialized course in order to achieve globalization of Chinese medicine. 3. In Korea, there are only 11 Oriental medicine schools with 6-year program which have been established by the private foundations and 3 departments of Oriental medicine at 4-year university. Therefore, we need to establish varied departments related to branches of our traditional medicine like China. 4. It is necessary to establish varied new departments related to Oriental Medicine that will be able to take a professional role in the course of pursuing the strategic goals such as scientification, globalization, standardization of Oriental Medicine, also that will meet needs of the world alternative and complementary medicine and herbal medicine markets. In order to achieve such strategic goals, we need to organize an academic system that will be different from existing systems and programs, also we are required to research further on the educational and training programs.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.57-66
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• 2007

Natural gases generally consist of mainly $^{12}C$ and about 1.1% of $^{13}C$. It is well known that a stable carbon isotope, $^{13}C$, has been widely used for the applications of medical, pharmaceutical, and agricultural tracers. As a result, the development of the separation and concentrating technology of $^{13}C$ can cause of high value-added products and the possibility of the generation of new carbon materials, In general, there are two kinds of approaches to obtain a stable $^{13}C$ isotope by the separation of cryogenic distillation. One is to obtain a concentrated $^{13}CH_4$ isotope from natural gas. Another approach is to get concentrated $^{13}CO$ by distillation followed by a chemical reaction of $CH_4$ and $H_2O$. In this study, rigorous process simulations of the cryogenic distillation have been performed and analyzed for the concentrated separation of $^{13}C$ isotopes from LNG and NG by using commercial process simulator. Due to the very small differences of relative volatilities and separabilities of $^{12}C$ and $^{13}C$, the process design and operation of effective separation and concentration of $^{13}C$ need special strategies and feasibility studies. Utilization of vapor pressure data to acentric factor in SRK equation of state and optimized process conditions have been able to predict for the effective of the separation yield and concentration of $^{13}C$ for the cryogenic distillation. The various operation strategies for both batch and continuous cryogenic distillation are also studied and suggested for the basic design of the process. Development of this study can provide a tool for the effective design and operation of the cryogenic separation of $^{13}C$.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.116-123
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• 2003

Purpose : The present study was undertaken to evaluate the usefulness of cerebral diffusion (DWI) and perfusion MR imaging (PWI) in rabbit models with hyperacute cerebral ischemic infarction. Materials and Methods : Experimental cerebral infarction were induced by direct injection of mixture of Histoacryl glue, lipiodol, and tungsten powder into the internal cerebral artery of 6 New-Zealand white rabbits, and they underwent conventional T1 and T2 weighted MR imaging, DWI, and PWI within 1 hour after the occlusion of internal cerebral artery. The PWI scan for each rabbit was obtained at the level of lateral ventricle and 1cm cranial to the basal ganglia. By postprocessing using special imaging software, perfusion images including cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps were obtained. The detection of infarcted lesion were evaluated on both perfusion maps and DWI. MTT difference time were measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Results : In all rabbits, there was no abnormal signal intensity on T2WI. But on DWI, abnormal high signal intensity, suggesting cerebral infarction, were detected in all rabbits. PWI (rCBV, CBF and MTT map) also showed perfusion defect in all rabbits. In four rabbits, the calculated square of perfusion defect in MTT map is larger than that of CBF map and in two rabbits, the calculated size of perfusion defect in MTT map and CBF map is same. Any rabbits do not show larger perfusion defect on CBF map than MTT map. In comparison between CBF map and DWI, 3 rabbits show larger square of lesion on CBF map than on DWI. The others shows same square of lesion on both technique. The size of lesion shown in 6 MTT map were larger than DWI. In three cases, the size of lesion shown in CBF map is equal to DWI. But these were smaller than MTT map. The calculated square of lesion in CBF map, equal to that of DWI and smaller than MTT map was three. And in one case, the calculated square of perfusion defect in MTT map was largest, and that of DWI was smallest. Conclusion : DWI and PWI may be useful in diagnosing hyperacute cerebral ischemic infarction and in e-valuating the cerebral hemodynamics in the rabbits.