• KDI Journal of Economic Policy
• /
• v.12 no.1
• /
• pp.31-68
• /
• 1990

The concentration of economic power takes the form of one or a few firms controlling a substantial portion of the economic resources and means in a certain economic area. At the same time, to the extent that these firms are owned by a few individuals, resource allocation can be manipulated by them rather than by the impersonal market mechanism. This will impair allocative efficiency, run counter to a decentralized market system and hamper the equitable distribution of wealth. Viewed from the historical evolution of Western capitalism in general, the concentration of economic power is a paradox in that it is a product of the free market system itself. The economic principle of natural discrimination works so that a few big firms preempt scarce resources and market opportunities. Prominent historical examples include trusts in America, Konzern in Germany and Zaibatsu in Japan in the early twentieth century. In other words, the concentration of economic power is the outcome as well as the antithesis of free competition. As long as judgment of the economic system at large depends upon the value systems of individuals, therefore, the issue of how to evaluate the concentration of economic power will inevitably be tinged with ideology. We have witnessed several different approaches to this problem such as communism, fascism and revised capitalism, and the last one seems to be the only surviving alternative. The concentration of economic power in Korea can be summarily represented by the "jaebol," namely, the conglomerate business group, the majority of whose member firms are monopolistic or oligopolistic in their respective markets and are owned by particular individuals. The jaebol has many dimensions in its size, but to sketch its magnitude, the share of the jaebol in the manufacturing sector reached 37.3% in shipment and 17.6% in employment as of 1989. The concentration of economic power can be ascribed to a number of causes. In the early stages of economic development, when the market system is immature, entrepreneurship must fill the gap inherent in the market in addition to performing its customary managerial function. Entrepreneurship of this sort is a scarce resource and becomes even more valuable as the target rate of economic growth gets higher. Entrepreneurship can neither be readily obtained in the market nor exhausted despite repeated use. Because of these peculiarities, economic power is bound to be concentrated in the hands of a few entrepreneurs and their business groups. It goes without saying, however, that the issue of whether the full exercise of money-making entrepreneurship is compatible with social mores is a different matter entirely. The rapidity of the concentration of economic power can also be traced to the diversification of business groups. The transplantation of advanced technology oriented toward mass production tends to saturate the small domestic market quite early and allows a firm to expand into new markets by making use of excess capacity and of monopoly profits. One of the reasons why the jaebol issue has become so acute in Korea lies in the nature of the government-business relationship. The Korean government has set economic development as its foremost national goal and, since then, has intervened profoundly in the private sector. Since most strategic industries promoted by the government required a huge capacity in technology, capital and manpower, big firms were favored over smaller firms, and the benefits of industrial policy naturally accrued to large business groups. The concentration of economic power which occured along the way was, therefore, not necessarily a product of the market system. At the same time, the concentration of ownership in business groups has been left largely intact as they have customarily met capital requirements by means of debt. The real advantage enjoyed by large business groups lies in synergy due to multiplant and multiproduct production. Even these effects, however, cannot always be considered socially optimal, as they offer disadvantages to other independent firms-for example, by foreclosing their markets. Moreover their fictitious or artificial advantages only aggravate the popular perception that most business groups have accumulated their wealth at the expense of the general public and under the behest of the government. Since Korea stands now at the threshold of establishing a full-fledged market economy along with political democracy, the phenomenon called the concentration of economic power must be correctly understood and the roles of business groups must be accordingly redefined. In doing so, we would do better to take a closer look at Japan which has experienced a demise of family-controlled Zaibatsu and a success with business groups(Kigyoshudan) whose ownership is dispersed among many firms and ultimately among the general public. The Japanese case cannot be an ideal model, but at least it gives us a good point of departure in that the issue of ownership is at the heart of the matter. In setting the basic direction of public policy aimed at controlling the concentration of economic power, one must harmonize efficiency and equity. Firm size in itself is not a problem, if it is dictated by efficiency considerations and if the firm behaves competitively in the market. As long as entrepreneurship is required for continuous economic growth and there is a discrepancy in entrepreneurial capacity among individuals, a concentration of economic power is bound to take place to some degree. Hence, the most effective way of reducing the inefficiency of business groups may be to impose competitive pressure on their activities. Concurrently, unless the concentration of ownership in business groups is scaled down, the seed of social discontent will still remain. Nevertheless, the dispersion of ownership requires a number of preconditions and, consequently, we must make consistent, long-term efforts on many fronts. We can suggest a long list of policy measures specifically designed to control the concentration of economic power. Whatever the policy may be, however, its intended effects will not be fully realized unless business groups abide by the moral code expected of socially responsible entrepreneurs. This is especially true, since the root of the problem of the excessive concentration of economic power lies outside the issue of efficiency, in problems concerning distribution, equity, and social justice.

• Journal of Intelligence and Information Systems
• /
• v.24 no.2
• /
• pp.149-169
• /
• 2018

Korea is currently accumulating a large amount of data in public institutions based on the public data open policy and the "Government 3.0". Especially, a lot of data is accumulated in the tourism field. However, the academic discussions utilizing the tourism data are still limited. Moreover, the openness of the data of restaurants, hotels, and online tourism information, and how to use SNS Big Data in tourism are still limited. Therefore, utilization through tourism big data analysis is still low. In this paper, we tried to analyze influencing factors on foreign tourists' satisfaction in Korea through numerical data using data mining technique and R programming technique. In this study, we tried to find ways to revitalize the tourism industry by analyzing about 36,000 big data of the "Survey on the actual situation of foreign tourists from 2013 to 2015" surveyed by the Korea Culture & Tourism Research Institute. To do this, we analyzed the factors that have high influence on the 'Satisfaction', 'Revisit intention', and 'Recommendation' variables of foreign tourists. Furthermore, we analyzed the practical influences of the variables that are mentioned above. As a procedure of this study, we first integrated survey data of foreign tourists conducted by Korea Culture & Tourism Research Institute, which is stored in the tourist information system from 2013 to 2015, and eliminate unnecessary variables that are inconsistent with the research purpose among the integrated data. Some variables were modified to improve the accuracy of the analysis. And we analyzed the factors affecting the dependent variables by using data-mining methods: decision tree(C5.0, CART, CHAID, QUEST), artificial neural network, and logistic regression analysis of SPSS IBM Modeler 16.0. The seven variables that have the greatest effect on each dependent variable were derived. As a result of data analysis, it was found that seven major variables influencing 'overall satisfaction' were sightseeing spot attraction, food satisfaction, accommodation satisfaction, traffic satisfaction, guide service satisfaction, number of visiting places, and country. Variables that had a great influence appeared food satisfaction and sightseeing spot attraction. The seven variables that had the greatest influence on 'revisit intention' were the country, travel motivation, activity, food satisfaction, best activity, guide service satisfaction and sightseeing spot attraction. The most influential variables were food satisfaction and travel motivation for Korean style. Lastly, the seven variables that have the greatest influence on the 'recommendation intention' were the country, sightseeing spot attraction, number of visiting places, food satisfaction, activity, tour guide service satisfaction and cost. And then the variables that had the greatest influence were the country, sightseeing spot attraction, and food satisfaction. In addition, in order to grasp the influence of each independent variables more deeply, we used R programming to identify the influence of independent variables. As a result, it was found that the food satisfaction and sightseeing spot attraction were higher than other variables in overall satisfaction and had a greater effect than other influential variables. Revisit intention had a higher ${\beta}$ value in the travel motive as the purpose of Korean Wave than other variables. It will be necessary to have a policy that will lead to a substantial revisit of tourists by enhancing tourist attractions for the purpose of Korean Wave. Lastly, the recommendation had the same result of satisfaction as the sightseeing spot attraction and food satisfaction have higher ${\beta}$ value than other variables. From this analysis, we found that 'food satisfaction' and 'sightseeing spot attraction' variables were the common factors to influence three dependent variables that are mentioned above('Overall satisfaction', 'Revisit intention' and 'Recommendation'), and that those factors affected the satisfaction of travel in Korea significantly. The purpose of this study is to examine how to activate foreign tourists in Korea through big data analysis. It is expected to be used as basic data for analyzing tourism data and establishing effective tourism policy. It is expected to be used as a material to establish an activation plan that can contribute to tourism development in Korea in the future.

• Journal of Intelligence and Information Systems
• /
• v.24 no.2
• /
• pp.59-83
• /
• 2018

With the increasing importance of sentiment analysis to grasp the needs of customers and the public, various types of deep learning models have been actively applied to English texts. In the sentiment analysis of English texts by deep learning, natural language sentences included in training and test datasets are usually converted into sequences of word vectors before being entered into the deep learning models. In this case, word vectors generally refer to vector representations of words obtained through splitting a sentence by space characters. There are several ways to derive word vectors, one of which is Word2Vec used for producing the 300 dimensional Google word vectors from about 100 billion words of Google News data. They have been widely used in the studies of sentiment analysis of reviews from various fields such as restaurants, movies, laptops, cameras, etc. Unlike English, morpheme plays an essential role in sentiment analysis and sentence structure analysis in Korean, which is a typical agglutinative language with developed postpositions and endings. A morpheme can be defined as the smallest meaningful unit of a language, and a word consists of one or more morphemes. For example, for a word '예쁘고', the morphemes are '예쁘(= adjective)' and '고(=connective ending)'. Reflecting the significance of Korean morphemes, it seems reasonable to adopt the morphemes as a basic unit in Korean sentiment analysis. Therefore, in this study, we use 'morpheme vector' as an input to a deep learning model rather than 'word vector' which is mainly used in English text. The morpheme vector refers to a vector representation for the morpheme and can be derived by applying an existent word vector derivation mechanism to the sentences divided into constituent morphemes. By the way, here come some questions as follows. What is the desirable range of POS(Part-Of-Speech) tags when deriving morpheme vectors for improving the classification accuracy of a deep learning model? Is it proper to apply a typical word vector model which primarily relies on the form of words to Korean with a high homonym ratio? Will the text preprocessing such as correcting spelling or spacing errors affect the classification accuracy, especially when drawing morpheme vectors from Korean product reviews with a lot of grammatical mistakes and variations? We seek to find empirical answers to these fundamental issues, which may be encountered first when applying various deep learning models to Korean texts. As a starting point, we summarized these issues as three central research questions as follows. First, which is better effective, to use morpheme vectors from grammatically correct texts of other domain than the analysis target, or to use morpheme vectors from considerably ungrammatical texts of the same domain, as the initial input of a deep learning model? Second, what is an appropriate morpheme vector derivation method for Korean regarding the range of POS tags, homonym, text preprocessing, minimum frequency? Third, can we get a satisfactory level of classification accuracy when applying deep learning to Korean sentiment analysis? As an approach to these research questions, we generate various types of morpheme vectors reflecting the research questions and then compare the classification accuracy through a non-static CNN(Convolutional Neural Network) model taking in the morpheme vectors. As for training and test datasets, Naver Shopping's 17,260 cosmetics product reviews are used. To derive morpheme vectors, we use data from the same domain as the target one and data from other domain; Naver shopping's about 2 million cosmetics product reviews and 520,000 Naver News data arguably corresponding to Google's News data. The six primary sets of morpheme vectors constructed in this study differ in terms of the following three criteria. First, they come from two types of data source; Naver news of high grammatical correctness and Naver shopping's cosmetics product reviews of low grammatical correctness. Second, they are distinguished in the degree of data preprocessing, namely, only splitting sentences or up to additional spelling and spacing corrections after sentence separation. Third, they vary concerning the form of input fed into a word vector model; whether the morphemes themselves are entered into a word vector model or with their POS tags attached. The morpheme vectors further vary depending on the consideration range of POS tags, the minimum frequency of morphemes included, and the random initialization range. All morpheme vectors are derived through CBOW(Continuous Bag-Of-Words) model with the context window 5 and the vector dimension 300. It seems that utilizing the same domain text even with a lower degree of grammatical correctness, performing spelling and spacing corrections as well as sentence splitting, and incorporating morphemes of any POS tags including incomprehensible category lead to the better classification accuracy. The POS tag attachment, which is devised for the high proportion of homonyms in Korean, and the minimum frequency standard for the morpheme to be included seem not to have any definite influence on the classification accuracy.

• Journal of agricultural medicine and community health
• /
• v.27 no.2
• /
• pp.87-105
• /
• 2002

In order to find out the knowledge, attitude, and experience of community health practitioners(CHP) on complementary therapy, 393 community health practitioners who provide primary health care service in Busan, Kyeongnam, and Daegu, Gyeongbuk regions were interviewed or surveyed by mail from February 1st to March 31st, 2002. In terms of interest of CHPs toward 11 different hinds of complementary therapy, the rate of interest for soojichim was the highest with 75.3%. Aroma therapy had the interest of 71.0% of the CHPs, oriental medicine had 67.4%, and massage had 67.4%. The interest for shiatsu was 64.6%, while homeopath had the lowest rate of interest of 18.1%. In terms of reliance on the treatment results, oriental medicine scored the highest with 92.6%, and soojichim, massage, and shiatsu followed with 85.5%, 83.7%, and 81.7% respectively. Homeopath had the lowest reliance of 18.1%. The 65.1% of the CHPs had the experience of recommending oriental medicine to patients. 50.4% indicated that they had recommended soojichim, and 44.8% had recommended massage before. Shiatsu and aromatherapy followed with 34.4% and Homeopath had the lowest rate of 2.80%. When CHPs were asked if they had received any training in complementary therapy, 33.1% indicated that they had studied soojichim and 13.2%stated that they had learned oriental medicine. Aromatherapy, massage, and shiatsu followed with 11.2%, 8.4%, and 5.6% respectively On the other hand, none of the CHPs had received training in homeopath. In terms of using complementary therapy during the past 5 years, 23.9% had been treated with oriental medicine, and 18.896 had received soojichim. 5.9% had received aromatherapy, 5.3% had used massage, and 5.1% had experience with shiatsu. None of the practitioners had used homeopath during the past 5 years. Significantly many number of practitioners indicated that they had excellent treatment results with all hinds of complementary therapy, and there were rare cares of side effects. When they were asked if they wanted complementary therapy to become part of the curriculum during re-training or training for public service personnels, 78100 wanted soojichim, 69.2% wanted oriental medicine, and 67.9% wanted aroma therapy. 63.9% wanted shiatsu to be included, and 63.1% wanted massage. When CHPs were asked if they wanted to use complementary therapy during primary health care, 63.6% wanted to use soojichim, 52.9% wanted massage, and 51.9% wanted to use aroma therapy. Oriental medicine also showed a high rate of 50.1%. On the other hand, only a small percentage wanted to use chiropractic or homeopath with 17.0% and 12,2% respectively. Among the CHPs, there were some who had administered complementary therapy during the past 5 years. 84% had administered soojichim, 4.6% had administered oriental medicine, and 2.5% had administered massage 2.5% of the CHPs answered that they had administered aromatherapy. However, none of them had administered apitherapy or homeopath. Most of patients showed positive responses, and the rate of side effect was very low. As shown in the above results, although CHPs have a high rate of interest, reliance, and experience in recommending complementary therapy, only a low percentage of them had received any training in complementary therapy. In addition, since there were little side effects when they received or administered complementary therapy, they hoped complementary therapy, which can be beneficial to health, to be introduced to the curriculum. Therefore, in order to provide community members with complementary therapy and the correct information regarding the selection of complementary therapy that could be beneficial to health, a policy of continuous interest and support is needed so that CHPs can he provided with a systemic and rational curriculum of complementary therapy.

• Journal of agricultural medicine and community health
• /
• v.27 no.2
• /
• pp.75-86
• /
• 2002

This study was conducted to investigate the changes in patients and medical services before and after the Separation of Prescription and Dispensing in Health Center. For the purpose of this study, prescription data of 5,890 prescribed patients in March 2000(before the Separation of Prescription and Dispensing) and 3,496 prescribed patients in March 2001(after the Separation) in 4 Health Centers located in Gyeongsangbuk-do and Gyeongsangnam-do were collected. For investigation of the change of character of prescribed patients and the disease, sex, age, chief diagnosis, the hind of medical insurance, days of visit, days of prescription were investigated by using National Health Insurance claim data. And for investigation of change of prescription, prescribed drugs per each claim, the use rate of antibiotics, injection, and high-price antiphlogistic drug were investigated for acute respiratory disease and musculoskeletal disease. The major results were as follows: For the changes of prescribed patients of each disease, patients with acute respiratory disease were decreased by 49.7% after the Separation of Prescription and Dispensing than before the Separation of Prescription and Dispensing and patients with hypertension(18.1%), patients with musculoskeletal disease(70.5%), patients with diabetes(8.5%), patients with digestive organ disease(71.2%), patients with chronic respiratory disease(76.4%) were decreased. But patients with urethritis were increased by 66.7%. The mean Health Center visited days of prescribed patients decreased significantly after the Separation of Prescription and Dispensing than before in both male and female(p<0.01) and in health insurance patients(p<0.01). For the each of the disease, hypertension, diabetes, musculoskeletal disease decreased. The mean prescribed days increased after the Separation of Prescription and Dispensing than before(p<0.01). According to the kine of disease, the mean prescribed days increased after the Separation of Prescription and Dispensing than before in all the diseases except the urethritis(p<0.01). For acute respiratory diseases, number of prescribed drugs per each claim decreased significantly after the Separation of Prescription and Dispensing(4.7 drugs) than before(4.9 drugs) and the prescription rate of injection decreased significantly from 63.8% to 7.70%, and the prescription rate of antibiotics decreased significantly from 337% to 19.1%(p<0.01). For musculoskeletal diseases before and after Separation of Prescription and Dispensing, number of prescribed drugs per each claim decreased significantly from 3.7 to 3.2 and the prescription rate of injection decreased significantly from 64.9% to 1.7%, and the prescription rate of high-price antiphlogistic drugs increased significantly from 29.1% to 397%(p<0.01). In consideration of above findings, the mean visited days decreased and on the contrary, the mean prescribed days per each prescription increased after Separation of Prescription and Dispensing than before in health centers. For the prescription pattern of physicians, number of prescribed drugs and the prescription rates of injection and antibiotics per each claim decreased, but the prescription rate of high-price antiphlogistic drugs increased after Separation of Prescription and Dispensing.

• Journal of agricultural medicine and community health
• /
• v.24 no.1
• /
• pp.79-89
• /
• 1999

The purpose of this study is to compare health status and activities for the pain and no-pain groups in the elderly. The study subjects included 189 elderly people(65 years and older) living in an urban area. They were surveyed at their homes through interview using a closed-ended questionnaire from Nov. 6th. to Nov. 16th. 1997. The instrument used in the study was selected after carefully reviewing pain-related articles and records well described the characteristics of the elderly. The data were analysed by using descriptive statistics and chi-square tests. The findings were as follows : Of the 189 subjects, 83.6% reported experiencing the pain for the last year. By the age, there were significant differences between the pain and no-pain group(${\chi}^2$=9.572, p=.023). The percentage of the pain complainers was the highest in 80 years and older(100.0%), followed by 70~74(89.1%), 75~79(81.3%), 65~69(76.8%) which presented crude increase according to age. By sex, men had lower pain prevalence(69.5%) than that of women(90.0%). The number of pain complainers was higher in women than men(${\chi}^2$=12.448, p=.023). There were significant differences between the pain and no-pain groups by spouse distribution(${\chi}^2$=10.736, p=.001), educational state(${\chi}^2$=13.020, p=.000), occupation(${\chi}^2$=18.807, p=.000). Pain prevalence in the subjects having no spouse(59.3%) was higher than those having spouse(40.7%), Illiteracy rate was higher in pain group(49.0%) than no-pain group(13.3%). The number of the subjects having occupation(full time or part time) was fewer in pain group than no-pain group. By health status, there were significant differences between two groups(${\chi}^2$=40.055, p=.000). : the pain group showed poor(61.4%), followed by moderate(22.1%), good(16.5%) while no-pain group showed good(64.5%), moderate(29.0%), poor(6.5%). By activities, there were significant differences between the pain and no-pain groups. The pain group was disturbed more severely than the no-pain group in movement(${\chi}^2$=57.829, p=.000), sleep(${\chi}^2$=12.785, p=.000), usual activities(${\chi}^2$=39.196, p=.000), receiving guests(${\chi}^2$=13.163, p=.000), and hobbies and recreation(${\chi}^2$=28.177, p=.000).

• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.4
• /
• pp.343-358
• /
• 2011

As implant treatment has become popular, lots of different shapes and materials of the implant upper component have been supplied. And there are also diverse reports about failures including loosening of the abutment screw which is one of the most common reason. Purpose : The purpose of this study is to find out how different screw tightening orders and methods influence on screw loosening according to the different connection systems. The upper component was fabricated by casting method. After fabricating master models that are precisely attached to the upper component, 5 experimental models each for the external connection system and internal connection system were fabricated using splinting impression technique. First, to find out the influence of the screw tightening order, screws were tightened in 3 orders; 1-2-3-4, 2-3-1-4, 2-4-3-1. After tightening, removal torque values (RTV) of each group was measured. And also to find out the influence of screw tightening method, a model with 2-3-1-4 screw tightening order was tightened with 30 Ncm at one time(1-step method) and the RTV was compared with the same order group (2-3-1-4) in the 2 step method. In the external connection system, RTV appeared significantly lower in group 2-3-1-4 than group 2-4-3-1 (p<0.05). And also in the internal connection system, the RTV of group 2-3-1-4 appeared significantly lower than that of group 2-4-3-1 and 1-2-3-4 (p<0.05). When comparing the tightening number of the screw without considering the screw tightening order, the first tightened screw appeared significantly higher RTV than the second one in the external connection system (p<0.05), however there was no significant difference from the first tightened screw to the last tightened screw in the internal connection system. And there was no statistically significant difference between the two screw tightening methods in both internal and external connection system. In the comparison of external and internal connection system, each RTV appeared 16.27 Ncm and 14.25 Ncm and appeared as a statistically significant difference (p<0.05). There was a significant difference in RTV measured according to the screw tightening order. The lowest RTV appeared in the groups started tightening from the middle. There was also a significant difference in RTV between the two connection system groups. A further study is needed to find out the influence factors in RTV and also a study is required related to the load condition.

• Korean journal of applied entomology
• /
• v.9 no.2
• /
• pp.57-74
• /
• 1970

These experiments were conducted to investigate the :actors influencing the systemic action of Dimethoate (O,O-dimethyl-S-(N-methylcarhamoylmethyl) photphorodithioate) to rice seeds and the phytotoxic effects on the seed germination. Dimethoate $(Roxion^{(R)})$ $40\%$ emulsion was used. The varieties tested were Jinheung. Nongkwang,Suwon #82, Norm #6, Paltal, Shirogane, Suseong, Pungkwang, Shin #2, Fujisaka #5, Kwanok, and Jaekeun. The permeated Dimethoate was extracted from the treated seeds by chloroform and quantities were determined by Spectrophotometer. The phytotoxicity was evaluated from the effects on the germination of the treated seeds which were kept in an incubator. The oxygen consumption was measured by Warburg Manometer at $30^{\circ}C$ for 60 minutes. Indices of KOH disintegration of seeds and chemical composition of the seeds were also determined. The results obtained were as followings; 1) The amount of permeated Dimethoate in the seeds showed remarkable differences with varieties. The amount of Dimethoate per 100 grains was greater as in the ascending order of Suseong, Kwanok, Nongkwang, Jinheung, Paltal, Fujisaka #5, Suwon #82, Norm #6, Shirogane, Shin #2, Pungkwang and Jaekeun. 2) It was observed that the total amount of Dimethoate in the seeds(mg./100 grains) were greater among the varieties with large grain than those with small grains, while reverse cases were true in the amount of Dimethoate in a gramme of seeds, probably because of the greater surface areas In a small grains for a gramme weight. 3) There was no significant correlation between the permeated amount of Dimethoate and amount of absorbed water by the seeds when the seeds were treated with $0.1\%$ Dimethoate for 24 and 48 hours. 4) The permeability of Dimethoate to seeds significantly increased in the prolonged soaking periods, higher concentration, and higher temperature. 5) When the seeds were treated with $0.1\%$ Dimethoate for 24 and 48 hours at $15^{\circ},\;20^{\circ},\; 20^{\circ},\; and \;30^{\circ}C$, the permeated amount of Dimethoate were increased at higher temperature. It seems to be that the more active penetration of Dimethoate was involved at the higher temperature. 6) The phytotoxic effects of Dinethoate on the seed germination varied with the varieties. An descending order of varietal tolerance of seeds was as followings: Jinheung, Fujisaka #5, Suwon #82, Paltal, Nongkwang, Jaekeun, Shin #2, Kwanok, Shirogane, Pungkwang, Suseong, and Norm #6. 7) There was a positive correlation between the amount of Dimethoate permeated into the seeds (mg./gram. of seeds) and phytotoxicity of seeds. 8) The Phytotoxic effects of Dimethoate showed close correlation with the degree of KOH disintegration of seeds, average germination periods, and oxygen respiration of seeds. 9) It was observed that higher protein contents of the seeds decreased the phytotoxic effects of Dimethoate. 10) Relatively high negative correlation between the degree of KOH disintegration of seeds and crude protein content of the seeds was observed. 11) The average germination period was delayed for about 2 days when the seeds were treated with $0.2\%$ Dimethoate for 24 hours at $30^{\circ}C$. 12) The oxygen consumption of the seeds treated with $0.2\%$ Dimethoate for 24 hours at $30^{\circ}C$ was greatly decreased when compared with that of the normal seeds. 13) The amount of oxygen consumption of the seeds (in 24 hours after 24 hours water soaking) was negatively correlated with the average germination periods of the seeds.

• Journal of Oral Medicine and Pain
• /
• v.33 no.3
• /
• pp.279-294
• /
• 2008

This study aimed to make an analysis of the occlusion in the state of muscle fatigue produced by excessive mouth opening and clenching during the dental treatment to control the dental pain and to evaluate the sensory nerve in the muscle pain state. Most of the reasons why patients visit the dental office result in pain-either conceivably the dental origin pain or the non-dental origin pain. The dental offices have many therapeutic actions to produce the masticatory muscle fatigue for the treatment. Dental treatment with long minutes of mouth opening can cause some headaches, masticatory muscle pain and mouth opening difficulties. Patients with mastication problems who visits a dental office to alleviate pain run against another unexpected pain with other aspects. This study uses T-scan II system(Tekscan Co., USA) for the evaluation on the occlusal pattern in the experimental muscle fatigue after clenching, opening the mouth excessively and chewing gum. The occlusal contact pattern is analyzed by the contact timing, namely first, intercuspal, maximum and end point of contact. This inspection was performed at frequencies of 2000Hz, 250 Hz and 5 Hz before and after each experimental muscle pain was produced to 24 subjects who had normal occlusion without the orthodontic treatment or a wide range of the prosthesis by using $neurometer^{\circledR}$ CPT/C(Neurotron, Inc. Baltimore, Maryland, USA). The measuring sites were mandibular nerve experimental muscle fatigue respectively. This study could obtain the following results after the assessment of occlusion and sensory nerve of the experimental muscle fatigue. 1. There were the fastest expression after the excessive mouth opening in muscle fatigue and after tooth clenching in muscle pain. In the visual analog scale that records the subjective level, there was the highest scale after the clenching in the muscle fatigue in jumping off the point of pain. 2. Tooth contact time, contact force, relative contact force on the point of the first contact had no difference, and there were decreases in the contact force after the excessive mouth opening on intercuspal position point, after the excessive mouth opening and the gum chewing on the point of the maximum, and in the contact time after all the experimental muscle fatigue state on the point of the end contact. 3. There was no statistic significance in the current perception threshold before and after the experimental muscle fatigue. 4. There was no significant difference in the contact number, the maximal contact number on the point of the first contact, and the contact number after the mouth opening and gum chewing on the point of the intercuspal position and the contact number after the experimental muscle fatigue on the maximum point, and showed significant decreases. In conclusion, it was found that the occlusal pattern can cause the changes on the case of the clinical muscle weakness by intra-external oral events. It was important that the sedulous attention to details is required during dental treatment in case of excessive mouth opening, mastication and clenching.

• Journal of Periodontal and Implant Science
• /
• v.24 no.3
• /
• pp.581-596
• /
• 1994

This in vitro study was undertaken to obtain optimal tetracycline concentration that aids proliferation and spreading of human periodontal ligament cells, for clinical application in root surfaces of periodontally diseased teeth. Periodontal ligament cells used in this study were obtained from explants of periodontal ligament of 1st premolar teeth which were extracted for the purpose of orthodontic treatment. The cells were cultured in Dulbecco's Modified Eagle Medium(DMEM) supplemented with 100 U/ml penicillin, $100\;{\mu}g/ml$ streptomycin and 10% FBS at $37^{\circ}C$, 100% humidity, 5% $CO_2-95%$ air. Cells were used between the third to 4th passage. After root planing of periodontally extracted teeth, the root slabs were cut with carborundum disk. In the cell proliferation experiment, experimental groups were root planing only group, immersed groups in 25, 50, 75, 100, 150mg/ml aqueous solution of Tetracycline HCl followed by a vigorous rinse in PBS. Human PDL cells at concentration of $1{\times}10^5\;cells/ml$ were seeded in each culture well which contained root slabs and incubated for 6 hours. Then, all of the root slabs were moved into new 24 culture well and incubated 24, 48 and 72 hours. The cell counting was done by inverted phase contrast microscope after trypsinization. The following results were obtained. The cell number was increased in order root planing only group, 25, 150, 50, 75, 100mg/ml of Tetracycline HCl treated group in 24, 48 and 72 hours. The maximal cell number was obtained when the root slabs were immersed in solution with 100mg/ml of Tetracycline HCl. There were statistically significant between the root planing only group and 75, 100 mg/ml of Tetracycline HCl treated group in 24 hours, between the root planing only group and 100mg/ml of Tetracycline HCl treated group in 48 hours, between the root planing only group and 50, 75, 100mg/ml of Tetracycline HCl treated group, between 25 and 100mg/ml of Tetracycline HCl treated group in 72 hours(p<0.05). In the cell spreading experiment, after 30 minutes of incubated, in the root planing only group, the cells were generally round in shape. The cell surface was mostly covered with blebs. The cells started to attach to root surface by cytoplasmic extension in 50, 100mg/ml of Tetracycline HCl treated groups, more numerous cells attached to root surface than root planing only group. Many orifices of dentinal tubule were exposed, cells showed radially spreaded cytoplasm and unspreaded central region of the cell was covered with blebs. After 6 hours of incubation, in the root planing only group, cells showed radially spreaded cytoplasm and were attached flat appearance. In 50, 100mg/ml of Tetracycline HCl treated groups, cellular margin was concaved and cytoplasm showed elongated appearance with polarity. After 24 hours of incubation, in the root planing group, cells showed characteristic polarity. In 50, 100mg/ml of Tetracycline HCl treated groups, cells showed more elongated and spindle - like appearance.