• Title/Summary/Keyword: period of active growth

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AN EXPERIMENTAL STUDY ON THE EFFECT OF THE MANDIBULAR RETRACTIVE FORCE ON THE MANDIBULAR CONDYLE OF GROWING YOUNG DOG (하악 후방 견인력이 성장기 유견의 하악과두에 미치는 영향에 관한 실험적 연구)

  • Lim, Yong-Kyu;Yang, Won-Sik
    • The korean journal of orthodontics
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    • v.20 no.2
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    • pp.363-379
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    • 1990
  • The purpose of this study was to evaluate the effects of the mandibular retractive force on the mandibular condyle of growing dog. The experimental animals were six mongrel dogs of two-month old. Their deciduous dentition were completed. Two of them was used as control group, and experimental group was composed of remaining four. Head band and chin cup were made of cotton tape, and hooks are fabricated on the chin cup and had band for closed coil. Mandibular retractive force was 100g/side and chin cap appliance was used for 14 hours/day during night. Experimental group were sacrificed at 2, 4, 6, 8 weeks from beginning of the experiment. Right TMJ was prepared for histologic study and left TMJ was examined grossly for disc, fossa, and condyle. The conclusions are: 1. Two-month old control animal showed active cartilaginous growth on the mandibular condyle, therefore showed thick proliferative and hypertrophic zones. Remodeling process in the condyle head was observed in which there were bone resorption on the anterior surface and bone apposition on the posterior surface. 2. Four-month old control animal showed marked reduction of hypertrophic zone but the condylar bone remodeling was more pronounced. 3. In experimental group, there are marked reduction of hypertrophic zone at 4 weeks from beginning of experiment, and hypertrophic zone disappeared at posterior-superior portion of condyle in 6-week experimental animal. 8 week experimental animal showed slight recovery of hypertrophic zone. 4. In experimental group, bone deposition was increased at anterior surface of condyle, and bone resorption was increased at posterior surface of condyle. 5. In control group, the glenoid fossa and surrounding bone showed mainly bone apposition. But experimental group showed bone resorption at anterior surface of articular eminence and increased bone apposition at posterior surface of postglenoid spine. 6. No marked traumatic change was seen but 4 weeks and 8 weeks experimental animal showed flattening of posterior surperior condylar surface. Bone marrow of condyle showed minute focal bleeding in 2 weeks and 4 weeks experimental animal, and congestion and depression of hematopoietic bone marrow during all experimental period.

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Experimental Study of the Pancreatic Regeneration after Partial Pancreatectomy in Rat (취조직 재생능에 관한 실험)

  • Lee, M.S.;Lee, S.Y.
    • The Korean Journal of Pharmacology
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    • v.14 no.1_2
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    • pp.47-54
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    • 1978
  • Recently, a major resection of the pancreas has been carried out not only to treat carcinoma of pancreas but also chronic pancreatitis. But limited and often contradictory reports have been made on the exocrine effects after partial surgical pancreatectomy in mammals. It was suggested that the growth of the residual tissue in pancreatectomized rat is very active, because pancreas has the great power of regeneration after partial pancreatectomy, while others observed that rat pancreas after partial surgical resection revealed a perplexing mixture of atrophy and regeneration of acinar tissue. On the other hand, another results showed that the amount of insulin required to control diabetes after partial resection of pancreas is much greater than that needed after total pancreatectomy. Because the anti-insulin system, such as glucagon secretion and hypophyseoadrenal function, is probably depressed after total pancreatectomy. Furthermore, minimal resection line which will not influence the normal function of pancreas is not agreeable, such 75%, 80% or 95% resection of the total pancreas in rat. So far, studies on the exocrine function other than endocrine function after partial pancreatectomy have been limited. Therefore, the main purpose of this study is to examine the changes of exocrine as well as endocrine function of pancreas at the different time interval after 60% or 80% pancreatectomy in rats. The results summerized as follow: 1) In both 60% and 80% resected groups, a slight decrease of the total body weight was observed at a day after partial pancreatectomy in rats, but the body weight was continued to increase for following 100 days. 2) The weight of residual pancreas was continuously increased during experiment in both 60% and 80% resected groups. But the content of tissue protein in residual pancreas was significantly decreased comparing with those of resected pancreas. 3) The flow rate of pancreatico-biliary juice was significantly decreased immediately after pancreatectomy in both resected groups. But it was recovered to control level after a day in 60% resected group, after 30 days in 80% resected group. 4) The output of amylase and lipase in resected groups were significantly decreased right after pancreatectomy comparing with control group. In the 60% resected group, the output of amylase was recovered during the following 100 days after pancreatectomy, while lipase output in 3 days. However, in the 80% resected group, the output of amylase and lipase were not recovered during 100 days after pancreatectomy. 5) In order to examine the endocrine function, blood sugar level were examined at all experimental periods after partial pancreatectomy. There was no difference between control and 60% resected group in the sugar level. But in the 80% resected group the level was significantly incresed immediately after pancreatectomy, and reached the highest level at 3 days. Then it was decreased to control level during the next 10 days after pancreatectomy. The above results showed that in 60% resected group little changes were observed on pancreatic function, but severe functional impairments were observed in 80% resected group. This results suggested that the endocrine function was recovered within a short period, although the exocrine function was not recovered for a long time after 80% pancreatectomy in rats.

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An Overview on Vibration or Wave Therapy in Korea (진동, 파동치료에 관한 국내 연구 동향)

  • Lee, Jae Heung;Beag, Ji You;Chang, Sung Jin;Pil, Gam Mai
    • Journal of Korean Medical Ki-Gong Academy
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    • v.20 no.1
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    • pp.15-67
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    • 2020
  • Objective : The purpose of this study is to identify the trends of vibration(or wave) therapy in Korea, to actively utilize vibration(or wave) therapy, and to help research activities of vibration therapy in Korean Medicine. Methods : The following Korean words "진동기", "진동요법", "진동운동", "진동치료", "파동요법", "파동운동", "파동치료" were searched on three specialized search sites (RISS, NAL, DBpia). Trends of vibration therapy were analyzed through the selected researches suitable for this study among these searched researches in an overview format. Results : 1. A total of 8,116 studies were searched and a total of 365 studies were finally selected 2. From 2000 to 2019, when research began to increase in earnest, there were 17.45±10.28 studies per year, and the AGR(Average Annual Growth Rate) was 11.92%. 3. In the main field of research, the 'Medicine and Pharmacy' was the largest with 147(40.16%) studies. In the Middle Field, the 'Kinesiology' was the largest with 99(27.05%) studies. In the study design, 'RCT(Randomized Controlled trial)' was the largest with 138(47.75%) studies. In the Age Group, 'Youth' was the largest with 126(48.84%) studies. 4. The average of the number of participants was 24.90±17.44. 5. The most used Intervention was the 'WBV(Whole Body Vibration)' with 177(61.25%) studies. 6. The average of Intervention Period was 5.99±4.14 weeks, while the maximum was 36 weeks. 7. The journal that published the most research papers is 'K. J. of Sports Science(체육과학연구;13)', and the society is 'Rehabilitation Engineering And Assistive Technology Society of Korea(한국재활복지공학회; 14)'. The University that published the most dissertations is 'Sahmyook University(11)'. 8. The authors who published the most studies are Ju-Hwan O(8) as the main author and Tae Kyu Kwon(18) as the co-author (including the thesis Director). In an integrated analysis of the authors and co-authors, Tae Kyu Kwon published the most numerous studies(19) Conclusions : 1. The study of vibration or wave therapy has been increasing noticeably every year. 2. The major academic Fields studying vibration or wave therapy are the 'Kinesiologic Field', 'Physical Therapy Field', and 'Biomedical Engineering Field'. 3. The most chosen method of study design on vibration or wave treatment was 'RCT', and there was no significant change in the annual presentation rate. 4. Types of vibration or wave therapy could be classified as 'LVS(Local Vibration Stimulation)', 'WBV(Whole Body Vibration)', 'MV(Micro Vibration)', 'BV(Bio Vibration)' and 'SWV(Sound Wave Vibration)', and the study on Whole Body Vibration is most active. 5. Most of the studies of vibration or wave therapy were on musculoskeletal systems, but there were very few studies on internal diseases.

The Comparison of Influence of Difficulties in Nasal Breathing on Dentition between Different Facial Types (비호흡 장애가 치열에 미치는 영향에 관한 안모 형태별 비교 연구)

  • Lee, Myeong-Jin;Lee, Chang-Kon;Kim, Jong-Sup;Park, Jin-Ho;Chin, Byung-Rho;Lee, Hee-Kyung
    • Journal of Yeungnam Medical Science
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    • v.10 no.1
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    • pp.37-47
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    • 1993
  • It is commonly assumed that nasorespiratory function can exert a dramatic effect upon the development of the dentofacial complex. Specially, it has been stated that chronic nasal obstruction leads to mouth breathing, which causes altered tongue and mandibular positions. If this occurs during a period of active growth, the outcome is development of the "adenoid facies". Such patients characteristically manifest a vertically long lower third facial height, narrow alar bases, lip incompetence, a long and narrow maxillary arch and a greater than normal mandibular plane angle. But several authors have reported that so-called adenoid facies is not always associated with adenoids and mouth breathing, and that a particular type of dentition is not always found in mouth breathers with or without adenoids. Some authors have believed adenoids lead to mouth breathing in cases with particular facial characteristics and types of dentition. We assumed that the ability to adapt to individual's neuromuscular complex is various. So, we compared the difference of influence of mouth breathing between childrens who have different facial types. This study included 60 patients and they were divided into three groups by Rickett's facial type. Their dentition and tongue position were compared. The results are as follows. 1. There is a significant difference in arch width of upper molars between different facial types. Especially dolichofacial type patients have narrowest arch width. 2. There is a significant difference in tongue position between different facial types. Especially dolichofacial type patients have lowest positioned tongue.

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Investigation of Korean-Chinese Business Management Research (한(韓).중(中) 양국간(兩國簡)의 무역(貿易).경영(經營) 연구(硏究)에 관(關)한 문헌(文獻)적 고찰(考察) -1981년(年)부터 2004년(年)까지를 중심(中心)으로-)

  • Mun, Cheol-Ju;Kim, Yong-Jun;Park, Jung-Dong;Moon, Chul-Woo
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.38
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    • pp.327-376
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    • 2008
  • China is marking 9.4% annual growth rate in average since 1978. GDP reached $1090 in 2003 as the first time and China ranked at 4th with their economy size in 2006. One of the remarkable change in China is the extension of foreign open-door policy. China joined WTO in the end of 2001 and it strengthen the foundation of Chinese market economy structure and encouraged the inflow of foreign capital. While 400 of the 500 global corporations advanced into China, the economy trade has been rapidly increasing between Korea and China. The economy trade in both countries has been regularized since 1992 and the annual trade is tending upwards in last 15 years. Korean trade toward China reached 134,400 million which is increased 27 times compared with the total of 1982. In this period, Korean trade toward China marked 24.5% in Export increasing rate and 16.7% in import increasing rate. China became the 2nd biggest export country of Korea in 2001 and became the top in 2003. As the China foreign direct investment has been increasing rapidly, the number of Korean companies advanced into China has been remarkably increasing. By focusing on a thorough review of the nationally published documents of Korean-Chinese business management research during more than two decades (1981-2004), the present paper has been systematically classified and analyzed the current status of Korean-Chinese business management research. The paper raised some important issues regarding Korean-Chinese business management research and predominantly, its future prospects are outlined. In the paper, the documents which are registered in the Korean Academic Processing Foundation registration of journals and candidate registration of journals have been classified by: research purpose, main subject, research method and the results. Careful analysis among the research clarified the active and inactive business management research fields. This clarification enables us to get a better understanding of the current research of Korean-Chinese business management, and more importantly, it pointed out to the direction of future development of research. In addition, the systematic classification made by this paper may contribute to the decision making of subject index of Korean-Chinese business management research since there has been no classification standard of it until now.

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The Effects of Mechanical Stress on Alkaline Phosphatase Activity of MC3T3-E1 Cells (기계적 자극이 MC3T3-EI 세포의 Alkaline Phosphatase Activity에 미치는 영향)

  • BAE, Sung-Min;KYUNG, Hee-Moon;SUNG, Jae-Hyun
    • The korean journal of orthodontics
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    • v.26 no.3
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    • pp.291-299
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    • 1996
  • Orthodontic force is a mechanical stress controlling both of tooth movement and skeletal growth. The mechanical stress stimulate bone cells that may exert some influence on bone remodeling. The purpose of this study was to evaluate the difference in cellular activity depending on mechanical stresses such as compressive and tensile force by determining the alkaline phosphatase(ALP) activity. A clonal osteogenic cell line MC3T3-E1 was seeded into a 24-well plate($2{\times}10^4/well$). At the confluent phase, a continuous compressive hydrostatic pressure($25g/cm^2$, $300g/cm^2$) and continuous tensile hydrostatic pressure($-25g/cm^2$, $-300g/cm^2$) were applied for 4, 6, 10, 14, 18, 20 days respectively by a diaphgragm pump. At the end of the stimulation period, cell layers were prepared for ALP activity assay. The ALP activity of the compressive group increased more than that of the tensile group at same force magnitude, whereas the cells responded to a similar pattern regardless of the type of mechanical stress The ALP activity of the compressive and tensile group turned into the level of the control group as the length of time increased. These results indicated that a mechanical stress may be more effective on cellular activity during active cellular proliferation and differentiation periods. The time to achieve maximum ALP activity was delayed as the mechanical stress increased in both the compressive and the tensile group. Accordingly, the magnitude of the stress rather than the type of mechanical stress may have more influence on cellular activity.

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Current Status and Perspectives of Quality Improvement in Sesame (참깨 품질 연구의 현황과 문제점 및 전망)

  • Lee, Bong-Ho;Lee, Jung-Il;Park, Rae-Kyeong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.33 no.s01
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    • pp.86-97
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    • 1988
  • Sesame(Sesamum indicum L.) is probably the most ancient oilseed crop known in the world. The seed of sesame is used in a variety of ways as food. The whole seed may be eaten raw, either roasted or parched, or fed to birds and stock. Sesame oil is used as a salad or cooking oil, in shortening, margarine and in the manufacture of soap. Minor uses are as a fixative in the perfume industry and formerly as a carrier for fatsoluble substances in pharmaceuticals such as penicillin. One of the minor constituents of sesame oil, sesamin, is used for its synergistic effect in pyrethrin insecticides, in addition of a small quantity of this substance markedly increases the effectiveness of fly sprays. The meal remaining after oil extraction can be used as and animal feed-stuff or as manure. In general sesame meal is considered to be equal to cottonseed or soybean meal as a protein supplement for livestock and poultry. It is especially high in certain amino-acids such as methionine, which is low in soybean meal, and thus can be combined with it or similar meal to form a more balanced ration. An attempt to summarize the literature review on quality improvement of sesame was made to discuss the accomplishments of the past and perspectives in the future. The reviews on quality improvement of sesame were mainly discussed in connection with the cultural practices and genetic informations in current status. The emphasis focussed on environmental variation of quality in cultural practices, such as harvest time, variety by location, climatic condition, fertilizer application, and growth regulator treatment. On the genetic variation of quality, it was discussed on variety background, mutation breeding, correlations, and inheritance of quality related characteristics. It also was discussed on relationship between quality and plant traits, storage condition or period, and seed coat color. Moreover, current research status were reviewed on some minor elements such as sesamin, oxalic acid, and trypsin inhibitor. As a results of the review, the lack of an effort to quality improvement in each utilization area was indicated as a problem area. More active efforts for the improvement of quality were also insufficient to incorporate the available genes for quality in breeding method or collection and analysis of breeding materials. Therefore, researches in the future would be recommended to emphasize on these problem areas.

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Keyword Analysis of Research on Consumption of Children and Adolescents Using Text Mining (텍스트마이닝을 활용한 아동, 청소년 대상 소비관련 연구 키워드 분석)

  • Jin, Hyun-Jeong
    • Journal of Korean Home Economics Education Association
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    • v.33 no.4
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    • pp.1-13
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    • 2021
  • The purpose of this study is to identify trends and potential themes of research on consumption of children and adolescents for 20 years by analyzing keywords. The keywords of 869 studies on consumption of children and adolescents published in journals listed in Korean Citation Index were analyzed using text mining techniques. The most frequent keywords were found in the order of youth, youth consumers, consumer education, conspicuous consumption, consumption behavior, and character. As a result of analyzing the frequency of keywords by dividing into five-year periods, it was confirmed that the frequency of consumer education was significantly higher betwn 2006 and 2010. Research on ethical consumption has been active since 2011, and research has been conducted on various topics instead of without a prominent keyword during the most recent 5-year period. Looking at the keywords based on the TF-IDF, the keywords related to the environment and the Internet were the main keywords between 2001 and 2005. From 2006 to 2010, the TF-IDF values of media use, advertisement education, and Internet items were high. From 2011 to 2015, fair trade, green growth, green consumption, North Korean defector youths, social media, and from 2016 to 2020, text mining, sustainable development education, maker education, and the 2015 revised curriculum appeared as important themes. As a result of topic modeling, eight topics were derived: consumer education, mass media/peer culture, rational consumption, Hallyu/cultural industry, consumer competency, economic education, teaching and learning method, and eco-friendly/ethical consumption. As a result of network analysis, it was found that conspicuous consumption and consumer education are important topics in consumption research of children and adolescents.

Elementary Teachers' Perception, Practice, and Background Factors in Using Students' Everyday Experience in Teaching Science (과학수업에서 학생의 일상경험 도입에 대한 초등교사의 인식과 실행 및 배경요인)

  • Na, Jiyeon;Song, Jinwoong
    • Journal of The Korean Association For Science Education
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    • v.34 no.7
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    • pp.635-645
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    • 2014
  • The purpose of this study is to identify elementary school teachers' perceptions, practices, and background factors related to introducing students' everyday experience in science teaching process. The participants of this study were four elementary school teachers who have different features such as major, teaching period, gender, growth area, and age. The data was collected through semi-constructed and in-depth interviews. The results of the research are as follows: Teachers mostly used students' everyday experience during the introduction phase of science lessons for the purpose of motivation. They hold a positive view of using students' everyday experience during science lessons and thought that science teaching needs to actively use more of students' everyday experience, while in actual practice they disregarded or only passively introduced students' everyday experience. The various background factors found to affect teachers' practice are as follows: positive memory on their science class; educational experience of their own children; their own childhood environment; their learning style; their insufficient knowledge or enthusiasm; perceived educational value of everyday life in science education; teacher's duties; importance of students' achievement; difficulty in guiding experiment; reaction of students on introducing everyday experience; characteristics of science textbook and teacher's guidebook; lack of lesson time; realization of national common basic education; characteristics of their students; demands from parents or students; effect of introducing everyday experience. In addition, we found that the teachers behave not in accordance with what they thought due to external factors related to their profession and that, for a more active use of students' everyday experience in their teaching, teachers need support from textbooks and teachers' guidebooks.

Effect of highly activated calcium on the growth of mushrooms (고활성칼슘의 버섯 생육에 대한 효과)

  • Chang, Hyun-You;Goo, Ja-Joon
    • Journal of Mushroom
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    • v.3 no.1
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    • pp.35-39
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    • 2005
  • Highly Activated Calcium(below HAC) is the oxidized calcium made by dissolving shell materials with high voltage about 15,000V and high temperature ($1,500{\sim}5,000^{\circ}C$). This HAC is a material with a very high degree of purity without toxicant. This HAC decreases chemical reaction so the degree of being active and dissolving living material is outstanding. The effects of HAC on the propagation of mushrooms are following. In the case of the Pleurotus ostreatus, when controlling media moisture by mixing with the HAC, mycelium cultivating days were shortened by 2days. The day required for primordial formation after inoculation(DPI) were one day faster. The number of stem was 15 and individual weight was 248g/850cc, a 6.5% increase. In the case of Pleurotus eryngii, when controlling media moisture by mixing with the highly activated calcium, mycelium cultivating days were shortened by 3days. DPI were l day faster. The day required for colonization after inoculation was shortened by 6days and individual weight was 108.8g/850cc, a 9.7% increase. In the case of Flammulina velutipes, the highly activated calcium was the best for scraping up mycelium. Mycelium incubating days were shortened by 2days. DPI were shortened by 3days. The day required for colonization after inoculation was 1day faster and the period of cultivation was shortened by 3days. Individual weight was 165g/850cc, a 6.7% increase. In the case of Lentinula edodes, when mixing media with the highly cultivated calcium, cultivating days were shortened by 3 days. The days for becoming brown in color were 2 days faster and the days of the first harvest were shortened by 4 days. The weight of mushrooms was 169g/2kg, a 9.7% increase.

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