• Title/Summary/Keyword: field study

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Inhomogeneity correction in on-line dosimetry using transmission dose (투과선량을 이용한 온라인 선량측정에서 불균질조직에 대한 선량 보정)

  • Wu, Hong-Gyun;Huh, Soon-Nyung;Lee, Hyoung-Koo;Ha, Sung-Whan
    • Journal of Radiation Protection and Research
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    • v.23 no.3
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    • pp.139-147
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    • 1998
  • Purpose: Tissue inhomogeneity such as lung affects tumor dose as well as transmission dose in new concept of on-line dosimetry which estimates tumor dose from transmission dose using the new algorithm. This study was carried out to confirm accuracy of correction by tissue density in tumor dose estimation utilizing transmission dose. Methods: Cork phantom (CP, density $0.202\;gm/cm^3$) having similar density with lung parenchyme and polystyrene phantom (PP, density $1.040\;gm/cm^3$) having similar density with soft tissue were used. Dose measurement was carried out under condition simulating human chest. On simulating AP-PA irradiation, PPs with 3 cm thickness were placed above and below CP, which had thickness of 5, 10, and 20 cm. On simulating lateral irradiation, 6 cm thickness of PP was placed between two 10 cm thickness CPs additional 3 cm thick PP was placed to both lateral sides. 4, 6, and 10 MV x-ray were used. Field size was in the range of $3{\times}3$ cm through $20{\times}20$ cm, and phantom-chamber distance (PCD) was 10 to 50 cm. Above result was compared with another sets of data with equivalent thickness of PP which was corrected by density. Result: When transmission dose of PP was compared with equivalent thickness of CP which was corrected with density, the average error was 0.18 (${\pm}0.27$) % for 4 MV, 0.10 (${\pm}0.43$) % for 6 MV, and 0.33 (${\pm}0.30$) % for 10 MV with CP having thickness of 5 cm. When CP was 10 cm thick, the error was 0.23 (${\pm}0.73$) %, 0.05 (${\pm}0.57$) %, and 0.04 (${\pm}0.40$) %, while for 20 cm, error was 0.55 (${\pm}0.36$) %, 0.34 (${\pm}0.27$) %, and 0.34 (${\pm}0.18$) % for corresponding energy. With lateral irradiation model, difference was 1.15 (${\pm}1.86$) %, 0.90 (${\pm}1.43$) %, and 0.86 (${\pm}1.01$) % for corresponding energy. Relatively large difference was found in case of PCD having value of 10 cm. Omitting PCD with 10 cm, the difference was reduced to 0.47 (${\pm}$1.17) %, 0.42 (${\pm}$0.96) %, and 0.55 (${\pm}$0.77) % for corresponding energy. Conclusion When tissue inhomogeneity such as lung is in tract of x-ray beam, tumor dose could be calculated from transmission dose after correction utilizing tissue density.

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The Increased Expression of Gelatinolytic Proteases Due to Cigarette Smoking Exposure in the Lung of Guinea Pig (기니픽에서 흡연 노출에 의한 젤라틴 분해 단백 효소의 발현 양상에 관한 연구)

  • Kang, Min-Jong;Lee, Jae-Ho;Yoo, Chul-Gyu;Lee, Choon-Taek;Chung, Hee-Soon;Seo, Jeong-Wook;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo
    • Tuberculosis and Respiratory Diseases
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    • v.50 no.4
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    • pp.426-436
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    • 2001
  • Background : Chronic obstructive pulmonary disease(COPD) is one of the major contributors to morbidity and mortality among the adult population. Cigarette smoking(CS) is undoubtedly the single most important factor in the pathogenesis of COPD. However, its mechanism is unclear. The current hypothesis regarding the pathogenesis of COPD postulates that an imbalance between proteases and antiproteases leads to the destructive changes in the lung parenchyma. This study had two aims. First, to evaluate the effect of CS exposure on histologic changes of the lung parenchyme, and second, to evaluate the effect of CS exposure on the expression of the gelatinolytic enzymes in BAL fluid cells in guinea pigs. Methods : Two groups of five guinea pigs were exposed to the whole smoke of 20 commercial cigarettes per day, 5 hours/day, 5 days/week, for 6weeks, and 12 weeks, respectively, using a smoking apparatus. Five age-matched guinea pigs exposed to room air were used as controls. Five or more sections were microscopically extamined(${\times}400$) and the number of cellular infiltration of the alveolar wall was measured in order to evaluate the effect of CS exposure on the histologic changes of lung parenchyme. The statistical significance was analyzed by a linear regression method. To evaluate the expression of the gelatinolytic enzymes in intraalveolar cells, BAL fluid was obtained and the intraalveolar cells were separated by centrifugation (500 g for 10 min at $4^{\circ}C$). Two sets of culture plates were loaded with $1{\times}10^6$ intraalveolar cells. One plate, contained O.1mM EDTA, a inhibitor of matrix metalloproteases(MMPs), and the other plate had no EDTA. Both plates were incubated for 48 hours at $37^{\circ}C$. After incubation, gelatinolytic protease expression in the supernatants was analyzed by gelatin zymography. Results : At the end of CS exposure, the level of blood carboxy Hb had increased significantly(4.1g/dl in control group, 24g/dl immediately after CS exposure, 18g/dl 30 min after CS exposure, 15g/dl 1 hour after CS exposure). Alveolar inflammatory cells were identified in the CS exposed guinea pigs. The number of alveolar cellular cells observed in a microscopic field ($400{\times}$) was $121.4{\pm}7.2$, $158.0{\pm}20.2$, $196.8{\pm}32.8$, in the control, the 6 weeks, and the 12 weeks group, respectively. The increased extent of inflammatory cellular infiltration of the lung parenchema showed a statistically significant linear relationship with the duration of CS exposure(p=0.001, $r^2=0.675$). Several types of gelatinolytic enzymes in the intraalveolar cells of CS exposed guinea pigs were expressed, of which some were inhibited by EDT A. However, the gelatinolytic enzymes were not expressed in the control groups. Conclusion : CS exposure increases inflammatory cellular infiltration of the alveolar wall and the expression of gelatinolytic proteases in guinea pigs. EDTA inhibits some of the gelatinolytic proteases. These findings suggest a possibility that CS exposure may increase MMP expression in the lungs of guinea pigs.

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A study of the Medical System in the Early Chosun-Dynasty (조선시대(朝鮮時代) 전기(前期)의 의료제도(醫療制度)에 대한 연구(硏究))

  • Han, Dae-Hee;Kang, Hyo-Shin
    • Journal of Korean Medical classics
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    • v.9
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    • pp.555-652
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    • 1996
  • Up to the present the scholastic achievements in the history of the medical system have been rather scare despite its importance in the Korean History. Hence, this dissertation attempts to examine the significance of the institute in the Korean History, covering the period from the ancient times through the early Chosun-Dynasty. In the ancient times, the medical practice relied primarily upon human instincts and experiences at the same time, shaman's incantations were widely believed to cure diseases, the workings of evil spirits supposedly. For the period from the Old Chosun through Samhan(巫堂), Chinese refugees brought a long medical knowledge and skills of the continent. New Chinese medicine, traditional practices and incantations were generally used at this time. Medicine and the medical system were arranged by the period of the Three Countries(三國時代). No definite record concerning Koguryo remains now. As for Paekje, however, history shows that they set up the system under the Chinese influence, assigning medical posts such as Euibaksa(medical doctor), Chaeyaksa(pharmacist), and Jukeumsa(medicine man) within Yakbu(department of medicine). Scientifically advanced, they sent experts to Japan, giving a tremendous influence on the development of the science on ancient Japan. After the unification of the three countries, Shilla had their own system after the model of Dang(唐). This system of the Unified Shilla was continued down to Koryo and became the backbone of the future ones. In the ancient time religion and medicine were closely related. The curative function of the shaman was absolute. Buddhism played a notable part in medical practice, too, producing numerous medical monks. The medical system of Koryo followed the model of Dang with some borrowings from Song(宋). Sangyakkuk(尙藥局) was to deal exclusively with the diseases of the monarch whereas Taeeuigam(太醫監) was the central office to handle the national medical administration and the qualification test and education for doctors. In addition, Dongsodaebiwon(東西大悲院), Jewibo(濟危寶), and Hyeminkuk(惠民局) were public hospitals for the people, and a few aristocrats practiced medicine privately. In 987, the 6th year of Songjong(成宗), local medical operations were installed for curing the sick and educating medical students. Later Hyonjong(顯宗), established Yakjom(clinics, 藥店) throughout the country and officials were sent there to see patients. Foreign experts, mainly from Song, were invited frequently to deliver their advanced technology, and contributed to the great progress of the science in Korea. Medical officials were equipped with better land and salary than others, enjoying appropriate social respect. Koryo exchanged doctors, medicine and books mainly with Song, but also had substantial interrelations with Yuan(元), Ming(明), Kitan(契丹), Yojin(女眞), and Japan. Among them, however, Song was most influential to the development of medicine in Koryo. During Koryo Dynasty Buddhism, the national religion at the time, exercised bigger effect on medicine than in any other period. By conducting national ceremonies and public rituals to cure diseases, Taoism also affected the way people regarded illness. Curative shamanism was still in practice as well. These religious practices, however, were now engaged only when medication was already in use or when medicine could not held not help any more. The advanced medical system of Koryo were handed down to Chosun and served the basis for further progress. Hence, then played well the role to connect the ancient medicine and the modern one. The early Chosun followed and systemized the scientific and technical achievement in medicine during the Koryo Dynasty, and furthermore, founded the basis of the future developments. Especially the 70 years approximately from the reign of Sejong(世宗) to that of Songjong(成宗) withnessed a termendous progress in the field with the reestablishment of the medical system. The functions of the three medical institute Naeeuiwon(內醫院), Joneuigam(典醫監), Hyeminkuk(惠民局) were expanded. The second, particualy, not only systemized all the medical practices of the whole nation, but also grew and distributed domestic medicaments which had been continually developed since the late Koryo period. In addition, Hyeminso(惠民局, Hwarinwon(活人院)) and Jesaenwon(濟生院)(later merged to the first) played certain parts in the curing illness. Despite the active medical education in the capital and the country, the results were not substantial, for the aristocracy avoided the profession due to the social prejudice against technicians including medical docotors. During the early Chosun-Dynasty, the science was divided into Chimgueui (acupuncturist), Naryogeui(specialist in scrofula) and Chijongeui (specialist in boil). For the textbooks, those for the qualification exam were used, including several written by the natives. With the introduction on Neoconfucianism(性理學) which reinforced sexual segregation, female doctors appeared for the female patients who refused to be seen by male doctors. This system first appeared in 1406, the sixth year of Taejong(太宗), but finally set up during the reign of Sejong. As slaves to the offices, the lowest class, female doctors drew no respect. However, this is still significant in the aspect of women's participation in society. They were precedents of midwives. Medical officials were selected through the civil exam and a special test. Those who passed exams were given temporary jobs and took permanent posts later. At that time the test score, the work experience and the performance record of the prospective doctor were all taken into consideration, for it was a specialized office. Most doctors were given posts that changed every six months, and therefore had fewer chances for a goverment office than the aristocracy. At the beginning the social status of those in medicine was not that low, but with the prejudice gradully rising among the aristocracy, it became generally agreed to belong to the upper-middle technician class. Dealing with life, however, they received social respect and courtesy from the public. Sometimes they collected wealth with their skills. They kept improving techniques and finally came to take an important share in modernization process during the late Chosun-Dynasty.

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The Impact of Bladder Volume on Acute Urinary Toxicity during Radiation Therapy for Prostate Cancer (전립선암의 방사선치료시 방광 부피가 비뇨기계 부작용에 미치는 영향)

  • Lee, Ji-Hae;Suh, Hyun-Suk;Lee, Kyung-Ja;Lee, Re-Na;Kim, Myung-Soo
    • Radiation Oncology Journal
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    • v.26 no.4
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    • pp.237-246
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    • 2008
  • Purpose: Three-dimensional conformal radiation therapy (3DCRT) and intensity-modulated radiation therapy (IMRT) were found to reduce the incidence of acute and late rectal toxicity compared with conventional radiation therapy (RT), although acute and late urinary toxicities were not reduced significantly. Acute urinary toxicity, even at a low-grade, not only has an impact on a patient's quality of life, but also can be used as a predictor for chronic urinary toxicity. With bladder filling, part of the bladder moves away from the radiation field, resulting in a small irradiated bladder volume; hence, urinary toxicity can be decreased. The purpose of this study is to evaluate the impact of bladder volume on acute urinary toxicity during RT in patients with prostate cancer. Materials and Methods: Forty two patients diagnosed with prostate cancer were treated by 3DCRT and of these, 21 patients made up a control group treated without any instruction to control the bladder volume. The remaining 21 patients in the experimental group were treated with a full bladder after drinking 450 mL of water an hour before treatment. We measured the bladder volume by CT and ultrasound at simulation to validate the accuracy of ultrasound. During the treatment period, we measured bladder volume weekly by ultrasound, for the experimental group, to evaluate the variation of the bladder volume. Results: A significant correlation between the bladder volume measured by CT and ultrasound was observed. The bladder volume in the experimental group varied with each patient despite drinking the same amount of water. Although weekly variations of the bladder volume were very high, larger initial CT volumes were associated with larger mean weekly bladder volumes. The mean bladder volume was $299{\pm}155\;mL$ in the experimental group, as opposed to $187{\pm}155\;mL$ in the control group. Patients in experimental group experienced less acute urinary toxicities than in control group, but the difference was not statistically significant. A trend of reduced toxicity was observed with the increase of CT bladder volume. In patients with bladder volumes greater than 150 mL at simulation, toxicity rates of all grades were significantly lower than in patients with bladder volume less than 150 mL. Also, patients with a mean bladder volume larger than 100 mL during treatment showed a slightly reduced Grade 1 urinary toxicity rate compared to patients with a mean bladder volume smaller than 100 mL. Conclusion: Despite the large variability in bladder volume during the treatment period, treating patients with a full bladder reduced acute urinary toxicities in patients with prostate cancer. We recommend that patients with prostate cancer undergo treatment with a full bladder.

Study on 3D Printer Suitable for Character Merchandise Production Training (캐릭터 상품 제작 교육에 적합한 3D프린터 연구)

  • Kwon, Dong-Hyun
    • Cartoon and Animation Studies
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    • s.41
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    • pp.455-486
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    • 2015
  • The 3D printing technology, which started from the patent registration in 1986, was a technology that did not attract attention other than from some companies, due to the lack of awareness at the time. However, today, as expiring patents are appearing after the passage of 20 years, the price of 3D printers have decreased to the level of allowing purchase by individuals and the technology is attracting attention from industries, in addition to the general public, such as by naturally accepting 3D and to share 3D data, based on the generalization of online information exchange and improvement of computer performance. The production capability of 3D printers, which is based on digital data enabling digital transmission and revision and supplementation or production manufacturing not requiring molding, may provide a groundbreaking change to the process of manufacturing, and may attain the same effect in the character merchandise sector. Using a 3D printer is becoming a necessity in various figure merchandise productions which are in the forefront of the kidult culture that is recently gaining attention, and when predicting the demand by the industrial sites related to such character merchandise and when considering the more inexpensive price due to the expiration of patents and sharing of technology, expanding opportunities and sectors of employment and cultivating manpower that are able to engage in further creative work seems as a must, by introducing education courses cultivating manpower that can utilize 3D printers at the education field. However, there are limits in the information that can be obtained when seeking to introduce 3D printers in school education. Because the press or information media only mentions general information, such as the growth of the industrial size or prosperous future value of 3D printers, the research level of the academic world also remains at the level of organizing contents in an introductory level, such as by analyzing data on industrial size, analyzing the applicable scope in the industry, or introducing the printing technology. Such lack of information gives rise to problems at the education site. There would be no choice but to incur temporal and opportunity expenses, since the technology would only be able to be used after going through trials and errors, by first introducing the technology without examining the actual information, such as through comparing the strengths and weaknesses. In particular, if an expensive equipment introduced does not suit the features of school education, the loss costs would be significant. This research targeted general users without a technology-related basis, instead of specialists. By comparing the strengths and weaknesses and analyzing the problems and matters requiring notice upon use, pursuant to the representative technologies, instead of merely introducing the 3D printer technology as had been done previously, this research sought to explain the types of features that a 3D printer should have, in particular, when required in education relating to the development of figure merchandise as an optional cultural contents at cartoon-related departments, and sought to provide information that can be of practical help when seeking to provide education using 3D printers in the future. In the main body, the technologies were explained by making a classification based on a new perspective, such as the buttress method, types of materials, two-dimensional printing method, and three-dimensional printing method. The reason for selecting such different classification method was to easily allow mutual comparison of the practical problems upon use. In conclusion, the most suitable 3D printer was selected as the printer in the FDM method, which is comparatively cheap and requires low repair and maintenance cost and low materials expenses, although rather insufficient in the quality of outputs, and a recommendation was made, in addition, to select an entity that is supportive in providing technical support.

Effect of Additional 1 hour T-piece Trial on Weaning Outcome to the Patients at Minimum Pressure Support (최소압력보조 수준에서 추가적 1시간 T-piece 시도가 이탈에 미치는 영향)

  • Hong, Sang-Bum;Koh, Youn-Suck;Lim, Chae-Man;Ann, Jong-Jun;Park, Wann;Shim, Tae-Son;Lee, Sang-Do;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.4
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    • pp.813-822
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    • 1998
  • Background: Extubation is recommended to be performed at minimum pressure support (PSmin) during the pressure support ventilation (PSV). In field, physicians sometimes perform additional 1 hr T-piece trial to the patient at PSmin to reduce re-intubation risk. Although it provides confirmation of patient's breathing reserve, weaning could be delayed due to increased airway resistance by endotracheal tube. Methods: To investigate the effect of additional 1 hr T-piece trial on weaning outcome, a prospective study was done in consecutive 44 patients who had received mechanical ventilation more than 3 days. Respiratory mechanics, hemodymic, and gas exchange measurements were done and the level of PSmin was calculated using the equation (PSmin=peak inspiratory flow rate $\times$ total ventilatory system resistance) at the 15cm $H_2O$ of pressure support. At PSmin, the patients were randomized into intervention (additional 1 hr T-piece trial) and control (extubation at PSmin). The measurements were repeated at PSmm, during weaning process (in cases of intervention), and after extubation. The weaning success was defined as spontaneous breathing more than 48hr after extubation. In intervention group, failure to continue weaning process was also considered as weaning failure. Results: Thirty-six patients with 42 times weaning trial were satisfied to the protocol. Mean PSmin level was 7.6 (${\pm}1.9$)cm $H_2O$. There were no differences in total ventilation times (TVT), APACHE III score, nutritional indices, and respiratory mechanics at PSmin between 2 groups. The weaning success rate and re-intubation rate were not different between intervention group (55% and 18% in each) and control group (70% and 20% in each) at first weaning trial. Work of breathing, pressure time product, and tidal volume were aggravated during 1 hr T-piece trial compared to those of PSmin in intervention group ($10.4{\pm}1.25$ and $1.66{\pm}1.08$ J/L in work of breathing) ($191{\pm}232$ and $287{\pm}217$cm $H_2O$ s/m in pressure time product) ($0.33{\pm}0.09$ and $0.29{\pm}0.09$ L in tidal volume) (P<0.05 in each). As in whole, TVT, and tidal volume at PSmin were significantly different between the patients with weaning success ($246{\pm}195$ hr, $0.43{\pm}0.11$ L) and the those with weaning failure ($407{\pm}248$ hr, $0.35{\pm}0.10$L) (P<0.05 in each). Conclusion : There were no advantage to weaning outcome by addition of 1 hr T-piece trial compared to prompt extubation to the patient at PS min.

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Requirement and Perception of Parents on the Subject of Home Economics in Middle School (중학교 가정교과에 대한 학부모의 인식 및 요구도)

  • Shin Hyo-Shick;Park Mi-Soog
    • Journal of Korean Home Economics Education Association
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    • v.18 no.3 s.41
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    • pp.1-22
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    • 2006
  • The purpose of this study is that I should look for a desirous directions about home economics by studying the requirements and perception of the high school parents who have finished the course of home economics. It was about 600 parents whom I have searched Seoul-Pusan, Ganwon. Ghynggi province, Choongcheong-Gyungsang province, Cheonla and Jeju province of 600, I chose only 560 as apparently suitable research. The questions include 61 requirements about home economics and one which we never fail to keep among the contents, whenever possible and one about the perception of home economics aims 11 about the perception of home economics courses and management. The collections were analyzed frequency, percent, mean. standard deviation t-test by using SAS program. The followings is the summary result of studying of it. 1. All the boys and girls learning together about the Idea of healthy lives and desirous human formulation and knowledge together are higher. 2. Among the teaching purposes of home economics, the item of the scientific principle and knowledge for improvements of home life shows 15.7% below average value. 3. The recognition degree about the quality of home economics is highly related with the real life, and about the system. we recognize lacking in periods and contents of home economics field and about guiding content, accomplishment and application qualities are higher regardless of sex. 4. The important term which we should emphasize in the subject of home economics is family part. 5. Among the needs of home economic requirement in freshman, in the middle unit, their growth and development are higher than anything else, representing 4.11, and by contrast the basic principle and actuality is 3.70, which is lowest among them. 6. In the case of second grade requirement of home economics content for parents in the middle unit young man and consuming life is 4.09 highest. 7. In the case of 3rd grade requirement of economics contents in the middle unit the choice of coming direction and job ethics is highest 4.16, and preparing meals and evaluation is lowest 3.50.

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Preparation of Vitamin E Acetate Nano-emulsion and In Vitro Research Regarding Vitamin E Acetate Transdermal Delivery System which Use Franz Diffusion Cell (Vitamin E Acetate를 함유한 Nano-emulsion 제조와 Franz Diffusion Cell을 이용한 Vitamin E Acetate의 경표피 흡수에 관한 In Vitro 연구)

  • Park, Soo-Nam;Kim, Jai-Hyun;Yang, Hee-Jung;Won, Bo-Ryoung;Ahn, You-Jin;Kang, Myung-Kyu
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.35 no.2
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    • pp.91-101
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    • 2009
  • in the cosmetics and medical supply field as a antioxidant material. The stable nano particle emulsion of skin toner type containing VEA was prepared. To evaluate the skin permeation, experiments on VEA permeation to the skin of the ICR outbred albino mice (12 weeks, about 50 g, female) and on differences of solubility as a function of receptor formulations was performed. The analysis of nano-emulsions containing VEA 0.07 % showed that the higher ethanol contents the larger emulsions were formed, while the higher surfactant contents the size became smaller.In this study, vitamin E acetate (VEA, tocopheryl acetate), a lipid-soluble vitamin which is widely used A certain contents of ethanol in receptor phase increased VEA solubility on the nano-emulsion. When the ethanol contents were 10.0 % and 20.0 %, the VEA solubility was higher than 5.0 % and 40.0 %, respectively. The type of surfactant in receptor solution influenced to VEA solubility. The comparison between three kind surfactants whose chemical structures and HLB values are different, showed that solubility of VEA was increased as order of sorbitan sesquioleate (Arlacel 83; HLB 3.7) > POE (10) hydrogenated castor oil (HCO-10; HLB 6.5) > sorbitan monostearate (Arlacel 60; HLB 4.7). VEA solubility was also shown to be different according to the type of antioxidant. In early time, the solubility of the sample including ascorbic acid was similar to those of other samples including other types of antioxidants. However, the solubility of the sample including ascorbic acid was 2 times higher than others after 24 h. Franz diffusion cell experiment using mouse skin was performed with four nano-emulsion samples which have different VEA contents. The emulsion of 10 wt% ethanol was shown to be the most permeable at the amount of 128.8 ${\mu}g/cm^2$. When the result of 10 % ethanol content was compared with initial input of 220.057 ${\mu}g/cm^2$, the permeated amount was 58.53 % and the permeated amount at 10 % ethanol was higher 45.0 % and 15.0 % than the other results which ethanol contents were 1.0 and 20.0 wt%, respectively. Emulsion particle size used 0.5 % surfactant (HCO-60) was 26.0 nm that is one twentieth time smaller than the size of 0.007 % surfactant (HCO-60) at the same ethanol content. Transepidermal permeation of VEA was 54.848 ${\mu}g/cm^2$ which is smaller than that of particlesize 590.7 nm. Skin permeation of nano-emulsion containing VEA and difference of VEA solubility as a function of receptor phase formulation were determined from the results. Using these results, optimal conditions of transepidermal permeation with VEA were considered to be set up.

DC Resistivity method to image the underground structure beneath river or lake bottom (하저 지반특성 규명을 위한 전기비저항 탐사)

  • Kim Jung-Ho;Yi Myeong-Jong;Song Yoonho;Cho Seong-Jun;Lee Seong-Kon;Son Jeongsul
    • 한국지구물리탐사학회:학술대회논문집
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    • 2002.09a
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    • pp.139-162
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    • 2002
  • Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.

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Cultural Practices of In vitro Tuber of Pinellia ternata(Thunb.) Breit I. Effects of Planting Time on Growth, Tuber Formation and Yield (기내(器內) 대량(大量) 생산(生産) 반하(半夏) 종구(種球)의 포장(圃場) 재배기술(裁培技術) 연구(硏究) I. 파종시기(播種詩期)가 생육(生育)과 괴경형성(塊莖形成) 및 수량(收量)에 미치는 영향(影響))

  • Park, Ho-Ki;Kim, Tai-Soo;Park, Moon-Soo;Choi, In-Leok;Jang, Yeong-Sun;Park, Keun-Yong
    • Korean Journal of Medicinal Crop Science
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    • v.1 no.2
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    • pp.109-114
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    • 1993
  • This study was carried out to determine the optimum planting time for in vitromultiplied tuber of Pinellia ternata(Thunb.) Breit. The tubers were planted on April 20, May 20, June 20, July 20, August 20 and September 20 in 1990. Emergence ratios were 68 to 87% in any planting time except planting on July 20. The number of tubers per $m^2$ at harvest in plantings on May 20 and June 20 were significantly higher with 1,110 and 1,021, respectively, while in plantings after July 20, those were drastically decreased. As compared with fresh yield of planting on April 20(352kg /10a), that of May 20 was 109% and June 20 was 103%, while those of after July 20 were from 41% to 19%. There was a highly positive correlation between dry tuber yield and the number of tubers per $m^2(r=0.991^{**})$. Tuber yields for commercial use(diameter over 7.1mm) were high in planting on May 20(322kg /10a) and on June 20(299kg /10a). It was suggested that optimum field planting time for in vitro multiplied tuber of Pinellia ternata(Thunb.) Breit was from May 20 to June May 20.

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