• Title/Summary/Keyword: Standard Formation

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The Effect of the Surfactant on the Migration and Distribution of Immiscible Fluids in Pore Network (계면활성제가 공극 구조 내 비혼성 유체의 거동과 분포에 미치는 영향)

  • Park, Gyuryeong;Kim, Seon-Ok;Wang, Sookyun
    • Economic and Environmental Geology
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    • v.54 no.1
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    • pp.105-115
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    • 2021
  • The geological CO2 sequestration in underground geological formation such as deep saline aquifers and depleted hydrocarbon reservoirs is one of the most promising options for reducing the atmospheric CO2 emissions. The process in geological CO2 sequestration involves injection of supercritical CO2 (scCO2) into porous media saturated with pore water and initiates CO2 flooding with immiscible displacement. The CO2 migration and distribution, and, consequently, the displacement efficiency is governed by the interaction of fluids. Especially, the viscous force and capillary force are controlled by geological formation conditions and injection conditions. This study aimed to estimate the effects of surfactant on interfacial tension between the immiscible fluids, scCO2 and porewater, under high pressure and high temperature conditions by using a pair of proxy fluids under standard conditions through pendant drop method. It also aimed to observe migration and distribution patterns of the immiscible fluids and estimate the effects of surfactant concentrations on the displacement efficiency of scCO2. Micromodel experiments were conducted by applying n-hexane and deionized water as proxy fluids for scCO2 and porewater. In order to quantitatively analyze the immiscible displacement phenomena by n-hexane injection in pore network, the images of migration and distribution pattern of the two fluids are acquired through a imaging system. The experimental results revealed that the addition of surfactants sharply reduces the interfacial tension between hexane and deionized water at low concentrations and approaches a constant value as the concentration increases. Also it was found that, by directly affecting the flow path of the flooding fluid at the pore scale in the porous medium, the surfactant showed the identical effect on the displacement efficiency of n-hexane at equilibrium state. The experimental observation results could provide important fundamental information on immiscible displacement of fluids in porous media and suggest the potential to improve the displacement efficiency of scCO2 by using surfactants.

A Study on the Cooperation between Medical Care and Law - Focusing on the discussion of the role of clinical practice guideline in Japan - (의료와 사법(司法)의 협력 -일본에서의 진료가이드라인의 역할에 대한 논의를 중심으로-)

  • Song, young-min
    • The Korean Society of Law and Medicine
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    • v.23 no.2
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    • pp.39-65
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    • 2022
  • There are two aspects of clinical practice guidelines that act as non-legal control before medical practice and as legal control standards after medical practice. The essential purpose of clinical practice guidelines is the former, but the latter action cannot be excluded. The clinical practice guidelines are a means of linking law and medical care. The negative perception of clinical practice guidelines that medical professionals' autonomy can be violated by the enactment of clinical practice guidelines is an excessive negative evaluation of clinical practice guidelines. Rather, judicial judgment based on clinical practice guidelines plays a role in respecting the autonomy of medical professionals. In other words, the clinical practice guidelines suppress legal regulations on medical care as much as possible and are based on doctors' professional ethics and self-discipline, and patient awareness and cooperation. In order to establish an ideal relationship of cooperation between doctors and patients, 'medical ethics' must be incorporated as a legal means. Clinical practice guidelines are the most appropriate means for incorporating such medical ethics into legal procedures. The lawyer solves the case with a legal syllogism that establishes a norm and applies facts to it to conclude. For the resolution of medical disputes, Clinical practice guidelines are used to establish norms that doctors should perform for specific diseases, and conclusions are drawn by applying the established norms to specific medical practices. When it is not easy to apply the established norms to specific medical practices, medical judgments by experts, such as emotions, expert testimony, and explanations by expert members, are used. As such, the Law respects the autonomy of medical care even in the establishment of norms and the application of norms. In particular, Clinical practice guidelines prepared independently by the medical community are referred to in establishing norms, which are the prerequisites for legal syllogism. This shows that doctors participate in the formation of precedents and contribute to the formation of norms. The use of clinical practice guidelines in trials is respect and consideration for the autonomy of medical care. Although there may be an aspect in which the autonomy of individual doctors is limited by clinical practice guidelines, it should be considered that the autonomy of doctors as a group is respected. In this way, the clinical practice guidelines play a role in protecting the autonomy of the "medical" group from the logic of the "law."

Synthesis of Zeolite P1 and Analcime from Sewage Sludge Incinerator Fly Ash (하수슬러지 소각 비산재를 이용한 제올라이트 P1 및 Analcime의 합성)

  • Lee, Je-Seung;Chung, Sook-Nye;Park, Chul-Hwi
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.6
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    • pp.659-665
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    • 2008
  • This study is about zeolite synthesis from the sewage sludge incinerator fly ash of "S" sewage treatment center located in Seoul. For this purpose, the properties of raw fly ash as starting material, the hydrothermal conditions for zeolite synthesis and the environmental applicabilities of synthesized zeolites were examined. Fly ash from sewage sludge incinerator has large quantities of SiO$_2$ and Al$_2$O$_3$ and their contents are 42.8 wt.% and 21.2 wt.% respectively. So fly ash is considered to be possible starting material for zeolite synthesis. The results from leaching test of fly ash showed that the concentration of hazardous metals were very low as compared with the Korea leaching standard of the Waste Management Law. But the concentration from total recoverable test of fly ash were higher than the fertilizer standard of Fertilizer Management Law. Major zeolite products synthesized by hydrothermal reaction are analcime in teflon vessel and zeolite P1 in borosilicate flask. Optimum conditions for the synthesis of analcime were 1 N of NaOH concentration, 16 hour of reaction time and 135$^{\circ}C$ of reaction temperature. For the zeolite P1 formation, the proper conditions were demonstrated to be 5 N of NaOH concentration, 16 hour reaction time and 130$^{\circ}C$ of reaction temperature in this study. Hazardous metal contents in the analcime product are similar with those in raw fly ash. In case of the zeolite P1, the contents are reduced to nearly a half. Raw fly ash and the analcime product showed NH$_4{^+}$ ion exchange capacity of 0$\sim$1.0 mg of NH$_4{^+}$g$^{-1}$ and 3.0$\sim$7.4 mg of NH$_4{^+}$g$^{-1}$, respectively. However, the zeolite P1 product reached exchange capacity to 14.6$\sim$17.8 mg of NH$_4{^+}$g$^{-1}$. This values are in the range of those of natural clinoptilolite and phillipsite. From this point of view, zeolite synthesis from sewage treatment sludge incinerator fly ash is a good alternative for solid waste recycling.

Characteristics of Natural Pedo-geochemical Background for Ni, Cu and Zn in Volcanic Soils of Jeju (제주도 화산회토양에서 Ni, Cu 및 Zn의 자연함유량 특성)

  • Lim, Han-Cheol;Moon, Kyung-Hwan;Jeon, Seung-Jong;Chang, Kong-Man;Hyun, Hae-Nam
    • Korean Journal of Soil Science and Fertilizer
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    • v.41 no.3
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    • pp.199-205
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    • 2008
  • This study was carried out to find out causes of high Ni content and characteristics of potential increase of Cu and Zn contents in the soils of Jeju area. Soil samples were collected from 4 series of Alfisols, 35 series of Andisols, 9 series of Entisols, 16 series of Inceptisols, and 1 series of Ultisols, respectively. Parent material (gravel) samples were also collected from the same sites where soil samples were taken. Both soil and parent material samples were analyzed for Ni, Cu, and Zn. The average Ni content of all the soil samples was $79.2mg\;kg^{-1}$, which was exceeded warning standard for Ni against the Soil Conservation Act in Korea, whereas that of Cu and Zn contents were lower than the warning standard for Cu and Zn. The difference of Ni, Cu and Zn content was not consistent depending upon soil color. Ni content in the soil samples from Entisols was particularly high, whereas that from the other soil orders was similar to each other. Cu and Zn contents in the soil samples were similar regardless of the difference in soil order. Ni content in Seongsan Formation(SSF), Cinder cone(C) and acicular Feldspar Olivine Basalt(FOB) was high, while that in Feldspar Basalt(FB) and Trachy Andesite lava(TA) was low. Ni content in the non-agricultural land was higher compared with that in the agricultural land, whereas Cu and Zn contents in the non-agricultural land were significantly lower than that of agricultural land. The topsoil/subsoil ratios for Ni content in most of the soil samples were less than 1, while that for total contents of Cu and Zn in many of the soil samples were larger than 1 indicating potential Cu and Zn accumulation in topsoil by artificial reasons.

A Study on the Working Environment Recognition and the Caracter Disposition of Nurse Aides (간호조무사의 근무환경인식과 성격성향에 관한 연구)

  • Lee Sun Yi
    • Journal of Korean Public Health Nursing
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    • v.4 no.1
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    • pp.57-74
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    • 1990
  • As the whole world took on the tendency to be highly industrialized, it became necessary for each field of occupation to require professional man power. Especially, since the World War n, the participation of woman power in economic activities has been continually increasing. In our country also, because of the rapid economic growth, change in the way of thinking of women as well as their participation in economic activities are increasing. Thus, woman power is being utilized in various occupational fields from simple physical labor to those that require high-professional skill. Also, continued economic development policies, by setting the establishment of welfare society as the ideology to be fulfilled, brought expansion of medical facilities in the field of public health and increase in man power in that field. As for the nursing specialists, more than 6000 have been being produced per year and as of the end of 1988, the total number of nursing specialists, reached 123, 115. Therefore, this study is done to recognize the professional knowledge and ability of nursing specialists, who take up $40\%$ of the total public-health related man power in our country, through evaluating their working environment and their disposition of character. This study, which was done from September 18th to September 30th 1989, took on the method of using formed questionnaires that had been amended and supplemented during two preparatory investigations, 322 of such questionnaires were used as an analytical material. In the formation of questionnaires, 12 questions were related to the working environment, and 26 in fortotal were related to the disposition of character, 5 for wise-disposition, 11 for activedisposition and 10 for open-disposition. The measuring method, which used 5-point-standard, allowed 5 points for affirmative recognition of the working environment, also 5 points for showing wise, active and open disposition of character and only point in opposite cases. Collected materials were analyzed, through an electronic calculation, into the average value, the standard deflection percentage, pearson corelative number and stepwise multiple regression. Summarizing the results from this study is as follows: 1. It was shown that the nursing specialists with the average of 3.07 have affirmative recognition of their working environment. The questions which drew most affirmative reaction were those concerning finance-management system such as hand, the questions that received negative reaction were those concerning communication method with the average of 2.49. Such reaction seems to have resulted from the cramming regulation by the superior authorities. Concerning the recognition of working environment in relation to employment conditions, more affirmative recognition is shown with the average of 3.14. at hospitals where injection job is not performed. The nursing specialists working at regular hospitals show more affirmative recognition than those at general hospitals, the averages being respectiely 3.16 and 3.03. 2. As for the disposition of character of the nursing specialists, active-disposition was highest with the average of 3.38, next was wise-disposition with 3.20 and the lowest was open-diposition with 2.98. Variable-wise disposition of character shows that wise-disposition and academic background are beneficially correlated by 0.12. Ative-disposition and open-disposition show correlation to the office term by respectively 0.16 and 0.21. In other words. better academic background leads to higher wise-disposition and more - experience results in higher active and open disposition. Also, the class that performs the injection job, in relation to the working environment, might cause change in the self-conceit that identify those in that class with the nurses; however, as far as professional judgment and action, in dealing with nursing job, being wise, active and open is concerned, not much effect is made. 3. The relation between the recognition of the working environment and the disposition of character is that more afirmative recognition- a nursing specialist has about her working environment, the higher the active-disposition becomes by 0.13. The degrees of the relation between recongnition of environment and wise and open dispositions show respectively 0.06 and -0.06 and -0.06. That is to say that when having more affirmative recognition of the working environment, a nursing specialist shows wise but closed disposition of character. This, howerver, didn't mean much statistically. When observing the results mentioned above, it is conspicuous that the nursing specialists, working as substitutes for the nurse at medical institutions of various sizes, get the feeling of being somewhat equal to the nurses and to some extent, fulfill their desire to accomplish their ego; however, as far as professional ability expansion if concerned. they lack wise and open dispositions. Therefore, considiering upon the results of this study, in medical institutions where the work of nursing specialists is regaded equal to that of the nurses, as a medical member who deals with human lives, it is desirable to make the nursing specialists work under the supervision of the nurses and to offer them continuous education to strengthen and improve their natural dispositions.

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A Study on the Tree Surgery Problem and Protection Measures in Monumental Old Trees (천연기념물 노거수 외과수술 문제점 및 보존 관리방안에 관한 연구)

  • Jung, Jong Soo
    • Korean Journal of Heritage: History & Science
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    • v.42 no.1
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    • pp.122-142
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    • 2009
  • This study explored all domestic and international theories for maintenance and health enhancement of an old and big tree, and carried out the anatomical survey of the operation part of the tree toward he current status of domestic surgery and the perception survey of an expert group, and drew out following conclusion through the process of suggesting its reform plan. First, as a result of analyzing the correlation of the 67 subject trees with their ages, growth status. surroundings, it revealed that they were closely related to positional characteristic, damage size, whereas were little related to materials by fillers. Second, the size of the affected part was the most frequent at the bough sheared part under $0.09m^2$, and the hollow size by position(part) was the biggest at 'root + stem' starting from the behind of the main root and stem As a result of analyzing the correlation, the same result was elicited at the group with low correlation. Third, the problem was serious in charging the fillers (especially urethane) in the big hollow or exposed root produced at the behind of the root and stem part, or surface-processing it. The benefit by charging the hollow part was analyzed as not so much. Fourth, the surface-processing of fillers currently used (artificial bark) is mainly 'epoxy+woven fabric+cork', but it is not flexible, so it has brought forth problems of frequent cracks and cracked surface at the joint part with the treetextured part. Fifth, the correlation with the external status of the operated part was very high with the closeness, surface condition, formation of adhesive tissue and internal survey result. Sixth, the most influential thing on flushing by the wrong management of an old and big tree was banking, and a wrong pruning was the source of the ground part damage. In pruning a small bough can easily recover itself from its damage as its formation of adhesive tissue when it is cut by a standard method. Seventh, the parameters affecting the times of related business handling of an old and big tree are 'the need of the conscious reform of the manager and related business'. Eighth, a reform plan in an institutional aspect can include the arrangement of the law and organization of the old and big tree management and preservation at an institutional aspect. This study for preparing a reform plan through the status survey of the designated old and big tree, has a limit inducing a reform plan based on the status survey through individual research, and a weak point suggesting grounds by any statistical data. This can be complemented by subsequent studies.

A Study about the Aesthetics of Oriental in Modern Fashion design (현대패션디자인에 나타난 동양의 미의식 연구)

  • 임영자
    • Journal of the Korean Society of Costume
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    • v.30
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    • pp.261-274
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    • 1996
  • In the present age dominate by both cer-taingty of 1% and uncertainty of 99% 'Fuzzy thinking' of Bart Kosko that is the way to solve the problems by the scientific way through a worldview of Buddhism or Taoism greatly prevails around the world over 'Lateral greatly prevails around the world over 'Lateral thinking' and the authenticity or the right and-wrong of the uncertainty which is the thinking way to find the answer of the problems of illogical way of Edward de Beno against the western vertical thinking were Concurrently fashion designers over the world also adopt the oriental elements. But there exist differences of thoughts between the orient and the occident. And they have dif-ferent thinking way of aestheticism and references of the value on the beauty. Not only beauty but the view through the mind as intuitional thought in which not only the rec-ognition of sense but also the rationalism and the naturalness play key role. The aesthetic sense in the orient contains both the truth and virtue. 2) The beauty of the mean It's from the thought of neutralization of Confucius. The mean or moderation state which in harmony with ethical virtue and aes-thetic beauty is the ideal and is the ultimate. Therefore the thought of Confucian is the creativity in which the balance and the har-mony is most important. Fashion design is also one of the representation of the mean because the spirit of the designer is harmonized for-mlessly with the object of the model of the fashion design. 2) The beauty of skillfulness It indicates the Taoism of Lao-tzu and Chuangtzu. It takes a super-artistic declar-ation that human can feel and recognize the color of colorlessness the sound of sound-lessness and the taste of tastelessness. The thought of arts affected by Taoism is 'ad-vanced age' called the beauty of skillfulness. The view of arts of lao-tzu takes the beauty of cosmos and the nature as a standard. Es-pecially the beauty of inactivity is recognized by the linkage between the beauty and the ugliness. And these things appear in fashion design as a design element such as humor or exaggeration. 3) The beauty of non-dualism It is thought of Buddhism that all evil passions of worry occur form the opposition in dualism. Finally this thought leads to that everything is consistent and truth is only one from the point of view that virtue and vice has on linkage that is 'no virtues no vices' and 'one with two, two, with one, one is not two' A big tendency like this became the root forma-tion of the thought of the oriental arts. 3. Characteristics of the oriental aesthetic sense on the present fashion design 1) The formation of the fashion design on the oriental elements In the picture-incantation which was a representation of an era when the thought of 'cosmic dual forces' dominated the basic polygons of 'a circle square triangle' means both 'one two three' and 'the negative positive mean' of cosmic elements. From this point of view the was of planner cutting in the Orient is dif-ferent from that of the Occidental which is in three-dimensional. The planner polygon type of the cut-pieces comes to have the meaning of the three-dimension when they consist of a suit that has the combination of each cut-piece. This shows the consistency with the principle of cosmos creation of Taoism that one is two two is three and three is every-thing. 2) The coloring and the symbolic represen-tation of the fashion design on the orien-tal elements The sense on the colors in the Orient from the thought of 'the cosmic dual forces and the five elements' is not the experi-enced from the knowledge but contains the consideration of philosophy Five-primary-color representing compass directions Blue(East) Red(South) Yellow(Center) White (West) and Black (North) is called ' the posi-tive' for this five-primary-color secondary-color which comes from the compound of the primary colors is called 'the negative' The thought of 'the cosmic dual forces and the five elements' is also an theory containing the natural order of the cos-mos and this shows the perceptional differ-ence that they are not conceptual but to be recognized and fell directly. A thought of Buddhism which is 'Colors are colorlessness and Clolorlessness are color's proves that. 3) The pattern and symbolic representation of the fashion design on the oriental elements The pattern as a visual style is a figure of symbolic representation which adopt the mental and physical world of human and are the compo-sition of artistic revelation of the human nature and the religous thought of incantation. Es-pecially the symbolic representation of the oriental thought of Confusion. Buddhism and Taoism There are patterns such as plants aminals the oriental four gods and geometry. From the above it's the time toward the 21'th century when the world is constructing one global area and one historical zone. And the exotic mood of the Orient represented in the fashion which doesn't make the common feeling in general does not cease to develop only to express the visual modeling but also adopts the thought religion and the art which are the root of the Orientail and contains inherent willing of modeling.

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DEVELOPMENT OF BIOCOMPATIBLE DRESSING MATERIAL MADE OF COLLAGEN AND AMNIOTIC MEMBRANE AND WOUND HEALING EXPERIMENT IN RAT (양막과 콜라겐을 이용한 생체 적합 드레싱 소재 개발 및 백서 창상치유 실험)

  • Ahn, Kang-Min;Lee, Ji-Ho;Lee, Ui-Lyong;Lee, Jong-Ho;Lee, Jong-Won;Kim, Sung-Po;Yang, Eun-Kyung;Kim, Ki-Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.32 no.3
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    • pp.189-199
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    • 2006
  • Purpose of study: Partial thickness skin graft is the golden standard regimen for full-thickness skin defect caused by burn or trauma. However, in case of extensive burns of more than 50% of total body surface area, the donor site is not sufficient to cover all defects. As a second choice, allograft, xenograft and synthetic materials have been used to treat skin defect. Among them the amniotic membrane(AM) was used as a biological dressing for centuries because of its potential for wound healing. In this study, quantification of EGF in AM and effect of AM-collagen complex on full thickness skin defects was examined. Materials & Methods: The concentration of EGF in fresh, deep frozen and freeze-dried AM was evaluated by ELISA. EGF-R immunostaining was performed in freeze-dried AM. SD rats weighing 250${\sim}$300g was used for wound healing experiment. Three full thickness skin defects(28mm diameter) were made on dorsal surface of SD rat. The control group was covered by Vaselin gauze and AM-collagen complex and $Terudermis^{(R)}$. was grafted in two other defects. Healing area, Cinamon's score were evaluated before biopsy. Grafted sites were retrieved at 3 days, 1 week, 2 weeks and 4 weeks after operation. H & E and Factor VIII immunohistochemical stain was performed to evaluate the microscopic adhesion and structural integrity and microvessel formation. Results: 1. EGF concentration of fresh, deep frozen and freeze-dried AM showed similar level and EGF-R was stained in epithelial layer of freeze-dried AM. 2. At 4 weeks after grafting, the healing area of AM-collagen and Terudermis group was 99.29${\pm}$0.71% and 99.19${\pm}$0.77 of original size. However, that of control group was 24.88${\pm}$2.90. 3. The Cinamon's score of AM-Collagen and $Terudermis^{(R)}$. group at 4 weeks was 15.6${\pm}$1.26 and 14.6${\pm}$3.13 and that of control group was 3.7${\pm}$0.95. Significant difference was observed among control and experimental groups(p<0.05). 4. Histologic examination revealed that AM protected leukocyte infiltration and epithelial migration was nearly completed at 4 weeks. $Terudermis^{(R)}$. group showed mild neutrophil infiltration until 2 weeks and completion of epithelization at 4 weeks. Control group showed massive leukocyte infiltration until 4 weeks. 5. Microvessels were increased sharply at 1 week and control group at 1 and 4 week showed significant differences with $Terudermis^{(R)}$. group of same interval(p<0.05) but no differences were found with AM group(p<0.05). Conclusion: EGF and EGF-R were well preserved in freeze-dried AM. AM attached to collagen acted as excellent biologic dressing which had similar effect with $Terudermis^{(R)}$. AM showed anti-inflammatory action and healing was completed at 4 weeks after full-thickness skin defect.

EVALUATION OF OSTEOGENIC ACTIVITY AND MINERALIZATION OF CULTURED HUMAN PERIOSTEAL-DERIVED CELLS (배양된 인간 골막기원세포의 조골활성 및 골기질 형성의 평가)

  • Park, Bong-Wook;Byun, June-Ho;Lee, Sung-Gyoon;Hah, Young-Sool;Kim, Deok-Ryong;Cho, Yeong-Cheol;Sung, Iel-Yong;Kim, Jong-Ryoul
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.28 no.6
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    • pp.511-519
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    • 2006
  • Autogenous bone grafts have been considered the gold standard for maxillofacial bony defects. However, this procedure could entail a complicated surgical procedure as well as potential donor site morbidity. Possibly the best solution for bone-defect regeneration is a tissue engineering approach, i.e. the use of a combination of a suitable scaffold with osteogenic cells. A major source of osteogenic cells is the bone marrow. Bone marrow-derived mesenchymal stem cells are multipotent and have the ability to differentiate into osteoblastic, chondrocytic, and adipocytic lineage cells. However, the isolation of cells from bone marrow has someproblems when used in clinical setting. Bone marrow aspiration is sometimes potentially more invasive and painful procedure and carries of a risk of morbidity and infection. A minimally invasive, easily accessible alternative would be cells derived from periosteum. The periosteum also contains multipotent cells that have the potential to differentiate into osteoblasts and chondrocytes. In the present study, we evaluated the osteogenic activity and mineralization of cultured human periosteal-derived cells. Periosteal explants were harvested from mandibule during surgical extraction of lower impacted third molar. The periosteal cells were cultured in the osteogenic inductive medium consisting of DMEM supplemented with 10% fetal calf serum, 50g/ml L-ascorbic acid 2-phosphate, 10 nmol dexamethasone and 10 mM -glycerophosphate for 42 days. Periosteal-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 14 of culture period, then decreased in intensity during the culture period. ALP mRNA expression increased up to day 14 with a decrease thereafter. Osteocalcin mRNA expression appeared at day 7 in culture, after that its expression continuously increased in a time-dependent manner up to the entire duration of culture. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. In conclusion, our study showed that cultured human periosteal-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix. As the periosteal-derived cells, easily harvested from intraoral procedure such as surgical extraction of impacted third molar, has the excellent potential of osteogenic capacity, tissue-engineered bone using periosteal-derived cells could be the best choice in reconstruction of maxillofacial bony defects.

Determination of Optimun Coagulant Dosage for Effective Water Treatment of Chinyang Lake -The Effect of Coagulant Dosing on Remoaval of Colloidal Pollutants- (진양호소수의 효과적인 정수처리를 위한 최적응집제 주입량 결정 -콜로이드성 오염물질 처리를 위한 응집제 주입효과-)

  • 이원규;조주식;이홍재;허종수
    • Journal of Environmental Science International
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    • v.7 no.6
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    • pp.761-772
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    • 1998
  • This study was performed to determine the optimum coagulant dosing amount for effective treatment of raw water. The removal rate of turbidity and the variations of water qualities according to various dosage of coagulants such as Alum, PAC and PACS were investigated. The optimum coagulant dosing amount to make the lowest turbidity of water were 35mg/ι t of Alum, 30mg/ι of PAC and 10mg/ι of PACS in case of 5 NTU of raw water turbidity, and 30mg/ι of Alum, 25mg/ι of PAC and 10mg/ι of PACS in case of 10 NTU of that, respectively. The removal rates of turbidity at 4 min. and 8 min. of settling time were 10 and 72% of Alum, 44 and 62% of PAC and 25 and 55% of PACS in case of 5 NTU, and 52 and 70% of Alum, 90 and 95% of PAC and 10 and 28% of PACS in case of 10 NTU, respectively. Judging from the settling capability of floc., the reaction time of floe. formation and removal efficiency of turbidity, PAC was evaluated as more effective coagulant than Alum and PACS. Also PAC was regarded as the most effective coagulant when the water supply was changed sharply and the fluctuation of the surface loading occured with wide and sharp in settling basin. pH and alkalinity of the water were decreased with increasing coagulants dosage. But pH and alkalinity were not decreased below 5.8 which is the standard for drinking water quality, and 10mg/ι which is the limit concentration of floc. breakage, respectively. Residual Al of the treated water was decreased with increasing coagulants dosage in case of 5 and 10NTU of raw water turbidity. $KMnO_4$ consumption of the water was decreased with increasing coagulants dosage. The reduction rate of $KMnO_4$ consumption at the optimum coagulants dosage were 39% of Alum. 18% of PAC and 11% of PACS in case of 5 NTU of raw water turbidity, and 42% of Alum, 27% of PAC and 36% of PACS in case of 10 NTU of that, respectively. Any relationship was not found between the removal rate of turbidity and KMnO$_4$ consumption. TOC of the water was a bit decreased with increasing coagulants dosage up to 30mg/ι but not changed above 30mg/ι of coagulants dosage. The degree of TOC reduction was increased in the order of Alum, PAC and PACS treatment. Zeta potential of the colloidal floe. at the optimum coagulants dosage was in the range of -20~-15mV in case of 5 NTU of raw water turbidity and 0~0.5mV in case of 10 NTU of that. respectively. Although the kinds and dosages of coagulants were different, zeta potential range were fixed under the conditions of the best coagulation efficiency.

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