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Effect of Synagis (palivizumab) prophylaxis on readmission due to respiratory syncytial virus in very low birth weight infants (극소 저체중 출생아에서 Synagis (palivizumab) 접종이 respiratory syncytial virus 감염으로 인한 재입원에 미치는 영향)

  • Park, Soo Kyoung;Jung, Yu Jin;Yoo, Hye Soo;Ahn, So Yoon;Seo, Hyun Joo;Choi, Seo Hui;Kim, Myo Jing;Jeon, Ga Won;Koo, Soo Hyun;Lee, Kyung-Hoon;Chang, Yun Sil;Park, Won Soon
    • Clinical and Experimental Pediatrics
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    • v.53 no.3
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    • pp.358-364
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    • 2010
  • Purpose : The aim of this study was to determine the efficacy of $Synagis^{(R)}$ (palivizumab) in reducing the respiratory syncytial virus (RSV) readmission rate in very low birth weight infants (VLBWI ) and the subgroup that showed the most effective vaccination. Methods : We enrolled 350 VLBWI who had been discharged alive from the neonatal intensive care unit of Samsung Medical Center from January 2005 to December 2007 and were followed up for at least one year. A retrospective study based on medical records was performed for a period of one year after discharge. RSV readmission rate was investigated according to BPD (bronchopulmonary dysplasia, requiring oxygen at postnatal day 28) and $Synagis^{(R)}$ prophylaxis. We categorized the subgroups by the severity of BPD gestational age, and birth weight and compared the RSV readmission rates between subgroups. Results : Eleven VLBWI were readmitted. $Synagis^{(R)}$ prophylaxis resulted in a 86% reduction in the rate of readmission due to RSV infection (prophylaxis group, 0.7% and no prophylaxis group, 5.0%; P =0.02). Readmission rate in BPD patients was also reduced in the prophylaxis group (0.7% in the prophylaxis group vs. 5.2% in the no prophylaxis group, P =0.03). The readmission rate in patients without BPD was reduced in the prophylaxis group (0% in the prophylaxis group vs. 4.9% in the no prophylaxis group, P =1.00), but this was not statistically significant.Conclusion : $Synagis^{(R)}$ prophylaxis was effective at reducing RSV readmission in VLBWI. Its efficacy was verified irrespective of BPD, gestational age, or birth weight.

Analysis on the Shear Behavior of Existing Reinforced Concrete Beam-Column Structures Infilled with U-Type Precast Wall Panel (U형 프리캐스트 콘크리트 벽패널로 채운 기존 철근 콘크리트 보-기둥 구조물의 전단 거동 분석)

  • Ha, Soo-Kyoung;Son, Guk-Won;Yu, Sung-Yong;Ju, Ho-Seong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.6
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    • pp.18-28
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    • 2015
  • The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of U-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D, agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

A Study on the Imitation and Transformation of Gugok-Wonlim Culture through Management of the Myungam Jeong Sik's Muyi-Gugok in Sancheong (명암(明庵) 정식(鄭拭)의 산청 무이구곡(武夷九曲) 원림경영을 통해 본 구곡문화의 모방과 변용)

  • Rho, Jae-Hyun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.33 no.3
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    • pp.84-94
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    • 2015
  • This study is to examine how the admiration for Chutzu(朱子)'s achievement while he was preaching his policies after renouncing the world in Wuyi-Gugok(武夷九曲), Mt. Wuyi and Joseon-style transformation culture were unfolded and developed through Gugok management cases such as position, name, poetic diction, Jungsa(精舍) architecture and engraving of Muyi-Gugok set in Mt. Gugok, Snacheong. The results were as follows: Myungam(明庵) Jeong Sik(鄭拭, 1683~1746)'s Muyi-Gugok, which consists of Suhongkyo(垂虹橋, gok 1) - Oknyeobong(玉女峰) - Nhongwhaldam(弄月潭) - Nacwhadam(落花潭) - Daeeunbyeong(大隱屛) - Gwangpyungryea(光風瀨) - Jaewhaldae(霽月臺) - Gorooam(鼓樓巖) - Wharyongpok(臥龍瀑, gok 9) is the representative case where Chutzu's Wuyi-Gugok was exactly copied and fulfilled to the Joseon Dynasty. In a large frame, Gugok Wonlim culture, Myungam's Muyi-Gugok management has a will of succession of Dotong(道統) through admiration for Chutzu in a rigid way. Another name of Mt. Gugok is Mt. Muyi and Gugok's name is Muyi-Gugok and the residence existed between gok 4 and gok 5. In addition, the name of Jeongsa for Gugok management is also 'Muyi Jeongsa(武夷精舍)' and Gugok name and contents of Poetry are also similar and all of these are clear evidence that Myungam tries to copy Chutzu's Wuyi-Gugok to Mt. Gugok. Also, Gugok set before Myungam were located in Mt. Gugok and among them, verified four Gugok names are corresponded to those of Chutzu's Wuyi-Gugok and it tells that conforming behavior as one of admiration ways for Chutzu already arrived at Mt. Gugok before Myungam and this was an oppotunty to widen Mt. Gugok Muyi-Gugok's tradition and horizon. Also, considering that Myungam's gok 6, Gwangpyungryea and gok 7, Jewoldae are names from 'Gwangpungjewol(光風霽月)' Based on Chutzu's poem and they are closely related to Joseon's classical scholar spirit, they are associated with Joseon-style transformation of Chutzu's Muyi-Gugok. Meanwhile, gok 5 'Daeeunbyeong' was transformed to 'Nangaam(爛柯巖)' in gok 5 - "Deoksan-Gugok(德山九曲) of Jooko(竹塢) Ha Beom-Woon(河範運, 1792~1858) and those characters's engravings are handed down. In "Pome of Deoksan Gugok" transformed from Myungam's Muyi-Gugok, respect and admiration for Chutzu is weaken while Ha Beom-Woon admires Nammyeong(南冥) Cho shik(曺植, 1501~1572), a symbolic character of himself's school and from this, a movement to promote partisan unity is identified. After Myungam died, Muyi-Gugok in Mt. Gugok was transformed from a space to succeed Chutzu's Dotonga to one to commemorate the memory of ancient sages, but, it is a typicality case that widen the spectrum of Joseon's Gugok-Wonlim culture through Muyi-Gugok's imitation and transformation.

A Study on the Origin and Transformation of Jeonju-Palkyung (전주팔경의 시원(始原)과 변용(變容)에 관한 연구)

  • Rho, Jae-Hyun;Son, Hee-Kyung;Shin, Sang-Sup;Choi, Jong-Hee
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.33 no.3
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    • pp.1-15
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    • 2015
  • Based on the analysis and interpretation of the headwords and poetic words of a group of eleven collecting sceneries of Jeonju, the origin and transformations of the Jeonju-Palkyung(Eight sceneries of Jeonju) investigated by a time-series analysis are as follows. As there is no collection of landscape with a formal structure similar to that of the current Jeonju-Palkyung, prior to the Palkyung by Chujae(秋齋) Cho Soo-Sam(趙秀三, 1762~1849), there is no significant problem in assuming the eight poems in Chujaejib(秋齋集) are the origins of the Jeonju-Palkyung, and it is estimated to have been produced in 1829. In the late-19th century poem 'Wansanseunggyeong(完山勝景)', 'the Palkyung in Yeollyeo Chunhyang Sujeolga', and 'the Palkyung delivered by poet Shin Seokjeong in the Japanese colonial era', only the 'Dongpogwibeom(東浦歸帆)' changed from Dongjipo to Dongchon of Bongdong as for 'Landscape Setting There($L_{ST}$)' according to changes in district administration; despite this change, the fact that they are not too different from the Palkyung of Cho Soo-Sam, also supports this. Moreover, according to the headword concordance analysis, it is proven that the Jeonju-Palkyung was established in the late-19th century and continued to be the region's representative sceneries even during the Japanese colonial era, and later 'Namcheonpyomo(南川漂母)' and 'Gonjimangwol(坤止望月)' were added to expand to the Jeonju-Sipkyung(ten sceneries of Jeonju). But when we see there are famous spots that are the origins of the Jeonju-Sipkyung, including Gyeonggijeon, Geonjisan, Jogyeongdan, Omokdae, and Girinbong, Deokjinyeon, and Mangyeongdae, all of which have great representational significance as the capital of Jeolla Provincial Office as well as of the place of origin for Joseon Dynasty in the grouping of sceneries during the early Joseon Dynasty, including "Paehyangsipyeong (沛鄕十詠)", "Gyeondosipyeong (甄都十詠)", and "Binilheonsipyeong(賓日軒十詠)", the beginnings of the semantic Jeonju-Palkyung should be considered up to the first half of Joseon Dynasty. During this period, not only the fine sceneries with high retrospective merit as the capital of Hubaekje, like Gyeonhwondo(甄萱都), but also the sceneries like Mangyeongdae that reminds people of Jeong Mongju(鄭夢周) and Yi Seonggye(李成桂) in the late period of Goryeo appeared, elevating the status of Jeonju as the capital of Hubaekje and shortening the historical gaps as the place of origin of the Joseon Dynasty. The Jeonju-Palkyung is an organic item that carries the history of the Joseon Dynasty after Hubaekje and has gone through many cycles of disappearing and reappearing, but it has continued to change and transform as the region's representative sceneries. The Jeonju-Palkyung is a cultural genealogy that helps one understand the 'Jeonju Hanpunggyeong(韓風景: the sceneries of Korea in Jeonju)', and the efforts to preserve and pass it down to the next generation would be the responsibility of the people of Jeonju.

A Basic Study on Spatial Configuration of Gang-jin Nongsanbyeoleop (강진 농산별업(農山別業)의 공간구성에 대한 기초 연구)

  • Seo, Dong-Il;Lee, Jae-Keun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.2
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    • pp.64-71
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    • 2012
  • This is a basic study for recovering original form of Nongsanbyeoleop(農山別業) in Gangjin, Jeonnam, created in the latter part of Joseon period and the estimation of originla form at the time of creation was conducted by analyzing related literature and inspecting the actual site. "Joseokruki(朝夕樓記)" of Dasan Jung, Yak Yong could estimate spatial structure and using form of Nongsanbyeoleop and the arrangement of spatial structure in literature could be confirm by on-the-site inspection. The results of this study are as follows. The first, Nongsanbyeoleop managed spatial factors applying natural topography. For the spatial characteristics of Nongsanbyeoleop, the location of ancestral ritual space including deceased father's tomb and tomb house far from the main levee of Yun, Kwang Taek, a father of Yun, Seo Yu by 1.9km and housekeeping could be confirmed. The second, spatial estimation by "Joseokruki" could be possible. "Joseokruki" describes Joseokru.Youngmojae.Hanokkwan.Cheokyunjung.Sangam as construction factors, Wundang.Kookdan.Nokwunoh. as plant factors, Sookyunggan.Keumkoji.Nokeumjung.Uijanghae as hydroponic factors and Pyoeunkok.Aengjakang as natural topography factors. However, most of them were disappeared and at present, only Youngmojae, Keumgoji, Kukdan and Wundang show the past trace. The third is for the changed space of Nongsanbyeoleop and its reason. The surrounding space of Nongsanbyeoleop was planated by land arrangement in 1960s and it played a role of topographical damage because it's recognized as the plane factor including Nongsanbyeoleop's surrounding landscape rather than dotted factor. The forth, the actual measurement of Nongsanbyeoleop and digitalization of manual map of numerical value are judged to be sufficient to apply as the basic material for recovering garden in the future. Because of the diatahce changing method applied at that time, the garden recovery of Nongsanbyeoleop intended to be concreted and 3D model established by digitalized basic materials is considered to apply for multilateral studying. Thus, Nongsanbyeoleop which is byeolseo including the tomb of deceased father based on the conceptual hyo thought shows clear differences from the organized factors of Byolseowonrim of precedent studies and the importance of Byolseowonrim is sufficient. But, the constructional factors which cannot know disappeared spatial factors and accurate location became the limitation of this study. In the future, clear verification of original form must be progressed by excavation which can confirm the location of construction factors.

A Study on the Landscape Structure and Meaning of Eight Scenic Views of Yeongsa-jeong Pavilion through the Painting and Poem (<영사정팔경도(永思亭八景圖)>와 팔영시로 본 영사정팔경의 경관구조와 의미)

  • Rho, Jae-Hyun;Son, Hee-Kyung;Kim, Hong-Kyun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.35 no.2
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    • pp.58-68
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    • 2017
  • The conclusion of this research after analyzing and interpreting the landscape structure and meaning of Yeongsajeongpalkyung (永思亭八景) that appears in Yeongsajeongpalyeongsi(永思亭八詠詩) of Cheonggye(靑溪) Yang, Dae-bak(梁大樸, 1544~1592) and through document studies, poetry and painting analysis and interpretation, and site investigation, is as follows. Yeongsajeong and its nearby lands are the area of "Yeongsa", where the builder, Ahn, Jeon(安?, 1518~1571) worshipped towards the grave of ancestors, and Yeongsajeongpalkyung oversees a family burial ground in Namwon, centering around Yeongsajeong such as Yocheon, Geumseokgyo and Cheonggyedong, and Sunjagang River and Mountain Jiri, which are the foot hold and key points of advantageous scenic views in Namwon. Yeongsajeongpalkyung, unlike general Jeongjapalkyung, shows a panoramic bird's-eye structure overseeing the landscape and scenery of the Yocheon area and Sunjagang River, in addition to Yeongsajeong, while show in a transition of location, a multi-view structure and time. The trace of visual unity with Sosangpalkyung of China can be seen in many places in Yeongsajeongpalkyung, which seems to be a transitional feature of composing poems regarding Palgyeong during the mid-Joseon dynasty, which pursues harmony with the local landscape of the Namwon area. The 'Changsongchwijuk(蒼松翠竹)' appearing in each of the first and second scenic views of Palgyeong and Yeongsajeongpalyeong can be understood as an incarnation of Yang, Dae-bak, the author of Palyeongsi or Ahn, Jeon, the builder of Yeongsajeong. On the other hand, as a result of interpreting the yin-yang features of poetic diction and picture elements appearing in the subtitle of Yeongsajeongpalyeong, Palyeongsi seems mostly full of yin-like elements and Palgyeongdo. Moreover, as a result of comparing and analyzing the acts expressed in and acts described in Yeongsajeongpalyeong, based on the fact that the reis almost no common ground between the two media except for Soongangmowoo, the third scenic view, the formal similarity between the two media can be acknowledged, however, it is difficult to discover any substantive 'integrity of poetry and painting'.

A Study on the Present Condition of Four-Year University Curriculum for Introducing NCS Landscape Architecture (NCS 조경 분야 적용을 위한 4년제 대학 교육과정 현황분석)

  • Lee, Chang-Hun;Kim, Kyou-Sub;Lee, Won-Ho
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.37 no.3
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    • pp.134-147
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    • 2019
  • The purpose of this study was to analyze the functional unit system of NCS landscape field for correction and supplementation of NCS landscape field and the contents of the four-year college landscape course subject. First, 24 unconsolidated four-year universities were selected, and FGI was conducted and verified for 816 courses in 24 universities. The results of the study are summarized as follows, with three sections three, nine divisions and 65 sub-category. First, landscape design subjects accounted for 40.0% of the subjects organized by four-year universities. In addition, the ratio of 12.9% for ecological landscape, 11.3% for landscape construction, 10.2% for others, 10.0% for landscape information, 6.6% for landscape culture and 3.7% for landscape management was surveyed. Balanced and efficient modification and reinforcement of NCS is required in the future. Second, 10(18.9%) units with matching NCS performance criteria and educational objectives were found to be capable of different units(18.9%), 15(28.3%), and 37subjects with inconsistent NCS unit capability (56.9%). Third, looking at the criteria for the reference of each unit of capability presented by the NCS, it is deemed that one unit of capability should be organized separately to improve the practical ability, since it includes the contents of basic knowledge learning. Fourth, the objectives pursued on the basis of the contents of the NCS capability unit and four-year college curriculum were developed by focusing on the development of unit capabilities in the field of landscape construction and landscape management compared to the field of landscape design. It has been shown that a balance is needed for future development. This study is intended to put forward further research that re-examine specific curriculum assessment criteria that have not been classified in the course of classifications based on the curriculum handbook, which excludes interferences from each school.

A Study on the Relationship of Educational Subjects in Dasan's 『Dàxuégōngyì』 - piety(孝), admiration(弟), mercy(慈) - (다산(茶山) 『대학공의(大學公議)』에서 교육주체들의 관계 고찰 - 효(孝)·제(弟)·자(慈)를 중심으로 -)

  • Jo, Moon Sook
    • Korean Educational Research Journal
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    • v.40 no.2
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    • pp.17-33
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    • 2019
  • This study examines the fundamental ethics of practice that Dasan Jung Yak-yong(1762-1836) argued at the book, "Dàxuégōngyì大學公議, The Public debate of Great Learning", by investigating the relationship between main agents of education. "Dàxuégōngyì", the book that Dasan wrote when he was 53 years old at his exiled place, Gangjin. As the title suggested, Dàxuégōngyì, it could be recognized as the impartial view based on the critical perspective to Zhūxǐ(朱憙)'s opinion. Zhuxi focused on the importance of "Great Learning 大學" as a study of the Great people and argued that "Great Learning" is the study for all the people should learn. On the other hand, Dasan claimed that "Tàixuézhīdào太學之道" in "Great Learning" is the study for the prince, not for the normal people. And he also interpreted "Dàxué 大學" as the school for teaching prince. In addition, "Great Learning" suggested the three practical principles; to illustrate illustrious virtue; to renovate the people; and to rest in the highest excellence. However, Dasan argued different way and emphasized three ethics of practice; filial piety(孝), admiration(弟), mercy(慈) and regarded as illustrious virtue of "Great Learning." He denied the three principle of "Great Learning" that Zhuxi reorganized and suggested including renovating the people(新民), and provided that close to the people(親民) is one of the main principles of "Great Learning." According to Dasan, if the king practices these three ethics of practice including filial piety, admiration, and mercy, so that the people will practice these ethics voluntarily. In other words, he indicated that the practice of three ethics is not only for the prince in the loyal family, but also for principles to educate the people in the nation. Thus, three ethics by Dasan including filial piety, admiration, and mercy could be recognized as the symbol of humanity. In other words, Dasan's three ethics in "Great Learning" can be recognized as the practical principles including educational issues and educational interactions. If these three ethics can be referred as the symbol of humanity as mentioned above, the implicit educational interactions are specifically constructed within the basic assumptions. Therefore, it is possible to clarify the specific ethics of practice by the indicating specific subjects and objects in the educational interactions between these three ethics of practice. Also, it helps more clear comprehension about the "Dàxuégōngyì大學公議, The Public debate of Great Learning", by Dasan.

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Analysis of Building Energy Reduction Effect based on the Green Wall Planting Foundation Type Using a Simulation Program (건물일체형 패널형 벽면녹화 식재기반 유형별 건물에너지 성능 분석)

  • Kim, Jeong-Ho;Kwon, Ki-Uk;Yoon, Yong-Han
    • Korean Journal of Environment and Ecology
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    • v.29 no.6
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    • pp.936-946
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    • 2015
  • This study is aimed to analyze the reduction performance of building energy consumption according to planting base types of panel-type green walls which can be applied to existing buildings. The performance was compared to the general performance of green walls that have demonstrated effects of improving the thermal environment and reducing building energy consumption in urban areas. The number of planting base types was 4 in total, and simulations were conducted to analyze the thermal conductivity, thermal transmittance, and overall building energy consumption rate of each planting base type. The highest thermal conductivity by the planting base type was Case C (0.053W/mK), followed by Case B (0.1W/mK) and Case D (0.17W/mK). According to the results of energy simulation, the most significant reduction of cooling peak load per unit area was Case C (1.19%), followed by Case B (1.14%) and Case D (1.01%) when compared to Case A to which green wall was not applied; and the most significant reduction of heating peak load per unit area was estimated to be Case C (2.38%), followed by Case B (1.82%) and case D (1.50%) when compared to Case A. The amount of yearly cooling and heating energy use per unit area showed 3.04~3.22% of reduction rate. The amount of the 1st energy use showed 5,844 kWh/yr of decrease on average for other types when compared to Case A. The amount of yearly $CO_2$ emission showed 996kg of decrease on average when compared to Case A to which the green wall was not applied. According to the results of energy performance evaluation by planting location, the most efficient energy performance was eastward followed by westward, southward and northward. According to the results of energy performance evaluation by planting location by green wall ratio, it was found that as the ratio of green wall increased, the energy performance displayed better results, showing approx. double reduction rate in energy consumption at 100% of green wall ratio than the reduction rate at 20% to 80% of green wall ratio.

Assessment of dust exposure and personal protective equipment among dental technicians (치과기공사의 분진노출 수준 및 개인보호구 착용 실태 - 대구지역을 중심으로 -)

  • Park, Soo-Chul;Jeon, Man-Joong;SaKong, Joon
    • Journal of Technologic Dentistry
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    • v.33 no.1
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    • pp.93-102
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    • 2011
  • Purpose: The study aimed to evaluate working environment for dental technician by measuring dust level, ventilation conditions and the use of personal protective equipment and to provide basic information required to improve working environment and develop health education programs for dental technician. Methods: A total of 240 dental technician who are registered with the Daegu Association of Dental technician and working at 34 dental laboratories participated in the study. And the dust level was measured at 21 different spots in 16 dental laboratories out of 34. Results: Of 34 dental laboratories, 31 (91.2%) were equipped with a ventilator, but the remaining 3 (8.8%) did not have a ventilator. By the number of ventilator, 1 to 3 ventilators were found in 22 dental laboratories (71.0%), 4 to 6 ventilators were in 7 laboratories (22.5%) and more than 7 ventilators in 2 laboratories(6.5%). According to the frequence of changing filters in dust collector, 20 dental laboratories (58.9%) changed filters every four weeks, 10 laboratories (29.4%) changed them every six weeks and 4 laboratories (11.7%) changed them every eight weeks. Of total respondents, 114 (61.3%) said they wore a mask all the time while working, 56 (29.6%) said they frequently wore a mask, 19 (10.1%) said they did not wear a mask. As for the type of masks, 159 (84.1%) used a disposable mask, 25 (13.2%) used a cotton mask and 5 (2.7%) used an anti-dust mask. For dust sat on their outfits while working, 102 (54.0%) shook their uniforms inside workplace to keep dust off the uniforms, 64 (33.9%) did not anything until they wash their uniforms and 23 (12.1%) shook their uniforms outside workplace to keep dust off the uniforms. Of total respondents, 182 (96.3%) had a particle in their eyes while carrying out grinding work. Based on the measurement of floating dust at workplace, 3 dental laboratories showed dust concentration exceeding the minimum level of 10 mg/$m^3$ allowed under the permit for environment. Of those, 1 laboratory had the dust concentration that was more than 1.5 times higher than the minimum level. Dust concentration was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Dust comprised of nickel (more than 70%), chrome (9%) and others. The mean chrome concentration was more than twice higher than the minimum permissible level of 0.5 mg/$m^3$. There were two laboratories that showed chrome concentration exceeding the level of 0.4 mg/$m^3$. Like dust concentration, chrome level was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. There were six laboratories that had nickel concentration exceeding the minimum permissible level of 1 mg/$m^3$. Of those, one laboratory had nickel concentration that was more than three times higher than the minimum permissible level. Nickel concentration was also higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Conclusion: It is not likely that heavy metal concentrations found in the study constitute respiratory dust. It is however necessary for health of dental technician to apply the Industrial Safety and Healthy Law to dental laboratories and make recommendations for the use of personal protective equipment, installation of a proper number of ventilators, more frequent change of filters in dust collector and improved ventilation for polishing work. At the same time, dental technician need education on how to use personal protective equipment and how to efficiently remove dust from their uniforms.