• Title/Summary/Keyword: 상호영향관계도

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Swelling and Mechanical Property Change of Shale and Sandstone in Supercritical CO2 (초임계 CO2에 의한 셰일 및 사암의 물성변화 및 스웰링에 관한 연구)

  • Choi, Chae-Soon;Song, Jae-Joon
    • Tunnel and Underground Space
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    • v.22 no.4
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    • pp.266-275
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    • 2012
  • In this study, a method is devised to implement a supercritical $CO_2$ ($scCO_2$) injection environment on a laboratory scale and to investigate the effects of $scCO_2$ on the properties of rock specimens. Specimens of shale and sandstone normally constituting the cap rock and reservoir rock, respectively, were kept in a laboratory reactor chamber with $scCO_2$ for two weeks. From this stage, a chemical reaction between rock surface and the $scCO_2$ was induced. The effect of saline water was also investigated by comparing three conditions ($scCO_2$-rock, $scCO_2-H_2O$-rock and $scCO_2$-brine(1M)-rock). Finally, we checked the changes in the properties before and after the reaction by destructive and nondestructive testing procedures. The swelling of shale was a main concern in this case. The experimental results suggested that $scCO_2$ has a greater effect on the swelling of the shale than pure water and brine. It was also observed that the largest swelling displacement of shale occurred after a reaction with the $H_2O-scCO_2$ solution. The results of a series of the destructive and nondestructive tests indicate that although each of the property changes of the rock differed depending on the reaction conditions, the $H_2O-scCO_2$ solution had the greatest effect. In this study, shale was highly sensitive to the reaction conditions. These results provide fundamental information pertaining to the stability of $CO_2$ storage sites due to physical and chemical reactions between the rocks in these sites and $scCO_2$.

Exploring Science Teacher Agency as Agent of Change: The Case of Distance Learning Practice Due to COVID-19 (변화의 주체로서 과학 교사의 행위주체성 탐색 -COVID-19에 따른 원격 수업 실행 사례를 중심으로-)

  • Lee, Hyekeoung;Kim, Heui-Baik
    • Journal of The Korean Association For Science Education
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    • v.41 no.3
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    • pp.237-250
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    • 2021
  • Teachers play a key role in designing a students' learning experience. Teachers are asked to interpret the context in which they are located and to adjust their practice to fit circumstantial needs based on their teacher agency. In this study, we explore the emergence of teacher agency in distance learning caused by COVID-19 and we analyze factors shaping the teacher agency. For this purpose, we interviewed six secondary science teachers who practiced distance learning in 2020. Semi-constructed interviews and their artifacts were collected and analyzed. This study shows that teacher agency is captured when they respond to circumstantial change and modify their practice to achieve their professional purpose or adjust their practice in space for maneuvering or keep their practice consistent. This study also analyzes the factors that affect the emergence of teacher agency in two dimensions. One is individual and the other is contextual. In the individual dimension, educational values shaped by his/her experiences and short/long-term goals for the future support the emergence of teacher agency. In the contextual dimension, there are collaborative and flexible culture shared by the community, co-operation within the teacher community, and material support. On the other hand, in the individual dimension, the teachers' sense of their role, and no reflection for own practice constrain the emergence of teacher agency, and in the contextual dimension, performativity discourse and strong requirement without guidance constrain the emergence of teacher agency. We suggest an effective lens for establishing a strategy that support teachers' professional practice and the emergence of teacher agency.

Analysis of Hydrodynamics in a Directly-Irradiated Fluidized Bed Solar Receiver Using CPFD Simulation (CPFD를 이용한 태양열 유동층 흡열기의 수력학적 특성 해석)

  • Kim, Suyoung;Won, Geunhye;Lee, Min Ji;Kim, Sung Won
    • Korean Chemical Engineering Research
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    • v.60 no.4
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    • pp.535-543
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    • 2022
  • A CPFD (Computational particle fluid dynamics) model of solar fluidized bed receiver of silicon carbide (SiC: average dp=123 ㎛) particles was established, and the model was verified by comparing the simulation and experimental results to analyze the effect of particle behavior on the performance of the receiver. The relationship between the heat-absorbing performance and the particles behavior in the receiver was analyzed by simulating their behavior near bed surface, which is difficult to access experimentally. The CPFD simulation results showed good agreement with the experimental values on the solids holdup and its standard deviation under experimental condition in bed and freeboard regions. The local solid holdups near the bed surface, where particles primarily absorb solar heat energy and transfer it to the inside of the bed, showed a non-uniform distribution with a relatively low value at the center related with the bubble behavior in the bed. The local solid holdup increased the axial and radial non-uniformity in the freeboard region with the gas velocity, which explains well that the increase in the RSD (Relative standard deviation) of pressure drop across the freeboard region is responsible for the loss of solar energy reflected by the entrained particles in the particle receiver. The simulation results of local gas and particle velocities with gas velocity confirmed that the local particle behavior in the fluidized bed are closely related to the bubble behavior characterized by the properties of the Geldart B particles. The temperature difference of the fluidizing gas passing through the receiver per irradiance (∆T/IDNI) was highly correlated with the RSD of the pressure drop across the bed surface and the freeboard regions. The CPFD simulation results can be used to improve the performance of the particle receiver through local particle behavior analysis.

A Comparative Study on the Characteristics of Cultural Heritage in China and Vietnam (중국과 베트남의 문화유산 특성 비교 연구)

  • Shin, Hyun-Sil;Jun, Da-Seul
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.40 no.2
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    • pp.34-43
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    • 2022
  • This study compared the characteristics of cultural heritage in China and Vietnam, which have developed in the relationship of mutual geopolitical and cultural influence in history, and the following conclusions were made. First, the definition of cultural heritage in China and Vietnam has similar meanings in both countries. In the case of cultural heritage classification, both countries introduced the legal concept of intangible cultural heritage through UNESCO, and have similarities in terms of intangible cultural heritage. Second, while China has separate laws for managing tangible and intangible cultural heritages, Vietnam integrally manages the two types of cultural heritages under a single law. Vietnam has a slower introduction of the concept of cultural heritage than China, but it shows high integration in terms of system. Third, cultural heritages in both China and Vietnam are graded, which is applied differently depending on the type of heritage. The designation method has a similarity in which the two countries have a vertical structure and pass through steps. By restoring the value of heritage and complementing integrity through such a step-by-step review, balanced development across the country is being sought through tourism to enjoy heritage and create economic effects. Fourth, it was confirmed that the cultural heritage management organization has a central government management agency in both countries, but in China, the authority of local governments is higher than that of Vietnam. In addition, unlike Vietnam, where tangible and intangible cultural heritage are managed by an integrated institution, China had a separate institution in charge of intangible cultural heritage. Fifth, China is establishing a conservation management policy focusing on sustainability that harmonizes the protection and utilization of heritage. Vietnam is making efforts to integrate the contents and spirit of the agreement into laws, programs, and projects related to cultural heritage, especially intangible heritage and economic and social as a whole. However, it is still dependent on the influence of international organizations. Sixth, China and Vietnam are now paying attention to intangible heritage recently introduced, breaking away from the cultural heritage protection policy centered on tangible heritage. In addition, they aim to unite the people through cultural heritage and achieve the nation's unified policy goals. The two countries need to use intangible heritage as an efficient means of preserving local communities or regions. A cultural heritage preservation network should be established for each subject that can integrate the components of intangible heritage into one unit to lay the foundation for the enjoyment of the people. This study has limitations as a research stage comparing the cultural heritage system and preservation management status in China and Vietnam, and the characteristic comparison of cultural heritage policies by type remains a future research task.

Effect of various surface treatment methods of highly translucent zirconia on the shear bond strength with resin cement (고투명도 지르코니아의 다양한 표면처리 방법이 레진시멘트와의 전단결합강도에 미치는 영향)

  • Yu-Seong Kim;Jin-Woo Choi;Hee-Kyung Kim
    • The Journal of Korean Academy of Prosthodontics
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    • v.61 no.3
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    • pp.179-188
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    • 2023
  • Purpose. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength of two types of zirconia (3-TZP and 5Y-PSZ) with resin cement. Materials and methods. Two different types of zirconia specimens with a fully sintered size of 14.0×14.0×2.0 mm3 were prepared, polished with 400, 600, and 800 grit silicon carbide paper, and buried in epoxy resin. They were classified into four groups each control, sandblasting, primer, and sandblasting & primer. Cylindrical resin adhered to the surface-treated zirconia with resin cement. It was stored in distilled water (37℃) for 24 hours, and a shear bond strength test was performed. The normality of the experimental group was confirmed with the Kolmogorov-Smirnov & Shapiro-Wilk test. The interaction and statistical difference were analyzed using a two-way ANOVA. A post-hoc analysis was performed using Dunnett T3. Results. As a result of two-way ANOVA, there was no significant difference in shear bonding strength between zirconia types (P > .05), but there was a significant correlation in the sandblasting, primer, and alumina sandblasting & primer group (P < .05). Dunnett T3 post-test showed that, regardless of the type of zirconia, shear bonding strength was sandblasting & primer > Primer > sandblasting > control group (P < .05). Conclusion. There was no difference in shear bond strength between the types of zirconia. The highest shear bond strength was shown when the mechanical and chemical treatments of the zirconia surface was performed simultaneously.

The Influence of Loyalty Program on the Effect of Customer Retention: Focused on Education Service Industry (고객보상 프로그램이 고객 유지에 미치는 효과: 교육 서비스 산업을 중심으로)

  • Jeon, Hoseong
    • Asia Marketing Journal
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    • v.13 no.3
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    • pp.25-53
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    • 2011
  • This study probes the effect of loyalty program on the customer retention based on the real transaction data(n=2,892) acquired from education service industry. We try to figure out the outcomes of reward program through more than 1 year-long data gathered and analyzed according to quasi-experimental design(i.e., before and after design). We adopt this kinds of research scheme in regard that previous studies measured the effect of loyalty program by dividing the customers into two group(i.e., members vs. non-members) after the firms or stores had started the program. We believe that it might not avoid the self-selection bias. The research questions of this study could be explained such as: First, most research said that the loyalty programs could increase the customer loyalty and contribute to the sustainable growth of company. But there are little confirmation that this promotional tool could be justified in terms of financial perspective. Thus, we are interested in both the retention rate and financial outcomes caused by the introduction of loyalty programs. Second, reward programs target mainly current customer. Especially CRM(customer relationship management) said that it is more profitable for company to build positive relationship with current customer instead of pursuing new customer. And it claims that reward program is excellent means to achieve this goal. For this purpose, we check in this study whether there is a interaction effect between loyalty program and customer type in retaining customer. Third, it is said that dis-satisfied customers are more likely to leave the company than satisfied customers. While, Bolton, Kannan and Bramlett(2000) claimed that reward program could contribute to minimize the effect of negative service by building emotional link with customer, it is not empirically confirmed. This point of view explained that the loyalty programs might work as exit barrier to current customer. Thus, this study tries to identify whether there is a interaction effect between loyalty program and service experience in keeping customer. To achieve this purpose, this study adopt both Kaplan-Meier survival analysis and Cox proportional hazard model. The research outcomes show that the average retention period is 179 days before introducing loyalty program but it is increased to 227 days after reward is given to the customers. Since this difference is statistically significant, it could be said that H1 is supported. In addition, the contribution margin coming from increased transaction period is bigger than the cost for administering loyalty programs. To address other research questions, we probe the interaction effect between loyalty program and other factors(i.e., customer type and service experience) affecting it. The analysis of Cox proportional hazard model said that the current customer is more likely to engage in building relationship with company compared to new customer. In addition, retention rate of satisfied customer is significantly increased in relation to dis-satisfied customer. Interestingly, the transaction period of dis-satisfied customer is notably increased after introducing loyalty programs. Thus, it could be said that H2, H3, and H4 are also supported. In summary, we found that the loyalty programs have values as a promotional tool in forming positive relationship with customer and building exit barrier.

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STUDY ON THE RELATIONSHIP BETWEEN SEROTONIN SYSTEM AND PSYCHOPATHOLOGY IN TOURETTE'S DISORDER (Tourette씨병의 Serotonin계와 정신병리와의 상호관계에 관한 연구)

  • Cho, Soo-Churl;Shin, Yun-O;Suh, Yoo-Hun
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.7 no.1
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    • pp.77-91
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    • 1996
  • In order to elucidate the biological etiology and the effects of comorbidity on biological variables in tic disorders, plasma serotonin (5-hydroxlfryptamine, 5-HT) and 5-hydroxy- indoleacetic acid (5-HIAA) we.e measured in 87 tic disorders and 30 control subjects. The 87 tic disorder were composed of 45 Tourette's disorder(TS), 22 chronic motor tic disorders (CMT) and 20 transient tic disorders (TTD). Among these patients,43 patients were pure tic disorder (PT), 28 subject also had attention deficit hyperactivity disorder (T+ADHD) and 16 subjects had obsessive compulsive disorders (T+ OCD) as comorbid disorders. The results are summarized as follows : 1) Plasma 5-HT levels showed significant positive correlations with plasma 5-HIAA levels (Pennon r=0.77, p<0.05). 2) Plasma 5-HT and 5-HIAA levels showed no significant correlation with age in tic disorders. 3) Plasma 5-HIAA and 5-HT levels showed no significant correlations with age in control subjects. 4) There was significant difference in plasma 5-HT levels among TS, CMT, TTD and control groups (ANOVA F=34.48, df=3, 113, p<0.01), and post-hoc test using Scheffe method showed significant differences between control and TS, control and CMT, control and ITD groups. But, post-hoc test showed no significant differences between TS and CMT, TS and TTD, CMT and TTD groups. 5) There was significant difference in plasma 5-HIAA levels among TS, CMT, TTD and control groups (ANOVA F=26.48, df=3, 113, p<0.01), and post-hoc test using Scheffe method showed significant differences between control and TS, control and CMT, control and TTD groups. But, post-hoc test showed no significant differences between TS and CMT, TS and TTD, CMT and TID groups.f) There was significant difference in plasma 5-HT and 5-HIAA levels among PT, T+ADHD, T+OCD and contol groups (ANOVA 5-HT, F=37.59, df=3, 113, p<0.01, 5-HIAA, F=27.37, df=3, 113, p<0.01), and post-hoc test using Scheffe method showed signiscant differences between control and PT, control and T+ADHD and control and T+OCB. But, post-hoc test showed no significant differences between PT and T+ADHD, PT and T+ OCD and T+ADHD and T+ OCD. These results show that decreased 5-HT and 5-HIAA levels may play a role in the genesis of tic disorders, but these findings have no significant correlations with the severity of tic disorders. And the comorbid disorders of tics may have minimal effects on the biochemical abnormalities. Future studies must be focused on the effects of serotonin agonists and antagonists on tic disorders and molecular biological methodology may enhance to elucidate the mechanisms of these abnormal findings.

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AN EXPLORATORY STUDY TO DETERMINE HOW ADOLESCENT STUDENT NURSES VIEW PEDIATRIC NURSING EXPERIENCE AS STRESSFUL SITUATION (소아과 간호학 실습시에 느끼는 성년기 간호학생들의 긴장감에 대한 실험적 연구)

  • Oh, Kasil
    • Journal of Korean Academy of Nursing
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    • v.4 no.3
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    • pp.33-56
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    • 1974
  • 간호를 장래의 전문직으로 택하려고 공부하는 간호학생들은 완전한 성인으로서의 발달 과정중 후기 성년기에 속한다. 이시기는 자아를 발견하고 인간이 무엇을 믿으며 인간의 가치가 무엇인가를 추구하는 중요한 시기이다. 다시 말해서 어른과 어린이의 과도기에 서서 자신의 이상적 가치와 기성사회의 기존 가치를 잘 융화시켜 독립된 인간으로서 성숙하려는 노력의 시기이다. 그러므로 성년기의 갈등은 인생의 어느 시기보다도 그 정도가 심하게 나타난다. 간호학생들은 이상의 일반적인 성년기 발달의 요구 외에도 간호대학이라는 특수한 배움의 여건 때문에 좀 더 심각한 문제에 대두된다. 특히 소아과 간호대학이라는 실습환경은 여러 가지 복잡한 병실 사정으로 많은 긴장감을 주는 학습경험이다. 어린이의 간호에는 그들의 발달과정에 따른 다양한 역활이 요구된다. 또한 병원이라는 낯선 환경과 어머니를 떨어져야하는 두려움으로 불안한 어린이와 그 어린이의 불안과 두려움으로 인해 우울과 죄의식에 있는 어머니의 간호는 여러 면에서 성년기 학생들에게 긴장감을 일으키게 하는 요인이 된다. 본 연구의 문헌조사는 주로 미국 문헌에 나타난 간호 대학생들의 성년기 성숙을 위한 발달의 요구와, 소아병실의 복잡한 여건으로 발생되는 긴장감을 다루고 있다. 문헌을 기초로 하여 저자는 긴장감을 주는 간호활동을 크게 다섯 부군으로 묶었다. 1. 어린이 환자의 신체적 간호, 2. 어린이 환자나 부모와의 원만한 대화와 상호관계를 위한 간호활동 3. 소아병실에서 요구되는 다양한 간호원의 역활 4. 어린이나 부모의 간호에 대한 의뢰심 5. 간호의 가치나 이상적 간호. 연구방법으로는 49개의 폐쇄식 질문 항목을 가진 질문지를 사용하였다. 질문 항목들은 문헌연구에서 소아과 간호학 실습시 학생들이 긴장감을 느낀다고 밝혀진 내용들이 다. 학생들은 자신의 경험을 "긴장감이 없었다. ""긴장감이 있었다. ""심한 긴장감이 있었다. ""실습 중 경험이 없었다. "의 사항 중 택일을 하게 되어 있다. 연구대상으로는 모 대학교 간호대학 학생으로 산부인과 간호학 실습을 마친 후 소아과 간호학 실습 8주를 완료한 4학년 학생 42명이었다. 자료분석의 결과는 대부분의 학생들에게 소아과 간호학 실습은 긴장감을 주는 경험이 있다고 나타났다. 다음은 연구결과 주목할만한 몇 가지 사항들이다. 1. 어린이 환자의 신체적 간호는 성년기 학생들에게 긴장감을 주는 실습 경험이었다. 특별히 심하게 긴장감을 주었던 간호활동은 어린이환자의 상태가 중한 경우로, 장기간 앓는 아이, 선천성 기형이 있는 아이, 회복이 불가능하여 죽게될 아이나 사망하는 경우의 어린이 간호였다. 이 결과는 간호학의 기본과정 즉, 기초간호학이나 내 외과 간호학 실습만으로 소아과 간호학 실습을 위한 충분한 준비가 되지 못한다는 것을 뜻 할 수도 있다. 한편, 문헌연구에서 밝힌바와 같이 어리고 연약해 보이는 어린이들의 신체조건이 학생들의 간호활동을 어렵게 하는 경우도 될 수 있겠다. 2. 간호학생들의 어린이 환자와의 대화나 원만한 인간관계에서의 긴장감은 이 연구결과로 평가나 제언이 힘들다. 조사결과에서 학생들은 주로 어린이의 상태가 좋지 않은 경우에 심한 긴장감을 가졌고 일반적인 간호의 경우에는 별로 긴장감이 없었다. 이것은 질병의 상태나 화제, 이야기 할 때의 상황에 따라 긴장감의 여부가 달라질 수 있다는 결론이 되겠다. 3. 소아병실에서의 다양한 역활을 수행하는 것은 비교적 긴장감이 많이 생기는 간호활동으로 나타났다. 그러나 재미있는 사실은 학생들이 간호원으로서의 전문가적인 입장에서, 환자나 보호자를 가르칠때는 별로 문제가 없었으나 어린이 기르는 방법이나 어린이 이해면에서 좀 더 잘 안다고 생각되는 어머니가 지켜 볼때의 어린이 간호에는 긴장감을 가진다는 사실이다. 이것은 Jewett의 연구에서 밝힌바와는 상반되는 결과다. 그의 연구에서 학설들은 부모나 어머니들에 의해 전문가로서 인정받고 기대되는 경우가 제일 어려운 경험이 있다고 밝혔다. 4. 어린이 환자나 그들 부모의 간호에 대한 의뢰심은 학생들에게 심한 긴장감을 주는 경험이 있다. 특히 신체적 간호에 대해 의뢰하는 경우에는 더 심한 긴장감을 준다고 표현한다. 일반적으로 부모가 병실에 상주하는 경우에는 그들의 의뢰심이 심하며 이것은 학생들에게 감당하기 힘든 긴장과 어려움을 주게된다. 왜냐하면 성년기의 학생들은 그들 자신이 먼저 타인에게서 이해받기를 원하며 또 관용을 베풀어주기를 원하는데 그것을 남에게 주어야 하는 입장은 학생들을 긴장되게 하는 실습활동인 것이다. 5. 학생들은 그들이 배운 간호의 이상이나 가치가 실습지에서의 여러 경우와 맞지 않는 것을 보았을 때 극심한 긴장감을 갖는다고 밝혔다. 의사나 병원 행정의 사실이 자신의 이상과 맞지 않는다는 것보다는 간호원의 간호업무의 차이에서 더 비판적인 반응을 보였다. 대부분의 성년기 학생들은 그들의 이상적인 간호원상을 그들의 선배나 실무 간호원 중에서 찾으려는 시기에 그들의 간호활동이 이론과 다른 점이나 학생 자신의 소아과 간호의 가치와 다른 것을 보았을 때는 심한 반감과 긴장감을 갖게된다. 이 문제는 어린 사람이 윗 어른과 함께 동료의식을 갖고 일하기 어려운 한국적 사회구조 때문에 더 심하게 긴장감을 주는 경험인지도 모른다. 선배 간호원의 전문인으로서의 권위와 어린이 환자 보호자의 어른으로서의 권위 사이에서 자신의 이상과 가치의 추구는 용이하지 않으며 내적 갈등은 어쩔수 없는 일 일 것이다. 6. 대부분 높은 백분율의 긴장 반응은 죽음이나 환자의 사망에 관련된 간호활동 항목에서 나타났다. 이 연구의 대상 학생들은 2, 3학년에서 죽음에 대한 강의를 들었지만 이 연구 결과에 의하면 충분한 학습 경험이 주어진 것 같지 않다. 어떠한 경우의 죽음에라도 어린이 환자나 그 보호자들의 심리를 잘 이해하고 반응을 잘 관찰해서 적절한 간호를 해 줄 수 있는 다양한 방법의 학습 경험이 필요하다고 보겠다. 7. 학생들의 긴장도가 어린이 간호에 더 심한가, 보호자 간호에 더 심한가를 알기 위한 비교 결과는 비교적 비슷한 정도로 나타났다. 8. 학생들의 소아과 간호학 실습시의 긴장도는 과거의 병실 실습기간의 장, 단이나 가정에서의 어린인 간호의 경험과는 별 연관성이 없었다. 연구의 대상자가 적기 때문에 단정을 하기는 힘이 들지만 소아과 간호학 실습이 다른 병실의 실습과는 분리되어서 완전히 다르게 다루어 져야만 하며 간호교육자들의 주의 깊은 관심과 노력이 필요한 실습교육이 라 하겠다. 이상의 전반적인 고찰에 의하면 한국 성년기 간호학생들의 소아과 간호학 실습은 미국의 경우와 마찬가지로 긴장감을 주는 경험이다. 문화배경의 다른 점은 무시하고라도 Davis와 Oleson이 결론한 바와 같이 "간호대 학생은 어디를 막론하고 다 같은 성격과 문제를 가지고 있다. " 앞으로 보다 효과적인 학생들의 소아과 간호학 실습을 위한 연구를 위해 다음의 몇 가지를 본 연구의 결과를 가지고 제언한다. 1. 보다 여러 지역에서 다양한 교육 방법을 가진 학교의 학생을 대상으로 한 연구의 필요성. 2. 학생들이 실습 전 선입견이나 이미 들어서 생긴 긴장감의 개입 여부를 밝힐 수 있는 연구. 3. 학생 개인의 과거 경침이 긴장감 유발에 미치는 영향을 위한 연구 4. 이 연구의 결과를 입증할 수 있는 종단적 연구. 5. 이 연구에서 나타난 긴장감이 학습 행위에 미치는 영향을 알기 위한 관찰적 연구. 이 연구를 위해 많은 도움을 주셨던 보스턴대학의 Dr. Kennedy와 연세대학의 여러 선생님께 심심한 감사를 드립니다.

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The Production and Correlation of Silica Induced Proinflammatory Cytokines and TGF-$\beta$ from Monocytes of Balb/C Mice (Balb/C mouse의 폐장대식세포에서 유리규산 자극에 의한 Proinflammatory Cytokine과 TGF-$\beta$의 생성 및 상관관계)

  • Ki, Shin-Young;Kim, Eun-Young;Kim, Mi-Ho;Uh, Soo-Taek;Kim, Yong-Hoon;Park, Choon-Sik;Lee, Hi-Bal
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.4
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    • pp.823-834
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    • 1998
  • Background: Chronic inhalation of silica induces the lung fiborsis. The alveolar macrophages ingest the inhaled silica; they liberate the pro-inflammatory cytokines such as IL-1$\beta$, IL-6, TNF-$\alpha$ and fibrogenic cytokines, TGF-$\beta$ and PDGF. Cytokines liberated from macrophage have pivotal role in pulmonary fibrosis. There is a complex cytokine network toward fibrosis. However, the exact roles and the interaction among the proinflammatory cytokines and TGF-$\beta$, a fibrogenic cytokine, have not been defined, yet. In this study, we investigated silica induced IL-1$\beta$, IL-6, TNF-$\alpha$ and TGF-$\beta$ production and the effect of IL-1$\beta$, IL-6, TNF-$\alpha$ on the production of TGF-$\beta$ from lung macrophages of Balb/C mice. Method: We extracted the lung of Balb/C mice and purified monocytes by Percoll gradient method. Macrphages were stimulated by silica ($SiO_2$) in the various concentration for 2, 4, 8, 12, and 24 hours. The supernatants were used for the measurement of protein levels by bioassay, and cells for the levels of mRNA by in situ hybridization. Results: The production of IL-6 was not observed till 4 hours, and reached the peak levels at 8 hours after stimulation of silica. The production of TNF-$\alpha$ increased from 2 hours and reached the peak levels at 4 hours after stimulation of silica. The spontaneous TGF-$\beta$ production reached the peak levels at 24 hours. TNF-$\alpha$ upregulated the silica induced TGF-$\beta$ production. Silica induced TGF-$\beta$ production was blocked by pretreated anti-TNF-$\alpha$ antibody. In situ hybridization revealed the increased positive signals at 4 hours in IL-6, at 4 hours TNF-$\alpha$ and 12 hours in TGF-$\beta$. Conclusion: The results above suggest that silica induced the sequential production of IL-6, 1NF-$\alpha$ and TGF-$\beta$ from macrophages and TNF-$\alpha$ upregultaes the production of TGF-$\beta$ from silica-induced macrophages.

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Influence of the Combination of Casein and Isolated Soyprotein with or without Methionine Supplementation on the Growth, Metabolism, and Body Composition of Growing Rats (카제인과 대두단백질(大豆蛋白質)의 혼합(混合) 및 Methionine보충(補充)이 흰쥐의 성장(成長), 체내(體內) 대사(代謝) 및 체조성(體組成)에 미치는 영향)

  • Park, Young Ja;Han, In Kyu
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.12 no.2
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    • pp.73-83
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    • 1983
  • This experiment was conducted to study effects of different sources of protein, and of the different combination ratios of the two protein supplemented or unsupplemented with methionine on the growth and body metabolism of the growing male rats. Casein and isolated soyprotein (ISP) were combined at different ratios of 100:0, 80:20, 50:50, 20:80 and 0:100 to supply the constant levels of dietary energy and protein of 3,600kcal/kg and 20%, respectively. Each combination was supplemented with either 0 or 0.3% methionine. Results obtained in these experiments were summarized as follows: The body weight and weight gain in the ISP diet were the lowest, but were increased with the increase of ratios of casein to ISP. The body weight gain in the ISP diet supplemented with methionine was similar to that in the combination diets of casein and ISP. The combination diets of casein and ISP supplemented with methionine had the higher weight gain than the casein diet. The food intake in the casein diet was the highest, and was increased with the increase of ratios of casein to ISP, and was lowered with methionine supplementation. The food intake in the ISP diet was the lowest and was not increased with methionine supplementation to the ISP diet. The food efficiency ratio of the combination diets of casein and ISP was improved compared to those of either the casein or the ISP diets. The food efficiency ratio was improved in the diet of either casein of ISP supplemented with methionine, but was not improved in the combination diets of casein and ISP with methionine supplementation. The gross energy intake had direct relation with the food intake of rats and the relation was increased either in the casein diet of with the increase of the ratios of casein to ISP. The energy efficiency and protein efficiency ratios were improved in the diet of either casein of ISP by the supplementation of methionine, and the effect of methionine supplementation of the energy efficiency and protein efficiency atio was increased with the increase of the ratios of ISP to casein. The nitrogen intake and urinary nitrogen excretion of the casein diet were the highest and those of the ISP diet were the lowest. They were increased with the increase of ratios of casein to ISP. The nitrogen balance and retention were not significantly among the treatments. The gross energy intake and fecal and urinary energy were the highest in the casein diet but the digestible and metabolizable energy and the digestibility and metabolizability of energy were not significantly different among the treatments. The body fat content of rats was increased by supplementation of methionine but the body protein content was decreased (r=-0.65, p<0.01). The body fat content of rats was negatively correlated with body moisture content (r=-0.83, p<0.01). The liver weight was highly correlated with the carcass weight (r=0.79, p<0.01), and was increased by the methionine supplementation and by the increase of the ratios of casein to ISP.

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