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A Study on the Effect of Aroma Therapy on Anxiety and Pain Before and After Tooth Extraction (향기흡입법이 발치 전·후에 미치는 불안과 통증에 관한 연구)

  • Jeong, Mi-Ae
    • Journal of Korean society of Dental Hygiene
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    • v.4 no.1
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    • pp.105-117
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    • 2004
  • The purpose of this study was to examine the effect of aroma therapy on anxiety and pain before and after tooth extraction. The subjects in this study were 60 patients who felt severe anxiety and pain due to tooth extraction. The experiment was conducted from January through March, 2004, by organizing an experimental group and a control group with 30 patients each. The experimental group was asked to keep wearing lavender-containing necklaces from two days before tooth extraction to inhale lavender, and no such an action was taken to the control group. The collected data were analyzed with SPSS 10.0 program to obtain statistical data. and ${\times}2$ test and t-test were implemented. The findings of this study were as follows: 1. Regarding whether or not the experimental and control groups were homogeneous, men outnumbered women, and the largest number of the patients were in their 30s. Those who were married were more than the others who were unmarried in number, and those who lived with their spouses under the same roof together outnumbered the others who didn't, as the rate of the former stood at 65 percent in the experimental group and 86.4 percent in the control group. They expressed high satisfaction at their spouses, since 45 percent of the experimental group and 31 percent of the control group did it, but the difference between them and those who were unsatisfied was insignificant (pE0.347). By occupation, the largest number of people in the experimental group, which numbered 16.7 percent, were self-employed, and lots of patients in the control group were government workers. As for blood type, type A was most prevailing, which recorded 43.3 percent. By religion, 43 percent of the experimental group had no religion, whereas 36.7 percent of the control group were Christian. The most common monthly income ranged from 2 million to 2.5 million won. 2. There was little disparity in past pain experience between the two groups before aroma therapy was applied. The experimental group underwent more pain (6.15) than the control group (5.78), but the difference wasn't significant. The experimental group (90%) experienced more anxiety and fear than the control group(83%), but the difference was insignificant. This fact showed that there was little gap between the two groups in anxiety and fear caused by tooth extraction. Contrary to earlier expectation that pre-anxiety might not be the same. little significant difference was found. 3. After aroma therapy was applied, 50 percent of the experimental group and 23.3 percent of the control group suffered significantly less anxiety and fear about tooth extraction(${\times}2$=4.59, pE.05). And the experimental group exposed to aroma therapy was less nervous(3.0) than the control group(4.39), and the gap between the two was significant (t=13.37, pE.001). Therefore, aroma therapy had a good effect on alleviating their anxiety. During tooth extraction. 73.3 percent of the experimental group and 93.3 percent of the control group felt pain. The former group suffered Significantly less pain(${\times}2$=4.32, PE.05). Concerning the extent of pain, the experimental group(2.53) found it less painful to have their teeth extracted than the control group(5.50), and the gap between the two was significant(t=5.89, PE.05). 4. As to the effect of aroma therapy on alleviating anxiety or fear, the experimental group(33.3%) felt that aroma therapy let them more relieved. Every member of that group was willing to use aroma therapy again in the future, and 86.7 percent of that group perceived that aroma therapy made a difference to dental treatment. The experimental group responded to aroma therapy favorably, as every member of it had an intention to advise others to use that therapy.

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The Death Orientation of nursing students in Korea and China (한국과 중국 간호대학생의 죽음에 대한 의식)

  • Li, Zhen-Shu;Choe, Wha-Sook
    • Korean Journal of Hospice Care
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    • v.8 no.1
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    • pp.1-12
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    • 2008
  • Perpose: The purpose of this study was to investigate the perception of death between Korean and Chinese nursing students. And it will help develop curriculum for preparing death, the quality of hospice care, as well as nursing education and practice. Methods: Data was collected from 492 nursing students participated(248 Korean and 244 Chinese) by questionnaire designed for examining Death Orientation (Thorson & Powell, 1988). They were analyzed using Cronbach's Alpha coefficients, factor analysis, t-test, ANOVA and regression analysis (SPSS; win 12.0 version) Results: More than half of the Korean nursing students followed a religion (58.5%) while the majority of Chinese nursing students did not follow a religion (93.9%). In the view of the afterlife, nursing students in China had two views. 'I really don't know what happens after a person dies (30.3%)' and ‘There is no afterlife and death is the end (29.5%)’. On the other hand the Korean nursing students’ answer were, 'After dying, a person goes to heaven or hell (27.3%)' and 'I really don't know what happens after a person dies. (22.9%)' The study also found that the average of 25 items in Death Orientation is 2.36points of nursing students in Korea and 2.50points of nursing students in China. This means that the concern, anxiety and fear were of the middle level for the Chinese Students and were higher than Korean students (t=3.51, p=.000). In the low factor of death orientation, those in Korea had higher 'anxiety of burden to family' than those in China (t=-3.50, p=.001). The nursing students in China had higher 'anxiety of the unknown (t=4.96, p=.000)', 'fear of suffering (t=6.88, p=.000), 'fear of extinction body and life (t=5.20, p=.000), 'fear of lost self-control(t=2.12, p=.034)', and 'anxiety of future existence and nonexistence (t=2.33, p=.020)' than those in Korea. There was no statistically significant difference for the 'concern of body and fear of identity lost' category. The death orientation of Korean nursing students had statistically significant differences according to age (t=3.20, p=.002), religion (t=2.56, p=.011), and afterlife (F=4.64, p=.000). The contribution of Death Orientation had a statistically significant difference, the afterlife variable (0.735, p=0.001). The death orientation of Chinese nursing students did not have any statistically significant differences. Conclusion: In conclusion, there were differences in death orientation between Korean and Chinese nursing students. In particular, those who believed in afterlife showed acceptance of death. The results of this study suggest that nursing curricula should include education program on death and spiritual nursing. Additional studies are needed to establish death education in China with careful considerations on Chinese policies, cultures and social systems.

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Effectiveness of Home Economics Class on self-esteem and stress of middle school students (가정과수업이 중학생의 자아존중감과 스트레스에 미치는 효과)

  • Park, Mi Jeong
    • Journal of Korean Home Economics Education Association
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    • v.29 no.3
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    • pp.15-32
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    • 2017
  • This study investigated the effectiveness of home economics class on self-esteem and stress of middle school students. Data were collected from self-reported inventory of the middle school students in Y city of Gyeonggi province and 165 data copies were used for analyses. Data were analyzed for frequency, percentage, mean, standard deviation, Cronbach's ${\alpha}$, t-test, corelation and dependent t-test using SPSS/PC 18.0 program. The results were as follows. First, the average of positive self-esteem was 2.74 and that of negative self-esteem was 1.90 on a 4 Likert scale. The range of stress level was 1.88~2.48 on a 5 Likert scale. Life satisfaction was 3.90 and helpfulness of home economics class was 3.89 on a 5 point Likert scale, which means moderately high. Second, examining differences in variables according to gender, there were statistically significant differences in stress regarding family for both pre- and post-tests. Third, helpfulness of home economics class had positive correlation with positive self-esteem and life satisfaction and had negative correlation with negative self-esteem and stress, which means that home economics class enhance life satisfaction and positive self-esteem and lessen negative self-esteem and stress of middle students. Fourth, as a result of comparison of pre and post-tests, positive self-esteem, life satisfaction, and helpfulness of home economics class increased statistically after home economics classes, while stress regarding school life decreased statistically. Even though students' growth and changes resulting from learning other subjects were not controlled, it was meaningful that effectiveness of home economics class were examined and helpful information for enhancing perception of home economics education were provided.

Open Skies Policy : A Study on the Alliance Performance and International Competition of FFP (항공자유화정책상 상용고객우대제도의 제휴성과와 국제경쟁에 관한 연구)

  • Suh, Myung-Sun;Cho, Ju-Eun
    • The Korean Journal of Air & Space Law and Policy
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    • v.25 no.2
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    • pp.139-162
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    • 2010
  • In terms of the international air transport, the open skies policy implies freedom in the sky or opening the sky. In the normative respect, the open skies policy is a kind of open-door policy which gives various forms of traffic right to other countries, but on the other hand it is a policy of free competition in the international air transport. Since the Airline Deregulation Act of 1978, the United States has signed an open skies agreement with many countries, starting with the Netherlands, so that competitive large airlines can compete in the international air transport market where there exist a lot of business opportunities. South Korea now has an open skies agreement with more than 20 countries. The frequent flyer program (FFP) is part of a broad-based marketing alliance which has been used as an airfare strategy since the U.S. government's airline deregulation. The membership-based program is an incentive plan that provides mileage points to customers for using airline services and rewards customer loyalty in tangible forms based on their accumulated points. In its early stages, the frequent flyer program was focused on marketing efforts to attract customers, but now in the environment of intense competition among airlines, the program is used as an important strategic marketing tool for enhancing business performance. Therefore, airline companies agree that they need to identify customer needs in order to secure loyal customers more effectively. The outcomes from an airline's frequent flyer program can have a variety of effects on international competition. First, the airline can obtain a more dominant position in the air flight market by expanding its air route networks. Second, the availability of flight products for customers can be improved with an increase in flight frequency. Third, the airline can preferentially expand into new markets and thus gain advantages over its competitors. However, there are few empirical studies on the airline frequent flyer program. Accordingly, this study aims to explore the effects of the program on international competition, after reviewing the types of strategic alliance between airlines. Making strategic airline alliances is a worldwide trend resulting from the open skies policy. South Korea also needs to be making open skies agreements more realistic to promote the growth and competition of domestic airlines. The present study is about the performance of the airline frequent flyer program and international competition under the open skies policy. With a sample of five global alliance groups (Star, Oneworld, Wings, Qualiflyer and Skyteam), the study was attempted as an empirical study of the effects that the resource structures and levels of information technology held by airlines in each group have on the type of alliance, and one-way analysis of variance and regression analysis were used to test hypotheses. The findings of this study suggest that both large airline companies and small/medium-size airlines in an alliance group with global networks and organizations are able to achieve high performance and secure international competitiveness. Airline passengers earn mileage points by using non-flight services through an alliance network with hotels, car-rental services, duty-free shops, travel agents and more and show high interests in and preferences for related service benefits. Therefore, Korean airline companies should develop more aggressive marketing programs based on multilateral alliances with other services including hotels, as well as with other airlines.

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Study on PM10, PM2.5 Reduction Effects and Measurement Method of Vegetation Bio-Filters System in Multi-Use Facility (다중이용시설 내 식생바이오필터 시스템의 PM10, PM2.5 저감효과 및 측정방법에 대한 연구)

  • Kim, Tae-Han;Choi, Boo-Hun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.5
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    • pp.80-88
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    • 2020
  • With the issuance of one-week fine dust emergency reduction measures in March 2019, the public's anxiety about fine dust is increasingly growing. In order to assess the application of air purifying plant-based bio-filters to public facilities, this study presented a method for measuring pollutant reduction effects by creating an indoor environment for continuous discharge of particle pollutants and conducted basic studies to verify whether indoor air quality has improved through the system. In this study conducted in a lecture room in spring, the background concentration was created by using mosquito repellent incense as a pollutant one hour before monitoring. Then, according to the schedule, the fine dust reduction capacity was monitored by irrigating for two hours and venting air for one hour. PM10, PM2.5, and temperature & humidity sensors were installed two meters front of the bio-filters, and velocity probes were installed at the center of the three air vents to conduct time-series monitoring. The average face velocity of three air vents set up in the bio-filter was 0.38±0.16 m/s. Total air-conditioning air volume was calculated at 776.89±320.16㎥/h by applying an air vent area of 0.29m×0.65m after deducing damper area. With the system in operation, average temperature and average relative humidity were maintained at 21.5-22.3℃, and 63.79-73.6%, respectively, which indicates that it satisfies temperature and humidity range of various conditions of preceding studies. When the effects of raising relatively humidity rapidly by operating system's air-conditioning function are used efficiently, it would be possible to reduce indoor fine dust and maintain appropriate relative humidity seasonally. Concentration of fine dust increased the same in all cycles before operating the bio-filter system. After operating the system, in cycle 1 blast section (C-1, β=-3.83, β=-2.45), particulate matters (PM10) were lowered by up to 28.8% or 560.3㎍/㎥ and fine particulate matters (PM2.5) were reduced by up to 28.0% or 350.0㎍/㎥. Then, the concentration of find dust (PM10, PM2.5) was reduced by up to 32.6% or 647.0㎍/㎥ and 32.4% or 401.3㎍/㎥ respectively through reduction in cycle 2 blast section (C-2, β=-5.50, β=-3.30) and up to 30.8% or 732.7㎍/㎥ and 31.0% or 459.3㎍/㎥ respectively through reduction in cycle 3 blast section (C-3, β=5.48, β=-3.51). By referring to standards and regulations related to the installation of vegetation bio-filters in public facilities, this study provided plans on how to set up objective performance evaluation environment. By doing so, it was possible to create monitoring infrastructure more objective than a regular lecture room environment and secure relatively reliable data.

A Critical Evaluation of the Correlation Between Biomarkers of Folate and Vitamin $B_{12}$ in Nutritional Homocysteinemia (엽산과 비타민 $B_{12}$ 결핍에 의한 호모시스테인혈증 흰쥐의 조직내 비타민 지표간의 상관관계 분석)

  • Min, Hye-Sun;Kim, Mi-Sook
    • Journal of Nutrition and Health
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    • v.42 no.5
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    • pp.423-433
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    • 2009
  • Folate and vitamin $B_{12}$ are essential cofactors for homocysteine (Hcy) metabolism. Homocysteinemia has been related with cardiovascular and neurodegenerative disease. We examined the effect of folate and/or vitamin $B_{12}$ deficiency on biomarkers of one carbon metabolism in blood, liver and brain, and analyzed the correlation between vitamin biomarkers in mild and moderate homocysteinemia. In this study, Sprague-Dawley male rats (5 groups, n = 10) were fed folatesufficient diet (FS), folate-deficient diet (FD) with 0 or 3 g homocystine (FSH and FDH), and folate-/vitamin $B_{12}$-deficient diet with 3 g homocystine (FDHCD) for 8 weeks. The FDH diet induced mild homocysteinemia (plasma Hcy 17.41 ${\pm}$ 1.94 nmol/mL) and the FDHCD diet induced moderate homocysteinemia (plasma Hcy 44.13 ${\pm}$ 2.65 nmol/mL), respectively. Although liver and brain folate levels were significantly lower compared with those values of rats fed FS or FSH (p < 0.001, p < 0.01 respectively), there were no significant differences in folate levels in liver and brain among the rats fed FD, FDH and FDHCD diet. However, rats fed FDHCD showed higher plasma folate levels (126.5 ${\pm}$ 9.6 nmol/L) compared with rats fed FD and FDH (21.1 ${\pm}$ 1.4 nmol/L, 22.0 ${\pm}$ 2.2 nmol/L)(p < 0.001), which is the feature of "ethyl-folate trap"by vitamin $B_{12}$ deficiency. Plasma Hcy was correlated with hepatic folate (r = -0.641, p < 0.01) but not with plasma folate or brain folate in this experimental condition. However, as we eliminated FDHCD group during correlation test, plasma Hcy was correlated with plasma folate (r = -0.581, p < 0.01), hepatic folate (r = -0.684, p < 0.01) and brain folate (r = -0.321, p < 0.05). Hepatic S-adenosylmethionine (SAM) level was lower in rats fed FD, FDH and FDHCD than in rats fed FS and FSH (p < 0.001, p < 0.001 respectively) and hepatic S-adenosylhomocysteine (SAH) level was significantly higher in those groups. The SAH level in brain was also significantly increased in rats fed FDHCD (p < 0.05). However, brain SAM level was not affected by folate and/or vitamin $B_{12}$ deficiency. This result suggests that dietary folate- and vitamin B12-deficiency may inhibit methylation in brain by increasing SAH rather than decreasing SAM level, which may be closely associated with impaired cognitive function in nutritional homocysteinemia.

Differential Effects of Recovery Efforts on Products Attitudes (제품태도에 대한 회복노력의 차별적 효과)

  • Kim, Cheon-GIl;Choi, Jung-Mi
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.1
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    • pp.33-58
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    • 2008
  • Previous research has presupposed that the evaluation of consumer who received any recovery after experiencing product failure should be better than the evaluation of consumer who did not receive any recovery. The major purposes of this article are to examine impacts of product defect failures rather than service failures, and to explore effects of recovery on postrecovery product attitudes. First, this article deals with the occurrence of severe and unsevere failure and corresponding service recovery toward tangible products rather than intangible services. Contrary to intangible services, purchase and usage are separable for tangible products. This difference makes it clear that executing an recovery strategy toward tangible products is not plausible right after consumers find out product failures. The consumers may think about backgrounds and causes for the unpleasant events during the time gap between product failure and recovery. The deliberation may dilutes positive effects of recovery efforts. The recovery strategies which are provided to consumers experiencing product failures can be classified into three types. A recovery strategy can be implemented to provide consumers with a new product replacing the old defective product, a complimentary product for free, a discount at the time of the failure incident, or a coupon that can be used on the next visit. This strategy is defined as "a rewarding effort." Meanwhile a product failure may arise in exchange for its benefit. Then the product provider can suggest a detail explanation that the defect is hard to escape since it relates highly to the specific advantage to the product. The strategy may be called as "a strengthening effort." Another possible strategy is to recover negative attitude toward own brand by giving prominence to the disadvantages of a competing brand rather than the advantages of its own brand. The strategy is reflected as "a weakening effort." This paper emphasizes that, in order to confirm its effectiveness, a recovery strategy should be compared to being nothing done in response to the product failure. So the three types of recovery efforts is discussed in comparison to the situation involving no recovery effort. The strengthening strategy is to claim high relatedness of the product failure with another advantage, and expects the two-sidedness to ease consumers' complaints. The weakening strategy is to emphasize non-aversiveness of product failure, even if consumers choose another competitive brand. The two strategies can be effective in restoring to the original state, by providing plausible motives to accept the condition of product failure or by informing consumers of non-responsibility in the failure case. However the two may be less effective strategies than the rewarding strategy, since it tries to take care of the rehabilitation needs of consumers. Especially, the relative effect between the strengthening effort and the weakening effort may differ in terms of the severity of the product failure. A consumer who realizes a highly severe failure is likely to attach importance to the property which caused the failure. This implies that the strengthening effort would be less effective under the condition of high product severity. Meanwhile, the failing property is not diagnostic information in the condition of low failure severity. Consumers would not pay attention to non-diagnostic information, and with which they are not likely to change their attitudes. This implies that the strengthening effort would be more effective under the condition of low product severity. A 2 (product failure severity: high or low) X 4 (recovery strategies: rewarding, strengthening, weakening, or doing nothing) between-subjects design was employed. The particular levels of product failure severity and the types of recovery strategies were determined after a series of expert interviews. The dependent variable was product attitude after the recovery effort was provided. Subjects were 284 consumers who had an experience of cosmetics. Subjects were first given a product failure scenario and were asked to rate the comprehensibility of the failure scenario, the probability of raising complaints against the failure, and the subjective severity of the failure. After a recovery scenario was presented, its comprehensibility and overall evaluation were measured. The subjects assigned to the condition of no recovery effort were exposed to a short news article on the cosmetic industry. Next, subjects answered filler questions: 42 items of the need for cognitive closure and 16 items of need-to-evaluate. In the succeeding page a subject's product attitude was measured on an five-item, six-point scale, and a subject's repurchase intention on an three-item, six-point scale. After demographic variables of age and sex were asked, ten items of the subject's objective knowledge was checked. The results showed that the subjects formed more favorable evaluations after receiving rewarding efforts than after receiving either strengthening or weakening efforts. This is consistent with Hoffman, Kelley, and Rotalsky (1995) in that a tangible service recovery could be more effective that intangible efforts. Strengthening and weakening efforts also were effective compared to no recovery effort. So we found that generally any recovery increased products attitudes. The results hint us that a recovery strategy such as strengthening or weakening efforts, although it does not contain a specific reward, may have an effect on consumers experiencing severe unsatisfaction and strong complaint. Meanwhile, strengthening and weakening efforts were not expected to increase product attitudes under the condition of low severity of product failure. We can conclude that only a physical recovery effort may be recognized favorably as a firm's willingness to recover its fault by consumers experiencing low involvements. Results of the present experiment are explained in terms of the attribution theory. This article has a limitation that it utilized fictitious scenarios. Future research deserves to test a realistic effect of recovery for actual consumers. Recovery involves a direct, firsthand experience of ex-users. Recovery does not apply to non-users. The experience of receiving recovery efforts can be relatively more salient and accessible for the ex-users than for non-users. A recovery effort might be more likely to improve product attitude for the ex-users than for non-users. Also the present experiment did not include consumers who did not have an experience of the products and who did not perceive the occurrence of product failure. For the non-users and the ignorant consumers, the recovery efforts might lead to decreased product attitude and purchase intention. This is because the recovery trials may give an opportunity for them to notice the product failure.

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A study of the plan dosimetic evaluation on the rectal cancer treatment (직장암 치료 시 치료계획에 따른 선량평가 연구)

  • Jeong, Hyun Hak;An, Beom Seok;Kim, Dae Il;Lee, Yang Hoon;Lee, Je hee
    • The Journal of Korean Society for Radiation Therapy
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    • v.28 no.2
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    • pp.171-178
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    • 2016
  • Purpose : In order to minimize the dose of femoral head as an appropriate treatment plan for rectal cancer radiation therapy, we compare and evaluate the usefulness of 3-field 3D conformal radiation therapy(below 3fCRT), which is a universal treatment method, and 5-field 3D conformal radiation therapy(below 5fCRT), and Volumetric Modulated Arc Therapy (VMAT). Materials and Methods : The 10 cases of rectal cancer that treated with 21EX were enrolled. Those cases were planned by Eclipse(Ver. 10.0.42, Varian, USA), PRO3(Progressive Resolution Optimizer 10.0.28) and AAA(Anisotropic Analytic Algorithm Ver. 10.0.28). 3fCRT and 5fCRT plan has $0^{\circ}$, $270^{\circ}$, $90^{\circ}$ and $0^{\circ}$, $95^{\circ}$, $45^{\circ}$, $315^{\circ}$, $265^{\circ}$ gantry angle, respectively. VMAT plan parameters consisted of 15MV coplanar $360^{\circ}$ 1 arac. Treatment prescription was employed delivering 54Gy to recum in 30 fractions. To minimize the dose difference that shows up randomly on optimizing, VMAT plans were optimized and calculated twice, and normalized to the target V100%=95%. The indexes of evaluation are D of Both femoral head and aceta fossa, total MU, H.I.(Homogeneity index) and C.I.(Conformity index) of the PTV. All VMAT plans were verified by gamma test with portal dosimetry using EPID. Results : D of Rt. femoral head was 53.08 Gy, 50.27 Gy, and 30.92 Gy, respectively, in the order of 3fCRT, 5fCRT, and VMAT treatment plan. Likewise, Lt. Femoral head showed average 53.68 Gy, 51.01 Gy and 29.23 Gy in the same order. D of Rt. aceta fossa was 54.86 Gy, 52.40 Gy, 30.37 Gy, respectively, in the order of 3fCRT, 5fCRT, and VMAT treatment plan. Likewise, Lt. Femoral head showed average 53.68 Gy, 51.01 Gy and 29.23 Gy in the same order. The maximum dose of both femoral head and aceta fossa was higher in the order of 3fCRT, 5fCRT, and VMAT treatment plan. C.I. showed the lowest VMAT treatment plan with an average of 1.64, 1.48, and 0.99 in the order of 3fCRT, 5fCRT, and VMAT treatment plan. There was no significant difference on H.I. of the PTV among three plans. Total MU showed that the VMAT treatment plan used 124.4MU and 299MU more than the 3fCRT and 5fCRT treatment plan, respectively. IMRT verification gamma test results for the VMAT plan passed over 90.0% at 2mm/2%. Conclusion : In rectal cancer treatment, the VMAT plan was shown to be advantageous in most of the evaluation indexes compared to the 3D plan, and the dose of the femoral head was greatly reduced. However, because of practical limitations there may be a case where it is difficult to select a VMAT treatment plan. 5fCRT has the advantage of reducing the dose of the femoral head as compared to the existing 3fCRT, without regard to additional problems. Therefore, not only would it extend survival time but the quality of life in general, if hospitals improved radiation therapy efficiency by selecting the treatment plan in accordance with the hospital's situation.

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Shearing Strength Properties of Bolted, Drift-Pinned Joints of the Larix Glulam - Effects of Fastener Diameter, Slenderness and End-distance on Strength Properties - (낙엽송 집성재의 Bolt, Drift Pin 접합부의 전단강도 성능 평가 - 접합구 직경, 세장비, 끝면거리가 강도에 미치는 영향 -)

  • Kim, Keon-Ho;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.1
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    • pp.69-78
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    • 2008
  • Shearing strength test in tension type was investigated to determine the shear resistance of bolt and drift-pin connection of domestic larix glulam. The specimen was connected with bolt and drift-pin in the inserted plate type, and only bolt in the side plate type. The diameter of bolt and drift-pin used in the experiment are 12, 16 and 20 mm. The hole of bolt was drilled at the end-distance 5 d and 7 d. Tension load was loaded in the direction parallel to grain. The shear resistance was evaluated according to end-distance through this, the yield load was compared with the experimental yield load, using Larsen's formula. The prototype design strength is based on the yield load of end-distance 7 d and the reduction factor of end-distance 5 d was calculated. The results were as follows. 1. The average of maximum load of drift-pin connection was higher by 3~30% at the inserted type than at bolt connection with increasing diameter. In bolt connection, the average of maximum load of the side type was 1.54~2.07 times higher than that of the inserted type. In the same diameter, the average of maximum load of end-distance 7 d was higher by 8~44% than that of 5 d. 2. The bearing stress was 1.16~1.41 times higher at the inserted connection than at drift-pin connection, and 1.37~1.86 times higher at 7 d than at 5 d. Also, when the slenderness ratio was below 7.5 at drift-pin connection and below 6.0 at inserted connection, the lateral capacity was good. 3. The ratio of the experimental yield load and the predicted yield load calculated by Larsen's formula proposed by Larsen was 0.80~1.10 at inserted connection, and 0.75~1.46 at side connection. 4. When the inserted bolt connection was based on the yield load of end-distance 7 d, the reduction factor was 0.89 at 12 mm connection, 0.93 at 16 mm and 0.85 at 20 mm. The reduction factor was 0.89 at 12 mm the inserted drift-pin connection, 0.93 at 16 mm, 0.93 at 20 mm. The reduction factor was 0.79 at the side connection of the 12 mm bolt connection and 0.80 at 16 mm.

Reproduction Cycle and Litter Size of Red-tongued viper snake (Gloydius ussuriensis) (쇠살모사의 생식주기와 한배의 출산수)

  • Kim, Byoung-Soo;Oh, Hong-Shik
    • Korean Journal of Environment and Ecology
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    • v.28 no.5
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    • pp.531-541
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    • 2014
  • This research investigated the reproduction cycle, litter size, and the effects of factors of red-tongue viper snake inhabiting in Jeju Island, to delve into their life strategy. Field survey was conducted in Jeju Island from May 2006 to November 2008. Reproduction cycle was analyzed through measurements of testis and follicle sizes in laboratory from March 2009 to December 2010. According to the research results, the sizes of red-tongue viper snake's testis and follicle clearly changed seasonally. The number of eggs within the oviduct were greater on the right side ($2.6{\pm}1.0$ eggs, n=16) than on the left side ($1.8{\pm}0.5$ eggs, n=16) (t=-2,721, p<0.05). Average (${\pm}SD$) of survival litter size (SLS) was $4.4{\pm}1.7$ (1~9, range), while total litter size (TLS) was $4.7{\pm}1.5$ (3~9, range), which were not statistically significant. However, their litter sizes were similar to the number of eggs within the oviduct (t=0.039, P>0.05). Relative litter mass (RCM) was $0.42{\pm}0.13$ (0.18~0.79, n=33), and tended to increase, as maternal condition of pre-parturition (MCPPI) was getting better. The sexual ratio of delivered litters showed no significant difference between male and female red-tongue viper snakes (♂:♀ = 1.15:1, n=73 ; ${\chi}^2$=0.342, P>0.5). Average neonate mass showed a weak correlation with maternal mass of pre-parturition (MMPP1) (r=0.387, P<0.05, n=33). Average neonate Snout-vent length (SVL) also demonstrated a weak correlations with maternal SVL (r=0.399, P<0.05, n=33) and MMPP1 (r=0.344, P<0.05, n=33). Average neonate mass and maternal SVL approached significant probability (r=0.323, P=0.067, n=33). This indicates that mother snakes can bear bigger litter due to its larger size. In some cases, litter's weight decreases as mother snakes are bearing more litter; however, the red-tongued viper snake did not show such exchange relationship. From this, it can be conjectured that a red-tongued viper snake has peculiarity of its own species. The research results are predicted to be used as the basis to find a life history of red-tongued viper snake.