• 천문학회지
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• 제29권spc1호
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• pp.19-21
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• 1996

We apply topological measures of clustering such as percolation and genus curves (PC & GC) and shape statistics to a set of scale free N-body simulations of large scale structure. Both genus and percolation curves evolve with time reflecting growth of non-Gaussianity in the N-body density field. The amplitude of the genus curve decreases with epoch due to non-linear mode coupling, the decrease being more noticeable for spectra with small scale power. Plotted against the filling factor GC shows very little evolution - a surprising result, since the percolation curve shows significant evolution for the same data. Our results indicate that both PC and GC could be used to discriminate between rival models of structure formation and the analysis of CMB maps. Using shape sensitive statistics we find that there is a strong tendency for objects in our simulations to be filament-like, the degree of filamentarity increasing with epoch.

• International Journal of Oral Biology
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• 제36권3호
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• pp.123-128
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• 2011

The notion that dental amalgam is a potential source of mercury exposure remains a controversial issue. However, there are few epidemiological analyses that have addressed whether this occurs in children. We aimed in our current study to identify the relationship between dental amalgam filling surfaces and the blood mercury levels in a cohort of 711 South Korean children aged between 8-9 years. Oral examinations were conducted to detect the number of amalgam filling surfaces on the teeth of these individuals. Blood samples were also taken from these children to assess the levels of mercury accumulation in the body. The amalgam filling surfaces were classified into four groups based on their number: 0 (n = 368), 1-5 (n = 219), 6-10 (n = 89), and 11+ (n = 35). The blood mercury levels in the children with more than 10 amalgam surfaces was 0.47 ${\mu}g$/L higher on average than those with no amalgam surfaces after adjusting for the frequency of fish or seafood consumption, age, and gender (P < 0.05). We found from our data that a higher number of dental amalgam fillings correlated with a higher blood mercury level in Korean children. Further studies are needed to investigate whether these elevated mercury levels exert neurotoxic or nephrotoxic effects.

• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.5.1-5.22
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• 2023

This systematic review and network meta-analysis aimed to answer the following focused research question: "Does the type of endodontic sealer affect the postoperative pain in patients who received endodontic treatment?" Different databases and grey literature were surveyed. Only one randomized controlled trial were included. The risk of bias in the studies was evaluated by using the Cochrane Collaboration's tool. A random-effects meta-analysis was conducted to compare the risk and intensity of postoperative pain. The quality of the body of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Out of 11,601 studies, 15 remained for qualitative analyses and 12 for meta-analysis. Seven studies were classified at high risk of bias, and 8 studies raised some concerns. No significant differences between the endodontic materials were observed in the direct comparisons, both in risk and in intensity of postoperative pain (pairwise comparisons with 2 studies: I² = 0%; p > 0.05 and 8 studies: I² = 23%; p > 0.05, respectively). The certainty of the evidence was graded as low or moderate. There was no difference in the risk and intensity of postoperative pain after filling with different endodontic sealers. Further systematic reviews should be conducted.

• Human Ecology Research
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• 제62권2호
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• pp.317-326
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• 2024

This study evaluated the thermal physiological and psychological responses elicited when wearing cold protective jackets with aerogel fillings in two cold environments, one without air velocities and one with air velocities (2.3 m·s-1), at an air temperature of 10℃. The participants were five healthy young males. Measures were taken of physiological parameters, blood pressure (BP), heart rate (HR), core temperature, oxygen uptake (Vo2), and microclimate (temperature and humidity). The psychological parameters evaluated were thermal and wetness sensation. No differences were observed in systolic blood pressure, heart rate, and oxygen intake between the conditions. At tympanic temperature, a significant difference was observed between the conditions during exercise (p<.05); . A significant difference was observed in the microclimate temperature of the clothing according to the airflow, and temperature changes in the chest and back revealed different patterns. Significant differences were observed in thermal sensation (whole body (p<.05), chest (p<.05), back (p<.01)) between airflow conditions. The results therefore indicate that cold protective jackets with an aerogel filling are suitable for people operating in low-temperature and airflow environments.

• 대한기계학회논문집A
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• 제24권10호
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• pp.2610-2618
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• 2000

In this paper, the elastic deformation of cold forging die has been investigated to improve the accuracy of forged parts with FEM analysis and experiments using the strain gages. In the finite element analysis, two types of analysis are used to predict elastic deformation of die. The one is that dies are considered to be elastic body from initial stage to final one, and the other is that the dies are considered to be rigid body during forging simulation and then considered to be elastic body at elastic analysis. Considering the results of analysis and experiments, it is likely that the analytical results are in good agreement with experimental inspections. The method using the elastic assumption of die relatively takes a lot of time to simulate the forming operation. However, It is better that using an elastic die to predict not only the shape of product but also filling of die cavity.

• 대한치과기공학회지
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• 제45권3호
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• pp.81-86
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• 2023

Purpose: This study aimed to observe the effect of laminate veneer on patient's teeth based on the manufacturing of laminate veneer restorations, which are produced by fabricating a ceramic cast body using IPS Empress, a pressure casting method and then forming the veneer by layering. Subsequently, we assessed the potential of its clinical application. Methods: This study discusses and preserves various treatment plans, such as diagnostic wax-up and treatment room diagnosis, for patients who visit the hospital to improve the appearance of teeth due to diastema of maxillary teeth, inexperienced resin filling, lack of esthetics, and external teeth. A ceramic cast body is constructed using IPS Empress, which is an effective and aesthetic restoration pressure casting method to restore the veneer with a laminate made by layering. Results: Compared with the preoperative state, the frontal view of the patient after the final restoration showed the formation of a natural smile line; the space between the central and lateral incisors was filled in synchronously with the adjacent teeth. In addition, the emergence profile is maintained by reducing the over-contour as much as possible. Conclusion: The patient's quality of life is improved by providing them with a satisfactory natural smile.

• Clinical and Experimental Pediatrics
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• 제57권5호
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• pp.232-239
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• 2014

Purpose: Mitochondrial disease (MD) and Duchenne muscular dystrophy (DMD) are often associated with cardiomyopathy, but the myocardial variability has not been isolated to a specific characteristic. We evaluated the left ventricular (LV) mass by echocardiography to identify the general distribution and functional changes of the myocardium in patients with MD or DMD. Methods: We retrospectively evaluated the echocardiographic data of 90 children with MD and 42 with DMD. Using two-dimensional echocardiography, including time-motion (M) mode and Doppler measurements, we estimated the LV mass, ratio of early to late mitral filling velocities (E/A), ratio of early mitral filling velocity to early diastolic mitral annular velocity (E/Ea), stroke volume, and cardiac output. A "z score" was generated using the lambda-mu-sigma method to standardize the LV mass with respect to body size. Results: The LV mass-for-height z scores were significantly below normal in children with MD ($-1.02{\pm}1.52$, P<0.001) or DMD ($-0.82{\pm}1.61$, P =0.002), as were the LV mass-for-lean body-mass z scores. The body mass index (BMI)-for-age z scores were far below normal and were directly proportional to the LV mass-for-height z scores in both patients with MD (R =0.377, P<0.001) and those with DMD (R =0.330, P=0.033). The LV mass-for-height z score correlated positively with the stroke volume index (R =0.462, P<0.001) and cardiac index (R =0.358, P<0.001). Conclusion: LV myocardial atrophy is present in patients with MD and those with DMD and may be closely associated with low BMI. The insufficient LV mass for body size might indicate deterioration of systolic function in these patients.

• 한국방사선학회논문지
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• 제14권5호
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• pp.651-660
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• 2020

본 연구에서는 보급형 3D 프린터를 이용하여 인체 Femur와 유사한 HU 값을 가진 팬텀을 제작하여 기존 돼지 뼈를 대체할 수 있는지 분석하고자 하였다. 인체 Femur의 HU 값을 알아보기 위해 연령별 총 372명의 데이터를 분석하였다. 보급형 3D 프린터를 이용하여 PLA-Cu 20%를 이용하여 인체 뼈 모형 팬텀을 제작하여 CT 검사하였다. 돼지 뼈는 생후 6개월 된 돼지로 도축된 지 2일이 지난 뼈를 이용하였다. 검사결과 내부채움 80%로 제작한 3D 프린팅 팬텀이 인체의 모든 데이터와 유사한 값이 나타났고(p<0.05) 돼지뼈와는 차이가 있었다(p>0.05). 또한 연령대별 Femur의 HU 값의 경우 연령대가 증가할수록 HU의 값은 줄어드는 것으로 확인 되었다(p<0.05). 3D 프린팅과 HU 값은 적층 높이에 대해서는 약한 음의 상관성을 확인 하였지만 내부 채움에서는 182.13±1.290으로 강한 양의 상관성(R²=0.996)을 확인하였다(p<0.05). 결론적으로 3D 프린팅을 이용한 인체 모형 팬텀이 기존 돼지뼈 팬텀에 비해 인체와 유사한 정도의 HU 값을 나타낼 수 있음을 확인할 수 있었으며 이에 본 연구가 3D 프린터를 이용한 인체 모형 팬텀의 제작에 기초자료를 제공할 수 있을 것이라 사료된다.

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5299-5304
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• 2012

인체는 공기, 지방, 근육, 뼈, 혈관과 같이 서로 다른 조직으로 구성되어 있어 각 조직간 자화율 차이로 인해 자장의 불균일이 항상 발생하여 신호가 감소한다. 이에 본 연구에서는 서로 다른 조직으로 구성된 인체의 신호감소를 해결하기 위하여 인체의 조직밀도와 유사한 실리콘을 이용하여 공기와 맞닿은 굴곡진 부분에 보상함으로써 자기공명영상의 신호를 높이고자 하였다. 특별한 증상이 없는 성인 8명으로 대상으로 하였으며, 인체 중 굴곡이 많고 구조가 복잡해 신호감소가 많이 발생하는 발을 설정하였다. 영상은 종족궁의 가운데부터 5개의 말절골을 포함하여 얻었으며, 중족골 및 족지골을 연장한 선에 평행하게 30절편을 얻었다. 측정은 실리콘의 적용 전 후 뼈와 연부조직의 SNR을 비교하였으며, 대응표본 T검정을 이용하여 통계분석 하였다. 연구결과 뼈와 연부조직의 T1, T2 강조영상 모두 실리콘 적용 후가 적용 전에 비해 SNR이 월등히 높게 나왔으며 유의한 양의 상관관계로 증가하였다. 결론적으로 본 연구는 체적소에 영향을 주지 않으면서 코일내 인체의 부피를 늘린 획기적인 개선 방법으로, 본질적 문제인 체적소의 부피나 균일성 저하를 해결하여 SNR을 높일 수 있었다.

• 대한가정학회지
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• 제39권8호
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• pp.137-154
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• 2001

This study was made to draft the tight fitting bodice pattern which horizontal and perpendicular stands are to be lightly set, with the consideration of characteristics of body shape in design of clothes. Measurement of body was conducted on 53 women in twenties, and observation was made on surface development pattern by adhesive tape addition method and gypsum method on three standard objects. In the study, bodice pattern was completed by using already made Somato- measurer, compared with existing bodice pattern, and the results are as follows. The result of the correlation analysis by body measurement shows that chest circumference has a relation to B$.$P-front neck point, side neck point, shoulder point, front interscye breadth point, and the item in spine scapulae point has relation to the item of back neck line, and front & back horizontal values. The degree of shoulder slant, width of armhole and of its depth, the amount of breast, back space, back length were shown to be directly measured from the body. In surface development pattern, tight-fit bodice pattern necessary to the breast volume and back space were shown to be investigated and these volume have to be given in setting up basic line for clothes design together with body measurement value. The result of sensory evaluation for appearance test on fitness shows higher value of research bodice including line of shoulder line, front and back interscye breadth, chest circumference, waist circumference, armhole circumference and of its depth, compared with the research bodice in most items. The result of this study is seen showing high effectiveness for the basic data to design the ready-made dress of high sensitivity of high value added tat.