• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.193-198
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• 2010

In solid propellant rocket motors, $Al_2O_3$, one of combustion products, can be accumulated inside a combustion chamber. A special rocket motor was designed and tested to simulate thermal reaction of rubber insulator affected by the deposited slag. We successfully demonstrated through a dynamic radioscopy that the slag was deposited at the location as designed. In this paper we present a new test method which can simulate a high temperature and pressure environment in combustion chamber to evaluate material characteristics of rubber insulator and can provide design data to decide its thickness for a new solid rocket motor. The solid rocket motor, which has an average chamber pressure of 770 psia and a burning time of 50 seconds, was tested. The results show that erosion of EPDM insulator is more affected by a gas velocity rather than by the thermal reaction of slag with a high thermal capacity.

• Advances in Traditional Medicine
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• v.9 no.2
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• pp.106-114
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• 2009

Hepatocellular carcinoma is the world's most common primary malignant tumor of the liver. In-Jin-ho-Tang (IJHT) has been used as a traditional Chinese herbal medicine since ancient times, and today it is widely used as a medication for jaundice associated with inflammation of the liver. In-Jin-Ho-Tang is a drug preparation consisting of three herbs: Artemisiae Capillaris Herba (Artemisia capillaries $T_{HUNS}$, Injinho in Korean), Gardeniae Fructus (Gardenia jasminodes $E_{LLIS}$, Chija in Korean) and Rhei radix et rhizoma (Rheum palmatum L., Daehwang in Korean). This study investigated whether or not methanol extract of IJHT could induce HepG2 cancer cell death. Cytotoxic activity of IJHT on HepG2 cells was measured using an XTT assay, with an $IC_{50}$ value of $700{\mu}g/ml$ at 24 h Apoptosis induction by IJHT in HepG2 cells was verified by the cleavage of poly ADP-ribose polymerase, and a decrease in procaspase-3, -8, -9. Treatment of IJHT resulted in the release of cytochrome c into cytosol, loss of mitochondrial membrane potential (${\Delta}{\Psi}_m$), decrease in anti-apoptotic Bcl-2, and an increase in pro-apoptotic Bax expression. Thus, IJHT induced apoptosis in HepG2 cells via activation of caspase and mitochondria pathway. These results indicate that IJHT has potential as an anti-cancer agent.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.22 no.4
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• pp.228-235
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• 2011

Objectives : This study was conducted to compare the object relations and parenting behavior of the mothers of children with attention-deficit hyperactivity disorder (ADHD) with that of the mothers with normal children. Methods : In this study, we studied 64 mothers of children who were diagnosed with ADHD and 90 mothers of normal children. The mothers completed the Bell Object Relations Inventory (BORI), the Parenting Behavior Inventory (PBI), the Parenting Stress Index (PSI) and the Parenting Sense of Competence (PSOC) scale. Results : As compared with the mothers of normal children, the mothers of children with ADHD showed significantly different results for the parenting stress and parenting efficacy. For parenting behavior, the mothers of children with ADHD perceived their mothering as being more neglectful. On the other hand, the mothers of the normal control group perceived their mothering as being more affectionate and the fathers as being more reasonable and monitoring. Conclusion : This study suggests there is a significant difference of object relation between the mothers of children with ADHD and the mothers with normal children. The object relation pathology of the mothers of children with ADHD might contribute to impaired parenting behavior. The result of the present study indicate that inadequate grandparental rearing behavior affects the insecure object relation of their child (the mother), and a mother's insecure object relation affects their parental stress and parenting efficacy.

• Child Health Nursing Research
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• v.12 no.3
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• pp.314-321
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• 2006

Purpose: The purposes of this descriptive survey study were to describe postpartum depression level and to identify the influence of postpartum depression on maternal role confidence, parenting stress and infant temperament, in order to develop a base for nursing intervention programs for mothers who have postpartum depression. Method: Data were collected from 183 mothers of infants who visited one public health center in Goyang city. The instrument used for this study was a self-report questionnaire to identify the postpartum depression (BDI), maternal role confidence, parenting stress (PSI) and infant temperament (WBL). Results: Of the mothers 42.1% were in the normal range for postpartum depression, 33.3% in the mild group and 24.6% were in the moderate to severe group. There were significant differences in parenting stress, and infant temperament according to level of postpartum depression. There were correlations between maternal role confidence (r=-0.13), infant temperament (r=-0.20), parenting stress (r=0.51) and postpartum depression, and weak negative correlation between parenting stress and infant temperament (r=-0.30). Conclusion: Postpartum depression in the infant period when the mother's role is very important and the effect is not only on the mother's role but also on the infant's growth. It is essential to assess and provide immediate care to mothers who have postpartum depression.

• Physical Therapy Korea
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• v.4 no.3
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• pp.34-44
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• 1997

The purpose of this study was to compare the balance ability at different foot angle with KAT 2000 (Breg, Inc., Vista, CA. 1994). Forty-nine (male 24, female 25) normal subjects participated in this study. All subjects were assessed under two conditions. One was eye-opened condition and the other one was eye-closed one in 3 psi surface condition. All subjects were tested at different foot angle that were toe-in $25^{\circ}$, $45^{\circ}$, toe-out $25^{\circ}$ and $45^{\circ}$. The subject attempted to keep the platform as stable as possible with eyes closed and with eyes opened for every 20 seconds. The starting position was that subject crossed their arms across chest and flexed knees slightly. The results of each test were showed by a score on screen, which meant balance index. The se collected data were analyzed by using oneway ANOVA, Scheffe test, and t-test. The results of this study were as follows: 1. When the foot angle were changed, balance index was the lowest in toes-out $25^{\circ}$ condition and greatest with toes-in $45^{\circ}$ with eyes opened and with eyes closed. There were statistically significant difference with eyes opened and with eyes closed (p<0.05). 2. There was statistically significant difference in balance index according to visual condition and the balance index tested with eyes closed was higher than with eyes closed(p<0.05). 3. There was statistically significant difference in balance index by gender(p<0.05).

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1449-1459
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• 2009

Coptidis rhizoma (huanglian) is an herb that is widely used in traditional Chinese medicine that has recently been shown to possess anticancer activity. However, the molecular mechanism underlying the anticancer effects of this herb is poorly understood. In this study, we investigated the anticancer activity of a combination of CR extract and arsenic trioxide, as well as the apoptotic pathway associated with its mechanism of action in human lung cancer H157 cells. Combined treatment of H157 cells with CR extract and arsenic trioxide resulted in significant apoptotic death. In addition, combined treatment with CR extract and arsenic trioxide acted in concert to induce a loss of mitochondrial membrane potential (${\Delta}{\Psi}$), the release of cytochrome c from mitochondria, and an increase in the expression of pro-apoptotic p53 and Bax protein, which resulted in activation of caspases and apoptosis. CR extract combined with arsenic trioxide also increased the lipid peroxidation, mRNA expression of DR4 and DR5 and caspase-8 activity. These data indicate that combined treatment with CR extract and arsenic trioxide enhanced apoptotic cell death in H157 cells through diverse pathways, including mitochondrial dysfunction and death receptors, particularly DR4 and DR5. Thus, this treatment may be an effective from of chemotherapy.

• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.210-216
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• 2015

BACKGROUND: In korea, sweet persimmon(Diospyros kaki) cultivation is front to abiotic stresses such as frost damage at fruit maturing stage. The cold and rapid freezing stresses are most damaging to fruit production which is most actively progressed in late fall. This study was performed to evaluate the validity of chlorophyll fluorescence imaging(CFI) technology to determine the degree of frost damage in sweet persimmon fruits. METHODS AND RESULTS: The sweet persimmon fruits were measured separately for each treatment(15, 30, 60 minutes) at 24 hours after treatment(HAT) rapid freezing. A CFI FluorCam (FC 1000-H, PSI, Czech Republic) was used to measure the fluorescence images of the fruits. In rapid freezing for 15 minutes, photochemical parameters were not changed. However, in rapid freezing for 30 and 60 minutes, photochemical parameters were lowered. Especially, $F_m$, $F_v$, $F_v/F_m$ and ${\Phi}PSII$ values were declined under rapid freezing. CONCLUSION: In our study, it was clearly indicated that the rapid freezing could be a stress in sweet persimmon fruits. The CFI analysis and its related parameters are applicable as a rapid assessing technique for the determination of frost damage.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.4
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• pp.373-382
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• 2015

Fura-2 analogs are ratiometric fluoroprobes that are widely used for the quantitative measurement of [$Ca^{2+}$]. However, the dye usage is intrinsically limited, as the dyes require ultraviolet (UV) excitation, which can also generate great interference, mainly from nicotinamide adenine dinucleotide (NADH) autofluorescence. Specifically, this limitation causes serious problems for the quantitative measurement of mitochondrial [$Ca^{2+}$], as no available ratiometric dyes are excited in the visible range. Thus, NADH interference cannot be avoided during quantitative measurement of [$Ca^{2+}$] because the majority of NADH is located in the mitochondria. The emission intensity ratio of two different excitation wavelengths must be constant when the fluorescent dye concentration is the same. In accordance with this principle, we developed a novel online method that corrected NADH and Fura-2-FF interference. We simultaneously measured multiple parameters, including NADH, [$Ca^{2+}$], and pH/mitochondrial membrane potential; Fura-2-FF for mitochondrial [$Ca^{2+}$] and TMRE for ${\Psi}_m$ or carboxy-SNARF-1 for pH were used. With this novel method, we found that the resting mitochondrial [$Ca^{2+}$] concentration was $1.03{\mu}M$. This $1{\mu}M$ cytosolic $Ca^{2+}$ could theoretically increase to more than 100 mM in mitochondria. However, the mitochondrial [$Ca^{2+}$] increase was limited to ${\sim}30{\mu}M$ in the presence of $1{\mu}M$ cytosolic $Ca^{2+}$. Our method solved the problem of NADH signal contamination during the use of Fura-2 analogs, and therefore the method may be useful when NADH interference is expected.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1563-1570
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• 2015

Conformational change during chain propagation of alanine oligomer was investigated by quantum chemical calculation(QCC) using 2~5mers(${\times}=2{\sim}5$) models. For estimation of the end group effects, two types of end group. "amide type" ($CH_3CONH-and-CONHCH_3$) and "methyl type" ($CH_3CONH-and-CONHCH_3$), were prepared as both ends(N-and-C). Conformers optimized for 5-mer converged to three types of ${\Phi}/{\Psi}$ : ${\alpha}$-helix(g+/g+, or g-/g-), PPII-like(extended helix-like, g+/g-, or g-/g+), and ${\beta}$-extended (t+/t-, or t-/t+), in the order of lower energy, and the energies of left- and right- handed conformers were the same (5-mer. amide type ${\Delta}E=-1.05$, right type ${\Delta}E=-1.62$). Energies of the monomer unit(${\Delta}E$) of ${\alpha}$-helix decreased with increases of monomer.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.69-69
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• 2000

(Ba, Sr)TiO3 (BST)[1-3] 박막은 유전상수가 크고 고주파에서도 유전특성 저하가 적기 때문에 ULSI DRAM(Dynamic Random Access Memory)에 응용 가능한 물질로 최근 각광을 받고 있다. 하지만, 아직 BST 박막을 DRSM에 바로 적용하기 위해선 몇 가지 문제점이 있다. 그 중 누설전류 문제는 디바이스 응용시 매우 중요한 요소이다. 특히, DRAM에서 refresh time와 직접적인 관련이 있어 디바이스 내의 신뢰도 및 전력소모를 결정하는 주된 인자가 된다. 지금까지, BST 박막의 인가전업, 온도, 그리고 전극물질에 따른 누설전류 현상들이 고찰되었고, 이에 관한 많은 전도기구 모델들이 제시되었다. Schottky emission, Poole-Frenkel emission, space charge limited conduction 등이 그 대표적인 예이다. 하지만 아쉽게도 BST 박막의 정확한 누설 전류 전도 기구를 완전히 설명하는데는 아직 한계가 있다. 따라서 본 연구에서는 제작된 BST 커패시터 내의 기본적인 전기적 성질을 조사하고, 정확한 누설전류 기구 규명에 초점을 두고자 한다. 이를 위해 기존의 여러 기구들과 비교 분석할 것이다. 하부전극으로 사용하기 위해 스퍼터링 방법으로 p-Si(100) 기판위에 RuO2 박막을 약 120nm 증착하였다. 증착전의 chamberso의 초기압력은 5$\times$10-6 Torr이하의 압력으로 유지시켰다. Ar/O2의 비는 이전 실험에서 최적화된 9/1로 하였다. BST 박막 증착 시 5분간 pre-sputtering을 실시한 후 하부전극 기판위에 BST 박막을 증착하였다. 증착이 끝난 후 시편을 상온까지 냉각시킨 후 꺼내었다. 전기적 특성을 측정하기 상부전극으로 RuO2와 Al 박막을 각각 상온에서 100nm 증착하였다. 이때 hole mask를 이용하여 반경이 140um인 원형의 상부전극을 증착하였다. BST 박막의 증착온도가 증가하고 Ar/O2 비가 감소할수록 제작된 BST-커패시터의 전기적 성질이 우수하였다. 증착온도 $600^{\circ}C$, ASr/O2=5/5에서 증착된 막의 누설전류는 4.56$\times$10-8 A/cm2, 유전상수는 600 정도의 값을 나타내었다. 인가전압에 따른 BST 커패시터의 transition-current는 Curie-von Schweider 모델을 따랐다. BST 박막의 누설전류 전도기구는 기존의 Schottky 모델이 아니라 modified-Schottky 무델로 잘 설명되었다. Modified-Schottky 모델을 통해 BST 박막의 광학적 유전율 $\varepsilon$$\infty$=4.9, 이동도 $\mu$=0.019 cm2/V-s, 장벽 높이 $\psi$b=0.79 eV를 구하였다.