• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4698-4707
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• 2022

As part of the ICRP Task Group 103 project, we developed ten thyroid models for the pediatric mesh-type reference computational phantoms (MRCPs). The thyroid is not only a radiosensitive target organ needed for effective dose calculation but an important source region particularly for radioactive iodines. The thyroid models for the pediatric MRCPs were constructed by converting those of the pediatric voxel-type reference computational phantoms (VRCPs) in ICRP Publication 143 to a high-quality mesh format, faithfully maintaining their original topology. At the same time, we improved several anatomical parameters of the thyroid models for the pediatric MRCPs, including the mass, overlying tissue thickness, location, and isthmus dimensions. Absorbed doses to the thyroid for the pediatric MRCPs for photon external exposures were calculated and compared with those of the pediatric VRCPs, finding that the differences between the MRCPs and VRCPs were not significant except for very low energies (<0.03 MeV). Specific absorbed fractions (target ⟵ thyroid) for photon internal exposures were also compared, where significant differences were frequently observed especially for the target organs/tissues close to the thyroid (e.g., a factor of ~1.2-~327 for the thymus as a target) due mainly to anatomical improvement of the MRCP thyroid models.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2002년도 춘계학술대회 논문집
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• pp.433-445
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• 2002

본 연구는 전자정부의 실현을 위한 전자세정분야 가운데 정부와 고객(G2C)간의 비즈니스 유형으로 지방세의 전자납부제에 대한 현황을 고찰하고 이에 대한 활성화 방안을 제시하였다. 본 연구의 조사는 우리나라 232개 시군구의 지방자치단체의 담당자를 대상으로 면접조사와 더 불어 C군의 전자납부제 이용자를 대상으로 설문에 의한 전수조사를 실시하였다. 본 연구의 결과, 지방세 전자납부제는 전국적으로 196개의 시군이 도입운영 하고 있으나 지역별로 많은 차이를 보이고 있다. 또한, 전자납부제 운영 시스템에 있어서도 다양한 방식으로 운영되고 있으며, 이용연령층은 30대가 대부분을 차지하고 있었다. 요약컨대, 납세자의 연령층, 지역간의 이질성 시스템과 같은 인프라등에서 정보격 차가 매우 심각한 것으로 나타났다. 그러나 이용자들이 지방세 전자납부제에 대하여 긍정적으로 평가하고 있어서 앞으로 이 제도가 새로운 납부제도로 정착될 것으로 기대된다. 지방세 전자납부제의 활성화 방안으로 전자납부제 이용자에 대한 인센티브 부여, 전자납부방식에 의한 시용카드납부제 실시, 지방세 전자납부제 운영 시스템의 개선, 그리고 납세자 지식 정보화 교육의 강화등을 들 수 있다. 앞으로 전자정부실현을 위한 일환으로 추진하고 있는 지방세 전자납부제에 관한 좀 더 체계적이고 과학적인 접근을 통해 이 분야에 대한 심도있는 연구가 기대된다.

• Tuberculosis and Respiratory Diseases
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• 제77권2호
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• pp.65-72
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• 2014

Background: It is valuable to find the potential activity of regulating the excessive mucin secretion by the compounds derived from various medicinal plants. We investigated whether aqueous extract of the root bark of Morus alba L. (AMA), kuwanon E, kuwanon G, mulberrofuran G, and morusin significantly affect the secretion and production of airway mucin using in vivo and in vitro experimental models. Methods: Effect of AMA was examined on hypersecretion of airway mucin in sulfur dioxide-induced acute bronchitis in rats. Confluent NCI-H292 cells were pretreated with ethanolic extract, kuwanon E, kuwanon G, mulberrofuran G, or morusin for 30 minutes and then stimulated with phorbol 12-myristate 13-acetate (PMA) for 24 hours. The MUC5AC mucin secretion and production were measured by enzyme-linked immunosorbent assay. Results: AMA stimulated the secretion of airway mucin in sulfur dioxide-induced bronchitis rat model; aqueous extract, ethanolic extract, kuwanon E, kuwanon G, mulberrofuran G and morusin inhibited the production of MUC5AC mucin induced by PMA from NCI-H292 cells, respectively. Conclusion: These results suggest that extract of the root bark and the natural products derived from Morus alba L. can regulate the secretion and production of airway mucin and, at least in part, explains the folk use of extract of Morus alba L. as mucoregulators in diverse inflammatory pulmonary diseases.

• Archives of Pharmacal Research
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• 제26권3호
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• pp.232-236
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• 2003

Elsholtzia splendens Nakai has been used in North-East Asia as an ingredient of folk medicines for treating cough, headache and inflammation. The present investigation was carried out to establish its in vivo anti-inflammatory activity using several animal models of inflammation and pain. The 75% ethanol extract of the aerial part of E. splendens significantly inhibited mouse croton oil-induced, as well as arachidonic acid-induced, ear edema by oral administration (44.6% inhibition of croton oil-induced edema at 400 mg/kg). This plant material also showed significant inhibitory activity against the mouse ear edema induced by multiple treatment of phorbol ester for 3 days, which is an animal model of subchronic inflammation. In addition, E. splendens exhibited significant analgesic activity against mouse acetic acid-induced writhing (50% inhibition at 400 mg/kg), while indomethacin (5 mg/kg) demonstrated 95% inhibition. E. splendens ($5-100{\;}{\mu}g/mL$) significantly inhibited $PGE_2$ production by pre-induced cyclooxygenase-2 of lipopolysaccharide-treated RAW 264.7 cells, suggesting that cyclooxygenase-2 inhibition might be one of the cellular mechanisms of anti-inflammation.

• Carbon letters
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• 제11권3호
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• pp.224-234
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• 2010

Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by $N_2$-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 $m^2/g$, total pore volume of 0.423 $cm^3/g$ and average pore diameter of 17.8 ${\AA}$. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.

• Journal of Nutrition and Health
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• 제26권3호
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• pp.338-346
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• 1993

The purpose of this study was to examine nutrient intakes, food and daily habits, and serum lipids for female college students. The subjects consisted of 70 female college students aged 20 to 29 years old. Their dietary intakes were assessed by means of 24 hour dietary recall method. Food models and other measuring tools were also used. Concentrations of serum lipids were measured. The energy intake of the subjects averaged 1837Kcal, whereas the expended energy was 1871Kcal. The subjects consumed 310g of carbohydrates, 66g protien, 37g lipid, 14mg iron, 586mg calcium, 513R.E. vitamin A, 1.0mg vitamin B1, 1.3mg vitamin B2 1.5mg niacin, and 69mg vitamin C, respectively. Vitamin A and iron intakes were lower than the RDA. The percentages of total calorie from carbohydrate, fat, and protein were 67%, 18%, 14%, showing desirable calorie construction. The mean serum triglyceride(TG), cholesterol (Chol), HDL-Chol and LDC-Chol concentrations were 72.4mg/dl, 161.3mg/dl, 44.5mg/dl, and 102.3mg/dl, respectively. All of these values seem to fall in the desirable range. There were positive correlations between serum Chol and HDL-Chol or LDL-Chol or TG ; negative correlations between serum Chol and HDL-Chol/LDL-Chol ratio, between serum TG and HDL-Chol or HDL-Chol/LDC-Chol ratio.

• 한국과학교육학회지
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• 제36권3호
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• pp.389-397
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• 2016

이 연구는 기계 번역을 활용하여 영어기반서술형 평가의 자동채점모델을 한국어 응답에 적용하는 방법의 효용감을 조사하기 위하여 이루어졌다. 이 연구를 위하여 예비생물교사 128명이 4문항으로 구성된 자연선택개념평가도구에 응답한 512개의 서술형응답을 활용하였다. 서술형응답은 한글맞춤법을 교정한 것과 교정하지 않은 학생들이 작성한 그대로의 응답 두 가지를 구글번역으로 번역하였다. 8가지 과학적 개념과 비과학적 개념을 채점하는 자동채점모델을 통해 생성한 4096개의 예측자료의 정확도를 독립적으로 수행한 전문가 채점자료와 비교하는 방법으로 확인하였다. 그 결과 컴퓨터로 채점한 점수와 전문가 채점점수의 평균값의 문항별 분포는 유의미한 차이가 없었다. 평균값을 활용하여 생성한 통계치들은 전문가 채점자료를 통하여 생성한 자료들과 유의미한 차이가 없었다. 학생별 점수의 Pearson 상관관계 계수를 확인한 결과 과학적 개념 점수는 0.848, 비과학적 개념 점수는 0.776이었다. 언어적으로 단순한 개념의 경우 채점자간 일치도 (kappa)가 0.8이상이었다. 이 결과는 기계 번역과 영어기반 서술형 평가의 자동채점모델이 우리나라 학생들의 자연선택개념문항을 채점하는데 유용한 방법이 될 수 있음을 보여준다.

• Imaging Science in Dentistry
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• 제42권3호
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• pp.163-167
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• 2012

Purpose: ANSI/ADA has established standards for adequate radiopacity. This study was aimed to assess the changes in radiopacity of composite resins according to various tube-target distances and exposure times. Materials and Methods: Five 1-mm thick samples of Filtek P60 and Clearfil composite resins were prepared and exposed with six tube-target distance/exposure time setups (i.e., 40 cm, 0.2 seconds; 30 cm, 0.2 seconds; 30 cm, 0.16 seconds, 30 cm, 0.12 seconds; 15 cm, 0.2 seconds; 15 cm, 0.12 seconds) performing at 70 kVp and 7 mA along with a 12-step aluminum stepwedge (1 mm incremental steps) using a PSP digital sensor. Thereafter, the radiopacities measured with Digora for Windows software 2.5 were converted to absorbencies (i.e., A=-log (1-G/255)), where A is the absorbency and G is the measured gray scale). Furthermore, the linear regression model of aluminum thickness and absorbency was developed and used to convert the radiopacity of dental materials to the equivalent aluminum thickness. In addition, all calculations were compared with those obtained from a modified 3-step stepwedge (i.e., using data for the 2nd, 5th, and 8th steps). Results: The radiopacities of the composite resins differed significantly with various setups (p<0.001) and between the materials (p<0.001). The best predicted model was obtained for the 30 cm 0.2 seconds setup ($R^2$=0.999). Data from the reduced modified stepwedge was remarkable and comparable with the 12-step stepwedge. Conclusion: Within the limits of the present study, our findings support that various setups might influence the radiopacity of dental materials on digital radiographs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권2호
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• pp.683-701
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• 2012

IEEE 802.11 standard has achieved huge success in the past decade and is still under development to provide higher physical data rate and better quality of service (QoS). An important problem for the development and optimization of IEEE 802.11 networks is the modeling of the MAC layer channel access protocol. Although there are already many theoretic analysis for the 802.11 MAC protocol in the literature, most of the models focus on the saturated traffic and assume infinite buffer at the MAC layer. In this paper we develop a unified analytical model for IEEE 802.11 MAC protocol in ad hoc networks. The impacts of channel access parameters, traffic rate and buffer size at the MAC layer are modeled with the assistance of a generalized Markov chain and an M/G/1/K queue model. The performance of throughput, packet delivery delay and dropping probability can be achieved. Extensive simulations show the analytical model is highly accurate. From the analytical model it is shown that for practical buffer configuration (e.g. buffer size larger than one), we can maximize the total throughput and reduce the packet blocking probability (due to limited buffer size) and the average queuing delay to zero by effectively controlling the offered load. The average MAC layer service delay as well as its standard deviation, is also much lower than that in saturated conditions and has an upper bound. It is also observed that the optimal load is very close to the maximum achievable throughput regardless of the number of stations or buffer size. Moreover, the model is scalable for performance analysis of 802.11e in unsaturated conditions and 802.11 ad hoc networks with heterogenous traffic flows.

• BMB Reports
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• 제46권10호
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• pp.513-518
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• 2013

We investigated the protective effects of Gymnaster koraiensis against oxidative stress-induced hepatic cell damage. We used two different cytotoxicity models, i.e., the administration of tert-butyl hydroperoxide (t-BHP) and acetaminophen, in HepG2 cells to evaluate the protective effects of G. koraiensis. The ethyl acetate (EA) fraction of G. koraiensis and its major compound, 3,5-di-O-caffeoylquinic acid (DCQA), exerted protective effects in the t-BHP-induced liver cytotoxicity model. The EA fraction and DCQA ameliorated t-BHP-induced reductions in GSH levels and exhibited free radical scavenging activity. The EA fraction and DCQA also significantly reduced t-BHP-induced DNA damage in HepG2 cells. Furthermore, the hexane fraction of G. koraiensis and its major compound, gymnasterkoreayne B (GKB), exerted strong hepatoprotection in the acetaminophen-induced cytotoxicity model. CYP 3A4 enzyme activity was strongly inhibited by the extract, hexane fraction, and GKB. The hexane fraction and GKB ameliorated acetaminophen-induced reductions in GSH levels and protected against cell death.