• 기술혁신연구
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• 제3권1호
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• pp.213-236
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• 1995

Advanced Manufacturing Technology(AMT), a comprehensive collection of new technologies for the efficiency and flexibility of manufacturing systems has received a growing attention recently, AMT consists of various industrial and technological components, homogeneous in some aspects while heterogeneous in others. Thus, it is difficult but necessary task to construct a classification framework in which the relationship among individual technologies are depicted in a meaningful fashion. In this, paper, we propose a hierarchical framework in which the objective and criteria of classification are decomposed into three level: industrialization, development and application of AMT. At the first and highest level, the main interest is to "industrialize" AMT. The major actors at this level are policy makers(public sector) and top management(private sector) and the primary classification criterion is the interrelationship between industry and technology. At the middle level exist system engineers whose main objective is to "develop" new technologies and/or systematize individual technologies. At the final and bottom level, shop floor managers need to "apply" AMT in order to enhance the efficiency and flexibility of manufacturing process. It should be stressed that, as a whole, the above three levels should be interactively linked to that each level contributes to the balanced development of AMT.

• BMB Reports
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• 제57권6호
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• pp.263-272
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• 2024

Amyloid-β (Aβ) is one of the amyloidogenic intrinsically disordered proteins (IDPs) that self-assemble to protein aggregates, incurring cell malfunction and cytotoxicity. While Aβ has been known to regulate multiple physiological functions, such as enhancing synaptic functions, aiding in the recovery of the blood-brain barrier/brain injury, and exhibiting tumor suppression/antimicrobial activities, the hydrophobicity of the primary structure promotes pathological aggregations that are closely associated with the onset of Alzheimer's disease (AD). Aβ proteins consist of multiple isoforms with 37-43 amino acid residues that are produced by the cleavage of amyloid-β precursor protein (APP). The hydrolytic products of APP are secreted to the extracellular regions of neuronal cells. Aβ 1-42 (Aβ42) and Aβ 1-40 (Aβ40) are dominant isoforms whose significance in AD pathogenesis has been highlighted in numerous studies to understand the molecular mechanism and develop AD diagnosis and therapeutic strategies. In this review, we focus on the differences between Aβ42 and Aβ40 in the molecular mechanism of amyloid aggregations mediated by the two additional residues (Ile41 and Ala42) of Aβ42. The current comprehension of Aβ42 and Aβ40 in AD progression is outlined, together with the structural features of Aβ42/Aβ40 amyloid fibrils, and the aggregation mechanisms of Aβ42/Aβ40. Furthermore, the impact of the heterogeneous distribution of Aβ isoforms during amyloid aggregations is discussed in the system mimicking the coexistence of Aβ42 and Aβ40 in human cerebrospinal fluid (CSF) and plasma.

• 한국농공학회논문집
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• 제57권3호
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• pp.109-120
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• 2015

Spatial heterogeneous characteristics of solar radiation energy from Climate Change gives rise to energy imbalance in the general ecological system including water resources. This study is to estimate the $CO_2$ flux of South Korea using Terra MODIS image and to assess the reliability of MODIS data from the ground measured $CO_2$ flux by eddy covariance flux tower data at 3 locations (two at mixed forest area and one at rice paddy area). The MODIS Gross Primary Productivity (GPP) product (MOD17A2), 8-day composite at 1-km spatial resolution was adopted for the spatial $CO_2$ flux generation. The MOD17A2 data by noise like cloud and snow in a day were tried to fill by Inverse Distance Weighted (IDW) method from valid pixels and the damping effect of MOD17A2 data were corrected by Quality Control (QC) flag. The MODIS $CO_2$ flux was estimated as the sum of GPP and Re (ecosystem respiration) by Lloyd and Taylor method (1994). The determination coefficient ($R^2$) between MODIS $CO_2$ and flux tower $CO_2$ for 3 years (2011~2013) showed 0.55 and 0.60 in 2 mixed forests and 0.56 in rice paddy respectively. The $CO_2$ flux generally fluctuated showing minus values during summer rainy season (from July to August) and maintaining plus values for other periods. The MODIS $CO_2$ flux can be a useful information for extensive area, for example, as a reliable indicator on ecological circulation system.

• Nuclear Engineering and Technology
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• 제15권4호
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• pp.267-279
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• 1983

우라늄 및 플루토늄을 핵연료로 이용하고 경수를 감속재로 쓰는 원자로에 대한 해석적 체제를 수립하였다. 이 체제는 두개의 주요 전산코드로 구성되어 있는 바, 하나는 단위격자 세포코드인 KICC로서 이는 GAM및 THERMOS의 이론적인 기초에 여러가지 현상을 적절하게 포현할 수 있는 근사식을 결합한 것이다. 다른 하나는 다차원 확산-연소 방정식코드인 KIDD이다. 이 체제는 다양한 종류의 임계실험로에 대하여 철저한 검증계산을 수행하므로써 그 신뢰성을 입증하였다. 즉 서로 다른 노심구조를 가진 19가지의 비균질 임계실실험로에 대하여 유효증배계수를 계산한 결과 이의 평균치 1.0006, 표준편차 0.0039로서 잘 일치하였다. 또한 우라늄과 플루토늄을 핵 연료로 사용하는 여러종류의 임계로에 대하여 출력분포를 계산하여 측정치와 비교하였으며 계산치는 최대 오차 $\pm$5%이내에서 측정치에 일치하였다. 이러한 사실은 KICC/KIDD체제가 경수로의 해석에 아주 유용한 도구가 됨을 밝혀 준다.

• Korean Journal of Radiology
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• 제24권3호
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• pp.190-203
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• 2023

Objective: We aimed to assess and validate the radiologic and clinical factors that were associated with recurrence and survival after curative surgery for heterogeneous targetoid primary liver malignancies in patients with chronic liver disease and to develop scoring systems for risk stratification. Materials and Methods: This multicenter retrospective study included 197 consecutive patients with chronic liver disease who had a single targetoid primary liver malignancy (142 hepatocellular carcinomas, 37 cholangiocarcinomas, 17 combined hepatocellular carcinoma-cholangiocarcinomas, and one neuroendocrine carcinoma) identified on preoperative gadoxetic acid-enhanced MRI and subsequently surgically removed between 2010 and 2017. Of these, 120 patients constituted the development cohort, and 77 patients from separate institution served as an external validation cohort. Factors associated with recurrence-free survival (RFS) and overall survival (OS) were identified using a Cox proportional hazards analysis, and risk scores were developed. The discriminatory power of the risk scores in the external validation cohort was evaluated using the Harrell C-index. The Kaplan-Meier curves were used to estimate RFS and OS for the different risk-score groups. Results: In RFS model 1, which eliminated features exclusively accessible on the hepatobiliary phase (HBP), tumor size of 2-5 cm or > 5 cm, and thin-rim arterial phase hyperenhancement (APHE) were included. In RFS model 2, tumors with a size of > 5 cm, tumor in vein (TIV), and HBP hypointense nodules without APHE were included. The OS model included a tumor size of > 5 cm, thin-rim APHE, TIV, and tumor vascular involvement other than TIV. The risk scores of the models showed good discriminatory performance in the external validation set (C-index, 0.62-0.76). The scoring system categorized the patients into three risk groups: favorable, intermediate, and poor, each with a distinct survival outcome (all log-rank p < 0.05). Conclusion: Risk scores based on rim arterial enhancement pattern, tumor size, HBP findings, and radiologic vascular invasion status may help predict postoperative RFS and OS in patients with targetoid primary liver malignancies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권1호
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• pp.195-215
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• 2021

Multipath Transport Control Protocol (MPTCP) is a transport layer protocol that enables multiple TCP connections across various paths. Due to path heterogeneity, it incurs more energy in a multipath wireless network. Recent work presents a set of approaches described in the literature to support systems for energy consumption in terms of their performance, objectives and address issues based on their design goals. The existing solutions mainly focused on the primary system model but did not discourse the overall system performance. Therefore, this paper capitalized a novel stochastically multipath scheduling scheme for data and path capacity variations. The scheduling problem formulated over MPTCP as a stochastic optimization, whose objective is to maximize the average throughput, avoid network congestion, and makes the system more stable with greater energy efficiency. To design an online algorithm that solves the formulated problem over the time slots by considering its mindrift-plus penalty form. The proposed solution was examined under extensive simulations to evaluate the anticipated stochastic optimized MPTCP (so-MPTCP) outcome and compared it with the base MPTCP and the energy-efficient MPTCP (eMPTCP) protocols. Simulation results justify the proposed algorithm's credibility by achieving remarkable improvements, higher throughput, reduced energy costs, and lower-end to end delay.

• 공업화학
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• 제25권2호
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• pp.215-221
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• 2014

염기 처리에 의한 간단한 방법으로 합성된 $MnO_2$ (B-$MnO_2$)는 불균일 촉매시스템으로 호기성 조건에서 효과적인 아민 산화반응을 보여주었다. 이 B-$MnO_2$ 촉매는 다양한 종류의 방향족, 이원자 화합물, 비활성 지방족 등의 아민의 전환에 높은 활성과 선택성을 보여주었다. 이러한 산화반응은 온화한 온도($50^{\circ}C$)와 대기압의 공기 조건하에서 아민을 중간체인 이민으로 전환하고 자가 축합(self-condensation) 또는 산화적 탈수소화(oxidative dehydrogenation)을 통해 다이이민(diimine) 또는 나이트릴(nitrile)을 생성하였다. 사용된 촉매는 여과로 쉽게 분리할 수 있었고 5번 이상의 재사용 실험에서도 일정이상의 높은 수율을 보여주었다. 따라서 B-$MnO_2$는 아민 산화반응을 통해 이민과 나이트릴을 얻음에 있어 경제적으로나 환경친환적으로 효과적인 면을 보여 줌으로써, 그린화학(green chemistry)의 목적에 적합하다.

• 한국의학물리학회지:의학물리
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• 제31권3호
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• pp.54-62
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• 2020

Dose calculation algorithms play an important role in radiation therapy and are even the basis for optimizing treatment plans, an important feature in the development of complex treatment technologies such as intensity-modulated radiation therapy. We reviewed the past and current status of dose calculation algorithms used in the treatment planning system for radiation therapy. The radiation-calculating dose calculation algorithm can be broadly classified into three main groups based on the mechanisms used: (1) factor-based, (2) model-based, and (3) principle-based. Factor-based algorithms are a type of empirical dose calculation that interpolates or extrapolates the dose in some basic measurements. Model-based algorithms, represented by the pencil beam convolution, analytical anisotropic, and collapse cone convolution algorithms, use a simplified physical process by using a convolution equation that convolutes the primary photon energy fluence with a kernel. Model-based algorithms allowing side scattering when beams are transmitted to the heterogeneous media provide more precise dose calculation results than correction-based algorithms. Principle-based algorithms, represented by Monte Carlo dose calculations, simulate all real physical processes involving beam particles during transportation; therefore, dose calculations are accurate but time consuming. For approximately 70 years, through the development of dose calculation algorithms and computing technology, the accuracy of dose calculation seems close to our clinical needs. Next-generation dose calculation algorithms are expected to include biologically equivalent doses or biologically effective doses, and doctors expect to be able to use them to improve the quality of treatment in the near future.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3239-3245
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• 2012

Gliomas are a group of heterogeneous primary central nervous system tumors. Hyperthermia has proven to be a potential therapeutic tool for cancers in the clinic. However, the molecular mechanisms of hyperthermia remain unclear. The objective of this study was to investigate the effects of hyperthermia on the invasiveness in C6 glioma cells and related molecular pathways. Here our data show hyperthermia stimulated the release of tumor necrosis factor-alpha (TNF-${\alpha}$) and decreased C6 glioma cell migration and invasive capability at 30, 60, 120 and 180 min; with increased spontaneous apoptosis in C6 glioma cells at 120 min. We also found mitogen-activated protein kinase (P38 MAPK) protein expression to be increased and nuclear factor-kappa B (NF-${\kappa}B$) protein expression decreased. Based on the results, we conclude that hyperthermia alone reduced invasion of C6 glioma cells through stimulating TNF-${\alpha}$ signaling to activate apoptosis, enhancing P38 MAPK expression and inhibiting the NF-${\kappa}B$ pathway, a first report in C6 rat glioma cells.

• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8753-8757
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• 2014

Background: Glioma is a heterogeneous central nervous system (CNS) tumor group that encompasses different histological subtypes with high variability in prognosis. The lesions account for almost 80% of primary malignant brain tumors. The aim of this study is to extend our understanding of the glioma epidemiology in the central Tunisian region. Materials and Methods: We analyzed 393 gliomas recorded in cancer registry of central Tunisia from 1993 to 2012. Crude incidence rates (CR) and world age-standardized rates (ASR) were estimated using annual population data size and age structure. Statistic correlations were established using Chi-square and Kaplan-Meier test. Results: Tunisian glioma patients were identified with a mean age at diagnosis of 48 years and 1.5 sex ratio (male/female). During the 19 years period of study the highest incidence value was observed in male group between 1998 and 2002 (CR: 0.28, ASR: 0.3). Incidence results underline increasing high grade glioma occurring in the adulthood in the last period (2007-2012). Median survival was 27 months, with 1-, 2- and 5-year survival rates of 42%, 30% and 26%, respectively. Survival was greater in patients with younger age, lower tumor grade, infratentrial tumor location and undergoing a palliative treatment. Conclusions: This central Tunisia gliomas registry study provides important information that could improve glioma management and healthcare practice.