• Clinical Endoscopy
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• 제56권1호
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• pp.55-64
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• 2023

Background/Aims: Endoscopic submucosal dissection (ESD) has been established as a treatment modality for superficial esophageal squamous cell carcinoma (ESCC). Long-term follow-up data are lacking in Western countries. The aim of this study was to analyze long-term survival in a Western center. Methods: Patients undergoing ESD for ESCC were included. The analysis was performed retrospectively using a prospectively collected database. Results: R0 resection rate was 96.7% (59/61 lesions in 58 patients). Twenty-seven patients (46.6%) fulfilled the curative resection criteria (M1/M2) (group A), 11 patients (19.0%) had M3 lesions without lymphovascular invasion (LVI) (group B), and 20 patients (34.5%) had lesions with submucosal invasion or LVI (group C). Additional treatment was recommended after non-curative resection. It was not performed in 20/31 patients (64.5%), mainly because of comorbidities (75%). Twenty-nine out of 58 (50.0%) patients died during a mean follow-up of 3.7 years. Death was related to ESCC in 17.2% (5/29) of patients. The disease-specific survival rate after curative resection was 100%. Overall survival rates after 5 years were 61.5%, 63.6% and 28.1% for groups A, B, and C, respectively. The overall survival was significantly worse after non-curative resection (p=0.038). Conclusions: Non-curative resection is frequent after ESD for ESCC in Western patients. The long-term prognosis is limited and mainly determined by comorbidity. Early diagnosis and pre-interventional assessments need to be improved.

• The Korean Journal of Physiology and Pharmacology
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• 제17권1호
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• pp.51-56
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• 2013

Many intracellular proteins and signaling cascades contribute to the sensitivity of N-methyl-D-aspartate receptors (NMDARs). One such putative contributor is the serine/threonine kinase, protein kinase C (PKC). Activation of PKC by phorbol 12-myristate 13-acetate (PMA) causes activation of extracellular signal-regulated kinase (ERK) and promotes the formation of new spines in cultured hippocampal neurons. The purpose of this study was to examine which PKC isoforms are responsible for the PMA-induced augmentation of long-term potentiation (LTP) in the CA1 stratum radiatum of the hippocampus in vitro and verify that this facilitation requires NMDAR activation. We found that PMA enhanced the induction of LTP by a single episode of theta-burst stimulation in a concentration-dependent manner without affecting to magnitude of baseline field excitatory postsynaptic potentials. Facilitation of LTP by PMA (200 nM) was blocked by the nonspecific PKC inhibitor, Ro 31-8220 ($10{\mu}M$); the selective $PKC{\delta}$ inhibitor, rottlerin ($1{\mu}M$); and the $PKC{\varepsilon}$ inhibitor, TAT-${\varepsilon}V1$-2 peptide (500 nM). Moreover, the NMDAR blocker DL-APV ($50{\mu}M$) prevented enhancement of LTP by PMA. Our results suggest that PMA contributes to synaptic plasticity in the nervous system via activation of $PKC{\delta}$ and/or $PKC{\varepsilon}$, and confirm that NMDAR activity is required for this effect.

• Preventive Nutrition and Food Science
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• 제15권3호
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• pp.189-195
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• 2010

Water extracts from 20 medicinal plants, traditionally used for postmenopausal symptoms in Korea, were examined for their vasorelaxant activity in isolated rat thoracic aorta rings precontracted with norepinephrine (NE). Among the 20 medicinal plants, Cornus officinalis (CoEx, 0.3 mg/mL), Schisandra chinensis (ScEx, 0.3 mg/mL), Erythrina variegate (EvEx, 0.3 mg/mL), and Epimedium koreanum (EkEx, 0.3 mg/mL) showed rapid relaxation of endothelium-intact aorta ($69\pm4%$, $40\pm3%$, $25\pm2%$, and $23\pm3%$ of active tone induced by NE, respectively). In contrast, the extracts of Erythrina variegata (EvEx), Angelica gigas (AgEx), Pueraria thunbergiana (PtEx), and EkEx lead to gradual (i.e., long-term) relaxation to baseline in endothelium-intact vessels. The time to complete relaxation was 20～40 min. These 6 plant extracts were selected for the investigation of possible underlying mechanisms. The CoEx-, ScEx-, or EkEx-induced rapid relaxations were virtually abolished by endothelium denudation, and were significantly inhibited by pretreatment with nitric oxide (NO) synthase inhibitor $N^G$-nitro-L-arginine (L-NNA, 10 ${\mu}M$), indicating that increased formation of NO might contribute to the endothelium-mediated relaxation. In long-term responses, the endothelium denudation did not affect PtEx-induced relaxation, whereas it delayed responses by EvEx and AgEx, and significantly inhibited the effect of EkEx. Among EvEx, AgEx, and PtEx, EvEx attenuated the $CaCl_2$-induced vasoconstriction in high-potassium depolarized medium, implying that EvEx is involved in inhibition of the extracellular calcium influx to smooth muscle through voltage dependent calcium channels. These results provide the scientific rationale for the interrelationships between the use of 20 medicinal plants and their effects on cardiovascular health in estrogen deficient conditions.

• 대한약리학회지
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• 제29권2호
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• pp.237-244
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• 1993

소 부신수실 크롬친화성 세포(BAMC)에서 $[Met^5]-enkephalin$ (ME)의 분비와 Proenkephalin A (proENK) mRNA의 함량에 대한 nicotine의 영향과 이에 대한 indomethacin, nordihydroguaiaretic acid(NDGA) 및 captopril의 작용을 연구하였다. 10 uM Nicotine으로 BAMC 세포를 장기간 자극시 proENK mRNA의 함량과 배양액으로의 ME 분비가 유의하게 증가하였다. BAMC 세포를 NDGA(lipoxygenase 억제제, 10 uM), indomethacin (cyclooxygenase 억제제), captopril (angiotensin 변환효소 억제제)만으로 처리시에는 ME 분비와 proENK mRNA의 함량에 영향이 없었다. Nicotine에 의한 ME 분비와 proENK mRNA 함량의 증가는 NDGA에 의하여 억제되었다. 그러나 indomethacin과 captopril은 nicotine의 작용에 대하여 아무 영향이 없었다. 이들 결과는 nicotine에 의한 ME 분비와 proENK mRNA 함량의 증가가 부분적으로 lipoxygenase 경로에 의해 매개되며, cyclooxygenase 및 내재성 renin-angiotensin 경로는 관련되지 않음을 나타낸다.

• Structural Engineering and Mechanics
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• 제20권2호
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• pp.173-189
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• 2005

The paper presents a finite element model for studying timber-concrete composite beams under long-term loading. Both deformability of connection system and rheological behaviour of concrete, timber and connection are fully considered. The creep of component materials and the influence of moisture content on the creep of timber and connection, the so-called "mechano-sorptive" effect, are evaluated by means of accurate linear models. The solution is obtained by applying an effective step-by-step procedure in time, which does not require storing the whole stress history in some points in order to account for the creep behaviour. Hence the proposed method is suitable for analyses of composite beams subjected to complex loading and thermo-hygrometric histories. The possibility to accurately predict the long-term response is then shown by comparing numerical and experimental results for different tests.

• 한국연초학회지
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• 제14권1호
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• pp.57-65
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• 1992

The quality of cut tobacco will be deteriorated due to weather conditions such as temperature and relative humidity, when shipping and long term storaging. The change of equilibrium moisture contents in cut tobacco were under influence of relative humidity and temperature but not humectants. Therefore internal packing materials are necessary for cut tobacco to maintain initial quality, including taste, flavour and musty smell during shipping or storaging. When packing cut tobacco for shipping or long term storaging, desiralbe packing density was 200/$m^2$, For the long term storage under R.H 90% and 3$0^{\circ}C$, polyethylene film thickness suitable for packing material are above 100$\mu$, which resulted in 42days of shelf life.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.380-385
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• 2001

본 논문에서는 기존의 역전파 알고리즘(Back-propagation Algorithm)의 문제점인 지역 최소점(Local Minimum point) 빠질 위험을 제거함과 동시에 학습속도(learning-speed)를 빠르게 하기 위해서 모먼팀을 갖는 PID 역전파 알고리듬(PIDBPMT: PID Back-Propagation algorithm with Momentum Term)을 제안하여 모먼텀 항을 갖는 신경망 PID 제어기를 설계하였다. 그 제어기를 D.C 서보 모터를 구동원으로 하는 위치제어계에서 적용하여 시뮬레이션으로 그 성능을 검정하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 추계학술발표대회
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• pp.414-416
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• 2022

개체단위 감정분석(Aspect-Based Sentiment Analysis)는 자연어 처리에서 중요한 연구분야이다. 이는 입력 문장중에 존재하는 aspect term 의 감정 극성을 분석하는 것이 목적이다. 이 분야에서 현재 많이 사용되는 모델은 대부분 로컬 텍스트 또는 로컬 덱스트와 aspect term 사이의 관계에 주목하고 있다. 로켈 텍스트에 비해 글로벌 텍스트는 로컬 텍스트 뒤에 aspect term 내용을 추가해서 문장중에 있는 aspect term 내용을 더 깊게 학습할 수 있다고 생각한다. 본 논문에서는 새로운 masked attention 메커니즘을 사용하고 attention 메커니즘의 입력으로 글로벌 텍스트중에 있는 로컬 텍스트를 가로채어 전체 글로벌 텍스트의 내용과 융합한다. 이 방법은 semeval2014 데이터 셋에서 매우 좋은 결과를 얻었다.

• 한국해안·해양공학회논문집
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• 제25권4호
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• pp.255-265
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• 2013

우리나라 연안해역에서 기왕에 발표된 조위와 조류 조화상수를 수집하여 정리하고, 국립해양조사원에서 관측한 서해안 검조소의 장기 조위자료와 경기만과 남서해안의 단기 조위자료를 조화분석하였다. 이 자료를 토대로 우리나라 연안해역에서 조석과 조류의 분포특성 특히 비선형성을 조사하였으며, 장기 조위자료를 조화분석한 결과를 토대로 $M_2$ 분조와 $M_4$ 분조의 시간변화와 개발사업과의 관련성에 대해서 연구하였다. $M_2$ 분조의 진폭은 서해안 전역에서 과거에 비해서 전반적으로 감소하고 있었으며, 위상은 빨라지고 있었다. $M_2$ 분조의 비선형 상호작용에 의해 발생되는 비선형 분조인 $M_4$ 분조도 $M_2$ 분조와 마찬가지로 전반적으로 진폭은 감소하고, 위상은 빨라지고 있었다. 조석의 비선형성은 서해남부해역에서 크게 나타났으며, 군산해역에서도 비교적 뚜렷하게 나타났다. 조류 비선형성은 조석과 마찬가지로 지역적으로는 서해남부해역에서 크게 나타났으며, 전반적으로 유속이 빠른 서해와 남해의 대부분 조석수로에서도 비교적 크게 나타났다. 서해에서 전반적으로 조석 비선형성이 해안개발사업의 효과로 증가하고 있었으며, 서해 중부와 북부의 창조우세특성과 남부의 낙조우세특성은 각각 심화되고 있었다. 특히 새만금방조제 건설은 서해중부와 남부의 조석체계를 다른 사업들에 비해서 크게 변화시켰다.

• 한국도로학회논문집
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• 제18권1호
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• pp.63-72
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• 2016

PURPOSES : The use of roller-compacted concrete pavement (RCCP) is an environmentally friendly method of construction that utilizes the aggregate interlock effect by means of a hydration reaction and roller compacting, demonstrating a superb structural performance with a relatively small unit water content and unit cement content. However, even if an excellent structural performance was secured through a previous study, the verification research on the environmental load and long-term durability was conducted under unsatisfactory conditions. In order to secure longterm durability, the construction of an appropriate internal air-void structure is required. In this study, a method of improving the long-term durability of RCCP will be suggested by analyzing the internal air-void structure and relevant durability of roller-compacted concrete. METHODS : The method of improving the long-term durability involves measurements of the air content, air voids, and air-spacing factor in RCCP that experiences a change in terms of the kind of air-entraining agent and chemical admixture proportions. This test should be conducted on the basis of test criteria such as ASTM C 457, 672, and KS F 2456. RESULTS : Freezing, thawing, and scaling resistance tests of roller compacted concrete without a chemical admixture showed that it was weak. However, as a result of conducting air entraining (AE) with an AE agent, a large amount of air was distributed with a range of 2~3%, and an air void spacing factor ranging from 200 to $300{\mu}m$ (close to $250{\mu}m$) coming from PCA was secured. Accordingly, the freezing and thawing resistance was improved, with a relative dynamic elastic modulus of more than 80%, and the scaling resistance was improved under the appropriate AE agent content rate. CONCLUSIONS : The long-term durability of RCCP has a direct relationship with the air-void spacing factor, and it can be secured only by ensuring the air void spacing factor through air entraining with the inclusion of an AE agent.