• Steel and Composite Structures
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• 제14권2호
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• pp.133-153
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• 2013

The concrete-filled steel tube (CFT) columns have several benefits of high load-bearing capacity, inherent ductility and toughness because of the confinement effect of the steel tube on concrete and the restraining effect of the concrete on local buckling of steel tube. However, the experimental research into the behavior of square CFT columns consisting of high-strength steel and high-strength concrete is limited. Six full scale CFT specimens were tested under flexural moment. The CFT columns consisted of high-strength steel tubes ($f_y$ = 325 MPa, 555 MPa, 900 MPa) and high-strength concrete ($f_{ck}$ = 80 MPa and 120 MPa). The ultimate capacity of high strength square CFT columns was compared with AISC-LRFD design code. Also, this study was focused on investigating the effect of high-strength materials on the structural behavior and the mathematical models of the steel tube and concrete. Nonlinear fiber element analyses were conducted based on the material model considering the cyclic bending behavior of high-strength CFT members. The results obtained from the numerical analyses were compared with the experimental results. It was found that the numerical analysis results agree well with the experimental results.

• Journal of Information Processing Systems
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• 제20권4호
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• pp.535-549
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• 2024

Facial expressions (FEs) serve as fundamental components for human emotion assessment and human-computer interaction. Traditional convolutional neural networks tend to overlook valuable information during the FE feature extraction, resulting in suboptimal recognition rates. To address this problem, we propose a deep learning framework that incorporates hierarchical feature fusion, contextual data, and an attention mechanism for precise FE recognition. In our approach, we leveraged an enhanced VGGNet16 as the backbone network and introduced an improved group convolutional channel attention (GCCA) module in each block to emphasize the crucial expression features. A partial decoder was added at the end of the backbone network to facilitate the fusion of multilevel features for a comprehensive feature map. A reverse attention mechanism guides the model to refine details layer-by-layer while introducing contextual information and extracting richer expression features. To enhance feature distinguishability, we employed islanding loss in combination with softmax loss, creating a joint loss function. Using two open datasets, our experimental results demonstrated the effectiveness of our framework. Our framework achieved an average accuracy rate of 74.08% on the FER2013 dataset and 98.66% on the CK+ dataset, outperforming advanced methods in both recognition accuracy and stability.

• The Journal of Korean Physical Therapy
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• 제17권4호
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• pp.589-600
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• 2005

The purposes of this study is to discuss and analyze the effect on the recovery from cut in sciatic nerve. This study used 9 weeks male rats of Sprague-Dawley family. Rat in groups 4 were treated with pulsed therapeutic ultrasound for 3 minutes. 3 times weekly at 3MHz respectively (intensity; $0.2W/cm^2,\;0.5W/Cm^2,\;10W/cm^2$); rat in group 1 received placebo ultrasound. In addition, changes of serum aspartate amino-transferase(AST) and creatine phosphokinase(CPK) levels were also demonstrated with diameter of individual muscle fasciculate and number of muscle fiber in each of three types of muscles located in gastrocnemius, soles. The results of comparing the changes in groups are as follows; 1. We found out that hypertrophic epineurium was present in sciatic nerve injured ultrasound treatment of groups. 2. In the gastrocnemius morphological investigation of the group I (control group), severe muscle atrophy were observed at the 7th days of the sciatic nerve injury. however, muscle atrophy of the group IV ($1.0W/cm^2$) were slightly recovered at the 14th days after treatment ultrasound. At the 28th days, muscular fibers were formed in polygon and were significantly recovered. 3. C-fos immunoreactive of the group II ($0.2W/cm^2$), III ($0.5W/cm^2$) were remarkably increased at the 1th day after treatment of ultrasound. Group IV were markedly deceased. 4. Brain-Derived Neurotrophic Factor(BDNF) immunoreactive of the group II, III were increased after 7 days of the sciatic nerve injury. Group IV were markedly increased from 14th days to 28th days after treatment of ultrasound. 5. A significant increase of serum AST levels were demonstrated in control group. However, serum AST levels of massage groups were significantly decreased compared to that of control group in followed order ; ($0.2W/cm^2<0.5W/cm^2<1.0W/cm^2$). 6. A significant increase of serum CK levels were demonstrated in control of group. However, serum CK levels of massage groups were significantly decreased compared to that of control group in followed order ; ($0.2W/cm^2<0.5W/cm^2<1.0W/cm^2$). The above results suggest that ultrasound treatment after peripheral nerve injury might reduce noxious stimuli, facilitate nerve recovery and effective in the functional improvement delaying muscle atrophy or degeneration.

• Korean Chemical Engineering Research
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• 제57권4호
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• pp.475-483
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• 2019

화학적 무기 중 혈액작용제는 전자전달계 내 효소의 철 이온과 반응하고 세포호흡을 정지시켜 사망을 초래한다. 혈액작용제는 활성탄의 미세공보다 분자크기가 작아 화학적 흡착이 유일한 제독방법이다. 본 연구는 SG 생활안전에서 개발한 SG-1 가스 여과기를 이용하여 혈액작용제 시아노겐 클로라이드(CK) 가스의 유입에 따른 유동해석을 수행하였다. 구리, 은, 아연 및 몰리브데늄 이온이 첨착된 ASZM TEDA 활성탄을 적용하여 가스 여과기 제작 시험 규정에 따라 화학적 흡착 모사를 수행하였으며 흡착 Kinetic을 적용하기 위해 선 수행된 흡착 베드에서 CK 가스 흡착 실험 결과를 분석하였다. 화학적 흡착을 통해 발생되는 가스 여과기 내부 압력강하 및 가스 흡착 질량 등 주요 변수의 동적거동을 예측하였다. CFD에서 다공성 물질을 적용할 때 사용하는 Ergun 방정식 대신 Granular와 Packed bed를 사용하여 활성탄 적용 가능 결과를 확인하였으며 시간에 따른 흡착 및 유속에 따른 흡착의 유동 해석에 대한 동적 모사를 수행하였다.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1295-1304
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• 2021

Modified Renshen Wumei decoction (MRWD), a famous traditional Chinese medicine, is widely used for treating persistent diarrhea. However, as the mechanism by which MRWD regulates diarrhea remains unknown, we examined the protective effects of MRWD on intestinal barrier integrity in a diarrhea model. In total, 48 male rats were randomly distributed to four treatment groups: the blank group (CK group), model group (MC group), Medilac-Vita group (MV group) and Chinese herb group (MRWD group). After a 21-day experiment, serum and colon samples were assessed. The diarrhea index, pathological examination findings and change in ᴅ-lactate and diamine oxidase (DAO) contents illustrated that the induction of diarrhea caused intestinal injury, which was ameliorated by MV and MRWD infusion. Metabolomics analysis identified several metabolites in the serum. Some critical metabolites, such as phosphoric acid, taurine, cortisone, leukotriene B4 and calcitriol, were found to be significantly elevated by MRWD infusion. Importantly, these differences correlated with mineral absorption and metabolism and peroxisome proliferator-activated receptor (PPAR) pathways. Moreover, it significantly increased the expression levels of TLR4, MyD88 and p-NF-κB p65 proteins and the contents of IL-1 and TNF-α, while the expression levels of occludin, claudin-1 and ZO-1 proteins decreased. These deleterious effects were significantly alleviated by MV and MRWD infusion. Our findings indicate that MRWD infusion helps alleviate diarrhea, possibly by maintaining electrolyte homeostasis, improving the intestinal barrier integrity, and inhibiting the TLR4/NF-κB axis.

• 대한교통학회지
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• 제24권1호
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• pp.19-28
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• 2006

항공수요의 급속한 팽창으로 항공기 운항의 증가와 공역 및 활주로의 혼잡도 심화로 인해 운영상 위험(Operational risk)이 급증하고 있어 체계적인 항공안전에 대한 위기관리시스템의 구축이 필요하다 항공안전 분야의 선진국일수록 평상시 비상대응체계 및 여러 가지 위험관리기법을 가동함으로써 조직의 긴장감 유지 및 예방안전의 도구로 활용하고 있다. 따라서 항공운송산업의 안전에 대해 총괄적인 관리 감독의 의무가 있는 항공안전본부 차원에서 이와 같은 과학적인 위기관리 모형을 이용한 위기관리체계의 도입이 필요하다. 위험요인분석 기법들은 데이터베이스가 구축되어 있거나, 충분한 정보와 자료가 있는 경우에는 사용될 수 있으나 현재의 국내 여건 상 충분한 자료의 확보가 곤란하여 실용적으로 사용되기가 어려운 것이 현실이다. 따라서 본 연구에서는 현재의 제한된 자료를 사용하여 실현가능 한 위험관리모형을 제시하기 위해 위험인자를 선정하고 각 위험인자에 대한 중요도와 발생빈도를 계산한 후 위험관리 모형을 제시하였다 이러한 위험관리 모형을 통해 항공운송분야에서 주기적 위험관리를 효과적으로 시행하기 위해서는 반드시 국가차원의 광범위한 자료의 수집이 선행되어야 한다.

• 한국발생생물학회지:발생과생식
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• 제14권3호
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• pp.155-162
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• 2010

The trophectoderm is one of the earliest cell types to differentiate in the forming placenta. It is an important for the initial implantation and placentation during pregnancy. Trophoblast stem cells (TBSCs) develop from the blastocyst and are maintained by signals emanating from the inner cell mass. However, several limitations including rarity and difficulty in isolation of trophoblast stem cells derived from blastocyst still exist. To establish a model for trophoblast differentiation, we isolated TBSCs from human term placenta ($\geq$38 weeks) and characterized. Cell cycle was analyzed by measuring DNA content by FACS analysis and phenotype of TBSCs was characterized by RT-PCR and FACS analysis. TBSCs have expressed various markers such as self-renewal markers (Nanog, Sox2), three germ layer markers (hNF68, alpha-cardiac actin, hAFP), trophoblast specific markers (CDX-2, CK7, HLA-G), and TERT gene. In FACS analysis, TBSCs isolated from term placenta showed that the majority of cells expressed CD13, CD44, CD90, CD95, CD105, HLA-ABC, cytokeratin 7, and HLA-G. Testing for CD31, CD34, CD45, CD71, vimentin and HLA-DR were negative. TBSCs were shown to decrease the growth rate when cultured in conditioned medium without FGF4/heparin as well as the morphology was changed to a characteristic giant cell with a large cytoplasm and nucleus. In invasion assay, TBSCs isolated from term placenta showed invasion activities in in vivo using nude mice and in vitro Matrigel system. Taken together, these results support that an isolation potential of TBSCs from term placenta as well as a good source for understanding of the infertility mechanism.

• Journal of Microbiology and Biotechnology
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• 제33권8호
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• pp.1013-1022
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• 2023

Arbuscular mycorrhizal fungi (AMF) are widespread soil endophytic fungi, forming mutualistic relationships with the vast majority of land plants. Biochar (BC) has been reported to improve soil fertility and promote plant growth. However, limited studies are available concerning the combined effects of AMF and BC on soil community structure and plant growth. In this work, a pot experiment was designed to investigate the effects of AMF and BC on the rhizosphere microbial community of Allium fistulosum L. Using Illumina high-throughput sequencing, we showed that inoculation of AMF and BC had a significant impact on soil microbial community composition, diversity, and versatility. Increases were observed in both plant growth (the plant height by 8.6%, shoot fresh weight by 12.1%) and root morphological traits (average diameter by 20.5%). The phylogenetic tree also showed differences in the fungal community composition in A. fistulosum. In addition, Linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that 16 biomarkers were detected in the control (CK) and AMF treatment, while only 3 were detected in the AMF + BC treatment. Molecular ecological network analysis showed that the AMF + BC treatment group had a more complex network of fungal communities, as evidenced by higher average connectivity. The functional composition spectrum showed significant differences in the functional distribution of soil microbial communities among different fungal genera. The structural equation model (SEM) confirmed that AMF could improve the microbial multifunctionality by regulating the rhizosphere fungal diversity and soil properties. Our findings provide new information on the effects of AMF and biochar on plants and soil microbial communities.

• 대한한의학방제학회지
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• 제31권3호
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• pp.157-169
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• 2023

Gracilaria Verrucosa (GV), a seaweed used in traditional Korean medicine, was studied for its effects on MI-induced heart failure in rats. MI is caused by a blocked coronary artery, leading to severe cardiac dysfunction. The study used a rat model to assess cardiac changes over time and evaluate the impact of GV on heart failure. Ischemia was induced through LAD ligation surgery, and the extent of ischemic area was measured as a prognostic factor. GV extract administration significantly improved cardiac morphology and reduced cardiac weight compared to the MI group. GV treatment also improved cardiac function, as evidenced by positive effects on chamber dilation during MI-induced heart failure. Parameters such as ejection fraction (EF) and fractional shortening (FS) were measured. The MI group showed decreased EF and FS compared to the sham group, while these parameters improved in the GV group. GV treatment also reduced levels of LDH, CPK, and CK-MB in the serum, indicating reduced myocardial damage. Histological analysis revealed that GV treatment attenuated cardiac hypertrophy and fibrosis, with reduced collagen deposition in the myocardium. Immunohistochemistry analysis showed suppressed expression of TGF-β1 and collagen 1, involved in fibrosis. In conclusion, GV showed potential in improving cardiac function in a rat model of MI-induced heart failure. It alleviated myocardial damage, attenuated cardiac hypertrophy and fibrosis, and suppressed fibrotic markers. Further studies are needed to explore its clinical efficacy and underlying mechanisms in cardiac diseases beyond animal models.

• 벤처창업연구
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• 제18권1호
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• pp.85-106
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• 2023

본 연구는 해외 농업스타트업(Agricultural startup)을 대상으로 그 성공요인을 검토 및 도출하고 이의 통합적 연구모델(Model)에 관해 연구하였다. 농업스타트업과 일반 스타트업은 창업 이후 자원기반관점에서 열악한 자원과 인프라가 존재한다는 공통점이 있지만, 농업 스타트업은 1차 산업 특성상 일반 스타트업과는 차별적 접근이 필요하다. 본 연구에서는 기업내부요인(인적자원/비전/유통망역량/자본역량/재배작물/물적자원/영농기술력 등)과 기업외부요인(농업인프라/법·규제/주변사회와의 관계 등)으로 접근하고 기존의 다양한 연구모델, 성공요인, 기업가정신을 중심으로 통합 가능한 연구모델을 구축하고자 하였다. 이를 통해 국내외 농업스타트업(agricultural Startup) 창업준비자, 창업가 등의 기업가들과 사업관련자, 그리고 통합적 이해를 필요로하는 연구자들에게 실질적 도움이 되는 통합모델(Model) 제시를 목적으로 하였다. 본 논문에서는 농업스타트업 성공요인 모델링(Modeling)을 위해 규모와 특성에 따라 3가지 형태(기존 농업스타트업, 중소규모기업 스타트업, 다국적기업 및 포괄적 접근)를 통해 표준모델을 수립하였다. 이를 통해 총 9개(영농관리, 외부환경, 경영자/창업자 특성, 기업정체성, 경영관리, 조직문화, 인프라, 사업화 역량, 지속가능성장)의 성공요인을 도출 하였다. 본 연구의 시사점은 다양한 국내외 농업스타트업 사례에 대해 '기업가정신'을 기반으로 농업스타트업 성공요인을 통합적으로 제시한점, 기존연구가 사례별 연구로 인해 나열식 성공요인 제시였다면 내용분석을 통한 의미적 범주화를 확인함으로써 향후 농업스타트업 성공요인에 대한 표준모델을 제시한 점, 그 결과 향후 관련연구의 체계적 연구와 실무적 실효성 확보를 위한 토대를 제시했다는데 있다.