• 대한임베디드공학회논문지
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• 제18권3호
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• pp.89-100
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• 2023

Recently, on-device artificial intelligence (AI) solutions using mobile devices and embedded edge devices have emerged in various fields, such as computer vision, to address network traffic burdens, low-energy operations, and security problems. Although vision transformer deep learning models have outperformed conventional convolutional neural network (CNN) models in computer vision, they require more computations and parameters than CNN models. Thus, they are not directly applicable to embedded edge devices with limited hardware resources. Many researchers have proposed various model compression methods or lightweight architectures for vision transformers; however, there are only a few studies evaluating the effects of model compression techniques of vision transformers on performance. Regarding this problem, this paper presents a performance evaluation of vision transformers on embedded platforms. We investigated the behaviors of three vision transformers: DeiT, LeViT, and MobileViT. Each model performance was evaluated by accuracy and inference time on edge devices using the ImageNet dataset. We assessed the effects of the quantization method applied to the models on latency enhancement and accuracy degradation by profiling the proportion of response time occupied by major operations. In addition, we evaluated the performance of each model on GPU and EdgeTPU-based edge devices. In our experimental results, LeViT showed the best performance in CPU-based edge devices, and DeiT-small showed the highest performance improvement in GPU-based edge devices. In addition, only MobileViT models showed performance improvement on EdgeTPU. Summarizing the analysis results through profiling, the degree of performance improvement of each vision transformer model was highly dependent on the proportion of parts that could be optimized in the target edge device. In summary, to apply vision transformers to on-device AI solutions, either proper operation composition and optimizations specific to target edge devices must be considered.

• 생명과학회지
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• 제21권1호
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• pp.81-88
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• 2011

누에 분말을 이용하여 B. subtilis 및 A. kawachii 균주에 의한 고체 발효를 통해 얻어진 발효 누에분말의 발효시간에 따른 이화학적 특성(단백질 함량 및 단백질 분해 패턴) 및 생리활성 효과(항산화 작용, 환원력 및 혈전용해 활성)를 평가하였다. 누에 단백질 함량과 항산화 활성은 B. subtilis 및 A. kawachii 두 균주 발효 모두 12일째에 가장 높았으며, 발효시간 증가와 함께 증가하는 경향을 보였다. 발효 누에분말의 환원력은 B. subtilis 균주 발효에 의해서는 6일째에 A. kawachii 균주 발효에 의해서는 12일째 가장 높은 것으로 나타나 균주간에 차이가 있었다. 혈전 분해 활성은 B. subtilis 및 A. kawachii 두 균주 발효 모두 6일째에 가장 높았으며, 이러한 효과는 B. subtilis 발효 누에분말보다는 A. kawachii 발효 누에분말에서 더 높았다. SDS-PAGE상의 단백질 패턴 분석에서는 66-97 kDa 크기의 단백질 밴드가 B. subtilis 발효에 의해서는 발효 초기인 3일째 대부분 분해가 일어났으나, A. kawachii 발효 누에분말에서는 발효 3일째부터 차츰 분해되기 시작하여 12일째 분해가 대부분 이루어졌다. 따라서 미생물을 이용한 발효 누에에서 특정의 생리활성 작용을 기대하기 위해서는 사용하는 균종에 따라 발효 기간이 달라져야 한다는 것을 시사하였다.

• 생명과학회지
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• 제26권9호
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• pp.1015-1021
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• 2016

Pyrimidine 유도체의 일종인 5-fluorouracil (5-FU)은 광범위하게 사용되는 항암제의 일종으로, thymidylate synthase의 활성을 억제시켜 핵산의 합성 및 대사기능 자애 유발 물질이다. 본 연구에서는 Ewing′s 육종 CHP-100 세포에서 5-FU의 증식억제와 연관된 기전 해석으로 시도하였다. 본 연구의 결과에 의하면, 5-FU 처리 시간의 경과에 따른 CHP-100 세포의 증식억제가 세포주기 G1 arrest 유발에 따른 것임을 알 수 있었다. 5-FU에 의한 CHP-100 세포의 G1 arrest는 retinoblastoma protein (pRB)의 탈인산화에 따른 전사인자 E2F-1 및 E2F-4와의 결합 촉진과 연관성이 있었다. 비록 5-FU 처리가 cyclin-dependent kinases의 발현에는 크게 영향을 주지 않았으나, 정상배지에서 배양된 대조군에 비하여 cyclin A 및 B의 발현이 5-FU 처리 시간 의존적으로 억제되었다. 또한 5-FU에 의한 CHP-100 세포의 G1 arrest는 apoptosis 유도와 연관이 있음을 핵 내 염색질의 응축에 따른 apoptotic body의 형성증가, poly (ADP-ribose) polymerase의 단편화 및 annexin V 염색 등을 통하여 확인하였다. 아울러 5-FU는 pro-apoptotic Bax 단백질의 발현 증가 및 anti-apoptotic Bcl-2의 발현 감소를 통한 mitochondrial membrane potential의 소실을 촉진시켰으며, 이로 인하여 미토콘드리아에서 세포질로의 cytochrome c 유리가 증가시켰음을 알 수 있었다. 따라서 본 연구의 결과는 5-FU에 의한 CHP-100 세포의 증식억제와 연관된 G1 arrest 및 apoptosis 유도에는 pRB의 인산화 억제 및 미토콘드리아 기능의 손상이 최소한 관여하고 있음을 의미하는 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.24-34
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• 2020

Objective: The effects of Pleurotus ostreatus on the feed utilization of broad bean stalks (BBS), rape straw (RS), paddy straw (PS), and corn stalk (CS) was examined. Methods: The four roughages were co-cultured with Pleurotus ostreatus. The chemical composition; enzyme activities of laccase, carboxymethylcellulase (CMCase) and xylanase; carbohydrate and protein fractions (based on The Cornell Net Carbohydrate and Protein System [CNCPS]) were assessed at different days after inoculation (7, 14, 21, 28 d) and un-inoculated roughages (control, 0 d). The digestibility of nutrient components and the gas production of roughage with various incubation times were monitored at 0, 2, 4, 6, 9, 12, 24, 36, 48, 60, and 72 h using an in vitro ruminal fermentation method. Results: A higher CMCase activity (0.1039 U/mL) and earlier time to peak (14 d) were detected in Pleurotus ostreatus cultured with CS (p<0.05). Significantly, the incubation length-dependent responses of cumulative gas production were observed from 24 to 72 hours post fermentation (p<0.05), and these incubation length-dependent effects on cumulative gas production of PS and CS appeared earlier (24 h) for PS and CS than those (48 h) for BBS and RS (p<0.05). The fast-degradable carbohydrate (CA) content for all four roughages significantly increased over time (p<0.05). Nonetheless, increased degradation efficiency for CA treated with Pleurotus ostreatus was detected at both 21 and 28 days of incubation (p<0.05). With the exception of PS (p<0.05), there were no significant difference among the roughages (p>0.05) in slowly-degradable carbohydrate (CB2) at different incubation times (p<0.05). Conclusion: Assessment of the alterations in chemical composition, CNCPS system fractions, and the fermentation kinetics after biological pretreatment may yield a valuable database for evaluating the biological pretreatment of Pleurotus ostreatus in ruminant feed.

• 한국해안·해양공학회논문집
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• 제27권4호
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• pp.246-257
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• 2015

피해 자료의 부족에 따른 불확실성 뿐만 아니라 시간의 진행에 따른 불확실성을 고려하기 위하여 추계학적 확률과정을 이용하여 시간에 따른 구조물의 피해 경로를 정량적으로 추적하였다. 누적피해도와 내구년수의 분포함수를 시간의 함수로 산정하여 추계학적 확률과정을 적용할 때 주의해야 하는 중요한 특성들을 제시하였다. 특히, 본 연구에서는 추계학적 확률과정을 경사제 피복재에 적용하여 시간에 따른 누적 피해도를 추적할 수 있는 방법을 제안하였다. 확률과정의 매개변수들을 추정하기 위하여 개발된 표본경로기법을 이용하여 경사제 피복재의 시간에 따른 누적 피해도가 포화거동을 따른다는 사실이 확인되었다. 또한 누적 피해도 산정시 중요한 역할을 하는 멱함수의 지수를 정량적으로 산정하여 경사제 피복재의 누적 피해도를 시간에 따라 추적하는 것이 가능했다. 마지막으로 한계수준을 다양하게 변화시키면서 파괴확률의 거동특성을 해석하였다.

• 생명과학회지
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• 제19권2호
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• pp.249-255
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• 2009

Esculetin, a coumarin compound, has been known to inhibit proliferation and induce apoptosis in several types of human cancer cells. However, the molecular mechanisms involved in esculetin-induced apoptosis are still uncharacterized in human leukemia cells. In this study, we have investigated whether esculetin exerts anti-proliferative and apoptotic effects on human leukemia U937 cells. It was found that esculetin could inhibit cell viability in a time-dependent manner, which was associated with the induction of apoptotic cell death such as increased populations of apoptotic- sub G1 phase. Apoptosis of U937 cells by esculetin was associated with an inhibition of Bcl-2/Bax binding activity, formation of tBid, down-regulation of X-linked inhibitor of apoptotic protein (XIAP) expression, and up-regulation of death receptor 4 (DR4) and FasL expression. Esculetin treatment also induced the degradation of ${\beta}$-catenin and DNA fragmentation factor 45/inhibitor of caspase-activated DNase (DFF45/ICAD). Furthermore, a caspase-3 specific inhibitor, z-DEVD-fmk, significantly inhibited sub-G1 phase DNA content, morphological changes and degradation of ${\beta}$-catenin and DEE45/ICAD. These results indicated that a key regulator in esculetin-induced apoptosis was caspase-3 in human leukemia U937 cells.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.6165-6171
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• 2013

This study aimed to analyze the expression and clinical significance of cyclin G2 (CCNG2) in thyroid carcinoma and the biological effects of CCNG2 overexpression in a cell line. Immunohistochemistry and Western blotting were used to analyze CCNG2 protein expression in 63 cases of thyroid cancer and normal tissues to allow the relationship with clinical factors to be assessed. CCNG2 lentiviral and empty vectors were transfected into the thyroid cancer K1 cell line. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were applied to detect the mRNA and protein levels of CCNG2. MTT assay and cell cycle were also conducted to assess the influence of up-regulated expression of CCNG2 on K1 cell biology. The level of CCNG2 protein expression was found to be significantly lower in thyroid cancer tissue than normal tissues (P<0.05). Western blot: The relative amount of CCNG2 protein in thyroid cancer tissue was respectively found to be significantly lower than in normal tissues (P<0.05), correlating with lymph node metastasis, clinic stage and histological grade (P<0.05), but not gender, age or tumor size (P>0.05). Loss of CCNG2 expression correlated significantly with poor overall survival time on Kaplan-Meier analysis (P<0.05). The results for biological functions showed that K1 cell transfected CCNG2 had a lower survival fraction, a greater percentage in the G0/G1 phases, and lower cyclin-dependent kinase 2 (CDK2) protein expression compared with K1 cells non-transfected with CCNG2 (P<0.05). CCNG2 expression decreased in thyroid cancer and correlated significantly lymph node metastasis, clinic stage, histological grade and poor overall survival, suggesting that CCNG2 may play important roles as a negative regulator in thyroid cancer K1 cells by promoting degradation of CDK2.

• Journal of Veterinary Science
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• 제24권6호
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• pp.83.1-83.12
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• 2023

Background: Ellipticine (Ellip.) was recently reported to have beneficial effects on the differentiation of adipose-derived stem cells into mature chondrocyte-like cells. On the other hand, no practical results have been derived from the transplantation of bone marrow stem cells (BMSCs) in a rabbit osteoarthritis (OA) model. Objectives: This study examined whether autologous BMSCs incubated with ellipticine (Ellip.+BMSCs) could regenerate articular cartilage in rabbit OA, a model similar to degenerative arthritis in human beings. Methods: A portion of rabbit articular cartilage was surgically removed, and Ellip.+BMSCs were transplanted into the lesion area. After two and four weeks of treatment, the serum levels of proinflammatory cytokines, i.e., tumor necrosis factor α (TNF-α) and prostaglandin E2 (PGE2), were analyzed, while macroscopic and micro-computed tomography (CT) evaluations were conducted to determine the intensity of cartilage degeneration. Furthermore, immuno-blotting was performed to evaluate the mitogen-activated protein kinases, PI3K/Akt, and nuclear factor-κB (NF-κB) signaling in rabbit OA models. Histological staining was used to confirm the change in the pattern of collagen and proteoglycan in the articular cartilage matrix. Results: The transplantation of Ellip.+BMSCs elicited a chondroprotective effect by reducing the inflammatory factors (TNF-α, PGE2) in a time-dependent manner. Macroscopic observations, micro-CT, and histological staining revealed articular cartilage regeneration with the downregulation of matrix-metallo proteinases (MMPs), preventing articular cartilage degradation. Furthermore, histological observations confirmed a significant boost in the production of chondrocytes, collagen, and proteoglycan compared to the control group. Western blotting data revealed the downregulation of the p38, PI3K-Akt, and NF-κB inflammatory pathways to attenuate inflammation. Conclusions: The transplantation of Ellip.+BMSCs normalized the OA condition by boosting the recovery of degenerated articular cartilage and inhibiting the catabolic signaling pathway.

• BMB Reports
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• 제32권4호
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• pp.350-357
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• 1999

At concentrations of 1 mM, the protective effects of carnosine and related compounds including anserine, homocarnosine, histidine, ${\beta}$-alanine were investigated against copper-catalyzed oxidative damage to deoxyribose, ascorbic acid, human serum albumin, liposome, and erythrocytes. Carnosine and anserine reduced Cu (II) to bathocuproine-reactive Cu (I) in a time- a and a dose-dependent manner while the others did not. Carnosine reduced 86% of $100\;{\mu}M$ Cu (II) in 60 min. Carnosine, homocarnosine, anserine, and histidine inhibited copper-catalyzed deoxyribose degradation by 75, 66, 65, and 45%, respectively. In the presence of $1\;{\mu}M$ Cu (II), carnosine and related compounds inhibited ascorbic acid oxidation by 55-85% after incubation for 20 min. In the presence of 0.15 mM ascorbic acid and 0.8 mM $H_2O_2$, carnosine, anserine, homocarnosine, and histidine inhibited copper-catalyzed oxidation of human serum albumin by 41, 21, 29, and 24%, respectively, as determined by carbonyl formation. These compounds also significantly inhibited copper-catalyzed liposomal lipid peroxidation as measured by malondialehyde and lipid hydroperoxides. Carnosine, anserine, homocarnosine, and histidine inhibited hemolysis of bovine erythrocytes induced by 0.1 mM Cu (II). These results suggest that histidine-containing dipeptides may play an important role in protecting against free radical-mediated tissue damage.

• 한국미생물·생명공학회지
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• 제21권1호
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• pp.74-81
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• 1993

저온성 세균 Acinetobacter calcoaceticus A1-1의 유류분해 특성을 연구하기 위해 환경적 요인에 대한 영향을 살펴보았다. 이 세균의 성장율과 유화활성도에 대한 적정 환경조건은 온도 $15^{\circ}C$, pH 7.5, 염분도 0-3, 원유농도 0.1로 나타났고 질소원과 인원의 적정농도는$(NH_4)_2S0_4$과 $K_2HP0_4$, 형태로 각각 0.76 mM, 0.057mM이다. 온도에 따른 A.calcoaceticus A1-1의 유류분해 양상을 개스크로마토그라피로 분석한 결과 $10^{\circ}C$, $15^{\circ}C$에서 대부분의 탄화수소 피크가 감소되어 상당 정도의 유류분해를 관찰 할 수 있었다. 반면 $25^{\circ}C$의 경우에는 120시간 배양한 후에도 원유에 포함된 포화탄화수소 화합물들이 부분적으로만 분해되었다.