• Kyungpook Mathematical Journal
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• v.62 no.2
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• pp.289-321
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• 2022

The work realized by the authors of [4], [5] and [6] associates a non-negative matrix with positive integers entries to each dissection of a polygon. In the particular case of triangulations, these matrices called ℬ𝒞𝒥-matrices here contain valuable information of their frieze patterns, a concept introduced by Coxeter and Conway. This paper is concerned with the algebraic manipulation and properties of these matrices which are derived from operations acting on dissections.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.83-84
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.206-207
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.124-125
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• 2004

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2313-2316
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• 2015

Objective: To investigate the correlation between extracellular matrix protein-1 (ECM1) and the growth, metastasis and angiogenesis of laryngeal carcinoma. Materials and Methods: Forty-five samples with laryngeal benign and malignant tumors confirmed by pathology in Laiwu City People's Hospital from March 2006 to March 2011 were collected, in which there were 29 cases with laryngeal carcinoma and 16 with benign tumors. The expression of ECM1 and factor VIII-related antigens in patients with laryngeal carcinoma and those with benign tumors was respectively detected using immunohistochemical method, and the correlation between ECM1 staining grade and microvessel density (MVD) was analyzed. Results: In laryngeal carcinoma tissue, ECM1 was mainly expressed in cytoplasm, less in cytomembrane or intercellular substance. With abundant expression in the tissue of laryngeal benign tumors (benign mesenchymoma and hemangioma), ECM1 was primarily expressed in the connective tissue, which was different from the expression in laryngeal carcinoma tissue. The proportion of positive ECM1 staining (++) in patients with laryngeal carcinoma was dramatically higher than those with benign tumors (p<0.05), and that of strongly-positive ECM1 staining (+++) slightly higher. The results of Spearman nonparametric correlation analysis revealed that ECM1 staining grade in laryngeal carcinoma tissue had a significantly-positive correlation with MVD (r=0.866, p=0.000). Conclusions: ECM1 expression in laryngeal carcinoma is closely associated with tumor cell growth, metastasis and angiogenesis, which can be considered as an effective predictor in the occurrence and postoperative recurrence of laryngeal carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2175-2178
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• 2012

Purpose: Definite diagnosis of follicular thyroid carcinoma (FTC) is based on the presence of capsular or vascular invasion. To date, no reliable and practical method has been introduced to discriminate this malignant neoplasm from follicular thyroid adenoma (FTA) in fine needle aspiration biopsy material. Matrix metalloproteinase-2 (MMP-2), by degrading extracellular matrix, and caspase-3, by induction of apoptosis, have been shown to play important roles in carcinogenesis and aggressive behavior in many tumor types. The aim of this study was to examine expression of MMP-2 and caspase-3 in thyroid follicular neoplasms and to determine their usefulness for differential diagnosis. Method: Sixty FTAs and 41 FTCs were analysed immunohistochemically for MMP-2 and caspase-3. Result: MMP-2 was positive in 4 FTCs (9.8%), but in none of FTAs, with statistical significance (p= 0.025). Caspase-3 was positive in 30 (50%) of FTAs and in 27 (65.9%) of FTCs. Conclusion: Our results show MMP-2 expression only in FTCs and suggest that this protein may be a useful marker to confirm diagnosis of FTC versus FTA with 100% specificity and 100% predictive value of a positive test. We failed to show any differential diagnostic value for caspase-3 in thyroid follicular neoplasms.

• Biomolecules & Therapeutics
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• v.29 no.5
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• pp.483-491
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• 2021

Parkinson's disease (PD) is a neurodegenerative disorder that involves the loss of dopaminergic neurons in the substantia nigra (SN). Matrix metalloproteinases-8 (MMP-8), neutrophil collagenase, is a functional player in the progressive pathology of various inflammatory disorders. In this study, we administered an MMP-8 inhibitor (MMP-8i) in Leucine-rich repeat kinase 2 (LRRK2) G2019S transgenic mice, to determine the effects of MMP-8i on PD pathology. We observed a significant increase of ionized calcium-binding adapter molecule 1 (Iba1)-positive activated microglia in the striatum of LRRK2 G2019S mice compared to normal control mice, indicating enhanced neuro-inflammatory responses. The increased number of Iba1-positive activated microglia in LRRK2 G2019S PD mice was down-regulated by systemic administration of MMP-8i. Interestingly, this LRRK2 G2019S PD mice showed significantly reduced size of cell body area of tyrosine hydroxylase (TH) positive neurons in SN region and MMP-8i significantly recovered cellular atrophy shown in PD model indicating distinct neuro-protective effects of MMP-8i. Furthermore, MMP-8i administration markedly improved behavioral abnormalities of motor balancing coordination in rota-rod test in LRRK2 G2019S mice. These data suggest that MMP-8i attenuates the pathological symptoms of PD through anti-inflammatory processes.

• Advances in nano research
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• v.17 no.3
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• pp.197-211
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• 2024

This work investigates the thermo-mechanical vibration frequencies of an embedded composite nano-beam restrained with elastic springs at both ends. Composite nanobeam consists of a matrix and short fibers as reinforcement elements placed inside the matrix. An approach based on Fourier sine series and Stokes' transform is adopted to present a general solution that can examine the elastic boundary conditions of the short-fiber-reinforced nanobeam considered with the Halpin-Tsai model. In addition to the elastic medium effect considered by the Winkler model, the size effect is also considered on the basis of nonlocal strain gradient theory. After creating an eigenvalue problem that includes all the mentioned parameters, this problem is solved to examine the effects of fiber and matrix properties, size parameters, Winkler stiffness and temperature change. The numerical results obtained at the end of the study show that increasing the rigidity of the Winkler foundation, the ratio of fiber length to diameter and the ratio of fiber Young's modulus to matrix Young's modulus increase the frequencies. However, thermal loads acting in the positive direction and an increase in the ratio of fiber mass density to matrix mass density lead to a decrease in frequencies. In this study, it is clear from the eigenvalue solution calculating the frequencies of thermally loaded embbeded short-fiber-reinforced nanobeams that changing the stiffness of the deformable springs provides frequency control while keeping the other properties of the nanobeam constant.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5055-5060
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• 2013

Objective: Twist, a basic helix-loop-helix transcription factor, plays a key role in the metastatic progression of human cancer. Matrix metalloproteinase (MMP)-9 is an endopeptidase that digests basement membrane type IV collagen, therefore being possibly related to tumor progression. It has been reported that Twist and matrix metalloproteinase-9 (MMP-9) are expressed in gastric cancers. However, the exact roles of Twist and MMP-9 in tumor metastasis and prognosis remain unclear. The aim of this study was to casts light on this question. Methods:Twist and MMP-9 expression in tissue sections of 37 gastric carcinomas was evaluated with immunohistochemistry. The staining results were compared with clinicopatholgic features and to patients' outcome. Results: Twist positive expression was significantly increased in gastric cancer cases with lymph node metastasis (P=0.023). But no correlations were found between MMP-9 overexpression and clinicopathologic features, such as recurrence, TNM stage, and lymph node metastasis. Overall survival (OS) was significantly correlated with recurrence, serosa invasion, TNM stages, distant metastasis, and MMP-9 (P=0.027, 0.021, 0.000, 0.024 and 0.036, respectively). Disease-free survival (DFS) was prominently related to recurrence location, serosa invasion and TNM stages (P=0.000, 0.038 and 0.003, respectively). In the Cox regression multivariate analysis, TNM stage, distant metastasis and MMP-9 were significantly associated with prognosis of gastric cancer (P=0.002, 0.019, and 0.032, respectively). Conclusions: This study showed Twist positive expression to be significantly correlated with lymph node metastasis in gastric cancer. MMP-9 overexpression is associated with OS, suggesting that MMP-9 is a prognostic indicator for survival in patients with gastric cancer.

• Journal of Korea Water Resources Association
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• v.31 no.4
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• pp.439-448
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• 1998

There are many methods to calculate steady-state flowrate in a large water distribution system. Linear method which analyzes continuity equations and energy equations simultaneously is most widely used. Though it is theoretically simple, when it is applied to a practical water distribution system, it produces a very sparse coefficient matrix and most of its diagonal elements are to be zero. This sparsity characteristic of coefficient matrix makes it difficult to analyze pipe flow using the linear method. In this study, a graph theory is introduced to water distribution system analysis in order to prevent from producing ill-conditioned coefficient matrix and the technique is developed to produce positive-definite matrix. To test applicability of developed method, this method is applied to 22 pipes and 142 pipes system located nearby Taegu city. The results obtained from these applications show that the method can calculate flowrate effectively without failure in converage. Thus it is expected that the method can analyze steady state flowrate and pressure in pipe network systems efficiently. Keywords : pipe flow analysis, graph theory, linear method.