• Journal of applied mathematics & informatics
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• v.14 no.1_2
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• pp.225-235
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• 2004

The sign central matrices were characterized by Ando and Brualdi. And, the nearly sign central matrices were characterized by Lee and Cheon. In this paper, we give another characterization of nearly sign central matrices. Also, we introduce the nearly minimal sign central matrices and study the properties of nearly minimal sign central matrices.

• Journal of applied mathematics & informatics
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• v.10 no.1_2
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• pp.353-360
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• 2002

In this paper we study when a sign pattern matrix A and a sign pattern vector b have the property that the convex hull of the columns of each matrix with sign pattern A contains a vector with sign pattern b. This study generalizes the notion of sign central matrices.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.289-292
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• 2010

Purpose: Mycobacterium abscessus belongs to the group of rapid-growing atypical mycobacterium. The organism is ubiquitous and is found in soil, dust, and water. Although it rarely causes disease in humans, Mycobacterium abscessus has been associated with soft tissue infection. To the best of our knowledge, this is the first case report of facial soft tissue Mycobacterium abscessus infection in a healthy child in Korea. Methods: A 12-year-old girl presented with an erythematous skin lesion with serous discharge on her chin, which had been present for 3 weeks. On her history, she had a laceration wound on her chin at public bath and the lesion was repaired at emergency department immediately. Although conventional soft tissue infecton treatment, her lesion remains unhealed state and had serous discharge for 2 months. Moreover, we found a 1 cm sized nodular mass on her chin. Therefore we performed excision operation and referred the specimen to the laboratory for microbial and histopathologic study. Results: Pathology report confirmed the mass was enlarged lymph node with chronic necrotizing granulomatous inflammation with central microabscess. Non-Tuberculous mycobacterium identification test through tissue specimen resulted Mycobacterium abscessus. We prescribed clarithromycin for three weeks by oral administration as well as performed wound debridement and mass excision via previous wound. This way, her lesion appeared to be complete healing with minimal scarring. There were no evidence of inflammation sign or palpable mass. Conclusion: Although the prevalence is rare, Mycobacterium abscessus infections of soft tissue should be considered even in a healthy child with a lesion caused by trauma or which fails to respond to conventional treatment.