Publications by authors named "Yoon-Suk Oh"

The effect of a 5 mol% La2O3 addition on the forming behavior and compositional variation at interface between a 4 mol% Yttria (Y2O3) stabilized ZrO2 (4YSZ) top coat and bond coat (NiCrAlY) as a thermal barrier coating (TBC) has been investigated. Top coats were deposited by electron beam physical vapor deposition (EB PVD) onto a super alloy (Ni-Cr-Co-Al) substrate without pre-oxidation of the bond coat. Top coats are found to consist of dense columnar grains with a thin interdiffusion layer between metallic bond coats.

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It is of critical importance to improve toughness, strength, and wear-resistance together for the development of advanced structural materials. Herein, we report on the synthesis of unoxidized graphene/alumina composite materials having enhanced toughness, strength, and wear-resistance by a low-cost and environmentally benign pressure-less-sintering process. The wear resistance of the composites was increased by one order of magnitude even under high normal load condition (25 N) as a result of a tribological effect of graphene along with enhanced fracture toughness (KIC) and flexural strength (σf) of the composites by ~75% (5.

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We investigated the role of endogenous stromal cell-derived factor-1 (SDF-1; CXCL12) in the survival and proliferation of acute myeloid leukemia (AML) cells in vitro. CD34(+) cells from the peripheral blood of five patients with AML, as well as five AML cell lines, produced and secreted SDF-1. Knock-down of endogenous SDF-1 expression using siRNA technology downregulated the constitutive phosphorylation of SDF-1-related signaling molecules and significantly inhibited spontaneous proliferation of the AML cell lines during a 3-day incubation in serum-free conditions.

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Given the important role of CXCR4 in cancer metastasis, microenvironmental factors that modulate CXCR4 may have an impact on the process of tumor expansion. Hypoxia is a common feature of solid tumors and a significant microenvironmental factor that drives aggressive behavior. CXCR4 is upregulated in several cancer cells under hypoxic conditions, suggesting a relationship between tumor hypoxia and CXCR4.

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Lymph node metastasis is considered to be a significant prognostic factor for early gastric cancer (EGC). However, no real consensus exists on which patient and/or tumor characteristics are associated with lymph node metastasis. We investigated whether stromal cell-derived factor (SDF)-1α expression correlates with lymph node metastasis in patients with EGC by immunohistochemically examining the expression of SDF-1α in 138 archival tissue specimens of EGC.

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Purpose: Although recent studies have suggested that chemokine (C-X-C motif) ligand 12 (CXCL12) is important in the progression of various malignancies, its role in gallbladder carcinoma (GBC) remains unknown. We investigated CXCL12 expression in GBC and its biologic and prognostic role in GBC tumorigenesis.

Experimental Design: We examined CXCL12 expression in tumor specimens from 72 patients with GBC by immunohistochemistry and analyzed the correlation between CXCL12 expression and clinicopathologic factors or survival.

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Background: Antagonists of CXC chemokine receptor 4 (CXCR4), including AMD3100, induce peripheral mobilization of hematopoietic stem cells and have been approved for clinical use. We explored whether the CXCR4 antagonists affected the survival and proliferation of myeloid leukemia cells in vitro.

Methods: The effects of CXCR4 antagonists AMD3100 and T140 on the survival and proliferation of myeloid leukemia cell lines (U937, HL-60, MO7e, KG1a, and K562) as well as CD34(+) cells obtained from patients with AML and CML were analyzed by flow cytometry by using annexin V and a colorimetric cell proliferation assay.

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Chemokine stromal cell-derived factor (SDF)-1α and its receptor CXC chemokine receptor 4 (CXCR4) have been shown to impact cancer progression. Accumulating evidence suggests that CXCR4 and SDF-1α expression is useful for evaluating the risk of gastric cancer progression. Thus, combined analysis of SDF-1α and CXCR4 should have high prognostic potential as a molecular marker for gastric cancer.

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Background: Cold dry air provocation is useful for evaluating nonspecific nasal hyperreactivity. However, there is no research on nasal volume and dimensions after cold dry air provocation. In this respect, acoustic rhinometry is a useful tool in objectively assessing nasal cavity volume and dimension.

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