327 research outputs found

    Experimental Study on Fire Resistance Performance of a Hollow Slab Using a Lightweight Hollow Sphere

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    This study evaluates the fire resistance performance (1–2h) of a reinforced concrete (RC) structure-void slab using a lightweight hollow sphere, which can reduce the unnecessary dynamic of removing the central concrete. For this experiment, we set up the depth of the concrete cover, live load, and span length as the factors. The result comes out with 50 mm cover depth of the RC structure hollow slab secured. It was shown that 120 minutes of fire resistance performance can be secured regardless of the length of the structure and loading. Among these factors, the resisting capability changes more sensitively with the live load rather than the thickness of cover. The shorter span in length could assure better fire resistance performance

    Experimental Study on the Fire Resistance Performance of Prestressed Composite Beam with Corrugated Web under Standard Fire with Loading Condition

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    In this study, fire resistance tests were performed on a conventional slim floor beam and a prestressed composite beam with corrugated webs, which is suitable for a long-span structure with a reduction in story height by utilizing the prestress and accordion effect. In the fire test program, the ISO 834 standard fire curve was adopted. Key test variables were the effect of prestress, shape of corrugated webs, and thickness of sprayed fireproofing material. All of the test specimens demonstrated enhanced fire resistance performance exceeding the expected performance level. The prestressed composite beams with corrugated webs especially showed excellent fire performance, considering these specimens had thin fireproofing thickness compared to the conventional slim floor specimen

    Characterization of GDP-mannose Pyrophosphorylase from Escherichia Coli O157:H7 EDL933 and Its Broad Substrate Specificity

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    GDP-mannose pyrophosphorylase gene (ManC) of Escherichia coli (E. coli) O157 was cloned and expressed as a highly soluble protein in E. coli BL21 (DE3). The enzyme was subsequently purified using hydrophobic and ion exchange chromatographies. ManC showed very broad substrate specificities for four nucleotides and various hexose-1-phosphates, yielding ADP-mannose, CDP-mannose, UDP-mannose, GDP-mannose, GDP-glucose and GDP-2-deoxy-glucose

    Treatment for the Lumbosacral Soft Tissue Defect after Spine Surgery

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    The lumbosacral area is one of the most frequently operated spine regions because of the prevalence of disease in that area. Although a lumbosacral soft tissue defect after surgery due to inflammation and other causes is rare, such soft tissue defects are difficult to treat. Therefore, suitable methods for treating lumbosacral soft tissue defects are necessary. Therefore, this study introduces a case-treated with a transverse lumbosacral rotational flap

    Indoor formaldehyde removal over CMK-3

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    The removal of formaldehyde at low concentrations is important in indoor air pollution research. In this study, mesoporous carbon with a large specific surface area was used for the adsorption of low-concentration indoor formaldehyde. A mesoporous carbon material, CMK-3, was synthesized using the nano-replication method. SBA-15 was used as a mesoporous template. The surface of CMK-3 was activated using a 2N H2SO4 solution and NH3 gas to prepare CMK-3-H2SO4 and CMK-3-NH3, respectively. The activated samples were characterized by N2 adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. The formaldehyde adsorption performance of the mesoporous carbons was in the order of CMK-3-NH3 > CMK-3-H2SO4 > CMK-3. The difference in the adsorption performance was explained by oxygen and nitrogen functional groups formed during the activation process and by the specific surface area and pore structure of mesoporous carbon

    Large Oncocytic Adrenocortical Tumor with Uncertain Malignant Potential

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    Oncocytoma is a neoplasm consisting of oncocytes that is found in the salivary gland, kidney, and thyroid. Adrenocortical oncocytoma is particularly uncommon, and most cases reported are benign and nonfunctioning. Here, we report a 20 cm adrenal mass associated with necrosis that was identified as an oncocytic adrenocortical tumor with uncertain malignant potential through histopathological evaluation after its resection

    Estrogen receptor-α gene haplotype is associated with primary knee osteoarthritis in Korean population

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    Estrogen and estrogen receptors (ERs) are known to play important roles in the pathophysiology of osteoarthritis (OA). To investigate ER-α gene polymorphisms for its associations with primary knee OA, we conducted a case–control association study in patients with primary knee OA (n = 151) and healthy individuals (n = 397) in the Korean population. Haplotyping analysis was used to determine the relationship between three polymorphisms in the ER-α gene (intron 1 T/C, intron 1 A/G and exon 8 G/A) and primary knee OA. Genotypes of the ER-α gene polymorphism were determined by PCR followed by restriction enzyme digestion (PvuII for intron 1 T/C, XbaI for intron 1 A/G, and BtgI for exon 8 G/A polymorphism). There was no significant difference between primary knee OA patients and healthy control individuals in the distribution of any of the genotypes evaluated. However, we found that the allele frequency for the exon 8 G/A BtgI polymorphism (codon 594) was significantly different between primary knee OA patients and control individuals (odds ratio = 1.38, 95% confidence interval = 1.01–1.88; P = 0.044). In haplotype frequency estimation analysis, there was a significant difference between primary knee OA patients and control individuals (degrees of freedom = 7, χ(2 )= 21.48; P = 0.003). Although the number OA patients studied is small, the present study shows that ER-α gene haplotype may be associated with primary knee OA, and genetic variations in the ER-α gene may be involved in OA
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