• Polymer(Korea)
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• v.38 no.6
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• pp.815-819
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• 2014

Scaffolds of tissue engineering should be biocompatible and biodegradable for cell attachment, proliferation and differentiation. In the various scaffold fabrication, 3D printing technique can make the three dimensional scaffold with interconnected pores for cell ingrowth. Polycaprolactone (PCL) is biodegradable polyester with a low melting temperature and has been approved by the Food and Drug Administration (FDA). In this study, PCL scaffold was fabricated by 3D bioprinting system and surface modification of PCL scaffold was controlled by NaOH treatment. Morphological change and wetability of NaOH-treated scaffold were observed by SEM and contact angle measurement system. The remnant of PCL treated with NaOH was measured by ATR-FTIR. In vitro study of scaffolds was evaluated with WST-1 and ALP activity assay. NaOH treatment of PCL scaffolds increased surface roughness, hydrophilicity, cell proliferation and osteogenic differentiation. These results indicate that NaOH-treated PCL scaffold made by 3D bioprinting has tissue engineered potential for the development of biocompatible material.

• The Mathematical Education
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• v.52 no.4
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• pp.483-496
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• 2013

In this study, we investigated the structure of the mathematics education scholars' co-authorship relationship in papers registered at the National Research Foundation of Korea by social network analysis. The data were 354 scholars from 257 papers in 4 journals from 2009 to 2013 based on 'the 2009 revised Korean National Curriculum'. For the analysis, Pajek3 and UCINET6.3 were used. The results of this study were as follows: First, each of the mathematics education scholars is connected on average with about 5 paths of intermediate collaborators. Second, Analyses of the first component group found distinguishable scholar groups' characteristics depending on their affiliations, majors, and job statuses. Third, there were scholars having high values in network degree centrality measures despite not having high numbers in published papers. On the contrary, there sere scholars having high numbers in published papers despite not having high values in network analysis. Finally, I suggested the directions for the future research with the limitations of this study.

• BMB Reports
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• v.36 no.1
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• pp.20-27
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• 2003

Dihaloalkanes constitute an important group of chemicals because of their widespread use in industry and agriculture and their potential for causing toxicity and cancer. Chronic toxic effects are considered to depend upon bioactivation, either by oxidation or thiol conjugation. Considerable evidence links genotoxicity and cancer with glutathione conjugations reactions, and some aspects of the mechanisms have been clarified with 1,2-dihaloalkanes and dihalomethanes. Recently the DNA repair protein $O^6$-alkylguanine transferase has been shown to produce cytotoxicity and genotoxicity by mans of a thiol-dependent process with similarities to the glutathione reactions.

• Analytical Science and Technology
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• v.8 no.4
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• pp.715-722
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• 1995

The structural characterization for series of polyesters has been done by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Polymer fragments and intact oligomers composed of large numbers of repeat units have been investigated. Transesterification of polyesters in trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CFA) was monitored and reaction products were identified using TOF-SIMS. The shapes and intensities of clusters in transesterification spectra show good agreement with the theoretical isotope pattern. TOF-SIMS spectra were used to obtain information about the progress of the transesterification reaction.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.527-532
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• 2008

As therapeutic uses of radionuclides in nuclear medicine increases, the use of patient-specific methods for calculation of radiation dose becomes more important. In this manuscript basic methods and resources for internal dose calculations are outlined, with a focus on how current changes and advances are making more accurate and detailed, patient-individualized dose calculations possible. Most current resources make use of standardized models of the human body representing median individuals, but the use of image-based and more realistic models will soon take their place, and will permit adjustments to represent individual patients and tailor therapy planning uniquely for each subject.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.1-18
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• 2022

Drug-drug interactions are a major cause of hospitalization and deaths related to drug use. A large fraction of these is due to inhibition of enzymes involved in drug metabolism and transport, particularly cytochrome P450 (P450) enzymes. Understanding basic mechanisms of enzyme inhibition is important, particularly in terms of reversibility and the use of the appropriate parameters. In addition to drug-drug interactions, issues have involved interactions of drugs with foods and natural products related to P450 enzymes. Predicting drug-drug interactions is a major effort in drug development in the pharmaceutical industry and regulatory agencies. With appropriate in vitro experiments, it is possible to stratify clinical drug-drug interaction studies. A better understanding of drug interactions and training of physicians and pharmacists has developed. Finally, some P450s have been the targets of drugs in some cancers and other disease states.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5829-5833
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• 2014

Background: The role of processed meat in the aetiology of squamous cell oesophageal cancer has been explored in detail. Methods: In the time period 1990-2005, a case-control study was conducted in Montevideo, Uruguay including 2,368 participants (876 cases of oesophageal cancer and 1,492 controls). Relative risks, approximated by the odds ratios, were estimated by multiple unconditional logistic regression. Results: Processed meat was positively associated with oesophageal cancer (upper quartile vs lower quartile OR 2.30, 95%CI 1.72-3.07), whereas salted meat intake was positively associated with squamous cell oesophageal cancer (OR 3.82, 95%CI 2.74-5.33). Finally other cured meats were positively associated with oesophageal cancer (OR 1.65, 95%CI 1.22-2.22). Conclusions: It could be concluded that processed meat consumption could be an important risk factor for the aetiology of squamous cell oesophageal cancer in Uruguay.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.113-123
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• 2017

In human reliability analysis, dependence assessment is an important issue in risky large complex systems, such as operation of a nuclear power plant. Many existing methods depend on an expert's judgment, which contributes to the subjectivity and restrictions of results. Recently, a computational method, based on the Dempster-Shafer evidence theory and analytic hierarchy process, has been proposed to handle the dependence in human reliability analysis. The model can deal with uncertainty in an analyst's judgment and reduce the subjectivity in the evaluation process. However, the computation is heavy and complicated to some degree. The most important issue is that the existing method is in a positive aspect, which may cause an underestimation of the risk. In this study, a new evidential analytic hierarchy process dependence assessment methodology, based on the improvement of existing methods, has been proposed, which is expected to be easier and more effective.

• BMB Reports
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• v.32 no.1
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• pp.92-97
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• 1999

Cytokinesis and septation should be coordinated to nuclear division in the cell division cycle for precise transmission of the genome into daughter cells. byr4, an essential gene in fission yeast Schizosaccharomyces pombe, regulates the timing of cytokinesis and septation in a dosage-dependent manner. We examined the intracellular localization of the Byr4 protein by expressing byr4 as a fusion of green fluorescence protein (GFP). The Byr4 protein localizes as a single dot on the nuclear periphery of interphase cells, duplicates before mitosis, and the duplicated dots segregate with the nuclei in anaphase. The behavior of Byr4p throughout the cell cycle strongly suggests that Byr4p is localized to the spindle pole body (SPB), a microtubule organizing center (MTOC) in yeast. The presence of the Byr4 protein in the SPB is consistent with its function to coordinate mitosis and cytokinesis. We also mapped the domains of Byr4p for its proper localization to SPB by expressing various byr4 deletion mutants as GFP fusions. Analyses of the diverse byr4 deletion mutants suggest that the indirect repeats and the regions homologous to the open reading frame (ORF) YJR053W of S. cerevisiae in its C-terminus are essential for its localization to the SPB.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.728-733
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• 2014

Background Periareolar Augmentation Mastopexy is one of the most challenging operations in plastic surgery. Problems with scar quality, areolar widening, and distortion are frequent problems that interfere with a predictable result. Methods A retrospective review was performed on fifty consecutive patients who underwent a periareolar augmentation mastopexy with the interlocking approach. Of the 50 patients, 30 had both preoperative and postoperative photographs and were the basis of the study. Results The age of the patients ranged from 19 to 56 years with the average age being 39 years. The postoperative follow-up averaged 9.5 months and the implants averaged 316 mL. There were no deaths, pulmonary embolism, deep vein thrombosis, or infected implants. Four patients had complications following surgery for an overall complication rate of 13%. Two patients developed an infected Gore-Tex suture. Two of these complications were treated with revision surgery. Five patients required reoperation for an overall reoperative rate of 16% (one patient was converted to a full mastopexy). Conclusions As a result of this retrospective study, we have found the interlocking approach to periareolar augmentation/mastopexy to be a safe and reliable operation.