478 research outputs found

    The mechanism of low-concentration sodium nitroprusside-mediated protection of chondrocyte death

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    Sodium nitroprusside (SNP), a widely used nitric oxide donor, has recently been shown to mediate chondrocyte apoptosis by generating reactive oxygen species, whereas more potent nitric oxide donors do not induce chondrocyte apoptosis. The present study was performed to investigate the protective effect of a low concentration of SNP upon the cytotoxicity of chondrocytes to higher concentrations of SNP, and to elucidate the underlying mechanism. Human osteoarthritis chondrocytes were cultured as monolayers, and first-passage cells were used for the experiments. Chondrocyte death induced by 1 mM SNP was completely inhibited by pretreating with 0.1 mM SNP. This protective effect of SNP was replicated by the guanosine-3',5'κ-cyclic monophosphate analog, DBcGMP. Protection from chondrocyte death conferred by 0.1 mM SNP was mediated by heme oxygenase 1 (HO-1), as was revealed by the increased expression of HO-1 in 0.1 mM SNP pretreated chondrocytes and by the reversal of this protective effect by the HO-1 inhibitor, zinc protoporphyrin. SNP-mediated chondrocyte protection correlated with the downregulation of both extracellular signal-regulated protein kinase 1/2 and p38 kinase activation. SNP at 0.1 mM induced significant NF-κB activation as revealed by electrophoretic mobility shift assays, and the inhibition of NF-κB by MG132 or Bay 11-7082 nullified 0.1 mM SNP-mediated chondrocyte protection. The upregulation of p53 and the downregulation of Bcl-(XL )and Mcl-1 by 1 mM SNP were reversed by 0.1 mM SNP pretreatment at the protein level by western blotting. Our study shows that priming with 0.1 mM SNP confers complete protection against cell death induced by 1 mM SNP in human articular chondrocytes. This protective effect was found to be correlated with the upregulation of both HO-1 and NF-κB and with the concomitant downregulation of both extracellular signal-regulated protein kinase 1/2 and p38 activation

    Cases of ethical violation in research publications: through editorial decision making process

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    Purpose – To improve and strengthen existing publication and research ethics, KODISA has identified and presented various cases which have violated publication and research ethics and principles in recent years. The editorial office of KODISA has been providing and continues to provide advice and feedback on publication ethics to researchers during peer review and editorial decision making process. Providing advice and feedback on publication ethics will ensure researchers to have an opportunity to correct their mistakes or make appropriate decisions and avoid any violations in research ethics. The purpose of this paper is to identify different cases of ethical violation in research and inform and educate researchers to avoid any violations in publication and research ethics. Furthermore, this article will demonstrate how KODISA journals identify and penalize ethical violations and strengthens its publication ethics and practices. Research design, data and methodology – This paper examines different types of ethical violation in publication and research ethics. The paper identifies and analyzes all ethical violations in research and combines them into five general categories. Those five general types of ethical violations are thoroughly examined and discussed. Results – Ethical violations of research occur in various forms at regular intervals; in other words, unethical researchers tend to commit different types of ethical violations repeatedly at same time. The five categories of ethical violation in research are as follows: (1) Arbitrary changes or additions in author(s) happen frequently in thesis/dissertation related publications. (2) Self plagiarism, submitting same work or mixture of previous works with or without using proper citations, also occurs frequently, but the most common type of plagiarism is changing the statistical results and using them to present as the results of the empirical analysis; (3) Translation plagiarism, another ethical violation in publication, is difficult to detect but occurs frequently; (4) Fabrication of data or statistical analysis also occurs frequently. KODISA requires authors to submit the results of the empirical analysis of the paper (the output of the statistical program) to prevent this type of ethical violation; (5) Mashup or aggregator plagiarism, submitting a mix of several different works with or without proper citations without alterations, is very difficult to detect, and KODISA journals consider this type of plagiarism as the worst ethical violation. Conclusions – There are some individual cases of ethical violation in research and publication that could not be included in the five categories presented throughout the paper. KODISA and its editorial office should continue to develop, revise, and strengthen their publication ethics, to learn and share different ways to detect any ethical violations in research and publication, to train and educate its editorial members and researchers, and to analyze and share different cases of ethical violations with the scholarly community

    Vortex-antivortex pair driven magnetization dynamics studied by micromagnetic simulations

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    The magnetization dynamics approaching an equilibrium vortex state from an initial nonequilibrium state under zero magnetic field in a circular shaped Fe disk with thickness of 5 nm and a diameter of 1200 nm were studied. Starting from the initial random configuration of in-plane magnetizations, a great number of vortex and antivortex pairs energetically favorable to form were generated at a lot of nucleation sites. It was found that the sites propagated and then were annihilated by their attractive interactions during the relaxation dynamic process. The study shows that temporal magnetization evolutions can be dominated by the nucleation of the vortex and antivortex pairs, followed by their propagation and annihilation.open222

    Vortex-antivortex assisted magnetization dynamics in a semi-continuous thin-film model system studied by micromagnetic simulations

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    We have studied magnetization M dynamics in a semicontinuous 33-nm -thick Fe model system, which approaches new equilibrium states under various magnetic fields, H=0, -1, -10, and -30 Oe, starting from an initial M configuration of complex microstructures experimentally observed in a real continuous Fe film. Simulation results with H=0 clearly reveal that small needle-shaped domains and ripple structures found in a frozen state of the demagnetized Fe film continue to grow far into a surrounding 180?? domain, and that zigzag folding structures appear through the M dynamic evolution assisted by vortex and antivortex. Furthermore, it is found that many domain walls of a cross-tie type exhibit their dynamic developments under H=-10 and -30 Oe, caused by interactions between vortex and antivortex states. This vortex-antivortex assisted M dynamic evolution offers deeper insights into the comprehensive understanding of the static or dynamic properties of M reversal processes as well as additional features or more details of magnetic microstructures in real continuous films.open141

    Growth Performance, Relative Meat and Organ Weights, Cecal Microflora, and Blood Characteristics in Broiler Chickens Fed Diets Containing Different Nutrient Density with or without Essential Oils

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    The present study was conducted to investigate whether dietary essential oils could affect growth performance, relative organ weights, cecal microflora, immune responses and blood profiles of broiler chickens fed on diets containing different nutrient densities. A total of eight hundred-forty 1-d-old male broiler chicks were randomly allotted into twenty-eight pens (7 pens per treatment, 30 chicks per pen). There were four experimental diets containing two different nutrient densities and supplemented with or without essential oils. Experimental period lasted for 35 days. No clear interaction between nutrient density and essential oils on any of growth performance-related parameters was observed. Live body weights were affected (p<0.05) by nutrient density at 21 days and by dietary essential oils at 35 days. Essential oils significantly (p<0.05) increased daily body weight gain and feed conversion ratio during the periods of 22 to 35 and 1 to 35 days, but failed to affect feed intake during the entire experimental period. Daily weight gain at 1 to 21 days and feed intake at 1 to 21 and 1 to 35 days were significantly impaired (p<0.05) by nutrient density. There were significant treatment interactions (p<0.05) on relative weights of bursa of Fabricius and abdominal fat contents. Finally, either essential oil or nutrient density did not influence the relative percentages of breast and leg meats, the population of cecal microflora, blood parameters and antibody titers against Newcastle disease and infectious bronchitis in broiler chickens. It was concluded that dietary essential oils, independent to nutrient density, failed to stimulate feed intake, but increased growth performance in broiler chickens

    Floristic study of Cheondeungsan Mountain in Korea

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    AbstractThe distribution of native plants of Cheondeungsan Mountain (807 m, N 37°05'00“–37°05'30”, E 128°00'0“–128°02'0”) in Chungcheongbuk-do was determined and the major flora were identified. During field investigations carried out from May 2011 to October 2011, 87 families, 254 genera, and 369 taxonomic groups (327 species, 4 subspecies, 33 varieties, and 5 forms) were confirmed, and the distribution of 219 taxonomic groups was discovered for the first time. The distribution of four endemic plants of Korea, including Ajuga spectabilis Nakai and Salvia chanryoenica Nakai, and that of Penthorum chinense Pursh, a Grade V specific plant species, was found. There were 20 taxa of naturalized plants at Cheondeungsan; the growth and development of plants that are harmful to the ecosystem, such as Ambrosia artemisiifolia L., Ambrosia trifida L., Eupatorium rugosum Houtt., and Aster pilosus Willd., was observed around the forest paths and lowlands

    Carbon nanotube diode fabricated by contact engineering with self-assembled molecules

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    The authors report the construction of carbon nanotube Schottky diodes by covering a selectively exposed area of the electrode with self-assembling molecules. Two self-assembling molecules with different polarities, 2-aminoethanethiol and 3-mercaptopropionic acid, were used to modify the Fermi level lineup at the selected contact. The devices showed p -type behavior with symmetric I-V showing clear rectifying behavior after treatment of one contact with 2-aminoethanethiol. Their experiment, in conjunction with the results of ab initio electronic structure calculations, suggests that the diode action stems from the asymmetric Fermi level lineup between the bare and engineered contacts.open131
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