707 research outputs found

    Axion dark matter search using the storage ring EDM method

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    We propose using the storage ring EDM method to search for the axion dark matter induced EDM oscillation in nucleons. The method uses a combination of B and E-fields to produce a resonance between the g2g-2 spin precession frequency and the background axion field oscillation to greatly enhance sensitivity to it. An axion frequency range from 10910^{-9} Hz to 100 MHz can in principle be scanned with high sensitivity, corresponding to an faf_a range of 101310^{13} GeV fa1030\leq f_a \leq 10^{30} GeV, the breakdown scale of the global symmetry generating the axion or axion like particles (ALPs)

    Change in gene expression of mouse embryonic stem cells derived from parthenogenetic activation

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    BACKGROUND We previously established parthenogenetic mouse embryonic stem cells (ESCs) and this study was subsequently conducted for elucidating the influence of oocyte parthenogenesis on gene expression profile of ESCs. METHODS Gene expression of parthenogenetic ESC (pESC)-1 or pESC-2 was separately compared with that of two normally fertilized ESC (nfESC) lines (B6D2F1 and R1 strains), and quantification of mRNA expression was conducted for validating microarray data. RESULTS In two sets of comparison, reaction of 11 347 and 15 454 gene probes were altered by parthenogenesis, while strain difference changed the expression of 15 750 and 14 944 probes. Level of correlation coefficient was higher in the comparisons between normal fertilization and parthenogenesis (0.974-0.985) than in the comparisons between strains of nfESCs (0.97-0.971). Overall, the expression of 3276-3329 genes was changed after parthenogenesis, and 88% (96/109) of major functional genes differentially (P < 0.01) expressed in one comparison set showed the same change in the other. When we monitored imprinted genes, expression of nine paternal and eight maternal genes were altered after parthenogenesis and 88% (14/16) of these was confirmed by mRNA quantification. CONCLUSIONS The change in gene expression after parthenogenesis was similar to, or less than, the change induced by a strain difference under a certain genetic background. These results may suggest the clinical feasibility of parthenogenesis-derived, pluripotent cell

    The cortical activation pattern by a rehabilitation robotic hand: a functional NIRS study

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    Introduction: Clarification of the relationship between external stimuli and brain response has been an important topic in neuroscience and brain rehabilitation. In the current study, using functional near infrared spectroscopy (fNIRS), we attempted to investigate cortical activation patterns generated during execution of a rehabilitation robotic hand. Methods: Ten normal subjects were recruited for this study. Passive movements of the right fingers were performed using a rehabilitation robotic hand at a frequency of 0.5 Hz. We measured values of oxy-hemoglobin (HbO), deoxy-hemoglobin (HbR) and total-hemoglobin (HbT) in five regions of interest: the primary sensory-motor cortex (SM1), hand somatotopy of the contralateral SM1, supplementary motor area (SMA), premotor cortex (PMC), and prefrontal cortex (PFC). Results: HbO and HbT values indicated significant activation in the left SM1, left SMA, left PMC, and left PFC during execution of the rehabilitation robotic hand (uncorrected, p &lt; 0.01). By contrast, HbR value indicated significant activation only in the hand somatotopic area of the left SM1 (uncorrected, p &lt; 0.01). Conclusions: Our results appear to indicate that execution of the rehabilitation robotic hand could induce cortical activation. © 2014 Chang, Lee, Gu, Lee, Jin, Yeo, Seo and Jang.1

    Surface Characteristics of Orthodontic Materials and Their Effects on Adhesion of Mutans streptococci

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    Objective: To test the hypothesis that there are no significant differences in the adhesion of mutans streptococci (MS) to various orthodontic materials based on their surface characteristics. Materials and Methods: Surface roughness (SR) and surface free energy (SFE) characteristics were investigated for nine different orthodontic materials (four orthodontic adhesives, three bracket raw materials, hydroxyapatite blocks, and bovine incisors) using confocal laser scanning microscopy and sessile drop method. Each material, except the bovine incisors, was incubated with whole saliva or phosphate-buffered saline for 2 hours. Adhesion assays were performed by incubating tritium-labeled MS with each material for 3 or 6 hours. Results: Orthodontic adhesives had higher SFE characteristics and lower SR than bracket materials. Orthodontic adhesives showed a higher MS retaining capacity than bracket materials, and MS adhesion to resin-modified glass ionomer and hydroxyapatite was highest. Extended incubation time increased MS adhesion, while saliva coating did not significantly influence MS adhesion. SFE, specifically its dispersive and polar components, was positively correlated with MS adhesion, irrespective of saliva coating. Conclusions: The hypothesis is rejected. This study suggests that SFE characteristics play an important role in the initial MS adhesion to orthodontic materials.This study was supported by a grant from the Korea Health 21 Project, Ministry of Health and Welfare, Republic of Korea (03-PJ1-PG1-CH09-0001)

    Change in gene expression of mouse embryonic stem cells derived from parthenogenetic activation

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    We previously established parthenogenetic mouse embryonic stem cells (ESCs) and this study was subsequently conducted for elucidating the influence of oocyte parthenogenesis on gene expression profile of ESCs

    The Effect of Differential Modulation of the N-methyl-D-aspartate Receptor on Growth and intracellular Calcium Ion Concentration in Normal Human Oral Keratinocytes

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    The purpose of this study was to examine the interaction between the agents [N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOS-I)] and cultured normal human oral keratinocytes (NHOK) in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. We also examined whether AA and NOS-I could protect NHOK from glutamate cytotoxicity and the change of intracellular calcium ion concentration. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. Cell viability was measured by the MTT assay and DNA synthesis by the BrdU assay. The microscopic features of NHOK were observed and changes in intracellular calcium ion concentration were measured. NMDA and NNA induced an initial increase in cell number. Low concentration of AA induced an increase in cell number while high concentrations of AA induced a decrease in cell number. The decrease in cell number induced by NMDA at the seventh day was abolished by the addition of low concentrations of AA or NOS inhibitors. Low concentrations of AA or NMDA with high concentrations of AA significantly increased the DNA synthesis rate at four hours. NMDA and AA both induced an increase in intracellular calcium ion concentration, and AA enhanced NMDA-induced intracellular calcium ion in a concentration-dependent manner. NMDA-induced NHOK death was associated with intracellular calcium ion change and the promotion of cell differentiation. Low concentrations of AA protected NHOK cells from NMDA-induced death.

    A simple and accurate SNP scoring strategy based on typeIIS restriction endonuclease cleavage and matrix-assisted laser desorption/ionization mass spectrometry

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    <p>Abstract</p> <p>Background</p> <p>We describe the development of a novel matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)-based single nucleotide polymorphism (SNP) scoring strategy, termed Restriction Fragment Mass Polymorphism (RFMP) that is suitable for genotyping variations in a simple, accurate, and high-throughput manner. The assay is based on polymerase chain reaction (PCR) amplification and mass measurement of oligonucleotides containing a polymorphic base, to which a typeIIS restriction endonuclease recognition was introduced by PCR amplification. Enzymatic cleavage of the products leads to excision of oligonucleotide fragments representing base variation of the polymorphic site whose masses were determined by MALDI-TOF MS.</p> <p>Results</p> <p>The assay represents an improvement over previous methods because it relies on the direct mass determination of PCR products rather than on an indirect analysis, where a base-extended or fluorescent report tag is interpreted. The RFMP strategy is simple and straightforward, requiring one restriction digestion reaction following target amplification in a single vessel. With this technology, genotypes are generated with a high call rate (99.6%) and high accuracy (99.8%) as determined by independent sequencing.</p> <p>Conclusion</p> <p>The simplicity, accuracy and amenability to high-throughput screening analysis should make the RFMP assay suitable for large-scale genotype association study as well as clinical genotyping in laboratories.</p

    Development of a Mobile Application, “Wild Flowers of Bukhansan National Park (version 1.0)”, for Identification of Plants in Bukhansan National Park

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    AbstractWe developed the educational purpose mobile application, named “Wild Flowers of Bukhansan National Park (version 1.0)”, aiming for easy identification of wildflowers for students and visitors in the park. When visitors find a flower or part of plant in the park, visitors can search for its name utilizing the pictures and characters provided in their own smartphone mobile devices or tablet PCs. The application provides pictures of wildflowers in the park and character-based searching system based on 12 diagnostic features (e.g., growth form, leaf arrangement, flower symmetry, petal color, petal number, sepal number, etc). We adopted the complete floristic survey of Chung and Lee (1962) and added species that we confirmed their distribution in the park during the development of this application. In summary, number of vascular plants in this park was estimated to be 428 taxa including 100 families, 280 genera, 327 species, 1 subspecies, 50 varieties, and 5 formas. We provided a total of 588 pictures representing 358 taxa and each taxon includes multiple pictures in many cases. Included identification quizzes can be an efficient educational tool as well as fun activity for students and visitors who are learning plant species in Korea. Our next step will include GPS function in the application for indicating visitor's location and for providing previously reported sites of the species that we interested in the map of the park. The future application which includes GPS function will be a valuable tool for the monitoring of rare plants, plant researches related to the climate changes, etc. We currently provide Korean iPhone version only, and English version and both of android versions will be serviced soon
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