545 research outputs found

    High scale validity of the DFSZ axion model with precision

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    With the assumption of classical scale invariance at the Planck scale, the DFSZ axion model can generate the Higgs mass terms of the appropriate size through technically natural parameters and may be valid up to the Planck scale. We discuss the high scale validity of the Higgs sector, namely the absence of Landau poles and the vacuum stability. The Higgs sector is identical to that of the type-II two Higgs doublet model with a limited number of the Higgs quartic couplings. We utilize the state-of-the-art method to calculate vacuum decay rates and find that they are enhanced at most by 1010 compared with the tree level evaluation. We also discuss the constraints from flavor observables, perturbative unitarity, oblique parameters and collider searches. We find that the high scale validity tightly constrains the parameter region, but there is still a chance to observe at most about 10% deviation of the 125 GeV Higgs couplings to the fermions

    FACILE SYNTHESIS OF 2,3-DISUBSTITUTED PYRROLES FROM 2-SUBSTITUTED 1-PYRROLINES

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    2-Substituted-1-pyrrolines react with various arylaldehyde acetals in the presence of a Lewis acid and base to give 2-substituted 3-arylmethylidene-1-pyrrolines, which are transformed to 2,3-disubstituted pyrroles by base-catalyzed double-bond isomerization.ArticleHETEROCYCLES. 85(5):1187-1195 (2012)journal articl

    Dynamic X-ray Diffraction Technique for Measuring Rheo-optical Properties of Crystalline Polymeric Materials

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    A dynamic X-ray diffraction technique, which can follow the responses of polymer crystals (crystallization, orientation, and lattice deformation) to a mechanical excitation of sinusoidal strain induced to a bulk specimen, was described. The descriptions for such responses are qualitatively made by using a narrow sector technique, which can measure the X-ray diffraction intensity distribution at a particular phase angle of the sinusoidal strain as a function of static and dynamic strains, temperature, and angular frequency. A typical result is demonstrated in terms of the investigation of orientationcrystallization phenomena of natural rubber vulcanizates. More quantitative descriptions can be made by using a half-circle sector technique, which can measure the in-phase and out-of phase components of the dynamic X-ray diffraction intensity distribution. From these, one can obtain the dynamic strain-induced crystallization and orientation coefficients and the dynamic response of lattice deformation of a specific crystal plane both as functions of temperature and frequency. After a brief survey of the principle of the half-circle sector technique, frequency dependence of the dynamic strain-induced crystallization coefficients of the (002) and (200) crystal planes of natural rubber vulcanizates is demonstrated in terms of the two frequency dispersion regions around 10⁻² and 10¹ Hz at a room temperature. The former and latter dispersions must be correlated with the crystallization processes of the so-called α- and γ-filaments, respectively. In addition, frequency and temperature dispersions of the dynamic strain-induced orientation coefficient and the dynamic response of lattice deformation of the (110) crystal plane of polyethylene are demonstrated in relation to the so-called a₁ and a₂ dispersions of dynamic mechanical modulus function of this material

    Medaka: a promising model animal for comparative population genomics

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    <p>Abstract</p> <p>Background</p> <p>Within-species genome diversity has been best studied in humans. The international HapMap project has revealed a tremendous amount of single-nucleotide polymorphisms (SNPs) among humans, many of which show signals of positive selection during human evolution. In most of the cases, however, functional differences between the alleles remain experimentally unverified due to the inherent difficulty of human genetic studies. It would therefore be highly useful to have a vertebrate model with the following characteristics: (1) high within-species genetic diversity, (2) a variety of gene-manipulation protocols already developed, and (3) a completely sequenced genome. Medaka (<it>Oryzias latipes</it>) and its congeneric species, tiny fresh-water teleosts distributed broadly in East and Southeast Asia, meet these criteria.</p> <p>Findings</p> <p>Using <it>Oryzias </it>species from 27 local populations, we conducted a simple screening of nonsynonymous SNPs for 11 genes with apparent orthology between medaka and humans. We found medaka SNPs for which the same sites in human orthologs are known to be highly differentiated among the HapMap populations. Importantly, some of these SNPs show signals of positive selection.</p> <p>Conclusion</p> <p>These results indicate that medaka is a promising model system for comparative population genomics exploring the functional and adaptive significance of allelic differentiations.</p

    Cytochemical studies of the hemoglobin synthesis of erythroblasts

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    The process of hemoglobin sythesis in erythroid cells have been traced mainly by observing cells under the light of 4,060 &#197;. To scrutinize the theory of hemoglobin synthesis in the nucleus of erythroblasts, several cytochemical and morphological observations were also carried out. The conclusions derived from them are as follows: 1 The absorption at 4,060 &#197; of the cell, which indicates the location of heme, appeared in the nucleus as early as in the develpmental stage of basophilic erythroblasts. The absorption of hcme in cytoplasm likewise appeared in this stage showing nearly the same intensity of the absorption. The absorption picture of heme in the nucleus, which is coincidental with that of interchromatin, increased along with the progess of maturation as well as in the cytoplasm. The absorption in the nucleus disappeared at the orthochromatic stage where the picture of interchromatin disappeared, while the intensity of absorption in the cytoplasm continued to increase till the stage of reticulocyte. 2 The pseudoperoxidase reaction of hemoglobin, the appearance of acidophlic protein and masked lipids detectable in the location of hemoglobin gave an exactly identical picture with that of the absorption of heme in the nucleus as well as in the cytoplasm. 3 Permeability test performed by supravital staining with Nile blue revealed that the nucleus of erythroblasts from the basophilic to the orthorchromatic stages has increased its permeability being stained selectively as in the case of dead cells. 4 The mitochondria and the endoplasmic reticulum proved to be retained well in the entire course of hemoglobin synthesis, even after the denucleation, the reticulocyte stage. From these observations the authors believe that the hemoglobin syntheis will take place in the cytoplasm throughout the life cycle of erythroid cells, pointing out that the absorption picturebf heme appearing in the nucleus will be in all likelihood due to the infusion of the hemoglobin from the cytoplasm.</p

    Cyclin A2-CDK2 regulates embryonic gene activation in 1-cell mouse embryos

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    AbstractRecruitment of maternal mRNA in mice appears essential for embryonic gene activation (EGA) that is initiated in the 1-cell stage. The identity of which recruited mRNAs is responsible, however, is not known. We report here that recruitment of cyclin A2 mRNA may be critical for EGA. Cyclin A2 protein accumulates in pronuclei between 6 and 12 h after fertilization, the time when EGA is initiated. This cyclin A2 may be generated from maternally recruited cyclin A2 mRNA because its accumulation was inhibited by 3′-deoxyadenosine, which inhibits mRNA polyadenylation. When CDK2 activity or pronuclear accumulation of cyclin A2 was inhibited with CDK2 inhibitors or by microinjected siRNAs, respectively, DNA replication was not inhibited but the increase of transcriptional activity was prevented. In addition, microinjection of recombinant cyclin A2-CDK2 protein increased transcriptional activity. Cyclin A2-CDK2 is activated following egg activation, because an increase in phosphorylation of retinoblastoma protein was observed using antibodies that recognize site-specific phosphorylation catalyzed by this kinase and treatment with a CDK2 inhibitor or microinjection with cyclin A2 siRNAs prevented the increase in retinoblastoma protein phosphorylation. These results suggest that recruitment of maternal cyclin A2 mRNA following egg activation is linked to EGA

    Adverse Influences of Antimicrobial Strategy against Mature Oral Biofilm

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    Antimicrobial measures, such as topical antiseptics and local drug delivery, have proven effective as complements to mechanical control. However, recent investigations have reported some adverse influences of antimicrobial strategy
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