409 research outputs found

    Two stochastic models for simulation of correlated random processes

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    Mathematical models for simulation of correlated stochastic processes with stationary Gaussian propertie

    Palladium-Catalyzed Amination of Unprotected Five-Membered Heterocyclic Bromides

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    An efficient method for the palladium-catalyzed amination of unprotected bromoimidazoles and bromopyrazoles is presented. The transformation is facilitated by the use of our newly developed Pd precatalyst based on the bulky biarylphosphine ligand tBuBrettPhos (L4). The mild reaction conditions employed allow for the preparation of a broad scope of aminoimidazoles and aminopyrazoles in moderate to excellent yields.National Institutes of Health (U.S.) (Award GM58160)Astellas USA Foundation (Fellowship)Japan Society for the Promotion of Science (Young Scientist Research Fellowship

    Classification of three generation models by orbifolding magnetized T2×T2T^2 \times T^2

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    We study orbifolding by the Z2(per)\mathbb{Z}_2^{\rm (per)} permutaion of T12×T22T^2_1 \times T^2_2 with magnetic fluxes and its twisted orbifolds. We classify the possible three generation models which lead to non-vanishing Yukawa couplings on the magnetized T12×T22T^2_1 \times T^2_2 and orbifolds including the Z2(per)\mathbb{Z}_2^{\rm (per)} permutation and Z2(t)\mathbb{Z}_2^{\rm (t)} twist. We also study the modular symmetry on such orbifold models. As an illustrating model, we examine the realization of quark masses and mixing angles.Comment: 31 page

    Spontaneous Extraskeletal Osteosarcoma in the Stomach of an Aged F344 Rat

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    Extraskeletal osteosarcoma is a very rare tumor in humans and animals including rats. This paper describes a case of extraskeletal osteosarcoma observed in the glandular stomach of an aged female Fischer 344 rat. Grossly, a whitish solid mass was observed at the greater curvature of the glandular stomach. Histologically, the tumor consisted of both atypical polygonal and pleomorphic spindle-shaped cells, with pleomorphic nuclei, and it contained variable amounts of osteoids and small clumps of mature bone tissue. In addition, mitotic figures were frequently observed. Neither invasion of the muscle layer or vessels in the stomach nor metastasis to distant organs was detected. There were no skeletal tumors in the body. Immunohistochemically, the tumor cells were positive for osteocalcin, osteonectin, vimentin and S-100 protein. Judging from these results, the present tumor was diagnosed as extraskeletal osteosarcoma. This is the first report of spontaneous extraskeletal osteosarcoma arising from the stomach in a rat

    Human artificial chromosome with a conditional centromere for gene delivery and gene expression.

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    Human artificial chromosomes (HACs), which carry a fully functional centromere and are maintained as a single-copy episome, are not associated with random mutagenesis and offer greater control over expression of ectopic genes on the HAC. Recently, we generated a HAC with a conditional centromere, which includes the tetracycline operator (tet-O) sequence embedded in the alphoid DNA array. This conditional centromere can be inactivated, loss of the alphoid(tet-O) (tet-O HAC) by expression of tet-repressor fusion proteins. In this report, we describe adaptation of the tet-O HAC vector for gene delivery and gene expression in human cells. A loxP cassette was inserted into the tet-O HAC by homologous recombination in chicken DT40 cells following a microcell-mediated chromosome transfer (MMCT). The tet-O HAC with the loxP cassette was then transferred into Chinese hamster ovary cells, and EGFP transgene was efficiently and accurately incorporated into the tet-O HAC vector. The EGFP transgene was stably expressed in human cells after transfer via MMCT. Because the transgenes inserted on the tet-O HAC can be eliminated from cells by HAC loss due to centromere inactivation, this HAC vector system provides important novel features and has potential applications for gene expression studies and gene therapy

    Complete Genetic Correction of iPS Cells From Duchenne Muscular Dystrophy

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    Human artificial chromosome (HAC) has several advantages as a gene therapy vector, including stable episomal maintenance that avoids insertional mutations and the ability to carry large gene inserts including the regulatory elements. Induced pluripotent stem (iPS) cells have great potential for gene therapy, as such cells can be generated from the individual's own tissues, and when reintroduced can contribute to the specialized function of any tissue. As a proof of concept, we show herein the complete correction of a genetic deficiency in iPS cells derived from Duchenne muscular dystrophy (DMD) model (mdx) mice and a human DMD patient using a HAC with a complete genomic dystrophin sequence (DYS-HAC). Deletion or mutation of dystrophin in iPS cells was corrected by transferring the DYS-HAC via microcell-mediated chromosome transfer (MMCT). DMD patient- and mdx-specific iPS cells with the DYS-HAC gave rise to differentiation of three germ layers in the teratoma, and human dystrophin expression was detected in muscle-like tissues. Furthermore, chimeric mice from mdx-iPS (DYS-HAC) cells were produced and DYS-HAC was detected in all tissues examined, with tissue-specific expression of dystrophin. Therefore, the combination of patient-specific iPS cells and HAC-containing defective genes represents a powerful tool for gene and cell therapies

    カワラヨモギとオトコヨモギ(キク科)の自然雑種集団とその生物学的位置

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