109 research outputs found

    Ratioless full-complementary 12-transistor static random access memory for ultra low supply voltage operation

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    In this study, a ratioless full-complementary 12-transistor static random access memory (SRAM) was developed and measured to evaluate its operation under an ultra low supply voltage range. The ratioless SRAM design concept enables a memory cell design that is free from the consideration of the static noise margin (SNM). Furthermore, it enables a SRAM function without the restriction of transistor parameter (W/L) settings and the dependence on the variability of device characteristics. The test chips that include both conventional 6-transistor SRAM cells and the ratioless full-complementary 12-transistor SRAM cells were developed by a 180 nm CMOS process to compare their stable operations under an ultralow supply voltage condition. The measured results show that the ratioless full-complementary 12-transistor SRAM has superior immunity to device variability, and its inherent operating ability at the supply voltage of 0.22 V was experimentally confirmed

    A capsidless ssRNA virus hosted by an unrelated dsRNA virus

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    Viruses typically encode the capsid that encases their genome, while satellite viruses do not encode a replicase and depend on a helper virus for their replication1. Here, we report interplay between two RNA viruses, yado-nushi virus 1 (YnV1) and yado-kari virus 1 (YkV1), in a phytopathogenic fungus, Rosellinia necatrix2. YkV1 has a close phylogenetic affinity to positive-sense, single-stranded (+)ssRNA viruses such as animal caliciviruses3, while YnV1 has an undivided double-stranded (ds) RNA genome with a resemblance to fungal totiviruses4. Virion transfection and infectious full-length cDNA transformation has shown that YkV1 depends on YnV1 for viability, although it probably encodes functional RNA-dependent RNA polymerase (RdRp). Immunological and molecular analyses have revealed trans-encapsidation of not only YkV1 RNA but also RdRp by the capsid protein of the other virus (YnV1), and enhancement of YnV1 accumulation by YkV1. This study demonstrates interplay in which the capsidless (+)ssRNA virus (YkV1), hijacks the capsid protein of the dsRNA virus (YnV1), and replicates as if it were a dsRNA virus

    A novel quadripartite dsRNA virus isolated from a phytopathogenic filamentous fungus, Rosellinia necatrix

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    AbstractHere we report the biological and molecular attributes of a novel dsRNA virus isolated from Rosellinia necatrix, a filamentous phytopathogenic fungus. The virus, termed Rosellinia necatrix quadrivirus 1 (RnQV1), forms rigid spherical particles approximately 45nm in diameter in infected mycelia. The particles contain 4 dsRNA segments, dsRNA1 to dsRNA4, with a size range of 4.9 to 3.7kbp, each possessing a single large ORF. A comparison of the virus-infected and -cured isogenic fungal strains suggested that RnQV1 infection has no appreciable phenotypic effects. Phylogenetic analysis using the dsRNA3-encoded RdRp sequence revealed that RnQV1 is more distantly related to quadripartite chrysoviruses than to monopartite totiviruses, and is placed in a distinct group from other mycoviruses. No significant sequence similarities were evident between known proteins and RnQV1 structural proteins shown to be encoded by dsRNA2 or dsRNA4. These suggest that RnQV1 is a novel latent virus, belonging to a new family

    Dynamical mass generation of a two-component fermion in Maxwell-Chern-Simons QED_3: The lowest ladder approximation

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    Dynamical mass generation of a two-component fermion in QED3QED_3 with a Chern-Simons term is investigated by solving the Schwinger-Dyson equation formulated in the lowest ladder approximation. Dependence of the dynamical fermion mass on a gauge-fixing parameter, a gauge coupling constant, and a topological mass is examined by approximated analytical and also numerical methods. The inclusion of the Chern-Simons term makes impossible to choose a peculiar gauge in which a wave function renormalization is absent. The numerical evaluation shows that the wave function renormalization is fairly close to 1 in the Landau gauge. It means that this gauge is still a specific gauge where the Ward-Takahashi identity is satisfied approximately. We also find that the dynamical mass is almost constant if the topological mass is larger than the coupling constant, while it decreases when the topological mass is comparable to or smaller than the coupling constant and tends to the value in QED3QED_3 without the Chern-Simons term.Comment: 22 pages, 9 figures, Version to appear in Phys. Rev.

    Diverse Partitiviruses From the Phytopathogenic Fungus,Rosellinia necatrix

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    Partitiviruses (dsRNA viruses, familyPartitiviridae) are ubiquitously detected in plants and fungi. Although previous surveys suggested their omnipresence in the white root rot fungus,Rosellinia necatrix, only a few of them have been molecularly and biologically characterized thus far. We report the characterization of a total of 20 partitiviruses from 16R. necatrixstrains belonging to 15 new species, for which "Rosellinia necatrix partitivirus 11-Rosellinia necatrix partitivirus 25" were proposed, and 5 previously reported species. The newly identified partitiviruses have been taxonomically placed in two genera,Alphapartitivirus, andBetapartitivirus. Some partitiviruses were transfected into reference strains of the natural host,R. necatrix, and an experimental host,Cryphonectria parasitica, using purified virions. A comparative analysis of resultant transfectants revealed interesting differences and similarities between the RNA accumulation and symptom induction patterns ofR. necatrixandC. parasitica. Other interesting findings include the identification of a probable reassortment event and a quintuple partitivirus infection of a single fungal strain. These combined results provide a foundation for further studies aimed at elucidating mechanisms that underly the differences observed

    Variation in bradyrhizobial NopP effector determines symbiotic incompatibility with Rj2-soybeans via effector-triggered immunity

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    The soybean Rj2 gene encodes a TIR-NBS-LRR protein that confers resistance to nodulation by certain rhizobial strains. Here, the authors show that T3SS effector NopP is an avirulence protein that is necessary for Bradyrhizobium diazoefficiens USDA 122 to trigger Rj2-dependent incompatibility

    Induction of inverted morphology in brain organoids by vertical-mixing bioreactors

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    上下動撹拌培養装置を用いた流体制御により誘導した反転型脳オルガノイド 脳オルガノイド誘導の流体シミュレーションと流体力学的理解. 京都大学プレスリリース. 2021-10-27.How you mix cells changes the brain. 京都大学プレスリリース. 2021-10-28.Organoid technology provides an opportunity to generate brain-like structures by recapitulating developmental steps in the manner of self-organization. Here we examined the vertical-mixing effect on brain organoid structures using bioreactors and established inverted brain organoids. The organoids generated by vertical mixing showed neurons that migrated from the outer periphery to the inner core of organoids, in contrast to orbital mixing. Computational analysis of flow dynamics clarified that, by comparison with orbital mixing, vertical mixing maintained the high turbulent energy around organoids, and continuously kept inter-organoid distances by dispersing and adding uniform rheological force on organoids. To uncover the mechanisms of the inverted structure, we investigated the direction of primary cilia, a cellular mechanosensor. Primary cilia of neural progenitors by vertical mixing were aligned in a multidirectional manner, and those by orbital mixing in a bidirectional manner. Single-cell RNA sequencing revealed that neurons of inverted brain organoids presented a GABAergic character of the ventral forebrain. These results suggest that controlling fluid dynamics by biomechanical engineering can direct stem cell differentiation of brain organoids, and that inverted brain organoids will be applicable for studying human brain development and disorders in the future

    A Role of Aromatase in Sjögren Syndrome

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    Several autoimmune diseases are known to develop in postmenopausal women. However, the mechanism by which estrogen deficiency influences autoimmunity is unknown. Aromatase is a converting enzyme from androgens to estrogens. In the present study, we used female aromatase gene knockout (ArKO) mice as a model of estrogen deficiency to investigate the molecular mechanism that underlies the onset and development of autoimmunity. Histological analyses showed that inflammatory lesions in the lacrimal and salivary glands of ArKO mice increased with age. Adoptive transfer of spleen cells or bone marrow cells from ArKO mice into recombination activating gene 2 knockout mice failed to induce the autoimmune lesions. Expression of mRNA encoding proinflammatory cytokines and monocyte chemotactic protein-1 (MCP-1) increased in white adipose tissue (WAT) of ArKO mice and was significantly higher than that in wild-type mice. Moreover, an increased number of inflammatory M-1 macrophage was observed in WAT of ArKO mice. A significantly increased MCP-1 mRNA expression of the salivary gland tissue in ArKO was found together with adiposity. Furthermore, the autoimmune lesions in a murine model of Sjögren’s syndrome (SS) were exacerbated by administration of an aromatase inhibitor. These results suggest that aromatase may play in a key role in the pathogenesis of SS-like lesions by controlling the target organ and adipose tissue-associated macrophage
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