6,137 research outputs found

    Spin polarization amplification within nonmagnetic semiconductors at room temperature

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    We demonstrate theoretically that the spin polarization of current can be electrically amplified within nonmagnetic semiconductors by exploiting the fact the spin current, compared to the charge current, is weakly perturbed by electric driving forces. As a specific example, we consider a T-shaped current branching geometry made entirely of a nonmagnetic semiconductor, where the current is injected into one of the branches (input branch) and splits into the other two branches (output branches). We show that when the input current has a moderate spin polarization, the spin polarization in one of the output branches can be higher than the spin polarization in the input branch and may reach 100% when the relative magnitudes of current-driving electric fields in the two output branches are properly tuned. The proposed amplification scheme does not use ferromagnets or magnetic fields, and does not require low temperature operation, providing an efficient way to generate a highly spin polarized current in nonmagnetic semiconductors at room temperature.Comment: 11 pages, 2 figures, to appear in Phys. Rev.

    52-GHz Millimetre-Wave PLL Synthesizer

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    Effect of Brand Familiarity and Brand Loyalty on Imagery Elaboration in Online Apparel Shopping

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    Imagery elaboration is defined as the activation of store information in the production of mental images beyond what is provided by the stimulus (Babin & Burns, 1998, p. 266). When consumers virtually experience or evaluate apparel products, imagery elaboration could be evoked through various features provided by online retailers. Previous studies examined te positive effect of evoked imagery elaboration on attitudinal reponses toward the brand and toward the ad in advertisements (Babin & Burns, 1998; Ellen & Bone, 1991). Due to the limitatin of virtual product experience may play an important role to help consumers imagine or evaluate features, fnctions, or usages of apparel products

    Ballistic spin field-effect transistors: Multichannel effects

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    We study a ballistic spin field-effect transistor (SFET) with special attention to the issue of multi-channel effects. The conductance modulation of the SFET as a function of the Rashba spin-orbit coupling strength is numerically examined for the number of channels ranging from a few to close to 100. Even with the ideal spin injector and collector, the conductance modulation ratio, defined as the ratio between the maximum and minimum conductances, decays rapidly and approaches one with the increase of the channel number. It turns out that the decay is considerably faster when the Rashba spin-orbit coupling is larger. Effects of the electronic coherence are also examined in the multi-channel regime and it is found that the coherent Fabry-Perot-like interference in the multi-channel regime gives rise to a nested peak structure. For a nonideal spin injector/collector structure, which consists of a conventional metallic ferromagnet-thin insulator-2DEG heterostructure, the Rashba-coupling-induced conductance modulation is strongly affected by large resonance peaks that arise from the electron confinement effect of the insulators. Finally scattering effects are briefly addressed and it is found that in the weakly diffusive regime, the positions of the resonance peaks fluctuate, making the conductance modulation signal sample-dependent.Comment: 18 pages, 15 figure

    Peptide-enhanced mRNA transfection in cultured mouse cardiac fibroblasts and direct reprogramming towards cardiomyocyte-like cells.

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    The treatment of myocardial infarction is a major challenge in medicine due to the inability of heart tissue to regenerate. Direct reprogramming of endogenous cardiac fibroblasts into functional cardiomyocytes via the delivery of transcription factor mRNAs has the potential to regenerate cardiac tissue and to treat heart failure. Even though mRNA delivery to cardiac fibroblasts has the therapeutic potential, mRNA transfection in cardiac fibroblasts has been challenging. Herein, we develop an efficient mRNA transfection in cultured mouse cardiac fibroblasts via a polyarginine-fused heart-targeting peptide and lipofectamine complex, termed C-Lipo and demonstrate the partial direct reprogramming of cardiac fibroblasts towards cardiomyocyte cells. C-Lipo enabled the mRNA-induced direct cardiac reprogramming due to its efficient transfection with low toxicity, which allowed for multiple transfections of Gata4, Mef2c, and Tbx5 (GMT) mRNAs for a period of 2 weeks. The induced cardiomyocyte-like cells had α-MHC promoter-driven GFP expression and striated cardiac muscle structure from α-actinin immunohistochemistry. GMT mRNA transfection of cultured mouse cardiac fibroblasts via C-Lipo significantly increased expression of the cardiomyocyte marker genes, Actc1, Actn2, Gja1, Hand2, and Tnnt2, after 2 weeks of transfection. Moreover, this study provides the first direct evidence that the stoichiometry of the GMT reprogramming factors influence the expression of cardiomyocyte marker genes. Our results demonstrate that mRNA delivery is a potential approach for cardiomyocyte generation

    Electrode pooling: How to boost the yield of switchable silicon probes for neuronal recordings

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    State-of-the-art silicon probes for electrical recording from neurons have thousands of recording sites, but only a fraction of them can be used simultaneously due to the forbiddingly large volume of the associated wires. To overcome this fundamental constraint, we propose a novel method called "electrode pooling" that uses a single wire to serve multiple recording sites. Multiple electrodes are connected to a single wire through a set of controllable switches. Here we present the framework behind this method and an experimental strategy to support it. We show that under suitable conditions electrode pooling can save wires without compromising the content of the recordings. We make recommendations for the design of future devices to take advantage of this strategy

    Dispersion of Vascular Plant in Kumo-do, Korea

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    AbstractThe vascular plants observed in the area were composed of a total of 228 taxa; 72 families, 172 genus, 201 species, 25 varieties, 1 sub-species and 1 cross species. The only endangered plants found in the area were Milletia japonica (Siebold & Zucc.) A.Gray. The endemic plants growing in the Geumodo except transplanted plants were Lespedeza x maritima Nakai and Carpinus coreana Nakai. which accounted for 0.8% of the vascular plants in Geumodo, 228 taxa. Specialized plants of Geumodo were a total of 41 species; 30 taxa in Grade I, 1 taxon in Grade II, 9 taxa in Grade III and 1 taxon in Grade V. Milletia japonica (Siebold & Zucc.) A.Gray was the only species found in important Grade IV to V. Currently, ferries ply to the island, attracting many tourists. This poses a threat to the rare plants living in the island and presses down the island to develop. Therefore, in the long-term perspective, the conservation plan such as comprehensive research and monitoring on the ecosystem shall be established to protect evergreen broad-leaved forests

    Semiparametric regression analysis for alternating recurrent event data

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142558/1/sim7563_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142558/2/sim7563.pd

    An Explanatory Case Study on Passenger Service Systems Adoption: A Taiwanese Air Carrier

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    This study explains the adoption of Passenger Service Systems (PSS) in airlines through the lens of Inter-organizational Systems adoption and home-region orientation. It examined 20 causal factors influencing PSS adoption and tested an original research model in the technology–organization–environment context, by applying transactional cost theory and neo-institutional theory. Prior to a cross-case study across multiple airlines, the explanatory single-case research analyzed interview data from four informants with a Taiwanese carrier and multiple industry reports; the key findings highlight: (i) interoperable functionality and industry standards as external technological drivers strongly influenced full conversion to the PSS platform; (ii) within the organizational context, commitment to global network, organizational transformation and top management support were identified as salient internal factors in decision-making and resource allocation, while normative pressures from an alliance body exerted a stronger influence over the airline than any other isomorphic forces; and (iii) in the context of environment, full conversion was also facilitated by PSS vendors and powered by the need for mutual worldwide learning to effectively operate foreign markets from home region. This in-depth case study provides insights that PSS in a common-use environment can bring business value to PSS user airlines in accessing a broader global market, offering greater competitive services and expanding distribution channels. To increase causality and generalizability, future work involving an embedded multi-case study with three East Asian carriers will be undertaken. Available at: https://aisel.aisnet.org/pajais/vol11/iss1/2
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