587 research outputs found

    Theory of heterotic SIS Josephson junctions between single- and multi-gap superconductors

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    Using the functional integral method, we construct a theory of heterotic SIS Josephson junctions between single- and two-gap superconductors. The theory predicts the presence of in-phase and out-of-phase collective oscillation modes of superconducting phases. The former corresponds to the Josephson plasma mode whose frequency is drastically reduced for ±\pm s-wave symmetry, and the latter is a counterpart of Leggett's mode in Josephson junctions. We also reveal that the critical current and the Fraunhofer pattern strongly depend on the symmetry type of the two-gap superconductor

    Ambegaokar-Baratoff relations of Josephson critical current in heterojunctions with multi-gap superconductors

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    An extension of the Ambegaokar-Baratoff relation to a superconductor-insulator-superconductor (SIS) Josephson junction with multiple tunneling channels is derived. Appling the resultant relation to a SIS Josephson junction formed by an iron-based (five-band) and a single-band Bardeen-Cooper-Schrieffer (BCS) type superconductors, a theoretical bound of the Josephson critical current (IcI_{\rm c}) multiplied by the resistance of the junction (RnR_{\rm n}) is given. We reveal that such a bound is useful for identifying the pairing symmetry of iron-pnictide superconductors. One finds that if a measured value of IcRnI_{\rm c}R_{\rm n} is smaller than the bound then the symmetry is ±s\pm s-wave, and otherwise ss-wave without any sign changes. In addition, we stress that temperature dependence of IcRnI_{\rm c}R_{\rm n} is sensitive to the difference of the gap functions from the BCS type gap formula in the above heterojunction.Comment: 7 pages, 6 figure

    Two-staged treatment strategy in patients with severe carotid or cerebrovascular diseases undergoing coronary artery bypass grafting.

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    Purpose : There is no clear consensus on how to treat patients undergoing coronary artery bypass grafting (CABG) who have severe concomitant carotidcerebral artery stenosis. The aim of this study was to evaluate our surgical results in patients with severe carotid and/or cerebrovascular disease undergoing CABG. Methods :Between October 2003 and April 2009, a total of 47 such patients were treated at our institution with the following strategies: (1) protective carotid artery stenting for severe carotid stenosis performed either before (n = 20) or after (n = 5) CABG or (2) a superficial temporal artery-middle cerebral artery anastomosis procedure followed by CABG if indicated (n = 4). Off-pump CABG was performed in 75% of the patients. Results. There were no major perioperative strokes or in-hospital deaths; however, three patients had transient ischemic attacks and two had minor strokes during the early post-CABG period. All of the patients with postoperative cerebrovascular events had had unilateral carotid artery occlusion. There were no late deaths during the follow-up period (up to 6 years, with a mean of 27 months). However, major adverse cardiocerebrovascular events (MACCE) occurred in seven patients (14.9%). The rates of freedom from MACCE at 1 and 3 years were 92% and 74%, respectively. Conclusion :It appears that our two-staged approach is safe and may reduce the risk of postoperative cerebrovascular events

    トランスフェリンを介する鉄の細胞内取り込み機序 ―特に肝細胞への取り込みにおける内皮細胞の関与について―

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    Transferrin (Tf) is thought to play a pivotal role in iron metabolism of various kinds of cells. Tf has specific receptors on the surface of the cells that require iron. Tf-receptor binding is followed by internalization through a system of coated pits and vesicles. The rapid decline of pH of these vesicles leads to the release and sequestration of iron by the cell. Apotransferrin-receptor complex returns to the cell surface, where under neutral pH conditions, apotransferrin is dissociated from the receptor. Recent advances in cellular and molecular biology, gene cloning and monoclonal antibody technique have elucidated many features of these processes at a molecular level. These advances are briefly reviewed, and particularly, our own observations concerning endothelial mediation of uptake of Tf by hepatocytes are discussed.トランスフェリン(Tf)は鉄代謝において重要な役割を担っている。鉄を必要とする細胞の表面には,Tfの特異的受容体が存在し,Ffは受容体との結合に引き続いて,coated pitsとcoated vesiclesを介して細胞内に取り込まれる(internalization)。Vesicle内での急速なpHの低下にともない,鉄はTfから分離し,細胞内で分画される。一方,鉄を失ったTf(アポTf)は受容体と結合したまま細胞表面にもどり,中性のpHのもとで受容体から解離する。最近の細胞・分子生物学の進歩,遺伝子クローニング,ならびにモノクローナル抗体の開発により,分子レベルで鉄代謝経路が解明されつつある。今回,これまでの主要な知見をまとめ,特に,最近筆者らの研究により明らかとなった,肝の鉄代謝における内皮細胞の役割について考察した

    Causal Role of Neural Signals Transmitted From the Frontal Eye Field to the Superior Colliculus in Saccade Generation

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    The frontal eye field (FEF) and superior colliculus (SC) are major and well-studied components of the oculomotor system. The FEF sends strong projections to the SC directly, and neurons in these brain regions transmit a variety of signals related to saccadic eye movements. Electrical microstimulation and pharmacological manipulation targeting the FEF or SC affect saccadic eye movements. These data suggest the causal contribution of each region to saccade generation. To understand how the brain generates behavior, however, it is critical not only to identify the structures and functions of individual regions, but also to elucidate how they interact with each other. In this review article, we first survey previous works that aimed at investigating whether and how the FEF and SC interact to regulate saccadic eye movements using electrophysiological and pharmacological techniques. These works have reported what signals FEF neurons transmit to the SC and what roles such signals play in regulating oculomotor behavior. We then highlight a recent attempt of our own that has applied an optogenetic approach to stimulate the neural pathway from the FEF to the SC in nonhuman primates. This study has shown that optogenetic stimulation of the FEF-SC pathway is sufficiently effective not only to modulate SC neuron activity, but also to evoke saccadic eye movements. Although the oculomotor system is a complex neural network composed of numbers of cortical and subcortical regions, the optogenetic approach will provide a powerful strategy for elucidating the role of each neural pathway constituting this network

    TinyMT32 Pseudorandom Number Generator (PRNG) (RFC 8682)

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    RFC 8682, Standards Track, TSVWG (Transport Area) working group of IETF (Internet Engineering Task Force), https://www.rfc-editor.org/rfc/rfc8682.htmlThis document describes the TinyMT32 Pseudorandom Number Generator (PRNG), which produces 32-bit pseudorandom unsigned integers and aims at having a simple-to-use and deterministic solution. This PRNG is a small-sized variant of the Mersenne Twister (MT) PRNG. The main advantage of TinyMT32 over MT is the use of a small internal state, compatible with most target platforms that include embedded devices, while keeping reasonably good randomness that represents a significant improvement compared to the Park-Miller Linear Congruential PRNG. However, neither the TinyMT nor MT PRNG is meant to be used for cryptographic applications

    Dynamic Behavior of RS latches using FIB processing and probe connection

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    PUF (Physically Unclonable Function) technologies attract attention as a candidate to prevent counterfeit chips. A latch PUF is known as a high performance PUF among various types of proposed PUFs. In this paper we describe an experiment on a dynamic attack to a latch PUF consisting of RS latches, such as measuring the latch output by a probe connection after a FIB (Focused Ion Beam) processing. As a result, we confirmed that the latch PUF using the RS latch has a tolerance for the dynamic analysis, because the RS latch output was influenced and changed by the FIB processing in our experiment
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