471 research outputs found
Interplay between superconductivity and ferromagnetism in epitaxial Nb(110)/Au(111)/Co(0001) trilayers
Epitaxially grown multilayer systems offer the possibility to study the
influence of ferromagnetism on superconductivity in a new and controlled way.
In this paper, we explore how the superconducting properties of high quality,
epitaxially-grown superconductor/normal-metal/ferromagnet trilayers evolve as a
function of the exchange splitting in the ferromagnet, and the thickness of the
normal metal layer. We report results for Nb(110)/Au(111)/Co(0001), and make a
detailed comparison with earlier results for Nb(110)/Au(111)/Fe(110). We use
quantitative FFT analysis to confirm the existence of a long-period (2.1 nm)
oscillation in the superconducting transition temperature Tc as a function of
the Au-layer thickness tAu, for tAu>2 nm, and highlight an additional
short-period (0.76 nm) oscillation for tAu<3 nm in Nb/Au/Co. This short-period
oscillation can be explained in terms of a damped RKKY-like oscillation of the
spin-polarization in Au. The robustness of the long-period oscillation against
the substitution of Co for Fe suggests that it is intrinsic to the Au(111)
layer on Nb, and may represent a new form of quantum interference in very clean
trilayer systems.Comment: 23 pages, 10 figure
Interplay between superconductivity and ferromagnetism in epitaxial Nb(110)/Au(111)/Fe(110) trilayers
In order to clarify the influence of ferromagnetism on superconductivity
through a normal metal layer, the superconducting properties of epitaxial
Nb(110)/Au(111)/Fe(110) trilayers were studied as a function of the thickness
tAu of the intervening Au layer. Structural characterization of the samples
revealed sharp interfaces, almost free from roughness. A strong suppression of
the superconducting transition temperature Tc was observed for tAu<10 A,
implying a strong spin-polarization of the Au layer in the vicinity of the
Au/Fe interface. A periodic change of Tc with a period of ~21 A (~9 atomic
monolayer of Au) was observed for 20 A<tAu<104 A. Neither the Fermi surface
nesting of the normal metal layer, nor Fulde-Ferrel-Larkin-Ovchinnikov
oscillations induced by a superconducting proximity effect in the ferromagnet
can by themselves account for the observed period. These results suggest that a
new and more subtle form of quantum interference occurs in very clean trilayer
systems.Comment: 15 pages, 6 figure
Interaction between a Unique Minor Protein and a Major Capsid Protein of Bluetongue Virus Controls Virus Infectivity.
Among the Reoviridae family of double-stranded RNA viruses, only members of the Orbivirus genus possess a unique structural protein, termed VP6, within their particles. Bluetongue virus (BTV), an important livestock pathogen, is the prototype Orbivirus BTV VP6 is an ATP-dependent RNA helicase, and it is indispensable for virus replication. In the study described in this report, we investigated how VP6 might be recruited to the virus capsid and whether the BTV structural protein VP3, which forms the internal layer of the virus capsid core, is involved in VP6 recruitment. We first demonstrated that VP6 interacts with VP3 and colocalizes with VP3 during capsid assembly. A series of VP6 mutants was then generated, and in combination with immunoprecipitation and size exclusion chromatographic analyses, we demonstrated that VP6 directly interacts with VP3 via a specific region of the C-terminal portion of VP6. Finally, using our reverse genetics system, mutant VP6 proteins were introduced into the BTV genome and interactions between VP6 and VP3 were shown in a live cell system. We demonstrate that BTV strains possessing a mutant VP6 are replication deficient in wild-type BSR cells and fail to recruit the viral replicase complex into the virus particle core. Taken together, these data suggest that the interaction between VP3 and VP6 could be important in the packaging of the viral genome and early stages of particle formation.IMPORTANCE The orbivirus bluetongue virus (BTV) is the causative agent of bluetongue disease of livestock, often causing significant economic and agricultural impacts in the livestock industry. In the study described in this report, we identified the essential region and residues of the unique orbivirus capsid protein VP6 which are responsible for its interaction with other BTV proteins and its subsequent recruitment into the virus particle. The nature and mechanism of these interactions suggest that VP6 has a key role in packaging of the BTV genome into the virus particle. As such, this is a highly significant finding, as this new understanding of BTV assembly could be exploited to design novel vaccines and antivirals against bluetongue disease
Densification and Plastic Deformation under Microindentation in Silicate Glasses and the Relation to Hardness and Crack Resistance
The Compositional Variation of Microindentation Induced Densified and Plastic Deformation Volumes in Simple Silicate Glasses
性ホルモン結合グロブリン(SHBG)の代謝への影響の検討
学位の種別: 課程博士審査委員会委員 : (主査)東京大学教授 田中 廣壽, 東京大学准教授 小川 純人, 東京大学准教授 池上 恒雄, 東京大学准教授 藤城 光弘, 東京大学講師 多田 稔University of Tokyo(東京大学
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