291 research outputs found

    Seiberg-Witten Curve for E-String Theory Revisited

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    We discuss various properties of the Seiberg-Witten curve for the E-string theory which we have obtained recently in hep-th/0203025. Seiberg-Witten curve for the E-string describes the low-energy dynamics of a six-dimensional (1,0) SUSY theory when compactified on R^4 x T^2. It has a manifest affine E_8 global symmetry with modulus \tau and E_8 Wilson line parameters {m_i},i=1,2,...,8 which are associated with the geometry of the rational elliptic surface. When the radii R_5,R_6 of the torus T^2 degenerate R_5,R_6 --> 0, E-string curve is reduced to the known Seiberg-Witten curves of four- and five-dimensional gauge theories. In this paper we first study the geometry of rational elliptic surface and identify the geometrical significance of the Wilson line parameters. By fine tuning these parameters we also study degenerations of our curve corresponding to various unbroken symmetry groups. We also find a new way of reduction to four-dimensional theories without taking a degenerate limit of T^2 so that the SL(2,Z) symmetry is left intact. By setting some of the Wilson line parameters to special values we obtain the four-dimensional SU(2) Seiberg-Witten theory with 4 flavors and also a curve by Donagi and Witten describing the dynamics of a perturbed N=4 theory.Comment: 35 pages, 2 figures, LaTeX2

    Seiberg-Witten Curve for the E-String Theory

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    We construct the Seiberg-Witten curve for the E-string theory in six-dimensions. The curve is expressed in terms of affine E_8 characters up to level 6 and is determined by using the mirror-type transformation so that it reproduces the number of holomorphic curves in the Calabi-Yau manifold and the amplitudes of N=4 U(n) Yang-Mills theory on 1/2 K3. We also show that our curve flows to known five- and four-dimensional Seiberg-Witten curves in suitable limits.Comment: 18 pages, 1 figure; appendix C adde

    非微生物素材表面への大腸菌の初期付着を抑制する穀類抽出液の分析

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    We examined the initial attachment of E. coli to abiotic surfaces conditioned with cereal extracts. The extracts were water-soluble fractions prepared from flours of barley, quinoa, rice and wheat. Strains used were E. coli ATCC 8739, E. coli NBRC 3301, E. coli NBRC 3302, E. coli NBRC 13168, E. coli NBRC 13891, and E. coli O157:H7 sakai. When surfaces of glass and stainless steel were conditioned at 25°C for 30 min with 0.5% cereal extracts, significantly lower numbers of E. coli cells attached to the conditioned surfaces than unconditioned ones, irrespective of strains used. The highest activity in reduction of the number of E. coli cells attached to the abiotic surfaces was found in the wheat extract. The suppressive activity was stable after treatments of the extract by autoclave and enzymatic digestion with α-amylase and Proteinase K. We purified the active compound by ammonium sulfate fractionation and gel filtration with HiPrep 16/60 Sephacryl S-200 HR after the enzymatic treatments. The purified compound showed an average molecular mass of about 300 kDa by light-scattering measurements. Analyses of its components indicated that the active compound was arabinoxylan; the molar ratios were 1.0 (arabinose) to 2.46 (xylose). Commercially available arabinoxylan (average molecular mass: 370 kDa) also showed the similar activity. To our knowledge, this is the first report on a dietary fiber from cereals which suppresses the initial attachment of E. coli to abiotic surfaces

    A Scanning Tunneling Microscopy Study of Vanadium Oxide

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    Atomic resolution images of the (010) surface of a divanadiun pentoxide (V2O5) single crystal were successfully obtained by the use of a scanning tunneling microscope (STM). The images of the filled states at sample bias voltage, Vs = -2 V and the empty states at Vs = +2 V correspond to oxygen and vanadium ions, respectively. As for the vanadium ion sites, an additional peak of the electronic states at the conduction band edge due to the defects of vanadyl oxygen ions was found in the normalized conductance spectrum through the tunneling spectroscopy (TS) measurement

    Gene gun approches for DNA vaccine and cytokine gene therapy in protozoan parasite infection

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    The particle-mediated method for gene delivery with a gene gun utilizes a shock wave to accelerate DNA-coated gold particles into target cells or tissues. This gene delivery method is effective in various somatic tissues in vitro and in vivo. We have, herein, applied this gene delivery system to DNA vaccine and cytokine gene therapy for protozoan parasite infections. We used cDNA encoding 47 kDa of Plasmodium falciparum serine repeat antigen (SERA) that is a vaccine candidate antigen and did SERA DNA immunization with mice using gene gun. Significant SERA-specific antibodies (Abs) were observed by SERA DNA immunization. Furthermore, these Ab responses were enhanced and regulated by coinoculation of cytokine expression plasmid. For other application, we examined the effects of in vivo IL-12 gene treatment on the course of infection with obligate protozoa, Trypanosoma cruzi. Transfer with IL-12 expression plasmid in vivo regulated systemic immune responses and furthermore this treatment controlled the progression of experimental trypanosomiasis. Therefore, this gene gun approach may be a useful for DNA vaccine and gene therapy in a wide spectrum of diseases other than the protozoan parasite infection

    ナゼ アレルギー シッカン ワ ゾウカ シテ イルノカ : エイヨウガク ノ タチバ ヨリ

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    Allergy, in the form of atopic diseases such as atopic eczema, allergic rhinitis, and asthma, is a chronic disorder of increasing importance in the developed countries. Although several environmental exposures, including dietary factors, infection, and microflora, have been implicated in the cause of allergic diseases, these relationship remains unclear. In respect to dietary factor, one of the candidates that contribute to the disease is polyunsaturated fatty acid because many reports showed that n-3 fatty acids have property to suppress the inflammatory immune response. Therefore, it is possible that intake of fatty acids at unsuitable n-3/n-6 ratio causes the allergic disease. Other than fatty acid, it has shown that higher concentrations of vitamin E intake are associated with lower serum IgE concentration and a lower frequency of allergen sensitization

    Soy isoflavones and immunity

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    The amount of soy products consumed in Japan is much greater than that in Western countries. Recent evidence indicates that soy isoflavones play a beneficial role in obesity, cancer, osteoporosis, and cardiovascular disease. The soybean isoflavone genistein is present at high levels in soy products. Genistein is structurally similar to 17β- estradiol (E2), and genistein has been suggested to be act as E2 or an antagonist against E2. Genistein suppresses antigen-specific immune response in vivo and lymphocyte proliferation response in vitro. However, genistein enhances the cytotoxic response mediated by NK and cytotoxic T cells and the cytokine production from T cells. Thus, the effect of genistein on immunity is immune cell -dependent. Due to its unique effect on immune function, genistein has been used for the treatment of the diseases in animal models and it has been found that genistein inhibits allergic inflammatory responses. In this review, we summarize current studies related to the effect of isoflavone genistein on the immune system

    血管内皮細胞における過酸化水素誘導のカベオリン-1リン酸化に対するケルセチンの抑制効果

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    Caveolin-1 is a major protein of the caveolae structure in vascular endothelial cell membrane. Phosphorylation of caveolin-1 is one of the initial events leading to exacerbation of vascular permeability caused by oxidative stress. Although quercetin is known to be an anti-atherosclerosis factor that acts as a dietary antioxidant, little is known about its role in the regulation of caveolin-1 phosphorylation. In this study, we investigated the inhibitory effect of quercetin on hydrogen peroxide-induced caveolin-1 phosphorylation in human umbilical vein endothelial cells. Quercetin inhibited caveolin-1 phosphorylation in cells pretreated with quercetin for 24 h and then exposed to hydrogen peroxide. However, quercetin 3-O-β-glucuronide, a conjugated metabolite of quercetin, did not exert this inhibitory effect. Exposure to hydrogen peroxide increased vascular permeability and reduced mRNA expression of the intercellular adhesion protein, vascular endothelial cadherin (VE-cadherin). By contrast, pretreatment with quercetin suppressed the increase in vascular permeability and decreased VE-cadherin expression. These results indicate that deconjugated quercetin can play a role in the prevention of altered vascular permeability under oxidative stress by suppressing caveolin-1 phosphorylation. Thus, dietary quercetin may be beneficial for the maintenance of endothelial cell function

    Functional analysis of block 5, one of the highly conserved amino acid sequences in the 130-kDa CryIVA protein produced by Bacillus thuringiensis subsp. israelensis

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    AbstractThere are five amino acid sequences highly conserved among Bacillus thuringiensis δ-endotoxins. We have changed the amino acid residues in block 5, one of the conserved sequences, of CryIVA. When the amino acid residues with charged side chains were replaced by others, the amount of production of the altered CryIVA protein was markedly decreased. It is suggested that the decrease is caused by the unstable conformation of the altered CryIVA protein molecule, as judged by digestion with trypsin and thermolysin. On the other hand, the substitution of amino acid residues in block 5 did not affect the insecticidal activity of CryIVA. These results strongly suggest that block 5 of CryIVA is one of the stability-determining elements of the protoxin molecule
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