4,145 research outputs found

    Interspecific differences in the larval performance of Pieris butterflies (Lepidoptera: Pieridae) are associated with differences in the glucosinolate profiles of host plants

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    The tremendous diversity of plants and herbivores has arisen from a coevolutionary relationship characterized by plant defense and herbivore counter adaptation. Pierid butterfly species feed on Brassicales plants that produce glucosinolates as a chemical deterrent against herbivory. In turn, the larvae of pierids have nitrile specifier proteins (NSPs) that are expressed in their gut and disarm glucosinolates. Pierid butterflies are known to have diversified in response to glucosinolate diversification in Brassicales. Therefore, each pierid species is expected to have a spectrum of host plants characterized by specific glucosinolate profiles. In this study, we tested whether the larval performance of different Pieris species, a genus in Pieridae (Lepidoptera: Pieridae), was associated with plant defense traits of putative host plants. We conducted feeding assays using larvae of three Pieris species and 10 species of the Brassicaceae family possessing different leaf physical traits and glucosinolate profile measurements. The larvae of Pieris rapae responded differently in the feeding assays compared with the other two Pieris species. This difference was associated with differences in glucosinolate profiles but not with variations in physical traits of the host plants. This result suggests that individual Pieris species are adapted to a subset of glucosinolate profiles within the Brassicaceae. Our results support the idea that the host ranges of Pieris species depend on larval responses to glucosinolate diversification in the host species, supporting the hypothesis of coevolution between butterflies and host plants mediated by the chemical arms race

    Room temperature ferromagnetic behavior in the hollandite-type titanium oxide

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    A hollandite-type K(x)Ti(8)O(16) polycrystalline sample has been prepared and studied by magnetization, resistivity and x-ray photoelectron spectroscopy (XPS). Room temperature ferromagnetic behavior is observed in the magnetic hysteresis measurement. The sample shows a semiconductive temperature dependence in the resistivity measurement. Analysis of the Ti 2p(3/2) core-level XPS spectrum indicates that the titanium ions have a mixed valence of Ti(4+) and Ti(3+). In addition, the valence band spectrum reveals that the 3d electrons tend to localize on Ti(3+) ions in the hollandite-type TiO(2) lattice. Also, analysis of the valence band spectrum shows that the prepared sample is a wide-gap oxide with a band gap of 3.6 eV. These results indicate that the present hollandite-type K(x)Ti(8)O(16) sample can be classified as a TiO(2)-based wide-gap semiconductor with Curie temperature above room temperature. Room temperature ferromagnetism (RTFM) decreases in the sample prepared under a strong reducing gas atmosphere, accompanied with the decrease in the resistivity. The results imply that the localized 3d electrons are responsible for the RTFM of the K(x)Ti(8)O(16) sample

    Designing Secure Ethereum Smart Contracts: A Finite State Machine Based Approach

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    The adoption of blockchain-based distributed computation platforms is growing fast. Some of these platforms, such as Ethereum, provide support for implementing smart contracts, which are envisioned to have novel applications in a broad range of areas, including finance and Internet-of-Things. However, a significant number of smart contracts deployed in practice suffer from security vulnerabilities, which enable malicious users to steal assets from a contract or to cause damage. Vulnerabilities present a serious issue since contracts may handle financial assets of considerable value, and contract bugs are non-fixable by design. To help developers create more secure smart contracts, we introduce FSolidM, a framework rooted in rigorous semantics for designing con- tracts as Finite State Machines (FSM). We present a tool for creating FSM on an easy-to-use graphical interface and for automatically generating Ethereum contracts. Further, we introduce a set of design patterns, which we implement as plugins that developers can easily add to their contracts to enhance security and functionality

    Differential requirements of MyD88 and TRIF pathways in TLR4-mediated immune responses in murine B cells

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    LPS stimulates the TLR4/Myeloid differentiation protein-2 (MD-2) complex and promotes a variety ofimmune responses in B cells. TLR4 has two main signaling pathways, MyD88 and Toll/IL-1R (TIR)-domain-containing adaptor-inducing interferon- (TRIF) pathways, but relatively few studies have examinedthese pathways in B cells. In this study, we investigated MyD88- or TRIF-dependent LPS responses inB cells by utilizing their knockout mice. Compared with wild-type (WT) B cells, MyD88−/−B cells weremarkedly impaired in up-regulation of CD86 and proliferation induced by lipid A moiety of LPS. TRIF−/−Bcells were also impaired in these responses compared with WT B cells, but showed better responses thanMyD88−/−B cells. Regarding class switch recombination (CSR) elicited by lipid A plus IL-4, MyD88−/−B cells showed similar patterns of CSR to WT B cells. However, TRIF−/−B cells showed the impaired inthe CSR. Compared with WT and MyD88−/−B cells, TRIF−/−B cells exhibited reduced cell division, fewerIgG1+cells per division, and decreased activation-induced cytidine deaminase (Aicda) mRNA expressionin response to lipid A plus IL-4. Finally, IgG1 production to trinitrophenyl (TNP)-LPS immunization wasimpaired in TRIF−/−mice, while MyD88−/−mice exhibited increased IgG1 production. Thus, MyD88 andTRIF pathways differently regulate TLR4-induced immune responses in B cells

    Capacitive micromachined ultrasonic transducers with novel membrane design

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    AbstractThis paper presents a novel membrane design for capacitive micromachined ultrasonic transducers (cMUTs). The proposed design is composed of a thick membrane with reinforcing beams supported by a circumferential thin membrane to improve transducer sensitivity without degrading the membrane resonance frequency. Analytical formulation of sensitivity for the proposed design was newly derived and its validity was verified by finite element analysis (FEA). From the analysis, we confirmed that this thick membrane structure achieved three times higher sensitivity compared to the conventional design by decreasing 70 % of the mass of the thick membrane part with keeping the resonance frequency same

    Temperature-dependence of spin-polarized transport in ferromagnet / unconventional superconductor junctions

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    Tunneling conductance in ferromagnet / unconventional superconductor junctions is studied theoretically as a function of temperatures and spin-polarization in feromagnets. In d-wave superconductor junctions, the existence of a zero-energy Andreev bound state drastically affects the temperature-dependence of the zero-bias conductance (ZBC). In p-wave triplet superconductor junctions, numerical results show a wide variety in temperature-dependence of the ZBC depending on the direction of the magnetic moment in ferromagnets and the pairing symmetry in superconductors such as pxp_{x}, pyp_{y} and px+ipyp_{x}+ip_{y}-wave pair potential. The last one is a promising symmetry of Sr2_2RuO4_4. From these characteristic features in the conductance, we may obtain the information about the degree of spin-polarization in ferromagnets and the direction of the dd-vector in triplet superconductors

    The extraction of nuclear sea quark distribution and energy loss effect in Drell-Yan experiment

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    The next-to-leading order and leading order analysis are performed on the differential cross section ratio from Drell-Yan process. It is found that the effect of next-to-leading order corrections can be negligible on the differential cross section ratios as a function of the quark momentum fraction in the beam proton and the target nuclei for the current Fermilab and future lower beam proton energy. The nuclear Drell-Yan reaction is an ideal tool to study the energy loss of the fast quark moving through cold nuclei. In the leading order analysis, the theoretical results with quark energy loss are in good agreement with the Fermilab E866 experimental data on the Drell-Yan differential cross section ratios as a function of the momentum fraction of the target parton. It is shown that the quark energy loss effect has significant impact on the Drell-Yan differential cross section ratios. The nuclear Drell-Yan experiment at current Fermilab and future lower energy proton beam can not provide us with more information on the nuclear sea quark distribution.Comment: 17 pages, 4 figure
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