2,046 research outputs found
A Robust and Low-Complexity Timing Synchronization Algorithm for ADSRC System
In this paper, a robust, low-complexity timing synchronization algorithm suitable for 5.9 GHz Dedicated Short Range Communications (DSRC) system is proposed. The proposed method uses cross-correlation technique to detect the starting point of both a short training symbol and the guard interval of the first long training symbol. This allows the proposed algorithm to have low-complex architecture. Compared to the scheme proposed by Chang and Kelly, the proposed algorithm attains considerably higher timing synchronization performance and significantly reduced computational complexity. Simulation results show that the proposed algorithm is robust and efficient in high-mobility environments and low signal-to-noise ratio (SNR) conditions
Intravaginal Administration of Fc-Fused IL7 Suppresses the Cervicovaginal Tumor by Recruiting HPV DNA Vaccine-Induced CD8 T Cells
Purpose: The induction of tissue-localized virus-specific CD8 T-cell response is essential for the development of an effective therapeutic vaccine against genital diseases, such as cervical cancer and genital herpes. Here, we aimed to elucidate the immunologic role of IL7 in the induction of mucosal cellular immunity. Experimental Design: IL7 was engineered through Fc fusion to enhance mucosal delivery across the genital epithelial barrier. The immunomodulatory role of IL7 was evaluated by monitoring the kinetics of various immune cells and measuring the expression of chemokines and cytokines after intravaginal administration of Fc-fused IL7 (IL7-Fc). The antitumor effects of intramuscular human papillomavirus (HPV) DNA vaccine or topical IL7-Fc alone or in a combinational regimen on mice survival were compared using a orthotopic cervical cancer model. Results: Intravaginal treatment of IL7-Fc, but not native IL7, induces upregulation of chemokines (CXCL10, CCL3, CCL4, and CCL5), cytokines (IFN-gamma, TNF alpha, IL6, and IL1 beta), and an adhesion molecule (VCAM-1) in the genital tract, leading to the recruitment of several leukocytes, including CD4, CD8, gamma delta T cells, and dendritic cells. Importantly, in this murine cervical cancer model, topical administration of IL7-Fc after intramuscular HPV DNA vaccination increases the number of HPV-specific CD8 T cells in the genital mucosa, but not in the spleen, leading to stronger antitumor activity than the HPV DNA vaccine alone. Conclusions: Our findings provide an important insight into the immunomodulatory role of IL7-Fc via topical application and the design of therapeutic vaccine regimen that induces effective genital-mucosal CD8 T-cell responses.1110Ysciescopu
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FIH-1, a novel interactor of mindbomb, functions as an essential anti-angiogenic factor during zebrafish vascular development
Objective: It has been shown that Mindbomb (Mib), an E3 Ubiquitin ligase, is an essential modulator of Notch signaling during development. However, its effects on vascular development remain largely unknown
Terahertz metamaterials on flexible polypropylene substrate
The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; García Meca, C.; Martínez Abietar, AJ. (2014). Terahertz metamaterials on flexible polypropylene substrate. Plasmonics. 9(5):1143-1147. https://doi.org/10.1007/s11468-014-9724-1S1143114795Smith DR, Padilla WJ, Vier DC, Nemat-Nasser SC, Schultz S (2000) Composite medium with simultaneously negative permeability and permittivity. Phys Rev Lett 84:4184–4187Pendry JB (2000) Negative refraction makes a perfect lens. Phys Rev Lett 85:3966–3969Zhang X, Liu Z (2008) Superlenses to overcome the diffraction limit. Nat Mater 7:435–441Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Schurig D, Mock JJ, Justice BJ, Cummer SA, Pendry JB, Starr AF, Smith DR (2006) Metamaterial electromagnetic cloak at microwave frequencies. Science 314:977–980Rodríguez-Cantó PJ, Martínez-Marco M, Rodríguez-Fortuño FJ, Tomás-Navarro B, Ortuño R, Peransí-Llopis S, Martínez A (2011) Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon. Opt Express 19:7664–7672Rodríguez-Fortuño FJ, Martínez-Marco M, Tomás-Navarro B, Ortuño R, Martí J, Martínez A, Rodríguez-Cantó PJ (2011) Highly-sensitive chemical detection in the infrared regime using plasmonic gold nanocrosses. Appl Phys Lett 98:133118O’Hara FJ, Singh R, Brener I, Smirnova E, Han J, Taylor AJ, Zhang W (2008) Thin-film sensing with planar terahertz metamaterials: sensitivity and limitations. Opt Express 16:1786–1795Tao H, Landy NI, Bingham CM, Zhang X, Averitt RD, Padilla WJ (2008) A metamaterial absorber for the terahertz regime: design, fabrication and characterization. Opt Express 16:7181–7188Iwaszczuk K, Strikwerda AC, Fan K, Zhang X, Averitt RD, Jepsen PU (2012) Flexible metamaterial absorbers for stealth applications at terahertz frequencies. Opt Express 20:635–643Tao H, Bingham CM, Strikwerda AC, Pilon D, Shrekenhamer D, Landy NI, Fan K, Zhang X, Padilla WJ, Averitt RD (2008) Highly flexible wide angle of incidence terahertz metamaterial absorber: design, fabrication, and characterization. Phys Rev B 78:241103(R)Tao H, Bingham CM, Pilon D, Fan K, Strikwerda AC, Shrekenhamer D, Padilla WJ, Zhang X, Averitt RD (2010) A dual band terahertz metamaterial absorber. J Phys D: Appl Phys 43:225102Padilla WJ, Taylor AJ, Highstrete C, Lee M, Averitt RD (2006) Dynamical electric and magnetic metamaterial response at terahertz frequencies. Phys Rev Lett 96:107401Chen HT, Padilla WJ, Zide JMO, Gossard AC, Taylor AJ, Averitt RD (2006) Active terahertz metamaterial devices. Nature 444:597–600Chen HT, O’Hara FJ, Azad AK, Taylor AJ, Averitt RD, Shrekenhamer DB, Padilla WJ (2008) Experimental demonstration of frequency-agile terahertz metamaterials. Nature Photon 2:295–298Chen HT, Padilla WJ, Zide JMO, Bank SR, Gossard AC, Taylor AJ, Averitt RD (2007) Ultrafast optical switching of terahertz metamaterials fabricated on ErAs/GaAs nanoisland superlattices. Opt Lett 32:1620–1622Chen HT, Palit S, Tyler T, Bingham CM, Zide JMO, O’Hara FJ, Smith DR, Gossard AC, Averitt RD, Padilla WJ, Jokerst NM, Taylor AJ (2008) Hybrid metamaterials enable fast electrical modulation of freely propagating terahertz waves. Appl Phys Lett 93:091117Chen HT, Padilla WJ, Cich MJ, Azad AK, Averitt RD, Taylor AJ (2009) A metamaterial solid-state terahertz phase modulator. Nat Photon 3:148Driscoll T, Andreev GO, Basov DN, Palit S, Cho SY, Jokerst NM, Smith DR (2007) Tuned permeability in terahertz split-ring resonators for devices and sensors. Appl Phys Lett 91:062511Debus C, Bolivar PH (2007) Frequency selective surfaces for high sensitivity terahertz sensing. Appl Phys Lett 91:184102Al-Naib IAI, Jansen C, Koch M (2008) Thin-film sensing with planar asymmetric metamaterial resonators. Appl Phys Lett 93:083507Leonhardt U, Philbin TG (2010) Geometry and light: the science of invisibility. Dover, MineolaDi Falco A, Ploschner M, Krauss TF (2010) Flexible metamaterials at visible wavelengths. New J Phys 12:113006Tao H, Strikwerda AC, Fan K, Bingham CM, Padilla WJ, Zhang X, Averitt RD (2008) Terahertz metamaterials on free-standing highly-flexible polyimide substrates. Appl Phys 41:232004Tao H, Amsden JJ, Strikwerda AC, Fan K, Kaplan DL, Zhang X, Averitt RD, Omenetto FJ (2010) Metamaterial silk composites at terahertz frequencies. Adv Mater 22:3527–3531Chen ZC, Han NR, Pan ZY, Gong YD, Chong TC, Hong MH (2011) Tunable resonance enhancement of multi-layer terahertz metamaterials fabricated by parallel laser micro-lens array lithography on flexible substrates. Opt Mat Express 1:151–157Miyamaru F, Takeda MW, Taima K (2009) Characterization of terahertz metamaterials fabricated on flexible plastic films: toward fabrication of bulk metamaterials in terahertz region. Appl Phys Express 2:042001Peralta XG, Wanke MC, Arrington CL, Williams JD, Brener I, Strikwerda A, Averitt RD, Padilla WJ, Smirnova W, Taylor AJ, O’Hara FJ (2009) Large-area metamaterials on thin membranes for multilayer and curved applications at terahertz and higher frequencies. Appl Phys Lett 94:161113Choi M, Lee SH, Kim Y, Kang SB, Shin J, Kwak MH, Kang KY, Lee YH, Park N, Min B (2011) A terahertz metamaterial with unnaturally high refractive index. Nature 470:369–373Han NR, Chen ZC, Lim CS, Ng B, Hong MH (2011) Broadband multi-layer terahertz metamaterials fabrication and characterization on flexible substrates. Opt Express 19:6990–6998Aznabet M, Navarro-Cia N, Kuznetsov SA, Gelfand AV, Fedorinina NI, Goncharov YG, Beruete M, Mrabet OE, Sorolla M (2008) Polypropylene-substrate-based SRR- and CSRR- metasurfaces for submillimeter waves. Opt Express 16:18312–18319Padilla WJ, Aronsson MT, Highstrete C, Lee M, Taylor AJ, Averitt RD (2007) Electrically resonant terahertz metamaterials: theoretical and experimental investigations. Phys Rev B 75:041102(R)Chen HT, O’Hara FJ, Taylor AJ, Averitt RD, Highstrete C, Lee M, Padilla WJ (2007) Complementary planar terahertz metamaterials. Opt Express 15:1084–1095Pendry JB, Holden AJ, Robbins DJ, Stewart WJ (1999) Magnetism from conductors and enhanced nonlinear phenomena. IEEE Trans Microwave Theory Tech 47:2075–208
Preparation and thermal conductivity of CuO nanofluid via a wet chemical method
In this article, a wet chemical method was developed to prepare stable CuO nanofluids. The influences of synthesis parameters, such as kinds and amounts of copper salts, reaction time, were studied. The thermal conductivities of CuO nanofluids were also investigated. The results showed that different copper salts resulted in different particle morphology. The concentration of copper acetate and reaction time affected the size and shape of clusters of primary nanoparticles. Nanofluids with different microstructures could be obtained by changing the synthesis parameters. The thermal conductivities of CuO nanofluids increased with the increase of particle loading
Zigzag-shaped nickel nanowires via organometallic template-free route
In this manuscript, the formation of nickel nanowires (average size: several tens to hundreds of μm long
and 1.0-1.5 μm wide) at low temperature is found to be driven by dewetting of liquid organometallic
precursors during spin coating process and by self-assembly of Ni clusters. Elaboration of metallic thin
films by low temperature deposition technique makes the preparation process compatible with most of the
substrates. The use of iron and cobalt precursor shows that the process could be extended to other metallic
systems. In this work, AFM and SEM are used to follow the assembly of Ni clusters into straight or
zigzag lines. The formation of zigzag structure is specific to the Ni precursor at appropriate preparation
parameters. This template free process allows a control of anisotropic structures with homogeneous sizes
and angles on standard Si/SiO2 surface
Shortcuts to adiabaticity in a time-dependent box
A method is proposed to drive an ultrafast non-adiabatic dynamics of an
ultracold gas trapped in a box potential. The resulting state is free from
spurious excitations associated with the breakdown of adiabaticity, and
preserves the quantum correlations of the initial state up to a scaling factor.
The process relies on the existence of an adiabatic invariant and the inversion
of the dynamical self-similar scaling law dictated by it. Its physical
implementation generally requires the use of an auxiliary expulsive potential
analogous to those used in soliton control. The method is extended to a broad
family of many-body systems. As illustrative examples we consider the ultrafast
expansion of a Tonks-Girardeau gas and of Bose-Einstein condensates in
different dimensions, where the method exhibits an excellent robustness against
different regimes of interactions and the features of an experimentally
realizable box potential.Comment: 6 pp, 4 figures, typo in Eq. (6) fixe
Metabolic analysis of the interaction between plants and herbivores
Insect herbivores by necessity have to deal with a large arsenal of plant defence metabolites. The levels of defence compounds may be increased by insect damage. These induced plant responses may also affect the metabolism and performance of successive insect herbivores. As the chemical nature of induced responses is largely unknown, global metabolomic analyses are a valuable tool to gain more insight into the metabolites possibly involved in such interactions. This study analyzed the interaction between feral cabbage (Brassica oleracea) and small cabbage white caterpillars (Pieris rapae) and how previous attacks to the plant affect the caterpillar metabolism. Because plants may be induced by shoot and root herbivory, we compared shoot and root induction by treating the plants on either plant part with jasmonic acid. Extracts of the plants and the caterpillars were chemically analysed using Ultra Performance Liquid Chromatography/Time of Flight Mass Spectrometry (UPLCT/MS). The study revealed that the levels of three structurally related coumaroylquinic acids were elevated in plants treated on the shoot. The levels of these compounds in plants and caterpillars were highly correlated: these compounds were defined as the ‘metabolic interface’. The role of these metabolites could only be discovered using simultaneous analysis of the plant and caterpillar metabolomes. We conclude that a metabolomics approach is useful in discovering unexpected bioactive compounds involved in ecological interactions between plants and their herbivores and higher trophic levels.
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