2,129 research outputs found
Root-mediated signal transmission of systemic acquired resistance against above-ground and below-ground pathogens
No full textBackground and Aims Plants modulate defence signalling networks in response to various biotic stresses via inter-organ communications. The root-mediated transmission of systemic acquired resistance (SAR) against soilborne and air-borne plant pathogens from SAR-induced plants to neighbouring plants subjected to local chemical and pathogen treatments was evaluated. Methods The first two plants out of ten Nicotiana benthamiana seedlings were pre-treated with the SAR-triggering chemical benzothiadiazole (BTH). All ten seedlings were then challenged with two pathogenic bacteria, i.e. the root (bacterial wilt) pathogen Ralstonia solanacearum and the leaf (wildfire) pathogen Pseudomonas syringae pv. tabaci, at 7 d after SAR induction. Key Results Disease severity was noticeably lower in BTH-pre-treated plants than in the control. Surprisingly, two plants located next to BTH-treated plants exhibited reduced disease symptoms indicating that SAR signal transmission occurred through the root system. Determinant(s) secreted from the root system were search for and it was found that salicylic acid (SA) is a major molecule involved in SAR transmission through the root. Analysis of the expression of the defence-related genes N. benthamiana pathogenesis-related gene 1a (NbPR1a) and NbPR2 confirmed that BTH treatment elicited SAR via root-root transmission between plants. Plants with knock-down of the multiple resistance component SGT1 and SA biosynthesis-related gene ICS1 by Tobacco rattle virus-mediated virus-induced gene silencing exhibited a lack of root-mediated SAR transmission. The biological relevance of this finding was validated by challenge with the SAR-inducing avirulent pathogen P. syringae pv. syringae instead of BTH, which produced similar results. Conclusions Our findings demonstrated that SAR is transmissible through the root system from SAR-triggered plants to neighbouring plants
(C)The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Compan
Screenshots of the Smombie Guardian (SG) prototype.
No full textIn (a), each user can calibrate SG by creating a step size profile to improve the distance accuracy. When the user is about to collide with an obstacle, SG triggers a red border and a vibration (from (b) to (c)). SG extracts the contour of the obstacle based on color in (d).</p
5 similar to 6 GHz-band GaAs MESFET-based cross-coupled differential oscillator MMICs with low phase-noise performance
No full textLC-tank oscillators in the 5similar to6 GHz frequency range have been designed and implemented in a commercial 0.6 mum GaAs MESFET technology. One is a voltage-controlled oscillator (VCO), and the other is an oscillator without a controlling element. The output frequency range of the VCO is from 5.44 to 6.14 GHz, and the measured phase-noise is -101.67 dBc/Hz at an offset frequency of 600 KHz from the 5.44 GHz carrier. The phase-noise of the 6.44 GHz oscillator is -108 dBc/Hz at an offset frequency of 600 KHz, and the phase-noise curve, in the offset frequency range between 100 KHz and 1 MHz, shows a -20 dB/decade slope. These phase-noise characteristics are comparable to, or better than, those of the reported 5similar to6 GHz-band CMOS oscillators. To our knowledge, this is the first GaAs MESFET-based oscillator which has a cross-coupled differential topology and a capacitive coupling feedback to suppress the up-conversion of 1/f noise. Also, it is first reported that the GaAs MESFET-based oscillator shows 1/f(2) phase-noise behavior across the offset frequency range from 100 KHz to 1 MHz
Social and cognitive development of adolescents : some concepts, concerns and conjectures
No full textMeeting: Asian Workshop on Child and Adolescent Development, 4th, 1-7 June, 1986, Singapore, SG"Plenary session, keynote address 2
The relationship between civic attitudes and voting intention : an analysis of vocational upper secondary schools in England and Singapore
No full textFrom 2009 to 2011, a team from the Centre for Learning and Life Chances in Knowledge Economies and Societies carried out a mixedmethods study of young people in England and Singapore. With regard to civic attitudes, the study showed that there was a greater sense of political self-efficacy and collective (school) efficacy in Singapore than in England. In addition, the group in Singapore scored higher on future voting relative to the group in England. Further, while both political self-efficacy and collective (school) efficacy were correlated with future voting in England, only the latter was correlated in the case of Singapore. For some, the results may seem counter-intuitive. The article reflects on these results, particularly those relating to democratic outcomes
Experimental investigation of the temperature effect on the structural response of SG-laminated reinforced glass beams
No full textTo generate high-level redundancy for structural glass beams, a novel concept of laminating a metal reinforcement to a structural glass beam has been developed at Delft University of Technology (TU Delft). This concept makes use of the relatively stiff polymer interlayer material SentryGlas (SG) to bond the metal to the glass. However, due to the visco-elastic properties of the SG, its stiffness varies at different temperature levels. To what extent this temperature dependency has an effect on the structural response of the beam composite has been experimentally investigated in cooperation with Ghent University (UGent) and is the subject of current publication. Two separate series of pull-out tests, to investigate the bond strength, and beam tests, to investigate the post-breakage response, have been conducted at -20, 23 and 60 degrees C. The pull-out tests revealed a high temperature dependency of the bond strength of SG. This temperature dependency also had an effect on the structural response of the beams. However, regardless of temperature level all beams showed high-level plastic response and high redundancy. It is therefore concluded that temperature levels of -20 to 60 degrees C do not endanger the structural safety of SG-laminated reinforced glass beams.RESSLA
Intrinsic surface impedance of YBa2Cu3O7-delta- and SmBa2Cu3O7-delta-coated conductors measured non-invasively by using a dielectric resonator method
No full textRealization of a high critical current density (J(c)) on the order of 10(6) A/cm(2) at 77 K for long, thick, high-temperature superconductor (HTS)-coated conductors makes it possible to use the coated conductors for both small-scale and large-scale applications. YBa2Cu3O7-&delta; (YBCO)- and SmBa2Cu3O7-&delta; (SmBCO)-coated conductors with respective critical current densities (J(c)) of I X 10(6) A/cm(2) (77 K) and 1.2 X 10(6) A/cm(2) (77 K) were grown oil flexible, biaxially textured Ni tapes with a width of 10 mm and a thickness of &SIM; 70 &mu; m. The intrinsic surface resistance and the penetration depth of the coated conductors were measured using a, rutile-loaded resonator and a sapphire-loaded resonator at the respective resonant frequencies of &SIM; 8.5 GHz and &SIM; 19.5 GHz at temperatures below 90 K. Intrinsic surface resistance (R-s) values of &SIM; 440 &mu;&UOmega; and &SIM; 360 &mu;&UOmega; were observed at 77 K and &SIM; 8.5 GHz for YBCO- and SmBCO-coated conductors, respectively; these values are comparable to those for YBCO films on dielectric single-crystal substrates. The surface resistance of a 2.50 nm-thick SmBCO-coated conductor appeared to increase a little after it was wound around a 30-mm-diameter rod. Our results demonstrate the usefuluess of the dielectric resonator method for quality control of long HTS-coated conductors and the possibility of using the HTS-coated conductors for relatively small cavity resonators
Blocking TLR-TICAM-1 pathway by RSV sG
No full textMonocyte-derived dendritic cells (mDCs) recognize viral RNA extrinsically by TLR3 on the membrane and intrinsically RIG-I/MDA5 in the cytoplasm to induce type I interferons (IFNs) and mDC maturation. When mDCs were treated with live or UV-irradiated respiratory syncytial virus (RSV), early (~4 h) induction of IFN-β detected in other virus infections was barely observed. Live RSV subsequently replicated to activate the cytoplasmic IFN-inducing pathway leading to robust type I IFN induction. We found that RSV initial attachment to cells blocked polyI:C-mediated IFN-β induction, and this early IFN-β-modulating event was abrogated by Abs against envelope proteins of RSV, demonstrating the presence of a IFN-regulatory mode by early RSV attachment to host cells. By IFN-stimulated response element (ISRE) reporter analysis in HEK293 cells, polyI:C- or LPS-mediated ISRE activation was dose-dependently inhibited by live and inactive RSV to a similar extent. Of the RSV envelope proteins, simultaneously-expressed or exogenously-added RSV G or soluble G (sG) proteins inhibited TLR3/4-mediated ISRE activation in HEK293 cells. sG proteins expressed in cells did not affect the RIG-I/MDA5 pathway but inhibited the TLR adaptor TRIF/TICAM-1 pathway for ISRE activation. Finally, extrinsically-added sG protein suppressed the production of IFN-β in mDCs. Although the molecular mechanism of this extrinsic functional mode of the RSV G protein remains undetermined, G proteins may neutralize the F protein function that promotes IFN-mediated mDC modulation via TLR4 and may cause insufficient raising cell-mediated immunity against RSV
Analysis and construction status of SG-II 5PW laser facility
No full textWe present a recent progress of the SG-II 5PW facility, which designed a multi-petawatt ultrashort pulse laser based on optical parametric chirped-pulse amplification (OPCPA). The prior two optical parametric amplifiers have been accomplished and chirped pulses with an energy of 49.7 J and a full-width-at-half-maximum (FWHM) spectrum bandwidth of 85 nm have been achieved. In the PW-scale optical parametric amplification (OPA), with the pump pulse that has an energy of 118 J from the second harmonic generation of the SG-II 7th beam, the pump-to-signal conversion efficiency is up to 41.9%, which to the best of our knowledge is the highest among all of the reported values for OPCPA systems. The compressed pulse is higher than 37 J in 21 fs (1.76 PW), and the focal spot is {\sim}10~\unicode[STIX]{x03BC}\text{m} after the closed-loop corrections by the adaptive optics. Limited by the repetition of the pump laser, the SG-II 5PW facility operates one shot per hour. It has successfully been employed for high energy physics experiments.</jats:p
Preliminary survey of araceae of Sg. Rawog conservation Area, Segaliud Lokan forest researve (FMU 19B)
No full textConsidering that Sg. Rawog Conservation Area has been logged, it was thus with considerable surprise that the author encountered Rhaphidophora fluminea Ridl. along the river bank of Sg. Rawog since its first collection in 1897 from Bonggaya. Homalomena gempal Kartini, P.C Boyce and W.S Yeng was found growing on the sandstone of the river bank. Two interesting species of Schismatoglottis belong to the Trifiscata Complex were found not far from river bank of Trail 11. Alocasia princeps W. Bull and A. sarawakensis M. Hotta were found inside the forest at all trails except in the heath forest (Trail C49). Aroids climbers, namely Amydrium medium (Zoll. & Moritzi) Nicolson, Pothos sp., Rhaphidophora lativeginata M. Hotta, Scindapsus pictus Hassk. and Scindapsus sp. were found scattered in the inner area of the forest. In conclusion, the area around the river bank of Sg. Rawog represented aroid species found in pristine forest
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