482 research outputs found
Substrate integrated waveguide (SIW) bandpass filter with novel microstrip-CPW-SIW input coupling
A Substrate integrated waveguide bandpass filter is presented with a novel CPW-to-SIW transition at both the input and output ports which also served as the input and output couplings into the filter. The CPW-to-SIW transition structures presented here exploited the step impedance between the 50 ohms input/output feedline and the transition to control the input/output couplings of the filter. The SIW filter is also shown to have very minimum milling or etching requirement which reduces the fabrication error. The proposed SIW filter has been validated experimentally and results presented. The results show that a simulated return loss of 15 dB and an initial measured return loss of 16 dB were achieved. An improved measured return loss of 22 dB was later achieved after some tuining adjustments were performed on the filter input and output couplings. A minimum insertion loss of 1.3 dB was also achieved across the band
Thru-reflect-line calibration for substrate integrated waveguide devices with tapered microstrip transitions
One of the main problems when exciting or measuring substrate integrated waveguide (SIW) devices lies in the need of a good interconnection with planar structures. In this reported work, the negative effects produced by the connectors and the tapered microstrip-to-SIW transitions are de-embedded from the measurements of the SIW structure by a thru-reflect-line calibration with an adequate and cheap SIW calibration kit.DΓaz Caballero, E.; Belenguer MartΓnez, Γ.; Esteban GonzΓ‘lez, H.; Boria Esbert, VE. (2013). Thru-reflect-line calibration for substrate integrated waveguide devices with tapered microstrip transitions. Electronics Letters. 49(2):132-133. doi:10.1049/el.2012.3027S132133492Deslandes, D., & Wu, K. (2001). Integrated microstrip and rectangular waveguide in planar form. IEEE Microwave and Wireless Components Letters, 11(2), 68-70. doi:10.1109/7260.914305Henry, M., Free, C. E., Izqueirdo, B. S., Batchelor, J., & Young, P. (2009). Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis. IEEE Transactions on Advanced Packaging, 32(1), 93-100. doi:10.1109/tadvp.2008.2011284Chen, X.-P., Wu, K., & Li, Z.-L. (2007). Dual-Band and Triple-Band Substrate Integrated Waveguide Filters With Chebyshev and Quasi-Elliptic Responses. IEEE Transactions on Microwave Theory and Techniques, 55(12), 2569-2578. doi:10.1109/tmtt.2007.909603Deslandes, D., & Ke Wu. (2005). Analysis and design of current probe transition from grounded coplanar to substrate integrated rectangular waveguides. IEEE Transactions on Microwave Theory and Techniques, 53(8), 2487-2494. doi:10.1109/tmtt.2005.852778Engen, G. F., & Hoer, C. A. (1979). Thru-Reflect-Line: An Improved Technique for Calibrating the Dual Six-Port Automatic Network Analyzer. IEEE Transactions on Microwave Theory and Techniques, 27(12), 987-993. doi:10.1109/tmtt.1979.1129778Chih-Jung Chen, & Tah-Hsiung Chu. (2009). Measurement of Noncoaxial Multiport Devices Up to the Intrinsic Ports. IEEE Transactions on Microwave Theory and Techniques, 57(5), 1230-1236. doi:10.1109/tmtt.2009.201735
A Repeated Measures Experiment of Green Exercise to Improve Self-Esteem in UK School Children
Exercising in natural, green environments creates greater improvements in adult's self-esteem than exercise undertaken in urban or indoor settings. No comparable data are available for children. The aim of this study was to determine whether so called 'green exercise' affected changes in self-esteem; enjoyment and perceived exertion in children differently to urban exercise. We assessed cardiorespiratory fitness (20 m shuttle-run) and self-reported physical activity (PAQ-A) in 11 and 12 year olds (n = 75). Each pupil completed two 1.5 mile timed runs, one in an urban and another in a rural environment. Trials were completed one week apart during scheduled physical education lessons allocated using a repeated measures design. Self-esteem was measured before and after each trial, ratings of perceived exertion (RPE) and enjoyment were assessed after completing each trial. We found a significant main effect (F (1,74), = 12.2, p<0.001), for the increase in self-esteem following exercise but there was no condition by exercise interaction (F (1,74), = 0.13, p = 0.72). There were no significant differences in perceived exertion or enjoyment between conditions. There was a negative correlation (r = -0.26, p = 0.04) between habitual physical activity and RPE during the control condition, which was not evident in the green exercise condition (r = -0.07, p = 0.55). Contrary to previous studies in adults, green exercise did not produce significantly greater increases in self-esteem than the urban exercise condition. Green exercise was enjoyed more equally by children with differing levels of habitual physical activity and has the potential to engage less active children in exercise. Β© 2013 Reed et al
An initial event in insect innate immune response: structural and biological studies of interactions between Ξ²-1,3-glucan and the N-terminal domain of Ξ²-1,3-glucan recognition protein
In response to invading microorganisms, insect Ξ²-1,3-glucan recognition protein (Ξ²GRP), a soluble receptor in the hemolymph, binds to the surfaces of bacteria and fungi and activates serine protease cascades that promote destruction of pathogens by means of melanization or expression of antimicrobial peptides. Here we report on the NMR solution structure of the N-terminal domain of Ξ²GRP (N-Ξ²GRP) from Indian meal moth (Plodia interpunctella), which is sufficient to activate the prophenoloxidase (proPO) pathway resulting in melanin formation. NMR and isothermal calorimetric titrations of N-Ξ²GRP with laminarihexaose, a glucose hexamer containing Ξ²-1,3 links, suggest a weak binding of the ligand. However, addition of laminarin, a glucose polysaccharide (~ 6 kDa) containing Ξ²-1,3 and Ξ²-1,6 links that activates the proPO pathway, to N-Ξ²GRP results in the loss of NMR cross-peaks from the backbone 15N-1H groups of the protein, suggesting the formation of a large complex. Analytical ultra centrifugation (AUC) studies of formation of N-Ξ²GRP:laminarin complex show that ligand-binding induces sel-fassociation of the protein:carbohydrate complex into a macro structure, likely containing six protein and three laminarin molecules (~ 102 kDa). The macro complex is quite stable, as it does not undergo dissociation upon dilution to sub-micromolar concentrations. The structural model thus derived from the present studies for N-Ξ²GRP:laminarin complex in solution differs from the one in which a single N-Ξ²GRP molecule has been proposed to bind to a triple helical form of laminarin on the basis of an X-ray crystallographic structure of N-Ξ²GRP:laminarihexaose complex [Kanagawa, M., Satoh, T., Ikeda, A., Adachi, Y., Ohno, N., and Yamaguchi, Y. (2011) J. Biol. Chem. 286, 29158-29165]. AUC studies and phenoloxidase activation measurements carried out with the designed mutants of N-Ξ²GRP indicate that electrostatic interactions involving Asp45, Arg54, and Asp68 between the ligand-bound protein molecules contribute in part to the stability of N-Ξ²GRP:laminarin macro complex and that a decreased stability is accompanied by a reduced activation of the proPO pathway. Increased Ξ²-1,6 branching in laminarin also results in destabilization of the macro complex. These novel findings suggest that ligand-induced self-association of Ξ²GRP:Ξ²-1,3-glucan complex may form a platform on a microbial surface for recruitment of downstream proteases, as a means of amplification of the initial signal of pathogen recognition for the activation of the proPO pathway
Avaliação das açáes de aconselhamento. AnÑlise de uma perspectiva de prevenção centrada na pessoa
Transcriptional Responses of Arabidopsis thaliana during Wilt Disease Caused by the Soil-Borne Phytopathogenic Bacterium, Ralstonia solanacearum
Bacterial wilt is a common disease that causes severe yield and quality losses in many plants. In the present study, we used the model Ralstonia solanacearum-Arabidopsis thaliana pathosystem to study transcriptional changes associated with wilt disease development. Susceptible Col-5 plants and RRS1-R-containing resistant Nd-1 plants were root-inoculated with R. solanacearum strains harbouring or lacking the matching PopP2 avirulence gene. Gene expression was marginally affected in leaves during the early stages of infection. Major changes in transcript levels took place between 4 and 5 days after pathogen inoculation, at the onset of appearance of wilt symptoms. Up-regulated genes in diseased plants included ABA-, senescence- and basal resistance-associated genes. The influence of the plant genetic background on disease-associated gene expression is weak although some genes appeared to be specifically up-regulated in Nd-1 plants. Inactivation of some disease-associated genes led to alterations in the plant responses to a virulent strain of the pathogen. In contrast to other pathosystems, very little overlap in gene expression was detected between the early phases of the resistance response and the late stages of disease development. This observation may be explained by the fact that above-ground tissues were sampled for profiling whereas the bacteria were applied to root tissues
An RxLR effector from phytophthora infestans prevents re-localisation of two plant NAC transcription factors from the endoplasmic reticulum to the nucleus
The plant immune system is activated following the perception of exposed, essential and invariant microbial molecules that are recognised as non-self. A major component of plant immunity is the transcriptional induction of genes involved in a wide array of defence responses. In turn, adapted pathogens deliver effector proteins that act either inside or outside plant cells to manipulate host processes, often through their direct action on plant protein targets. To date, few effectors have been shown to directly manipulate transcriptional regulators of plant defence. Moreover, little is known generally about the modes of action of effectors from filamentous (fungal and oomycete) plant pathogens. We describe an effector, called Pi03192, from the late blight pathogen Phytophthora infestans, which interacts with a pair of host transcription factors at the endoplasmic reticulum (ER) inside plant cells. We show that these transcription factors are released from the ER to enter the nucleus, following pathogen perception, and are important in restricting disease. Pi03192 prevents the plant transcription factors from accumulating in the host nucleus, revealing a novel means of enhancing host susceptibility
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Development of consensus based national antimicrobial stewardship competencies for UK undergraduate healthcare professional education
Background: Healthcare professionals are involved in an array of patient and medicine related stewardship activities, for which an understanding and engagement with antimicrobial stewardship is important. Undergraduate education provides an ideal opportunity to prepare healthcare professionals for these roles and activities.
Aim: To provide United Kingdom national consensus on a common set of antimicrobial stewardship competencies appropriate for undergraduate healthcare professional education
Methods: A modified Delphi approach comprising two on-line surveys delivered to a United Kingdom national panel of twenty-one individuals reflecting expertise in prescribing and medicines management with regards to the education and practice of nurses and midwives, pharmacists, physiotherapists and podiatrists; and antimicrobial prescribing and stewardship. Data collection took place between October and December 2017.
Findings: A total of 21 participants agreed to become members of the expert panel, of whom 19 (90%) completed round 1 questionnaire, and 17 (89%) completed round 2. Panelists reached a consensus, with consistent high levels of agreement reached, on 6 overarching competency statements (sub divided into 6 domains), and 55 individual descriptors essential for antimicrobial stewardship by healthcare professionals
Authentic leading as relational accountability: Facing up to the conflicting expectations of media leaders
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