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In this work, highly conductive and transparent films based on poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) doped with dimethyl sulfoxide (DMSO) were printed onto a flexible substrate, the polyethylene naphthalate (PEN), using the gravure printing method. Gravure-printed DMSO-PEDOT:PSS ink suitably modified with isopropanol was developed and used as anode in flexible solar cells replacing the commonly used anode, that is, Indium Tin Oxide (ITO). Several inks were prepared and characterized in terms of viscosity and surface energy and tested by gravure printing. The wettability of the PEN substrate was investigated through contact angle measurements. For comparison, the anodic conductive polymer was also spin coated on the PEN substrate using an ink suitable for this technique. The films produced with both the techniques, gravure printing and spin coating, each using a proper ink, were characterized in terms of structure and physical-chemical properties. The printed layers were employed as anodes into ITO free-polymer solar cells based on a bulk heterojunction of Poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2- b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno [3,4- b]thiophenediyl}) (PTB7) and [6,6]-phenyl C70-butyric acid methyl ester ([70]PCBM). The performances of the devices with printed and spin coated polymeric anode were compared. The cell with the spin-coated anode reached a power conversion efficiency of 3% while the corresponding device with the printed anode a value around 2%. POLYM. COMPOS., 36:1104-1109, 2015. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

We develop a nonlinear asymptotic theory of flow and bed topography in meandering channels able to describe finite amplitude perturbations of bottom topography and account for arbitrary, yet slow, variations of channel curvature. This approach then allows us to formulate a nonlinear bend instability theory, which predicts several characteristic features of the actual meandering process and extends results obtained by classical linear bend theories. In particular, in agreement with previous weakly nonlinear findings and consistently with field observations, the bend growth rate is found to peak at some value of the meander wave number, reminiscent of the resonant value of linear stability theory. Moreover, a feature typical of nonlinear waves arises: the selected wave number depends on the amplitude of the initial perturbation (for given values of the relevant dimensionless parameters), and in particular, larger wavelengths are associated with larger amplitudes. Meanders are found to migrate preferentially downstream, though upstream migration is found to be possible for relatively large values of the aspect ratio of the channel, a finding in agreement with the picture provided by linear theory. Meanders are found to slow down as their amplitude increases, again a feature typical of nonlinear waves, driven in the present case by flow rather than geometric nonlinearities. The model is substantiated by comparing predictions with field observations obtained for a test case. The potential use of the present approach to investigate a number of as yet unexplored aspects of meander evolution (e.g., chute cutoff) is finally discussed. [ABSTRACT FROM AUTHOR]

A rapid and sensitive real time reverse transcription-PCR (RT-PCR) assay based on SYBR Green I chemistry was developed for the quantitative detection of Citrus viroid III (CVd-III) in citrus samples. CVd-III titre was determined at different times in green bark of sour orange, Troyer citrange, trifoliate orange and alemow seedlings inoculated with a CVd-IIIb source. Ten weeks after inoculation the viroid was detected in the four species, without substantial differences in viroid titre among them. Nine weeks later an overall increase of viroid titre was observed. The copy number of CVd-III in sour orange and Troyer citrange was monitored up to 52 weeks after inoculation and a further increase of viroid titre was observed at 35 weeks. For validation purposes, field samples were tested from 58 citrus trees with mixed infections of CVd-III, Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd), as well as from healthy controls. Based on the sensitivity (100%), specificity (96·7%), accuracy (99·2%) and repeatability (Cohen's kappa index 0·98) of the assay, it is suggested that its employment in breeding programmes would be helpful in the evaluation of host resistance and viroid accumulation in plants. [ABSTRACT FROM AUTHOR]