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Bioassays against pinewood nematode: assessment of a suitable dilution agent an...
Barbosa, P.; Faria, J.M.S.; Mendes, M.D.; Dias, L.S.; Tinoco, M.T.; Barroso, J.G.; Pedro, L.G.; Figueiredo, A.C.; Mota, M.Acetone was investigated and found to be an appropriate alternative to Triton X-100 as a solvent of essential oils in bioassays aimed to investigate their effects on pinewood nematode (Bursaphelenchus xylophilus) mortality. Therefore it was used as dilution agent to screen the effectiveness of fifty two essential oils against this pest. Thirteen essential oils were highly effective, resulting in more than 90% p...
Characterization of polyether-poly(methyl methacrylate)-lithium perchlorate ble...
Barbosa, P. C.; Rodrigues, L. C.; Silva, Maria Manuela; Smith, Michael John; Valente, Prudência B.; Gonçalves, A.; Fortunato, E.Em publicação ; Solid polymer electrolytes (SPEs) systems based on interpenetrating blends of poly(ethylene oxide-co-propylene oxide) and poly(methyl methacrylate) host matrices, with lithium perchlorate as guest salt, were prepared. These electrolytes were presented as free-standing films, and their thermal and electrochemical properties were characterized by conductivity and electrochemical stability measure...
Characterization of pTMCnLiPF6 solid polymer electrolytes
Barbosa, P. C.; Rodrigues, L. C.; Silva, Maria Manuela; Smith, Michael JohnIn this study the results our characterization of a solid polymer electrolyte based on poly(trimethylene carbonate), henceforth designated as p(TMC), and lithium hexafluorophosphate (LiPF6) are described. Samples of solvent-free electrolytes were prepared with a range of concentration of guest salt using solvent casting from tetrahydrofuran and characterized by conductivity measurements, thermal analysis and el...
Di-ureasil hybrids doped with LiBF4 : attractive candidates as electrolytes for...
Barbosa, P. C.; Fernandes, M.; Silva, Maria Manuela; Smith, Michael John; Vilela, Sérgio M. F.; Gonçalves, A.; Olveira, M. C.; Fortunato, E.; Rego, R.The sol-gel process has been used to prepare hybrid electrolytes composed of a poly(oxyethylene) (POE)/siloxane hybrid network doped with lithium tetrafluoroborate (LiBF4) with compositions of n between ∞ and 2.5. In this context the lithium salt concentration is expressed in terms of the number of oxyethylene units in the organic component of the network per Li+ ion. Electrolyte samples with n ≥ 20 are thermal...
Di-ureasil hybrids doped with LiBF4 : spectroscopic study of the ionic interact...
Fernandes, Mariana; Barbosa, P. C.; Silva, Maria Manuela; Smith, Michael John; Zea Bermudez, V. deIn the present work Fourier Transform infrared and Raman spectroscopy were used to characterize the cation/polymer, cation/cross-link, cation/anion and hydrogen bonding interactions in hybrid electrolytes composed of lithium tetrafluoroborate (LiBF4) and di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks (di-ureasils) designated as d-(2000) and d-U(600) and incorporating polyether chains with...
Nematicidal activity of essential oils and volatiles derived from Portuguese ar...
Barbosa, P.; Lima, A.S.; Vieira, P.; Dias, L.S.; Tinoco, M.T.; Barroso, J.G.; Pedro, L.G.; Figueiredo, A.C.; Mota, M.Twenty seven essential oils, isolated from plants representing 11 families of Portuguese flora, were screened for their nematicidal activity against the pinewood nematode (PWN), Bursaphelenchus xylophilus. The essential oils were isolated by hydrodistillation and the volatiles by distillation-extraction, and both were analysed by GC and GC-MS. High nematicidal activity was achieved with essential oils from Cham...
Solid-state electrochromic devices using pTMC/PEO blends as polymer electrolytes
Barbosa, P. C.; Rodrigues, L. C.; Silva, Maria Manuela; Smith, Michael John; Parola, A. J.; Pina, F.; Pinheiro, CarlosFlexible, transparent and self-supporting electrolyte films based on poly(trimethylene carbonate)/poly(ethylene oxide) ((p(TMC)/PEO) interpenetrating networks doped with LiClO4 were prepared by the solvent casting technique. These novel solid polymer electrolyte (SPE) systems were characterized by measurements of conductivity, cyclic voltammetry, differential scanning calorimetry and thermogravimetry. The incor...
Mg2+-doped poly(ε-caprolactone)/siloxane biohybrids
Teixeira, J. C. S.; Fernandes, M.; Zea Bermudez, V. de; Barbosa, P. C.; Rodrigues, L. C.; Silva, Maria Manuela; Smith, Michael JohnElectrolytes based on a poly(ε-caprolactone) (PCL)/siloxane organic/inorganic host framework doped with magnesium triflate (Mg(CF3SO3)2) were synthesized by the sol-gel process. In the biohybrid matrix short PCL chains are covalently bonded via urethane linkages to the siliceous network. In this study the salt content of samples was identified using the conventional n notation, where n indicates the number of (...
Synthesis and thermal behaviour of an amorphous solid polymer electrolyte
Barbosa, P. C.; Rodrigues, L. C.; Silva, Maria Manuela; Smith, Michael John; Costa, Marta Sílvia Freitas daIn this study the synthesis of an amorphous polymer network, poly[oxymethylene-oligo(oxyethylene)], designated as aPEO, is described. This polymer has been characterized by gel permeation chromatography, thermal analysis, conductivity measurements, evaluation of electrochemical stability and nuclear magnetic resonance spectroscopy. The synthetic procedure developed permits partial fractionation of the product o...
Circadian cardiac autonomic function in perinatally HIV-infected preschool chil...
Benchimol-Barbosa,P.R.The 24-h heart rate variability and QT-interval adaptation was investigated in perinatally HIV-infected preschool children classified according to immunological status in order to assess autonomic function at early stages of infection. Thirty-five perinatally HIV-infected and clinically stable children (4.8 ± 0.3 years) were enrolled after approval of the study by the University Hospital Pedro Ernesto Ethics Co...
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