Corantes azo para impressão a jacto de tinta com boa solidez à água

Dissertação de Mestrado em Química - Área de Especialização em EnsinoO uso de impressoras a jacto de tinta e a elaboração de tintas especiais para a impressão em papel ou outras superfícies tem sido objecto de uma exaustiva investigação ao longo dos últimos anos. Corantes solúveis em água têm fornecido os componentes coloridos utilizados em algumas tintas, embora os pigmentos tenham encontrado também um grande crescimento. Contudo, do uso de pigmentos advêm muitos problemas, a maioria relacionada com a dispersão, instabilidade e no entupimento das cabeças de impressão. Assim sendo, há vantagens consideráveis no desenvolvimento de tintas solúveis em água que tenham uma secagem mais rápida no papel. Muitas tintas solúveis em água são feitas a partir de corantes cuja solubilidade na água é devida à presença de grupos do tipo ácido sulfónico. Contudo, o grupo sulfónico contribui para a solubilidade mas não para a solidez à água. Por esta razão, nos últimos anos têm surgido tintas baseadas em corantes solúveis em solventes orgânicos. O objectivo deste trabalho foi sintetizar corantes para impressão a jacto de tinta solúveis em água e com boa solidez à água, quando absorvidos pelo papel. Inicialmente procedeu-se à síntese dos corantes azo, envolvendo a redução do anidrido-3-nitro-1,8-naftálico e posterior diazotação do resultante anidrido-3-amino-1,8-naftálico. O método de diazotação foi determinado por testes cinéticos, efectuados por HPLC, seguindo-se o acoplamento do sal de diazónio com os vários componentes de acoplamento: N,N-dimetilanilina, 3-(N,N-dietilamino)-acetanilida, 3-metil-1-fenil-5-pirazolona, 2,6-dihidróxi-4-metil-3-ciano piridina e 2,2-dimetil-1,3-dihidro-4,5-naftil-1H-perimidina. Após a purificação e a caracterização espectroscópica dos corantes, efectuaram-se testes de solidez à água em papel (testes simples, ao nível laboratorial) e consequente avaliação.The use of ink jet printers and the formulation of special inks for printing on paper and other substrates has been the subject of intensive investigation for several years. Water soluble dyes (rather than pigments) have usually provided the colouring components in such inks, although pigments are finding increasing favour. However, the use of pigments has many problems, most notably those of dispersion stability and jet clogging. Thus there is considerable advantages in developing water soluble dyes which, in the dry state, have high wet fastness on paper. Most inks are based on dyes whose water solubility is provided by sulphonic acid groups. However, the sulphonate group contributes to solubility but not to water fastness. For this reason, non-aqueous ink jet inks based on organic solvent soluble dyes have also received attention in recent years. The purpose of this work is to synthesize water soluble ink jet dyes which have good water resistance when adsorbed on paper. The synthesis of azo dyes started with the reduction of the 3-nitro-1,8-naphthalic anhydride, followed by diazotization of the resulting 3-amino-1,8-naphthalic anhydride. The diazotization method was determined by kinetics tests, through HPLC monitoring. The coupling with various coupling components such as N,N-dimethylanilin, 3-(N,N-diethylamino)acetanilide, 3-methyl-1-phenyl-2-pyrazolin-5-one, 2,6-dihydroxy-4-methyl-3-pyridinecarbonitrile and 2,2-dimethyl-1,3-dihydro-4,5-naphthyl-1H-perimidine, afforded the azo dyes required in colours from yellow to red and black. After the purification and complete spectroscopic characterization of the dyes, water fastness tests on paper (simple tests, on the laboratorial level) and consequent evaluation were carried out

Bioinspired cyclic dipeptide functionalized nanofibers for thermal sensing and energy harvesting

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ma16062477/s1, Figure S1: Optical microscopy; Figure S2: Output voltage as a function of time from Cyclo (L-Trp-L-Trp)@PLLA electrospun nanofibers; Figure S3: Piezoelectric current versus applied force for Cyclo (L-Trp-L-Trp)@PLLA and PLLA neat fibers, with the respective linear fits; Figure S4: Output voltage for low frequencies up to 10 Hz and output voltage as a function of time, from Cyclo (L-Trp-L-Trp)@PCL electrospun nanofibers.Nanostructured dipeptide self-assemblies exhibiting quantum confinement are of great interest due to their potential applications in the field of materials science as optoelectronic materials for energy harvesting devices. Cyclic dipeptides are an emerging outstanding group of ring-shaped dipeptides, which, because of multiple interactions, self-assemble in supramolecular structures with different morphologies showing quantum confinement and photoluminescence. Chiral cyclic dipeptides may also display piezoelectricity and pyroelectricity properties with potential applications in new sources of nano energy. Among those, aromatic cyclo-dipeptides containing the amino acid tryptophan are wide-band gap semiconductors displaying the high mechanical rigidity, photoluminescence and piezoelectric properties to be used in power generation. In this work, we report the fabrication of hybrid systems based on chiral cyclo-dipeptide L-Tryptophan-L-Tryptophan incorporated into biopolymer electrospun fibers. The micro/nanofibers contain self-assembled nano-spheres embedded into the polymer matrix, are wide-band gap semiconductors with 4.0 eV band gap energy, and display blue photoluminescence as well as relevant piezoelectric and pyroelectric properties with coefficients as high as 57 CN−1 and  35×10−6 Cm−2K−1, respectively. Therefore, the fabricated hybrid mats are promising systems for future thermal sensing and energy harvesting applications.This research was funded by Fundação para a Ciência e Tecnologia through FEDER (European Fund for Regional Development)-COMPETE-QREN-EU (ref. UID/FIS/04650/2013 and UID/FIS/04650/2019) and E-Field“Electric-Field Engineered Lattice Distortions (E-FiELD) for optoelectronic devices, ref. PTDC/NAN-MAT/0098/2020

High Piezoelectric Output Voltage from Blue Fluorescent N,N-Dimethyl-4-nitroaniline Nano Crystals in Poly-L-Lactic Acid Electrospun Fibers

N,N-dimethyl-4-nitroaniline is a piezoelectric organic superplastic and superelastic charge transfer molecular crystal that crystallizes in an acentric structure. Organic mechanical flexible crystals are of great importance as they stand between soft matter and inorganic crystals. Highly aligned poly-l-lactic acid polymer microfibers with embedded N,N-dimethyl-4-nitroaniline nanocrystals are fabricated using the electrospinning technique, and their piezoelectric and optical properties are explored as hybrid systems. The composite fibers display an extraordinarily high piezoelectric output response, where for a small stress of 5.0 × 103 Nm−2, an effective piezoelectric voltage coefficient of geff = 4.1 VmN−1 is obtained, which is one of the highest among piezoelectric polymers and organic lead perovskites. Mechanically, they exhibit an average increase of 67% in the Young modulus compared to polymer microfibers alone, reaching 55 MPa, while the tensile strength reaches 2.8 MPa. Furthermore, the fibers show solid-state blue fluorescence, important for emission applications, with a long lifetime decay (147 ns) lifetime decay. The present results show that nanocrystals from small organic molecules with luminescent, elastic and piezoelectric properties form a mechanically strong hybrid functional 2-dimensional array, promising for applications in energy harvesting through the piezoelectric effect and as solid-state blue emitters.This research was funded by Fundação para a Ciência e Tecnologia through FEDER (European Fund for Regional Development)-COMPETE-QREN-EU (ref. UID/FIS/04650/2013 and UID/FIS/04650/2019) and E-Field - "Electric-Field Engineered Lattice Distortions (E-FiELD) for optoelectronic devices", ref. PTDC/NAN-MAT/0098/2020

Functionalized magnetic composite nano/ microfibres with highly oriented van der Waals CrI3 inclusions by electrospinning

This study reports on the synthesis of highly oriented chromium triiodide (CrI3) magnetic inclusions inside nano/microfibres with a polyethylene oxide matrix, prepared by the electrospinning technique. The structural, microstructural and spectroscopic analysis shows uniformly dispersed CrI3 nanosized inclusions inside the fibres, presenting a C2/m monoclinic structure at room temperature, where their c-axis is perpendicular to the fibre mat plane and the ab layers are in-plane. Analysis of the magnetic properties show that the samples have a ferromagnetic-paramagnetic phase transition at ∼55-56 K, lower than that of bulk CrI3. Noticeably, a field-driven metamagnetic transition is observed below ∼45 K, from M versus H curves, when the applied magnetic field is perpendicular to the fibre mat plane, while it is strongly reduced when the field is in-plane. This anisotropic behaviour is attributed to the field-induced changes from antiferromagnetic to ferromagnetic interlayer magnetic moment alignment along the CrI3 c-axis stacked layers. These CrI3 electrospun fibres then show an efficient cost-effective route to synthesize magnetic composite fibres with highly oriented van der Walls inclusions, for spintronic applications, taking advantage of their anisotropic 2D layered materials properties.We are grateful to the Fundacao Para a Ciencia e a Tecnologia (FCT) for the financial support through the Physics Centers of the Universities of Minho and Porto (Ref. UIDB/04650/2020) and projects UTAPEXPL/NTec/0046/2017, NORTE-01-0145-FEDER-028538 and PTDC/FIS-MAC/29454/2017. J H Belo thanks FCT for the Grant SFRH/BD/88440/2012, the project PTDC/FIS-MAC/31302/2017 and his contract DL57/2016 reference SFRH-BPD-87430/2012. J P Araujo and J H Belo thank the funding from the project, with reference POCI-01-0145-FEDER-032527. V B Isfahani acknowledges a Post-Doc grant from the project NORTE-01-0145-FEDER-028538. L Boddapati acknowledges the Nano TRAIN for Growth II program by the European Commission through the Horizon 2020 Marie Sklodowska-Curie COFUND Programme and support provided by the International Iberian Nanotechnology Laboratory. We are gratefull to Professor Michael Belsley, of the Physics Department at Minho University, for the fruitfull discussions on the manuscript

Motivos de exclusão para a cirurgia de estimulação cerebral profunda na doença de Parkinson

Abstract de comunicação apresentada no Congresso SPDMov 2022 - Parkinsonismos Atípicos: Clássicos e Atípicos. Luso, 1-2 Abril 2022N/

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages