Time resolved emission spectroscopy of poly(2,5-dicyano-p-phenylene-vinylene) films

Films of poly (2,5-dicyano-p-phenylene vinylene), DCNPPV, were obtained by electrochemical synthesis over gold thin layer (20 nm) transparent electrode deposited on a glass plate. The DCNPPV films of 4 µm thickness were produced by electropolymerization process of α,α,α',α'-tetrabromo-2-5-dicyano-p-xilene at different applied potentials (-0.15, -0.25, -0.40, -0.60, -0.80, and -1.0 V) using 0.1 mol L-1 of tetraethylammonium bromide in acetonitrile as the supporting electrolyte. The emission decays have three exponential components: a fast component in the picosecond range (200-400 ps), and two other of about one and five nanoseconds at 293 K. The fluorescence quenching process seems to occur by exciton trapping in a low-energy site and quenching by residual bromine monomer attached at the end of the polymer chain. However, the electrochemical synthesis generates entrapped bromide or ion pairs during the growth step of the film which also contributes to the deactivation. The change of the electrolyte from bromide to perchlorate reduces significantly this additional quenching effect by allowing ion exchange of formed bromide with the nonquenching perchloride anion.Filmes finos de poli(2,5-diciano-p-fenileno vinileno), DCNPPV, foram produzidos por síntese eletroquímica com variação do potencial aplicado de-0,15 até-1,0 V, e depositados sobre camada fina de ouro sobre vidro. A cinética de estado excitado destes materiais foi investigada por medidas de decaimentos de fluorescência. Os filmes apresentam decaimentos com três componentes, uma rápida da ordem de 200-400 picossegundos, e outra duas componentes de aproximadamente um e cinco nanossegundos, na temperatura de 293 K. O decaimento de fluorescência ocorre pela desativação em sítios de baixa energia na cadeia polimérica conjugada e por supressão do estado excitado por monômeros bromados terminais da cadeia e íons brometo aprisionados durante o crescimento eletroquímico do filme. A mudança do ânion do eletrólito suporte de brometo para perclorato reduziu de modo significativo essa contribuição de supressão do estado excitado como resultado da troca iônica por uma espécie não supressora.FAPESPCNP

Mucocutaneous Response to New Therapeutic Strategies in Behçet’s Disease: A Retrospective Cohort Study

Mucocutaneous lesions are the most frequent symptoms of Behcet's disease (BD). Recently, new therapies are being used to treat refractory cases, but the effect of these treatments on mucocutaneous manifestations has been scarcely reported. Our objective was to describe the mucocutaneous response to the different therapies used to treat BD in routine clinical practice. We retrospectively reviewed the clinical records of all patients diagnosed with BD seen at our institution between January 2010 and January 2022. Patients with BD without mucocutaneous manifestations were excluded. We included 109 patients diagnosed with BD: 51 males (46.8%) and 58 females (53.2%). The mean age at diagnosis was 31.58 years (standard deviation (SD) 12.110) and the mean time of disease evolution was 14.94 years (SD 11.094). Oral ulcers were the most frequent symptom present in 100% of patients, followed by genital ulcers (GU) in 76.1% of patients. Twenty-four patients (22%) had severe mucocutaneous symptoms (> 12 lesions/year) before treatment. We found that among patients with GU there was a higher prevalence of episodes of posterior uveitis and venous thrombosis (p=0.011 and p=0.045, respectively). In our series, we observed a lower complete cutaneous response to colchicine in patients with GU, pathergy or severe mucocutaneous symptoms (p < 0.05). Regarding the choice of a TNF-alpha inhibitor, we observed a lower prevalence of complete cutaneous response to adalimumab among patients with GU (53.3% complete response in patients with GU vs. 100% in patients without GU, p=0.022), whereas no differences were found between clinical characteristics in the response to infliximab

Electroactive Nanostructured Membranes (ENM): Synthesis and Electrochemical Properties of Redox Mediator-Modified Gold Nanoparticles Using a Dendrimer Layer-by-Layer Approach

The layer-by-layer (LbL) self-assembly process has become an important tool in the fabrication of nanostructured devices for electrochemical applications, especially in those cases where control at the molecular level is required. In this paper we present a system based on electroactive nanostructured membranes (ENM) with ITO-PVS/PAMAM-Au LbL electrodes, in which a redox mediator (Me) is electrodeposited around the Au nanoparticles to form an ITO-PVS/PAMAM-Au@Me system. The redox mediators used were Co, Fe, Ni and Cu hexacyanoferrates. The 3-bilayer ITO-PVS/PAMAM-Au@Me system was characterized electrochemically by cyclic voltammetry and electrochemical impedance spectroscopy. All hexacyanoferrate modified electrodes showed electrocatalytic activity towards hydrogen peroxide, thus demonstrating that this new approach can be used in biosensors and nanodevices, where a redox mediator is required

The Use of Statins as an Adjunctive Periodontal Disease Treatment: Systematic Review and Meta-Analysis

Background: the purpose of this systematic review was to assess the clinical and radiographic effect of subgingival-administered statins as an adjunct periodontal treatment in patients with periodontitis. Methods: Electronic literature searches in Medline/PubMed and the Cochrane Library were conducted to identify all relevant articles. Eligibility was based on inclusion criteria which included Randomized Controlled Trials (RCTs) published after 2010, where the periodontal variables were assessed before and after periodontal treatment in combination with a statin administration. The risk of bias was assessed with the ROBINS-2 tool. The outcome variables were probing depth, clinical attachment level, bleeding on probing, and bone fill in systematically healthy patients, patients with type 2 diabetes, and smokers. Results: Out of 119 potentially eligible articles, 18 randomized controlled trials were included with a total of 1171 participants. The data retrieved from the meta-analysis showed the positive effect that statins have as an adjunctive periodontal disease treatment. When comparing the different types of statins, the PD reduction in the Simvastatin group was significantly higher than the Atorvastatin group at 6 months and at 9 months, while no differences between statins were found for the rest of the outcomes. Over 66% of the articles presented an overall risk of bias with some concerns, making this a limitation of this present RCT. Conclusions: The adjunct administration of statins has proven to have a positive effect on the periodontium by improving both clinical and radiographic parameters by a considerable margin

Evaluation of bone loss in antibacterial coated dental implants: An experimental study in dogs

The aim of this study was to evaluate the in vivo effect of antibacterial modified dental implants in the first stages of peri-implantitis. Thirty dental implants were inserted in the mandibular premolar sites of 5 beagle dogs. Sites were randomly assigned to Ti (untreated implants, 10 units), Ti_Ag (silver electrodeposition treatment, 10 units), and Ti_TSP (silanization treatment, 10 units). Coated implants were characterized by scanning electron microscopy, interferometry and X-ray photoelectron spectroscopy. Two months after implant insertion, experimental peri-implantitis was initiated by ligature placement. Ligatures were removed 2 months later, and plaque formation was allowed for 2 additional months. Clinical and radiographic analyses were p¬erformed during the study. Implant-tissue samples were prepared for micro computed tomography, backscattered scanning electron microscopy, histomorphometric and histological analyses and ion release measurements. X-ray, SEM and histology images showed that vertical bone resorption in treated implants was lower than in the control group (P < 0.05). This effect is likely due to the capacity of the treatments to reduce bacteria colonization on the implant surface. Histological analysis suggested an increase of peri-implant bone formation on silanized implants. However, the short post-ligature period was not enough to detect differences in clinical parameters among implant groups. Within the limits of this study, antibacterial surface treatments have a positive effect against bone resorption induced by peri-implantitis.Peer ReviewedPostprint (author's final draft

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Anàlisi de l'eficiència de la generació de neus de l'estació de Baqueira Beret

L’Anàlisi de l'eficiència de la generació de neu a la estació de BAQUEIRA BERET tracta sobre un anàlisi de components principals del consum dels canons de neu, on es busca la reducció de dades per tal de poder observar si podem obtenir alguna relació entre les variables que ens puguin fer veure una relació amb el consum. S’han identificat quines variables estan correlacionades amb el consum reduint la complexitat del problema i trobant que la correlació entre les diferents variables no permet deslligar-les per a deduir-ne conclusions directes que permetin reduir el consum.El análisis de la eficiencia de la generación de nieve en la estación de Baqueira Beret trata sobre un análisis de componentes principales del consumo de cañones de nieve, donde se busca la reducción de datos por tal de observar si podemos obtener alguna relación entre las variables que nos puedan hacer ver una relación con el consumo. Se han identificado que variables están correlacionadas con el consumo reduciendo la complejidad del problema y encontrando que la correlación entre las diferencias variables no permite desligarse para deducir conclusiones directas que permitan reducir el consumo.  The efficiency analysis of snow generation in the ski resort BAQUEIRA BERET is a principal component analysis about the consumption in snow guns, where we search data reduction in order to be able to find some relation between variables that can make us see a relation with the consumption. We have identified which variables are correlated with consumption by reducing the complexity of the problem and finding the correlation between the different variables does not allow us to untie them to find direct conclusions that reduce consumption

On the adsorption of sulfate on low Miller index Rh(hkl) electrodes: an in situ vibrational analysis

The adsorption of sulfate ion on Rh(111), Rh(100) and Rh(110) electrodes was studied using in situ FTIR reflection spectroscopy. For wavenumbers above 1200 cm-1, only one strong vibrational band is observed for adsorbed sulfate on the three low index rhodium surfaces. A weak band at 960 cm-1 is also observed for Rh(111). The strong band above 1200 cm-1 is potential dependent with a tuning rate of 50 cm-1 V-1. No differences were observed upon changing the solution acidity in order to provide sulfate or bisulfate in solution. This result is interpreted in terms of complete dissociation of the ions, giving only adsorbed SO4(2-). The surface orientation affects only the amount of the adsorbed sulfate species. It seems that the same adsorbed sulfate is present on Rh(111), Rh(110) and Rh(100)

In Situ Scanning Tunneling Microscopy Study of 5,6-Dimethyl Uracil on Au (111)

The hydrogen evolution mediated 5,6-dimethyluracil (5,6-DMU) film disordering and subsequent reordering was studied in situ in sulfuric acid solution on Au (111) using STM and cyclic voltammetry. A stable, condensed physisorbed film was formed between the limits of the hydrogen evolution (at -0.3 V/SCE) and the lifting of the surface reconstruction (at 0.4 V/SCE) in the bulk solution concentration used in this study. The onset of hydrogen evolution led to the formation of "bubble" like structures which disrupted the stability of the film causing a disordering process which takes place within the whole scanned area. Stepping the potential back to the region of stability allowed the real time observation of the film reorganization. An anisotropic evolution of the film was found. The surface step edges were not found to be preferential nucleation sites. The molecular packing structure was inferred from high-resolution STM images and the existence of two distinct adsorbate states was established