Hueder Paulo Moisés De Oliveira

Universidade Federal do ABC (UFABC) | UFABC · Department of Chemistry

The aim of this study was to evaluate the effect of SPP with either fetal bovine serum (FBS) or deionized water (DW) on the bond strength (μTBS) of a Universal adhesive to dentin, in both etch-and-rinse (ER) and self-etch (SE) modes. The kinematic viscosity (cSt) of FBS and DW was measured at 25 °C ± 0.1 ºC. Seventy-two sound human molars were sect...

Glycolic acid and lactic acid substituted zinc phthalocyanines were studied concerning their photophysical and photochemical properties in eight organic solvents (homogeneous medium) and in aqueous media with the presence of CTAB and PVP 360 surfactants. Solvent effects were investigated according to several physical solvent parameters, including s...

The tetra-methyl and tetra-tert-butyl phthalocyanines were synthesized by cyclotetramerization of phthalonitriles and phthalic anhydride derivatives by traditional and microwave synthesis. Spectroscopic data were obtained for the Zinc(II) and Aluminum(III) derivatives, and solvent effects were investigated in dimethyl sulfoxide (DMSO), N,N-dimethyl...

Silver nanoparticles (AgNPs) are incredibly versatile nanostructures that more recently have been exploited to create advanced optoelectronic materials due enhancement of local magnetic field after its irradiation. However, the use of AgNPs as nanoantennas to amplify photophysical properties of close photosensitizer (PS) molecules in photodynamic t...

Trata-se de um estudo estatístico sobre as diferentes moedas de cinquenta centavos e um real em circulação no Brasil, elaborado a partir da mudança de padrões ocorrida na fabricação destas moedas no início do século XXI. Publicado na Revista Brasileira de Numismática XXIV, n.1, 2020.

In this study we report a novel theranostic lipid-polymer liposome, obtained from DPPC and the triblock copolymer F127 covalently modified with 5(6)-carboxyfluorescein (CF) for photodynamic applications. Due to the presence of F127, small unilamellar vesicle (SUV) liposomes were synthesized by a simple and fast thin-film hydration method without th...

The combination of conjugated polymers and photochromic molecules can result in a composite, which can yield a new photoresponsive material. The efficiency of these materials is due to the process of energy transfer. In this work, the conjugated polymer poly (3-hexylthiophene-co-1,4-phenylene) (PTPh) was synthesized by Suzuki route and the photochr...

Nanotechnology development provides new strategies to improve different treatment modalities by integration of multiple molecules in a single multifunctional nanoparticle. In this scenario, we highlight silver nanoparticles (AgNPs) favorable optical properties such as absorption and emission of light in the visible region of the spectrum. This allo...

Phenothiazines are a class of molecules that have been applied in antipsychotic therapy, photodynamic therapy, dyes, sunscreen, and more recently light-harvesting for energy applications. In the present study, the photochemical properties of phenothiazine aggregates were used for oxidative catalysis and synthesis of gold nanoparticles with potentia...

Sensors efficiency relies directly on the involved materials and, in many cases, the combination of two different conjugated polymers can lead to better sensors; due to the increase observed at the photophysics process of energy transfer. In this work, the polymers poly[(9,9-dioctylfluorene)-co-biphenylene] (PFB), poly[(9,9-dioctylfluorene)-co-phen...

The objectives of this study were to determine the viability of removing Orange II (OII) dye by simulated solar photoelectro-Fenton (SSPEF) and to evaluate the stability of a WO2.72/Vulcan XC72 gas diffusion electrode (GDE) and thus determine its best operating parameters. The GDE cathode was combined with a BDD anode for decolorization and mineral...

A simple, fast, and direct electroanalytical method has been developed for the pesticide chlorothalonil determination using a boron-doped diamond electrode and square-wave voltammetry technique. In the pH range values between 8.0 and 10.0, the voltammetric results showed three reduction peaks − 1.07, − 1.2, and − 1.4 V (vs. Ag/AgCl) for the chlorot...

Several anti-proteolytic dentin therapies are being exhaustively studied in an attempt to reduce dentin bond degradation and improve clinical performance and longevity of adhesive restorations. Objectives This study assessed the effect of epigallocatechin-3-gallate (EGCG) on long-term bond strength when incorporated into adhesives. Material and M...

Copper porphyrin was immobilized inside of MCM-41 pores using two different methods, by direct addition of copper porphyrin into the MCM-41 pores and by using aminopropyl group as coupling and spacing group. In the second method the aminopropyl group was previously bonded to copper porphyrin ring, resulting in material with higher copper porphyrin...

The present work is focused on spectroscopic evaluations, employing optical absorption and fluorescence emission spectroscopies of chlorophylls and chlorophilic derivatives as well as the complex chemical systems originated by the interaction between chlorophyll compounds and agrochemicals, such as pesticides and insecticides. Considering the great...

There are many scientific discoveries and technology developments that are currently taken for granted in society as a whole, as if these had always existed. In an educational context this means that students have lost the ability to see themselves as delevopers of new technologies, assuming a role as mere users of the technologies made available b...

4,5-Dicyanopyridazine (DCP) shows unexpected reactivity with dienophiles via Hetero Diels-Alder. Reactions involving this compound and alkynes or enamines was already described, open possibilities to synthesize precursors for important macromolecules, like phthalonitriles used in phthalocyanines synthesis. Herein, we present a microwave synthetic s...

Photophysical and photochemical properties of lithium phthalocyanine (1), gallium(III) phthalocyanine chloride (2), titanium(IV) phthalocyanine dichloride (3) and iron(II) phthalocyanine (4) were investigated in dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and DMSO-THF mixtures. The influence of the central metal on these properties was analyze...

In this work is presented a spectrophotometric investigation focused on the solvatochromic effects upon Methylene Blue (MB). Measurements were carried out in four different water/organic solvent mixtures: low polarity protic solvent (ethanol), polar non-protic solvent (acetonitrile), highly polar protic solvent (glycerol), and non-polar solvent (di...

In this work, excitation and emission spectra were evaluated in order to elucidate the properties of quinguangulin and rubrofusarin in water/ethanol mixture. The study demonstrates that the maximum excitation wavelength can be significantly modulated changing the proportion of organic solvent in the water/organic solvent system. Quinquangulin prese...

In the present study we estimated the Critical Micelle Concentration (CMC) of Triton X-100 in an aqueous buffered medium (PBS buffer, pH 7.4), using 3-(benzoxazol-2-yl)-7-(N,N-diethylamino)chromen-2-one (BDC), a push-pull compound, as extrinsic fluorescence probe. The CMC value found, 0.33 mmol L-1, shows good agreement with data from literature ob...

Objective: This study evaluated the influence of Nd:YAG laser on the evaporation degree (ED) of the solvent components in total-etch and self-etch adhesives. Materials and methods: The ED of Gluma Comfort Bond (Heraeus-Kulzer) one-step self-etch adhesive, and Adper Single Bond 2 (3M ESPE), and XP Bond (Dentsply) total-etch adhesives was determin...

This work is focused on the evaluation of the photophysical properties of protoporphyrin-IX derivatives with different alkyl chains. The goal of this work is to understand the physicochemical properties and select prototypes of photosensitizers for photodynamic therapy. Solvents with different dielectric constants were used to obtain relevant data...

In this work, the study on the influence of binary mixtures of solvents (water-acetonitrile, water-ethanol and water-glycerol) upon the spectroscopic properties of methylene blue (MB) was done. In addition, the photophysical characterization of the MB in different concentrations in the solvent mixtures was done. In the mixtures, the increase in the...

This work studied the fluorescent and solvatochromic properties of coumarin and its derivatives aiming to contribute in the elucidation of the excited state behavior of the molecule in solvent mixtures. This approach has been developed through a set of measurements involving different solvent ratios, which present distinct dielectric constants. The...

The present study aims the development and application of an electrochemical method for simple coumarin determination in aqueous media by using a boron-doped diamond electrode (BDDE). The studies were carried out at pH 8.0 by cyclic voltammetry (CV) and registered an irreversible reduction process controlled by diffusion with the peak potential rec...

SUMMARY The aim of this study was to evaluate the fluorescence intensity of different composite resins and compare those values with the fluorescence intensity of dental tissues. Different composite resins were used to make 10 discs (2 mm in depth and 4 mm in diameter) of each brand, divided into groups: 1) Z (Filtek Z350, 3M ESPE), 2) ES (Esthet-X...

In this study, a method for electroanalytical determination of carbendazim (CBZ) and fenamiphos (FNP) in natural and spiked water was developed using square wave voltammetry in Na2HPO4 0.1 mol L− 1 as supporting electrolyte. The calibration curve for carbendazim detection presented good linearity in the concentration range of 0.50 to 15.0 μM, with...

This work used dispersive Raman spectroscopy to evaluate acetaminophen in commercially available formulations as an analytical methodology for quality control in the pharmaceutical industry. Raman spectra were collected using a near-infrared dispersive Raman spectrometer (830 nm, 50 mW, 20 s exposure time) coupled to a fiber optic probe. Solutions...

Is well known that obesity has increased significantly in recent times and therefore many dietary supplements, synthetic or natural, have been proposed in order to prevent and/or to treat obesity or overweight. Chitosan, a polysaccharide with ability to act as a carrier and to absorb fat, has been used for this purpose. However, interactions with o...

Some aspects of the energy transfer processes between poly(9,9′-dihexylfluorene-2,2-dyil) and MEH-PPV in solutions of good and poor solvents and in solid state blends are addressed. The resonant non-radiative energy transfer in solution is discussed in terms of the Förster dynamic model and using steady-state and dynamical photoluminescence we obse...

Chlorophyll (Mg-Chl) and its derivatives, zinc chlorophyll (Zn-Chl), copper chlorophyll (Cu-Chl), pheophytin (Pheo), pheophorbide (Pheid), and zinc chlorophyllide (Zn-Chld), were studied as to their acid-base equilibrium properties, hydrophobicity, stability, binding, and relative localization in neutral surfactant micellar systems. The stability o...

This work describes the behavior of 1,6-diphenyl-1,3,5-hexatriene (DPH) in ethanol/water mixtures. The dependence of DPH photophysical properties (absorption and fluorescence emission) on the water percentage in ethanol indicates that DPH undergoes self-aggregation processes in solvent conditions above a critical water content. Evidence such as an...

Chlorophyll compounds and their derivatives containing metal or phytyl chain can be used as photosensitizer in photodynamic inactivation of microorganisms (PDI). So, the physicochemical properties and antimicrobial effect of chlorophyll derivatives were investigated: Mg-chlorophyll (Mg-Chl), Zn-chlorophyll (Zn-Chl), Zn-chlorophyllide (Zn-Chlde), Cu...

Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the pKa determination and the attribution of each group to the corresponding pKa value is a very important feature. Attempts to obtain reliable pKa through the potentiometry titratio...

Objectives: Evaluate the fluorescence intensity (FI) of different composite-resins (CR) and compare it to dental tissues FI. Methods: CR were used to make ten discs (2mm/depth and 4mm/diameter) of each brand, divided into groups: For the groups: Z (Filtek-Z350/3MEspe); ES (Esthet-X/Dentsply); A (Amelogen-Plus/Ultradent) and DVS (Durafill- VS/Heraeu...

Benzoporphyrin monoacid derivatives, here named B3A and B3B, are promising new drugs for photodynamic therapy. Although both isomers show interesting characteristics as photosensitizing compounds, they have some distinct physicochemical properties such as the tendency to self-aggregate in water-rich media. Because pH drives the presence of each spe...

Obesity is a serious health problem and its prevalence has increased over the years. Studies have assessed the polysaccharide chitosan as anti-obesity supplement due to its ability to absorb fats. However, this property may cause the interaction of chitosan with essential substances for the proper functioning of the body, such as vitamins. In this...

A simple, rapid and effective analytical method based on fluorescence spectroscopy for the determination of coumarin in pharmaceutical formulations without pre-treatment or pre-concentration step was development. Coumarin had maximum excitation and emission at 310 nm and 390 nm, respectively. Optimum conditions for the detection of coumarin were in...

Nowadays, the synthetic dyes (as erythrosine, ponceau and tartrazina) and natural colourants (as annatto, paprika, curcuma and anthocyanin) are indispensable in the food, pharmaceutical and cosmetics applications. However, the use of natural colourant has been considered safer for human consumption then synthetic dye. For practical applications of...

Fluorescein (C.I. Solvent Yellow 94) contains three acid-base groups that lead to a protolytic equilibrium involving four species namely, dianionic, monoanionic, neutral and cationic. Since these species display superimposed bands in their electronic absorption spectra and close pKa values, the determination of pKa using traditional methods is comp...

INFLUENCE OF DIFFERENT WATER-ETHANOL SOLVENT SYSTEMS ON THE SPECTROSCOPIC AND PHYSICO-CHEMICAL PROPERTIES OF THE MACROCYCLIC COMPOUNDS PHEOPHYTIN AND CHLOROPHYLL a. This work focus on the influence of solvent on the photophysical properties of chlorophyll a and pheophytin. Both compounds are related to the photosynthesis process and are considered...

The absorption spectra of DPH at fixed concentration do not change with water content in organic solvents. It exhibits monomer bands, such as those obtained in ethanol. The absorption did not change for solutions up to 54 and 46% of water in ethanol and DMSO, respectively, for [DPH]=5.0 × 10-6 mol L-1 at 30°C. However, at the same experimental cond...

Infections caused by Candida albicans are of increasing concern, especially considering immunodepressed patients. The toxicity of most antifungal agents, the great number of cases with recidives, as well as the emergence of resistant samples has provoked the evaluation of new forms of therapy. In this context, the photodynamic therapy (PDT) present...

Infections caused by Candida albicans are of increasing concern, especially considering immunodepressed patients. The toxicity of most antifungal agents, the great number of cases with recidives, as well as the emergence of resistant samples has provoked the evaluation of new forms of therapy. In this context, the photodynamic therapy (PDT) present...

This work focus on the influence of solvent on the photophysical properties of chlorophyll α and pheophytin. Both compounds are related to the photosynthesis process and are considered prototypes of photosensitizers in Photodynamic Therapy. Fluorescence measurements were developed using water/ethanol mixtures at different compositions, since both s...

Potentially useful stead-state fluorimetric technique was used to determine the critical micellar concentrations (CMC1 and CMC2) for two micellar media, one formed by SDS and the other by SDS/Brij 30. A comparative study based on conductimetric and surfacial tension measurements suggests that the CMC1 estimated by the fluorimetric method is lower t...

No presente estudo, o papel de diferentes centros metálicos (magnésio, zinco e cobre) sobre o caráter hidrofílico de metaloclorofilas foi avaliado. O solvatocromismo, assim como o processo de agregação para esses compostos, em misturas água/etanol foram avaliados usando medidas de fluorescência e de espalhamento de luz ressonante (ELR), visando car...

Este trabalho descreve as propriedades fotofísicas (espectros de excitação e de fluorescência, rendimento quântico e tempo de meia-vida de fluorescência) do poli(2,7-9,9'diexil-fluoreno-diil) em soluções diluídas, de quatro solventes (tolueno, tetraidrofurano, clorofórmio e acetato de etila) e no estado sólido. Os espectros de fotoluminescência são...

The microenvironment formed by lauroyl and stearoyl derivatives of chitosan in solution has been studied using two fluorescent probes, pyrene and nabumetone. Existence or not of microdomains formed by polymolecular associations, the inherent hydrophobicity of them in aqueous solution, and the influence of degree of substitution (DS) of derivatives...

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....

Atactic poly(methacrylic acid) labeled with acridine and Nile blue (NB) were studied by photophysical techniques in bulk solid state and in solution-cast films over different surfaces (glass, ITO, and polymethylmethacrylate). In the systems with both dyes, energy transfer from acridine to NB occurs with an efficiency depending on the type of substr...

Solid polymeric electrolytes based on poly(vinylpyrrolidone) plasticized with dioctylftalate and containing LiCl salt were obtained. The samples were prepared as membranes in the co-polymerization process of vinylpyrrolidone (VP) with methacrylic acid (20% in VP mass) and tetraethylene glycol diacrylate (10% in VP mass) as cross-linking agent. The...

Here we present an overview of electroluminescent devices that use conjugated polymers as the active media. The principal components of the devices are described and we show some examples of conjugated polymers and copolymers usually employed in polymeric light emitting devices (PLED). Some aspects of the photo and electroluminescence properties as...

Here we present an overview of electroluminescent devices that use conjugated polymers as the active media. The principal components of the devices are described and we show some examples of conjugated polymers and copolymers usually employed in polymeric light emitting devices (PLED). Some aspects of the photo and electroluminescence properties as...

Here we present an overview of electroluminescent devices that use conjugated polymers as the active media. The principal components of the devices are described and we show some examples of conjugated polymers and copolymers usually employed in polymeric light emitting devices (PLED). Some aspects of the photo and electroluminescence properties as...

The electrosynthesis of a soluble poly(fluorenylene vinylene) derivative, namely poly(9,9-dioctyl-2,7-fluorenylene vinylene) (PDO27FV), its characterization, photophysical properties and electrochemistry are reported in this work. Photophysical studies indicate a strong dependence on the solvent employed, suggesting a highly polar excited state. Th...

The native fluorescence of paracetamol (PA) in the solid state is demonstrated, allowing the development of a rapid, simple and rugged method for direct analysis of pharmaceutical formulations. It is easily adaptable to any spectrofluorimeter, and no chemical treatment of the sample is needed. The fluorescence measurements (λex = 333 nm; λem = 382...

Phenol recovery from wastewaters is a crucial task in the chemical process area, for both economical and environmental reasons, since phenol is a high added value product but, also, highly toxic. Reactive distillation is being proposed as an alternative process for eliminating phenol from water. However, before studying the process, it is necessary...

Electronic and vibrational spectra of 9-aminoacridine and acridine-9-N-methacrylamide are measured and compared with theoretical values obtained by quantum chemical calculations. Geometry, electronic transitions, charge distribution, population analysis, and the IR normal modes of this new dye and of its precursor have been computed by density func...