Effect of different dye solutions on the evaluation of the sealing ability of Mineral Trioxide Aggregate.

Alkaline materials have shown incompatibility with methylene blue dye in leakage experiments. The goal of the present study was to analyze the effect of different dyes on the evaluation of the apical sealing ability of Mineral Trioxide Aggregate root-end fillings. Fifty-six extracted human canines were submitted to root canal instrumentation and obturation. After apical resection, retrograde cavities were prepared and teeth were randomly divided into four experimental (n = 13) and two control groups (n = 2). The following root-end filling materials were used: groups 1 and 2--Pro Root MTA (Dentsply), groups 3 and 4--zinc oxide-eugenol cement (ZOE). Teeth in groups 1 and 3 were immersed in 2% methylene blue solution, while teeth in groups 2 and 4 were immersed in 0.2% rhodamine B in a reduced pressure environment for 48 hours. Teeth were then longitudinally sectioned and leakage was evaluated. Results were submitted to statistical analysis (ANOVA and Tukey's test). Group 1 presented the least leakage (p < 0.05). It was concluded that the evaluation of the sealing ability of MTA is influenced by the dye used, since this material presented better sealing ability when evaluated with Methylene Blue, but was similar to ZOE when evaluated with rhodamine B.

Electrooptic proprieties of layer-by-layer films of a azobenzene containing copolymer

The methacrylic copolymer functionalized with the azo chromophore 4-[N-ethyl-N-(2-hydroxiethyl)]-amino-2′-chloro-4-nitroazobenzene (MMADR13), in its polyelectrolyte form, can be used to fabricate thin films by the layer-by-layer (LbL) technique just if one alternates this anionic polyelectrolyte with a cationic polyelectrolyte such as poly(allylamine hydrochloride) (PAH). Since PAH does not present any particular optical functionality, the main final film feature will came from the side chain DR13 azo-chromophore group due to its large nonlinear optical properties and photoisomerization capabilities. This work reports the electrooptic activity of MMADR13/DR13 LBL films, which arises from the high hiperpolarizability about the azo side chain group.

Composition of constitutive heterochromatin of Pseudonannolene strinatii Mauriès, 1974 (Diplopoda, Spirostreptida) analyzed by AT/CG specific fluorochromes.

Triple staining with fluorochromes (DA/DAPI/CMA) and C-banding were used to characterize the composition of Pseudonannolene strinatii heterochromatin. C-banding showed C+ bands of different labeling intensity on chromosomes 1 and 2 in some cells. Fluorochrome staining revealed DAPI+ regions corresponding to the C-banding pattern, indicating that the heterochromatin of this species is abundant in AT-rich sequences.

Excipientes de medicamentos e as informações da bula

Aim: To evaluate the presence of preservatives, dyes, sweeteners and flavouring substances in 73 pharmaceutical preparations of 35 medicines for oral administration, according to drug labeling information about the excipients. Methods: 35 medications were selected, both over-the-counter and prescription durgs, marketed in Brazil. The sample included: analgesic/antipyretic, antimicrobial, mucoregulatory, cough and cold, decongestant, antihistamine, bronchodilator, corticosteroid, antiinflammatory and vitamin medications. We collected data on 73 preparations of these drugs, according to drug labeling information regarding preservatives, dyes, sweeteners and flavourings. Results: Methylparaben and propylparaben were the most common preservatives found (43% and 35.6% respectively). The most common sweeteners were: sucrose (sugar) (53.4%), sodium saccharin (38.3%) and sorbitol (36.9%). Twenty-one medicines (28,7%) contained two sweeteners. Colourless medicines predominated (43.8%), followed by those with sunset yellow dye (FD&C yellow no. 6) (15%). Five products (6.8%) contained more than one colour agent. Tartrazine (FD&C yellow no. 5) was present in seven preparations (9.5%). Fruit was the most common flavouring found (83%). Labelings of drugs which contained sugar frequently omitted its exact concentration (77%). Of the four labelings of medicines which contained aspartame, two did not warn patients regarding phenylketonuria. Conclusions: Omission and inacuracy of drug labeling information on pharmaceutical excipients may expose susceptible individuals to adverse reactions caused by preservatives and dyes. Complications of inadvertent intake of sugar-containing medicines by diabetics, or aspartame intake by patients with phenylketonuria may also occur.

The influence of zero-value subtraction on the performance of two laser fluorescence devices for detecting occlusal caries in vitro

Background. The aim of this study was to evaluate the influence of zero-value subtraction on the performance of two laser fluorescence (LF) devices developed to detect occlusal caries. Methods. The authors selected 119 permanent molars. Two examiners assessed three areas (cuspal, middle and cervical) of both mesial and distal portions of the buccal surface and one occlusal site using an LF device and an LF pen. For each tooth, the authors subtracted the value measured in the cuspal, middle and cervical areas in the buccal surface from the value measured in the respective occlusal site. Results. The authors observed differences among the readings for both devices in the cuspal, middle and cervical areas in the buccal surface as well as differences for both devices with and without the zero-value subtraction in the occlusal surface. When the authors did not perform the zero-value subtraction, they found statistically significant differences for sensitivity and accuracy for the LF device. When this was done with the LF pen, specificity increased and sensitivity decreased significantly. Conclusions. For the LF device, the zero-value subtraction decreased the sensitivity. For this reason, the authors concluded that clinicians can obtain measures with the LF device effectively without using zero-value subtraction. For the LF pen, however, the absence of the zero-value subtraction changed both the sensitivity and specificity, and so the authors concluded that clinicians should not eliminate this step from the procedure. Clinical Implications. When using the LF device, clinicians might not need to perform the zero-value subtraction; however, for the LF pen, clinicians should do so.

The mechanism of dephosphorylation of bis(2,4-dinitrophenyl) phosphate in mixed micelles of cationic surfactants and lauryl hydroxamic acid

(Figure Presented) Mixed micelles of cetyltrimethylammonium bromide (CTABr) or dodecyltrimethylammonium bromide (DTABr) and the α-nucleophile, lauryl hydroxamic acid (LHA) accelerate dephosphorylation of bis(2,4-dinitrophenyl) phosphate (BDNPP) over the pH range 4-10. With a 0.1 mole fraction of LHA in DTABr or CTABr, dephosphorylation of BDNPP is approximately 10 4-fold faster than its spontaneous hydrolysis, and monoanionic LHA - is the reactive species. The results are consistent with a mechanism involving concurrent nucleophilic attack by hydroxamate ion (i) on the aromatic carbon, giving an intermediate that decomposes to undecylamine and 2,4-dinitrophenol, and (ii) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement yielding a series of derivatives including N,N-dialkylurea, undecylamine, undecyl isocyanate, and carbamyl hydroxamate. © 2009 American Chemical Society.

CdMoO 4 synthesized by a microwave-assisted hydrothermal method and their photoluminescence and photocatality properties

In this work CdMoO 4 nanoparticles were obtained under hydrothermal conditions using microwave radiation (2.45 GHz) (MH) at 100°C for different times. These powders were analyzed by X-ray diffraction (XRD), Field-emisson gum scanning electron microscopy (FEG-SEM), Ultraviolet-visible (UV-vis) absorption spectroscopy and photoluminescence (PL) measurements. XRD pattern confirmed that the pure CdMoO 4 phases were obtained. FEG-SEM powders present large-scale and homogeneous particles with microspheres-like morphology. UV-vis results were employed to determine the optical band gap these materials. Also, it showed existence of photoluminescence (PL) emission in the green wavelength range of 540-546 nm. Photocatalytic activity of CdMoO 4 nanocrystals was examined by monitoring the degradation of rhodamine B dye.

Determination of Sudan II dye in ethanol fuel by chromatographic and electroanalytical methods

Chromatographic and electroanalytical methods were developed to detect and quantify Sudan II (SD-II) dye in fuel ethanol samples. Sudan II is reduced at +0.50 V vs. Ag/AgCl on a glassy carbon electrode using Britton-Robinson buffer (pH 4.0) and N,N-dimethylformamide (70:30, v/v) + sodium dioctyl sulfosuccinate surfactant as supporting electrolyte, due to the azo group. This is the basis for its determination by square-wave voltammetry (SWV). Using the optimized conditions, it is possible to get a linear calibration curve from 3.00×10-6 to 1.80×10-5 mol L-1 (r = 0.998) with limits of detection (LOD) and quantification (LOQ) of 2.05×10-6 and 6.76×10-6 mol L-1, respectively. In addition, the hydroxyl substituent in the SD-II dye is also oxidized at +0.85 V vs. Ag/AgCl, which was conveniently used for its determination by high-performance liquid chromatography coupled to electrochemical detection (HPLC-ED). Under the optimized condition, the SD-II dye was eluted and separated using a reversed-phase column (cyanopropyl, CN) using isocratic elution with the mobile phase containing acetonitrile and aqueous lithium chloride (5.00×10-4 mol L-1) at 70:30 (v/v) and a flow rate of 1.2 mL min-1. Linear calibration curves were obtained from 3.00×10-7 to 2.00×10-6 mol L-1 (r = 0.999) with LOD and LOQ of 3.10×10-8 and 1.05×10-7 mol L-1, respectively. Both methods were simple, fast and suitable to detect and quantify the dye in fuel ethanol samples at recovery values between 83.0 to 102% (SWV) and 88.0 to 112% (HPLC-ED) with satisfactory precision and accuracy.

Cranial osteology of Picini (Aves: Piciformes: Picidae)

The Picini is composed of 26 species of woodpeckers from the old world that are grouped into seven genera. Given the absence of detailed studies on the cranial osteology of the Picini, the purpose of this study is to describe the cranial osteology of 14 species of Picini from six genera and to compare these species with each other, with other species of woodpeckers and with other bird groups. The results of the analysis of the bone structures of the skull of the Picini indicate that there are seven outstanding characteristic of bones involved in the functional mechanistics of the jaw apparatus. In the ossa cranii, these include the frontal overhang, the postorbital process, the extension of the parietal versus the frontal region and the temporal fossa. In the ossa faciei, these include the rostral expansion of the pterygoid, the ventral palatine fossa and the orbital process of the quadrate bone. For all of the structures associated with the cranial osteology of the investigated species, there is a clear distinction between the species of the genus Picus and the other species studied. Blythipicus rubiginosus, Chrysocolaptes lucidus, Reinwardtipicus validus, Gecinulus viridis and the species of the genus Dinopium exhibit additional particularities. © 2012 The Royal Swedish Academy of Sciences.

Thermal studies of chitin-chitosan derivatives

New poly(azo) amino-chitosan compounds were obtained from the azo coupling reaction of N-benzyl chitosan and diazonium salts. The thermal behavior of these compounds was studied by thermogravimetric analysis (TG), differential thermogravimetric analysis (DTG), TG coupled with a Fourier-transform infrared, and differential scanning calorimetry (DSC). TG/DTG curves of chitin-chitosan polymer showed two thermal events attributed to water loss and decomposition of the polysaccharide after cross-linking reactions. Thermal analysis of the poly(azo) amino-chitosan compounds showed that the decomposition temperatures decreased when compared to the starting chitin-chitosan and N-benzyl chitosan. DSC results showed an agreement with the TG/DTG analyses. Thermal behavior of poly(azo) amino-chitosans suggest that these compounds could be considered as potential thermal sensors. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Acid dye biodegradation using saccharomyces cerevisiae immobilized with polyethyleneimine-treated sugarcane bagasse

Chemical reagents used by the textile industry are very diverse in their composition, ranging from inorganic compounds to polymeric compounds. Strong color is the most notable characteristic of textile effluents, and a large number of processes have been employed for color removal. In recent years, attention has been directed toward various natural solid materials that are able to remove pollutants from contaminated water at low cost, such as sugarcane bagasse. Cell immobilization has emerged as an alternative that offers many advantages in the biodegradation process, including the reuse of immobilized cells and high mechanical strength, which enables metabolic processes to occur under adverse conditions of pH, sterility, and agitation. Support treatment also increases the number of charges on the surface, thereby facilitating cell immobilization processes through adsorption and ionic bonds. Polyethyleneimine (PEI) is a polycationic compound known to have a positive effect on enzyme activity and stability. The aim of the present study was to investigate a low-cost alternative for the biodegradation and bioremediation of textile dyes, analyzing Saccharomyces cerevisiae immobilization in activated bagasse for the promotion of Acid Black 48 dye biodegradation in an aqueous solution. A 1 % concentration of a S. cerevisiae suspension was evaluated to determine cell immobilization rates. Once immobilization was established, biodegradation assays with free and immobilized yeast in PEI-treated sugarcane bagasse were evaluated for 240 h using UV-vis spectrophotometry. The analysis revealed significant relative absorbance values, indicating the occurrence of biodegradation in both treatments. Therefore, S. cerevisiae immobilized in sugarcane bagasse is very attractive for use in biodegradation processes for the treatment of textile effluents. © 2012 Springer Science+Business Media Dordrecht.

Growth mechanism and photocatalytic properties of SrWO4 microcrystals synthesized by injection of ions into a hot aqueous solution

This paper reports our initial research to obtain SrWO4 microcrystals by the injection of ions into a hot aqueous solution and their photocatalytic (PC) properties. These microcrystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinements and Fourier transform (FT)-Raman spectroscopy. The shape and average size of these SrWO 4 microcrystals were observed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). In addition, we have investigated the PC activity of microcrystals for the degradation of rhodamine B (RhB) and rhodamine 6G (Rh6G) dyes. XRD patterns, Rietveld refinement data and FT-Raman spectroscopy confirmed that SrWO4 microcrystals have a scheelite-type tetragonal structure without deleterious phases. FT-Raman spectra exhibited 12 Raman-active modes in a range from 50 to 1000 cm-1. FE-SEM and TEM images suggested that the SrWO4 microcrystals (rice-like - 95%; star-, flower-, and urchin-like - 5%) were formed by means of primary/secondary nucleation events and self-assembly processes. Based on these FE-SEM/TEM images, a crystal growth mechanism was proposed and discussed in details in this work. Finally, a good PC activity was first discovered of the SrWO4 microcrystals for the degradation of RhB after 80 min and Rh6G after 50 min dyes under ultraviolet-light, respectively. © 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder.

Effect of experimental photopolymerized coatings on the hydrophobicity of a denture base acrylic resin and on Candida albicans adhesion

Objective: This study investigated the effect of experimental photopolymerized coatings, containing zwitterionic or hydrophilic monomers, on the hydrophobicity of a denture base acrylic resin and on Candida albicans adhesion. Methods: Acrylic specimens were prepared with rough and smooth surfaces and were either left untreated (control) or coated with one of the following experimental coatings: 2-hydroxyethyl methacrylate (HE); 3-hydroxypropyl methacrylate (HP); and 2-trimethylammonium ethyl methacrylate chloride (T); and sulfobetaine methacrylate (S). The concentrations of these constituent monomers were 25%, 30% or 35%. Half of the specimens in each group (control and experimentals) were coated with saliva and the other half remained uncoated. The surface free energy of all specimens was measured, regardless of the experimental condition. C. albicans adhesion was evaluated for all specimens, both saliva conditioned and unconditioned. The adhesion test was performed by incubating specimens in C. albicans suspensions (1 × 10 7 cell/mL) at 37 °C for 90 min. The number of adhered yeasts were evaluated by XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-5-[{phenylamino} carbonyl]-2H-tetrazolium-hydroxide) method. Results: For rough surfaces, coatings S (30 or 35%) and HP (30%) resulted in lower absorbance values compared to control. These coatings exhibited more hydrophilic surfaces than the control group. Roughness increased the adhesion only in the control group, and saliva did not influence the adhesion. The photoelectron spectroscopy analysis (XPS) confirmed the chemical changes of the experimental specimens, particularly for HP and S coatings. Conclusions: S and HP coatings reduced significantly the adhesion of C. albicans to the acrylic resin and could be considered as a potential preventive treatment for denture stomatitis. © 2012 Elsevier Ltd.

Bothrops leucurus venom induces nephrotoxicity in the isolated perfused kidney and cultured renal tubular epithelia

Bites from snake (Bothrops genus) cause local tissue damage and systemic complications, which include alterations such as hemostatic system and acute renal failure (ARF). Recent studies suggest that ARF pathogenesis in snakebite envenomation is multifactorial and involves hemodynamic disturbances, immunologic reactions and direct nephrotoxicity. The aim of the work was to investigate the effects of the Bothrops leucurus venom (BlV) in the renal perfusion system and in cultured renal tubular cells of the type MDCK (Madin-Darby Canine kidney). BlV (10 μg/mL) reduced the perfusion pressure at 90 and 120 min. The renal vascular resistance (RVR) decreased at 120 min of perfusion. The effect on urinary flow (UF) and glomerular filtration rate (GFR) started 30 min after BlV infusion, was transient and returned to normal at 120 min of perfusion. It was also observed a decrease on percentual tubular transport of sodium (%TNa+) at 120 min and of chloride (%TCl-) at 60 and 90 min. The treatment with BlV caused decrease in cell viability to the lowest concentration tested with an IC50 of 1.25 μg/mL. Flow cytometry with annexin V and propidium iodide showed that cell death occurred predominantly by necrosis. However, a cell death process may involve apoptosis in lower concentrations. BlV treatment (1.25 μg/mL) led to significant depolarization of the mitochondrial membrane potential and, indeed, we found an increase in the expression of cell death genes in the lower concentrations tested. The venom also evoked an increase in the cytosolic Ca2+ in a concentration dependent manner, indicating that Ca2+ may participate in the venom of B. leucurus effect. The characterization of the effects in the isolated kidney and renal tubular cells gives strong evidences that the acute renal failure induced by this venom is a result of the direct nephrotoxicity which may involve the cell death mechanism. © 2012.