Influence of chlorhexidine in cavities prepared with ultrasonic or diamond tips on microtensile bond strength

This study evaluated the effect of chlorhexidine (CLX) in cavities prepared with either ultrasound-mounted CVDentUS diamond tips or conventional diamond burs on dentin bond strength after 24 h and 180 days. Forty-eight dentin surfaces from sound third molars were flattened and divided into four groups (n = 12), according to the type of cavity preparation (CVDentUS ultrasound tip or conventional diamond) and with or without 2% CLX (Consepsis) treatment. After application of the adhesive system (Clearfil SE Bond), microhybrid composite resin blocks (Charisma) were made on the dentin surface in increments. After 24 h, the specimens were sectioned into stick-shaped samples with an adhesive interface of approximately 1 mm². From each tooth, half of the sticks were evaluated after 24 h of storage in distilled water and the other half after 180 days, using a universal testing machine. Three-way analysis of variance showed no significant triple interactions (p = 0.722) or double interactions between factors. Higher bond strength values were observed with the use of ultrasonic tips (p = 0.019), irrespective of whether or not CLX was applied in either time period. No difference in bond strength values was observed in terms of CLX application (p = 0.581). No significant difference in bond strength values was shown after storage for 24 h or 180 days (p = 0.302). In conclusion, the ultrasonic tips promoted greater bond strength to dentin, irrespective of whether or not CLX was applied, and storage time.     

Epoxysilane as adhesion promoter in duplex system

Coatings are one of the most used protection methods for metals. Metallic coatings, such as zinc and its alloys, are used to protect steel in mild corrosive environments. In aggressive environments, on the other hand, organic coatings must be employed in the so-called duplex systems. However, the galvanized steel/organic coating adhesion is a problem and many attempts had been done to solve it with the incorporation of a chromate-based or phosphate-based interlayer. Nowadays, the use of these compounds is questioned due to their environmental impact and new adhesion promoters, like silanes, are being investigated. The aim of this paper was to study the adhesion and the anticorrosive behavior of a duplex system with a layer of glycidoxypropyltrimethoxysilane (γ-GPS) between the zinc and the coating. Polarization tests and corrosion potential measurements were done on the γ-GPS/galvanized steel to select the better anticorrosive pretreatment conditions for the application of an organic traditional paint. Dried and wet adhesion of the coating to the pretreated substrate was studied by the standard tape test. Salt spray test and electrochemical noise technique were employed to study the corrosion behavior of the duplex systems. Results showed that the films of γ-GPS formed on galvanized steel diminished the corrosion current of the metal, but they do not protect the substrate by a barrier effect. The incorporation of the pretreatment in the duplex system increased the adhesion of the paint, especially when the pretreated substrate was cured 1?h at 200?°C.     

Electrochemical oxidation of methyl orange azo dye at pilot flow plant using BDD technology

Solutions of methyl orange azo dye were degraded by electrochemical oxidation using a 3 L flow plant with a boron-doped diamond (BDD)/stainless steel cell operating at constant current density, ambient temperature and liquid flow rate of 12 L min^?1. A 2³ factorial design considering the applied current density, azo dye concentration and electrolysis time as variable independents was used to analyze the process by response surface methodology. LC–MS analysis revealed the formation of seven oxidation products from the cleavage of the NN group of the dye, followed by deamination, formation of a nitro group and/or desulfonation of the resulting aromatics.     

Viability of a native isolate of Lactobacillus brevis in a fermented milky drink

The objective of this research was to test the viability of a native isolate of Lactobacillus brevis in two fermented milky drinks: a drink without prebiotic ingredient and another drink with oat flour (0.5%, p/v) as prebiotic ingredient. The viability of L. brevis was tested at 7, 14, and 21 after inoculation. Drink pH and lactic acid concentration was measured as a function of time (2, 7, 14, and 21 days after inoculation). The isolate was viable in both drinks because its counting plates was higher than 10(6) CFU/mL until day 21st. Between the 7th and 14th day, the rate of growth was higher in the drink that included oat flour, however, at the day 21st the colony density was similar in both drinks.     

Organic phase PPO biosensor based on hydrophilic films of electropolymerized polypyrrole

We described herein, the construction of an organic phase enzyme electrode (OPEE) via polyphenol oxidase (PPO) entrapment within a hydrophilic polypyrrole film electrogenerated from on a new bispyrrolic derivative (1) containing a long hydrophilic spacer. The so-called “adsorption step procedure” was adopted for the preparation of the organic phase PPO biosensor. The amperometric detection of catechol was carried out in anhydrous chloroform at −0.2 V versus Ag/AgCl. The electroanalytical parameters of the biosensor strongly depend on its configuration and on the hydration state of the enzyme matrix. The best sensitivity obtained for catechol in chloroform was 15.6 mA M⁻¹ cm⁻².     

Crosslinking reactions and swelling behavior of matrices based on N-acryloyl-TRIS(hydroxymethyl)aminomethane

Summary In this study, new hydrogels in rod shape were prepared from N-acryloyl-TRIS(hydroxymethyl)aminomethane (NAT) using ethylene glycol dimethacrylate (EGDMA) or N,N’methylenebisacrylamide (BIS) as crosslinking agent, dimethylformamide (DMF) as solvent and benzoyl peroxide (BPO) as initiator. In most cases, 2-hydroxyethyl methacrylate (HEMA), acrylamide (Aam) or acrylic acid (Aac) were used as co-monomers. The polymeric matrices obtained by free radical polymerization exhibited different properties by changing crosslinker, crosslinker concentration, co-monomer and initial NAT/co-monomer mole ratio. Besides, hydrogels from HEMA, Aam and Aac with BIS in absence of NAT were prepared under the same experimental reaction conditions in order to compare the properties of these products with those synthesized from NAT and the respective co-monomers. Some of the final products were selected to perform urea release assays, conducted through swelling-controlled release. Urea was chosen as “model” plant fertilizer agent.     

Design and Characterization of Myristoylated and Non-Myristoylated Peptides Effective against Candida spp. Clinical Isolates

The increasing resistance of fungi to antibiotics is a severe challenge in public health, and newly effective drugs are required. Promising potential medications are lipopeptides, linear antimicrobial peptides (AMPs) conjugated to a lipid tail, usually at the N-terminus. In this paper, we investigated the in vitro and in vivo antifungal activity of three short myristoylated and non-myristoylated peptides derived from a mutant of the AMP Chionodracine. We determined their interaction with anionic and zwitterionic membrane-mimicking vesicles and their structure during this interaction. We then investigated their cytotoxic and hemolytic activity against mammalian cells. Lipidated peptides showed a broad spectrum of activity against a relevant panel of pathogen fungi belonging to Candida spp., including the multidrug-resistant C. auris. The antifungal activity was also observed vs. biofilms of C. albicans, C. tropicalis, and C. auris. Finally, a pilot efficacy study was conducted on the in vivo model consisting of Galleria mellonella larvae. Treatment with the most-promising myristoylated peptide was effective in counteracting the infection from C. auris and C. albicans and the death of the larvae. Therefore, this myristoylated peptide is a potential candidate to develop antifungal agents against human fungal pathogens.     

Nutritional knowledge and consumption frequency of foods--a case study

The relationship between nutritional knowledge and the consumption frequency of preferred food-types was studied among one sample of Uruguayan consumers. A locally-adapted version of Parmenter & Wardle's General Nutrition Knowledge Questionnaire and a food consumption survey based on 39 food groups were completed by a total of 270 participants. Cluster Analysis enabled the identification of two clusters showing different levels of nutritional knowledge--cluster 1 (n = 177) and cluster 2 (n = 93), providing an average of 73.6% and 52.9% of correct answers, respectively. These clusters differed significantly (p < or = 0.05) in age and educational distribution--cluster 1 was composed mainly by older adults and persons with a higher educational level. A number of areas were identified where nutritional knowledge was extremely poor, as was the case with the recommended daily fruit and vegetable intake and the caloric content of the nutrients. Overall, nutritional knowledge was found to have a positive influence on food preferences and consumption frequency, those participants with a higher nutritional knowledge reporting a higher consumption of fruits, vegetables and low-fat products, in addition to a lower consumption of high-fat and high-sugar foods.