Polysaccharide‐based membranes loaded with erythromycin for application as wound dressings

In this study, the antibiotic erythromycin (Ery) was incorporated into chitosan (Ch)–alginate (A) and Ch–xanthan (X) membranes with the aim of using them as bioactive wound dressings. Drug incorporation was performed by direct addition (DA) to the polysaccharide mixture and by membrane impregnation in solution (IS). A higher incorporation efficiency was obtained for DA, but higher amounts of drug were loaded into membranes by the IS method (maxima ≈ 2.1 and 0.7 g/g for Ch–X and Ch–A, respectively) because the initial concentration of drug could be higher than that in the DA method. Ery release in phosphate‐buffered saline was slow, reaching about 12 and 32 mg of drug/g of membrane in 60 h for Ch–X and 4 and 16 mg/g for Ch–A by the DA and IS methods, respectively. With formulations prepared with IS, the required therapeutic dosage was reached within 60 h, whereas for those incorporating the drug by DA, prolonged use would be required. Both membrane types behaved as drug reservoirs, providing continuous antibiotic release to the wound site. Formulations with higher drug contents showed effective antibacterial activity against two species of bacteria commonly found in skin lesions, Staphylococcus aureus and Pseudomonas aeruginosa, and were thus potentially capable of protecting the wound site from bacterial attack. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43428.     

Molecular Insights on the Role of (CTA+)(SiO−) Ion Pair into the Catalytic Activity of [CTA+]–Si–MCM-41

Topics in Catalysis - In this work, a theoretical study in conjunction with a spectroscopic analysis by FTIR were carried out in order to obtain molecular insights on the role of...     

Maternal Flaxseed Oil During Lactation Enhances Bone Development in Male Rat Pups

Flaxseed oil is an alpha linolenic acid source important in the growth and body development stage; furthermore, this acid acts on adipose tissue and bone health. The aim of this study was to evaluate body composition, fatty acid composition, hormone profile, retroperitoneal adipocyte area and femur structure of pups at weaning, whose mothers were fed a diet containing flaxseed oil during lactation. After birth, pups were randomly assigned: control (C, n = 12) and flaxseed oil (FO, n = 12), rats whose mothers were treated with diet containing soybean or flaxseed oil. At 21 days, the pups were weaned and body mass, length, body composition, biochemical parameter, leptin, osteoprotegerin, osteocalcin, fatty acids composition, intra‐abdominal fat mass and femur structure were analyzed. FO showed (p < 0.05): higher body mass (+12 %) and length (+9 %); body fat mass (g, +45 %); bone mineral density (+8 %), bone mineral content (+55 %) and bone area (+35 %), osteocalcin (+173 %) and osteoprotegerin (+183 %). Arachidonic acid was lower (p < 0.0001), alpha‐linolenic and eicosapentaenoic were higher (p < 0.0001). Intra‐abdominal fat mass was higher (+25 %), however, the retroperitoneal adipocytes area was lower (?44 %). Femur mass (+10 %), distance between epiphyses (+4 %) and bone mineral density (+13 %) were higher. The study demonstrates that adequate flaxseed oil content during a lactation diet plays an important role in the development of pups.     

Oil sorbers based on renewable sources and coffee grounds

This work presents useful composites for oil spill cleanup processes. These systems are composed of a polyester matrix loaded with coffee ground powder and maghemite. They were prepared by in situ polymerization. The aliphatic monomers proportion—castor oil and glycerin—was studied with the aim of understanding the effect of feed ratio on the product properties. The materials were studied using several techniques, including Fourier Transform Infrared Spectroscopy, Ultraviolet‐visible Spectrophotometry, and Wide Angle X‐ray Scattering, with magnetic force tests used for the characterization of materials. Density tests showed the presence of coffee grounds causes an important reduction in the density values of composites, improving their flotation. The interaction between composites and petroleum is more than twice that between composites and water. Moreover, for all magnetizable composites, the removal capability was (25.1 ± 1.2) g/g (petroleum/composite), allowing us to state that this is a promising material for use in oil spill cleanup processes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43127.     

Ozonated Mineral Oil: Preparation,Characterization and Evaluation of the Microbicidal Activity

The ozonation of vegetable oils has been studied, since the produced ointments have antibacterial and fungicidal activities. However, the ozonation of mineral oils has not been reported in the literature yet, opening an interesting field for examination. In this work, we have shown the ozonation of a commercial mineral oil (Nujol). The main goal was to produce oils containing free ozone, so that this gas could act as antimicrobial agent. It was found that in Nujol, ozone remains for at least 40 days and in the sample ozonized for 15 h its concentration was 7.5 mg mL^?1. Neat Nujol showed no antimicrobial activity against the tested microorganisms, however, when ozonated it showed antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Escherichia coli.     

Dynamic modeling of the secondary drying stage of freeze drying reveals distinct desorption kinetics for bound water

In freeze drying, the desorption step for reaching a low target moisture content may take a significant fraction of the total process duration. Because the long-term stability of freeze-dried biological products strongly depends on the current moisture content, modeling the desorption process may help safely optimize the secondary drying step. Most published models assume a first-order desorption kinetic, but experimental evidence shows that strongly bound water in the monolayer takes a much longer time to be desorbed than less bound water in multilayer. The proposed model for desorption of freeze-dried lactic acid bacteria preparation accounts for monolayer and multilayer water state in the solid matrix, with very different desorption kinetics. Results showed that the ratio of characteristic desorption times (monolayer/multilayer) was almost 30. Temperature dependence was adequately described by an Arrhenius law in the range of 15 to 40°C. Model parameter identification used simultaneously gravimetric measurements with high time resolution and direct Karl-Fisher titration, from several experiments at different, time-varying temperatures.     

Color stability of denture shade tabs is affected by exposure to daylight and decontamination protocols

The purpose of this study was to investigate the effect of light exposure and decontamination protocols on the color stability of denture shade guide tabs. Fifty tabs for shades 62, 66, and 69 (Biotone IPN, Dentsply Sirona) were submitted to baseline L*a*b* measurements (EasyShade, Vita), separated into 5 experimental groups (n = 10), and subjected to one of the following conditions: G1–distilled water (DW‐H₂O)–control; G2 ?70% alcohol; G3–sodium hypochlorite 1% (NaClO); G4–no light exposure; G5–natural light exposure for 6 months. The experimental conditions were designed to simulate 6 months of clinical use. After the test period, final color measurements were recorded. The mean tristimulus coordinate difference (ΔL*,Δa*,Δb*) and total color difference values () were analyzed using 2‐way ANOVA and the Tukey test, α = .05. G2 (alcohol) produced less (P < .05) color change in shade 69 than G3 (NaClO). G5 (light exposure) affected the color stability for all shades, producing a statistical difference (P < .05) from G4 (no light exposure). It was concluded that natural light changes the color stability of the shade guides and that decontamination with 70% alcohol had the least impact on the color stability of the shade guide tabs.     

Application of microfiltration to egg white depleted in ovomucin

Summary An attempt was made to reduce the microbial load of unpasteurized fresh egg white by using cross-flow microfiltration and a Tetra-Laval bactocatch installation. Cross-flow tangential microfiltration of liquid fresh egg white was not feasible as there was irreversible membrane clogging within a few minutes of operation. As membrane clogging could have been caused by ovomucin, this protein was removed from whole fresh egg white by increasing the salt strength and lowering the pH. Ovomucin-depleted egg white (ODEW) was successfully microfiltered on the same membrane. Compared to fresh egg white, ODEW had lower foaming and viscous properties, and these properties remained unchanged after bactofiltration. The reduction of microbial load was, however, relatively low.     

Room-Temperature Degradation of t-Zr(Pr)O2 in an Aqueous Suspension Revealed by Perturbed Angular Correlations

This paper deals with the phase stability of an aqueous suspension of tetragonal Zr_0.9Pr_0.1O₂ (20 wt%/vol%) at room temperature as a function of the aging time. The suspension is investigated in situ using the highly localized Perturbed Angular Correlations technique. The results indicate that an almost fully reversible degradation process toward monoclinic zirconia takes place through a first-order reaction of rate constant k =0.7 day⁻¹. Two successive diffusion mechanisms are observed that are interpreted as OH⁻ ions' migration in the grain surface and then, as proton defects' diffusion into the bulk.