Polyurethane and PTFE membranes for guided bone regeneration: Histopathological and ultrastructural evaluation

Objective: The purpose of this study was to research a membrane material for use in guided bone regeneration. Study design: In this study, 25 male Wistar rats were used to analyze the biocompatibility and degradation process of biomembranes. The morphological changes in subcutaneous implantations were assessed after 7, 14, 21, 28 and 70 days. The materials were made of polyurethane polymer (AUG) obtained from vegetal oil (Ricinus communis) and polytetrafluoroethylene membrane (PTFE). The surface characteristics of the physical barriers in scanning electronic microscopic (SEM) were also evaluated. Results: In both groups, the initial histological analysis showed moderate inflammatory infiltrate, which was predominantly polymorphonuclear. There was also a presence of edema, which was gradually replaced by granulation tissue, culminating in a fibrous capsule. In the AUG group, some multinucleated giant cells were present in the contact interface, with the space previously occupied by the material. However, membrane degradation was not observed during the period studied. According to the present SEM findings, porosity was not detected in the AUG or PTFE membranes. Conclusion: The researched material is biocompatible and the degradation process is extremely slow or may not even occur at all.

Foam nest in Scinax rizibilis (Amphibia: Anura: Hylidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Foam nest production in the armoured catfish

Foam nest production in Hoplosternum littorale is described in detail. This fish produces foam, while swimming belly-up, by pumping water over the gills and using their pelvic fins to mix water and mucus. The bubbles resulting from this process are added to plant debris carried by the male, which possesses a specialized pectoral fin spine to perform such activity. (C) 1997 the Fisheries Society of the British Isles.

Renal interstitial foam cells are macrophages

Immunohistochemical studies on renal biopsies from eight patients with various types of glomerulonephritis showed that the interstitial foam cells belonged to the monocyte-macrophage lineage. There was a strong association between hypercholesterolaemia and the presence of renal interstitial foam cells.

Electrical properties of a composite of Polyurethane and ferroelectric ceramics

Ferroelectric ceramic particles based on lead titanate zirconate (PZT) were dispersed in a polymer matrix based on castor oil. After the poling process, the pyroelectric activity of this composite was measured using a direct method in which a linear heating rate was applied to the pre-poled samples. The pyroelectric coefficient at 343 K is comparable with that of a PZT-poly(vinylidene fluoride) (PVDF) composite and significantly higher than that of PVDF. © 1998 Kluwer Academic Publishers.

Piezoelectric effect in composite polyurethane-ferroelectric ceramics

Flexible and free-standing films of piezoelectric composites made up of lead zirconate titanate (PZT) ceramic powder dispersed in a castor oil-based polyurethane (PU) matrix were obtained by spin coating and characterized as materials for sensor applications. The piezoelectric coefficients d 31 and d 33 were measured with the usual technique. The piezoelectric charge constant d 33 yields values up to ≤24 pC/N, even at lower PZT content (33 vol%). Some desirable properties like piezoelectricity, flexibility and good mechanical resistance show this new material to be a good alternative for use as sensors and actuators.

Lead zirconate titanate/polyurethane (PZT/PU) composite for acoustic emission sensors

Piezoelectric composite, made from ferroelectric ceramic lead zirconate titanate (PZT) and vegetable based polyurethane (PU) polymer, was doped with a semiconductor filler, graphite. The resulting composite (PZT/C/PU) with 49/1/50- vol. % composition could be poled at lower field and shorter time due to the increased conductivity of the polymer phase following the introduction of graphite. The PZT/C/PU composite showed higher pyroelectric coefficient in comparison with the undoped PZT/PU composite with 50/50-vol. % composition. Also, the PZT/C/PU composite has shown the ability to detect both extensional and flexural modes of simulated acoustic emission (AE) at a distance up to 8.0 m from the source, thus indicating that it may be used for detection of structural damages.

Trophic eggs in the foam nests of Leptodactylus labyrinthicus (Anura, Leptodactylidae): An experimental approach

The South American pepper frog, Leptodactylus labyrinthicus, is a large species that lays eggs in foam nests in holes dug out of the banks of different bodies of water. Recently, it was reported that only 6-10% of eggs are fertilized in foam nests of L. labyrinthicus and the remaining unfertilized eggs are consumed by the tadpoles inside the nest. Here we tested experimentally the influence of the ingestion of trophic eggs on the survivorship and growth of L. labyrinthicus tadpoles. Tadpoles fed on trophic eggs and subsequently fed on dry fish food grew larger than those fed only on dry fish food, and this suggests that the ingestion of trophic eggs is an adaptation to improve tadpole growth. The ingestion of trophic eggs also seems to be important for the maintenance of tadpoles in environments with unpredictable rainfall, as they were able to survive for about 70 days feeding only on these trophic eggs and one tadpole managed to complete metamorphosis feeding on trophic eggs only. Details of the spawning behaviour observed in the field, occurrence of multiple mating, and predation on eggs by terrestrial invertebrates and vertebrates are also reported.

Preparation and characterization of castor oil-based polyurethane/poly(o- methoxyaniline) blend film

Blends made up of castor oil-based polyurethane (PU) and poly(o-methoxyaniline) (POMA) were obtained in the form of films by casting and characterized by FTIR, UV-Vis-NIR spectroscopy, and electrical conductivity measurements. Doping was carried out by immersing the films in 1.0M HCl aqueous solution. Chemical bonds between NCO group of PU and NH group of POMA were observed by means of FTIR spectra. The UV-Vis-NIR spectra indicated that the presence of the PU in the blend does not affect doping and formation of the POMA phase. The electrical conductivity research was in the range of 10-3 S/cm. © 2007 Wiley Periodicals, Inc.

Preparation and characterization of the bacterial cellulose/polyurethane nanocomposites

New nanocomposites based on bacterial cellulose nanofibers (BCN) and polyurethane (PU) prepolymer were prepared and characterized by SEM, FT-IR, XRD, and TG/DTG analyses. An improvement of the interface reaction between the BCN and the PU prepolymer was obtained by a solvent exchange process. FT-IR results showed the main urethane band at 2,270 cm-1 to PU prepolymer; however, in nanocomposites new bands appear as disubstituted urea at 1,650 and 1,550 cm-1. In addition, the observed decrease in the intensity of the hydroxyl band (3,500 cm-1) suggests an interaction between BCN hydroxyls and NCO-free groups. The nanocomposites presented a non-crystalline character, significant thermal stability (up to 230 °C) and low water absorption when compared to pristine BCN. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Glass foam of macroporosity using glass waste and sodium hydroxide as the foaming agent

Glass foams using float glass waste and sodium hydroxide were produced. The influence of the sodium hydroxide amount in the foam formulation was studied. Titanium dioxide was used as a strengthening agent. The variations of temperature, heating rate and sintering time were investigated during the synthesis process. Open porosity was estimated using mercury porosimetry. The morphology of the glass foams was evaluated using scanning electron microscopy, phase formation was studied using X-ray diffraction, and chemical composition was estimated using X-ray fluorescence. As a result, glass foams with macroporosity were obtained. Since the glass foams used glass waste as reactant, the results suggest the development of an alternative route for glass recycling. © 2012 Elsevier Ltd and Techna Group S.r.l.

Development and sensory analysis of shampoo for curly hair

Objective: This study aimed to compare the sensory performance of a shampoo formulation with Polyurethane-14, AMP-acrylates copolymer (PAAC) in relation to control formulation in curly and natural hair tresses. Methods: Curly and natural hair tresses (n = 8) of equal size and weight were pre-treated by washing with a standard shampoo. After the hair tresses were treated with a formulation containing polymer (formulation A) and compared to hair tresses treated with control formulation (Formulation B). Each panelist (n=2) is asked to indicate which tress performs better for each of seven sensory attributes evaluated (quantity and creamy foam, combing, wet touch, frizz formation, curl definition and volume). It was collected images of hair tresses at 0, 1, 2, 4 and 24 hours of washing, comparing the attributes: volume, frizz formation and curl definition. The results were analyzed using table to test of paired assessment, being: SUPERIOR results - 8 and 7 positive evaluations; SIMILAR results - 2 to 6 positive evaluations; INFERIOR results - 1 and 0 positive evaluations. Results: The addition of the PAAC on the shampoo formulation provided definition and modeling of curls, reducing volume and frizz in 24 hours. There was also lower foam formation in the formulation with polymer PAAC. However, it is important to note that this attribute has inversely proportional effect to the creamy foam, since more creamy foam, smaller quantity. Conclusions: It was concluded that the shampoo developed was effective in defining and modeling curl in natural and curly hair.