Color change using HSB color system of dental resin composites immersed in different common Amazon region beverages

The purpose of this study is to evaluate in vitro the color stability of composite resins when exposed to beverages with high coloring contents from the Amazon region. 240 samples from four different composite brands (Natural Look, Z350, 4Seasons and Opallis) of hue A3 were fabricated using an acrylic matrix. The samples were stored in distilled water at 37ºC for 24 hours. The initial color (T0) was registered using a Canon EOS Rebel XTi 10 mp camera, and then the samples were divided into four groups (n=15): G1 (coffee), G2 (açaí juice), G3 (energetic guaraná) and G4 (control - distilled water). The samples were exposed to solutions of DES (6hs) and RE (18hs) and placed in a double boiler under constant agitation, at 37ºC for 30 days. The samples were immersed in the coloring solutions for 15 minutes daily. After 7, 15 and 30 days, new photographic registers were made (T1, T2 and T3). The images were analyzed using Corel PHOTO-PAINT 12 software to identify the colors through the HSB system. The Kruskal-Wallis and t tests (p<0.05) demonstrated significant differences in color (hue, saturation and brightness). The results revealed that none of the tested composites showed color stability when exposed to coloring solutions, and that the Amazon region beverages (açaí juice and energetic guaraná) showed to be less coloring than coffee.

Composite synthetic hydroxyapatite 30%, in two physical states, as dermal filler

The aim of this study was to evaluate the response to the implantation of synthetic hydroxyapatite 30% (HAP-91®) in different physical states as dermal filler. Eighteen New Zealand rabbits were used, distributed randomly into two equal groups and then divided into three groups according to the postoperative period at 8, 21 and 49 days. One mL of HAP-91®, fluid and viscous, was implanted in the subcutaneous tissue, 1 cm proximal to the cranial crest of the right scapula. The thickness of the skin was measured before and after implantation and for the following 15 days. Pain sensitivity assessment was conducted, assigning the following scores: 0 - when the animal allowed the touch of the implant area and expressed no signs of pain; 1 - when the animal allowed the touch, but pain reaction occurred, like increase of the respiratory rate or attempt to escape; 2 - when the animal did not allow the touch to the implanted area. At 8, 21 and 49 days, biopsy of the implanted area was performed. No difference was observed between the thickness of the skin (p>0.05) and all animals received a score 0 for soreness. Histological analysis did not reveal any obvious inflammatory process, showing a predominance of mononuclear cells in samples of eight days and tissue organization around the biomaterial with a tendency to encapsulation. The results indicate that HAP-91®, both viscous and fluid, is biocompatible and suitable for dermal filling.

DOT-ELISA for detection of anti-Cysticercus cellulosae antibodies in human cerebrospinal fluid using a new solid-phase (resin-treated polyester fabrics): preliminary report

A dot enzyme-linked immunosorbent assay (DOT-ELISA) was developed to detect specific antibodies in cerebrospinal fluid (CSF) for human neurocysticercosis immunodiagnosis, with Cysticercus cellulosae antigen dotted on a new solid-phase. This was represented by sheets of a synthetic polyester fabric impregnated with a polymerized resin (N-methylol-acrylamide). A very stable preparation was thus obtained, the antigen being covalently bound by cross-linking with free N-methylol groups on the resin. Since robust, no special care was necessary for handling the solid-phase. The test could be performed at room-temperature. From 30 CSF samples assayed, 14 were positive, from a group of 15 cases of neurocysticercosis, with titers from 1 to 128; 15 other samples, from normals or other neurological diseases, were all negative. Test characteristics seem to indicate it as adequate for epidemiological surveys. A more detailed study on sensitivity, specificity, reproducibility and the use in serum samples is being conducted.

Dot-ELISA-IgM in saliva for the diagnosis of human leptospirosis using polyester fabric-resin as support (Preliminary Report)

In order to improve the diagnosis of human leptospirosis, we standardized the dot-ELISA for the search of specific IgM antibodies in saliva. Saliva and serum samples were collected simultaneously from 20 patients with the icterohemorrhagic form of the disease, from 10 patients with other pathologies and from 5 negative controls. Leptospires of serovars icterohaemorrhagiae, canicola, hebdomadis, brasiliensis and cynopteri grown in EMJH medium and mixed together in equal volumes, were used as antigen at individual protein concentration of 0.2 µg/µl. In the solid phase of the test we used polyester fabric impregnated with N-methylolacrylamide resin. The antigen volume for each test was 1µl, the saliva volume was 8 µl, and the volume of peroxidase-labelled anti-human IgM conjugate was 30 µl. A visual reading was taken after development in freshly prepared chromogen solution. In contrast to the classic nitrocellulose membrane support, the fabric support is easy to obtain and to handle. Saliva can be collected directly onto the support, a fact that facilitates the method and reduces the expenses and risks related to blood processing.

Dot-ELISA for the detection of anti-Cysticercus cellulosae antibodies in cerebrospinal fluid using a new solid phase (resin-treated polyester fabric) and Cysticercus longicollis antigens

A dot-ELISA was developed for the detection of antibodies in CSF in the immunologic diagnosis of human neurocysticercosis, using antigen extracts of the membrane and scolex of Cysticercus cellulosae (M+S-Cc) and, alternately, membrane (M) and vesicular fluid (VF) of Cysticercus longicollis (Cl) covalently bound to a new solid phase consisting of polyester fabric treated with N-methylol-acrylamide resin (dot-RT). The test was performed at room temperature, with reduced incubation times and with no need for special care in the manipulation of the support. The sensitivity rates obtained were 95.1% for antigen Cc and 97.6% for antigen Cl. Specificity was 90.6% when Cc was used, and 96.9% and 100% when M-Cl and VF-Cl were used, respectively. No significant differences in titer were observed between tests carried out with homologous and heterologous antigens. The low cost and easy execution of the dot-RT test using antigen extracts of Cysticercus longicollis indicate the test for use in the immunodiagnosis of human neurocysticercosis.

Larvicidal activity of oil-resin fractions from the Brazilian medicinal plant Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) against Aedes aegypti (Diptera, Culicidae)

Oil-resin fractions from Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) were evaluated for larvicidal activity on third larval instars of Aedes aegypti, in searching for alternative control methods for this mosquito. The bioactive fractions were chemically monitored by thin-layer chromatography, ¹H and 13C nuclear magnetic resonance and mass spectrometry. Bioassays were performed using five repetitions, at a temperature of 28 ± 1°C, relative humidity of 80 ± 5% and light and dark cycles of 12h. Mortality was indicated by darkening of the cephalic capsule after 24h of exposure of the larvae to the solutions. The most active fractions were CRM1-4 (sesquiterpenes) and CRM5-7 (labdane diterpenes), which showed LC50 values of 0.2 and 0.8ppm, respectively.

MANGROVE BARK: A RENEWABLE RESIN SOURCE FOR WOOD ADHESIVES

From four solutions tested to extract tannins from mangrove bark for wood adhesives, hot water is recommended. Hot water extracted 21.4% of formaldehyde-hydrochloric acid reactive polyphenols on oven-dry bark basis.

In vitro cell activating properties of the composite ribosomal vaccine D53

D53 (RibomuntyR) is a composite vaccine made of immunogenic ribosomes from 4 bacterial species (Klebsiella pneumoniae, Haemophilus influenzae, Streptococcus pyogenes and Streptococcus pneumoniae) associated with a membrane proteoglycan from a non encapsulated strain of Klebsiella pneumoniae. D53 is a potent inducer of interleukin-1 production by mouse BALB/c spleen cells as shown by the C3H/HeJ thymocyte co-stimulation assay. Furthermore D53 triggers DNA synthesis by mouse spleen cells and induces the maturation of B lymphocytes into immunoglobulin secreting cells. Polyclonal B cell activation by D53 was readily achieved in the C3H/HeJ strain which is deficient in its response to E. coli lipopolysaccharide. The proliferative response to D53 was abrogated by removal of B cells from the spleen cell suspension, but it was not altered after depletion of T cells or adherent cells. D53 induced polyclonal B cell activation of spleen cells from athymic nude mice and from CBA/N mice. Each component of D53 induced polyclona B cell activation except ribosomes from Streptococcus pneumoniae. Each triggered Interleukin-1 synthesis except ribosomes from Klebsiella penumoniae. These in vitro properties may account for some of the in vivo immunostimulating properties of this composite vaccine.

Handling sticky resin by stingless bees (Hymenoptera, Apidae)

For their nest defense, stingless bees (Meliponini) collect plant resins which they stick on intruders like ants or cleptobiotic robber bees causing their immobilization. The aim of this article is to identify all parts of stingless bee workers contacting these sticky resins. Of special interest are those body parts with anti-adhesive properties to resin, where it can be removed without residues. For that, extensive behavioral observations during foraging flight, handling and application of the resin have been carried out. When handling the resin, all tarsi touch the resin while walking above it. For transportation from plants to the nest during foraging flight, the resin is packed to the corbicula via tarsi and basitarsi of front and middle legs. Once stuck to the resin or after the corbicula had been unloaded, the bee's legs have to be cleaned thoroughly. Only the tips of the mandibles, that form, cut and apply the sticky resin, seem to have at least temporarily resin-rejecting properties.

SEQUENTIAL EXTRACTION OF PHOSPHORUS BY MEHLICH-1 AND ION EXCHANGE RESIN FROM B HORIZONS OF FERRIC AND PERFERRIC LATOSOLS (OXISOLS)

In general, Latosols have low levels of available P, however, the influence of the parent material seems to be decisive in defining the pool and predominant form of P in these soils. This study evaluated P availability by extraction with Mehlich-1 (M-1) and Ion Exchange Resin (IER), from samples of B horizons of Ferric and Perferric Latosols developed from different parent materials. To this end, in addition to the physical and chemical characterization of soils, 10 sequential extractions were performed with M-1 and IER from samples of B horizons (depth between 0.8 and 1.0 m). Total contents of Ca, P, Fe, Al, and Ti were determined after digestion with nitric, hydrofluoric and perchloric acids. The effects of sequential P extractions on Fe oxides were also evaluated from the analyses of dithionite-citrate-bicarbonate and ammonium acid oxalate. The high similarity between contents of P accumulated after sequential extractions with M-1 and IER in soils developed on tuffite indicated a predominance of P-Ca. Higher contents of P after a single IER extraction show greater efficiency in P removal from highly weathered soils, as from the Latosols studied here. The P contents also show the high sensitivity of extractant M-1 in highly buffered soils. Furthermore, a single extraction with extractant M-1 or IER is not sufficient to estimate the amount of labile P in these soils.

Estudo da influência do diluente reativo PGE na cinética de cura de resina epóxi utilizada em compósitos estruturais

Phenil glycidyl ether (PGE), a monofunctional diluent, has been used in epoxy resins formulations in order to increase the toughness of the epoxy molded composite. In a systematic study concerning its influence in the cure kinetics of the epoxy resin, it was used in concentrations of 2,5; 5,0; 10 and 20% in relation to a diglycidyl ether bisphenol-A (DGEBA)/diamino diphenil-sulfone (DDS) base matrix. Dynamic and isothermal scanning analysis were carried out using a differential scanning calorimety (DSC) equipment. For all the concentrations of PGE, a n order kinetics was observed, with n varing between 0,35 -- 0,91 as a function of the increase in the PGE concentration.

Propelente sólido compósito polibutadiênico: I- influência do agente de ligação

In the Brazilian Complete Spacial Mission, the research of Vehicle Satellite Launcher is important. The solid propellant composite used in this vehicle is made with ammonium perchlorate, aluminiun powder and hydroxy terminated polibutadiene resin. In the propellant the bonding agent has a function to promote the interaction between solids and polimeric matrix, improving mechanical properties as stress, strain, aging characteristics and moisture embrittlement. Due its importance in propellant, bonding agent is consider as industrial secret and the literature about it is generic, without greater informations.

Monomer conversion of composite dental resins photoactivated by a halogen lamp and a LED: a FT-Raman spectroscopy study

Eighteen circular blocks of resins cured either by a LED or a halogen lamp (20, 40 and 60 s), had their top (T) and bottom (B) surfaces studied using a FT-Raman spectrometer. Systematic changes in the intensity of the methacrylate C=C stretching mode at 1638 cm-1 as a function of exposure duration were observed. The calculated degree of conversion (DC) ranged from 45.0% (B) to 52.0% (T) and from 49.0% (B) to 55.0% (T) for the LED and halogen lamp, respectively. LED and halogen light produced similar DC values with 40 and 60 s of irradiation.

Eletrodo compósito à base de grafite-araldite®: aplicações didáticas

A composite electrode prepared by mixing a commercial epoxy resin Araldite® and graphite powder is proposed to be used in didactic experiments. The electrode is prepared by the students and applied in simple experiments to demonstrate the effect of the composite composition on the conductivity and the voltammetric response of the resulting electrode, as well as the response in relation to the scan rate dependence on mass transport. The possibility of using the composite electrode in quantitative analysis is also demonstrated.

Efeito de substâncias empregadas para remoção de cobre sobre o teor de compostos secundários da cachaça

High copper content is of great concern among producers of sugar-cane spirits who frequently use filters instead of cleaning the stills. This study compared the efficiency of activated carbon, ion-exchange-polymeric resin, and activated-carbon/iron-oxide magnetic composite for copper reduction without removing excessive organic compounds that are important for the beverage's quality. Resin was the most efficient copper adsorbent, removing fewer organic compounds. The composite also removed copper; however, it also removed large amounts of organic compounds. Activated carbon didn't remove sufficient copper to reduce its concentration to less than 5 g L-1, and it removed large amounts of higher alcohols and esters.