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In dilute aqueous solution unimers of copolymer F127 (E(98)P(67)E(98)) associate to form micelles, and in more concentrated solution micelles pack to form high-modulus gels. Cosolvents are known to affect these processes, and ethanol/water mixtures have been of particular interest. Dynamic light scattering from dilute solutions was used to confirm micellization, but major attention was directed towards the gels. Visual observation of mobility (tube inversion) was used to detect gel formation, oscillatory rheometry to confirm gel formation and provide values of the elastic moduli over a wide temperature range, and small-angle X-ray scattering to determine gel structure. The solvents were limited to 10, 20 and 30 wt.% ethanol/water. Critical concentrations for gel formation were similar for 10 and 20 wt.% ethanol/water but were significantly increased for 30 wt.% ethanol/water, e.g. at T=45 degrees C from c approximately 15 wt.% to c approximately 28 wt.%. The elastic moduli reached maximum values at T approximately 50 degrees C: e.g. G' approximately 25 kPa for 25 wt.% F127 in 10 and 20 wt.% ethanol/water and a similar value for 30 wt.% F127 in 30 wt.% ethanol/water. Hard gels of 30 and 35 wt.% F127 in ethanol/water at 25 and 40 degrees C had the body-centered cubic (bcc) structure.

Cashew nut-shell liquid and the contained anacardic acids (AAs) have been shown to possess antioxidant, lipoxygenase inhibitory, anti-Helicobacter pylori and antitumor properties. Despite these known effects, hitherto there were no published reports on their likely gastroprotective effects. The present study was designed to verify whether AAs afford gastroprotection against the ethanol-induced gastric damage and to examine the underlying mechanism(s). Gastric damage was induced by intragastric administration of 0.2mL of ethanol (96%). Mice in groups were pretreated orally with AAs (10, 30 and 100mg/kg), misoprostol (50 microg/kg), or vehicle (2% Tween 80 in saline, 10mL/kg), 45min before ethanol administration. They were sacrificed 30min later, the stomachs excised, and the mucosal lesion area (mm(2)) measured by planimetry. Gastroprotection was assessed in relation to inhibition of gastric lesion area. To study the gastroprotective mechanism(s), its relations to capsaicin-sensitive fibers, endogenous prostaglandins, nitric oxide and ATP-sensitive potassium channels were analysed. Treatments effects on ethanol-associated oxidative stress markers GSH, MDA, catalase, SOD, and total nitrate/nitrite levels as an index of NO were measured in gastric tissue. Besides, the effects of AAs on gastric secretory volume and total acidity were analysed in 4-h pylorus-ligated rat. AAs afforded a dose-related gastroprotection against the ethanol damage and further prevented the ethanol-induced changes in the levels of GSH, MDA, catalase, SOD and nitrate/nitrite. However, they failed to modify the gastric secretion or the total acidity. It was observed that the gastroprotection by AAs was greatly reduced in animals pretreated with capsazepine, indomethacin, l-NAME or glibenclamide. These results suggest that AAs afford gastroprotection principally through an antioxidant mechanism. Other complementary mechanisms include the activation of capsaicin-sensitive gastric afferents, stimulation of endogenous prostaglandins and nitric oxide, and opening of K(+)(ATP) channels. These combined effects are likely to be accompanied by an increase in gastric microcirculation.

Microspheres of low degree of esterification (DE) pectin with calcium and the same sphere coated with chitosan (PCaC) were prepared. The spheres have diameters in the range 650–680 μm. The layer of chitosan is about of 5–15 μm thick. To obtain firm and stable PCaC beads, chitosan was reacetylated. Two different degrees of acetylation, giving PCaC50 and PCaC80 were adopted. The beads were characterized by FTIR, SEM and swelling measurements. Mangiferin was loaded in PCaC reacetylated in two different ways: by addition in pectin solution ( M p ) and by addition in CaCl 2 solution ( M c ). The yield in producing the beads, the efficiency in encapsulation and the content of mangiferin in beads were determined. A swelling kinetics study was done in simulated gastric fluid (SGF, pH 1.2) and in simulated intestine fluid (SIF, pH 7.4). The release of mangiferin from the beads was performed in SGF followed by the release in SIF. Based on the yield and efficiency in encapsulation the best bead was found to be PCaC50- M p . The highest release (7.8 mg of mangiferin/g of bead) was achieved by the PCaC50- M c . For all beads more bioactive was released in SGF than in SIF.

Aedes aegypti is the major vector of 1 of the most concerning arboviruses of the world, the dengue fever. The only effective way of reducing the incidence of dengue fever is to control the vector mosquito, mainly by application of insecticides to its breeding places. This study was aimed at assessing the insecticidal activity of sodium anacardate, isolated from Brazilian cashew nut shell liquid (CNSL), against the eggs, 3rd instars or pupae of Ae. aegypti. In addition, the acute toxicity of sodium anacardate to mice was also investigated. Sodium anacardate showed toxicity against Ae. aegypti eggs (median effective concentration [EC50] = 162.93 +/- 29.93 microg/ml), larvae (median lethal concentration [LC50] = 55.47 +/- 3.0 microg/ml) and pupae (LC50 = 369.78 - 52.30 microg/ml). On the other hand, even at high dose (0.3 g/kg body weight), this compound did not cause any adverse effects on mice, suggesting that this compound is safe to mammals. Therefore, sodium anacardate may be a viable low-cost alternative to help combat Ae. aegypti.

The properties of the jalap starch (Operculina tuberosa Meisn.) were investigated and compared with other already known starches (potato and wheat starch). The jalap starch presented peak viscosity lower than the one from potato but higher than wheat starch, while the stability during the cooling down was higher than potato and wheat starch. The jalap starch presented X-ray pattern of type-A, which is typical of those from wheat starch. The rheological and physico-chemical characteristics presented by this source of starch were intermediate between those from wheat and potato, which makes it a promising commercial source to be explored, mainly in areas with food scantiness as in the Brazilian Northeast.

Gel diagrams based on tube inversion and oscillatory rheometry are reported for Pluronic copolymers F127 (E(98)P(67)E(98)) and P123 (E(21)P(67)E(21)) in mixtures with anionic surfactant sodium dodecyl sulfate (SDS). Total concentrations (c, SDS+copolymer) were as high as 50 wt % with mole ratios SDS/copolymer (mr) in the ranges 1-5 (F127) and 1-7 (P123). Temperatures were as high as 90 degrees C. Determination of the temperature dependences of the dynamic moduli served to confirm the gel boundaries from tube inversion and to reveal the high elastic moduli of the gels, e.g., compared at comparable positions in the gel phase, a 50 wt % SDS/P123 with mr = 7 had G' three times that of a corresponding gel of P123 alone. Small-angle X-ray scattering (SAXS) was used to show that the structures of all the SDS/F127 gels were bcc and that the structures of the SDS/P123 gels with mr = 1 were either fcc (c = 30 wt %) or hex (c = 40 wt %). Assignment of structures to SDS/P123 gels with values of mr in the range 3-7 was more difficult, as high-order scattering peaks could be very weak, and at the higher values of c and mr, the SAXS peaks included multiple reflections.

The use of natural substances in health applications may be hampered by the difficulties in establishing the mechanisms of action, especially at molecular-level. The protein-polysaccharide complex extracted from the mushroom Agaricus blazei Murill, referred to as CAb, has been considered for treating various diseases with probable interaction with cell membranes. In this study, we investigate the interaction between CAb and a cell membrane model represented by a Langmuir monolayer of dimyristoyl phosphatidic acid (DMPA). CAb affects the structural properties of DMPA monolayers causing expansion and increasing compressibility. In addition, interaction with DMPA polar heads led to neutralization of the electrical double layer, yielding a zero surface potential at large areas per molecule. CAb remained at the interface even at high surface pressures, which allowed transfer of Langmuir-Blodgett (LB) films onto solid supports with the CAb-DMPA mixture. The mass transferred, according to quartz crystal microbalance (QCM) measurements, increased linearly with the number of deposited layers. With UV-vis absorption, fluorescence and FTIR spectroscopies, we confirmed that the LB films contain polysaccharides, proteins and DMPA. Therefore, the CAb biological action must be attributed not only to polysaccharides but also to proteins in the complex.

The dependence of log(cmc) on hydrophobic block length n was examined for EmBn copolymers (E = oxyethylene, B = oxybutylene, subscripts denote number-average block lengths in repeat units)with n in the range 30-76. Combination with published data for EmBn diblock copolymers with shorter E-blocks shows two changes of slope in the log(cmc)-n plot corresponding to the onset of unimolecular micelle formation at n approximate to 12 and completion of this process at n approximate to 30. The results are discussed with reference to published data for EmLn and EmCLn (L from D,L-lactide; CL from epsilon-caprolactone) copolymers, which show similar behaviour. (C) 2008 Elsevier B.V. All rights reserved.

The micellization in dilute aqueous solution of Pluronic copolymers P123 (E21P67E21) and F127 (E98P67E98) and mixtures of the two was investigated using static and dynamic light scattering. Gelation of concentrated solutions of the two copolymers and their mixtures was studied using tube inversion and oscillatory rheometry. The two copolymers comicellized to give micelles with narrow size distributions. Clouding temperatures and critical micelle temperatures decreased as the proportion of P123 in the mixture was increased. Micelle association numbers of the mixed micelles lay between the values found for micelles of P123 and F127 alone, whereas micelle radii passed through maximum values in the range 0-50 wt % P123. As judged by the ratio of the thermodynamic to the hydrodynamic radius, the micelle interaction potential changes gradually from soft to hard as the proportion of P123 in the mixture is increased. Regions of cubic and hexagonal (birefringent) gel were defined for concentrated solutions. The high-temperature boundary of the 30 wt % cubic gel decreased monotonically from 90 to 43 degrees C as the proportion of P123 in the mixture was increased from 0 to 100 wt %, whereas the low-temperature boundary was essentially constant at 15 +/- 3 degrees C. Increasing the proportion of P123 in the mixture at 25 degrees C increased the concentration at which the cubic gel was first formed and decreased the concentration at which the hexagonal gel was first formed.

Raman scattering investigations of surfactant solubilized SWCNTs under hydrostatic pressure were performed. The wave number dependence on pressure for the tangential bands was observed to be discontinuous at 2 GPa, with change of slope for higher pressures. This change coincides with the calculated critical pressure for collapse of the tubes. Therefore, it could be considered as indicative of deformation of the tube along the radial direction.

A novel superabsorbent hydrogel (SH) composite based on a poly(acrylamide-co-acrylate) matrix filled with nontronite (NONT), a Fe(III)-rich member of the smectite group of clay minerals, is described in this manuscript. A variety of techniques, including FTIR, XRD, TGA, and SEM/EDX, were utilized to characterize this original composite. Experimental data confirmed the SH composite formation and suggested NONT was completely dispersed in the polymeric matrix. Additionally, NONT improved the water uptake capacity of the final material, which exhibited fast absorption, low sensitivity to the presence of salt, high water retention and a pH sensitive properties. These preliminary data showed that the original SH composite prepared here possesses highly attractive properties for applications in areas such as the agriculture field, particularly as a soil conditioner.

Biolubricants are defined like long-chain esters that have lubricant properties and can be obtained from animal or vegetal resources. In this work, the obtainment of the biolubricant by the transesterification of the sesame methyl and ethyl biodiesel in the presence of polyalcohol (trimethylolpropane—TMP) is reported. To conduct the experiment, a distillation-fractioned system was adapted. The reaction conditions were: 3/1 biodiesel/TMP molar ratio, 2 wt% of sodium methoxide catalyst, and reaction temperature and time 110 °C and 6 h respectively. Physicochemical properties like acid value, iodine value, kinematic viscosity at 40 °C, and density at 20 °C were determined. The products were characterized by infrared spectroscopy and 1H and 13C nuclear magnetic resonance (NMR). The thermogravimetric analysis (TGA) of the bioproducts was realized and the main thermal events were evaluated.

The non-commercial copolymers E45S8, E45S17 and their mixtures with Pluronic® P123 (E21P67E21) were studied as carriers of the model drug griseofulvin. Critical micelle concentration (cmc) (dye solubilisation method), drug solubilisation capacity (Scp and Sh) determined by ultraviolet-visible (UV-Vis) spectroscopy and 1H nuclear magnetic resonance (1H NMR) and cytotoxicity (LDH activity in human neutrophils) were studied. E45S17 1.0 wt.% dispersions presented colloidal aggregates limiting its Scp in comparison to E45S8, but in 0.1 wt.% solutions this phenomenon seemed to be absent and E45S17 presented a higher Scp. The mixtures that showed the best Scp results contained 50% of P123 and presented low cmc. An evaluation of literature data suggested a minimum Em content of 62% in EmSn copolymers below which the increase of Sn length does not lead to an increase of Sh. The results suggested no toxicity of the copolymers on human neutrophils, supporting the use of P123 and poly(styrene oxide) containing copolymers as drug carriers.

In this study, the spray drying technique was used to prepare L-ascorbic acid (AA) microparticles encapsulated with galactomannan-an extract from the seeds of the Delonix regia species. The physico-chemical characteristics, antioxidant activity, and encapsulation efficiency of the AA microparticles were evaluated and characterized using thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The free-radical scavenging activity of the AA microparticles was determined at different environmental conditions using DPPH (1,1-diphenyl-2-picryl-hydrazyl). X-ray diffraction measurements demonstrated a loss of crystallinity in AA after the encapsulation process, and a DSC scan also showed the loss of the compound's melting peak. Thermogravimetric analysis showed small differences in the thermal stability of galactomannan before and after the incorporation of AA. The mean diameters of the obtained spherical microspheres were in the range of 1.39 ± 0.77 µm. The encapsulation efficiency of AA microparticles in different environmental conditions varied from 95.40 to 97.92, and the antioxidant activity showed values ranging from 0.487 to 0.550 mg mL-1.

Small-angle X-ray scattering was used to characterise aqueous micellar gels of triblock copolymers E137S18E137, E82S9E82, E76S5E76, E62P39E62, and of two mixtures: E137S18E137 and E62P39E62 (Mix 1) and E82S9E82 and E62P39E62 (Mix 2), each 50/50 wt%. E = oxyethylene, CH2CH2O; S = oxyphenylethylene, OCH2CH(C6H5); and P = oxypropylene, OCH2CH(CH3). Within the concentration and temperature ranges investigated (30–40 wt% copolymer, 20–80 °C), spherical micelles of copolymers E137S18E137, E82S9E82 and E62P39E62 packed into body-centred cubic (BCC) structures. Gels of E76S5E76 were stable only at high concentrations and low temperatures, and a 70 wt% copolymer solution at T = 30 °C formed a hexagonal gel consistent with cylindrical micelles. It is likely that the mixed copolymers would form two distributions of micelles, and more complex structures were expected. However, gels of Mix 2 had well-ordered BCC structures, while the less ordered gels of Mix 1 were also best characterised as BCC. Copyright © 2006 Society of Chemical Industry

Micellar solutions of EmPnEm copolymers may be mobile at ambient temperature and form hard gels on warming to body temperature, whereas micellar solutions of EmSnEm copolymers do not show this effect (E denotes oxyethylene, P oxypropylene and S oxyphenylethylene, and subscripts m and n denote chain lengths). The aim of this study was to combine the desirable gelation characteristics of solutions of the EmPnEm copolymers with the greater solubilising capacities of solutions of the EmSnEm copolymers. Accordingly, the gelation characteristics in aqueous solution of binary mixtures of the triblock copolymer E62P39E62 (Pluronic F87) with E137S18E137, E82S9E82 or E76S5E76 were investigated by rheological techniques. We have shown that 50/50 wt.% mixtures of E62P39E62 with either E137S18E137 or E82S9E82 at a total copolymer concentration of approximately 30 wt.% are fluids of low viscosity at temperature below 22-25 degrees C and gels of high elastic modulus at body temperature.The mixed systems have potential as vehicles for the controlled delivery of solubilised drug from gels formed in situ following subcutaneous injection of a low viscosity aqueous solution.

An efficient route has been developed to isolate water soluble polysaccharides from Agaricus blazei Murill mushroom of Brazilian origin. Using different temperatures: 10, 60 and 100 °C, and precipitation with ethanol, a number of precipitates were extracted which were isolated, purified and fractionated for characterization. The molar mass distribution for the precipitates and fractions from the extraction at 100 °C were determined by GPC. Analysis of the FTIR, 1H NMR and 13C NMR spectra showed a pattern characteristic of glucan–protein complex.

The solubilisation capacities of micellar solutions of diblock and triblock copolymers composed of hydrophilic poly(ethylene oxide) and hydrophobic poly(styrene oxide) have been compared using the poorly water-soluble drug griseofulvin as a model solubilisate. Our results showed an increase of solubilisation capacity (expressed as mg griseofulvin per gram of hydrophobic block) with temperature and, for spherical micelles, with core volume before reaching limiting values. A change of micelle shape from spherical to cylindrical (or worm-like) resulting from an increase in micelle aggregation number was accompanied by a further enhancement of solubilisation capacity. Comparison with the solubilisation of the same drug in micellar solutions of block copolymers of poly(ethylene oxide) and poly(1,2-butylene oxide) showed that the solubilisation capacity of a poly(styrene oxide) block was approximately four times that of a poly(1,2-butylene oxide) block for spherical micelles. Solubilisation capacity at 25 degrees C was approximately doubled when griseofulvin was incorporated into a copolymer melt and micelles initially formed from the drug-loaded melt at 65 degrees C rather than by loading the drug into pre-micellised solution at 25 degrees C in the usual manner.

The fermented cassava starch (polvilho azedo) in 1:5 starch to water ratio (w/v), was subject to annealing treatment at 50 °C for 72, 96, 144 and 240 h. The annealing treatment changed the internal structure of polvilho azedo when the time was increased. Peak viscosities decreased significantly, denoting that there was a decreasing in leaching of amylose from the granules. The pasting temperature was increased, while hold, final viscosities, and breakdown were reduced showing an enlargement on the stability of the paste. The swelling power and the solubilities underwent reductions in all temperatures. The DSC data showed that there was an increased on To, Tp, Tc and ΔH in all samples annealed. The X-ray diffraction pattern did not change but crystallinity increased (all samples annealed), denoting increase in organization of double helical of amylopectin. The polvilho azedo samples submitted to annealing treatment acquired some characteristics of cereal starches (waxy starches).

Unfermented cassava starch (polvilho doce) was subject to annealing treatment at 50°C for 24, 48, 96, 120, 168 and 192 h, in 1:5 starch to water ratio. The annealing treatment changed the internal structure of polvilho doce at increasing treatment time. Peak viscosities decreased significantly, denoting that there was a decrease in leaching of amylose from the granules. The pasting temperatures were increased, setback and breakdown were reduced while hold and final viscosities increased, showing an improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55°C was zero after 120 h of treatment. The DSC data for T o , T p , T c and AH increased and the gelatinization range was narrowed. The X-ray diffractograms changed from C A to A pattern (samples annealed for 48, 96,120,168 and 192 h), denoting an increase in organization of double helices of amylopectin. Annealing imparts to the samples some waxy starches characteristics which can be very useful in the food industry.

Unstretched films of natural rubber (NR) from Hevea brasiliensis were exposed to ozone flow of 15 ml min−1 from 4 to 300 min. The efficiency of reaction was determined by ozone consumption of NR films. Plots of reacted ozone mass versus film thickness show that the ozone penetration and the ozone reaction progressed into deeper layers (170 µm) than described in the literature (∼0.5 µm). The previous proposed model based on viscometry measurements was corroborated by ozone consumption results. The effect of thickness on the O3/NR stoichiometric ratio indicated that the diffusion process that controls the ozonation in unstretched film does not consist of the boundary progression behind which all reactive sites have been saturated. Ozonation in unstretched rubber film, while being less efficient than ozonolysis in solution, does have a reaction efficiency of the same order of magnitude. NMR spectroscopy was used to characterise the products formed by ozonation. Copyright © 2004 Society of Chemical Industry

Multilayer membranes were prepared by alternating adsorption of a cationic polyelectrolyte, chitosan, and an anionic polyelectrolyte, poly(4-styrene sulfonate), onto zeolite A films formed on porou...

The preparation of water-based ionomer dispersions by the post-polymerisation addition of zirconium species is described. The post-polymerisation addition studies were carried out on two series of polymer latices, poly(n-butylacrylate-stat-butylmethacrylate-start-acrylic acid) and poly(n-butylmethacrylate-stat-butylacrylate-start-acrylic acid) both prepared by semi-continuous emulsion polymerisation. A method has been established by which zirconium (in the form of ammonium zirconium carbonate (AZC)) can be successfully introduced to the latices without effecting the colloidal stability. This was confirmed by using both dynamic light scattering and rheology techniques.

We studied the physicochemical, piezoelectric and dielectric properties of collagen–natural rubber (NR) films. The piezoelectric strain tensor element d14, and the dielectric permittivity e11 were obtained for the collagen–NR blends. Resonance measurement of the piezoelectric strain constant d14 of collagen gives 0.057 pC/N. It was observed that for the addition of 10% of NR we have a decrease of the piezoelectricity to 0.042 pC/N. Our results also show that the presence of NR contributes to the increase of the thermal stability of the collagen films. The denaturation temperatures of collagen increases with the presence of NR. For the blend with 25% of NR (S2––Col75bn25), one has the highest denaturation temperature (109.6 °C). We also believe that the presence of NR lead to the decrease of the organization of the microscopic structure of the films, which results in the decrease of the piezoelectricity.

Nine triblock copolymers of ethylene oxide and styrene oxide (type EmSnEm, E = oxyethylene, S = oxyphenylethylene, n and m = number-average block lengths) were prepared by sequential oxyanionic polymerization. Surface tensiometry was used to determine critical micelle concentrations (cmc's) and standard enthalpies of micellization, and isothermal titration calorimetry was used to confirm the enthalpy of micellization. Light scattering was used to determine micellar association numbers and hydrodynamic radii. Phase diagrams defining regions of hard and soft gel were determined by tube inversion and Couette rheometry. Comparison is made with reported results for diblock copolymers of ethylene oxide and styrene oxide and, so far as possible, with results for triblock copolymers of ethylene oxide and styrene. Compilation of values of the cmc for three series of triblock copoly(oxyalkylene)s, EmSnEm, EmBnEm (B = oxybutylene), and EmPnEm (P = oxypropylene), reveals a discontinuity in the block length dependence of log(cmc) at S6 and B12.

Copolymer E11B8 [E denotes OCH2CH2, B denotes OCH2CH(C2H5), and the subscripts denote number-average chain lengths] was prepared by sequential oxyanionic polymerization and characterized by GPC (for distribution width) and NMR spectroscopy (for absolute composition and chain length). It was studied as prepared with hydroxyl groups terminating the B-blocks (E11B8H) and after methylation (E11B8M). Clouding temperatures were determined over a wide concentration range, and critical micelle concentrations were determined by dye solubilization. Dynamic and static light scattering were used to characterize the micelles and demonstrate the formation of compact micelles at low temperatures which change to large (probably wormlike) micelles on heating the solution to temperatures within 10 °C of the clouding boundary. The solubilization of griseofulvin (a drug with poor water solubility) was determined over a range of temperature, and the effect of micelle size on this property is discussed.

1H wideline and 13C magic-angle spinning NMR have been used to study the morphology and dynamics of latex-cast and solution-cast film blends of natural rubber (NR) and a polyurethane (PU) based on poly(ϵ-caprolactone) diol and isophorone di-isocyanate. 1H T1 and T1ρ relaxation times have been measured, and the extent of interpenetration of the NR and PU constituents has been monitored using the Goldman–Shen technique. The NMR spectra and relaxation properties indicated that the NR and PI constituents largely occupy separated domains on a distance scale of >10 nm. The Goldman–Shen experiments indicated that there was slightly greater contact between NR and PU in the solution-cast samples than in the latex-cast. The tensile properties of the films have been measured. The tensile strength and initial Young's modulus pass through a maximum at a PU content of about 50 wt%. © 2002 Society of Chemical Industry

The solubilisation of griseofulvin in 1 wt% aqueous micellar solutions of Pluronic F127 at 37 °C has been modified by adding polyethylene glycol PEG 35000 or poly(vinylpyrrolidone) PVP K30. The solubilisation capacity expressed in terms of unit weight of F127 is increased by the addition of 0.5 wt% PEG 35000 to a value approaching double that of a 2.5 wt% solution of F127 alone, but there is no advantage in adding 0.5 wt% PVP K30.

In this work, chitosan/mangiferin particles (CMP) were prepared by spray-drying technique and characterized by SEM, DLS, FTIR, HPLC–UV and adsorption studies to investigate a possible application as a preventive material in cases of human and animal contamination with Cr(VI). CMP presented sizes ranging from nano to micrometers. Chitosan and mangiferin (MA) presence in the powder was confirmed by FTIR and MA quantification (136 μg/mg) was performed using a calibration curve prepared by HPLC–UV. Adsorption capacity of Cr(VI) onto CMP was compared with chitosan and investigated in a batch system by considering the effects of various parameters like contact time, initial concentration of adsorbent and pH. Cr(VI) removal is pH dependent and it was found to be maximum at pH 5.0. The results showed that CMP has a potential application as a preventive material in cases of human or animal contamination with Cr(VI).

Elaine Cristina Pereira, Evânia Altina Teixeira De Figueiredo, Nagila Maria Pontes Silva Ricardo, Denilton Garcia Santos, Ana Carolina Barbosa Ribeiro, Arcelina Pacheco Cunha. Atividade Antimicrobiana da Pectina do Noni (Morinda Citrifolia L.) Contra Bacterias de Origem Alimentar.. In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-311 Atividade Antimicrobiana da Pectina do Noni (Morinda Citrifolia L.) Contra Bacterias de Origem Alimentar.

Solid-state NMR spectroscopy and Fourier transform IR (FTIR) spectroscopy have been used to study the degradation of cellulose in the form of transformer insulating paper and Whatman filter paper in air at temperatures from 200°C to 550°C for 1 h with and without 0.01 wt.% NaCl, ZnCl 2 and CuCl 2 . The NMR studies included 1 H wide line measurements of the spin-lattice relaxation time ( T 1 ) and spin-lattice relaxation time in the rotating frame ( T 1ρ ), and 13 C magic-angle spinning experiments. The 1 H spectra and relaxation times indicated the presence of absorbed water and oxygen in the papers. On degradation, the 1 H intensity and line width decreased, indicating the loss of hydrogen nuclei, and the 1 H relaxation times decreased due to the formation of paramagnetic species. The 13 C-NMR spectra and FTIR spectra indicated the formation of aromatic structures on degradation above 250°C, the conversion being essentially complete at 450°C. The presence of the salts had little or no effect on the rate or mechanism of degradation.

Unstretched films of natural rubber from Hevea brasiliensis were exposed to ozone flow of 5 and 15 mL/min for 4 to 60 min. The effect of reaction time and the film thickness was studied by viscometry and gel permeation chromatography (GPC). For film thicknesses, in the range of 40 to 350 µm, an initial increase in the intrinsic viscosity, [η], was observed within 8 min of reaction, followed by a decrease for longer times. For thin films, only a decrease in the [η] was observed. The viscosity increase, followed by its decrease, suggests the formation of crosslinking and chain cleavage, respectively, both expected by Criegge mechanism. The plot of [η] versus film thickness and the Chromatographic analysis, related either to 8 or to 60 min of reaction, show that the ozone penetration and the ozone reaction progresses into deeper layers than those previously described in the literature (∼0.5 µm), in this case, 170 and 250 µm, respectively. One model was proposed to explain the viscosity, GPC and attenuated total reflection (ATR) results.

Manihot glaziovii rubber was dissolved in purified chloroform and coagulated with methanol. An oily like material (ACM) remaining from the coagulation process was isolated and submitted to column chromatography over silica gel yielding several fractions. The components of the major fraction, denoted collectively as F-GH, were isolated and characterised by FTIR, 1H and 13C NMR spectroscopies and GC/MS as sitosterol, stigmasterol and a mixture of palmitic and oleic acid. The effect of ACM itself and the components of F-GH on the thermal oxidation of rubber film at 140 °C was verified by the use of FTIR. The induction time and the rate constant were determined.

The thermal degradation of cellulose in the form of Kraft insulating paper has been studied in air for up to 140 h and in transformer oil for up to 3500 h in the temperature range 60–120 °C using measurements of the degree of polymerization (DP) and (in oil) analysis of furanic degradation products. Degradation was faster in air than in oil. The DP decreased from the original value of 1.2 × 103 to a limiting value in the range of 300–900 depending on temperature and degradation conditions. The variation of the DP with degradation time was consistent with two mechanisms, one in which the first-order rate constant decreased exponentially with time, and another in which only a limited number of chain bonds were scissionable. The degradation rate was first order in scissionable bonds. The major furanic degradation products were 2-furaldehyde, 5-hydroxymethyl-2-furaldehyde and furfuryl alcohol. Their concentrations continually increased over the timescale of the experiments. © 2001 Society of Chemical Industry

The influence of hydrophobic-block length on solubilisation capacity was examined for micelles of E(m)B(n) copolymers (E=oxyethylene, B=oxybutylene, subscripts denote number-average block lengths in repeat units) with B-block lengths in the range of 30-76 and with E-blocks of sufficient length to ensure the formation of spherical micelles. Griseofulvin was used as a model poorly-water-soluble drug known to be almost exclusively solubilised in the micellar core. Combination of solubilisation data with those of a previous study has shown that the amount of drug solubilised per gram of hydrophobe is essentially independent of B-block length when this exceeds about 15 B units, suggesting that core size is not a major influence on solubilisation.

Water-based ionomer dispersions were formed by post-polymerization addition of zirconium species to polymer latices prepared from butyl methacrylate (BMA), butyl acrylate (BA) and acrylic acid (AA) by semicontinuous emulsion polymerization. The mole fraction of AA in the latex particles was kept at 10 mole% in all cases whereas the ratio of BA to BMA was varied. A method was established which allowed zirconium in the form of ammonium zirconium carbonate (AZC) to be successfully introduced into the latices without affecting their colloidal stability. Dynamic light scattering was used to determine average particle size in diluted latices. The structure and properties of cast ionomer films were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile strength and swelling measurements. Fourier transform infrared spectroscopy (FTIR) was used to investigate the nature of the carboxylate bonding.

The antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from Brazilian semiarid region were investigated. The extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. Six extracts presented activity against the Gram (−) organismSalmonella choleraesuisand the Gram (+) organismsStaphylococcus aureusandBacillus subtilis. The MIC values ranged from 4.96 to 37.32 mg/mL. TheTriplaris gardnerianaextract presented activity against the three species, with MIC values 18.8, 13.76, and 11.15 mg/mL, respectively. Five extracts presented antioxidant activity, with EC50values ranging from 69.73 μg/mL (T. gardneriana) to 487.51 μg/mL (Licania rigida). For the anticholinesterase activity, eleven extracts were capable of inhibiting the enzyme activity. From those,T. gardneriana,Parkia platycephalaandConnarus detersuspresented the best activities, with inhibition values of 76.7, 71.5, and 91.9%, respectively. The extracts that presented antimicrobial activity were tested for hemolytic assay against human A, B, and O blood types and rabbit blood. From those, only theMyracrodruon urundeuvaextract presented activity (about 20% of hemolysis at the lowest tested concentration, 1.9 µg/mL). Infrared spectroscopy of six representative extracts attested the presence of tannins, polyphenols, and flavonoids, which was confirmed by a qualitative phytochemical assay.

This paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series of pharmacological properties: antioxidant, cytotoxic, analgesic, anti-inflammatory, antitumor and antiplatelet. Onco A was associated with magnetite nanoparticles in order to obtain magnetic properties. The components of MO-20 were characterized by XRD, FTIR, TGA, TEM and Magnetization curves. The MO-20 presented a size of about 30 nm and globular morphology. In addition, drug releasing experiments were performed, where it was observed the presence of the anomalous transport. The results found in this work showed the potential of onco A for future applications of the MO-20 as a new magnetic drug release nanosystem for cancer treatment.

A water soluble polysaccharide and its selective precipitated fractions (F1, F2, and F3) were isolated from hot water extract of fruiting bodies of Agaricus blazei Murril known as Agaricus brasiliensis to evaluate the analgesic activity of the materials in Swiss mice. The isolated material and its fractions were characterized by two-dimensional COSY and HMQC spectra as β-(1→6)-α-(1→4)-glucan-bound-protein polysaccharide constituted mainly by β-(1→6) glucan. The glucan-protein polysaccharide and its fractions were analyzed in relation to the protein, carbohydrate, and mineral elements contents. The analysis of the glucan-protein complex revealed a total carbohydrate content of 36.95% and protein conjugated content of 17.24%. The mineral elements found in larger proportion were K, Na, Ca, P, and Zn. The analgesic activity bioassay of the β-(1→6)-α-(1→4)-glucan bound-protein polysaccharide and its fractions in Swiss mice indicated a significant effect.

We report on the synthesis of non-ionic surfactants via the Koenigs-Knorr reaction with chemical structures GOR and GOPOG, where GO(H) is glucose, R is n-decyl or n-dodecyl, and P is polyoxypropylene or polycaprolactone. Surface properties were studied using a Cenco-du-Nouy tensiometer. Light and transmission electron microscopy were used to investigate the phase behavior of the surfactants over a range of concentrations. AOR surfactants, where A is the product of amylose degradation and R is decyl, were synthesized by an alcohol exchange procedure.

Rice husk ash (RHA), an industrial waste, was incorporated in the preparation of high performance chitosan (CTS) and poly(acrylic acid) (PAA) based superabsorbent hydrogel. Hydrogels filled with RHA previously calcinated at 900 °C (RHA900) showed better water uptake (225 gwater/gabsorbent) than those with husk calcinated at 400 °C (RHA400) (198 gwater/gabsorbent) due to the higher purity and crystallinity, at same composition. The hydrogel composite at 5 wt-% of RHA900 showed the best water uptake (255 gwater/gabsorbent). A clear reduction in swelling degree is observed by increasing the amount of crosslinker from 1 to 3 wt-% due to the increase in the crosslinking density forming more rigid hydrogels. On the other hand, an increase in the initiator amount from 1 to 3 wt-% increased the water uptake due to the formation of greater numbers of active sites increasing the number of PAA chains grafted into CTS backbone. Furthermore, the hydrogel composites presented responsive behavior in relation to both pH and sat solution. The data shows it is possible to obtain high performance materials by incorporating an industrial waste, rice husk ash, in the preparation of hydrogel composites.

In this work, it was investigated the effect of organically modified vermiculite and montmorillonite (OVMT and OMMT, respectively) in asphalt binders (AB) modified by SBS (styrene-butadiene-styrene). The physical and rheological properties were performed for AB, 4.0% SBS MB and nanocomposite AB modified by 2.5% SBS with 2.5% of organoclays. The modified binders (MB) result in the enhancement of complex modulus (G*) and reduction of phase angle (d), which means greater resistance to permanent deformation. The viscosity, penetration and thermal susceptibility were appropriate. The black diagrams show that the effect of nanoclays OVMT and OMMT was similar to the effect of Cloisite®. The rheological properties of the nanocomposite were comparable to the 4.0% SBS MB, identifying a cost reduction due to the potential of replacing polymer with clay. The presence of OVMT improved the storage stability of SBS MB, an important result, as the phase separation is a major obstacle to the use of SBS in paving. Neste trabalho, investigou-se o efeito da vermiculita e montmorilonita organicamente modificadas (OVMT e OMMT, respectivamente) em ligante asfáltico (AB) modificado por SBS (butadieno-estireno-butadieno). As propriedades físicas e reológicas foram avaliadas para AB, 4,0% SBS MB e nanocompósitos AB modificados por 2,5% SBS com 2,5% de organoargilas. Os ligantes modificados (MB) resultaram no aumento do módulo complexo (G*) e na redução do ângulo de fase (d), o que significa maior resistência destes à deformação permanente. A viscosidade, penetração e suscetibilidade térmica foram adequadas. Nos diagramas black, observou-se que o efeito da presença das nanoargilas OVMT e OMMT foi semelhante ao efeito da Cloisite®. As propriedades reológicas dos nanocompósitos foram comparáveis às do 4,0% SBS MB, identificando uma redução de custos, dado o potencial de substituição de polímero pela argila. A presença da OVMT melhorou a estabilidade à estocagem do SBS MB, um resultado importante, visto que a separação de fases é um dos maiores obstáculos ao uso do SBS na pavimentação

Background Lentinula edodes, known as shiitake, has been utilized as food, as well as, in popular medicine, moreover, compounds isolated from its mycelium and fruiting body have shown several therapeutic properties. The aim of this study was to determine the antiviral activity of aqueous (AqE) and ethanol (EtOHE) extracts and polysaccharide (LeP) from Lentinula edodes in the replication of poliovirus type 1 (PV-1) and bovine herpes virus type 1 (BoHV-1). Methods The time-of-addition assay was performed at the times -2, -1, 0, 1 and 2 h of the infection. The virucidal activity and the inhibition of viral adsorption were also evaluated. Plaque assay was used to monitor antiviral activity throughout. Results The AqE and LeP were more effective when added at 0 h of infection, however, EtOHE was more effective at the times 1 h and 2 h of the infection. AqE, EtOHE and LeP showed low virucidal activity, and the inhibition of viral adsorption was not significant. Conclusions The results allowed us to conclude that AqE, EtOHE and LeP act on the initial processes of the replication of both strains of virus.

Hydrogels have been prepared by free-radical solution copolymerization of acrylamide and sodium acrylate (NaAc), with molar ratio ranging from 25/75 to 80/20, respectively, using methylene bisacrylamide as the crosslinking agent. A FTIR spectroscopy procedure to determine the acrylate/acrylamide ratio in these hydrogels was proposed based on absorbance at 1410 cm-1 (nCOO-) and 2940 cm-1 (nCH and nCH2). A straight line with a good linear correlation coefficient (0.998) was obtained by plotting the acrylate content (Ac%) versus relative absorbance (Arel = A1410/A2940). Results were confirmed by the amount of sodium cation released in acid medium determined by atomic absorption spectrometry.

Natural products are an inexhaustible source of compounds with promising pharmacological activities, including antiviral action. In the present study, the antiviral potential of polysaccharide-peptide (PLS) and an extracted β-glucan from Agaricus brasiliensis were investigated in the replication of bovine herpesvirus 1 (BoHV-1) in HEp-2 cell cultures. The cytotoxicity (CC50) was assayed by the MTT method and the antiviral activity (IC50) was estimated by the plaque reduction assay. To study the possible mode of action of PLS and β-glucan, the following protocols were performed: the virucidal assay, adsorption assay and the time-of-addition assay. The PLS presented a selectivity index (SI) higher than 12.50 and β-glucan 9.19. The antiviral inhibition (67.9%) in cells treated with PLS during virus infection was higher than that in cells treated prior to or post infection. The β-glucan presented high inhibition of virus replication by plaque assay (83.2%) and by immunofluorescence assay (63.8%). Although the mechanism has yet to be defined, we suggest that PLS and β-glucan inhibited BoHV-1 replication by interfering with the early events of viral penetration. Additional studies are required for a better understanding of the mechanism of action of PLS and β-glucan.

Cashew nut shell liquid (CNSL) is a by-product of the cashew kernel industry, applied mainly to produce polymeric derivatives. The technical CNSL (CNSLT) was obtained industrially, extracted by roasting the cashew nut shells at temperatures between 180 and 200 °C. Two methods were used to produce natural CNSL. For the extraction of CNSLNP, the cashew nut shells were pressed at room temperature. CNSLNS was extracted in hexane at room temperature and recovered at 50 °C. A comparison was made of the composition determined by HPLC and properties generated by viscosity measurements and also by TG, DSC and IPDT (integral procedural decomposition temperature). Natural CNSLs displayed higher content of cardol and anacardic acid and lower percentage of cardanol than CNSLT. The higher content of cardanol in CNSLNS was the major difference between natural CNSLs. CNSLNP had higher levels of impurity, higher viscosity, lower thermoxidative stabilities and lower ebullition temperature. The CNSL obtained by cold solvent extraction and recovery at 50 °C better preserves the original properties of the liquid.

The effects of annealing on the properties of unfermented (polvilho doce-PD) and fermented (polvilho azedo-PAD) cassava starches were studied. The samples were submitted to annealing treatment for 24, 72, 96, 144, 192 and 240 hours. The annealing treatment changed the main physicochemical (gelatinization, enthalpy and temperature) and rheological properties (swelling power, peak viscosity and pasting temperature) of the both samples. The increase in the gelatinization temperatures and the narrowing of the gelatinization range was attributed to an reinforcement in the packing of the double helices of the amylopectin. The PAD samples seemed to be more affected by this treatment than PD ones. The PAD samples presented some characteristics of a waxy starch, such as increased crystallinity and increased stability of the pastes, which from a technological point of view is very important to diversify further its use in the food industry.

In recent years a great interest in the study of the association of magnetic with biological material for bioapplica- tions has been observed in the literature. This work analyses the development of new magnetic biocomposite films from a magnetic ferrite and a biopolymer. Magnetic and dielectric properties of Y3Fe5O12 (YIG)/collagen composite films were studied as a function of the YIG concentration. This biocomposite was also characterized by Infrared Spectroscopy (IR), Thermal Analysis (DSC and TG) and scanning electron microspcopic (SEM) methods. The magnetization and dielectric measurements were performed at room temperature. The results demonstrated that ferrimagnetic garnet (YIG) and collagen (Col) can be used to obtain a homogeneous composite. All the composite films showed a ferromagnetic behavior and they were characterized as a soft magnet material. These results show that Col-YIG biocomposites are biological films with magnetic properties that can be employed as a versatile performance materials, due to their flexible dielectric and magnetic features. They could be used as electronic devices in biological applications.

The effect of iron oxides particles mixed in natural rubber (NR) or aged natural rubber (ANR) from Manihot glaziovii were investigated. IR spectroscopy showed that α-Fe2O3 inhibits or retards the thermal degradation (200°C) of ANR, but it does not inhibit or retard the thermal degradation of NR. A retardation effect is observed using iron (III) oxide in both ANR and NR. Using both oxides, longer autoxidation induction periods of ANR and NR are observed (150°C). The periods were extended for a higher content of rubber hydroperoxide concentration. The inhibition or retardation of autoxidation using Fe3O4 in both ANR and NR is not evident. We suggest an interaction between hydroxyl groups of hydroperoxide, mainly present in aged natural rubber, and the iron oxide surface.

The solubilisation of two poorly soluble flavonoids, quercetin and rutin, in micellar solutions of mixtures of a block copolymer of ethylene oxide and styrene oxide (E(137)S(18)E(137)) with one of ethylene oxide and propylene oxide (E(62)P(39)E(62)) has been studied at 25 and 37 degrees C. Solubilisation capacities were higher than those for the model poorly water-soluble drug griseofulvin and comparable with published values for the solubilisation of rutin by beta-cyclodextrin.