The tartaric acid-modified enzyme-resistant dextrin from potato starch as potential prebiotic

Enzyme-resistant dextrin, obtained as a result of heating potato starch with tartaric acid, was tested as the carbon source for selected strains of probiotic bacteria and also bacteria isolated from feces of healthy 30-year old men volunteers. The dynamics of growth of bacterial monocultures in broth containing tartaric acid (TA)-modified dextrin was estimated. It was also investigated whether probiotic lactobacilli and bifidobacteria cultured with intestinal bacteria in the presence of resistant dextrin would be able to dominate the intestinal isolates. Prebiotic fermentation of resistant dextrin was analyzed using prebiotic index (PI). Fermentation products were determined by HPLC. It was shown that all of the tested bacteria were able to grow and utilize TA-modified dextrin as a source of carbon, albeit to varying degrees. In co-cultures of intestinal and probiotic bacteria, the environment was found to be dominated by the probiotic strains of Bifidobacterium and Lactobacillus, which is a beneficial effect.     

Storage stability of prebiotic fermented milk obtained from permeate resulting of the microfiltration process

The permeate, obtained from the best microfiltration process, was employed in the preparation of fermented milks, without inulin (control) and with 5 g 100 g^?1 inulin (prebiotic), stored at 5 ± 1 °C for 28 days. It could be verified that the storage period and addition of inulin increased the total solids and carbohydrate contents, the caloric value and the acidity, and decreased the pH. The addition of inulin resulted in a fermented product with a lower syneresis index, and greater firmness and cohesiveness. The inulin employed resulted in a product with a greater tendency toward a greenish coloration.     

Microstructural evaluation of poly(vinyl alcohol)‐based hydrogels obtained by freezing‐thawing technique: Thermal analysis and positron annihilation

In this work, semi‐interpenetrating polymer network (s‐IPN) hydrogels of poly(vinyl alcohol) (PVA) with different contents of water‐soluble sulfonated polyester (PES) were obtained by freezing and thawing cycles. The samples were characterized by positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimetry (DSC). PALS was used to determine the average free volume radius through lifetime measures of the ortho‐positronium (o‐Ps). Degree of crystallinity of the PVA/PES hydrogels was evaluated using the melting enthalpy ratios between the samples and the 100% crystalline PVA. The results show that an increase on the PES content leads to a decrease on the degree of crystallinity of the samples, reflecting an increase on the lifetimes (τ₃). These structural changes could be interpreted as a result of different polymer‐polymer interactions between PVA and PES in the hydrogels. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of Quercetin on Paraoxonase 2 Levels in RAW264.7 Macrophages and in Human Monocytes�C�CRole of Quercetin Metabolism

There is increasing evidence that the intracellular antioxidant enzyme paraoxonase 2 (PON2) may have a protective function in the prevention of atherogenesis. An enhancement of PON2 activity by dietary factors including flavonoids is therefore of interest. In the present study we determined the effect of quercetin on paraoxonase 2 levels in cultured murine macrophages in vitro and in overweight subjects with a high cardiovascular risk phenotype supplemented with 150 mg quercetin/day for 42 days in vivo. Supplementation of murine RAW264.7 macrophages in culture with increasing concentrations of quercetin (1, 10, 20 μmol/L) resulted in a significant increase in PON2 mRNA and protein levels, as compared to untreated controls. Unlike quercetin, its glucuronidated metabolite quercetin-3-glucuronide did not affect PON2 gene expression in cultured macrophages. However the methylated quercetin derivative isorhamnetin enhanced PON2 gene expression in RAW264.7 cells to similar extent like quercetin. Although supplementing human volunteers with quercetin was accompanied by a significant increase in plasma quercetin concentration, dietary quercetin supplementation did not change PON2 mRNA levels in human monocytes in vivo. Current data indicate that quercetin supplementation increases PON2 levels in cultured monocytes in vitro but not in human volunteers in vivo.     

The universe of propositional approximations

The idea of approximate entailment has been proposed by Schaerf and Cadoli [Tractable reasoning via approximation, Artif. Intell. 74(2) (1995) 249–310] as a way of modelling the reasoning of an agent with limited resources. In that framework, a family of logics, parameterised by a set of propositional letters, approximates classical logic as the size of the set increases.     

The synthesis and sintering behaviour of BaZr0.9Y0.1O3−δ powders prepared by spray pyrolysis

Powders of BaZr_0.9Y_0.1O_3?δ (BZY10) were synthesised by spray pyrolysis from nitrate salt solutions for the first time. Differences in the powders produced were explored when the concentration of solution, atomisation frequency, aerosol flow rate and furnace temperature were varied. X-ray powder diffraction (XRD) was used to determine that powders produced using a furnace temperature of 800 °C were of single phase. Powder that was produced using a higher atomisation frequency and a lower salt solution concentration resulted in a favourable particle size distribution and morphology for sintering. A density of approximately 91% of the theoretical density (TD) was achieved by sintering at 1500 °C for 1 h in flowing air, significantly higher than is achieved with commercial BZY10 powders using these conditions. This constitutes a significant lowering of the sintering temperature of this oxide.     

Oxygen diffusion in Ti–10Mo alloys measured by mechanical spectroscopy

The addition of interstitial elements in metals, as titanium and its alloys, causes alterations in their mechanical properties, making them either softer or harder, for example. The internal friction measurements have been frequently used in order to verify the behavior of these interstitials atoms in metallic alloys. This paper presents the oxygen diffusion in Ti–10Mo alloy by the analysis of the mechanical relaxation spectra, in the temperature range of 350–600 K. The relaxation structure obtained was analyzed by means of the frequency dependence of the peak temperature and by using a simple mathematical treatment of the relaxation structure and the Arrhenius law.     

Effect of king palm (Archontophoenix alexandrae) flour incorporation on physicochemical and textural characteristics of gluten-free cookies

The replacement of the blend of rice flour (70%) and corn starch (30%) with king palm flour [ Archontophoenix alexandrae (F. Muell.) H. Wendl. and Drude] at levels of 0–30% was investigated for its effects on the chemical and physical characteristics of gluten-free dough and cookies. Cookies containing 10, 20 and 30% of king palm flour were analysed by twenty-one celiac consumers through preference-ranking test. Ash, minerals, and dietary fibre contents increased in cookies that were added with king palm flour. Compared with the control dough, the incorporation of king palm flour increased the firmness and decreased the adhesiveness of dough samples. The incorporation of king palm flour increased the hardness of cookies in relation to the control dough. None of the cookies differed significantly ( P  > 0.05) in the lightness (L*) parameter. All formulations produced cookies with hue angles around 60, which indicate a tendency to brown colour. The study reveals that the incorporation of king palm flour showed desirable results in nutritional characteristics, because of the increase of the dietary fibre and minerals contents. In this study, the cookies preferred by celiac consumers were those containing 10 and 20% of king palm flour ( P  > 0.05).     

Effects of biosilicate and bioglass 45S5 on tibial bone consolidation on rats: a biomechanical and a histological study

The purpose of this study was to investigate the effects of Bioglass 45S5^® and Biosilicate^®, on bone defects inflicted on the tibia of rats. Fifty male Wistar rats were used in this study, and divided into five groups, including a control group, to test Biosilicate^® and Bioglass^® materials of two different particle sizes (180–212 μm or 300–355 μm). All animals were sacrificed 15 days after surgery. No significant differences (P > 0.05) were found when values for Maximal load, Energy Absorption and Structural Stiffness were compared among the groups. Histopathological evaluation revealed osteogenic activity in the bone defect for the control group. Nevertheless, it seems that the amount of fully formed bone was higher in specimens treated with Biosilicate^® (granulometry 300–355 μm) when compared to the control group. The same picture occurred regarding Biosilicate^® with granulometry 180–212 μm. Morphometric findings for bone area results (%) showed no statistically significant differences (P > 0.05) among the groups. Taken together, such findings suggest that, Biosilicate^® exerts more osteogenic activity when compared to Bioglass^® under subjective histopathological analysis.     

Cytotoxicity study of some Ti alloys used as biomaterial

An implanted material is considered biocompatible, if adverse and uncontrollable reactions don't exist in the biological system. In this sense, biocompatibility tests made in the constituent materials are very important so that the implants have success. The in vitro cytotoxicity tests represent the initial phase of the process, and could be considered as a pre-selection of those materials. In vitro techniques using cell culture have become widely used in the evaluation of biomaterial cytotoxicity, which has contributed to their standardization and the substitution of in vivo tests. This paper shows a study of the in vitro cytotoxicity of two Ti based alloys, Ti–13Nb–13Zr and Ti–35Nb–7Zr–5Ta, in the as-received condition and after heat treated. The results show that the alloys presented no cytotoxic effects in the studied conditions.