Suspension Rheology,Porosity and Mechanical Strength of Porous Hydroxyapatite Obtained by Gel-casting and Infiltration

The gel-casting technique (GC) and infiltration of polymer foam combined with gel-casting (IG) were used to produce hydroxyapatite porous bodies. Due to the fact that the process begins with the preparation of the suspensions, it is necessary to know the rheological properties of the ceramic slurry. This is a critical factor needed to optimize the mechanical strength of the porous body obtained. Therefore, the rheological behavior of various HA slurries was assessed. 40 and 50% solids and three different monomers were evaluated. Subsequently, the compressive strength and porosity of the porous bodies obtained were evaluated. The results revealed that the chemical composition of each monomer can affect the dispersion and rheological properties of the suspension, which directly affects the mechanical properties of the porous bodies. The porous bodies obtained by the GC technique showed strengths higher than those obtained by IG compression. The control executed over the rheology of the suspension was more effective in bodies produced by GC, because IG pyrolysis of polyurethane foam also influenced the mechanical properties of the final product.     

Antioxidant Systems from Pepper (Capsicum annuum L.): Involvement in the Response to Temperature Changes in Ripe Fruits

Sweet pepper is susceptible to changes in the environmental conditions, especially temperatures below 15 °C. In this work, two sets of pepper fruits (Capsicum annuum L.) which underwent distinct temperature profiles in planta were investigated. Accordingly, two harvesting times corresponding to each set were established: Harvest 1, whose fruits developed and ripened at 14.9 °C as average temperature; and Harvest 2, with average temperature of 12.4 °C. The oxidative metabolism was analyzed in all fruits. Although total ascorbate content did not vary between Harvests, a shift from the reduced to the oxidized form (dehydroascorbate), accompanied by a higher ascorbate peroxidase activity, was observed in Harvest 2 with respect to Harvest 1. Moreover, a decrease of the ascorbate-generating enzymatic system, the γ-galactono-lactone dehydrogenase, was found at Harvest 2. The activity values of the NADP-dependent dehydrogenases analyzed seem to indicate that a lower NADPH synthesis may occur in fruits which underwent lower temperature conditions. In spite of the important changes observed in the oxidative metabolism in fruits subjected to lower temperature, no oxidative stress appears to occur, as indicated by the lipid peroxidation and protein oxidation profiles. Thus, the antioxidative systems of pepper fruits seem to be involved in the response against temperature changes.     

The grammatical approach: A syntax-directed declarative specification method for XML processing tasks

This paper describes the grammatical approach, an approach to the specification of XML processing tasks based on attribute grammars. This approach describes how to provide task-specific context-free grammars for XML documents, as well as how to decompose complex processing tasks into simpler ones with attribute-grammar fragments. The result is a high-level, syntax-directed declarative specification for the processing of XML documents, which facilitates the development and maintenance of complex XML processing applications while preserving the flexibility of general-purpose XML processing models. The grammatical approach is illustrated using Chasqui, an e-learning platform for building educational digital libraries of learning objects.     

New Platinum‐Catalysed Dihydroalkoxylation of Allenes

A new platinum‐catalysed dihydroalkoxylation of allenes is described to give aliphatic acetals by an unexpected attack of two molecules of methanol to the terminal carbon of the allene moiety. Deuteration experiments suggest an unprecedented formal 1,3‐dipolar addition of methanol to a zwitterionic platinum carbene as the key step. The first platinum‐catalysed intermolecular carbon‐based nucleophile addition to allenes is also reported.     

Characterization of hyperbranched polyol polyesters based on 2,2‐bis (methylol propionic acid) and pentaerythritol

Hyperbranched polyesters (HBPs) of fourth and fifth generation were synthesized by procedures involving one step (HBP4, HBP5), step by step (HBP4P, HBP5P), and combination of both of them (HBP1‐4, HBP1‐5) using 2,2‐bis(methylol)propionic acid (DMPA), pentaerythritol (PE), and acid catalysis. The characterization of the polyesters was done by nuclear magnetic resonance (NMR), rheology on solution, Fourier transform infrared spectroscopy (FTIR), and acid and hydroxyl values. The degree of branching of polyesters (DB) and the average molecular mass and polymerization degree _NMR were calculated by Frey and Fréchet methods and (DP)_NMR, respectively, being higher for HBP4P sample. The molecular structure of polyesters depends mainly on of the synthesis method. The hydroxyl values were larger than 430 mg/g KOH for all HBPs, and the conversion was controlled between 90 and 93% to avoid excessive cyclization reactions. The steady shear viscosities at different temperatures and at 41.77 s^?1 shear rate were measured for all HBPs solutions in dimethyl formamide (DMF) showing a shear thickening behavior. The flow activation energies (E_a) were calculated by Arrhenius equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dietary fish oil n-3 fatty acids increase regulatory cytokine production and exert anti-inflammatory effects in two murine models of inflammation

The higher incidence of inflammatory diseases in Western countries might be related, in part, to a high consumption of saturated fatty acids and n−6 polyunsaturated fatty acids (PUFA) and an insufficient intake of n−3 fatty acids. The purpose of this study was to examine the effects of dietary n−3 fatty acids on innate and specific immune response and their anti-inflammatory action in models of contact and atopic dermatitis. Balb/C mice were fed for 3 wk either n−6 or n−3 PUFA-fortified diets. After inducing a contact or an atopic dermatitis, immunological parameters were analyzed to evaluate the anti-inflammatory potential of these n−3 PUFA. n−3 PUFA reduced innate and specific immune responses through inhibition of T_H1 and T_H2 responses, increase of immunomodulatory cytokines such as IL-10, and regulation of gene expression. The inhibition of both kinds of responses was confirmed by the anti-inflammatory effect observed in contact and atopic dermatitis. Reduction in weight, edema, thickness, leukocyte infiltration, and enhancement of antioxidant defenses in the inflamed ears of mice from both models along with the prevention of delayed-type hypersensitivity induced in atopic dermatitis proved n−3 PUFA efficacy. Our data suggest that dietary fish oil-derived n−3 fatty acids have immunomodulatory effects and could be useful in inflammatory disorders.     

Fluorescence Liquid Biopsy for Cancer Detection Is Improved by Using Cationic Dendronized Hyperbranched Polymer

(1) Background: Biophysical techniques applied to serum samples characterization could promote the development of new diagnostic tools. Fluorescence spectroscopy has been previously applied to biological samples from cancer patients and differences from healthy individuals were observed. Dendronized hyperbranched polymers (DHP) based on bis(hydroxymethyl)propionic acid (bis-MPA) were developed in our group and their potential biomedical applications explored. (2) Methods: A total of 94 serum samples from diagnosed cancer patients and healthy individuals were studied (20 pancreatic ductal adenocarcinoma, 25 blood donor, 24 ovarian cancer, and 25 benign ovarian cyst samples). (3) Results: Fluorescence spectra of serum samples (fluorescence liquid biopsy, FLB) in the presence and the absence of DHP-bMPA were recorded and two parameters from the signal curves obtained. A secondary parameter, the fluorescence spectrum score (FS_score), was calculated, and the diagnostic model assessed. For pancreatic ductal adenocarcinoma (PDAC) and ovarian cancer, the classification performance was improved when including DHP-bMPA, achieving high values of statistical sensitivity and specificity (over 85% for both pathologies). (4) Conclusions: We have applied FLB as a quick, simple, and minimally invasive promising technique in cancer diagnosis. The classification performance of the diagnostic method was further improved by using DHP-bMPA, which interacted differentially with serum samples from healthy and diseased subjects. These preliminary results set the basis for a larger study and move FLB closer to its clinical application, providing useful information for the oncologist during patient diagnosis.     

Application of Bayesian networks in prognostics for a new Integrated Vehicle Health Management concept

The aeronautics industry is attempting to implement important changes to its maintenance strategy. The article presents a new framework for making final decision on aeroplane maintenance actions. It emphasizes on the use of prognostics within this global framework to replace corrective and Preventive Maintenance practise for a predictive maintenance to minimize the cost of the maintenance support and to increase aircraft/fleet operability. The main objective of the article is to show the Bayesian network model as a useful technique for prognosis. The specific use case for predicting brake wear on the plane is developed based on this technique. The network allows estimate brake wear from the aircraft operational plan. This model, together with other models to make predictions for various components of the aeroplane (that should be monitored) offers a forward-looking approach of the status of the plane, allowing later the evaluation of different operational plans based on operational risk assessment and economic cost of each one of them depending on the scheduled checks.     

Dead time-dependent line distortions in absolute-value electron spin echo envelope modulation spectra

The 30-base pair (bp) deletion of the cytoplasmic carboxy-terminal domain of the latent membrane protein 1 (LMP-1) gene was analyzed in 37 frozen tissues from patients with Epstein-Barr virus (EBV)-related gastric cancer and 18 throat washings from healthy adults in southern Japan. The 30-bp deletion was identified in 33 (91.7%) of 36 specimens of EBV-related gastric cancers and in 15 (83.3%) of 18 throat washings from healthy adults. In one case of gastric cancer, an additional 9-bp deletion was identified downstream of the 30-bp deletion. From the last transmembrane domain to the end of the carboxy terminal of LMP-1, mutations were examined in 37 cases of gastric cancers and in three cases of throat washings. Twenty-eight nonsilent mutations were identified in this region of EBV-related gastric cancer and throat washings. Five nonsilent mutations at positions 168,755, 168,746, 168,687, 168,357, and 168,355 were identified in all 30-bp-deleted cases of EBV-related gastric cancers and throat washings. However, these nonsilent mutations were not identified in three patients without the 30-bp deletion. Although the deletion and single-base mutations of the LMP-1 gene in gastric cancers and throat washings were similar to those of nasopharyngeal carcinoma in Taiwan and China, more single-base mutations were found in southern Japan. These data indicate that high prevalence of the 30-bp deletion of the LMP-1 gene in gastric cancers may reflect the prevalence of the deletion variant in the normal population in southern Japan.     

Dry reforming of methane over LaNi1−yByO3±δ (B = Mg,Co) perovskites used as catalyst precursor

Perovskites LaNiO₃, LaNi_1−xMg_xO_3−δ and LaNi_1−xCo_xO_3−δ were synthesized by auto combustion method. TPR analysis reveled that Mg or Co substituted perovskites were more difficult to reduce. The perovskites were evaluated as catalyst precursors in the dry reforming of methane. Catalysts obtained by reduction of LaNiO₃ and LaNi_1−xMg_xO_3−δ perovskite had the highest catalytic activity for CO₂ reforming of CH₄ at 700 °C using drastic reaction conditions (10 mg of catalyst, a mixture of CH₄/CO₂ without dilution gas). Methane and carbon dioxide conversions were 57% and 67%, respectively, with a H₂/CO ratio equal to 0.47.The presence of cobalt leads to a decrease of the catalytic activity. This decreasing of activity may be attributed to the Co–Ni alloy formation. Computational calculations revealed that Ni atom cleaves the C–H atom while Co is not able to activate the CH₄ molecule. The interaction energy of CH₄ with the Ni and CO atom was 18 kcal/mol and 0.7 kcal/mol, respectively.The catalysts were characterized by TPR, TEM and in situ XRD.