Boosting TiO2-anatase antimicrobial activity: Polymer-oxide thin films

TiO₂ incorporation into an isotactic polypropylene (iPP) polymeric matrix was achieved via a straightforward and cost-effective melting process using laboratory-made nanometric anatase-TiO₂ and an industrial polymer. The structural characteristics of the resulting nanocomposite thin films as a function of the inorganic component content were examined using wide and small angle X-ray scattering (WAXS/SAXS) and vibrational Raman spectroscopy. Electron scanning and transmission microscopy (SEM/TEM) studies were also performed to provide evidence of the nanometric dispersion of the oxide within the polymer matrix, showing the presence of average aggregates of ca. 80 nm. TiO₂ incorporation into the iPP renders self-sterilized nanocomposite films upon light excitation, the activity of which was tested against Gram negative (P. aeruginosa) and positive (E. faecalis) bacteria. TiO₂ displays maximum activity for a sample containing a 2 wt.% of anatase-TiO₂ irrespective of the microorganism nature. The antimicrobial activity of the nanocomposite films is significantly enhanced with respect to that of the oxide alone. This key fact is interpreted on physical basis with the help of a complete optical (UV–vis and photoluminescence) and electron paramagnetic resonance (EPR) characterization.     

An ontology,intelligent agent-based framework for the provision of semantic web services

Intelligent agents and semantic web services are two technologies with great potential. Striking new applications can be developed by using the tools and techniques they provide. However, semantic web services need for an upper software entity able to deal with them and, on the other hand agent technology has historically suffered from a number of drawbacks that must be addressed. Integrating these two technologies in a joint environment can overcome their problems while strengthening their advantages. In this paper, the necessity for integrating these technologies and the potential benefits of their combination are analyzed. Based on this study, we present SEMMAS, an ontology-based framework for seamlessly integrating Intelligent Agents and Semantic Web Services. The basics of the framework are detailed and a proof-of-concept implementation described.     

Phosphoric and boric acid activation of pine sawdust

Chemical activation of pine sawdust using aqueous solutions of phosphoric and boric acid was studied. Thermogravimetric analyses of the impregnated lignocellulosic precursor as well as their reactivities are presented. The role of the activating agents in the thermal decomposition of the precursor and their effects on the development of porosity in activated carbons is discussed. The use of boric acid as activating agent and a final heat treatment temperature (HTT) of 600 °C produced some porosity and activated carbons with a surface area of 600 m² g^?1. With a HTT of 450 °C, molecular sieve‐like materials were produced. In contrast, phosphoric acid activation produced activated carbons with high surface areas. The amount of phosphoric acid retained in the precursor was, as expected, a function of the initial concentration as well as the impregnation time and temperature. The fact that the activated carbon porosity increases with the phosphoric acid content per gram of precursor was confirmed. The use of 6 M phosphoric acid solution and HTT of 450 °C produced the activated carbon with the highest surface area, about 1600 m² g^?1. The high degree of microporosity which developed in phosphoric acid‐activated carbons is related to the low reactivity during the thermal treatment of chemical activation. The presence of up to 10% oxygen during HTT with phosphoric acid activation caused only small textural changes. Copyright © 2003 Society of Chemical Industry     

Induction of nitric oxide synthases early in pregnancy

OBJECTIVE: We have previously demonstrated that calcium-dependent nitric oxide synthase is induced by estrogen and that by the end of pregnancy nitric oxide synthase of both endothelial and neuronal origin is increased in various maternal tissues. This rise in activity may be crucial for the alterations in muscle activity necessary for a successful pregnancy. If so, the increase in nitric oxide synthase activity must occur early in gestation. STUDY DESIGN: We tested the hypothesis that pregnancy increases nitric oxide synthase activity early in gestation by measuring in heart, kidney, skeletal muscle, and esophagus of time-mated guinea pigs the conversion by nitric oxide synthase of carbon 14-labeled L-arginine to carbon 14-labeled citrulline and the concentration of cyclic guanosine monophosphate, the second messenger of nitric oxide. RESULTS: Calcium-dependent nitric oxide synthase activity was increased twofold to fourfold by pregnancy in each tissue examined. The rise began by 0.14 gestation (9 of 63 +/- 2 days) and reached a plateau by 0.30 gestation (19 days), which was then maintained until term. The treatment of pregnant animals with tamoxifen decreased nitric oxide synthase activity to nonpregnant values in the heart, where tamoxifen is an estrogen receptor antagonist, but not in kidney, skeletal muscle, and esophagus. Cyclic guanosine monophosphate also rose progressively in each tissue studied until about 0.70 gestation before declining in skeletal muscle, kidney, and heart. It remained elevated in the esophagus. CONCLUSION: These studies demonstrate that nitric oxide synthase activity in maternal tissues rises early in pregnancy and is associated with an increase in cyclic guanosine monophosphate, the second messenger of nitric oxide. These findings are consistent with the hypothesis that an increase in nitric oxide synthase plays a role in smooth muscle adaptations of pregnancy.     

Vicissitudes of autobiographical memories in a bilingual analysis.

Discusses repression in bilingual analyses, including repressed memories, transference, and dreams, as well as the whole associative process. As certain memories are more accessible in one language than the other, repression for bilingual individuals may be partly a function of linguistic accessibility. The concept of repression will therefore need to be reassessed in the context of these observations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can cumulative tobacco consumption, FTND score, and carbon monoxide concentration in expired air be predictors of chronic obstructive pulmonary disease?

Between 15% and 20% of smokers develop chronic obstructive pulmonary disease (COPD). The aim of the present study was to determine which characteristics of smoking, particularly the Fagerstr?m Test for Nicotine Dependence (FTND) score, were associated with the risk of developing COPD. Data from the IBERPOC epidemiological study were analyzed. IBERPOC was a multicenter epidemiological study including 4035 individuals aged 40-69 years, 1023 (25%) of whom were active smokers. We analyzed the association between smoking characteristics--such as the cumulative consumption of tobacco, FTND score, and expired-air carbon monoxide levels--and the diagnosis of COPD. Among the smokers, 153 (15%) were diagnosed with COPD. A cumulative tobacco consumption of more than 30 pack-years (OR=4.24, 95% CI=2.83-6.36) and the FTND score (OR=1.11, 95% CI=1.02-1.21, for each point increase) were significantly associated with the diagnosis of COPD in the model obtained by logistic regression analysis with the full sample of smokers. Cumulative consumption of tobacco was associated with the diagnosis of COPD. For each point increase in the FTND score, the probability of a smoker developing COPD increased by 11%.     

Nitric oxide synthase. Structural studies using anti-peptide antibodies

The amino acid sequence for the constitutive rat brain nitric oxide (NO) synthase was analysed by a set of computer programs that estimate and display physicochemical properties such as hydrophilicity, flexibility, accessibility, hydrophilic periodicity and conformation [Comerford, S. A., McCance, D. J., Dougan, G. & Tite, J. P. (1991) J. Virol. 65, 4681-4690]. Overall, they allow prediction of whether each peptide region will be an alpha-helix, a beta-strand or a less regular coil and also whether the region will be buried in the protein core or exposed to water at the surface of the protein molecule. Ten peptide regions were chosen; the majority were predicted to be exposed areas of the molecule and therefore likely to be immunogenic. The peptides were chemically synthesised, coupled to keyhole limpet haemocyanin carrier protein and injected into rabbits to raise antibodies. These antibodies have been used by us and others to locate the NO synthase in different tissues and species. Here we present the characterisation of the antibodies in relation to the possible conformation of the enzyme and an immunological comparison between two isoforms of NO synthase: constitutive (rat brain) and inducible (macrophage). Peptide regions predicted to be exposed, flexible or substantially in core, have produced antibodies that were able to recognise the native protein. Peptides of mixed characteristics possibly involved in the binding site tended to produce antibodies with low recognition for the tertiary structure of the native, purified NO synthase, although these peptides were all highly immunogenic. We postulate that either the peptides when conjugated to the carrier protein attain a different conformation to that in the native NO synthase, or alternatively the accessibility of the antibodies to substrate binding sites is highly restricted by steric hindrance. This latter seems to be more likely since a mixture of antibodies against this area of the protein molecule was able to achieve a similar neutralisation of the enzyme activity as the antibodies against the whole enzyme (approximately 50%). Most of the selected anti-peptide antibodies were not able to cross-react with the inducible macrophage enzyme; only two that have 60% sequence identity showed a weak reaction in Western blot. The polyclonal antibody against the complete brain enzyme showed cross-reaction in a Western blot with inducible enzyme. The macrophage enzyme was able to compete weakly with the binding of the brain enzyme to its own antibody, but 10 times more inducible protein was required.(ABSTRACT TRUNCATED AT 400 WORDS)     

Arc crossing minimization in hierarchical digraphs with tabu search

Graphs are used commonly as a basic modeling tool in areas such as project management, production scheduling, line balancing, business process reengineering, and software visualization. An important problem in the area of graph drawing is to minimize arc crossings in a multi-layer hierarchical digraph. Existing solution methods for this problem are based on simple ordering rules for single layers that may lead to inferior drawings. This article first introduces an extensive review of relevant work previously published in this area. Then a tabu search implementation is presented that seeks high-quality drawings by means of an intensification phase that finds a local optimum according to an insertion mechanism and two levels of diversification. Computational experiments with 200 graphs with up to 30 nodes per layer and up to 30 layers are presented to assess the merit of the method.     

C-HEAP: A Heterogeneous Multi-Processor Architecture Template and Scalable and Flexible Protocol for the Design of Embedded Signal Processing Systems

The key issue in the design of Systems-on-a-Chip (SoC) is to trade-off efficiency against flexibility, and time to market versus cost. Current deep submicron processing technologiesenable integration of multiple software programmable processors (e.g., CPUs,DSPs) and dedicated hardware components into a single cost-efficient IC. Ourtop-down design methodology with various abstraction levels helps designingthese ICs in a reasonable amount of time. This methodology starts with a high-levelexecutable specification, and converges towards a silicon implementation.A major task in the design process is to ensure that all components (hardwareand software) communicate with each other correctly. In this article, we tacklethis problem in the context of the signal processing domain in two ways: wepropose a modular, flexible, and scalable heterogeneous multi-processor architecturetemplate based on distributed shared memory, and we present an efficient andtransparent protocol for communication and (re)configuration. The protocolimplementations have been incorporated in libraries, which allows quick traversalof the various abstraction levels, so enabling incremental design. The designdecisions to be taken at each abstraction level are evaluated by means of(co-)simulation. Prototyping is used too, to verify the system's functionalcorrectness. The effectiveness of our approach is illustrated by a designcase of a multi-standard video and image codec.He currently works with Magma Design Automation. E-mail: