β-Cyclodextrin Inclusion Complex to Improve Physicochemical Properties of Pipemidic Acid: Characterization and Bioactivity Evaluation

The aptitude of cyclodextrins (CDs) to form host-guest complexes has prompted an increase in the development of new drug formulations. In this study, the inclusion complexes of pipemidic acid (HPPA), a therapeutic agent for urinary tract infections, with native β-CD were prepared in solid state by kneading method and confirmed by FT-IR and ¹H NMR. The inclusion complex formation was also characterized in aqueous solution at different pH via UV-Vis titration and phase solubility studies obtaining the stability constant. The 1:1 stoichiometry was established by a Job plot and the inclusion mechanism was clarified using docking experiments. Finally, the antibacterial activity of HPPA and its inclusion complex was tested on P. aeruginosa, E. coli and S. aureus to determine the respective EC_50s and EC_90s. The results showed that the antibacterial activity of HPPA:β-CD against E. coli and S. aureus is higher than that of HPPA. Furthermore, HPPA and HPPA:β-CD, tested on human hepatoblastoma HepG2 and MCF-7 cell lines by MTT assay, exhibited, for the first time, antitumor activities, and the complex revealed a higher activity than that of HPPA. The use of β-CD allows an increase in the aqueous solubility of the drug, its bioavailability and then its bioactivity.     

Design and performance evaluation of ContentPlace,a social-aware data dissemination system for opportunistic networks

In this paper we present and evaluate ContentPlace, a data dissemination system for opportunistic networks, i.e., mobile networks in which stable simultaneous multi-hop paths between communication endpoints cannot be provided. We consider a scenario in which users both produce and consume data objects. ContentPlace takes care of moving and replicating data objects in the network such that interested users receive them despite possible long disconnections, partitions, etc. Thanks to ContentPlace, data producers and consumers are completely decoupled, and might be never connected to the network at the same point in time. The key feature of ContentPlace is learning and exploiting information about the social behaviour of the users to drive the data dissemination process. This allows ContentPlace to be more efficient both in terms of data delivery and in terms of resource usage with respect to reference alternative solutions. The performance of ContentPlace is thoroughly investigated both through simulation and analytical models.     

Foam-like scaffolds for bone tissue engineering based on a novel couple of silicate-phosphate specular glasses: synthesis and properties

Glass–ceramic scaffolds mimicking the structure of cancellous bone were produced via sponge replication technique by using a polyurethane foam as template and glass powder below 30 μm as inorganic phase. Specifically, a SiO₂-based glass of complex composition and its corresponding P₂O₅-based “specular” glass were used as materials for scaffolding. The polymeric sponge was thermally removed and the glass powders were sintered to obtain a replica of the template structure. The scaffolds were investigated and compared from a structural, morphological and mechanical viewpoint by assessing their crystalline phases, volumetric shrinkage, pores content and interconnection, mechanical strength. In addition, the scaffolds were soaked in acellular simulated body fluid to investigate their in vitro behaviour. The produced scaffolds have a great potential for bone reconstructive surgery because their features, such as shape, strength, bioactivity and bioresorption, can be easily tailored according to the end use.     

Vinylene-linked pyridine-pyrrole donor–acceptor conjugated polymers

Vinylene-linked donor–acceptor–donor semiconducting polymers have been prepared by electropolymerization of the new monomers 2,6-bis[(E)-2-(1-methylpyrrol-2-yl)vinyl]pyridine and 2,5-bis[(E)-2-(1-methylpyrrol-2-yl)vinyl]pyridine. The monomers, consisting of two pyrrole donor units and a central pyridine acceptor ring spaced by vinylene links, differ by the substitution pattern around the central pyridine core (2,6 vs. 2,5-substitution). The electropolymerization process is more efficient on the 2,5-derivative. The new polymers show reversible electrochemistry dominated by a strong charge trapping effect. Poly(2,5-bis[(E)-2-(1-methylpyrrol-2-yl)vinyl]pyridine) energy levels closely match those of design rules for optimized polymers in combination with fullerene derivatives in bulk heterojunction solar cells.     

Residual Stresses in Alumina/Zirconia Composites: Effect of Cooling Rate and Grain Size

Alumina/zirconia composites with various compositions at the zirconia-rich part of the phase diagram have been prepared with various grain sizes of the starting alumina powders. After firing under identical conditions, the pellets have been cooled systematically, changing the cooling rates from 0.5 to 8000 K/min. Subsequently, the residual stresses in alumina have been determined by monitoring the frequency shifts of the R ₂ luminescence line of alumina (14 430 cm⁻¹). The data indicate that the stress in alumina is compressive in all cases, with increasing absolute values of the stress with decreasing alumina content. Within the same composition, the residual stress as a function of the cooling rate presents a minimum for values between 10 and 100 K/min, with no clear dependence on the alumina or zirconia grain size. An interpretation of the experimental data in terms of a Coble-type diffusional relaxation applies for intermediate cooling rates (from 10 to 800 K/min), but it fails to account for the large stresses at low cooling rates. The width of the stress distribution is narrow (∼150 MPa) and constant for all compositions and grain sizes at low cooling rates, but it increases for cooling rates >10 K/min, depending on the grain size but not on the composition. For fast cooling rates, a correlation is found when reporting the average width of the stress distribution as function of the average sintered grain-size distribution of alumina. Overall, zirconia grain size seems to influence the average stress, whereas alumina grain size determines the stress distribution.     

Gold nanoparticles induce cytotoxicity in the alveolar type-II cell lines A549 and NCIH441

Background  

During the last years engineered nanoparticles (NPs) have been extensively used in different technologies and consequently many questions have arisen about the risk and the impact on human health following exposure to nanoparticles. Nevertheless, at present knowledge about the cytotoxicity induced by NPs is still largely incomplete. In this context, we have investigated the cytotoxicity induced by gold nanoparticles (AuNPs), which differed in size and purification grade (presence or absence of sodium citrate residues on the particle surface) in vitro, in the human alveolar type-II (ATII)-like cell lines A549 and NCIH441.     

Two-Level State Estimation With Local Measurement Pre-Processing

This paper presents a two-level state estimation methodology intended to integrate in a simple and efficient manner the results provided by local estimators, handling measurements at the substation level, within the framework of existing EMS. This leads to a paradigm in which raw measurements are locally pre-processed by a linear estimator, in such a way that only a manageable subset of measurements is handled at the second level, significantly reducing the communication bandwidth. Simulation results show that, even when the two steps are centrally carried out, the proposed approach is computationally more efficient than the conventional one, particularly with highly redundant measurement sets.