The web from a complex adaptive systems perspective

The web continues to grow at a phenomenal rate, and the amount of information on the web is overwhelming. Finding the relevant information remains a big challenge. Due to its wide distribution, its openness and high dynamics, the web is a complex system, for which we have to imagine mechanisms of content maintaining, filtering and organizing that are able to deal with its evolving dynamics and distribution. Integrating mechanisms of self-organization of the web content is an attractive perspective, to match with these requirements. Self-organized complex systems can be programmed using situated multi-agent systems with a coupling between the agents' social organization and spatial organization. This paper explores the web from a complex adaptive system (CAS) perspective. It reviews some characteristic behaviors of CASs and shows how the web exhibits similar behaviors. We propose a model and a prototype of a system that addresses the dynamic web content organization, adopting the CAS vision and using the multi-agent paradigm.     

Resolution and Constraint Propagation for Semantic Web Services Discovery

The purpose of semantic web services discovery is to use semantic knowledge to find services that can be composed to form an admissible answer to a query. In this paper we consider the advantage of adopting a knowledge-based approach to web services discovery. Services are described by means of terminological axioms and constrained clauses. We apply a specific resolution and a constraint propagation mechanism to evaluate queries over services.Recommended by: Athman Bouguettaya and Boualem Benatallah     

Antiviral and Anticancer Activity of Cisplatin Derivatives of Tilorone

Cisplatin derivatives containing tilorone and a tilorone derivative were synthesized and characterized employing IR analysis, mass spectrometry, elemental analysis, and chain length. The polymeric cisplatin derivatives prevent growth of four transformed cell lines, L929, 143, Vero, and BS-C-1 and effectively inhibit four viruses including the DNA viruses; herpes simplex-1, vaccinia, and Varicella zoster, and the RNA virus, reovirus in the micrograms/mL range. The tilorone polymers display activity against both transformed cells and DNA and RNA viruses at biologically important concentrations.     

The influence of bleeding,extra water and superplasticizer on the SCC plastic shrinkage cracking: case of hot weather

Self-compacting concrete (SCC) is a new material able to be put in place without vibration. However, this advantage is offset by some drawbacks, such as plastic shrinkage, one of the causes of cracking in concrete. Furthermore, the presence of fines absorbs a large amount of water and therefore minimizes bleeding. This paper endeavours to provide a better understanding of the appearance of plastic shrinkage cracking, and to justify his relation with bleeding phenomena. Five SCC formulas with different W/C ratios were prepared and compared to the same range of ordinary concrete (OC) in terms of restrained shrinkage (cracking width). At the same time, a study of cracks’ propagation over time (cracking length) was conducted on the equivalent mortars (mOCe, mSCCe). Mixtures were placed in different hot environmental conditions. The results showed that bleeding significantly reduces cracking length and has no effect on cracking width. In the second part, extra water and superplasticizer was proposed as a solution to prevent SCC cracking and findings show the addition of 10% of water reduces cracking length and a slightly lower addition of superplasticizer reduces SCC’s crack width.     

Chitosan nanoparticles with controlled size and zeta potential

Optimization of chitosan nanoparticles (ChNs) production process employing a 2^(5–2) fractional factorial design was performed to analyze the influence of viscosity average molecular weight (40–120 kDa), the initial concentration of chitosan (2–5 g/L), the initial tripolyphosphate (TPP) concentration (0.8–1.2 g/L), the ratio chitosan/TPP (4/1–10/1) (V/V), and the stirring speed (300–700 rpm), on final nanoparticles size and zeta potential. The measured responses of average particle size and surface charge were determined on Zetasizer Nano ZS. ChNs were prepared using ionotropic cross-linking of chitosan and TPP and were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and differential scanning calorimetry (DSC). The experiments showed that the size of synthesized nanoparticles depended on initial concentration and molecular weight of chitosan, TPP concentration and stirring speed within the chosen levels. However, the zeta potential was significantly influenced by chitosan molecular weight, chitosan concentration and stirring speed. The FTIR analysis confirmed the interaction between negative charge of TPP with positive charge of chitosan through the appearance of new peaks at 1222 and 895 cm⁻¹ in produced ChNs. XRD and DSC analysis were used to evaluate the effect of crosslinking of chitosan on crystal structure of ChNs.