Modelling of Multi-Agent Systems: Experiences with Membrane Computing and Future Challenges

Formal modelling of Multi-Agent Systems (MAS) is a challenging task due to high complexity, interaction, parallelism and continuous change of roles and organisation between agents. In this paper we record our research experience on formal modelling of MAS. We review our research throughout the last decade, by describing the problems we have encountered and the decisions we have made towards resolving them and providing solutions. Much of this work involved membrane computing and classes of P Systems, such as Tissue and Population P Systems, targeted to the modelling of MAS whose dynamic structure is a prominent characteristic. More particularly, social insects (such as colonies of ants, bees, etc.), biology inspired swarms and systems with emergent behaviour are indicative examples for which we developed formal MAS models. Here, we aim to review our work and disseminate our findings to fellow researchers who might face similar challenges and, furthermore, to discuss important issues for advancing research on the application of membrane computing in MAS modelling.Comment: In Proceedings AMCA-POP 2010, arXiv:1008.314

Experimental investigation of fluid flow in horizontal pipes system of various cross-section geometries

The current research work presents experiments of an essentially incompressible fluid flow in pipes. The experimental equipment consists of a horizontal pipe including a gate valve, a Venturi meter, a wide angle diffuser, an orifice plate, a 90-degree elbow and pressure tappings. An elbow connects the pipe to arotameter with further pressure tappings. All pressure tappings connected to manometers held on a vertical panel behind the pipe work and show pressure at various points. The effect of the pipe geometry in the flow pattern is presented. Furthermore head losses are estimated, at specific stream-wise cross-sections, for mass flow rate numbered from 0.056 to 0.411 l/s. The manometers measure and clearly show pressure distribution against a calibrated scale. The diagrams of mass flow rate and head losses are presented in specific crosssections, where geometry changes. All measurements were calibrated and validated in a maximum standard deviation difference of 5%. The head losses decrease as the mass flow rate decreases, for all pipe geometries. In the future the experimental results can be used to verify numerical simulation results

Smoking behavior among nurses in rural greece

Evidence suggests that rural health care providers may be at increased risk for tobacco addiction. Few researchers have studied the habitual use of tobacco in rural Greece and no published studies have examined sustained tobacco use by nurses working in these areas or their knowledge and attitudes toward smoking cessation. To explore the above, the authors conducted a questionnaire-based study in 40 health centers in rural mainland and island Greece. Two hundred twenty nurses were surveyed (65% response rate). Thirty-two percent of the nurse respondents were smokers, 54% were non-smokers, and 14% were former smokers. Only 8% of respondents had been trained to assist clients with smoking cessation. © American Association of Occupational Health Nurses, Inc

RNA-Mediated therapeutics: From gene inactivation to clinical application

The specific targeting and inactivation of gene expression represents nowdays the goal of the mainstream basic and applied biomedical research. Both researchers and pharmaceutical companies, taking advantage of the vast amount of genomic data, have been focusing on effective endogenous mechanisms of the cell that can be used against abnormal gene expression. In this context, RNA represents a key molecule that serves both as tool and target for deploying molecular strategies based on the suppression of genes of interest. The main RNA-mediated therapeutic methodologies, deriving from studies on catalytic activity of ribozymes, blockage of mRNA translation and the recently identified RNA interference, will be discussed in an effort to understand the utilities of RNA as a central molecule during gene expression

Association of anti-CCP positivity and carriage of TNFRII susceptibility variant with anti-TNF-α response in rheumatoid arthritis

Objective: To investigate the possible influence of tumour necrosis factoralpha (TNF), TNF receptor I (TNFRI) and TNF receptor II (TNFRII) gene polymorphisms on anti-TNF treatment responsiveness, stratified by autoantibody status. Methods: A Greek multi-centre collaboration was established to recruit a cohort of patients (n=100) with active RA treated with anti-TNF drugs. TNF g.-238G>A (rs361525), g.-308G>A (rs1800629), g.-857C>T (rs1799724), TNFRI c.36A>G (rs4149584) and TNFRII c.676T>G (rs1061622) polymorphisms were genotyped by PCRRFLP assays. Serum RF and anti-CCP antibody status were determined using commercially available kits. Single-SNP, haplotype and stratification by autoantibody status analyses were performed in predicting response to treatment by 6 months, defined as the absolute change in DAS28. Results: 31 patients (31%) were defined as non-responders due to failure to fulfill the DAS28 criteria. 79% and 66% were RF and anti-CCP positive, respectively. None of the genotyped SNPs was alone associated with responsiveness to drug treatment. However, after stratification by autoantibody status, carriage of TNFRII c.676G allele was associated with poorer response to drug treatment in anti-CCP positive patients (p=0.03), after 6 months of anti-TNF therapy. Conclusion: In concordance with previous studies, genetic polymorphisms alone cannot be used to safely predict clinical response to anti-TNF therapy however the combination of genetic factors and autoantibody status warrants further investigation in larger independent cohorts. © Clinical and Experimental Rheumatology 2011

Association of anti-CCP positivity and carriage of TNFRII susceptibility variant with anti-TNF-alpha response in rheumatoid arthritis

Objective. To investigate the possible influence of tumour necrosis factor-alpha (TNF), TNF receptor I (TNFRI) and TNF receptor II (TNFRII) gene polymorphisms on anti-TNF treatment responsiveness, stratified by autoantibody status. Methods. A Greek multi-centre collaboration was established to recruit a cohort of patients (n=100) with active RA treated with anti-TNF drugs. TNF g.-238G>A (rs361525), g.-308G>A (rs1800629), g.-857C>T (rsl 799724), TNFRI c.36A>G (rs4149584) and TNFRII c.676T>G (rs1061622) polymorphisms were genotyped by PCR-RFLP assays. Serum RF and anti-CCP antibody status were determined using commercially available kits. Single-SNP, haplotype and stratification autoantibody status analyses were performed in predicting response to treatment by 6 months, defined as the absolute change in DAS28. Results. 31 patients (31%) were defined as non-responders due to failure to fulfill the DAS28 criteria. 79% and 66% were RF and anti-CCP positive, respectively. None of the genotyped SNPs was alone associated with responsiveness to drug treatment. However, after stratification by autoantibody status, carriage of TNFRII c.676G allele was associated with poorer response to drug treatment in anti-CCP positive patients (p=0.03), after 6 months of anti-TNF therapy. Conclusion. In concordance with previous studies, genetic polymorphisms alone cannot be used to safely predict clinical response to anti-TNF therapy however the combination of genetic factors and autoantibody status warrants further investigation in larger independent cohorts