Voltammetric, EQCM, and in situ conductance studies of p- and n-dopable polymers based on ethylenedioxythiophene and bithiazole

New co-oligomers based on 4,4′-dialkyl-2,2′-bithiazole and 3,4-ethylene-dioxythiophene (EDOT) in a donor-acceptor type molecule were obtained using organometallic polycondensation mediated by organotransition metal complexes. The properties of electrochemically obtained polymer films from these monomers were characterized by cyclic voltammetry combined with in situ conductivity, UV-vis spectra, and electrochemical quartz microbalance (EQCM) method.     

Inhibition of the corrosion of stainless steel by poly-N-vinylimidazole and N-vinylimidazole

In this study, we investigated the inhibition of the corrosion of stainless steel (SS) in acidic solution by N-vinylimidazole monomer (NVI) and poly-N-vinylimidazole (PNVI). First, we have synthesized a polymer sample of PNVI from the monomer NVI. A stainless steel electrode was coated with this polymer as a thin film by dipping method. Corrosion rates of SS electrodes coated with PNVI films of different thicknesses were determined and compared with the results of the bare electrode in acidic solution. Corrosion rates of the bare SS electrodes were also compared with the rates in the presence of monomer and polymer, respectively, in the acidic solution. The corrosion currents were obtained by Tafel extrapolation from anodic and cathodic polarization curves. Electrochemical impedance spectroscopy (EIS) measurements were also carried out. Values of percent inhibition, wetted area and porosity were obtained for SS electrodes coated with PNVI films of different thicknesses.     

Voltammetric, EQCM, and in situ conductivity studies of 3,6-bis(2-thienyl)-N-ethyl carbazole

3,6-Bis(2-thienyl)-N-ethylcarbazole (Th-ECz-Th) was obtained by using organometallic polycondensation mediated by organotransition metal complexes. The properties of electrochemically obtained polymer films from this monomer were characterized by simultaneous voltametric and in situ conductivity and electrochemical quartz microbalance techniques.     

Impact of molecular structure of polymer in 193 nm resist performance

Miniaturization in microelectronic technologies requests a development of new high-performance materials for microlithography with good resolution of the critical dimension. However, the real impact of polymer structure on lithographic performances is not yet well understood to predict the properties of formulated resist. Our approach is the synthesis and characterization of model resists and the understanding of the relationship between material – properties – processes. In this work we present the influence of the polymer’s molecular weight in lithographic profile of the generated patterns. The limits of the polymer’s molecular weight values based on model terpolymers, consisting of methacrylate matrix, for efficient patterning have been identified. Finally, the ineffective sensitivity and dissolution issue of the polymer resists having an average molecular weight of 30 kg/mol was extensively examined and attributed to the molecular weight of the polymer and more precisely to the radius of gyration of the polymer.     

Molecularly imprinted hydrogels for fibrinogen recognition

Molecularly imprinted hydrogels (MIHs) composed of N-isopropylacrylamide (NIPA) and maleic acid (MA) monomers and fibrinogen (Fbg, MW: 340 kDa, pI: 5.8) imprinted molecule were fabricated in pH buffer solutions (pH_prep: 4.0, 5.8 and 8.0). The non-imprinted hydrogels were also prepared in the same conditions without Fbg imprinted molecule. The adsorption equilibrium constant and the maximum adsorption capacity of the MIH prepared in pH 4.0 were evaluated to 9.61 mL mg^?1 and 38.99 mg protein g^?1 dry gel in pH 4.0 buffer solution, respectively. The selectivity tests were also performed by using two reference molecules as bovine serum albumin (BSA, MW: 67 kDa, pI: 4.78) and urease (MW: 480 kDa, pI: 5.99). The MIHs have 2.37–4.23 times higher selectivity for the Fbg imprinted molecule than the non-imprinted hydrogels prepared in the same conditions. Easy preparation of the MIHs, their high stability and ability to recognize small and large proteins, as well as to discriminate molecules with small variations in charge, make this approach attractive and broadly applicable in biotechnology, assays and sensors.     

Cultural values and governance quality as correlates of road traffic fatalities: A nation level analysis

This study investigated the relationships between governance quality, cultural dimensions and road traffic fatality rates in a sample of 46 countries. Government quality was measured with six World Governance Indicators (WGI) published by World Bank, and the cultural factors included Hofstede's four cultural dimensions and seven Schwartz value dimensions. Both direct and moderator effects of the WGI on traffic fatality rates per million vehicles were found. Each of the six WGI scores correlated negatively with traffic fatalities indicating that the quality of governance and institutions contribute to traffic safety. Hofstede's “power distance” dimension and Schwartz value dimensions “embeddedness”, “hierarchy” and “mastery” were positively and “intellectual autonomy” and “egalitarianism” negatively related to traffic fatalities. The WGI score moderated the effects of “hierarchy” and “mastery” on traffic fatalities so that in countries with low governance quality these cultural factors had stronger impact on traffic fatalities. It was concluded that improvement of the quality of governance and institutions would also result in improvement in traffic safety.     

Cooperative learning strategies for intelligent tutoring systems

Intelligent tutoring systems (ITS) are evolving towards a more cooperative relationship between the system and the student. More and more, learning is considered as a constructive process rather than a simple transfer of knowledge. This trend has brought to light new cooperative tutoring strategies. One of these tutoring strategies, the learning companion, designed to overcome some of the limitations of the classical tutoring model, involves a student and two simulated participants: a tutor and another student. More recently, a new strategy, learning by disturbing, has been proposed. In this strategy, the simulated student is a troublemaker whose role is to deliberately disturb the human student. This article describes the learning by disturbing strategy by contrasting it with the learning companion strategy. In addition, links are drawn between this new strategy and the psychology of learning, in particular the cognitive dissonance theory. An indicator has been developed that measures discord between the ideas, helping to pinpoint the concepts that are most likely to be misunderstood by the learner. Doing so allows one to plan more efficiently the interventions of the troublemaker.     

Alambic: a privacy-preserving recommender system for electronic commerce

Recommender systems enable merchants to assist customers in finding products that best satisfy their needs. Unfortunately, current recommender systems suffer from various privacy-protection vulnerabilities. Customers should be able to keep private their personal information, including their buying preferences, and they should not be tracked against their will. The commercial interests of merchants should also be protected by allowing them to make accurate recommendations without revealing legitimately compiled valuable information to third parties. We introduce a theoretical approach for a system called Alambic, which achieves the above privacy-protection objectives in a hybrid recommender system that combines content-based, demographic and collaborative filtering techniques. Our system splits customer data between the merchant and a semi-trusted third party, so that neither can derive sensitive information from their share alone. Therefore, the system could only be subverted by a coalition between these two parties.