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Recently, drug delivery systems are facing several shortcomings which demand for the development of new formulations. A new drug–solvent systems may improve the characteristics and sustained release of drugs. Investigations in this domain revealed the significance of Ionic Liquids (ILs) as active pharmaceutical ingredients for pharmaceutical applications. ILs–drug assisted carriers exhibit many unique and attractive properties which are lacking in their conventional counterparts. In this work, Chitosan (CS), a natural polymer was blended with an ammonium based IL, Tetramethylammonium hydroxide (TMAOH), and microparticles (MPs) of CS–TMAOH–TPP were synthesized by cross–linking with sodium tripolyphosphate (TPP) using ionic gelation method. The addition of TMAOH to CS enhanced the stability of MPs without affecting the particle size. FTIR analysis confirmed the structural changes whereas the FE-SEM analysis showed almost similar sizes of freeze–dried MPs as determined by Zetasizer. The morphology of the CS–TMAOH–TPP MPs was mostly similar to CS–TPP MPs. The Thermogravimetric analysis indicated that these MPs exhibit good thermal resistance. Moreover, the DSC and XRD analysis of the prepared MPs were conducted to analyze thermograms and crystallographic structure respectively. Overall, the present synthesized CS–TMAOH–TPP MPs are more stable than CS–TPP MPs, which will be useful for drug delivery applications.

The development of networks and web based environments combined with modern learning theories compose the new area of Learning Spaces aiming at enhancing interactive processes between educators, the Net generation's learners and the educational content. Collaboration at a distance (e-collaboration) supported by advanced learning technologies is today feasible and effective at a large scale opening up new perspectives in higher education. The paper presents a case study at the Hellenic Open University regarding the development of a learning sequence aimed at achieving high degrees of interactions among students, students and educators, and also at guiding them between face-to-face meetings when they prepare an essay. The Learning Space of the case study is realized by authoring sequences of learning activities using an LMS LAMS. Extending the case study, a methodology is illustrated to author collaborative sequences using LMS addressing to Open Universities in particular and also to conventional Universities in general.

This work reports details pertaining to the formation of chitosan nanoparticles that we prepare by the ionic gelation method. The molecular interactions of the ionic cross-linking of chitosan with tripolyphosphate have been investigated and elucidated by means of all-electron density functional theory. Solvent effects have been taken into account using implicit models. We have identified primary-interaction ionic cross-linking configurations that we define as H-link, T-link, and M-link, and we have quantified the corresponding interaction energies. H-links, which display high interaction energies and are also spatially broadly accessible, are the most probable cross-linking configurations. At close range, proton transfer has been identified, with maximum interaction energies ranging from 12.3 up to 68.3 kcal/mol depending on the protonation of the tripolyphosphate polyanion and the relative coordination of chitosan with tripolyphosphate. On the basis of our results for the linking types (interaction energies and torsion bias), we propose a simple mechanism for their impact on the chitosan/TPP nanoparticle formation process. We introduce the β ratio, which is derived from the commonly used α ratio but is more fundamental since it additionally takes into account structural details of the oligomers.

Nanoparticles based on poly(propylene succinate) copolymers with poly(ethyleneglycol) (PPSu-PEG) were prepared and evaluated in vitro for their potential for a more selective delivery of cisplatin to tumors using local hyperthermia. The copolymers were synthesized through one-pot melt-polymerization under vacuum. Their thermal properties were investigated using DSC. PPSu-PEG nanoparticles loaded with cisplatin were prepared by a double emulsion method. Their colloidal stability, drug release properties, and in vitro anticancer activity were assessed. The m.p. of the synthesized PPSu-PEG copolymers ranged between 40-45 °C. The PPSu-PEG nanoparticles were stable in aqueous media with high salt concentrations. The average size of the different compositions of the PPSu- PEG nanoparticles loaded with cisplatin ranged between 77 and 126 nm and all compositions exhibited low negative ζ-potential values. The PPSU-PEG/cisplatin nanoparticles released cisplatin much faster at 42 ° C than at 37 ° C and exhibited comparable to free cisplatin cytotoxicity against HT 29 cells, which was increased when the incubation temperature was increased from 37 ° C to 42 ° C. The results justify further investigation of the potential of PPSu-PEG copolymers for the development of temperature-sensitive, targetable cisplatin nanocarriers.

Platinized Cu, Ni, and Co deposits have been formed on glassy carbon (GC) electrode substrates by a two-step process, whereby a controlled amount of the transition metal was electrodeposited onto GC and subsequently partially exchanged for Pt upon immersion of the Cu/GC, Ni/GC, and Co/GC electrodes into a chloroplatinic acid solution. The spontaneous partial replacement of the transition metal by Pt resulted in Pt(Cu)/GC, Pt(Ni)/GC, and Pt(Co)/GC electrodes whose composition and depth profile were obtained by energy-dispersive spectrometry (EDS) and sputter-etch Auger electron spectroscopy (AES). Following electrochemical conditioning (involving electrode exposure to the oxygen and hydrogen evolution potential regimes), all deposits displayed typical Pt surface electrochemistry in acid solutions. Pt(Cu) catalysts exhibited enhanced electrocatalytic activity for methanol oxidation both during voltammetric and constant potential experiments. The behavior of Pt(Ni) and Pt(Co) depended on the method of assessment; in short-term voltammetric experiments, they were inferior to pure Pt, whereas in long-term constant potential experiments they outperformed it. The superior methanol oxidation activity of Pt(Cu) among all catalysts tested is interpreted in terms of the effect of Cu, Ni, and Co on methanol dissociative chemisorption and CO poison removal at/from the Pt surface.