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The influence of heuristical strategies upon the level of two experimental classes is studied in this paper. The didactic experiment took place at secondary school in Cluj-Napoca, in 2008-2009 school year. The study theme "The Unsaturated Hydrocarbons--Alkenes" has been efficiently learned by using the most active methods: laboratory experiment, brain storming, modeling, problematization. The results obtained in the research demonstrate the efficiency of interactive methods in teaching-learning process.

A series of aspects regarding the aria of teaching sciences (chemistry, biology, physics, geography) in pre-universitary learning is presented. This paper underlines the importance of prerepresentations of students in teaching-learning process in pre-universitary learning, assuring in this way a desirable direction of the reform in pre-universitary learning: so that the student becomes its own self-improvement agent. The characteristics of the reform in pre-universitary learning in our country are revealed, in European context (Naumescu, A., Pasca R. D., 2008).

Some up-to-date problems in science education in European context are treated in this paper. The characteristics of science education across Europe are presented. Science teachers' general competencies are underlined. An example of problem-solving as teaching method in chemistry is studied in knowledge based society. Transforming teacher practice across the Europe is a long-term project and will require significant investment in continuous professional development. Better science teaching is grounded, first of all, in improving the quality of teacher preparation and in making continuing professional education available for science teacher.

This work presents an innovative procedure to fabricate collagen (COLL) structures with controlled porosity using Langmuir technique of building the self-assembled collagen structures, alone or in the presence of the cross linker APTES [(3-aminopropyl) triethoxy silane], at the interface between air and aqueous saline subphase. Then, at selected surface pressures, the COLL structures were transferred from the interface on solid substrate (glass or mica) by Langmuir-Blodgett (LB) technique, finally obtaining porous COLL scaffolds. The morphology and porosity of COLL scaffolds were characterized by atomic force microscopy (AFM). The porous COLL structures are densified progressively at higher silane concentrations and/or at higher surface pressures. Collagen scaffolds have high potential for use in bone regeneration and tissue engineering. [ABSTRACT FROM AUTHOR]

Collagen mineralization (CM) is a challenging process that has received a lot of attention in the past years. Among the reasons for this interest, the key role is the importance of collagen and hydroxyapatite in natural bone, as major constituents. Different protocols of mineralization have been developed, specially using simulated body fluid (SBF) and many methods have been used to characterize the systems obtained, starting with methods of determining the mineral content (XRD, FTIR, Raman, High-Resolution Spectral Ultrasound Imaging), continuing with imaging methods (AFM, TEM, SEM, Fluorescence Microscopy), thermal analysis (DSC and TGA), evaluation of the mechanical and biological properties, including statistical methods and molecular modeling. In spite of the great number of studies regarding collagen mineralization, its mechanism, both in vivo and in vitro, is not completely understood. Some of the methods used in vitro and investigation methods are reviewed here. [ABSTRACT FROM AUTHOR]

Self assemblies of mixed cholesterol (CHO) and dimyristoyl phosphatidyl choline (DMPC) monolayers spread at the air/water interface were prepared and investigated by compression isotherms using Langmuir technique (LT). By means of the Langmuir-Blodgett technique (LBT), these self assemblies were transferred on solid support (e.g. glass optically polished) and were characterized by atomic force microscopy (AFM) imaging technique. This investigation demonstrates that rather strong interactions between these lipid molecules, DMPC and CHO molecules, lead to well defined two-dimensional stable nanostructures characterized by low surface roughness. These lipid self assemblies could have practical applications for biosensors fabrication. They also occur within natural membranes representing the lipid matrix where in vivo the protein molecules are embedded or adsorbed. [ABSTRACT FROM AUTHOR]

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