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We wanted to assess the impact of learning-centered methodology on learning strategies and learning approaches of a students' group of Chemistry. They were first year engineering students from the Polytechnic University of Valencia. We used a pre-experimental design with pretest and posttest measures by means of the CEVEAPEU and CPE questionnaires. The sample consisted of 20 students. The teaching methods included expositive methodology, questions, problem solving, development of a monograph, presentations, laboratory practices, team work, tutoring in the classroom and an evaluation system that made use of training procedures that returned feedback to students (two diagnostic tests, assessment of solved problems, self-assessment using the e-learning platform of the university, oral assessment in class, written tests, etc..). Significant improvements in learning strategies scores in the posttest and increasing in deep approach were found. [ABSTRACT FROM AUTHOR]

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A thorough mechanistic study has been performed on the reaction between benzophenone (BZP) and a series of 1,4-dienes, including 1,4-cyclohexadiene (CHD), 1,4-dihydro-2-methylbenzoic acid (MBA), 1,4-dihydro-1,2-dimethylbenzoic acid (DMBA) and linoleic acid (LA). A combination of steady-state photolysis, laser flash photolysis (LFP), and photochemically induced dynamic nuclear polarization (photo-CIDNP) have been used. Irradiation of BZP and CHD led to a cross-coupled sensitizer-diene product, together with 6, 7, and 8. With MBA and DMBA as hydrogen donors, photoproducts arising from cross-coupling of sensitizer and diene radicals were found; compound 7 was also obtained, but 6 and o-toluic acid were only isolated in the irradiation of BZP with MBA. Triplet lifetimes were determined in the absence and in the presence of several diene concentrations. All three model compounds showed similar reactivity (k(q) ≈10(8)  M(-1)  s(-1)) towards triplet excited BZP. Partly reversible hydrogen abstraction of the allylic hydrogen atoms of CHD, MBA, and DMBA was also detected by photo-CIDNP on different timescales. Polarizations of the diamagnetic products were in full agreement with the results derived from LFP. Finally, LA also underwent partly reversible hydrogen abstraction during photoreaction with BZP. Subsequent hydrogen transfer between primary radicals led to conjugated derivatives of LA. The unpaired electron spin population in linoleyl radical (LA(.)) was predominantly found on H(1-5) protons. To date, LA-related radicals were only reported upon hydrogen transfer from highly substituted model compounds by steady-state EPR spectroscopy. Herein, we have experimentally established the formation of LA(.) and shown that it converts into two dominating conjugated isomers on the millisecond timescale. Such processes are at the basis of alterations of membrane structures caused by oxidative stress., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)