In Their Own Voices: Assessing Student Learning Through Analysis of Reflective Writing

In order to assess students\u27 experiences of their service-learning Capstone, researchers used a qualitative design to study 50 students\u27 reflections from seven distinctly different Senior Capstone courses. In these reflections, students demonstrated integrative learning while deepening their understanding of communication, critical thinking, diversity, and social responsibility

Transfer Hydrogenation Reactions Catalysed by Free or Silica-immobilized Complexes [RuCl2(ampy)(RN(CH2PPh2)2)]

5The complexes cis-[RuCl2(ampy){(RN)-N-1(CH2PPh2)(2)}] [ampy = (2-aminomethyl)pyridine, R-1 = C6H5 or (CH3CH2O)(3)Si-(CH2)(3)] showed very high catalytic activity in the homogeneous transfer hydrogenation of acetophenone (TOF > 300000 h(-1)) with the use of 2-propanol as the hydrogen donor and in the presence of sodium isopropoxide. The ligand (CH3CH2O)(3)Si(CH2)(3)N(CH2PPh2)(2) (ATM) was prepared in high yield by reacting (3-aminopropyl)triethoxysilane, paraformaldehyde, and diphenylphosphane in toluene heated at 80 degrees C. The -N(CH2PPh2)(2) function was attached to the surface of three different kinds of silica by means of two alternative methods. Thus, MA-Si-150 and mesoporous MA-Si-MCM-41 were prepared by the reaction of the inorganic matrix with ATM, whereas MA-Si-60 was synthesized by reaction of the commercially available 3-aminopropyl-functionalized silica gel with HCHO and PHPh2 in refluxing toluene. The -(CH2)(3)N(CH2PPh2)(2) functionalized inorganic materials were used to anchor the RuCl2(ampy) moiety; thus, three different silica-immobilized versions of the cis-[RuCl2(ampy)-(ATM)] complex were obtained. The silica-anchored complexes were tested in the transfer hydrogenation of acetophenone, which was found to be fast and quantitative; the effect of the nature of the silica support on the activity of the catalyst was almost negligible. It was possible to reuse the catalytic system for a second cycle without a decrease in the activity, but the efficiency of the catalyst considerably diminished in successive reuses.reservedmixedDEL ZOTTO A; GRECO C; BARATTA W; SIEGA K; RIGO PDEL ZOTTO, Alessandro; Greco, C; Baratta, Walter; Siega, K; Rigo, Pierluig

Design of a Genetic Algorithm for the Simulated Evolution of a Library of Asymmetric Transfer Hydrogenation Catalysts.

A library of catalysts was designed for asymmetric-hydrogen transfer to acetophenone. At first, the whole library was submitted to evaluation using high-throughput experiments (HTE). The catalysts were listed in ascending order, with respect to their performance, and best catalysts were identified. In the second step, various simulated evolution experiments, based on a genetic algorithm, were applied to this library. A small part of the library, called the mother generation (G0), thus evolved from generation to generation. The goal was to use our collection of HTE data to adjust the parameters of the genetic algorithm, in order to obtain a maximum of the best catalysts within a minimal number of generations. It was namely found that simulated evolution's results depended on the selection of G0 and that a random G0 should be preferred. We also demonstrated that it was possible to get 5 to 6 of the ten best catalysts while investigating only 10 % of the library. Moreover, we developed a double algorithm making this result still achievable if the evolution started with one of the worst G0