and his colleagues Remmers and Brandenburg 1927). Centra (1993) divided the body of work on student evaluation of college teaching (SET) into the following four historical time frames:1. 1927-60 was dominated by the work of Remmers and his colleagues at Purdue University who developed the Purdue Rating Scale for Instructors and conducted early psychometric analyses to support what was, at the time, quite an innovative method of evaluation (Remmers 1927).2. During the 1960s, the use of student evaluations was almost entirely voluntary.3. The 1970s were considered the "golden age of research" on student evaluations and extended the earlier work to demonstrate the validity and utility of student ratings for both formative and summative purposes. 134 COLLEGE TEACHING T Downloaded by [Nova Southeastern University] at 23:15 27 December 2014 Vol. 52/No. 4 Further research on contextual variables and SETs: What do written comments reveal about the SETs? Do students comment on factors that are out of control of the instructor (e.g., climate of the room, time of class meeting, technical problems, etc.)? Downloaded by [Nova Southeastern University] at 23:15 27 December 2014

The glass transition temperature (T g ) of a series of polyacrylate-and polymethacrylate-based polymers having bistable hydrazone photoswitches as pendants increases upon photoisomerization. The ensuing photohardening of the polymeric network was corroborated using nanoindentation measurements. The bistability of the switch allowed us to lock-in and sustain multiple T g values in the same polymeric material as a function of the hydrazone switch's Z/E isomer ratio, even at elevated temperatures.

No abstract

Gadolinium doped ceria is a well-known oxygen ion conduction material for solid fuel cell electrolytes. With its centrosymmetric average lattice and relatively low bulk dielectric constant it does not look interesting for electromechanical applications. However, a giant electrostriction (ES) effect was recently found in Ce 0.8 Gd 0.2 O 2−x thin films. It was explained by the dynamic response of oxygen vacancies to an external electric field. In this work, the giant ES response has been reproduced in sputter deposited thin films. The proper transverse bulk ES coefficient has been derived from the measured clamped value. For this purpose, the Young's modulus was measured by nanoindentation. The highest ES coefficient was found as 9.0×10 −19 (m/V) 2 for the strain coefficient, and 2.3×10 −7 N/V 2 for the effective stress coefficient. Specific growth conditions must be chosen in order to obtain a microstructure exhibiting the giant ES effect. There is evidence for a higher oxygen deficiency than needed to compensate the gadolinium dopants (Gd'). It was observed that the nature of the bottom electrode impacts on the size of the effect. The highest response was obtained at films grown on Al bottom electrodes. To learn more on the mechanisms of the giant ES effect, a bipolar cycling was performed to test the delay time for the ionic reorientation in changing the sign of polarization, as observed in the stress loop. The maximal response was observed below 100Hz in this bipolar mode, showing that the time for 180 • reorientation amounts to several milliseconds.

Circulating nucleic acids,s uch as short interfering RNA( siRNA), regulate many biological processes;h owever, the mechanism by whichthese molecules enter the cell is poorly understood. The role of extracellular-matrix-derived polymers in binding siRNAs and trafficking them across the plasma membrane is reported. Thermal melting, dynamic light scattering, scanning electron microscopy, and computational analysis indicate that hyaluronic acid can stabilizesiRNAvia hydrogen bonding and Vand er Waals interactions.T his stabilization facilitated HA size-and concentration-dependent gene silencing in aCD44-positive human osteosarcoma cell line (MG-63) and in human mesenchymal stromal cells (hMSCs). This native HA-based siRNAtransfection represents the first report on an anionic,n on-viral delivery method that resulted in approximately 60 %gene knockdowninboth cell types tested, which correlated with ar eduction in translation levels.