Homogeneous Tubular‐Flow Process for Monoolein Preparation

Esterification of fatty acids with glycerol is characterized by negligible solubility of the two liquid phases. The reactions to mono‐, di‐ and triglycerides taking place in the fatty acid phase, are limited by chemical equilibrium. The scope of this study is to investigate in a tubular reactor the conversion of a homogeneous mixture of oleic acid and glycerol in tert‐butanol. The liquid composition in this study was 1 mol of oleic acid, 6 mol of glycerol and 14 mol of tert‐butanol. Experiments were conducted in a tubular reactor at 35 atm over a temperature range of 200–240 °C and residence times of 0.7–17.6 h to determine the kinetics and the chemical equilibrium. The selectivity to monoolein was >95 mol %. A reversible second order reaction fits the data well.     

Total Synthesis of (−)‐Doliculide,Structure–Activity Relationship Studies and Its Binding to F‐Actin

Actin, an abundant protein in most eukaryotic cells, is one of the targets in cancer research. Recently, a great deal of attention has been paid to the synthesis and function of actin‐targeting compounds and their use as effective molecular probes in chemical biology. In this study, we have developed an efficient synthesis of (?)‐doliculide, a very potent actin binder with a higher cell‐membrane permeability than phalloidin. Actin polymerization assays with (?)‐doliculide and two analogues on HeLa and BSC‐1 cells, together with a prediction of their binding mode to F‐actin by unbiased computational docking, show that doliculide stabilizes F‐actin in a similar way to jasplakinolide and chondramide C.     

Analytical modeling of the white-light fringe

An analytical technique for extracting phase, visibility, and amplitude information as needed for interferometric astrometry for the Space Interferometry Mission (SIM) is presented. This model accounts for a number of physical and instrumental effects and is valid for the general case of a bandpass filter. I was able to obtain a general solution for polychromatic phasors and to address the properties of unbiased fringe estimators in the presence of noise. For demonstration purposes I studied a rectangular bandpass filter with two different methods of optical path difference (OPD) modulation: stepping and ramping OPD modulation. A number of areas for further studies relevant to instrument design and simulations are outlined and discussed.     

Measuring Knowledge to Optimize Cognitive Load Factors During Instruction.

The expertise reversal effect occurs when a learning procedure that is effective for novices becomes ineffective for more knowledgeable learners. The authors consider how to match instructional presentations to levels of learner knowledge. Experiments 1-2 were designed to develop a schema-based rapid method of measuring learners' knowledge in a specific area. Experimental data using algebra and geometry materials for students in Grades 9-10 indicated a highly significant correlation (up to .92) between performance on the rapid measure and traditional measures of knowledge, with test times reduced by factors of 4.9 and 2.5, respectively. Experiments 3-4 used this method to monitor learners' cognitive performance to determine which instructional design should be used for given levels of expertise. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incorporating learner experience into the design of multimedia instruction.

In Experiment 1, inexperienced trade apprentices were presented with one of four alternative instructional designs: a diagram with visual text, a diagram with auditory text, a diagram with both visual and auditory text, or the diagram only. An auditory presentation of text proved superior to a visual-only presentation but not when the text was presented in both auditory and visual forms. The diagram-only format was the least intelligible to inexperienced learners. When participants became more experienced in the domain after two specifically designed training sessions, the advantage of a visual diagram-auditory text format disappeared. In Experiment 2, the diagram-only group was compared with the audio-text group after an additional training session. The results were the reverse of those of Experiment 1: The diagram-only group outperformed the audio–text group. Suggestions are made for multimedia instruction that takes learner experience into consideration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative effectiveness of animated and static diagrams: An effect of learner prior knowledge

This paper investigates the relationship between instructional effectiveness of animated vs. static diagrams and levels of learner expertise in the task domain of transforming graphs of simple linear and quadratic functions. It was demonstrated on many occasions that instructional formats that are effective for low-knowledge learners could be ineffective, or even deleterious, for high-knowledge learners, and vice versa (the expertise reversal effect). The levels of learner (university students) expertise in this study were measured using an online rapid diagnostic method, a rapid verification technique, that involves presenting learners with a series of possible solution steps reflecting various stages of the solution procedure and asking them to rapidly verify the suggested steps. The results indicated a significant interaction between levels of learner expertise and instructional formats. Novice learners benefited more from static diagrams than from animated diagrams, while more knowledgeable learners benefited more from animated rather than static diagrams. A theoretical explanation of the effect is suggested within the framework of cognitive load theory.