Many-Body Terms in van der Waals Cohesion Energy of Nanotubes

We have developed a model for the calculation of van der Waals force for layered systems with axial symmetry. Our result can be applied to compute the cohesion of a carbon nanotube to a substrate, the cohesion between nanotubes, and between shells of multiwall nanotubes. We have obtained unusal power laws for the distance dependence of the many-body van der Waals potential.     

When less is more in cognitive diagnosis: A rapid online method for diagnosing learner task-specific expertise.

Rapid cognitive diagnosis allows measuring current levels of learner domain-specific knowledge in online learning environments. Such measures are required for individualizing instructional support in real time, as students progress through a learning session. This article describes 2 experiments designed to validate a rapid online diagnostic method that was inspired by experimental procedures applied in classical cognitive studies of chess expertise. With the described rapid verification method, learners are required to rapidly verify suggested steps at various stages of a problem solution procedure. In this study involving 33 university students, a high degree of correlation was found between rapid testing scores and results of in-depth cognitive diagnosis based on observations of problem-solving steps using video recordings and concurrent verbal reports in the domains of kinematics (vector addition motion problems) and mathematics (transforming graphs of linear and quadratic functions). The article discusses possible applications of the suggested method in adaptive learning environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tetrahydroisoquinolines: New Inhibitors of Neutrophil Extracellular Trap (NET) Formation

Neutrophils are short‐lived leukocytes that migrate to sites of infection as part of the acute immune response, where they phagocytose, degranulate, and form neutrophil extracellular traps (NETs). During NET formation, the nuclear lobules of neutrophils disappear and the chromatin expands and, accessorized with neutrophilic granule proteins, is expelled. NETs can be pathogenic in, for example, sepsis, cancer, and autoimmune and cardiovascular diseases. Therefore, the identification of inhibitors of NET formation is of great interest. Screening of a focused library of natural‐product‐inspired compounds by using a previously validated phenotypic NET assay identified a group of tetrahydroisoquinolines as new NET formation inhibitors. This compound class opens up new avenues for the study of cellular death through NET formation (NETosis) at different stages, and might inspire new medicinal chemistry programs aimed at NET‐dependent diseases.     

Instructional designs for the development of transferable knowledge and skills: A cognitive load perspective

This paper analyzes the main points and results of a set of the previous papers in this Special Issue from the point of view of developing characteristics of flexible—transferable—expertise. It focuses on cognitive load issues related to the acquisition of deep transferable knowledge structures and developing metacognitive and self-regulation skills. The contributions to this Special Issue demonstrate that appropriate instructional support and optimal levels of control over the learning processes, enhanced by self-explanation and self-visualization techniques, may enhance learners’ abilities to transfer their knowledge and skills. Better understanding of the role of germane cognitive load, as well as our abilities to measure different types of load and high-level cognitive processes are essential for further progress in this area.     

Enantioselective Organocatalytic Synthesis of a Secoyohimbane‐Inspired Compound Collection with Neuritogenic Activity

Natural products provide evolutionary validated core structures to inspire the synthesis of new compound collections endowed with neurite growth‐promoting activity. Rhynchophylline is the major component of Uncaria species, and has been used to treat neurological diseases in Chinese traditional medicine. Based on the structure of this spirocyclic secoyohimbane alkaloid, we developed a highly enantioselective and efficient organocatalyzed synthesis method to provide a tetracyclic secoyohimbane scaffold incorporating a quaternary and three tertiary stereogenic centers, in a one‐pot multistep reaction sequence. A compound collection of derived secoyohimbanes was synthesized and expanded by decorating the periphery of the basic scaffold with additional substituents to increase the diversity. Evaluation of the different subcollections of secoyohimbanes for modulation of neurite outgrowth in the SH‐SY5Y human cell line led to the discovery of new compounds that promote neurite outgrowth.     

When redundant on-screen text in multimedia technical instruction can interfere with learning

It is frequently assumed that presenting the same material in written and spoken form benefits learning and understanding. The present work provides a theoretical justification based on cognitive load theory, and empirical evidence based on controlled experiments, that this assumption can be incorrect. From a theoretical perspective, it is suggested that if learners are required to coordinate and simultaneously process redundant material such as written and spoken text, an excessive working memory load is generated. Three experiments involving a group of 25 technical apprentices compared the effects of simultaneously presenting the same written and auditory textual information as opposed to either temporally separating the two modes or eliminating one of the modes. The first two experiments demonstrated that nonconcurrent presentation of auditory and visual explanations of a diagram proved superior, in terms of ratings of mental load and test scores, to a concurrent presentation of the same explanations when instruction time was constrained. The 3rd experiment demonstrated that a concurrent presentation of identical auditory and visual technical text (without the presence of diagrams) was significantly less efficient in comparison with an auditory-only text. Actual or potential applications of this research include the design and evaluation of multimedia instructional systems and audiovisual displays.