Three-dimensional printed millifluidic devices for zebrafish embryo tests

Implementations of Lab-on-a-Chip technologies for in-situ analysis of small model organisms and embryos (both invertebrate and vertebrate) are attracting an increasing interest. A significant hurdle to widespread applications of microfluidic and millifluidic devices for in-situ analysis of small model organisms is the access to expensive clean room facilities and complex microfabrication technologies. Furthermore, these resources require significant investments and engineering know-how. For example, poly(dimethylsiloxane) soft lithography is still largely unattainable to the gross majority of biomedical laboratories willing to pursue development of chip-based platforms. They often turn instead to readily available but inferior classical solutions. We refer to this phenomenon as workshop-to-bench gap of bioengineering science. To tackle the above issues, we examined the capabilities of commercially available Multi-Jet Modelling (MJM) and Stereolithography (SLA) systems for low volume fabrication of optical-grade millifluidic devices designed for culture and biotests performed on millimetre-sized specimens such as zebrafish embryos. The selected 3D printing technologies spanned a range from affordable personal desktop systems to high-end professional printers. The main motivation of our work was to pave the way for off-the-shelf and user-friendly 3D printing methods in order to rapidly and inexpensively build optical-grade millifluidic devices for customized studies on small model organisms. Compared with other rapid prototyping technologies such as soft lithography and infrared laser micromachining in poly(methyl methacrylate), we demonstrate that selected SLA technologies can achieve user-friendly and rapid production of prototypes, superior feature reproduction quality, and comparable levels of optical transparency. A caution need to be, however, exercised as majority of tested SLA and MJM resins were found toxic and caused significant developmental abnormalities in zebrafish embryos. Taken together, our data demonstrate that SLA technologies can be used for rapid and accurate production of devices for biomedical research. However, polymer biotoxicity needs to be carefully evaluated.     

Academic self-concept and teachers' perceptions of normal,mentally retarded,and learning disabled elementary students

The self-concepts of educable mentally impaired, learning disabled, and nonhandicapped children were assessed using the Student Self-Evaluation (SSE), Teacher Evaluation Scale (TES), and How I See Myself (HISM) test. A Groups × Age × Sex analysis of covariance, with IQ effects statistically controlled, was computed for each measure. On the SSE, the groups were significantly different, with nonhandicapped students having better self-concepts than learning disabled students, and learning disabled students having better self-concepts than educable mentally impaired students. Teacher estimates of self-concept (TES) indicated that nonhandicapped students have better self-concepts than have handicapped students. For the HISM scores, there was a Group × Sex interaction, but no significant main effects; there was no consistent pattern to the interactions. The results suggest that handicapped children, as a group, have a lower self-concept than have nonhandicapped children. Implications for educational programming and future research are offered.     

Dietary supplements during pregnancy

In this column, the author addresses the use of dietary supplements and prenatal vitamins during pregnancy.     

Archives as networks: the geography of record-keeping in the Society of Jesus (1540–1773)

This paper examines the archives of a major Catholic order, the Society of Jesus. The quality and amount of Jesuit sources allows a very detailed reconstruction not only of how the archives were meant to function, but also of how they were used in daily life. While the Jesuits and their archives resemble many other early modern institutions, the wealth of documentation nevertheless makes them particularly suitable for a case study of early modern archival practice. The paper argues that the order consciously developed a network of archives that closely mirrored the institutional framework of the Jesuit bureaucracy. Ideally, smooth and swift movement of papers within this network was meant to provide easy access to relevant documents for users at all hierarchical levels. In reality, however, Jesuit record keeping remained far from this ideal. Papers were misplaced or simply got lost in the maze of archives.     

Differential-outcomes effect using hedonically nondifferential outcomes with delayed matching to sample by pigeons

When differential outcomes follow correct responses to each of two comparison stimuli in matching to sample, relative to the appropriate control condition, higher matching accuracy is typically found, especially when there is a delay between the sample and the comparison stimuli. In two experiments, we examined whether this differential-outcomes effect depends on using outcomes that differ in hedonic value (e.g., food vs. water). In Experiment 1, we found facilitated retention when a blue houselight followed correct responses to one comparison stimulus and a white houselight followed correct responses to the other, prior to nondifferential presentations of food. In Experiment 2, we found facilitated retention again when a blue houselight followed correct responses to one comparison stimulus and a tone followed correct responses to the other, prior to nondifferential presentations of food. The results of both experiments indicate that the differential-outcomes effect does not depend on a difference in hedonic value of the differential outcomes, and they suggest that outcome anticipations consisting of relatively arbitrary but differential stimulus representations can serve as cues for comparison choice.