Microfluidic devices fitted with “flowver” paper pumps generate steady,tunable gradients for extended observation of chemotactic cell migration

Microfluidics approaches have gained popularity in the field of directed cell migration, enabling control of the extracellular environment and integration with live-cell microscopy; however, technical hurdles remain. Among the challenges are the stability and predictability of the environment, which are especially critical for the observation of fibroblasts and other slow-moving cells. Such experiments require several hours and are typically plagued by the introduction of bubbles and other disturbances that naturally arise in standard microfluidics protocols. Here, we report on the development of a passive pumping strategy, driven by the high capillary pressure and evaporative capacity of paper, and its application to study fibroblast chemotaxis. The paper pumps—flowvers (flow + clover)—are inexpensive, compact, and scalable, and they allow nearly bubble-free operation, with a predictable volumetric flow rate on the order of μl/min, for several hours. To demonstrate the utility of this approach, we combined the flowver pumping strategy with a Y-junction microfluidic device to generate a chemoattractant gradient landscape that is both stable (6+ h) and predictable (by finite-element modeling calculations). Integrated with fluorescence microscopy, we were able to recapitulate previous, live-cell imaging studies of fibroblast chemotaxis to platelet derived growth factor (PDGF), with an order-of-magnitude gain in throughput. The increased throughput of single-cell analysis allowed us to more precisely define PDGF gradient conditions conducive for chemotaxis; we were also able to interpret how the orientation of signaling through the phosphoinositide 3-kinase pathway affects the cells’ sensing of and response to conducive gradients.     

Validation of a brief measure of teachers’ perceptions of school climate: relations to student achievement and suspensions

Based on theory and research on learning environments, the Delaware School Climate Survey–Teacher/Staff (DSCS–T/S) was developed to provide schools with a brief, psychometrically sound measure of teachers’ perceptions of school climate. Multigroup confirmatory factor analyses, conducted on a sample of 5,781 teachers, support staff, administrators and other staff in 132 schools, showed that a bifactor model consisting of seven specific factors best represented the data. Those factors were Teacher–Student Relations, Student–Student Relations, Teacher–Home Communication, Respect for Diversity, School Safety, Fairness of Rules, and Clarity of Expectations. Measurement invariance was found across grade levels (i.e., elementary, middle, and high schools) and subgroups of respondents (i.e., teachers, instructional support staff and noninstructional staff). As evidence of concurrent validity across grade levels, nearly all scores, aggregated at the school level and correlated significantly and negatively with suspensions/expulsion rates and positively with academic achievement. The DSCS–T/S is likely to be useful to schools interested in assessing school climate and the effects of various programs, such bullying prevention programs, that target the seven dimensions of school climate measured.     

Student peer assessment in evidence-based medicine (EBM) searching skills training: an experiment

Background:

Student peer assessment (SPA) has been used intermittently in medical education for more than four decades, particularly in connection with skills training. SPA generally has not been rigorously tested, so medical educators have limited evidence about SPA effectiveness.

Methods:

Experimental design: Seventy-one first-year medical students were stratified by previous test scores into problem-based learning tutorial groups, and then these assigned groups were randomized further into intervention and control groups. All students received evidence-based medicine (EBM) training. Only the intervention group members received SPA training, practice with assessment rubrics, and then application of anonymous SPA to assignments submitted by other members of the intervention group.

Results:

Students in the intervention group had higher mean scores on the formative test with a potential maximum score of 49 points than did students in the control group, 45.7 and 43.5, respectively (P = 0.06).

Conclusions:

SPA training and the application of these skills by the intervention group resulted in higher scores on formative tests compared to those in the control group, a difference approaching statistical significance. The extra effort expended by librarians, other personnel, and medical students must be factored into the decision to use SPA in any specific educational context.

Implications:

SPA has not been rigorously tested, particularly in medical education. Future, similarly rigorous studies could further validate use of SPA so that librarians can optimally make use of limited contact time for information skills training in medical school curricula.     

Impact of a full‐time integrated program on the achievement of nonhandicapped and mildly handicapped children

Abstract

We compared achievement gains of mildly handicapped and nonhandicapped third graders in a full‐time integrated program, Team Approach to Mastery (TAM), with gains of similar students in regular classrooms and resource‐room programs. Comparisons of residualized gain scores on the Comprehensive Test of Basic Skills showed that nonhandicapped students made substantially greater gains in full‐time integrated TAM classrooms than both mildly handicapped students in the same classrooms and nonhandicapped students in regular classrooms. Although mildly handicapped students in integrated TAM classrooms tended to experience greater gains than students in resource rooms, differences were significant only in math. Overall, results indicated the effectiveness of the TAM model, particularly when achievement gains of nonhandicapped and mildly handicapped students are contrasted with those reported in a more popular, and complex, integrated classroom model.     

Face fidelity: Perspectives from a local evaluation of the Safe Schools/Healthy Students initiative

The creation of a federal Safe Schools/Healthy Students (SS/HS) Initiative reflects a growing level of concern across the United States that many children do not feel safe at school, and that teachers must receive a new level of training to better equip themselves to manage a diverse student population. PROJECT BLUE was funded during the first phase of this initiative and proposed to provide students in its District with a range of services to improve school safety, decrease school violence, decrease alcohol and drug use, and improve student mental health. The local evaluation team collected information regarding project implementation and its impact on school safety, school climate, and teacher preparedness to manage student misbehavior. Selected results are highlighted in the article. However, the primary purpose of this article is to document lessons learned from the evaluation of this project. Lessons learned are presented in four areas: leadership, communication, system change efforts, and local evaluation of federal initiatives. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 515–529, 2003.     

Development of orthographic skills in Chinese children

This study investigates possible developmental trends in children's invented spelling (or spelling errors) in Chinese elementary schools. The entire study consists of two substudies, Study A and Study B. Study A analyzes over 7000 invented spellings collected from the writing samples of 1200 children. Study B analyzes 3995 invented spellings that were collected from the spelling tests of 300 children. These invented spellings are sorted initially according to emerging patterns according to the way the invented spellings deviate from standard spellings; they are then further subsumed into three general categories according to the linguistic principles of Chinese characters - phonologically based spelling errors, graphemic spelling errors, and semantic spelling errors. Qualitative analysis of the invented spellings of these three categories indicates that children's spelling errors are not random; rather they reflect the development of children's orthographic knowledge. Regression analysis for linear trend shows that a developmental trend in the use of spelling strategies exists: at the lower elementary level, phonological strategies predominate; as grade level advances, the use of graphemic and semantic strategies increases.     

Ground-plane influence on airplane wings

The present study discloses a very material ground-plane influence at small incidence and ground gap. The lift is augmented, the drag diminished; the lift-drag may be increased 30 to 40 per cent. Thus a sea gull or a suitably designed monoplane may skim the surface of smooth water with considerably greater economy than it can fly at a few wing depths aloft. But the pitching moment is only slightly affected by the presence of a ground plane.