High-throughput size-based rare cell enrichment using microscale vortices

Cell isolation in designated regions or from heterogeneous samples is often required for many microfluidic cell-based assays. However, current techniques have either limited throughput or are incapable of viable off-chip collection. We present an innovative approach, allowing high-throughput and label-free cell isolation and enrichment from heterogeneous solution using cell size as a biomarker. The approach utilizes the irreversible migration of particles into microscale vortices, developed in parallel expansion-contraction trapping reservoirs, as the cell isolation mechanism. We empirically determined the critical particle∕cell diameter D(crt) and the operational flow rate above which trapping of cells∕particles in microvortices is initiated. Using this approach we successfully separated larger cancer cells spiked in blood from the smaller blood cells with processing rates as high as 7.5×10(6) cells∕s. Viable long-term culture was established using cells collected off-chip, suggesting that the proposed technique would be useful for clinical and research applications in which in vitro culture is often desired. The presented technology improves on current technology by enriching cells based on size without clogging mechanical filters, employing only a simple single-layered microfluidic device and processing cell solutions at the ml∕min scale.     

Effects of optimal pacing strategies for 400-, 800-, and 1500-m races on the VO2 response

The aim of this study was to compare the evolution of oxygen uptake (VO2) in specifically trained runners during running tests based on the 400-, 800-, and 1500-m pacing strategies adopted by elite runners to optimize performance. Final velocity decreased significantly for all three distances, with the slowest velocity in the last 100 m expressed relative to the peak velocity observed in the 400 m (77%), 800 m (88%), and 1500 m (96%). Relative to the previously determined VO2max values, the respective VO 2peak corresponded to 94% (400 m) and 100% (800 and 1500 m). In the last 100 m, a decrease in VO2 was observed in all participants for the 400-m (15.6 ± 6.5%) and 800-m races (9.9 ± 6.3%), whereas a non-systematic decrease (3.6 ± 7.6%) was noted for the 1500 m. The amplitude of this decrease was correlated with the reduction in tidal volume recorded during the last 100 m of each distance (r = 0.85, P < 0.0001) and with maximal blood lactate concentrations after the three races (r = 0.55, P < 0.005). The present data demonstrate that the 800 m is similar to the 400 m in terms of decreases in velocity and VO2.     

Instructor-provided summary infographics to support online learning

Infographics are a visualisation tool that can be used to improve retention, comprehension and appeal of complex concepts. The rise of infographic use in education has facilitated new forms of application and design of these tools. Instructor-provided summary infographics are a new form of infographic, whereby key learning objectives and content are summarised in graphical form at the end of a lesson. However, it is unknown whether these types of infographics can support learning in online environments. This exploratory research investigates student perceptions, retention, applications and activity generation of instructor-provided summary infographics in a massive online learning environment. Using both post-course learner survey data (n = 1,899) and text mining analysis (n = 72,490 words), results present how learners perceived instructor-provided summary infographics as useful and appealing for retaining, clarifying and understanding learning concepts. The research contributes a novel understanding of summary infographics in online learning environments, and supports their use as a design tool for educational delivery in the online space.     

Science student role: Evidence of social structural norms specific to school science

Sociocultural studies of science education have consistently recognized the dialectic nature of students' agency to create and author positions for themselves and the structural constraints that may influence them. This mixed‐methods study explores one particular aspect of these potential constraints: the possibility of a social structure specific to school science, using the concept of a science student role as an indicator. The first phase of the study was qualitative and exploratory, using open‐ended questionnaires and interviews to understand students' views of the expectations placed on them as science students (n = 95). The second phase was quantitative (using items developed from the qualitative analysis), with both exploratory and confirmatory elements (n = 157). Results suggest clear and explicit role understandings among these students, characterized by references to expectations of intelligence, experimental skill, scientific mindedness, and appropriate classroom behavior. The consistency of these expectations across genders, science teachers and schools provides evidence that there is an element of social structure specific to school science that needs to be considered in studies of student agency and identity. © 2010 Wiley Periodicals, Inc., Inc. J Res Sci Teach 48: 367–395, 2011     

Shifting definitions of emotional maltreatment: an analysis child welfare investigation laws and practices in Canada

Objective

Although there is growing evidence that the emotional dimensions of child maltreatment are particularly damaging, the feasibility and appropriateness of including emotional maltreatment (EM) in child welfare statutes continues to be questioned. Unlike physical and sexual abuse where investigations focus on discreet incidents of maltreatment, EM is not as easily defined and delimited. Through a review of legislation and child welfare investigation practices in Canada, this paper examines (1) whether Canadian child welfare services respond to EM with the same level of perseverance as with other forms of maltreatment and (2) the extent to which the introduction in 2008 of a more specific EM taxonomy distinguishes between EM and family problems that could lead to EM.

Method

Following an analysis of the legislative framework for EM across Canada, investigations practices in Canada are examined using data from the 1998, 2003 and 2008 cycles of the Canadian Incidence Study of Reported Child Abuse and Neglect (CIS). Using data from the 2008 cycle, EM investigations are compared to other maltreatment investigations for all of Canada (N = 15,980). Changes in EM investigations over time are then compared using data from the three cycles of the study, excluding Québec because of limited data availability in 2003 (N = 5,360 in 1998, 11,562 in 2003 and 14,050 in 2008).

Results

EM is included as a form of reportable maltreatment in all provincial and territorial statutes in Canada. Over 11,000 cases of EM were substantiated in Canada in 2008, at a rate of 1.86 cases per 1,000 children. While EM investigations were substantiated at a lower rate as other forms of maltreatment, a higher proportion of EM cases were referred for specialized services, kept open for on-going child welfare services, lead to an out of home placement, and lead to an application to child welfare court. Using a broad definition of EM the number of investigations classified as EM in Canada, excluding Québec, nearly tripled from 1998 to 2003. In 2008, using more specific definitions focusing on caregiver definitions, the number of investigations classified as EM nearly returned to their 1998 level, with nearly twice as many cases being classified as risk of future maltreatment.

Conclusion

EM is a well established category for child welfare intervention in Canada, however, more emphasis should be given to distinguishing between EM and family problems that place children at risk of EM.     

Family and Sociodemographic Predictors of School Readiness Among African American Boys in Kindergarten

Research Findings: Data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998–1999, were used to examine the relation between parenting, sociodemographic characteristics, and school readiness among (N = 1,136) African American boys in kindergarten. Parenting was defined as parenting style (i.e., warmth and control), home learning stimulation, and culturally relevant parenting. Two child outcomes previously linked to school readiness were examined: kindergarten reading and approaches to learning. Hierarchical regression analyses were performed to address 2 research questions. First, does parenting predict kindergarten reading above and beyond the contribution of sociodemographic characteristics? Second, does parenting predict kindergarten approaches to learning above and beyond the contribution of sociodemographic characteristics? Practice or Policy: Children with parents who set consistent bedtimes, provided more books in their homes, and read to them more frequently had better kindergarten reading scores after socioeconomic status, environmental safety, and maternal education were controlled. Similarly, children with parents who provided more books in their home and read to their children more frequently had more positive teacher-rated approaches to learning scores in kindergarten. Implications for future research are discussed.     

Doctoral women: managing emotions,managing doctoral studies

This paper explores the experiences of women doctoral students and the role of emotion during doctoral candidature. The paper draws on the concept of emotional labour to examine the two sites of emotional investment students experienced and managed during their studies: writing and family relationships. Emotion is perceived by many dominant stakeholders as soft, subjective and an impediment to acquiring objective knowledge. The importance of emotion is under recognised. When it is discussed, the role of emotion in the doctoral undertaking is often subsumed in the passionless language of bureaucratic rationalisation and economic imperatives. This paper builds on a growing literature that examines students' emotions and doctoral candidature. It draws on the experiences of women undertaking their doctoral studies at a large metropolitan university in Sydney, Australia, to show first, how emotional labouring can enable students to channel emotions towards productive behaviours that can contribute to successful doctoral candidature, and second, that studies that attend to emotion offer more nuanced insights into students' experiences during the doctoral undertaking.     

Investigating Patterns of Participation and Conversation Content in an Online Mentoring Program for Northern Canadian Youth

In this study, we describe participant characteristics, conversation content, and program success of an online mentoring program for northern Canadian youth. We investigate the associations between demographics and program success. The profiles and conversations of students and mentors that participated in the program between 2009 and 2013 were analyzed. Students were categorized into two groups (high and low engagement) based on the number of words written to their mentors. The high group contained proportionally more urban than rural students and equal proportions of Aboriginal and non-Aboriginal students, while the low group contained equal numbers of rural and urban students and proportionally more Aboriginal than non-Aboriginal students. This study provides valuable information on the use of online mentoring in northern communities.     

Theory of mind,executive function and social competence in boys with ADHD

Abstract

Twenty-two boys with a diagnosis of ADHD were com-KEYWORDS pared with 22 typically developing boys on an advanced theory of mind task and on two tasks measuring aspects of executive function. Parents completed rating forms measuring general social competence, as well as mentalizing and non-mentalizing social behaviours. There were no differences between the groups on the advanced theory of mind measure.The children with ADHD scored more poorly than controls on an inhibition task but not on a planning task once age and IQ had been covaried. Ratings of social competence were correlated with theory of mind and executive function ability for the typically developing controls but not for the children with ADHD. The results are discussed in terms of inhibitory and social information processing accounts of ADHD.