Microfluidic chip for fast bioassays��evaluation of binding parameters     

Jakub ?těpánek  Michal P?ibyl  Dalimil ?nita  Milo? Marek 《Biomicrofluidics》2007,1(2)

A seven channel polystyrene (PS) microchip has been constructed using a micromilling machine and a high-temperature assembling. Protein A (PA) has been immobilized by a passive sorption on the microchannel walls. Two bioaffinity assays with human immunoglobulin G (hIgG) as a ligand have been carried out. (i) PA as the receptor and fluorescently labeled hIgG (FITC-hIgG) as the ligand, (ii) PA as the receptor with hIgG as the quantified ligand and fluorescently labeled goat anti-human IgG (FITC-gIgG) as the secondary ligand. One incubation step of the assays took only 5 min instead of hours typical for enzyme-linked immunosorbent assay applications. Calibration curves of the dependence of a fluorescence signal on the hIgG concentration in a sample have been obtained in one step due to a parallel arrangement of microchannels. A mathematical model of the PA-FITC-hIgG complex formation in the chip has been developed. The values of the kinetic constant of the PA-FITC-hIgG binding (k_on=5.5 m³ mol⁻¹ s⁻¹) and the equilibrium dissociation constant of the formed complex (K_d≤3×10⁻⁶ mol m⁻³) have been obtained by fitting to experimental data. The proposed microchip enables fast evaluation of kinetic and equilibrium constants of ligand-receptor bioaffinity pairs and the ligand quantification. As the use of microfluidic chips for immunoassays is often limited by price, we used procedures and chemicals that allow for an inexpensive construction and operation of the microdevice, e.g., temperature assembling as a fabrication technique, detection via an ordinary digital camera, nonspecific polystyrene as a substrate, passive sorption of biomolecules as an immobilization technique, etc.  相似文献   

Structures of Constant Rate Word Problems: A functional approach analysis     

Michal Yerushalmy  Shoshana Gilead 《Educational Studies in Mathematics》1999,39(1-3):185-203

Many recent projects have lately explored function-based approaches to algebra. For the last five years we developed and tested such an approach to algebra, the 'Visual Mathematics'¹ curriculum, in grades seven to nine. While teaching this curriculum we learned from our students' work that while functions form an important basis for solving various sorts of algebra word problems, they introduce some tension in dealing with other sorts of word problems. The data accumulated during our experiments led us to conjecture that viewing algebra rate problems through a function lens offers new ways to look at similarities and differences among word problems. This article presents a theoretical framework for a systematic investigation of the structures of algebra word problems and their relationship to function-based solutions. We think that for those who take a function approach to algebra, this paper suggests new insights into the categorization of word problems. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Examining the psychometric properties of the Infant–Toddler Environment Rating Scale-Revised Edition in a high-stakes context     

Rossana Bisceglia  Michal Perlman  Diana Schaack  Jennifer Jenkins 《Early childhood research quarterly》2009,24(2):121-132

The psychometric properties of the Infant–Toddler Environment Rating Scale-Revised Edition (ITERS-R) were examined using 153 classrooms from child-care centers where resources were tied to center performance. An exploratory factor analysis revealed that the scale measures one global aspect of quality. To decrease redundancy, subsets of items were selected randomly and by experts who rated items according to ease of administration and importance to quality. The shorter subsets demonstrated good discriminant validity, adequate to good psychometric properties, and high associations to the full ITERS-R score. They also demonstrated similar associations to staff education and staff-to-child ratio, as the full instrument. The best assessment of quality was demonstrated by the shortened subset that included items that assess both structural and process features of quality. Multilevel-analyses indicated that classrooms from the same providers score more similarly on ITERS-R than classrooms from other providers. The implications for using the ITERS-R in high-stakes contexts are discussed.  相似文献   

The development of dynamic inquiry performances within an open inquiry setting: A comparison to guided inquiry setting     

Irit Sadeh  Michal Zion 《科学教学研究杂志》2009,46(10):1137-1160

Dynamic inquiry learning emphasizes aspects of change, intellectual flexibility, and critical thinking. Dynamic inquiry learning is characterized by the following criteria: learning as a process, changes during the inquiry, procedural understanding, and affective points of view. This study compared the influence of open versus guided inquiry learning approaches on dynamic inquiry performances among high‐school biology students. We hypothesized that open inquiry students who engage in the inquiry process from its initial stage, participating in the decision making process of asking inquiry questions and planning all aspects of the inquiry, will outperform students who experienced guided inquiry, in terms of developing dynamic inquiry performances. Students were divided into two groups: guided and open inquiry learning approaches. Both groups were followed throughout their 2‐year inquiry learning process. The data sources included interviews, students' inquiry summary papers, logbooks, and reflections. A quantitative content analysis of the two groups, using a dynamic inquiry performances index, revealed that open inquiry students used significantly higher levels of performances in the criteria “changes during inquiry” and “procedural understanding.” However, the study's results indicated no significant differences in the criteria “learning as a process” and “affective points of view.” The implementation of dynamic inquiry performances during inquiry learning may shed light on the procedural and epistemological scientific understanding of students conducting inquiries. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 1137–1160, 2009  相似文献   

Blocking landing techniques in volleyball and the possible association with anterior cruciate ligament injury     

David Zahradnik  Daniel Jandacka  Michal Holcapek  Roman Farana  Jaroslav Uchytil  Joseph Hamill 《Journal of sports sciences》2018,36(8):955-961

The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.  相似文献   

The Effect of Integrating Movement into the Learning Environment of Kindergarten Children on their Academic Achievements     

Ella Shoval  Tal Sharir  Michal Arnon  Gershon Tenenbaum 《Early Childhood Education Journal》2018,46(3):355-364

The aim of this study was to test the notion that integrating movement into the learning environment contributes to the academic achievements of kindergarten students. One hundred and sixty 4–6 year-old kindergarten students participated in the study for 145 days, which included pre- and post-intervention tests in language, mathematics, and non-verbal intelligence. The three interventions consisted of (a) a mindful movement—integrating movement in academic learning, (b) a movement for its own sake—allowing children free movement without providing academic instruction, and (c) a control condition—children engaging in their regular academic environment activities. The findings revealed that the mindful movement intervention resuted in the highest improvement in the academic achievement tests. Children engaging in movement for its own sake did not differ from the control condition. The findings support the notion that mindful movement enhances kindergarten children’s academic achievements. Possible explanations for this outcome are discussed.  相似文献   

Cultural Framework and Objective Obstacles of Arab Students in Two Public Colleges in Israel     

Nitza Davidovitch  Dan Soen  Michal Kolan 《Higher Education in Europe》2007,32(4):359-368

This article presents the results of a survey of 459 Jewish and Arab students at two public colleges in Israel in 2005. The study aimed at gaining understanding of Arab students' access to higher education in comparison to access of Jewish students by the objective obstacles to such access as reflected in the admission profiles and socio‐economic background of Jewish and Arab students at two public colleges. Analyses indicated that these academic campuses constitute a site of encounter for two very different population groups, a fact that has significant implications for access and admission policies, and student aid programs. The findings of this study are the first step in further consideration of issues relating to equal opportunities and access to higher education for Arab students, and shed light on potential means for reducing the gaps between Arab students and their Jewish counterparts.  相似文献   

Job change in later life: A process of marginalization?     

Martin Nekola  Andrea Principi  Michal Švarc  Markéta Nekolová  Deborah Smeaton 《Educational gerontology》2018,44(7):403-415

Adopting a longitudinal approach, this article examines downward occupational mobility (DOM) later in working life and its effects on job satisfaction and perceptions of working conditions of older workers in Europe. The main aim was to test whether the risk that workers will be negatively impacted and marginalized in the labor market due to demotion into lower quality jobs is offset by benefits. Based on an ordinal logistic regression of merged Survey of Health, Ageing and Retirement in Europe and English Longitudinal Study of Ageing datasets, the study found a positive significant impact of DOM on overall job satisfaction. Moreover, DOM was associated with a statistically significant reduction in workload pressure, although it did increase physical work demand. This article adds to the literature on marginalization of workers with indications that the lower income and status associated with DOM at older ages may have offsetting benefits.  相似文献   

Academic expectations and actual achievements: the roles of hope and effort     

Uzi Levi  Michal Einav  Orit Ziv  Ilana Raskind  Malka Margalit 《European Journal of Psychology of Education - EJPE》2014,29(3):367-386

This study sought to extend the research on adolescents' hope, academic expectations, and average grades. The hope theory (Snyder, Psychological Inquiry 13(4):249–275, 2002), the salutogenic paradigm (with a focus on sense of coherence (SOC) (Antonovsky 1987)), and Bandura's (Journal of Management 38(1):9–44, 2012) social learning theory (with a focus on three self-efficacy (SE) constructs: academic SE, social SE, and emotional SE), were used as an integrated conceptual framework for predicting expected and actual academic performance. The sample consisted of 289 10th grade high school students (152 girls and 137 boys). The structural equation modeling (SEM) analysis provided support for the hypothesized modified model. The results demonstrated that hopeful thinking had a direct effect on grade expectations, which, in turn, predicted academic achievement. In addition, SOC, social SE, emotional SE, and academic SE were interrelated, but only emotional SE and SOC contributed directly to hope. Academic SE predicted effort, which also contributed to hope. Thus, the relations between students' investment of effort and actual grades were predicted indirectly through hopeful thinking and grade expectations. The implications for future research and the field of educational psychology of using hope, SOC, and SE as an integrated conceptual framework for predicting academic outcomes are discussed.  相似文献   

How Moroccan mothers and fathers view child development and their role in their children's education     

Gail L. Zellman  Michal Perlman  Rita Karam 《International Journal of Early Years Education》2014,22(2):197-209

Despite the documented importance of parental engagement in early learning, little is known about how parents in the Middle East and North Africa understand child development. To inform the literature, a small-scale study involving four focus groups was conducted with parents of children aged six years and under living in Casablanca. The purpose of this study was to explore parents' understanding of and support for their children's early development. Results reveal that parents see a vital role for themselves in their children's upbringing as supporters and nurturers, but little role as teachers. Across different education and income levels, parents in this small-scale qualitative study believe that children's experiences in their first years of life do not affect their longer-term intellectual development or school success and see little value in early intellectual stimulation or formal preschool education. Our results suggest that parents need to understand their role as their child's first educators. Also, it is essential that parents are taught how to promote their children's early cognitive development without undermining their nurturing roles.  相似文献