One step antibody-mediated isolation and patterning of multiple cell types in microfluidic devices

Cell-cell interactions play a key role in regeneration, differentiation, and basic tissue function taking place under physiological shear forces. However, current solutions to mimic such interactions by micro-patterning cells within microfluidic devices have low resolution, high fabrication complexity, and are limited to one or two cell types. Here, we present a microfluidic platform capable of laminar patterning of any biotin-labeled peptide using streptavidin-based surface chemistry. The design permits the generation of arbitrary cell patterns from heterogeneous mixtures in microfluidic devices. We demonstrate the robust co-patterning of α-CD24, α-ASGPR-1, and α-Tie2 antibodies for rapid isolation and co-patterning of mixtures of hepatocytes and endothelial cells. In addition to one-step isolation and patterning, our design permits step-wise patterning of multiple cell types and empty spaces to create complex cellular geometries in vitro. In conclusion, we developed a microfluidic device that permits the generation of perfusable tissue-like patterns in microfluidic devices by directly injecting complex cell mixtures such as differentiated stem cells or tissue digests with minimal sample preparation.     

Cognitive behavioural strategies and anxiety in elite orienteers

The primary purpose of this exploratory field study was to examine the use of cognitive behavioural strategies by highly skilled orienteers prior to and during competition. A secondary purpose of the study was to investigate whether differences in the level of qualification in orienteering is related to state anxiety. The subjects were divided into three classes with respect to their international and national records. The first two classes (A and B) were composed of international and national level athletes. The third class (C) included orienteers with unknown international records. Examination of the use of behavioural cognitive strategies during competition indicated that all orienteers reported a moderate use of mental imagery, above moderate use of inner talk and a focus of attention on present action rather than past or future. The other major findings were that prior to competition, superior orienteers reported use of higher self‐efficacy, more positive outcome expectations and more task demand orientation than their less successful counterparts. Top orienteers coped more successfully with pre‐competition anxiety by lowering their anxiety to a more moderate level prior to the actual performance.     

On the Computation of Functionals Over Sample Paths of a Randomly Rotating Rigid Body

This paper deals with the computation of the values of two functionals which are defined over the sample paths of a randomly rotating rigid body. It is assumed that the body is subjected to two different kinds of perturbation. The first kind of perturbation is represented by the standard Wiener process and the second kind by a homogeneous process with independent increments, finite second-order moments, mean zero and no continuous sample functions. In order to measure quantitatively the stochastic stability of the body's motion, two functionals are defined over its sample paths. It is shown that each of these functionals is a solution to a corresponding partial integro-differential equation. A numerical procedure for the solution of these equations is suggested, and its efficiency and applicability are demonstrated with examples.     

Environmental Problems,Causes, and Solutions: An Open Question

In a national evaluation of environmental literacy in Israel, (Negev, Sagy, Garb, Salzberg, & Tal, 2008 Negev, M., Sagy, G., Garb, Y., Salzberg, A. and Tal, A. 2008. Evaluating the environmental literacy of Israeli elementary and high school students. Journal of Environmental Education, 39(2): 3–20. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), the authors included both multiple choice questions and open questions. In this article the authors describe the qualitative analysis of the answers to an open question regarding a local environmental problem. Most participants specified solid waste, open spaces, or air pollution as the main issues. The perceived solutions were generally at the governmental level, including planning, infrastructure, legislation, and enforcement. The authors describe relations in these responses between the problems, their causes and solutions, and between the quality of these answers and the general environmental literacy of the participants. The authors end with a discussion of the special contributions and potential of open-ended questions for environmental education research.     

The relationship between perception of locus of control and academic achievement: Review and some educational implications

In an attempt to explain the evidence which indicates that internal perception of control is postively related to academic achievement, this paper suggests that mediating motivational and cognitive reactions, which differentiate internals from externals, may account for this relationship. Furthermore, on the basis of data which suggest that the perception of locus of control is a changeable disposition, this paper calls for structuring environments that will induce and maintain realistic internal perception of locus of control.     

Optimal Controls that Maximize the Expectation of First Passage Time

This paper deals with optimal controls that maximize the expectation of first passage time of the state, of a stochastic non-linear system, to the complement of an open and bounded domain. The performance index includes a penalty on the magnitude of the deviation of the first passage time from its expectation. The nonlinear system considered here is subjected to two different kinds of perturbations. The first kind of perturbation is represented by a vector of independent standard Wiener processes and the second kind by a vector of a generalized type of Poisson process.By using a variational approach, necessary conditions on the optimal controls are derived. These conditions are given by a set of four coupled nonlinear partial integro- differential equations. A nonlinear stochastic third-order system is given as a test case, and a numerical method for the computation of its optimal controls, is suggested. The efficiency and applicability of this method are demonstrated with examples.