Programmed sample delivery on a pressurized paper

This paper reports a method to control the fluid flow in paper-based microfluidic devices simply by pressing over the channel surface of paper, thereby decreasing the pore size and permeability of a non-woven polypropylene sheet. As a result, fluid resistance is increased in the pressed region and causes flow rate to decrease. We characterize the decrease of flow rate with respect to different amounts of pressure applied, and up to 740% decrease in flow velocity was achieved. In addition, we demonstrate flow rate control in a Y-shaped merging paper and sequential delivery of multiple color dyes in a three-branched paper. Furthermore, sequential delivery of multiple fluid samples is performed to demonstrate its application in multi-step colorimetric immunoassay, which shows a 4.3-fold signal increase via enhancement step.     

Optofluidic microvalve-on-a-chip with a surface plasmon-enhanced fiber optic microheater

We present an optofluidic microvalve utilizing an embedded, surface plasmon-enhanced fiber optic microheater. The fiber optic microheater is formed by depositing a titanium thin film on the roughened end-face of a silica optical fiber that serves as a waveguide to deliver laser light to the titanium film. The nanoscale roughness at the titanium-silica interface enables strong light absorption enhancement in the titanium film through excitation of localized surface plasmons as well as facilitates bubble nucleation. Our experimental results show that due to the unique design of the fiber optic heater, the threshold laser power required to generate a bubble is greatly reduced and the bubble growth rate is significantly increased. By using the microvalve, stable vapor bubble generation in the microchannel is demonstrated, which does not require complex optical focusing and alignment. The generated vapor bubble is shown to successfully block a liquid flow channel with a size of 125 μm × 125 μm and a flow rate of ∼10 μl/min at ∼120 mW laser power.     

Tilted post arrays for separating long DNA

Recent simulations by Chen and Dorfman [Electrophoresis 35, 405–411 (2014)] suggested that “tilting” the electric field with respect to the lattice vectors of a hexagonal post array would lead to a substantial improvement in electrophoretic DNA separations therein. We constructed such an array where the electric field is applied at an angle equidistant between the two lattice vectors. This tilted array leads to (i) baseline resolution of 20 kbp DNA and λ DNA (48.5 kbp) in a 4 mm channel and (ii) measurable separation resolutions for electric fields up to 50 V/cm, both of which are improvements over untilted post arrays of the same post density. The predicted time required to reach a resolution of unity is approximately 5 min, independent of electric field. The separations are more reproducible at higher fields.     

‘Active Citizens’: the case of school governors

ABSTRACT

This article reviews current and historical debates about active, participant citizens and related conceptions of citizenship. In particular it focusses on the prospects for the participation of citizens in the administration of public bodies. It discusses critically the notion of participative citizenship and active citizenship as articulated by Douglas Hurd (when Home Secretary) and also the version contained in the report of the Speaker's Commission on Citizenship. The article then draws upon research conducted for the Volunteer Centre, by the National Foundation for Educational Research and that by Brehony and Deem which is funded by an Economic and Social Research Council Grant (R000 23 1799), on voluntary activity and school governors, respectively. The applicability of the concept of active citizenship to the oversight of schools by school governing bodies is then considered alongside recent work in the United States. The article then considers the constraints upon active citizenship which prevent many governors from participating as much as the role demands and it ends with a reference to the tension between those who see governing bodies as an arena for democratic accountability and the active participation of citizens and those who view them principally as a means by which the local state is weakened and its functions increasingly transferred to the voluntary sector.     

Teacher Acceptability of Functional Assessment-Derived Treatments

This study examines whether teachers find a treatment clearly linked to a functional assessment more acceptable than treatments based on arbitrarily selected reinforcers. We randomly assigned 111 elementary school teachers to 3 experimental conditions. In all conditions, a problem vignette was read that included the same functional assessment summary but varied according to whether the treatment recommendation was linked to the assessment results. A one-way analysis of variance revealed significantly higher pretreatment acceptability ratings and likelihood of use for the treatment linked to assessment. Implications of these results for school-based consultation are discussed.     

Intellectual self-mutilation

[The] business man is generous to a fault, but one thing he does demand of all teachers and lecturers and journalists: if we're going to pay them our good money, they‘ve got to help us by selling efficiency and whooping it up for rational prosperity? And when it comes to these blab-mouth, fault-finding, pessimistic, cynical University teachers, let me tell you that during this golden coming year it's just as much our duty to bring influence to have these cusses fired as it is to sell all the real estate and gather in all the good shekels we can. Sinclair Lewis. Babbitt.