Instructional leadership practices in Singapore

This paper presents a review of the literature on principal instructional leadership in Singapore. The authors investigated the dimensions of instructional leadership in the practices of Singapore principals and highlighted the strategies these leaders adopt to enact their instructional roles. Singapore principals were found to play an active role in defining the school vision and promoting the school climate. However, in the areas of curriculum implementation and classroom instruction, the middle management team in the school played more active roles as compared to principals. Five broad conclusions were discussed to provide perspectives on instructional leadership practices in Singapore. This paper also highlighted limitations on current instructional leadership research in Singapore and pointed to areas of future research.     

Dialogue with a conversational agent promotes children’s story comprehension via enhancing engagement

Dialogic reading, when children are read a storybook and engaged in relevant conversation, is a powerful strategy for fostering language development. With the development of artificial intelligence, conversational agents can engage children in elements of dialogic reading. This study examined whether a conversational agent can improve children's story comprehension and engagement, as compared to an adult reading partner. Using a 2 (dialogic reading or non-dialogic reading) × 2 (agent or human) factorial design, a total of 117 three- to six-year-olds (50% Female, 37% White, 31% Asian, 21% multi-ethnic) were randomly assigned into one of the four conditions. Results revealed that a conversational agent can replicate the benefits of dialogic reading with a human partner by enhancing children's narrative-relevant vocalizations, reducing irrelevant vocalizations, and improving story comprehension.     

Government support for SME innovations in the regional industries: The case of government financial support program in South Korea

This study explores the impact of governmental support policies on the innovation of SMEs in the regional strategic industries in South Korea. We use the technological development assistance funds as a proxy for governmental support policies for SMEs in the regional industries in Korea. The innovation of SMEs is measured by technological innovation: patent, utility model, trademark, and new design registrations. Before empirically testing the impact of governmental support policies on the innovation of SMEs, this study reviews the literature concerning the innovation and the governmental support policies of SMEs in regional industries. Results from empirical models, which simultaneously control for factors which were thought to affect the innovation of regional SMEs, indicate that a positive relationship exists among the technological development assistance by the Korean government and patent acquisitions and new design registrations of regional SMEs. Networks with universities also have a positive relationship with patent acquisitions and new design registrations of regional SMEs. This study suggests there is an importance to governmental financial aids for regional SME innovations, and there is an importance to the need to build a strong social relationship in today's networked economy.     

Dual-mode on-demand droplet routing in multiple microchannels using a magnetic fluid as carrier phase

We present dual-mode, on-demand droplet routing in a multiple-outlet microfluidic device using an oil-based magnetic fluid. Magnetite (Fe₃O₄) nanoparticle-contained oleic acid (MNOA) was used as a carrier phase for droplet generation and manipulation. The water-in-MNOA droplets were selectively distributed in a curved microchannel with three branches by utilizing both a hydrodynamic laminar flow pattern and an external magnetic field. Without the applied magnetic field, the droplets travelled along a hydrodynamic centerline that was displaced at each bifurcating junction. However, in the presence of a permanent magnet, they were repelled from the centerline and diverted into the desired channel when the repelled distance exceeded the minimum offset allocated to the channel. The repelled distance, which is proportional to the magnetic field gradient, was manipulated by controlling the magnet''s distance from the device. To evaluate routing performance, three different sizes of droplets with diameters of 63, 88, and 102 μm were directed into designated outlets with the magnet positioned at varying distances. The result demonstrated that the 102-μm droplets were sorted with an accuracy of ∼93%. Our technique enables on-demand droplet routing in multiple outlet channels by simply manipulating magnet positions (active mode) as well as size-based droplet separation with a fixed magnet position (passive mode).     

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.     

Examination of the role of transient receptor potential vanilloid type 4 in endothelial responses to shear forces

Shear stress is the major mechanical force applied on vascular endothelial cells by blood flow, and is a crucial factor in normal vascular physiology and in the development of some vascular pathologies. The exact mechanisms of cellular mechano-transduction in mammalian cells and tissues have not yet been elucidated, but it is known that mechanically sensitive receptors and ion channels play a crucial role. This paper describes the use of a novel and efficient microfluidic device to study mechanically-sensitive receptors and ion channels in vitro, which has three independent channels from which recordings can be made and has a small surface area such that fewer cells are required than for conventional flow chambers. The contoured channels of the device enabled examination of a range of shear stresses in one field of view, which is not possible with parallel plate flow chambers and other previously used devices, where one level of flow-induced shear stress is produced per fixed flow-rate. We exposed bovine aortic endothelial cells to different levels of shear stress, and measured the resulting change in intracellular calcium levels ([Ca²⁺]_i) using the fluorescent calcium sensitive dye Fluo-4AM. Shear stress caused an elevation of [Ca²⁺]_i that was proportional to the level of shear experienced. The response was temperature dependant such that at lower temperatures more shear stress was required to elicit a given level of calcium signal and the magnitude of influx was reduced. We demonstrated that shear stress-induced elevations in [Ca²⁺]_i are largely due to calcium influx through the transient receptor potential vanilloid type 4 ion channel.