Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces

Capillary wave phenomena are challenging to study, especially for microfluidics where the wavelengths are short, the frequencies are high, and the frequency distribution is rarely confined to a narrow range, let alone a single frequency. Those that have been studying Faraday capillary waves generated by vertical oscillation have chosen to work at larger scales and at low frequencies as a solution to this problem, trading simplicity in measurement for issues with gravity, boundary conditions, and the fidelity of the subharmonic capillary wave motion. Laser Doppler vibrometry using a Mach–Zehnder interferometer is an attractive alternative: The interface’s motion can be characterized at frequencies up to 40 MHz and displacements of as little as a few tens of picometers.     

Teachers’ experience with inclusive education in Singapore

Teachers’ positive attitude is most critically and consistently associated with successful inclusion. However, little is known about teachers’ first-hand encounters with inclusive education in Singapore. We present findings from a qualitative study on inclusion based on focus group interviews with 202 teachers from 41 resourced primary schools. The data were transcribed and coded using Interpretive Phenomenological Analysis and NVIVO software. Two broad clusters identified were teachers’ positive and negative experiences in implementing inclusion. More reference was made to negative than positive experiences. The most dominant negative experience was stress from challenging behaviours and instructional difficulties of catering adequately for diverse needs in the same classroom. The most salient positive experience was satisfaction with pupils’ progress and new learning for teachers. Classroom practices that facilitated inclusion and the value of training in shaping teachers’ attitudes towards inclusion were highlighted.     

Ultrafast microfluidics using surface acoustic waves

We demonstrate that surface acoustic waves (SAWs), nanometer amplitude Rayleigh waves driven at megahertz order frequencies propagating on the surface of a piezoelectric substrate, offer a powerful method for driving a host of extremely fast microfluidic actuation and micro∕bioparticle manipulation schemes. We show that sessile drops can be translated rapidly on planar substrates or fluid can be pumped through microchannels at 1–10 cm∕s velocities, which are typically one to two orders quicker than that afforded by current microfluidic technologies. Through symmetry-breaking, azimuthal recirculation can be induced within the drop to drive strong inertial microcentrifugation for micromixing and particle concentration or separation. Similar micromixing strategies can be induced in the same microchannel in which fluid is pumped with the SAW by merely changing the SAW frequency to rapidly switch the uniform through-flow into a chaotic oscillatory flow by exploiting superpositioning of the irradiated sound waves from the sidewalls of the microchannel. If the flow is sufficiently quiescent, the nodes of the transverse standing wave that arises across the microchannel also allow for particle aggregation, and hence, sorting on nodal lines. In addition, the SAW also facilitates other microfluidic capabilities. For example, capillary waves excited at the free surface of a sessile drop by the SAW underneath it can be exploited for micro∕nanoparticle collection and sorting at nodal points or lines at low powers. At higher powers, the large accelerations off the substrate surface as the SAW propagates across drives rapid destabilization of the drop free surface giving rise to inertial liquid jets that persist over 1–2 cm in length or atomization of the entire drop to produce 1–10 μm monodispersed aerosol droplets, which can be exploited for ink-jet printing, mass spectrometry interfacing, or pulmonary drug delivery. The atomization of polymer∕protein solutions can also be used for the rapid synthesis of 150–200 nm polymer∕protein particles or biodegradable polymeric shells in which proteins, peptides, and other therapeutic molecules are encapsulated within for controlled release drug delivery. The atomization of thin films behind a translating drop containing polymer solutions also gives rise to long-range spatial ordering of regular polymer spots whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for polymer patterning without requiring surface treatment or physical∕chemical templating.     

Rapid production of protein-loaded biodegradable microparticles using surface acoustic waves

We present a straightforward and rapid surface acoustic wave (SAW) atomization-based technique for encapsulating proteins into 10 μm order particles composed of a biodegradable polymeric excipient, using bovine serum albumin (BSA) as an exemplar. Scans obtained from confocal microscopy provide qualitative proof of encapsulation and show the fluorescent conjugated protein to be distributed in a relatively uniform manner within the polymer shell. An ELISA assay of the collected particles demonstrates that the BSA survives the atomization, particle formation, and collection process with a yield of approximately 55%. The SAW atomization universally gave particles with a textured morphology, and increasing the frequency and polymer concentration generally gave smaller particles (to 3 μm average) with reduced porosity.     

A high-dexterity low-degree-of-freedom hybrid manipulator structure for robotic lion dance

Lion dance is a very popular and lively Chinese traditional art form. A robotic project in Singapore has been dedicated to the design and demonstration for similar traditional art forms using modern mechatronics technology. This paper deals with a novel six-degree-of-freedom （6-DOF） hybrid manipulator with high stiffness, high loading capability and high dexterity, mimicking the lion dancer＇s upper body motions along with the lion head movements. The design of the hybrid manipulator consists of a 2-DOF torso structure in serial configuration and a 4-DOF dual arm structure in parallel configuration. The combined 6-DOF hybrid manipulator can support the weight and dynamics of the lion head during the lion dance performance. Forward kinematics of the manipulator has been formulated and visualized for design purposes. Inverse kinematics of the hybrid manipulator were analytically derived for real-time motion control. Based on the design and modeling, a complete hybrid manipulator has been fabricated, implemented into the robotic lion, and successfully demonstrated for real robotic lion dance performance.     

Contexts,Original Orders,and Item-Level Orientation: Responding Creatively to Users' Needs and Technological Change

This article questions traditional assumptions that archival aggregations must always be rigidly defined. Technology allows archival institutions to respond to users' diverse requirements by empowering them to create multiple groupings and variable orders. To take advantage of these capabilities as archives become increasingly digital, a shift toward item-level orientation will be crucial. Users will still need information about context, but the digital future will almost certainly necessitate abandoning current methods in favor of documenting contextual relationships at item level. Respect for “fonds” and original order will retain some value but will no longer be the primary means of capturing context.     

Reliability of laser Doppler,near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat

This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC_BL). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7–28.4%, 20.2–33.1%, 42.5–59.8%, 7.8–12.4% and 22.2–30.3% for PU, CVC, %CVC_BL, TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r² = 0.062) and TOI (r² = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.     

Experienced physical education teachers reaching their "use-by date": powerless and disrespected

With the needs of experienced teachers potentially overshadowed by a focus on recruitment, the purpose of this study was to retrospectively explore the reasons why three experienced physical education teachers resigned. They were interviewed through Louis and Smith's (1990) quality of work life (QWL) model. Data suggested shared dissatisfactions related to the lack of "genuine" opportunities to participate in educational debate and decision making, and limited professional respect shown by administrators and parents. A physical education teacher's "use-by date" was proposed. Unless these issues are further explored and addressed, quality teachers will continue to abandon the service.     

Pulmonary monoclonal antibody delivery via a portable microfluidic nebulization platform

Nebulizers have considerable advantages over conventional inhalers for pulmonary drug administration, particularly because they do not require coordinated breath actuation to generate and deliver the aerosols. Nevertheless, besides being less amenable to miniaturization and hence portability, some nebulizers are prone to denature macromolecular drugs due to the large forces generated during aerosolization. Here, we demonstrate a novel portable acoustomicrofluidic device capable of nebulizing epidermal growth factor receptor (EGFR) monoclonal antibodies into a fine aerosol mist with a mass median aerodynamic diameter of approximately 1.1 μm, optimal for deep lung deposition via inhalation. The nebulized monoclonal antibodies were tested for their stability, immunoactivity, and pharmacological properties, which confirmed that nebulization did not cause significant degradation of the antibody. In particular, flow cytometry demonstrated that the antigen binding capability of the antibody is retained and able to reduce phosphorylation in cells overexpressing the EGFR, indicating that the aerosols generated by the device were loaded with stable and active monoclonal antibodies. The delivery of antibodies via inhalation, particularly for the treatment of lung cancer, is thus expected to enhance the efficacy of this protein therapeutic by increasing the local concentration where they are needed.     

Teacher Preparation and Inner-City Schools: Sustaining Educational Failure

This article argues that the great majority of teacher education programs have become a sustaining part of urban education's cycle of failure, in particular through the values, stereotypes, and curricular and pedagogical patterns that teacher education inculcates in incipient teachers about difference, minorities, and urban schools and communities. Teacher education's capability lies chiefly in how it understands and treats programmatic minority students, how it encourages a negative perception of urban teaching itself, and how it discourages its students from understanding difference and diversity through the use of an assimilatory multiculturalism, leaving its students stereotypically uninterested in and/or unprepared for urban teaching.