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Ray resections have been a viable treatment option for patients with tumors, trauma, infection, vascular insufficiency, or other abnormalities of the hand since the procedure was described in the 1920s. The creation of a functional hand after central ray resection presents unique technical challenges: insufficient closure of the gap between the metacarpals bordering the resected ray can produce an enlarged space between remaining digits and potentially cause digital malrotation, both of which negatively affect hand function. The goal is to make the space between resulting fingers as close to normal as possible. A number of procedures were described to address this issue, but unfortunately, they can be technically onerous and may require prolonged immobilization, the use of internal hardware, or the use of temporary hardware requiring removal.We describe a technique for amputation of the affected ray at the proximal metacarpal metadiaphyseal flare and a concomitant closing wedge osteotomy to allow superior gap closure between the residual fingers while maintaining the structure of the carpus and alignment of the hand. This improves functional and aesthetic outcomes after central ray resection of the hand. Key words: Metacarpal ray resection, Middle ray amputation, Ray amputation hand

The global disruption caused by the COVID-19 pandemic has impacted every sector in society. Education has been affected at all levels, from kindergarten to Continuing Professional Development, as i...

Fractal analysis and the calculation of fractal dimension offer the potential for the numerical characterisation of places by providing a synthetic measurement of place complexity. This paper provides a fractal analysis of street vistas linking the calculation of fractal dimension to the perception of levels of visual variety present in everyday urban streets. A technique for calculating street vista fractal dimensions of textures extracted from greyscale images is presented, and correlations between the resultant fractal dimension and scores for perceived visual variety are discussed.

Central to the success of microfluidic systems has been the development of innovative methods for the manipulation of fluids within microchannels. We demonstrate a method for generating flow within a microfluidic channel using an optically driven pump. The pump consists of two counter rotating birefringent vaterite particles trapped within a microfluidic channel and driven using optical tweezers. The transfer of spin angular momentum from a circularly polarised laser beam rotates the particles at up to 10 Hz. We show the that the pump is able to displace fluid in microchannels, with flow rates of up to 200 μm 3 s -1 (200 fL s -1 ). The direction of fluid pumping can be reversed by altering the sense of the rotation of the vaterite beads. We also incorporate a novel optical sensing method, based upon an additional probe particle, trapped within separate optical tweezers, enabling us to map the magnitude and direction of fluid flow within the channel. The techniques described in the paper have potential to be extended to drive an integrated lab-on-chip device, where pumping, flow measurement and optical sensing could all be achieved by structuring a single laser beam.

Open microfluidic channels were used to separate the extracellular space around a cardiomyocyte into three compartments: the cell ends and a central partition (insulating gap). The microchannels were filled with buffer solution and overlaid with paraffin oil, thus forming the cavities for the cell ends. The central part of the cardiomyocyte rested on the partition between two adjacent microchannels and was entirely surrounded by the paraffin oil. This arrangement increased the extracellular electrical resistance to20 MOmega and facilitated the recording of the time course of the change in extracellular voltage and current during subthreshold and suprathreshold stimuli. The waveform of the extracellular current and voltage in response to an extracellular depolarizing stimulus comprised an initial monophasic signal followed by a biphasic signal with a delay of 2-15 ms. The latter was associated with a transient contraction and therefore caused by an action potential. The biphasic signal became monophasic after the depolarization of one cell end by raised extracellular [K+]. This form of differential recording revealed the repolarization phase of the action potential. At rest, the sarcomere length within the gap was 12% +/- 4.8% longer than outside the gap, but intracellular Ca2+ transients occurred to the same extent as that observed in the outer pools. This data demonstrate the feasibility of the use of a microfluidic bath design to limit the extracellular resistance between two ends of an isolated cardiomyocyte.

We demonstrate controllable poration within ≈1 µm regions of individual cells, mediated by a near-IR laser interacting with thin-layer amorphous silicon substrates. This technique will allow new experiments in single-cell biology, particularly in neuroscience. As our understanding of the fundamental mechanistic processes underpinning biology expands, so does the need for high-precision tools to allow the dissection of the heterogeneity and stochastic processes that dominate at the single- and sub-cellular level. Here, we demonstrate a highly controllable and reproducible optical technique for inducing poration within specific regions of a target cell’s plasma membrane, permitting localized delivery of payloads, depolarization and lysis experiments to be conducted in unprecedented detail. Experiments support a novel mechanism for the process, based upon a thermally-induced change triggered by the interactions of a near-IR laser with a biocompatible thin film substrate at powers substantially below that used in standard optoporation experiments.