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Serologic testing of residual blood samples from 812 children from a hospital in New Orleans, LA, between March and May 2020, demonstrated a SARS-CoV-2 seroprevalence of 6.8% based on S and N protein IgG; Black and Hispanic children, and children living in zip codes with lower household incomes were over-represented.

Transforming a shape memory polymer (SMP) based part into a new configuration is typically achieved by increasing the temperature of the material to just above the glass transition temperature (Tg). This paper describes the preparation and testing of an electrically conductive SMP based composite which can be heated beyond Tg through the passage of an electric current at low power levels and with good temperature-time response characteristics. Conductivity was achieved by impregnating the resin with conductive carbon black (CB) using two dispersion techniques. Samples were subjected to tensile deformation tests to assess the effects of strain on the carbon black based conductive networks within the matrix. A series of these tests were performed on each sample to further assess recovery behavior from repeated loading cycles and any ensuing effect on electrical properties. The SMP showed similar strain recovery in repeated loading cycles. The electrical nature of the filled materials, as measured by the resistivity, was found to change, registering an increase and/or decrease, in response to the magnitude of the strain. Three distinct regions could be identified in the resistivity versus strain plots which are explained vis-a-vis filler chain interaction and rearrangement. The data endorses the technique of using electrical actuation as a means of triggering SMPs which can then be an enabling technology in myriad applications in the aerospace, automotive and biomedical fields. Furthermore, the resistivity change data can be used in the design process to predict the response of components manufactured using reconfigurable composites.

To date, only scant data has been reported regarding the anatomy of the radial nerve and profunda brachii artery and their relationships while within the triangular interval of the posterior arm. As this area has recently gained attention for using motor branches of the triceps muscle for nerve transfers, the present study was conducted.Fifteen adult cadavers (30 sides) underwent dissection, observation and quantitation of their triangular intervals and its contents. The relationship between the profunda brachii and radial nerve in the proximal one half and distal one half of this area was documented.The length of the triangular interval had a mean of 6 cm and the width of this area was on average 2.5 cm. Within the triangular interval, we identified on average, 2.5 arterial branches and 2.3 nerve branches from the profunda brachii and radial nerve, respectively. The maximal number of branches of either the artery or nerve within this geometric region was five. In the proximal one half of this area, 75% of the arteries were found anterior to the radial nerve whereas in the distal one half of the interval most nerves were flanked by arterial branches on both medial and lateral sides. Not all branches of the profunda brachii artery were muscular in this region as some were found to supply the adjacent radial nerve. Communication between the profundi brachii artery in the triangular interval and the posterior humeral circumflex artery was found on two left sides (6.7%).We hope that these anatomical data may be useful to the surgeon who utilizes branches of the proximal radial nerve for neurotization procedures or branches of the profunda brachii for flap procedures.

We report a simple technique for moving water droplets on a hydrophilic aluminum surface containing a hydrophobic copper background. A surface tension gradient due to a triangular-shaped wedge moves the droplets towards the end of the wedge which contains more Al surface area. Movement on both horizontal surfaces and surfaces oriented vertically against gravity has been observed. The mode of droplet motion was found to depend on the wedge angle, and the speed was found to depend on both the wedge angle and the droplet contact angles on the Al and Cu.

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