Polymer brush coatings are frequently prepared by radical polymerization, a notoriously oxygen sensitive process. Glucose oxidase (GOx) can inexpensively enable radical polymerization in solution by enzymatically consuming oxygen as it oxidizes glucose. Here, we report the growth of polymeric brushes using GOx-assisted atom transfer radical polymerization (ATRP) from a surface while open to air. Specifically, we grew a set of biomedically relevant polymer brushes, including poly­(oligo­(ethylene glycol) methacrylate) (POEGMA), poly­(2-dimethylaminoethyl methacrylate) (PDMAEMA), poly­(sulfobetaine methacrylate) (PSBMA), and poly­(2-(methylsulfinyl)­ethyl acrylate (PMSEA). For each of these polymers, we monitored GOx-assisted and GOx-free ATRP reaction kinetics in real time using quartz crystal microbalance (QCM) and verified findings with localized surface plasmon resonance (LSPR). We modeled brush growth kinetics considering bimolecular termination. This model fit our data well (r 2 > 0.987 for all samples) and shows the addition of GOx increased effective kinetic chain lengths, propagation rates, and reproducibility. We tested the antifouling properties of the polymer brush coatings against human blood plasma and were surprised to find that coatings prepared with GOx repelled more plasma proteins in all cases than their GOx-free counterparts.

Observations of the nighttime thermospheric wind from two ground‐based Fabry‐Perot Interferometers are compared to the level 2.1 and 2.2 data products from the Michelson Interferometer Global High‐resolution Thermospheric Imaging (MIGHTI) onboard National Aeronautics and Space Administration's Ionospheric Connection Explorer to assess and validate the methodology used to generate measurements of neutral thermospheric winds observed by MIGHTI. We find generally good agreement between observations approximately coincident in space and time with mean differences less than 11 m/s in magnitude and standard deviations of about 20–35 m/s. These results indicate that the independent calculations of the zero‐wind reference used by the different instruments do not contain strong systematic or physical biases, even though the observations were acquired during solar minimum conditions when the measured airglow intensity is weak. We argue that the slight differences in the estimated wind quantities between the two instrument types can be attributed to gradients in the airglow and thermospheric wind fields and the differing viewing geometries used by the instruments.

We present terminal deoxynucleotidyl transferase-catalyzed enzymatic polymerization (TcEP) for the template-free synthesis of high-molecular-weight, single-stranded DNA (ssDNA) and demonstrate that it proceeds by a living chain-growth polycondensation mechanism. We show that the molecular weight of the reaction products is nearly monodisperse, and can be manipulated by the feed ratio of nucleotide (monomer) to oligonucleotide (initiator), as typically observed for living polymerization reactions. Understanding the synthesis mechanism and the reaction kinetics enables the rational, template-free synthesis of ssDNA that can be used for a range of biomedical and nanotechnology applications.

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Key Points:• The equatorial disturbance dynamo vertical drifts have very strong temporal and solar cycle dependence.• The strongest disturbance dynamo variations occur near dusk.• Previous studies significantly underestimate the variability of equatorial disturbance dynamo vertical plasma drifts. AbstractWe use extensive incoherent scatter radar observations from the Jicamarca Radio Observatory to study the local time and bi-monthly dependence of the equatorial disturbance dynamo vertical plasma drifts on solar flux and geomagnetic activity. We show that the daytime disturbance drifts have generally small magnitudes with largest values before noon and an apparent annual variation. Near dusk, they are downward throughout the year with largest values during the equinoxes and smallest during June solstice. These downward drifts increase strongly with solar flux, and shift to later local times. They also increase with increasing geomagnetically active conditions with no apparent local time shift. The equinoctial evening downward disturbance drifts are larger during the autumnal equinox than during the vernal equinox. The nighttime disturbance drifts are upward and have small seasonal and solar cycle dependence but increase strongly with geomagnetic activity, particularly in the late night sector. Our results are in general agreement with those from previous theoretical and experimental studies, except near dusk where our results show much stronger seasonal and solar cycle dependence.

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We present terminal deoxynucleotidyl transferasecatalyzede nzymatic polymerization (TcEP) for the templatefree synthesis of high-molecular-weight, single-stranded DNA (ssDNA) and demonstrate that it proceeds by al iving chaingrowth polycondensation mechanism. We showt hat the molecular weight of the reaction products is nearly monodisperse,a nd can be manipulated by the feed ratio of nucleotide (monomer) to oligonucleotide (initiator), as typically observed for living polymerization reactions.U nderstanding the synthesis mechanism and the reaction kinetics enables the rational, template-free synthesis of ssDNAthat can be used for ar ange of biomedical and nanotechnology applications.

We used Fabry-Perot Interferometer (FPI) observations at Jicamarca, Nasca, and Arequipa, Peru, from 2011 to 2017 to study the nighttime zonal and meridional disturbance winds over the Peruvian equatorial region. We derived initially the seasonal-dependent average thermospheric winds corresponding to 12 hr of continuous geomagnetically quiet conditions. These quiet-time climatological winds, which are in general agreement with results from the Horizontal Wind Model (HWM14), were then used as baselines for the calculation of the disturbance winds. Our results indicate that the nighttime zonal disturbance winds are westward with peak values near midnight and with magnitudes much larger than predicted by the Disturbance Wind Model (DWM07). The premidnight equinoctial and June solstice westward disturbance winds have comparable values and increase with local time. The postmidnight westward disturbance winds decrease toward dawn and are largest during equinox and smallest during June solstice. The meridional average disturbance winds have small values throughout the night. They are northward in the premidnight sector, and southward with larger (smaller) values during December solstice (equinox) in the postmidnight sector. We also present observations showing that during the main and recovery phases of the April 2012 and May 2016 geomagnetic storms the zonal disturbance winds have much larger magnitudes and lifetimes (up to about 48 hr) than suggested by the HWM14. These observations highlight the importance of longer-term disturbance wind effects. The large and short-lived (about 2 hr) observed meridional wind disturbances are not reproduced by current climatological empirical models. Key Points:• Nighttime zonal disturbance winds are westward and maximum near midnight; the meridional winds are north (south)ward before (after) midnight • The HWM14 significantly underestimates the nighttime zonal disturbance winds • Empirical forecast of storm-time disturbance winds for large storms can be improved using multiple long-term disturbance parameters NAVARRO AND FEJER 10,417 Average Disturbance WindsMiddle-and low-latitude thermospheric winds can be severely disturbed by geomagnetic storm-driven enhanced energy and momentum input into the high-latitude ionosphere. Figure 3 shows the local time and seasonal dependence of our thermospheric winds for Kp>3 geomagnetic conditions, and the corresponding predictions from the HWM14. In this case, the average solar flux ranged from 105 to 125 sfu for Figure 3. Seasonal comparison of disturbed equatorial thermospheric winds for local geomagnetic conditions, that is, Kp>3, and corresponding predictions from the HWM14 evaluated for Ap=25. The error bars and shadowed regions correspond to the standard deviations.