No abstract

Electrochemically controlled nanopipettes are becoming increasingly versatile tools for a diverse range of sequencing, sizing, and imaging applications. Herein, the use of nanopipettes to induce and quantitatively monitor crystallization and dissolution in real time is considered, using CaCO3 in aqueous solution as an exemplar system. The bias between a quasi‐reference counter electrode in a nanopipette and one in a bulk solution is used to mix (or de‐mix) two different solutions by ion migration and drive either growth or dissolution, depending on the polarity. Furthermore, Raman spectroscopy can be applied simultaneously to identify polymorphs formed in the nanopipette. The technique is supported with a robust finite element method model that allows the extraction of time‐dependent saturation levels and mixing characteristics at the nanoscale. The technique shows great promise as a tool for rapidly screening growth additives and inhibitors, allowing eight different additives to be ranked in order of efficacy for crystal growth rate inhibition.

(2016) Combinatorial localized dissolution analysis : application to acid-induced dissolution of dental enamel and the effect of surface treatments. Journal of Colloid and Interface Science, 476. pp. 94-102. Permanent WRAP URL:http://wrap.warwick.ac.uk/81648 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. A combination of scanning electrochemical cell microscopy (SECCM) and atomic force microscopy (AFM) is used to quantitatively study the acid-induced dissolution of dental enamel. A micron-scale liquid meniscus formed at the end of a dual barrelled pipette, which constitutes the SECCM probe, is brought into contact with the enamel surface for a defined period. Dissolution occurs at the interface of the meniscus and the enamel surface, under conditions of well-defined mass transport, creating etch pits that are then analysed via AFM. This technique is applied to bovine dental enamel, and the effect of various treatments of the enamel surface on acid dissolution (1mM HNO 3) is studied. The treatments investigated are zinc ions, fluoride ions and the two combined. A finite element method (FEM) simulation of SECCM mass transport and interfacial reactivity, allows the intrinsic rate constant for acid-induced dissolution to be quantitatively determined. The dissolution of enamel, in terms of Ca 2+ flux ( 2+ ), is first order with respect to the interfacial proton concentration and given by the following rate law:, with 0 = 0.099 ±0.008 cm.s -1 . Treating the enamel with either fluoride or zinc slows the dissolution rate, although in this model system the partly protective barrier only extends around 10-20 nm into the enamel surface, so that after a period of a few seconds dissolution of modified surfaces tends towards that of native enamel. A combination of both treatments exhibits the greatest protection to the enamel surface, but the effect is again transient.

There are a number of recent studies detailing the transmission of SARS-CoV-2 (Covid-19) via both Droplet and Aerosol airborne particle routes of infection. Because of this, it is necessary to understand the release of different sized particles in activities such as playing brass instruments in order for an analysis of risk to take place for such activities.In this investigation, the quantity and size of particles released by brass instruments while they are played was analysed for 7 different types of brass instrument. This was contrasted with the same individuals breathing as a comparison for more general activities as well as the effect of a mitigating polycotton barrier over the end of their instruments. To investigate the particles released, the particles were size sorted and counted with a six-channel laser particle counter. Multiple measurements were made by each individual in each condition investigated. The mean concentration exiting across all instruments measured was found to be 1.21×107 ±1.03×106 Aerosol type particles/m3 and 1.43×104 ±9.01×102 Droplet type particles/m3 per minute. When breathing, the mean count was 1.61×107 ±1.33×106 Aerosol type particle/m3 and 5.45×103 ±1.20×103 Droplet type particles/m3. When playing with a barrier cover, the mean number of particles emitted fell to 2.60×106 ±2.11×105 Aerosol type particle/m3 and 5.20×103 ±8.02×102 Droplet type particles/m3. This barrier represented an average 78.5% reduction for the number of respiratory Aerosol type particles and 63.8% reduction for Droplet type particles compared to playing an instrument without the barrier covering.It was investigated what effect playing for a more extended period of time had on the release of particles with comparisons made to singing, breathing and covering the instruments’ bell ends with a barrier cap. This showed that the mean number of Aerosol type particles produced while playing was 5.38×107 ±3.15×106 Aerosol type particles/m3 produced and showed a significant drop in Aerosol type particle production when playing with a barrier used, with a mean average of 2.28×106±8.01×104 Aerosol type particles/m3. Both breathing and singing showed consistent numbers of Aerosol type particles produced with means of 6.59×107 ±7.94×105 Aerosol type particles/m3 and 5.28×107 ±5.36×105 Aerosol type particles/m3 respectively. This showed a drop in mean Aerosol type particles/m of 95.7% when using a barrier cap compared to playing without a barrier.It is concluded that, while playing a brass instrument, the propagation of respiratory Aerosols does occur and, to a smaller extent, so do Droplet size particles, but at a lower level than when the subject was breathing without an instrument. Finally, it was shown that the use of a barrier cap on the bell end of the instrument offers a significant reduction in the production of respiratory Aerosols into the immediate surroundings, which offers a possible mitigation method for playing in groups from the release of Aerosol type particles, especially in hard to ventilate spaces.FundingThis study was supported by funds from Arts Council England covering salary support for AP and KC. The cleanroom facility and particle counter were provisioned by Centre Stage Ltd. The funders did not have a role in the experimental design, data collection, analysis or decision to publish and content of the manuscript.Competing InterestsThe authors have declared working for Brass Bands England, which exists to support brass bands in England and the wider UK.

<p>PDF file - 12K, Ascribed functions of 10-biomarker diagnostic panel.</p>