Publications by authors named "William Ducker"

Biofilms reduce antibiotic efficacy and lead to complications and mortality in human and equine patients with orthopedic infections. Equine bone marrow-derived mesenchymal stromal cells (MSC) kill planktonic bacteria and prevent biofilm formation, but their ability to disrupt established orthopedic biofilms is unknown. Our objective was to evaluate the ability of MSC to reduce established S.

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Evaporation of small water droplets on solids is hindered because surface tension pulls the droplet into a spherical cap that has a small perimeter. Our solution is to coat a solid with a very thin, porous layer into which the droplet flows to create a large-area disk with concomitant high rate of evaporation. We investigate evaporation by varying factors that have not been previously considered: pore size and distribution, contact angle, temperature, and relative humidity (RH).

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In this work, we quantitatively compare computer simulations and existing cell tracking data of P. aeruginosa surface motility in order to analyse the underlying motility mechanism. We present a three dimensional twitching motility model, that simulates the extension, retraction and surface association of individual Type IV Pili (TFP), and is informed by recent experimental observations of TFP.

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Polycationic polymers are widely studied antiseptics, and their efficacy is usually quantified by the solution concentration required to kill a fraction of a population of cells (e.g., by Minimum Bactericidal Concentration (MBC)).

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Antimicrobial coatings can inhibit the transmission of infectious diseases when they provide a quick kill that is achieved long after the coating application. Here, we describe the fabrication and testing of a glass coating containing AgO microparticles that was prepared from sodium silicate at room temperature. The half-lives of both methicillin-resistant (MRSA) and on this coating are only 2-4 min.

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Some very effective antimicrobial coatings exploit copper or cuprous oxide (CuO) as the active agent. The aim of this study is to determine which species is the active antimicrobial - dissolved ions, the CuO solid, or reactive oxygen species. Copper ions were leached from CuO into various solutions and the leachate tested for both dissolved copper and the efficacy in killing Pseudomonas aeruginosa.

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Evaporation of water using solar power is an economical and environmentally friendly method for purification of aqueous solutions. It has been suggested that intermediate states can be used to lower the enthalpy of evaporation of water and therefore to increase the efficiency of evaporation that uses absorption of sunlight. However, the relevant quantity is the enthalpy of evaporation from bulk water to bulk vapor, which is fixed for a given temperature and pressure.

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Antimicrobial coatings have a finite lifetime because of wear, depletion of the active ingredient, or surface contamination that produces a barrier between the pathogen and the active ingredient. The limited lifetime means that facile replacement is important. Here, we describe a generic method for rapidly applying and reapplying antimicrobial coatings to common-touch surfaces.

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Antimicrobial coatings can be used to reduce the transmission of infectious agents that are spread by contact. An effective coating should kill microbes in the time between users, which is sometimes minutes or less. Fast killing requires fast transport, and our proposed method of fast transport is a porous coating where the contaminated liquid imbibes (infiltrates) into the pores to achieve rapid contact with active material inside the pores.

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This study investigates how the recent history of bacteria affects their attachment to a solid-liquid interface. We compare the attachment from a flowing suspension of the bacterium,PAO1, after one of two histories: (a) passage through a tube packed with glass beads or (b) passage through an empty tube. The glass beads were designed to increase the rate of bacterial interactions with solid-liquid surfaces prior to observation in a flow cell.

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Hypothesis: The addition of a thin, hydrophilic, porous, coating to an impermeable solid will lead to more rapid evaporation of liquid droplets that impinge on the solid. The droplet will imbibe quickly, but the progress normal to the interface will be limited to the thickness of the coating, and therefore the liquid will spread laterally into a broad disk to expose a large liquid-vapor interface for evaporation.

Experiments: Liquid droplets of volume 2.

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Pathogenic bacteria can remain viable on fabrics for several days and therefore are a source of infection. Antimicrobial fabrics are a potential method of reducing such infections, and advances in antimicrobial fabrics can be enhanced by knowledge of how the fabric kills bacteria. Metal oxides have been considered and used as antimicrobial ingredients in self-sanitizing surfaces, including in clinical settings.

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Previous reports indicated the low stability of severe actute respiratory syndrome coronovirus 2 (SARS-CoV-2) on various porous surfaces, but the role of porosity was unclear because there was no direct comparison between porous and nonporous solids of the same chemistry. Through comparing pairs of solids with very similar chemistry, we find that porosity is important: porous glass has a much lower infectivity than nonporous glass. However, porosity is not sufficient to lower infectivity; permeability, which is the ability of a liquid to move through a material, is the important parameter.

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We measured the diffusion of an anion, fluorescein, confined to a nanoscale (10-100 nm) aqueous film between two glass walls. The two glass walls were very slightly angled to form a crack. The diffusion of fluorescein was strongly influenced by the presence of an inert electrolyte, NaCl, in the film prior to the diffusion of charged fluorescein into the crack.

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Transparent antimicrobial coatings can maintain the aesthetic appeal of surfaces and the functionality of a touch-screen while adding the benefit of reducing disease transmission. We fabricated an antimicrobial coating of silver oxide particles in a silicate matrix on glass. The matrix was grown by a modified Stöber sol-gel process with vapor-phase water and ammonia.

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Transfer of SARS-CoV-2 from solids to fingers is one step in infection via contaminated solids, and the possibility of infection from this route has driven calls for increased frequency of handwashing during the COVID-19 pandemic. To analyze this route of infection, we measured the percentage of SARS-CoV-2 that was transferred from a solid to an artificial finger. A droplet of SARS-CoV-2 suspension (1 µL) was placed on a solid, and then artificial skin was briefly pressed against the solid with a light force (3 N).

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Antimicrobial coatings are one method to reduce the spread of microbial diseases. Transparent coatings preserve the visual properties of surfaces and are strictly necessary for applications such as antimicrobial cell phone screens. This work describes transparent coatings that inactivate microbes within minutes.

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We developed antimicrobial coatings from ZnO particles that reduce the infectivity of SARS-CoV-2 suspensions by >99.9% in 1 h. The advantage of a coating is that it can be applied to a variety of objects, e.

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The COVID-19 pandemic had a major impact on life in 2020 and 2021. One method of transmission occurs when the causative virus, SARS-CoV-2, contaminates solids. Understanding and controlling the interaction with solids is thus potentially important for limiting the spread of the disease.

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The ongoing COVID-19 pandemic has created a need for coatings that reduce infection from SARS-CoV-2 via surfaces. Such a coating could be used on common touch surfaces (e.g.

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SARS-CoV-2, the virus that causes the disease COVID-19, remains viable on solids for periods of up to 1 week, so one potential route for human infection is via exposure to an infectious dose from a solid. We have fabricated and tested a coating that is designed to reduce the longevity of SARS-CoV-2 on solids. The coating consists of cuprous oxide (CuO) particles bound with polyurethane.

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Bacteria traverse surfaces as part of colonizing solids, and it is of interest to hinder this motion to potentially thwart infections in humans. Here, we demonstrate that topographical steps hinder the ability of PAO1 () to traverse a solid-liquid interface. Using time-lapse fluorescence microscopy and image analysis, we analyzed the motion of that were challenged with steps ranging in height from 0.

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Air bubbles are a promising means of controlling fouling for a range of applications, particularly delaying fouling in marine environments. This work investigates the mechanism by which the collision of an air bubble with a solid removes adsorbed bacteria. A key feature of the work is that the numbers of bacteria were monitored via video microscopy throughout the collision; so, we were able to explore the mechanism of bacteria removal.

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Thin films (0-30 nm) of very concentrated aqueous monovalent salt solutions (2-10 M of LiCl, NaCl, and CsCl) were examined to determine how ionic strength affects the screening length of the electrostatic potential. Measurements were consistent with a screening length in the range of 3-12 nm. The screening length increased monotonically as a function of salt concentration, and the rate of increase was a function of the monovalent salt type.

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We describe measurements of adsorption between two flat plates when the plates are separated by 0-65 nm. The objective is to examine how adsorption is affected by confinement in very thin films. It is well known that adsorption of simple ions can change with the thickness of a thin film (charge regulation); here, we describe a direct method to measure adsorption as a function of confinement and results for one example.

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