https://hal.archives-ouvertes.fr/hal-02316307/document

Natural organic matter-cations complexation and its impact on water treatment: A critical review.

Phosphors emitting visible and near-infrared persistent luminescence have been explored extensively owing to their unusual properties and commercial interest in their applications such as glow-in-the-dark paints, optical information storage, and in vivo bioimaging. However, no persistent phosphor that features emissions in the ultraviolet C range (200-280 nm) has been known to exist so far. Here, we demonstrate a strategy for creating a new generation of persistent phosphor that exhibits strong ultraviolet C emission with an initial power density over 10 milliwatts per square meter and an afterglow of more than 2 h. Experimental characterizations coupled with first-principles calculations have revealed that structural defects associated with oxygen introduction-induced anion vacancies in fluoride elpasolite can function as electron traps, which capture and store a large number of electrons triggered by X-ray irradiation. Notably, we show that the ultraviolet C afterglow intensity of the yielded phosphor is sufficiently strong for sterilization. Our discovery of this ultraviolet C afterglow opens up new avenues for research on persistent phosphors, and it offers new perspectives on their applications in terms of sterilization, disinfection, drug release, cancer treatment, anti-counterfeiting, and beyond.

/pdf/x-ray-activated-long-persistent-phosphors-featuring-strong-2tbq90y120.pdf

X-ray-activated long persistent phosphors featuring strong UVC afterglow emissions

https://hal.archives-ouvertes.fr/hal-02107191/document

How closely do mercury trends in fish and other aquatic wildlife track those in the atmosphere? - Implications for evaluating the effectiveness of the Minamata Convention

Biofouling in ultrafiltration process for drinking water treatment and its control by chlorinated-water and pure water backwashing

Polyhalogenated carbazoles (PHCZs) were recently discovered in Great Lakes sediment and other aquatic systems. However, knowledge about their bioaccumulation and potential risks to fish and wildlife remains very limited. The present study investigated PHCZs in Great Lakes lake trout ( Salvelinus namaycush) and walleye ( Sander vitreus; Lake Erie only) composites collected between 2004 and 2016. Median concentrations of ∑PHCZs by lake ranged from 54.7 to 154 ng/g lipid weight or lw (6.8-28.0 ng/g wet weight). Dominant congeners included 3,6-dichlorocarbazole, 1,3,6-tribromocarbazole, and 1,3,6,8-tetrachlorocarbazole. The highest ∑PHCZs concentrations were found in Lakes Michigan and Ontario fish, followed by Lake Huron, whereas Lakes Erie and Superior fish contained the lowest concentrations. Congener profiles of PHCZs also exhibited spatial variations. After age normalization to minimize fish age influence on bioaccumulation rates, fish ∑PHCZs' concentrations declined significantly over time in all lakes except Lake Erie, with slopes ranging from -10.24% to -3.85% per year. The median toxic equivalent (TEQ) of PHCZs due to their dioxin-like activity was determined to range from 8.7 to 25.7 pg/g lw in Great Lakes fish. This study provides the first insight into the bioaccumulation and spatiotemporal trends of PHCZs in Great Lakes and suggests the need for further research on this group of chemicals.

Bioaccumulation and Spatiotemporal Trends of Polyhalogenated Carbazoles in Great Lakes Fish from 2004 to 2016

Mercury (Hg) concentration trends in top predator fish (lake trout and walleye) of the Great Lakes (GL) from 2004 to 2015 were determined by Kendall–Theil robust regression with a cluster-based age normalization method to control for the effect of changes in lake trophic status When data from the GLs (except Lake Erie) are combined, a significant decreasing trend in the lake trout Hg concentrations was found between 2004 and 2015 with an annual decrease of 41% per year, consistent with the decline in regional atmospheric Hg emissions and water Hg concentrations However, a breakpoint was detected with a significant decreasing slope (−81% per year) before the breakpoint (2010), and no trend after the breakpoint When the lakes are examined individually, Lakes Superior and Huron, which are dominated by atmospheric Hg inputs and are more likely than the lower lakes to respond to declining emissions from areas surrounding the GL, have significant decreasing trends with rates between 52 and 78% per year f

Mercury Temporal Trends in Top Predator Fish of the Laurentian Great Lakes from 2004 to 2015: Are Concentrations Still Decreasing?

Combined X-ray diffraction (XRD), helium ion microscopy (HeIM), and 43Ca nuclear magnetic resonance (NMR) results provide novel insight into the nano- and microstructure of flocculated NOM; the mol...

Integrated Molecular and Microscopic Scale Insight into Morphology and Ion Dynamics in Ca2+-Mediated Natural Organic Matter Floccs

Germicidal UVC radiation is a highly effective, chemical-free tool for bacteria inactivation, but its application is limited to reactors and open areas that can accommodate lamps/LEDs and wiring. A relevant example of problematic bacterial colonization within UV-inaccessible confines where chemical techniques have found only limited success is biofouling of feed channels in high-pressure membrane elements for water treatment. Herein we demonstrate a unique method of generating UV internally using embedded radioluminescent (RL) particles excited by an external X-ray source. We further show that the magnitude of the emitted UV intensity and required X-ray dose rates are likely within effective and practical ranges for future application to antibiofouling technology. Assessment of three Pr3+-activated RL phosphor candidates revealed LaPO4:Pr3+ to have the most favorable luminescence properties, achieving over 2-log inactivation of E. coli in a thin water film with a 74 Gy dose of 150 kVp X-rays. The effect o...

Bacteria Inactivation via X-ray-Induced UVC Radioluminescence: Toward in Situ Biofouling Prevention in Membrane Modules

A high stack structure is being developed to increase the 3D NAND Flash storage capacity. However, problems such as bowing, incomplete etching, and twisting occur during the channel hole etching process. For the analysis of these process problems, cross-sectional analysis of devices with high stacks is essential.However, it is difficult to uniformly measure the top and bottom layers of the source line contact and V-NAND string area. Therefore, distortion occurs through cross section analysis. The reasons include the focused ion beam incident beam angle relative to the sample coordinate system, beam current profile, and differential milling.The listed physical parameters can be adjusted in a way to obtain distortion-improved, uniform, and perpendicular image data; however, this time-consuming task is a hindrance when trying to increase the reliability of the analysis.In order to address this problem, we propose an efficient processing technique, abbreviated tomography, which is an efficient data reconstruction method.In this study, 248 images were prepared to set up the tomography algorithm data set. The data was reconstructed in a significantly reduced time using the abbreviated tomography technique. Although it took an average of 5 h to obtain 248 new 2D images, we were able to reconstruct the data in 4 min using the abbreviated tomography technique. This abbreviated tomography algorithm can be used as an efficient reconstruction tool for studying structure at the most basic level.

Timothy A. Johnson

Papers

Mercury Temporal Trends in Top Predator Fish of the Laurentian Great Lakes from 2004 to 2015: Are Concentrations Still Decreasing?

Integrated Molecular and Microscopic Scale Insight into Morphology and Ion Dynamics in Ca2+-Mediated Natural Organic Matter Floccs

Bacteria Inactivation via X-ray-Induced UVC Radioluminescence: Toward in Situ Biofouling Prevention in Membrane Modules

Abbreviated tomography techniques for quick correction of slides in 3-Dimensional NAND Flash architectures