Although copper-containing nanoparticles are used in commercial products such as fungicides and bactericides, we presently do not understand the environmental impact on other organisms that may be inadvertently exposed. In this study, we used the zebrafish embryo as a screening tool to study the potential impact of two nano Cu-based materials, CuPRO and Kocide, in comparison to nano-sized and micron-sized Cu and CuO particles in their pristine form (0 -10 ppm) as well as following their transformation in an experimental wastewater treatment system. This was accomplished by construction of a modeled domestic septic tank system from which effluents could be retrieved at different stages following particle introduction (10 ppm). The Cu speciation in the effluent was identified as non-dissolvable inorganic Cu(H 2 PO 2 ) 2 and non-diffusible organic Cu by X-ray diffraction, inductively coupled plasma mass spectrometry (ICP-MS), diffusive gradients in thin-films (DGT), and Visual MINTEQ software. While the nanoscale materials, including the commercial particles, were clearly more potent (showing 50% hatching interference above 0.5 ppm) than the micron-scale particulates with no effect on hatching up to 10 ppm, the Cu released from the particles in the septic tank underwent transformation into non-bioavailable species that failed to interfere with the function of the zebrafish embryo hatching enzyme. Moreover, we demonstrate that the addition of humic acid, as an organic carbon component, could lead to a dose-dependent decrease in Cu toxicity in our high content zebrafish embryo screening assay. Thus, the use of zebrafish embryo screening, in combination with the effluents obtained from a modeled exposure environment, enables a bioassay approach to follow the change in the Supporting Information AvailableAdditional information on water quality characterizations, SEM and TEM images, XRD spectra of Cu particles, dose-response analysis of percent hatching, XRD spectra of effluents from nano Cu treated septic tank are provided online free of charge via the Internet at http://pubs.acs.org. We also provide information on characterization of the septic system, including alkalinity, conductivity, and hardness. Author Manuscript speciation, and hazard potential of Cu particles instead of difficult-to-perform direct particle tracking. HHS Public AccessKeywords copper particles; transformation; speciation; wastewater treatment; zebrafish; high content screening Nano-enabled Cu products are increasingly being used for commercial applications, including as antibacterial and antifungal agents that can be applied for spraying of vegetation or as a marine anti-fouling paint on the hulls of boats and ships. [1][2][3][4][5][6][7] For example, CuPRO and Kocide are Cu(OH) 2 -based nano-products used as antifungal agents to spray agricultural crops and lawns. While clearly beneficial for eradicating bacterial and fungal growth, inadvertent exposure of other environmental species, such as fish or fish embryos, has not received suff...
Li[Ni1/3Co1/3Mn1/3]O2 (L333) has been successfully synthesized through a two-step coprecipitation and annealing method. Crystal phase and growth behavior were monitored by X-ray diffraction (XRD), while particle morphologies were observed by SEM and TEM. The crystal growth mechanisms during the annealing process were interpreted, and the growth exponent and activation energy for crystal growth were calculated. At low temperatures (e.g., 600 °C), L333 crystals are quite small (ca. 14 nm). Significant crystal growth occurs above 750 °C with crystallite diameters increasing to 850 ± 10 nm after 3 h at 1000 °C.
Titanium dioxide (TiO2) has been widely used as an advanced semiconductor and as a white pigment for many years. In recent years, TiO2 has gained much more interest for its semiconducting properties for use as photocatalytic and photovoltaic materials. Understanding the fundamental nucleation and growth mechanisms is crucial to controlling microstructure and properties for these applications. Nanosized rutile and anatase particles were synthesized from a water-soluble titanium(IV) precursor using a hydrothermal method. The impact of various hydrothermal conditions on the formation, phase, morphology, and grain size of the TiO2 products was investigated using XRD, TEM, and FTIR. At near neutral pH, aggregated rutile rods are formed. By increasing the alkalinity of the reaction medium, the anatase phase was favored and, as expected, larger particle sizes resulted from longer duration reactions. The effects of reaction conditions are discussed with respect to coordination chemistry and coarsening mechanisms.
We report the synthesis and nanostructural development of polycrystalline and single crystalline LiFePO 4 (LFP) nanostructures using a solvothermal media (i.e., water− tri(ethylene glycol) mixture). Crystal phase and growth behavior were monitored by powder and synchrotron X-ray diffraction, as well as transmission electron microscopy (TEM), while particle morphologies were examined using scanning electron microscopy (SEM). Initially, thin (100 nm) platelets of Fe 3 (PO 4 ) 2 • 8H 2 O (vivianite, VTE) formed at short reaction times followed by the nucleation of LFP (20 nm particles) on the metastable VTE surfaces. Upon decrease in pH, primary LFP nanocrystals subsequently aggregated into polycrystalline diamond-like particles via an oriented attachment (OA). With increasing reaction time, the solution pH further decreased, leading to a dissolution−recrystallization process (i.e., Ostwald ripening, OR) of the oriented polycrystalline LFP particles to yield evenly sized, single crystalline LiFePO 4 . Samples prepared at short reaction durations demonstrated a larger discharge capacity at higher rates compared with the single crystalline particles. This is due to the small size of the primary crystallites within larger secondary LiFePO 4 particles, which reduced the lithium ion diffusion path while subsequently maintaining a high tap density. Understanding the relationship between solution conditions and nanostructural development as well as performance revealed by this study will help to develop synthetic guidelines to enable efficient lithium ion battery performance.
e Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. Insect vectors transmit numerous pathogens to a wide range of animal and plant hosts. Hemipteran vectors, such as aphids, leafhoppers, and whiteflies, are an economically important group of insects because they are the dominant vectors of plant pathogens (1). The molecular determinants of transmission have been explored for only a few phytopathosystems (compared to mammalian systems), with virus-vector interactions being the most extensively studied. Surface entities, such as virion capsid components, have been shown to be important for the retention and transmission of plant viruses (2), indicating the importance of pathogen surface properties in mediating these interactions. However, we have much less information regarding the molecular mechanisms of insect transmission of bacterial pathogens, specifically those infecting plants.Xylella fastidiosa is a Gram-negative bacterium that causes diseases in several economically important crops, including Pierce's disease (PD) of grapevines, citrus variegated chlorosis, and almond leaf scorch. X. fastidiosa forms biofilms within the xylem vessels of plant hosts, which occludes vessels and impedes water flow within the vine (3). Symptoms of PD include marginal l...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.