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Hospital-acquired infections are considered a priority for public health systems since they pose a significant burden for society. High-touch surfaces of healthcare centers, including textiles, provide a suitable environment for pathogenic bacteria to grow, necessitating incorporating effective antibacterial agents into textiles. This paper introduces a highly durable antibacterial gel-like solution, Silver Shell™ finish, which contains chitosan-bound silver chloride microparticles. The study investigates the coating's environmental impact, health risks, and durability during repeated washing. The structure of the Silver Shell™ finish was studied using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The TEM images showed a core-shell structure, with chitosan forming a protective shell around groupings of silver microparticles. The field-emission scanning electron microscopy (FESEM) demonstrated the uniform deposition of Silver Shell™ on the surfaces of the fabrics. AATCC Test Method 100 was employed to quantitatively analyze the antibacterial properties of the fabrics coated with silver microparticles. Two types of bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), were used in this study. The antibacterial results showed that after 75 wash cycles, a 100% reduction for both S. aureus and E. coli in the coated samples using crosslinking agents was observed. The coated samples without a crosslinking agent exhibited 99.88% and 99.81% reductions for S. aureus and E. coli after 50 washing cycles. To compare the antibacterial properties toward non-pathogenic and pathogenic strains of the same species, MG1655 model E. coli strain (ATCC 29213) and a multidrug-resistant clinical isolate were used. The results showed the antibacterial efficiency of the Silver ShellTM solution (up to 99.99% reduction) coated on cotton fabric. AATCC-147 was performed to investigate the coated samples' leaching properties and the crosslinking agent's effects against S. aureus and E. coli. All coated samples demonstrated remarkable antibacterial efficacy, even after 75 wash cycles. The crosslinking agent facilitated durable attachment between the silver microparticles and cotton substrate, minimizing the release of particles from the fabrics. Color measurements were conducted to assess the color differences resulting from the coating process. The results indicated fixation values of 44%, 32%, and 28% following 25, 50, and 75 washing cycles, respectively.

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In the present work, we report that the manufacturing of new environmentally friendly and low-cost materials with electrical conductivity can be roughly and finely tuned by an external magnetic field for technical and biomedical applications. With this aim in mind, we prepared three types of membranes based on cotton fabric impregnated with bee honey, carbonyl iron microparticles (CI), and silver microparticles (SmP). In order to study the influence of the metal particles and the magnetic field on the electrical conductivity of membranes, electrical devices were made. Using the "volt-amperometric" method, it was found that the electrical conductivity of the membranes is influenced by the mass ratio (mCI: mSmP) and by the B values of the magnetic flux density. It was observed that in the absence of an external magnetic field, adding microparticles of carbonyl iron mixed with silver microparticles in mass ratios (mCI: mSmP) of 1:0, 1:0.5, and 1:1 causes the electrical conductivity of the membranes based on cotton fabrics impregnated with honey to increase 2.05, 4.62, and 7.52 times, respectively, compared with that of the membrane based on cotton fabrics impregnated with honey alone. When applying a magnetic field, the electrical conductivity of the membranes with microparticles of carbonyl iron and silver increases with increasing magnetic flux density B. We conclude that the membranes are very good candidates for the fabrication of devices to be used in biomedical applications due to the possibility of remote, magnetically induced release of the bioactive compounds from honey and silver microparticles into the area of interest during medical treatment.

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Silver-based materials have microbicidal action, photocatalytic activity and electronic properties. The increase in manufacturing and consumption of these compounds, given their wide functionality and application, is a source of contamination to freshwater ecosystems and causes toxicity to aquatic biota. Therefore, for the first time, we evaluated the toxicity of the silver tungstate (α-Ag2WO4), in different morphologies (cube and rod), for the microalga Raphidocelis subcapitata. To investigate the toxicity, we evaluated the growth rate, cell complexity and size, reactive oxygen species (ROS) production and chlorophyll a (Chl a) fluorescence. The α-Ag2WO4 - R (rod) was 1.7 times more toxic than α-Ag2WO4-C (cube), with IC10 and IC50 values of, respectively, 8.68 ± 0.91 µg L-1 and 13.72 ± 1.48 µg L-1 for α-Ag2WO4 - R and 18.60 ± 1.61 µg L-1 and 23.47 ± 1.16 µg L-1 for α-Ag2WO4-C. The release of silver ions was quantified and indicated that the silver ions dissolution from the α-Ag2WO4 - R ranged from 34 to 71%, while the Ag ions from the α-Ag2WO4-C varied from 35 to 97%. The α-Ag2WO4-C induced, after 24 h exposure, the increase of ROS at the lowest concentrations (8.81 and 19.32 µg L-1), whereas the α-Ag2WO4 - R significantly induced ROS production at 96 h at the highest concentration (31.76 µg L-1). Both microcrystal shapes significantly altered the cellular complexity and decreased the Chl a fluorescence at all tested concentrations. We conclude that the different morphologies of α-Ag2WO4 negatively affect the microalga and are important sources of silver ions leading to harmful consequences to the aquatic ecosystem.

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The paper presents experimental verification of customized resistive crack propagation sensors as an alternative method for other common structural health monitoring (SHM) techniques. Most of these are sensitive to changes in the sensor network configuration and a baseline dataset must be collected for the analysis of the structure condition. Sensors investigated within the paper are manufactured by the direct-write process with electrically conductive, silver-microparticle-filled paint to prepare a tailored measuring grid on an epoxy or polyurethane coating as a driving/insulating layer. This method is designed to enhance the functionality and usability compared to commercially available crack gauges. By using paint with conductive metal particles, the shape of the sensor measuring grid can be more easily adapted to the structure, while, in the previous approach, only a few grid-fixed sensors are available. A fatigue test on the compact tension (CT) specimen is presented and discussed to evaluate the ability of the developed sensors to detect and monitor fatigue cracks. Additionally, the ARIMA time series algorithm is developed both for monitoring and predicting crack growth, based on the acquired data. The proposed sensors' verification reveal their good performance to detect and monitor fatigue fractures with a relatively low measurement error and ARIMA estimated crack length compared with the crack opening displacement (COD) gauge.

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The objective of this paper is to evaluate and optimize the experimental parameters of the electro-deposition of silver atom nuclei on a graphite carbon paste to elaborate an electrochemical sensor. The electro-deposition process was performed using the cyclic voltammetry. The electrochemical studies show that the deposited silver micro-particle array offers an excellent electro-catalytic activity towards the NO2 attractor group of the dimetridazole side chain. SEM morphological analysis of the silver deposits indicates the presence of a large number of Ag micro-particles on the graphite carbon with good nucleation. The size of the Ag micro-particles is of the order of 19,7621 µm and their distribution is normal over the entire range of the pulp. DRX analysis of the deposit also indicates that the microcrystalline structure of the silver microcrystals in the deposit is face-centered cubic. The electrochemical behavior of dimetridazole is totally irreversible, the transfer process is controlled by diffusion phenomena on the surface of the electrode covered by a silver deposit realized µAg@CPE. The analytical performance of the constructed electrode shows a good selectivity. Calibration curves for the detection of dimetridazole have been drawn in the concentration range of 3,5 × 10-4 mol/L to 10-6 mol/L using cyclic voltammetry method, with a detection and quantification limits of 6.565 × 10-7 mol/L and 2.216 × 10-6 mol/L respectively. The applicability of the constructed electrode has been tested in real samples including orange juice, tomato juice, tap water. The results obtained show a recovery rate above 94%, which is very satisfactory.

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An accumulating body of evidence reports the synthesis and biomedical applications of silver nanoparticles. However, the studies regarding the use of maleic acid and citric acid in the synthesis of nano-sized silver particles (AgNPs) and micro-sized silver particles (AgMPs) as well as their antibacterial, antifungal, and anticancer activities have not been reported. In the current study, we synthesized AgNPs and AgMPs using maleic acid and citric acid as capping agents and have characterized them by UV-Vis, energy-dispersive X-Ray spectroscopy (EDS), X-Ray diffraction (XRD), and scanning electron microscope (SEM) analysis. The capped silver particles were examined for their antimicrobial activity and cytotoxicity against bacteria, fungi, and brine shrimp. Additionally, the anticancer activity of these particles was tested against human breast and liver cancer cell lines. The free radical scavenging activity of capped silver particles was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. SEM analysis revealed a round plate-like morphology of maleic acid capped particles with an average size of 39 ± 4 nm, whereas citric acid capped particles display flower-shaped morphology with rough surfaces and an average size of 250 ± 5 nm. The uncapped AgMPs were hexagonal with 500 ± 4 nm size. EDS and XRD analysis confirmed the presence of Ag and face-centered cubic crystalline nature, respectively. Functionally, capped silver particles exhibited antibacterial activity against Gram-positive (Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus) and Gram-negative bacteria (Salmonella setubal, Enterobacter aerogenes, and Agrobacterium tumefaciens). The bactericidal activity was more active against Gram-negative bacteria with minimum inhibitory concentration (MIC) as low as 5 ppm as compared to 25 ppm for Gram-positive. Similarly, the silver particles demonstrated antifungal activity by inhibiting the growth of five fungal strains (Mucor species, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, and Fusarium solani) up to 50% at the concentration of 500 ppm. Additionally, these particles showed substantial toxicity against brine shrimp and also significantly inhibited the proliferation of breast cancer (MCF7) and liver cancer (HePG2) cell lines (IC50 8.9-18.56 µM). Uncapped AgMPs were less effective, inhibiting only the proliferation of MCF7 cells with IC50 46.54 µM. Besides cytotoxicity, these particles acted as potential antioxidants, showing free radical scavenging up to 74.4% in a concentration-dependent manner. Taken together, our results showed that the modifiers affect the shape and size of silver particles and may, in part, contribute to the antimicrobial and antioxidant activity of silver particles. However, the contribution of maleic acid and citric acid in enhancing the antimicrobial, anticancer, and antioxidant potential independent of silver nano and microparticles needs to be studied further. In vivo experiments may determine the therapeutic effectiveness of silver particles capped with these modifiers.

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This study proposes the use of new materials based on core-shell structure magnetic microparticles with Ag0 (Ag(0)-MPs) on their surface to remove bromides and chlorides from waters intended for human consumption. Hydrogen peroxide was used as oxidizing agent, Ag(0)-MPs is thereby oxidized to Ag (I)-MPs, which, when in contact with Cl- and Br- ions, form the corresponding silver halide (AgCl and AgBr) on the surface of Ag-MPs. The concentration of Cl- and Br- ions was followed by using ion selective electrodes (ISEs). Silver microparticles were characterized by high-resolution scanning electron microscopy and X-ray photoelectron spectroscopy, while the presence of AgCl and AgBr on Ag-MPs was determined by microanalysis. We analyzed the influence of operational variables, including: hydrogen peroxide concentration in Ag-MP system, medium pH, influence of Cl- ions on Br- ion removal, and influence of tannic acid as surrogate of organic matter in the medium. Regarding the influence of pH, Br-and Cl- removal was constant within the pH range studied (3.5-7), being more effective for Br- than for Cl- ions. Accordingly, this research states that the system Ag-MPs/H2O2 can remove up to 67.01% of Br- ions and 56.92% of Cl- ions from water (pH = 7, [Ag-MPs]0 = 100 mg L-1, [H2O2]0 = 0.2 mM); it is reusable, regenerated by radiation and can be easily removed by applying a magnetically assisted chemical separation process.

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In this work, a new category of anionic Gemini surfactants with a rigid space, disodium 2,2'-(1, 4-phenylene bis (methylene)) bis (alkane-1-sulfate) (CmArCm, m=8, 10, 12, 14), were developed. They showed excellent surface activity and remarkable micellization tendency in aqueous solutions as measured by the equilibrium surface tension method. It was noticed that both the surface activity and micellization ability of CmArCm were gradually strengthened upon increasing the hydrophobic chain length m. Those Gemini surfactants were employed as capping reagents to fabricate three-dimensional (3D) hierarchical silver microparticles (AgMPs) successfully even in a large-scale of gram-level. The morphological evolution of these microparticles in different conditions was investigated systematically by various techniques including scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The possible formation mechanism of surfactant assisted AgMPs was also proposed. It was found that the morphology of AgMPs could be tailored from nut-like, lichi-like, to coral-like microparticles by simply varying the concentration of surfactant. However, the hydrophobic chain length m of CmArCm showed a little influence on the morphology of AgMPs. Moreover, the surface-enhanced Raman scattering of Rhodamine 6G results evidently confirmed the superior surface activity of synthesized AgMPs.