Scanning Electron Microscopy Energy-dispersive X-ray Analysis Research Articles

PolyCitrulline Modified Glassy Carbon Electrode as a Voltammetric Sensor for the Simultaneous Determination of Metabolic Syndrome Biomarkers-Uric Acid and Tyramine

Abstract This article describes the development of a simple and sensitive voltammetric sensor for the simultaneous determination of Uric acid (UA) and Tyramine (TYM), which act as metabolic syndrome (Mts) biomarkers. The electropolymer of the naturally occurring amino acid citrulline (Cit) has been employed as the electrode modifier in this sensor. Glassy carbon electrode modified with poly citrulline has been characterized with the aid of techniques such as scanning electron microscopy (SEM) and SEM-energy dispersive X-ray analysis, surface area calculations and electrochemical impedance spectroscopy. Studies were carried out to optimize parameters like the cycles of polymerisation, supporting electrolyte and its pH. The sensor which offers fast determination of the analytes using square wave voltammetry possesses a limit of detection 1.32×10-8 M and 4.20×10-8 M for UA and TYM, respectively. The applicability of the sensor in body fluids has been proved through spike recovery analysis in artificial blood serum and urine samples. Interference on the voltammetric signals created by some dominant coexisting species of the analytes was found to be tolerable.

Preparation of an adsorptive membrane of polyvinylidene fluoride incorporated functionalized boron nitride nanosheets for arsenic removal

Incorporating nanomaterials into membranes will enhance wastewater treatment efficiency with their unique characteristics, such as higher permeability, thermal stability, surface roughness, hydrophilicity, and fouling control. In this study, the surface modified boron nitride with phosphoric acid 2-hydroxyethyl methacrylate ester (PA/BN) was grafted with polyethylene glycol (PEG) via conventional grafting. The PEG grafted PA/BN (PEG-g-PA/BN) melt blended with polyvinylidene fluoride (PVDF) resin by using an internal mixer at different mass percentages (100% PVDF (PVDF), 3% PEG-g-PA/BN + 97% PVDF (97:3 BN), 5% PEG-g-PA/BN + 95% PVDF (95:5 BN), 7% PEG-g-PA/BN + 93% PVDF (93:7 BN), and 7% PEG-g-PA/BNNS + 93% PVDF (93:7 BNNS). Phase inversion technique was used to cast the blended mixture into a thin membrane. The prepared membranes were analyzed with different characterization techniques to determine chemical composition, crystallinity, morphology, and thermal properties. The prepared composite membrane was evaluated in terms of water permeability, anti-fouling resistance, and solute rejection efficiency with deionized water, bovine serum albumin, and arsenic solution as well. PVDF membranes show high water flux and porosity. The water flux and porosity of the blends decrease as the percentage of PEG-g-PA/BN increases. However, the highest removal capacity for arsenic was observed at 93:7 BN. The adsorption of arsenic ions takes place via complexation with PA/BN in the PVDF matrix. This was confirmed with field emission scanning electron microscopy–energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy analyses.

Sustainable and Novel Development of Metal Matrix Composite Using Scrap Aluminium Alloy Reinforced with Scrap Borosilicate Glass Particles by Stir Casting Technique

This study aims to achieve a sustainable and environmentally friendly approach to the development of metal matrix composites (MMCs) by utilizing locally available Scrap Aluminium Engine Heads (SAEH) as the matrix material and powdered Scrap Borosilicate Glassware (SBG) as reinforcement. The stir casting technique was employed for composite fabrication, combining the benefits of cost-effectiveness and ease of processing. The research evaluates the mechanical properties of the developed MMC, including tensile strength, compressive strength, hardness, and impact resistance. Physical properties such as density and porosity were also investigated, alongside microstructural analysis using optical microscopy, scanning electron microscopy (SEM), SEM energy-dispersive X-ray analysis (EDAX), and X-ray diffraction (XRD). The results demonstrate a significant improvement in the mechanical properties of the composite compared to the as-cast SAEH material. The ultimate tensile strength increased from 70.3 MPa for as-cast SAEH to 117.3 MPa for SAEH reinforced with SBG. Similarly, ultimate compressive strength improved from 513.7 MPa to 700.67 MPa, and hardness increased from 32.56 HRB to 43.33 HRB. Furthermore, the impact strength showed a notable enhancement, increasing from 1.4 Joules to 1.8 Joules. Importantly, the porosity percentage decreased from 14.28% in as-cast SAEH to 9.97% in SAEH+BS composites, indicating improved material density. This research contributes to the development of sustainable MMCs using recycled materials, offering enhanced mechanical properties and reduced environmental impact, making it valuable for various engineering applications. By aligning with Sustainable Development Goals (SDGs), this study addresses key sustainability targets and underscores the importance of environmentally responsible materials development in advancing global sustainability efforts.

Characterization and Eco-Friendly Synthesis of Silver and Iron Nanoparticles Using Microalgae Extracts: Implications for Nanobiotechnology.

<b>Background and Objective:</b> The remarkable surface-to-volume ratio and efficient particle interaction capabilities of nanoparticles have garnered significant attention among researchers. Microalgal synthesis presents a sustainable and cost-effective approach to nanoparticle production, particularly noteworthy for its high metal uptake and ion reduction capabilities. This study focuses on the eco-friendly and straightforward synthesis of Silver (AgNPs) and Iron (FeNPs) nanoparticles by utilizing Spirulina (<i>Arthrospira platensis</i>) and <i>Chlorella pyrenoidosa</i> extract, devoid of any chemical reducing or capping agents. <b>Materials and Methods:</b> Following the mixing of 1 mM AgNO<sub>3</sub> and 1 mM iron oxide solution with the algal extract, the resulting filtrated solution underwent comprehensive characterization, including UV-visible absorption spectra analysis, observation of particle morphology, Zetasizer measurements and Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX) analysis. <b>Results:</b> The UV-visible spectroscopy revealed a maximum absorbance peak at 430-440 nm, confirming the successful green synthesis of AgNPs and FeNPs, as indicated by the distinct color change from transparent to dark reddish-yellow and brown to reddish-brown, respectively. The SEM-EDX analysis further elucidated the spherical morphology of the nanoparticles, with an average diameter of 93.71 nm for AgNPs and 6198 nm for FeNPs. The Zeta potential measurements indicated average values of -56.68 mV for AgNPs and 29.73 mV for FeNPs, with conductivities of 0.1764 and 0.6786 mS/cm, respectively. <b>Conclusion:</b> The observed bioaccumulation of silver and iron nanoparticles within the algal extract underscores its potential as an environmentally friendly and cost-effective method for nanoparticle synthesis. These findings suggested a promising avenues for the application of silver and iron nanoparticles in the field of nanobiotechnology. Future research endeavors could focus on optimizing preparation conditions and controlling nanoparticle size to further enhance their utility and effectiveness.

Green Synthesis, Characterization, and Photocatalytic Activity of Zinc Oxide Nanoparticles on Photodegradation of Naphthol Blue Black Dye

Zinc oxide (ZnO) nanoparticles have been successfully synthesized using water extract of red dragon fruit (Hylocereus polyrhizus) stem with zinc acetate dihydrate as a precursor of ZnO. Chemical compounds contained in the red dragon fruit stem extract, such as phenolics, terpenoids, and steroids, acted as reducing agents, stabilizers, and capping agents. The phase structure, crystallite size, functional groups, shape, and morphology of ZnO nanoparticles were determined by X-ray diffraction (XRD), Fourier Transform infrared (FT-IR) Spectroscopy, and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX). The XRD pattern confirmed the crystallinity of synthesized zinc oxide was in the zincite (ZnO) phase with an average crystallite size of 79.09 nm. Spectroscopy FTIR analysis showed that the synthesized ZnO nanoparticles had characteristics similar to the ZnO standard/commercial. SEM-EDX analysis revealed that the synthesized ZnO nanoparticles were spherical, evenly distributed, and homogeneous particle size. The photocatalytic activity of synthesized ZnO nanoparticles was evaluated on the photodegradation of naphthol blue black (NBB) dye. The results showed that the synthesized ZnO nanoparticles have high photocatalytic activity that can degrade NBB dye up to 98.82%. This high photocatalytic activity was obtained at operating parameter conditions with the initial pH of NBB at 2, the dosage of ZnO nanoparticles at 250 mg, and the initial dye concentration at 10 ppm.

Sustainable fabrication of biogenic Fe–Zn nano core-shell and their photocatalytic efficiency against third generation antibiotics

The photocatalysis of third generation antibiotics was deliberated using biogenic iron oxide (FeO NPs) and iron-zinc (Fe–Zn) nano core-shell. Photocatalysts were prepared from aqueous extract of Adiantum incisum (Ai) by reacting with apposite salt solutions. FeO NPs were synthesized by mixing 5 % Ai extract with 5 mM FeSO4.7H2O at alkaline pH (50 °C). While Fe–Zn nano core-shell were synthesized by coating ZnO NPs on FeO NPs using successive reduction method. Synthesis and stabilization of nanoparticles were substantiated by diverse surface plasmonic resonance peak of FeO NPs and Fe–Zn nano core-shell at explicit wavelength ranges. Band gap energy values, Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), Raman and Scanning Electron Microscope (SEM) analysis validates that coating was done efficaciously. Fourier Transform Infrared Spectroscopy (FTIR) recognized the role of plant phytochemicals in NPs reduction and stabilization. SEM-Energy Dispersive X-Ray analysis (EDX) analysis unveiled that FeO NPs and core-shell aggregates are orbicular in shape. Average crystalline size of FeO NPs and Fe–Zn nano core-shell obtained from XRD was 15.64 nm and 22.94 nm respectively. The photocatalytic degradation of Ampicillin, Levofloxacin and Ceftriaxone under UV and Sunlight displayed that Fe–Zn nano core-shell have high degradation capability than FeO NPs. Degradation potential was higher in UV than in sunlight. Maximum degradation of Ampicillin (74.4 %) was attained under UV light and (60.31 %) in sunlight followed by Levofloxacin. Degradation was further confirmed by conducting FTIR analysis and antimicrobial studies. Gas Chromatography-Mass Spectrometry detected Hexadecenoic acid as the main degradation product in nano treated Ampicillin and Levofloxacin.

Efficacy of Chitosan Scaffolded Calcium Silicate-based Cements for Treating Internal Resorption Defects with Perforation: In Vitro Study.

The present study aimed to evaluate the efficacy of chitosan scaffold combined with calcium silicate cements in the management of internal resorption with perforation. Internal resorption cavities were simulated in 20 human permanent maxillary incisors that were then divided into two groups: group I - biodentine and group II - chitosan scaffold combined with biodentine. The samples were evaluated for the mineralization activity at the end of the 7th day and 14th day using scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis. The data were recorded, tabulated, and then statistically analyzed. From the SEM-EDX analysis, the mean score of calcium and phosphorus ion uptake by the material was obtained. Statistical analysis by nonparametric Mann-Whitney test showed that there was statistically significant difference in calcium ion uptake at the end of the 7th day (p = 0.016) and at the end of 14th day (p = 0.043) between the group biodentine and group chitosan scaffold combined with biodentine (p < 0.05). In this present study, the use of chitosan scaffolds combined with biodentine showed a statistically significant difference in the mineralization activity when compared with pure biodentine. These scaffolded biomaterials exhibited greater potential for mineralization in vitro which can be efficiently used for the management of teeth with internal resorption with perforation. Further clinical trials are required for the understanding of their behavior in real-world scenarios. Calcium silicate cements have often exhibited defective hard tissue barrier formation and hence there is a pressing need to search for newer biomaterials that can overcome these shortcomings. Scaffolded biomaterials provide a controlled microcellular environment for bioactivity, and they were found to be efficient in the remineralization of tooth structure. The present study findings indicate that these chitosan scaffolds can be efficiently used in combination with calcium silicate cements for the management of internal resorption with perforation to enhance the treatment outcome.

Remineralization Potential of a Novel Biomimetic Material (Self-assembling Peptide P11-4) on Early Enamel Caries: An In Vitro Study.

To assess the remineralizing potential of self-assembling peptide P11-4 and compare it to the remineralizing potential of fluoride varnish using DIAGNOdentTM, as well as the amount of mineral gain after application of fluoride varnish and self-assembling peptide P11-4. This study included 20 premolars extracted during orthodontic therapy with all surfaces intact and free of hypoplastic regions, white spot lesions (WSL) and dental caries. The teeth sample for Curodont RepairTM (self-assembling P11-4) and Bifluorid 10® (fluoride varnish) was equally divided. On each tooth surface, a 2 × 2 mm window was created. The samples were immersed in a demineralizing solution for 96 hours before being subjected to DIAGNOdentTM pen reading, ICDAS-II scoring, and scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) analysis on one half of the sample. The remineralizing agents were applied to the second half of the sample according to the manufacturer's instructions and placed in artificial saliva for 21 days, with the artificial salvia being replaced every 24 hours. After 21 days, the second half of the sample was subjected to DIAGNOdentTM pen reading, ICDAS-II score, and SEM-EDX analysis. Following remineralization, the DIAGNOdentTM pen and ICDAS-II score values differed statistically between the two groups, with the Bifluorid 10® group reporting higher mean values (p > 0.05) using t-test analysis. Energy-dispersive X-ray analysis using the t-test revealed a statistically significant result for remineralization (p < 0.05), with CurodontTM Repair group (55.150.84) reporting better mean values than Bifluorid 10® for phosphorus and calcium, but Bifluorid 10® reporting a higher result in remineralization (p < 0.05) than CurodontTM Repair for fluoride. CurodontTM Repair showed better remineralizing potential compared with Bifluorid 10® varnish. In terms of the mineral gain, CurodontTM Repair showed better results for calcium and phosphorus post-remineralization. Whereas Bifluorid 10® showed a higher gain in terms of fluoride. Self-assembling peptide P11-4 can be used as an alternative to fluoride varnish for remineralizing WSL. Self-assembling polypeptide P11-4 is a novel remineralizing agent for initial enamel lesions, which is the least-invasive method of enamel remineralization.

Pillarization of Sumatera Bentonite by Sodium-assisted As Effective Adsorbent of Anionic Surfactants Sodium Lauryl Sulphate (SLS) Waste

In this work, the Sumatera bentonite was sodium-pillarized in a new low-temperature and restricted time preparation route and then applied in anionic surfactant sodium lauryl sulphate removal. Structure characterization used Fourier Transform Infra Red (FT-IR), Scanning Electron Microscope - Energy Dispersive X-ray (SEM-EDX), X-ray Diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. A strong peak at 22° and 35.66° in XRD analysis was detected as Sodium-pillar that increased crystallinity, then the functional changes of dehydration in lattice structure were detected in 1013 cm−1 by FTIR analysis. The morphology and compositional transformation were analyzed by SEM-EDX and BET analysis, denoted by increasing particle shape and sodium intercalant composition homogeneity. Moreover, the surface area increased from 61.791 to 66.086 m2/g. The sodium lauryl sulphate adsorption by bentonite-Na reached maximum capacity at 8.403 mg/g, which is higher than the pristine bentonite (5.747 mg/g) under the optimum condition. The adsorption mechanism is feasible, endothermic, and conformed to the pseudo-second-order and Freundlich adsorption model. The new route proposed for sodium intercalation effectively improves the Sumatera bentonite adsorption ability to remove sodium lauryl sulphate waste. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Failure Analysis of Once-Through Steam Generator (OTSG) Tube

Abstract The once-through steam generator (OTSG) produces superheated steam using purified feed water. The plant-specific water quality, steam quality, high temperature, and pressure operations lead to the leakage of the OTSG tubes with economic, safety, and environmental consequences. Tube leakage is one of the most frequent causes of OTSG tube failure. A leaking tube was discovered within the OTSG unit of the 110 MW cogeneration plant. The failed section of the tube was removed from the steam generator. Several metallurgical examinations of this tube segment were performed to identify the failure mode and cause. A portion of the tube was analyzed using optical emission spectroscopy (OES) to determine the alloy composition. The results confirmed that the tubing was fabricated from a material consistent with chemical specifications for ASME Specification SB 407 Inconel Alloy 800 (UNS N08800). Glass bead blasting was used to determine the deposit-weight-density (DWD). The DWD value was a maximum of 5.1 g/ft2. The maximum internal deposit thickness was 0.002 in. No evidence of overheating was observed. Scanning electron microscope-energy-dispersive x-ray analysis (SEM-EDXA) was used to determine the elemental composition of the internal deposits. The results indicated that the internal gray deposits primarily comprised iron, chromium, and nickel compounds. There were also fewer amounts of sodium, silicon, aluminum, potassium, and calcium species. The subject tube failure involved a through-wall crack that occurred as stress corrosion cracking (SCC). Additions of caustic solution used in OTSG water treatment practices potentially induced corrosive substances into the tube.

Laser Application in Remineralisation of Enamel after Interproximal Reduction: An In-vitro Scanning Electron Microscopic Study

Introduction: Interproximal Reduction (IPR) or reproximation of enamel is of prime importance in orthodontics for correcting arch length-tooth size discrepancies. Despite its widespread application, IPR has been associated with adverse effects on the enamel surface. Aim: The aim of this study was to investigate whether laser application, when combined with fluoride application, enhances the remineralisation potential of enamel. Materials and Methods: This in-vitro study was conducted at Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, Tamil Nadu, India, from December 2021 to July 2022. It involved 54 extracted teeth, divided into three groups of 18 samples each. Reproximation of 0.25 mm was performed on the proximal enamel surface of each tooth. Group 1 served as the control, group 2 was subjected to Fluor Protector, and group 3 received low-level laser therapy (Er,Cr:YSGG) after Fluor Protector application. Fluor Protector (Ivoclar Vivadent) was applied for seven days. Following the seven-day fluoride administration, a laser treatment using 0.75 W of power and 8.5 J/cm2 of energy was applied for 20 seconds. Microhardness testing was conducted on the samples using a Vickers Hardness Tester. All specimens underwent surface topographic analysis with Scanning Electron Microscopy (SEM) and were evaluated for mineral content (% weight) using SEM-Energy Dispersive X-Ray analysis (EDX). Paired t-tests were performed to compare the pre- and post-microhardness values, while one-way Analysis Of Variance (ANOVA) test and Tukey’s Post-hoc test were used to compare the microhardness values between the groups. Results: The mean microhardness values recorded for group 1, group 2, and group 3 were 209.4±18.4 N/mm2 , 215.16±21.0 N/ mm2 , and 233±18.05 N/mm2 , respectively. ANOVA test revealed a significant difference in microhardness values between group 1 and group 2 (p-value=0.004), as well as between group 1 and group 3 (p-value=0.001). The microhardness value was highest for group 3, followed by group 2 post-intervention. SEM analysis showed that laser-treated enamel surfaces were smoother, with well-coalesced enamel rods. The porous structure of enamel was lost due to fluoride deposition in group 2 and group 3, resulting in a smooth surface. Conclusion: The combined application of fluoride and laser therapy demonstrated synergistic effects in remineralising the slenderised enamel. This simple, non-invasive technique may benefit patients undergoing IPR procedures by reducing the occurrence of dental caries.

ZnO-Enhanced Reduced Graphene Oxide Electrodes from Cocoa Shell: Nanoarchitectonics Platform for Photoelectrocatalytic Detection of Methylene Blue.

In this study, we report the successful preparation of reduced graphene oxide modified zinc oxide (rGO-ZnO) composites from cocoa shells. Synthesis of rGO-ZnO was carried out using the Hummer method and thermal reduction. The electrode material was comprehensively characterized using fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy & Energy Dispersive X-ray (SEM-EDX). The photoelectrocatalytic performance of the prepared composite electrodes was evaluated using various electrochemical techniques, including Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV), and Multi Pulse Amperometry (MPA). The FTIR analysis of rGO-ZnO exhibited distinct bands corresponding to C-O at 1022 cm-1, C=C at 1600 cm-1, and Zn-O at 455 cm-1. The XRD analysis revealed characteristic peaks at 26.6º, 29.2º, 36.2º, 44.04º, 47.58º, and 64.4º, confirming the presence of key crystalline phases. SEM-EDX analysis of rGO-ZnO revealed a rough surface morphology with bright white and black regions, signifying the coexistence of ZnO and rGO with carbon, oxygen, and zinc contents of 78.98%, 17.46%, and 3.56%, respectively. The investigations involved the photoelectrochemical profiles of methylene blue organic dyes at different concentrations, ranging from 0.5 ppm to 3.0 ppm. The acquired findings offer valuable understanding into the photoelectrocatalytic effectiveness of the composite electrodes containing rGO-ZnO, suggesting their potential use in potential scenarios involving the revitalization of the environment in industrial water systems.

Gross, ultrastructural, and histological characterizations of pecten oculi of the glossy ibis (Plegadis falcinellus): New insights into its scanning electron microscope-energy dispersive X-ray analysis.

The current study shows the first attempts to clarify the gross, ultrastructure, and histological properties of the pecten oculi of the diurnal, visually active glossy ibis, as well as scanning electron microscope-energy dispersive X-ray (SEM-EDX) image analysis (Plegadis falcinellus). The pecten oculi was found on the eyeball's posteroinferior wall, adjacent to the optic nerve in both the craniocaudal and posterio-anterior directions. The plicated quadrilateral black pigmented pecten oculi consisted of a base, 10-12 pleats, and an apex. The base was joined by an elevated ridge and derived from the non-vascular retina, while the apex was not a fused part and was found neighboring the gelatinous vitreous body. The limited interpleat spaces were somewhat wider at the base of the pecten oculi. The outer surface of each highly vascular pecten pleat revealed a tortious coiled formation due to the existence of a considerable number of capillary vessels. The outer pleat surfaces had a vitreopecteneal limiting membrane that segregated the pecten pleats from the vitreous body. The high SEM magnification revealed that there are considerable plentiful hyalocyte cells on the outer surface of the pleats. The SEM-EDX analysis of the elementary formatting of the pecten oculi (at apex, middle, and base) clarified that the carbon represents the highest and a half percent. Furthermore, oxygen represents one-third of all elemental composition in the three regions, while the lowest percentage is calcium. Finally, the pecten oculi characterizations of this migratory bird on the Northern Egyptian shore were associated with their adaptive dietary strategies.

The Synthesis and Characterization of Iron Sand-Based CuFe2O4 as Heavy Metal Ion Adsorbent

This study aimed to synthesize iron sand-based Copper Ferrite (CuFe2O4) using the coprecipitation method. The iron sand was taken from South Cianjur and used as a Fe cation source to synthesize CuFe2O4 nanoparticles. Three composition variations of CuCl2.6H2O and iron sand (Fe3O4) were employed, i.e., 1:1, 1:2, and 2:1. Samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy - Energy Dispersive X-Ray (SEM-EDX), and Atomic Adsorption Spectroscopy (AAS). The XRD analysis exhibits three synthesis-phase results: CuFe2O4, Fe2O3, and CuO. The produced CuFe2O4 has two crystal structures: t-CuFe2O4 in 1:2 variation and c-CuFe2O4 in variations 1:1 and 2:1. Adding Cu resulted in smaller crystal size and higher lattice parameters. SEM-EDX analysis of 1:2 sample variation showed a round-shaped particle of 102.57 nm. AAS analysis showed that the increased mole of Cu decreases the heavy metal, including Pb and Mn, adsorption capacity. The largest adsorption capacity was found in the 1:2 (60.698 mg/g).

A preliminary investigation into bacterial viability using scanning electron microscopy-energy-dispersive X-ray analysis: The case of antibiotics.

The metabolic stages of bacterial development and viability under different stress conditions induced by disinfection, chemical treatments, temperature, or atmospheric changes have been thoroughly investigated. Here, we aim to evaluate early metabolic modifications in bacteria following induced stress, resulting in alterations to bacterial metabolism. A protocol was optimized for bacterial preparation using energy-dispersive X-ray (EDX) microanalysis coupled with scanning electron microscopy (SEM), followed by optimizing EDX data acquisition and analysis. We investigated different preparation methods aiming to detect modifications in the bacterial chemical composition at different states. We first investigated Escherichia coli, acquiring data from fresh bacteria, after heat shock, and after contact with 70% ethanol, in order to prove the feasibility of this new strategy. We then applied the new method to different bacterial species following 1 h of incubation with increasing doses of antibiotics used as a stress-inducing agent. Among the different materials tested aiming to avoiding interaction with bacterial metabolites, phosphorous-doped silicon wafers were selected for the slide preparation. The 15 kV acceleration voltage ensured all the chemical elements of interest were excited. A thick layer of bacterial culture was deposited on the silicon wafer providing information from multiple cells and intra-cellular composition. The EDX spectra of fresh, heat-killed, and alcohol-killed E. coli revealed important modifications in magnesium, potassium, and sodium. Those same alterations were detected when applying this strategy to bacteria exposed to antibiotics. Tests based on SEM–EDX acquisition systems would provide early predictions of the bacterial viability state in different conditions, yielding earlier results than culture.

Effect of chloride penetration on electrical resistivity of CNT–CF/cement composites and its application as chloride sensor for reinforced mortar

This study was conducted to investigate the effect of chloride (Cl) penetration on the resistivity of highly conductive composites containing carbon nanotubes (CNTs) and carbon fibers (CFs). First, Cl ions were penetrated into the hardened composite specimens with the application of an electrical charge, and the profiles of the Cl contents, conductivity, hydration, and pore structures were then evaluated. Second, the composite sensors were embedded in a reinforced mortar and immersed in a NaCl solution. Third, the ion distribution in the composite sensor immersed in the NaCl solution was visualized via element mapping using a scanning electron microscopy–energy-dispersive X-ray analysis and an electron probe micro-analyzer. It was found that the resistivity of the composites increased as the Cl penetrated the specimens, and this phenomenon was presumably due to the clogging of the CNT network. The results indicated that the Cl penetration could be monitored by checking the trend of change in the resistance value of multiple sensors over time (trend analysis), and not just by measuring the instantaneous resistance value of a single sensor (deterministic measurement).

Doping of TiO2 Using Metal Waste (Door Key) to Improve Its Photocatalytic Efficiency in the Mineralization of an Emerging Contaminant in an Aqueous Environment

Photocatalysis is an effective advanced oxidation process to mineralize recalcitrant contaminants in aqueous media. TiO2 is the most used photocatalyst in this type of process. To improve the deficiencies of this material, one of the most used strategies has been to dope TiO2 with metallic ions. Chemical reagents are often used as dopant precursors. However, due to the depletion of natural resources, in this work it was proposed to substitute chemical reagents and instead use a metallic residue (door key) as a doping precursor. The materials were synthesized using the sol–gel method and calcined at 400 °C to obtain the crystal structure of anatase. The characterization of the materials was carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), scanning electron microscopy–energy-dispersive X-ray analysis (SEM-EDX) methods X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The results obtained indicate that Cu+/Cu2+ and Zn2+ ions coexist in the support, which modifies the physicochemical properties of TiO2 and improves its photocatalytic efficiency. The synergistic effect of the dopants in TiO2 allowed the mineralization of diclofenac in an aqueous medium when T-DK (1.0) was used as photocatalyst and simulated solar radiation as an activation source.

Pollution and Cleaning of PDMS Pervaporation Membranes after Recovering Ethyl Acetate from Aqueous Saline Solutions

The removal of volatile organic compounds (VOCs) from wastewater containing nonvolatile salts has become an important and interesting case of the application of the pervaporation (PV) process. The aim of this study was to evaluate the influence of salts on the PV removal of ethyl acetate from wastewater using a polydimethylsiloxane (PDMS) membrane. The fouled membrane was then characterized via scanning electron microscopy–energy-dispersive X-ray analysis (SEM–EDX) to investigate salt permeation. The membrane backflushing process was carried out by periodically flushing the permeate side of the tubular membrane. The results demonstrated that salts (NaCl and CaCl2) could permeate through the PDMS membrane and were deposited on the permeate side. The presence of salts in the feed solution caused a slight increase in the membrane selectivity and a decrease in the permeate flux. The flux decreased with increasing salt concentration, and a notable effect occurred at higher feed-salt concentrations. A permeate flux of up to 98.3% of the original flux was recovered when the permeation time and backflushing duration were 30 and 5 min, respectively, indicating that the effect of salt deposition on flux reduction could be mitigated. Real, organic, saline wastewater was treated in a pilot plant, which further verified the feasibility of wastewater PV treatment.

Unveiling the Complexity of Japanese Metallic Threads

In the framework of an extensive survey campaign on a collection of Japanese samurai armors, metallic threads from different parts of the traditional equipment were studied by several analytical techniques. The collection of armors belongs to Museo delle Culture (Lugano, Switzerland) and it is composed of ten elements, which date back from the 15th to 20th century. Metallic threads under study come from six of ten elements of the collection and represent a complex and unique multimaterial, which shows specific characteristics in Japanese tradition (kinran). The multianalytical approach based on ATR-FTIR (Attenuated Total Reflection-Fourier Transform Infrared) spectroscopy and SEM-EDX (Scanning Electron Microscopy, Energy Dispersive X-Ray) analysis, together with a careful observation with optical and digital microscopy, permitted to obtain a complete characterization of materials, which have shown a great variability in metal foils and in organic adhesives (urushi, animal glue, starch). Gold and silver turned out to be not so largely used as scholars thought, while aluminum showed a great diffusion. Within the collection of analyzed armors, the obtained results allowed us for the first time to get a complete comprehension of materials and techniques used by Japanese craftsmen, and to observe differences in the quality of the materials and in manufacture technology over the centuries.

Effects of decontamination protocols on the aesthetic, morphological, and material composition of preformed paediatric crowns

Preformed crowns (PCs) are exposed to potentially infectious bodily fluids during the trial fit; however, whether they can be safely re-used remains uncertain. This study determined the effects of decontamination methods on various PCs. The key criteria examined were aesthetic, morphological, and elemental characteristics. This is a laboratory-based experimental study. Stainless steel, pre-veneered stainless steel, and zirconia PCs underwent either: (a) ultrasonic cleaning with EmPower® followed by steam sterilisation, (b) thermal disinfection in an instrument washer with Asepti® Neutraliser/Asepti® followed by steam sterilisation, or (c) immersion in an ortho-phthalaldehyde (OPA) instrument-level disinfectant. The methods were performed for 1, 5, or 10 cycles, and scanning electron microscopy (SEM); red, green, and blue (RGB) value; and luminosity value were tracked (using a histogram of individual colour reference chips in Adobe Photoshop® ) to assess colour changes, and energy-dispersive X-ray (EDX) spectroscopy to characterise the material composition. Pre-veneered stainless steel crowns showed isolated zones of darkening with loss of luminosity and variations in green and blue values after ultrasonic or thermal washer disinfection combined with steam autoclaving at 5 and 10 cycles. No changes occurred with OPA. Both SEM imaging and EDX analysis identified no changes to crown materials from any of the three reprocessing methods. Reprocessing protocols need to reflect the differing responses of various types of PCs. Repeated steam sterilisation causes slight aesthetic alterations by way of colour instability and loss of luminosity to pre-veneered stainless steel crowns, but no issues with stainless steel or zirconia PCs.