Flotation-Spectrophotometric Method for the Determination of Aluminium ion Using Xylenol Orange

A simple, fast, reproducible and sensitive method for the flotation- spectrophotometric determination of Al3+ is reported. The apparent molar absorptivity (ε) of the ion associate was determined to be 8.35×104 L mol-1 cm-1. The calibration curve was linear in the concentration range of 1.0-50 ng mL-1 of Al3+ with a correlation coefficient of 0.9997. The limit of detection (LOD) was 0.621 ng mL. The relative standard deviation (RSD) at 10 and 30 ng mL-1 of aluminium were 1.580 and 2.410% (n=7) respectively. The method was applied for measuring the amount of aluminium in water samples

Cr(OH)(3)-NPs-CNC hybrid nanocomposite: a sorbent for adsorptive removal of methylene blue and malachite green from solutions

In this article, Cr(OH)₃ nanoparticle-modified cellulose nanocrystal (CNC) as a novel hybrid nanocomposite (Cr(OH)₃-NPs-CNC) was prepared by a simple procedure and used as a sorbent for adsorptive removal of methylene blue (MB) and malachite green (MG) from aqueous solution. Different kinetic models were tested, and the pseudo-second-order kinetic model was found more suitable for the MB and MG adsorption processes. The BET and Langmuir models were more suitable for the adsorption processes of MB and MG. Thermodynamic studies suggested that the adsorption of MB and MG onto Cr(OH)₃-NPs-CNC nanocomposite was a spontaneous and endothermic process. The maximum adsorption capacities for MB and MG were reached 106 and 104 mg/g, respectively, which were almost two times higher than unmodified CNC. The chemical stability and leaching tests of the Cr(OH)₃-NPs-CNC hybrid nanocomposite showed that only small amounts of chromium were leached into the solution.Farzin Nekouei, Shahram Nekouei, Farzaneh Keshtpour, Hossein Noorizadeh, Shaobin Wan

Fabrication of stable copper nanoparticles embedded in nanocellulose film as a bionanocomposite plasmonic sensor and thereof for optical sensing of cyanide ion in water samples

Herein, an optical plasmonic chemosensor was fabricated via in situ embedding of stable copper nanoparticles (Cu NPs) within flexible nanocellulose film (ECNPs-NC film) utilized for optical sensing of cyanide (CN⁻). Glycerol, as a plasticizer, was added to the nanocellulose suspension to improve ductility of nanocellulose-based film. In addition, to enhance the stability of Cu NPs against oxidizing and corrosion, the fabricated ECNPs-NC film was immersed and coated by benzotriazole solution. The Cu NPs were stable for 4 months. The fabricated ECNPs-NC film was characterized by various methods such as field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopic, dynamic light scattering, thermo-gravimetric analysis, and energy-dispersive X-ray spectroscopy. Analytical parameters influencing the efficiency of ECNPs-NC film fabrication were investigated and optimum conditions were stablished. The fabricated ECNPs-NC film was applied as a novel optical sensor for CN⁻ detection in water samples. By changing in CN⁻ concentration, surface plasmon resonance absorption intensity was changed and it was linear in the range of 0.25–0.40 µg mL⁻¹ with a detection limit of 0.015 µg mL⁻¹.Mehran Pouzesh, Shahram Nekouei, Mohammad Ali Ferdosi Zadeh, Farzaneh Keshtpour, Shaobin Wang, Farzin Nekoue

Direct transformation of waste printed circuit boards to nano-structured powders through mechanical alloying

Identifying a solution to directly transform waste printed circuit boards (PCBs) to useful alloys will save energy, conserve our valuable resources, and contribute to preservation of our environment. In this study a solid state mechanical alloying was used to directly convert waste PCBs to a homogenous nanostructured alloy (Cu79-Zn13-Fe3-Sn3-Ni1). Electron microscopy analysis showed 10 h milling time after a short period of cryomilling was enough to obtain a homogenous alloy and SAED ring pattern confirmed the nano-structure, although just a portion of particles size of the power was in nano-scale (< 100 nm). Lattice parameter, strain and grain size were calculated using XRD analysis. The grain size was 40 nm with a strain of 0.73%. High resolution XPS analysis confirmed minor surface oxidation of produced alloy. The UV–Vis analysis showed a broad peak between 350 and 650 nm indicating the chemical homogeneity of the surface. Also the calculation of input energy confirmed the formation of a nano-structured material during mechanical alloying. Finally, a promising application was investigated as nanofluid after dispersion of the synthesised powder in DI water followed by characterization of pH and conductivity variation. The conductivity of the sample was about 10 times higher than DI water. These results, for the first time, introduce a concept for directly transform waste PCBs to metallic alloys without using any heat or solutions

Prevalence and characterization of antimicrobial-resistant Escherichia coli in chicken meat from wet markets in Hong Kong.

Given the close contact between animals, animal products, and consumers in wet markets, fresh meat products are considered a potential source and disseminator of antimicrobial-resistant (AMR) bacteria near the end of the food chain. This cross-sectional study was conducted to estimate the prevalence of select AMR-E. coli in fresh chicken meat collected from wet markets in Hong Kong and to determine target genes associated with the observed resistance phenotypes. Following a stratified random sampling design, 180 fresh half-chickens were purchased from 29 wet markets across Hong Kong in 2022 and immediately processed. After incubation, selective isolation was performed for extended-spectrum β-lactamase producing (ESBL), carbapenem-resistant (CRE), and colistin-resistant (CSR) E. coli. The bacterial isolates were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Disc Diffusion was used to determine the susceptibility of ESBL- and CRE-E. coli isolates. The broth microdilution method was used to determine the minimum inhibitory concentration of CSR-E. coli. Targeted resistance genes were then detected by PCR. The prevalence of ESBL-E. coli and CSR-E. coli were estimated at 88.8% (95% CI: 83.4-93.1%) and 6.7% (95% CI: 3.5-11.4%), respectively. No CRE-E. coli isolate was detected. The blaCTX-M-1 gene was the most common β-lactamase group in isolated E. coli (80%), followed by blaTEM (63.7%); no blaSHV gene was detected. Forty-five percent of the isolates had blaTEM and blaCTX-M-1 simultaneously. The mcr-1 gene was detected in all 12 CSR isolates. Of 180 meat samples, 59 were from Mainland China, and 121 were locally sourced. There was no statistically significant difference in the prevalence of ESBL- and CSR-E. coli between the two sources. Our findings can be used to inform food safety risk assessments and set the stage for adopting targeted control and mitigation measures tailored to the local wet markets

Impact of quantized inter-agent communications on game-theoretic and distributed optimization algorithms

Quantized inter-agent communications in game-theoretic and distributed optimization algorithms generate uncertainty that affects the asymptotic and transient behavior of such algorithms. This chapter uses the information-theoretic notion of differential entropy power to establish universal bounds on the maximum exponential convergence rates of primal-dual and gradient-based Nash seeking algorithms under quantized communications. These bounds depend on the inter-agent data rate and the local behavior of the agents’ objective functions, and are independent of the quantizer structure. The presented results provide trade-offs between the speed of exponential convergence, the agents’ objective functions, the communication bit rates, and the number of agents and constraints. For the proposed Nash seeking algorithm, the transient performance is studied and an upper bound on the average time required to settle inside a specified ball around the Nash equilibrium is derived under uniform quantization. Furthermore, an upper bound on the probability that the agents’ actions lie outside this ball is established. This bound decays double exponentially with time