In this contribution, the biochemical characterization of enzyme-like nanosilvers was performed toward nanozyme-catalyzed oxidation reactions. In this regard, silver nanoparticles were synthesized via a simple chemical reduction method and then characterized by the TEM imaging method. Afterward, their enzyme-like activity was investigated toward catalysis of the oxidation reaction of 3,3’,5,5’-tetramethyl-benzidine (TMB) as one of the most popular peroxidase substrates. The results exhibited a specific nanozymatic activity as high as 5400 nM min⁻¹ for the as-synthesized nanosilvers toward TMB oxidation. Due to the high enzyme-like activity of the as-prepared nanosilvers, their biochemical properties including pH, thermal, light, and shelf stability were characterized to explore more precisely describing their nanozymatic behavior. The results of thermal and pH stability studies showed that the as-prepared nanosilvers reveal their maximal enzyme-like activity at a wide temperature range of 25 ℃–35 ℃ and a pH range of 3.5–4.5, in order. Regarding the light stability and shelf-life studies, the results exhibited that 75% and 96% of the enzyme-like activity of the as-prepared nanozymes was saved after 7 days exposing visible light and 10 days of storage at 4 ℃ under dark conditions, in order.

Despite the well-known concepts on the intrinsic peroxidase-like activity of MnO₂ nanoparticles, up to date, their biochemical and kinetics characteristics were not investigated, especially, the current information about their performances toward n-electron oxidation of 3, 3′-diaminobezedine for producing indamine polymers is on limitation. Therefore, herein, the MnO₂ nanoparticles were synthesized by a simple low-cost co-precipitation method and then characterized by XRD, SEM, and DLS analysis. Besides, their peroxidase-like activity was evaluated upon standard peroxidase enzyme assay, revealing high intrinsic peroxidase-like activity for the as-mentioned MnO₂ nanozymes. Considering their high intrinsic peroxidase-like activity, their optimal biochemical characteristics were quantified by probing the progress of n-electron irreversible oxidation of 3, 3′-diaminobezedine in the presence of MnO₂ nanozymes as peroxidase mimics. The maximal activity of the as-mentioned MnO₂ nanoparticles with high intrinsic peroxidase-like activity was observed when the pH and temperature of the reaction media were fixed over 3.0–6.0 and 23 ℃–25 ℃, in order, revealing very high pH and thermal stability of the as-prepared nanoparticles. The salt stability of these nanoparticles was also checked using NaCl as model salt, revealing that the nanozymatic activity was stable over a salt concentration as high as 3–7 M. In addition, the affinity constant (K_m) and maximum velocity of the nanozyme-catalyzed oxidation of 3, 3′-diaminobezedine were found to be 1.6 mM and 47 nM sec⁻¹, in turn.

In this study, Zr-doped HfO₂ (HZO) based resistive random-access memory (RRAM) device were fabricated. The Hf:Zr (1:1) ratio in the HZO films were controlled by changing the HfO₂ and ZrO₂ cycle ratio during the atomic layer deposition (ALD) process. Next, we studied the structural and electrical properties of the Au/HZO/TiN RRAM device structure. The RRAM devices exhibits an excellent resistance ratio of the high resistance state (HRS) to the low resistance state (LRS) of ~10³ A, and as well as good endurance (300 cycles) and retention (>10³ s), respectively. Further, the device showed different conduction mechanism in LRS and HRS modes. The lower biased linear region is dominated by ohmic conductivity, whereas the higher biased nonlinear region is dominated by a space charge limited current conduction. This device is suitable for application in future high-density nonvolatile memory RRAM devices.

The article discusses the possibility of obtaining a hardened composite material with a structure of different porosity based on nanostructured hydroxyapatite synthesized by precipitation from solution. In this work, mechanochemical synthesis of composite materials based on hydroxyapatite was carried out in a vibrating mill with simultaneous mixing and grinding of initial components and property-modifying additives (Si, Al, Zr, SiO₂, Al₂O₃, ZrO₂, 10–20 wt.% each) followed by annealing in the temperature range 200 ℃–1000 ℃. The synthesized samples were certified using modern physico-chemical methods of analysis. The influence of the qualitative and quantitative composition of the composite on the sintering processes, porosity, strength characteristics, degree of dispersion and morphology of the studied samples was shown. The peculiarities of chemical interaction of hydroxyapatite with reinforcing additives during heat treatment, the effect on grain size, and changes in the properties and structure during annealing were revealed. The effect of the phase composition and the amount of introduced additives on the strength characteristics of the investigated samples was shown. The optimum amount of reinforcing additives providing the production of a dense and strong composite material was determined.

This study elucidates influence of silver (Ag) nanoparticles (NPs) on ac-conduction properties within the super conductive phase of Cu_0.5Tl_0.5Ba₂Ca₂Cu₃O_10−δ (CuTl-1223). The Ag NPs were prepared by sol-gel method and CuTl-1223 superconducting phase was prepared by conventional solid-state reaction method. The different weight percentages (wt.%) of Ag NPs were mixed with CuTl-1223 superconducting matrix in order to obtain (Ag)_x/CuTl-1223; x = 0 ~ 4.0 wt.% nanoparticles-superconductor composites. Complex impedance spectroscopy (CIS) and complex electric modulus spectroscopy (CEMS) were conducted to probe the impact of Ag NPs addition along the grain-boundaries of the bulk CuTl-1223 superconducting matrix and on the resistive and capacitive contributions to the total impedance at different T (K) and f (Hz) values.