Direct binding and characterization of laccase onto iron oxide nanoparticles.

Iron oxide nanoparticles (IONPs) exhibit unique magnetic properties and possess a high surface-to-volume ratio, making them ideal candidates for the conjugation of substances, including enzymes. Laccase (EC 1.10.3.2), an oxidative enzyme with diverse applications, presents an opportunity for enhancing stability and reusability through innovative immobilization techniques, thus reducing overall process costs. In this study, we employed a direct binding procedure via carbodiimide activation to conjugate laccase onto IONPs synthesized using thermal chemical coprecipitation. Stabilization of the nanoparticles was achieved using thioglycerol and polyvinyl alcohol (PVA) as capping agents. Characterization of the synthesized nanoparticles was conducted using UV-spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy. FTIR spectroscopy analysis confirmed successful laccase binding to magnetic nanoparticles, with binding efficiencies of 90.65% and 73.02% observed for thioglycerol and PVA capped IONPs, respectively. Furthermore, the conjugated enzyme exhibited remarkable stability, retaining nearly 50% of its initial activity after 20 reuse cycles. This research demonstrates that immobilizing laccase onto IONPs enhances its activity, stability, and reusability, with the potential for significant cost savings and expanded applications in various fields.

Correlation between Magnetic and Dielectric Response of CoFe2O4:Li1+/Zn2+ Nanopowders Having Improved Structural and Morphological Properties.

The vast applicability of spinel cobalt ferrite due to its unique characteristics implies the need for further exploration of its properties. In this regard, structural modification at the O-site of spinel with Li1+/Zn2+ was studied in detail for exploration of the correlation between structural, magnetic, and dielectric properties of the doped derivatives. The CTAB-assisted coprecipitation method was adopted for the synthesis of the desired compositions owing to its cost effectiveness and size controlling ability. Redistribution of cations at T- and O-sites resulted in the expansion of the crystal lattice, but no distortion of the cubic structure was observed, which further supports the flexible crystal structure of spinel for accommodating larger Li1+/Zn2+ cations. Moreover, an XPS analysis confirmed the co-existence of the most stable oxidation states of Zn2+, Li1+, Co2+, and Fe3+ ions with unstable Co3+ and Fe2+ ions as well, which induces the probability of hopping mechanisms to a certain extent and is a well-established behavior of cobalt ferrite nanoparticles. The experimental results showed that Li1+/Zn2+ co-doped samples exhibit the best magnetic properties at dopant concentration x = 0.3. However, increasing the dopant content causes disturbance at both sites, resulting in decreasing magnetic parameters. It is quite evident from the results that dielectric parameters are closely associated with each other. Therefore, dopant content at x = 0.1 is considered the threshold value exhibiting the highest dielectric parameters, whereas any further increase would result in decreasing the dielectric parameters. The reduced dielectric properties and enhanced magnetic properties make the investigated samples a potential candidate for magnetic recording devices.

Record-High Thermoelectric Performance in Al-Doped ZnO via Anderson Localization of Band Edge States.

Oxides are of interest for thermoelectrics due to their high thermal stability, chemical inertness, low cost, and eco-friendly constituting elements. Here, adopting a unique synthesis route via chemical co-precipitation at strongly alkaline conditions, one of the highest thermoelectric performances for ZnO ceramics ( P F max = $PF_{\text{max}} =$  21.5 µW cm-1 K-2 and z T max = $zT_{\text{max}} =$  0.5 at 1100 K in Zn 0.96 Al 0.04 O ${\rm Zn}_{0.96} {\rm Al}_{0.04}{\rm O}$ ) is achieved. These results are linked to a distinct modification of the electronic structure: charge carriers become trapped at the edge of the conduction band due to Anderson localization, evidenced by an anomalously low carrier mobility, and characteristic temperature and doping dependencies of charge transport. The bi-dimensional optimization of doping and carrier localization enable a simultaneous improvement of the Seebeck coefficient and electrical conductivity, opening a novel pathway to advance ZnO thermoelectrics.

Enhanced Coarse-Grained WC-Co(Ce) Cemented Carbide Prepared through Co-Precipitation.

The exploration of coarse-grained WC cemented carbide has become a research hotspot for its application in the fields of rock cutting and mining; a key issue is how to achieve uniform dispersion and densification of the sintered phase, as well as how to obtain better mechanical properties. In this paper, chemical co-precipitation, combined with hydrogen reduction, was adopted. CoCl2·6H2O and CeCl3 were used as precursors to coat Co nanoparticles on the surface of WC powder while introducing different contents of cerium; the samples were then sintered and densified to obtain WC-Co(Ce) hard alloy materials. On the surface of the obtained WC particles, the distribution of Co(Ce) nanoparticles was uniform and dense, and the average particle size after sintering was 4.2 µm, which lies in the coarse-grained range. The addition of cerium elements significantly improves the flexural strength and impact toughness; when the cerium content was 0.5% and 0.6%, they increased to 2487 MPa and 36.1 kJ/m2, respectively. The addition of Co(Ce) through the co-precipitation method could achieve a uniform coating of the Co phase, along with the uniform dispersion and densification of the sintered phase, giving the WC-Co(Ce) cemented carbide excellent properties.

Magnetic ferrite nanoparticles coated with bovine serum albumin and glycine polymers for controlled release of curcumin as a model.

To conquer the low water solubility and bioavailability of curcumin (CUR), to corroborate its functional qualities and to broaden its applicability in the pharmaceutical sector, numerous nanoscale methods have been widely exploited for its administration. Because of its polycystic, biodegradable, biocompatibility, non-toxicity, and non-allergenic properties, bovine serum albumin (BSA) and glycine (Gly) have been actively investigated as natural biopolymers for decades. Various BSA and Gly-based nanocarriers with unique features for CUR delivery, such as magnetic ferrite nanoparticles, are being developed (MNPs). In this work, magnesium ferrite (MgFe2O4)/BSA and nickel ferrite (NiFe2O4)/Gly nanocomposites loaded with CUR (drug model) were manufactured for the first time using a chemical co-precipitation approach to create biocompatible drug nanocarriers. It was found that the synthesized MgFe2O4/BSA and NiFe2O4/Gly nanoparticles have a uniform particle distribution and their size is much less than 100 nm. Saturation magnetization in MgFe2O4 and NiFe2O4 reaches 13.07 and 33.4 emu/g the remarkable peak of magnetization decreases to 10.99 and 32.36 emu/g after the addition of polymers. These analyses also showed the presence of chemical bonds in the structure of the nanocomposite. The curcumin diffusion process in NPs were determined using a mathematical modeling. The yielding of the product for MgFe2O4/BSA and NiFe2O4/Gly in 200 h is about 72 and 63%, respectively. Also, regressed relative diffusivities (D/R2), including effective steric hindrance, were determined as 5.75 × 10-4 and 2.72 × 10-4 h-1 for MgFe2O4/BSA and NiFe2O4/Gly, respectively. It shows that there is a significant steric barrier that significantly deviates from the molecular diffusion of the liquid. As a result, the low effective release of curcumin in the particles is more noticeable. Our study demonstrated the effective relationship between the polymer architecture and the biophysical properties of the resulting nanoparticles and shed light on new approaches for the design of efficient NP-based drug carriers.

Synthesis and Characterization of the CaTiO3:Eu3+ Red Phosphor by an Optimized Microwave-Assisted Sintering Process.

The synthesis process has a significant influence on the properties of Ca1-xTiO3:Eu3+x phosphors; thus, an optimized process will lead to a better performance of the Ca1-xTiO3:Eu3+x phosphors. In this work, the feasibility of synthesizing the Ca1-xTiO3:Eu3+x phosphor with a good luminescent performance by combining the chemical co-precipitation method and microwave-assisted sintering was studied. The precursor of Ca1-xTiO3:Eu3+x phosphors were prepared by the chemical co-precipitation method. To find an optimized process, we applied both of the traditional (furnace) sintering and the microwave-assisted sintering to synthesize the Ca1-xTiO3:Eu3+x phosphors. We found out that a sintering power of 528 W for 50 min (temperature around 950 °C) by a microwave oven resulted in similar emission intensity results compared to traditional furnace sintering at 900 °C for 2.5 h. The synthesized Ca1-xTiO3:Eu3+x phosphors has an emission peak at 617 nm (5D0→7F2), which corresponds to the red light band. This new synthesized method is an energy efficient, time saving, and environmentally friendly means for the preparation of Ca1-xTiO3:Eu3+x red phosphor with good luminescent performance.

Preparation of Magnetic g-C3N4/Fe3O4 Composite and Its Application in the Separation of Catechol from Water.

Catechol has strong toxicity and deformity as well as carcinogenicity, and it is difficult to degrade naturally. Therefore, it is of great practical significance to develop efficient adsorbents to separate catechol from water quickly and effectively. In this work, g-C3N4/Fe3O4 magnetic nanocomposites were prepared using g-C3N4 as the matrix by chemical co-precipitation, mixing with Fe2+ and Fe3+ solutions. Then, g-C3N4/Fe3O4 was used, for the first time, as an adsorbent to investigate the removal rate of catechol under different conditions by the magnetic field separation method. The adsorption parameters of the g-C3N4/Fe3O4 nanocomposite were evaluated by the Langmuir and Freundlich adsorption models. The results showed that the g-C3N4/Fe3O4 nanocomposite presented a two-step adsorption behavior and a considerably high adsorption capacity. The removal rate of catechol reached 70% at the dosage of 50 mg, adsorption time of 30 min, and pH value of 6. Five adsorption-desorption cycles demonstrated that the g-C3N4/Fe3O4 material had good stability and reusability.

Study of photocatalytic activity of ZnS quantum dots as efficient nanoparticles for removal of methyl violet: effect of ferric ion doping.

Zinc sulfide quantum dots (QDs), as pure and doped with Fe(3+), were prepared for photodecolorization of methyl violet (MV), as a model dye, under UV light irradiation. The syntheses of QDs were carried out using a simple chemical co-precipitation method. The prepared samples were characterized by various techniques including X-ray diffraction, transmission electron microscopy, UV-Vis spectrophotometry and flame atomic absorption spectroscopy. The influences of operational parameters on the decolorization of MV such as dopant content, pH, dosage of nanophotocatalyst, UV irradiation time and initial dye concentration were studied. The results showed that the QDs presented high efficiency for MV decolorization, and doping of ZnS QDs with Fe(3+) enhanced the efficiency and rate of dye removal. Finally, the reproducibility and kinetic model of the dye degradation were discussed.

Study of characteristics of zirconia toughened glass infiltrated nanometer-ceramic composite powder(Al_2O_3/nZrO_2) / 实用口腔医学杂志

Objective: To investigate the properties of zirconia toughened glass infiltrated nanometer-ceramic composite (Al 2O 3/nZrO 2) . Methods: Zirconia toughened glass infiltrated nanometer-ceramic composite(Al 2O 3/nZrO 2)powder was prepared with combination of chemical co-precipitation method and ball milling. The shape, size, partical distribution, crystal phase and chemical composition were measured and analyzed. Results: (1) The crystal phase composition of the studied nanometer ceramic composite powder was made up with ?-Al 2O 3, t-ZrO 2 and m-ZrO 2 examined by XRD?(2) The density of the powder was 4.12 g/cm 3?(3) The particle distribution of the powder ranged 0.02～3.0 ?m?(4)Observed with SEM, the particle profile of the powder was regular, the ratio of length and width of the particles was about 1.2. Conclusion: The studied nanometer ceramic composite powder owns good homogeneity, stable chemical composition, reasonable powder-size gradation and may be favourable in the improvement of the packing density of ceramics.