Advanced Ceramics Progress
Volume:8 Issue: 1, Winter 2022

Incorporation of CuO into ZnO contributes to the formation of CuO/ZnO composite, thus enhancing some properties of individual oxides such as antibacterial and photocatalytic activities. The current study evaluated the effect of both synthesis and in-situ syntheses of copper oxide on the zinc oxide particles using Copper(II) nitrate trihydrate as the starting material as well as acetic acid, D200, SHMP, PVP, CTAB, SDS, urea, and M2P surfactants. The impact of surfactants on the microstructure and chromatic properties of the samples was also investigated. The results from scanning electron micrographs showed different morphologies of copper oxide particles in the forms of needle, round, and flake depending on the type of surfactant. Moreover, the chromatic properties of the powders showed that the pigment synthesized in the presence of SHMP was in a better and darker black color than the others. Further, copper oxide powders exhibited more proper anti-bacterial behavior than the copper oxide/zinc oxide composite powders. In addition, copper oxide/zinc oxide particles had higher photocatalytic activity (up to 95 %) than copper oxide powders (about 65 %).

The current study aims to fabricate the HfB2-SiC-graphite composite through Spark Plasma Sintering (SPS) method at 1950 °C for 10 min. The oxidation behavior of the prepared composites was investigated at 1400 °C and different times of 4, 8, 12, and 16 h. In addition, the weight changes and thickness of the generated oxide layer were measured. The relative density, hardness, toughness, and strength of the composite made through the SPS method were calculated as 99.39 %, 10.16 GPa, 4.73 MPa.m1/2, and 464.12 MPa, respectively. The oxidation kinetic results of the composite exhibited linear-parabolic behavior. The chemical reaction during the oxidation process controlled the oxidation rate after 8 h. Followed by oxidation for more 12 h, the thickness of the oxide scale slowly increased, thus following a parabolic trend as a result of a decrease in the oxygen diffusion when HfOxCy and SiOxCy phases were formed. Therefore, it was concluded that the oxygen diffusion rate could control the oxidation process.

Scaffolds made of three components containing Gelatin (30.3-64.7 wt. %), Tragacanth (23.5-60.6 wt. %) and nano-Hydroxyapatite (9.09-11.67 wt. %) were fabricated through the freeze drying process. Among the scaffolds with the components in the mentioned range, three scaffolds were selected for comparison based on pre-test steps including washout and soaking in SBF for 28 days to evaluate their consistency. At the end, two scaffolds with the maximum and moderate wt. % of gelatin were selected for further studies. The same pre-tests were done to select one of the cross-linkers namely GPTMS, CaCl2, and Glutaraldehyde. As a result, GPTMS with the total amount of 10 % of the total polymers wt. % was selected as the cross-linker. The mechanical properties of the scaffolds were investigated through the compressive test, and the one with higher Gelatin content had the highest Elastic modulus. In addition, the biodegradability of the scaffolds was studied by soaking them in the PBS for 1, 3, 7, 14, 21, and 28 days and measuring the weight loss. Higher contents of Gelatin resulted in less degradation. In this research, the biocompatibility of the samples was surveyed by soaking them in the SBF for 1, 3, 7, 14, 21, and 28 days, and the formation of the apatite layer on the scaffold surface was studied using the XRD, FTIR, and SEM techniques. Of note, the apatite layer can be finely formed on the sample with moderate Gelatin content. Other two scaffolds with the maximum and minimum Gelatin contents were completely deteriorated in the SBF.

Investigation of the chemical compositions of pigments in glazed ancient ceramic tiles is of great importance from the monuments restoration point of view. In this regard, the current research aimed to investigate the chemical compositions and color charactristics of pigments in six glazed ancient ceramic tiles (Samples B1-B6) collected from Abdolazim Hasani Shrine (Safavid era), Ray, Iran. The results from X-ray Probe Micro Analyzer (XPMA), X-Ray Diffraction (XRD) patterns, and Energy Dispersive X-ray Spectroscopy (EDS) spectra revealed that the glazes were silica-based, containing 38.85 to 50.89 wt. % silicon in Samples B3 and B1, respectively, with lime, quarts, wollastonite, and cristobalite as the main phases. Raman spectroscopy also confirmed the presence of quartz, wollastonite, and tridymite along with chalk, gypsum, calcite, copper oxide, and green earth. The particle sizes of the pigments measured through Scanning Electron Microscopy (SEM) varied from 0.6 μm in Sample B1 to 5.5 μm in Sample B3. High intensity reflectance was also observed in the range of 490-560 nm, confirming the green color of the samples with different shades. In addition, CIE L*a*b* parameters clearly showed the correlation between the green color and concentration of Cu2+ ions within the silica-rich amorphous phase. Therefore, the presence of wollastonite, tridymite, and copper oxide in the samples under study was obviously indicative of presence of Egyptian green pigments in the glazes.

Large area fabrication of graphene, as a leading two-dimensional material as well as an allotrope of carbon, is a challenging requirement prior to its preparation for applications. Chemical Vapor Deposition (CVD) is one of the most effective and promising methods for high-scale and high-quality synthesis of graphene. In this study, graphene layers were grown on copper (Cu) sheets using low-pressure CVD technique at 930 °C, 870 °C, and 760 °C. Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Optical Microscopy (OM) and Atomic Force Microscopy (AFM) were employed in this study to investigate the effect of the process temperature on the structural properties, morphology, grain boundaries, continuity, purity, and number of layers. The results from analyses revealed that at higher temperatures, the continuity and quality of the layers and number of grain boundaries were higher and lower, respectively. In contrast, at lower temperatures, the nucleation and discontinuity of the deposited layers were relatively high. The surface roughness of the graphene sheets increased with a decrease in temperature.

Gene therapy is an attractive approach to treatment of diseases with genetic or non-genetic origins. This procedure is based on the delivery of genetic materials, mainly DNA or small interfering RNA (siRNA), to the target cells or tissues. Due to the presence of physical and chemical barriers in the internal environment and cells of the body such as degrading enzymes in the circulatory system or electrical charge of the cell membrane, transfection of the naked nucleic acids is inefficient. In order to overcome this problem, different types of gene transfer carriers were developed. Of note, nanoparticle-based carriers have attracted considerable attention owing to their particular properties. Nanoparticles (NPs) are available in different types, each with its own specific advantages and disadvantages. Some of their advantages such as their small size have made NPs a potential candidate for eliminating obstacles to the genetic material delivery. However, these NPs have several limitations. The current study aimed to introduce different types of NPs used in the delivery of genetic materials and examine the basic aspects of the fabrication, characterization, and functionalization of NPs. Further, it briefly summarized the advantages and disadvantages of each approach to gene delivery by means of NPs. Finally, it suggested some applications of the nanoparticle-based gene therapies in the clinical trials.