Abstract

Drug-resistant pathogens are the primary factor contributing to morbidity and mortality worldwide. Nanoparticles present a promising technique for improving the effectiveness of drugs and creating efficient carriers for drug delivery. During the period from October-2022 and January-2023, thirty isolates of Staphylococcus haemolyticus, fifty five isolates of Staphylococcus epidermidis, twenty isolates of Proteus mirabilis, and thirty-three isolates of Pseudomonas aeruginosa, were collected from urine samples that taken from the microbiology laboratory at Medical City Hospital in Baghdad/Iraq. The isolates were diagnosed by conventional diagnosis methods, and then the diagnosis was confirmed using the VITEK2 system. In the present study, titanium dioxide nanoparticles (TiO2NPs) were successfully synthesized via the chemical and green method, and loaded with different antibiotics, to improve the treatment schemes as an alternative solution against multi drug resistant isolated bacteria. The prepared TiO2NPs were characterized by Fourier Transform Infrared spectroscopy (FTIR). The crystalline structure of TiO2NPs have been revealed by X-ray diffraction (XRD). The Field Emission Scanning Electron Microscope (FESEM) has shown a spherical shape with a size range of 24.97 to 56.58nm, and 23.85 to 31.58nm for chemically and greenly TiO2NPs, respectively. Atomic Force Electronic Microscopic (AFM) showed the average diameter of nanoparticles which obtained at 36.52nm, and 39.44nm for chemically and greenly TiO2NPs, respectively. The results of the Zeta potential of chemically TiO2NPs were at +17.48mV and greenly TiO2NPs at -22.09mV. All type of prepared TiO2NPs and Quercus infectoria extract were tested for antibacterial effect, the results showed the chemically TiO2NPs have an excellent antibacterial activity on S. haemolyticus and P. mirabilis. As for S. epidermidis and P. aeruginosa bacteria, the greenly TiO2NPs shows higher inhibitory effect than chemically and commercially TiO2NPs. The Q. infectoria extract exhibits a weak effect on Gram-negative bacteria, but only at high concentrations. The lowest antibacterial activity in this study was noticed against P. aeruginosa with zone-inhibition values of 17.00±2mm at100gmL-1 for commercially TiO2NPs. The combination of TiO2NPs with antibiotics was also examined for its synergistic effect, most of the results on the growth of MDR bacteria isolates showed an increase in the diameters of the inhibition zone for tested antibiotics. Summary II The Minimum Inhibitory Concentration (MIC) of TiO2NPs and plant extract was measured, these results indicate that the MIC of chemically, commercially, and greenlysynthesized TiO2NPs for P. mirabilis bacteria were lower than other tested bacteria at (1.56, 3.12, and 12.5)gmL-1 concentrations, respectively. The lowest MIC values were mostly obtained for the commercially TiO2NPs which showed high antibacterial activity with a significant decrease in the MIC compared to others. The microplate reader method was used to study TiO2NPs forms' ability to inhibit biofilm formation. The strongest inhibition effect for Gram-positive bacteria was obtained by chemically TiO2NPs, while in Gram-negative bacteria, the greenly TiO2NPs showed the highest impact of anti-biofilm activity against P. aeruginosa at (100%). The antioxidant potentials of TiO2NPs and plant extract were tested via their 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability (25, 50, 100, 150, 200)gmL-1 . The chemical TiO2NPs showed stronger scavenging activity than other tested materials. Our study proved that the preparation of TiO2NPs by Quercus infectoria extract and chemically method has high clinical potential for prospective use as an antibacterial agent.

Refractories are non-metallic materials with the ability to resist environments that are exposed to a temperature of 1500◦ C, because of their distinctive chemical and physical properties. These properties depend on the characteristics of raw materials and formulations (chemical and mineralogical composition, particle size and shape distribution) the forming process and the firing temperature. Refractory ceramics were prepared from Silicon Carbide (SiC) as a main phase bonded with a different weight percentages of Iraqi White Kaolin (20, 40, 60 and 80 wt%). After that, two weight percentages of micro size of alumina (5, 10 wt%) and one weight percentage of nano size of alumina (5 wt%) were added to all SiC-Kaolin mixtures. The samples were shaped by the axial pressing method after mixing well, then dried and fired at 1300° C. The physical, mechanical, thermal, and structural properties were measured such as (apparent porosity, water absorption, apparent density, loss in mass, and linear shrinkage), (Weibull modules), (thermal conductivity, thermal shock and heat capacity), and structural properties (scanning electron microscope SEM, X-Ray diffraction and atomic force microscope AFM). The tests conducted for refractory ceramic before and after add micro and Nano Alumina. When the kaolin ratio is 80% without adding micro and nano Al2O3 lead to reduce the apparent porosity and water absorption from 30.17 to 17.95 % and from 16.31 to 7.07 % respectively while occurred increasing in apparent density, loss in mass and linear shrinkage from 1.85g/cm3 to 2.54g/cm3 , from 1.21% to 7.77% and from 1.54% to 3.34%. respectively It was noticed that thermal conductivity decreasing with increasing of XVII kaolin ratio from 35 w/m.k to 13 w/m.k and the specific heat capacity increased with increasing kaolin clay from 300 j/kg.k to 700 j/kg.k . But adding the Micro Alumina in ratio 10% led to decrease in apparent porosity to 9.443wt% also water absorption reduction to 3.55wt%, as well as addition Nano Alumina in ratio 5wt% led to decrease apparent porosity to 8.11wt% and water absorption to 8.63wt%. Apparent density with added micro alumina increasing to 2.66g/cm3 , also increases loss mass to 25.06 %, and an increase in linear shrinkage to 8.40 %.The outcome showed that the inclusion of micro and Nano Alumina addition improved the refractory efficiency due to its high melting point. It is particularly well suited to difficult applications where the refract. Thermal conductivity decreased from 35 to 15 W/m.K. at 80 wt % of Kaolin addition. Adding micro Al2O3 with a ratio of 10% led to thermal conductivity reduction from 15 to 12 W/m.K. Thermal shock resistance results showed high shock resistance properties, as the product retained its properties and no breakage occurred in the specimens. It is clear from the images SEM that the porosity decreases when adding micro and nano alumina, due to the nano and micro alumina particles filling the space between SiC and Kaolin particles, then between other phases, which reduces the pores. Nano alumina is the most efficient due to the small size of the nanoparticles, and the homogeneity of the distribution, so it penetrates efficiently into the refractory body. AFM showed that the Adding 80wt% Kaolin without add alumina leads to reducing the surface roughness, average grain size diameter and Root main square (RMS)nm from 210.9nm to 93.30nm, from 814.175nm to 509.3nm and from 377.0 to 100 nm. Respectively Adding micro and Nano Al2O3 with ratio 5wt% lead to reduce the the surface roughness, average grain XVIII size diameter and Root main square (RMS)nm for Micro alumina from 93.30 nm to 84.06nm, from 509.3 to 498.9 nm and from 100 to 87.15 nm. Also for Nano alumina from 93.30 to 35nm, from509.3 to 498.9nm and from 100 to 41.8 nm. Throw the Weibull modules, the result showed that The optimal values for the prepared specimens in terms of specimen homogeneity and the best mechanical properties were for the mixtures composed of a wight percentage of: 20 kaolin, 80 silicon carbide and 5 wt% nano alumina.