ZIRCONIUM dioxide, commonly known as zirconia, is an interesting material and is receiving growing attention due to its excellent mechanical properties. The solid was characterized for surface area measurements, scanning electron microscopy (SEM), Energy dispersive X-ray diffractometry (EDX) and potentiometric titrations. Surface titrations were carried out at the temperature range 303 to 323K in the presence of different concentrations (0.1, 0.01 and 0.001mol/dm3) of NaNO3 as a background electrolyte. Surface charge density and point of zero charge (PZC) of ZrO2 were determined from the titration data. Salt addition method was also applied to measure the PZC of the solid. The surface charge densities of ZrO2 were observed to increase with increase in temperature but decrease while increasing the concentration of electrolyte. Further, the PZC was found to decrease with the rise in temperature. However, it was found to increase with increase in concentration of the background electrolyte. The thermodynamic parameters such as DH and DS were also determined from the slope and intercept of the linear plot of (pHpzc – 1/2 pKw) versus reciprocal temperature (1/T). The values of both the DH and DS were found to be negative, while that of DG were positive. From these thermodynamic parameters, it was suggested that the protonation / de-protonation process of ZrO2 is non-spontaneous.

Introduction: Particular characteristics of 89 Zr to produce various labeled compounds are crucial for developing radioimmunopharmaceuticals for clinical trials. This study aimed to produce 89 Zr for radiolabeling purposes as radioimmunoPET grade precursor. Methods: The computational calculations for 89 Zr production via 89 89 Y(p, n) Zr reaction were performed using TALYS-1. 8 and ALICE-91. 89 Zr was produced by the proton bombardment of the yttrium pellet using a 30 MeV cyclotron. ZR resin was used for the separation of 89 Zr from the target. The radionuclidic purity was assessed by a high purity germanium detector. The inductively coupled plasma spectrometry and instant thin layer chromatography methods were considered for chemical and radiochemical purity assessments, respectively. The biodistribution of [89Zr]Zr-oxalate was studied in Wistar rats by both sacrification and imaging. [89Zr]Zr-DFO-trastuzumab was produced as a proof of concept for a radioimmunoPET labeling. Results: Considering the cross-section of 89 89 Y(p, n) Zr reaction, 14 MeV proton energy was selected for 89 Zr production, while the yttrium pellet target was irradiated at least for 125 µ, Ah, . 89 Zr was finally prepared with a yield of 25. 9±, 1. 48 MBq/µ, Ah, a specific activity of 344. 1 MBq/µ, g, the radionuclidic and radiochemical purity higher than 99. 99% and 99%, respectively. Total amount of the metal ions in the final solution was less than 0. 1 ppm. Biodistribution of [ 89 Zr]Zr-oxalate demonstrated high accumulation in the bone, lungs, and heart. 89 [ Zr]Zr-DFO-trastuzumab was produced with a radiochemical purity higher than 99% and specific activity of 74 GBq/g in about 2 hours. Conclusion: [89Zr]Zr-oxalate was produced with suitable activity and high purity for the preparation of the radioimmunopharmaceuticals.

Modification of sodium montmorillonite was conducted using ZIRCONIUM phosphate. The effect of a series of phosphate precursors such as dihydrogen phosphate, diammonium hydrogen phosphate, and sodium phosphate was observed. The catalyst was used in the conversion of methanol dimethyl ether using 1 g of catalyst at a temperature range of 150-350 ˚, C with a Liquid Hourly Space Velocity (LHSV) monitored to 2. 54 h−, 1 and N2 as carrier gas. The product was analyzed directly with a reactor system connected to gas chromatography. The X-ray diffraction (XRD), Scanning electron microscope-energy dispersive X-ray (SEM-EDX), N2 adsorption-desorption, and Temperature-programmed desorption of ammonia (NH3-TPD) were utilized to characterize the catalyst. The characterization showed that the modified sodium montmorillonite-ZIRCONIUM phosphate was successfully synthesized. The study showed that modified montmorillonite using ZIRCONIUM phosphate significantly increased the catalytic activity of sodium montmorillonite by providing medium and strong acid sites also increased the surface area. The modified sodium montmorillonite-ZIRCONIUM phosphate from dihydrogen phosphate precursor exhibited the highest catalytic activity with the methanol conversion of 96. 76%, dimethyl ether selectivity of 96. 8%, and dimethyl ether yield of 93. 67%, whereas the modified sodium montmorillonite-ZIRCONIUM phosphate from diammonium hydrogen phosphate showed good stability towards methanol conversion.

Aim: The aim of this in vitro study was to evaluate imaging artifacts induced by titanium, ZIRCONIUM, and titanium-ZIRCONIUM abutments in computed tomography (CT), cone-beam computed tomography (CBCT), and magnetic resonance imaging (MRI) modalities. Methods: A 4×8-mm titanium fixture was inserted in a dry human mandible. Titanium, ZIRCONIUM, and titanium-ZIRCONIUM abutments measuring 10. 5 mm in height were located on the fixture one by one. Each abutment was scanned four times by each imaging modality. The gray value of the images was evaluated in four determined regions adjacent to distal, mesial, buccal, and lingual aspects of the implant as the region of interest (ROI) by two observers using the Image J software. Gray value differences (Δ GVs) between the control (i. e., fixture without abutment) and case (i. e., fixture and each type of abutment) images were calculated. Data analysis was performed by the analysis of variance and post hoc tests. Results: In the CBCT, Δ GV was significantly higher in ZIRCONIUM-titanium images, compared with that in images with titanium abutments (P<0. 05). In the distal, mesial, and buccal aspects of ROI in CT, the Δ GV was higher in ZIRCONIUM images, compared with titanium abutments. In the MRI, Δ GV for ZIRCONIUM was lower than those for titanium-ZIRCONIUM and titanium samples, respectively. Furthermore, no significant differences in Δ GV were seen between T1 and T2 protocols, for all samples. Conclusion: In MRI, image artifacts are the least around ZIRCONIUM abutments, while in CT and CBCT, titanium abutments produced the least amount of artifacts.