Evaluation of hafnium oxide nanoparticles imaging characteristics as a contrast agent in X-ray computed tomography.

This research aimed to compare the quantitative imaging attributes of synthesized hafnium oxide nanoparticles (NPs) derived from UiO-66-NH2(Hf) and two gadolinium- and iodine-based clinical contrast agents (CAs) using cylindrical phantom. Aqueous solutions of the studied CAs, containing 2.5, 5, and 10 mg/mL of HfO2NPs, gadolinium, and iodine, were prepared. Constructed within a cylindrical phantom, 15 cc small tubes were filled with CAs. Maintaining constant mAs, the phantom underwent scanning at tube voltage variations from 80 to 140 kVp. The CT numbers were quantified in Hounsfield units (HU), and the contrast-to-noise ratios (CNR) were calculated within delineated regions of interest (ROI) for all CAs. The HfO2NPs at 140 kVp and concentration of 2.5 mg/ml exhibited 2.3- and 1.3-times higher CT numbers than iodine and gadolinium, respectively. Notably, gadolinium consistently displayed higher CT numbers than iodine across all exposure techniques and concentrations. At the highest tube potential, the maximum amount of the CAs CT numbers was attained, and at 140 kVp and concentration of 2.5 mg/ml of HfO2NPs the CNR surpassed iodine by 114%, and gadolinium by 30%, respectively. HfO2NPs, as a contrast agent, demonstrated superior image quality in terms of contrast and noise in comparison to iodine- and gadolinium-based contrast media, particularly at higher energies of X-ray in computed tomography. Thus, its utilization is highly recommended in CT.

Synthesis, characterization and application of a zirconium-based MOF-808 functionalized with isonicotinic acid for fast and efficient solid phase extraction of uranium(VI) from wastewater prior to its spectrophotometric determination.

BACKGROUND: A zirconium-based metal-organic framework (Zr-MOF), named MOF-808, was synthesized and fully characterized by solvo-thermal method and functionalized by isonicotinic acid and employed as an efficient adsorbent for selective extraction and preconcentration of uranyl ions from water and waste water samples in a batch solid phase extraction. RESULTS: Parameters affecting extraction such as volume and pH of the sample solution, the amount of sorbent, type and volume of eluting solvent, and adsorption and desorption times were investigated and optimized. Under the optimized conditions, high extraction efficiency was observed with a limit of detection of 0.9 µg L- 1 for uranyl ions and relative standard deviations were found to be better than 2.1% in the range of 0.07-1000 µg L- 1. CONCLUSIONS: These results indicated that the above procedure is fast, inexpensive, effective, reliable, applicable and organic solvent-free and showed the highly performance and stability of the Zr-MOF in SPE based analytical techniques.

Prevalence of Febrile Seizures in Children in Zahedan, South East of Iran.

OBJECTIVES: Febrile seizure is the most common seizure disorder in childhood and a common cause of hospitalization in hospitals. We aimed to investigate the prevalence of febrile seizures in children in Zahedan, south-east of Iran. MATERIALS & METHODS: In this cross-sectional study, 600 children under 7 yr were examined for positive history of febrile seizure in 2014. The cluster sampling method was used, information was collected using a questionnaire, and data were expressed using descriptive- analytical tests. RESULTS: The mean age of the children was 2.7±1.8 year. The sample consisted of 290 (48.3%) boys and 310 (51.7%) girls. Of the 600 children studied, 21 experienced febrile seizure and the incidence of febrile seizures was 3.5%. No significant difference was observed in terms of age or gender. Among the patients with history of febrile seizure, 2 (9.5%) had a positive family history of seizure. The age at the first febrile seizure was under one year in 13 patients (61.9%) and over one year in 8 patients (38.1%). CONCLUSION: Results indicated a moderate incidence of febrile seizure in the studied population. No significant difference was observed in terms of age or gender.