Nanocrystalline barium titanate (BTO3) powders annealed at 1050 • C for 4 h, were synthesized using the sol-gel method and the effects of Sn 4+ /Er 3+ co-doping (BTSO3:2Er) on microstructure and dielectric properties of BTO3 powders, were investigated. The crystalline structure, microstructure, molecular structure, and dielectric properties were investigated using X-ray powder diffraction, field emission scanning electron microscope, with energy dispersive X-ray analysis, the Fourier transform infra-red spectroscopy, and dielectric spectrometer. X-ray powder diffraction analysis confirmed the formation of both BTO3 and BTSO3:2Er in a single tetragonal phase. For BTSO3:2Er sample, the particle size decreased from 64 for pure BTO3 to 57.11 nm for BTSO3:2Er, inhibiting grain growth upon co-doping with Sn 4+ /Er 3+ ions. Further, according to field emission scanning electron microscope observations, the Fourier transform infra-red spectroscopy analysis showed a new band assigned to M-O. Correspondingly, BTSO3:2Er showed an anomaly relaxation peak whose maximum was positioned at temperature value (174 • C) higher than the Curie temperature (TC) according to permittivity measurements. Its TC shifted from 125 to 103 • C and permittivity considerably increased to become ten times greater than that of pure BTO3, revealing enhancements of dielectric properties upon doping with Sn 4+ /Er 3+ ions. Also, AC conductivity for BTSO3:2Er sample considerably increased due to the formation of excess oxygen vacancies.

The motivation of this work was to improve the dielectric properties of nano-structure BaTiO 3 prepared in powder form, using a modified sol-gel method and calcinated in the air at different calcination temperatures between 350 and 1050 °C. For that, we choose to measure the dielectric properties over the high frequency range (10 6 -10 8 Hz) at room temperature (RT), which makes it the candidate for high-frequency ultrasonic and energy storage applications. The dielectric properties give remarkable results obtained maybe for the first time for this compound at the mentioned frequency range. Both the dielectric permittivity and AC conductivity were found to increase with the calcination temperature due to an increase in the crystallite size. Particularly, it has been reported that sample calcinated at 1050 °C shows high permittivity values. The effect of calcination temperature on the morphology, structure, and dielectric properties of the prepared BaTiO 3 nano-powdered was investigated. Transmission electron microscope (TEM) confirmed the nano-crystalline form of prepared samples. X-ray powder diffraction (XRD) results revealed a pure tetragonal phase between 1000 °C and 1050 °C. However, more than one phase was detected at lower temperatures. Furthermore, Raman spectra showed that the tetragonal peaks at 306 and 715 cm −1 , increase with the increase of the calcination temperature. Fourier transformation infrared spectroscopy (FTIR) showed that the crystallinity improved, accompanied with a gradual disappearance of carbonates by increasing calcination temperature.

Background: Hearing loss (HL) is a heterogeneous condition that causes partial or complete hearing impairment. Hundreds of variants in >60 genes have been reported to be associated with Hereditary HL (HHL), variants of the GJB2 gene are the most common cause of congenital SNHL, with >100 variants reported.The HHL prevalence is thought to be high in the Arab population; however, the genetic epidemiology of HHL among Emirati populations is understudied.Aims: To shed light on the mutational spectrum of NSHL in Emirati patients seen in the genetic clinic over 10 years and to capture founder mutation(s) if any were identified. Methods: Retrospective chart review of all Emirati patients assessed by clinical geneticists due to NSHL during the period between January 2010 to December 2020. Genetic tests were done based on clinical phenotypes of the patient and family history including targeted mutation testing, next-generation sequencing, or whole-exome sequencing (solo or trio). The authors did literature reviews using PubMed for all previously reported articles related to NSHL genes from UAE.Results: A total of 162 patients with HL, were evaluated during the period between January 2010 to December 2020. There were 82 patients with NSHL, and only 72 patients who completed the genetic evaluations were included in this retrospective study. Among the studied group, 42 (51.2%) were males and 40 (48.78%) were females. The youngest patient was 2 years old and the oldest patient was 50 years old. Consanguinity was documented in 76 patients (92.68%). A total of 14 mutations reported here are novel (23/72 i.e., 31.9%). Twelve missense mutations, 6 nonsense mutations, 6 frameshift mutations, 2 in-frame deletion mutations, and 1 splice site mutation was found. Variants in the GJB2 gene are the most commonly identified cause of NSHL, with c.35delG being the most followed by c.506G > A. The second commonly found variant is c.934C > G (p.Arg312Gly) in the CDC14A gene, found in 9 patients. This was followed by variants in OTOF and SLC26A4 genes, found in 8 patients, respectively. Chromosomal microdeletions encompassing genes causing NSHL were found in 3 patients. No mitochondrial How to cite this article: Elsayed, O., & Al-Shamsi, A. (2022). Mutation spectrum of non-syndromic hearing loss in the UAE, a retrospective cohort study and literature review. Molecular Genetics & Genomic Medicine, 10, e2052.

Nano-structure BaTi 0.9 Sn 0.1 O 3 (BTSO) doped with Nd 3+ (BTSO: 5N) and co-doped with Nd 3+ /Yb 3+ ions (BTSO: 5NY), were prepared using the modified sol-gel method in powder form and annealed at 1050 o C in air for 4h. Their structural, morphological, photoluminescence and dielectric properties studies were investigated. The crystallite sizes from XRD and TEM found to be decreased upon doping with Nd 3+ and Nd 3+ /Yb 3+ ions, respectively. FTIR results showed enhancement of crystallinity and absence of carbonates upon increasing Yb 3+ ions. TEM micrographs show that particles have spherical shape with small size within the nano-structure phase. FESEM microphotographs showed a density increase due to replacement of Nd 3+ and Yb 3+ ions at the B-site (Ti 4+ ). From photoluminescence it was obtained that emissivity quenched by increasing Yb 3+ ions concentration as the Nd 3+ act as sensitizer for Yb 3+ . Cuire temperature (T c ) of doped and codoped samples shifted to lower values. Besides, their permittivity and AC conductivity increased in comparison with BTSO.

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