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This study involves the investigation of the double perovskite A2NbTbO6 (A = Ca, Sr, and Ba) using the PBE-GGA approximation under the quantum-based DFT (density functional theory) within the WIEN2k code. The materials A2NbTbO6 (A = Ca, Sr, and Ba) are cubic crystals with space group Fm3m-225 and non-magnetic behavior. The structural, electrical, optical, and thermoelectric characteristics of the given materials have been investigated. Band gap and density of state calculations are used to explain the electronic properties of the materials under study with the PBE-GGA approximation. The results made it abundantly evident that the materials are pure semiconductors with direct band gaps. Complex dielectric function, refractive index ƞ(ω), extinction coefficient K(ω), optical conductivity σ(ω), absorption coefficient α(ω), reflectivity R(ω), and loss parameter L(ω) are analyzed to explain the optical behavior of the materials. Charge carrier concentration (n), electrical conductivity (σ/t), Seebeck coefficient (S), power factor (PF), thermal conductivity (K/t), specific heat capacity (Cv), and magnetic susceptibility (χ) are investigated to find the material's thermal properties which show the ability of materials in green energy (eco-friendly) production devices and good candidates for optoelectronics especially for solar cell. The BoltzTraP code, which is part of the WIEN2k code, is used to calculate these properties. The cubic compounds Ca2NbTbO6, Sr2NbTbO6, and Ba2NbTbO6 have band gaps of 1.93 eV, 1.89 eV, and 1.87 eV, respectively and are direct band gap materials are confirmed from the band gap structures. By these calculations, all the characteristics are examined to produce new materials for sustainable devices and renewable energy applications like solar cells, and optoelectronics. [ABSTRACT FROM AUTHOR]

Purpose The goal of this research is to find out the incidence of any ophthalmic adverse effects associated with sofosbuvir − ribavirin combination therapy in comparison with sofosbuvir − ribavirin − interferon combination therapy in patients having chronic hepatitis C. Patients and methods A prospective nonrandomized comparative study was carried on 80 eyes of 40 patients with a documented diagnosis of chronic hepatitis C referred by the Internal Medicine and Hepatogastroenterology Department. Study group 1 (20 patients; 40 eyes) patients enrolled in the dual-therapy delineation (a 24-week regimen of 400 mg/day sofosbuvir and a 600 mg/day ribavirin) and study group 2 (20 patients; 40 eyes) patients registered in the triple-therapy planning (12-week regimen of sofosbuvir and ribavirin plus 180-µg peginterferon α-2a subcutaneously weekly). All recorded patients were subjected to entire ophthalmic examination before the medicaments strategy inauguration with periodic examination at 3 and 6 months during the treatment plan using Schirmer test and tear film breakup time test. Results Retinopathy has been evidenced at 3 months after treatment onset in 15% of group 2 candidates and receded at 6 months, which dates 3 months after treatment termination, with no cases of retinopathy in group 1 patients; the difference was statistically insignificant. Schirmer test and tear film breakup time results changed significantly over the 6-month study period. In study group 1, values of both tests decreased at 3 months after the start of sofosbuvir antiviral drug therapy and continued to dwindle throughout the period of follow-up. On the contrary, in study group 2, they decreased at 3 months after treatment onset but came to the common standard values 3 months after treatment discontinuation. Conclusion In our research, both study groups show that the drug-induced dry eye effects were in any event reasonably mild and had trivial effect on one’s daily performance. The retinal lesions in our patients were peacefully asymptomatic, as there were no effects on the best corrected visual acuity (BCVA) in all patients throughout the 6-month study period.

Purpose The aim of this work is to study the prevalence of dry eye in type II diabetic patients and to correlate the dry eye with the duration of the diabetes and the level of Glycosylated Hemoglobin (Hb 1 Ac). Patients and methods It is a prospective randomized study in which 100 eyes (50 diabetics, 50 control) with type II diabetes mellitus is included in the study attending in department of ophthalmology Ain Shams University. Dry eye was confirmed by tear film break up time (TBUT) and Schirmer I test. Results Schirmer and tear film BUT values were lower among the uncontrolled diabetic patients. There is highly statistically significant relation between severity of dry eye by Schirmer test with duration of diabetes, hypertension, Debris in tear film, degree of diabetic retinopathy, Glycosylated Hemoglobin (HbA1C), with P value 0.003, 0.044, 0.000, 0.000, 0.000 respectively. There is highly statistically significant relation between severity of dry eye by BUT test with duration of DM, HTN, Debris in tear film, DR, HbA1C, with P value 0.002, 0.032, 0.000, 0.001, 0.000 respectively. Conclusion Diabetic patients are more prone to suffering from dry eye than normal subjects. These abnormalities can result in severe complications. Early examination of the diabetic patients for the detection of the ocular surface disorders is indicated.

At high pressure, the pressure dependencies of the structural, electronic, optical, and thermoelectric properties of Fe 2 HfSi Heusler were calculated using the FP-LAPW method within the framework of the density functional theory. The calculations were carried out using the modified Becke-Johnson (mBJ) scheme. Our calculations showed that the Born mechanical stability criteria confirmed the mechanical stability in the cubic phase. Further, through Poisson and Pugh's ratios critical limits, the findings of the ductile strength were computed. At a pressure of 0 GPa, the indirect nature of the material may be deduced from the electronic band structures of Fe 2 HfSi as well as the estimations for its density of states. Under pressure, the real and imaginary dielectric function responses, optical conductivity, absorption coefficient, energy loss function, refractive index, reflectivity, and extinction coefficient were computed in the 0-12 eV range. Using semi-classical Boltzmann theory, a thermal response is also studied. As the pressure rises, the Seebeck coefficient decreases, while the electrical conductivity rises. The figure of merit ( ZT ) and Seebeck coefficients were determined at temperatures of 300 K, 600 K, 900 K, and 1200 K in order to better understand the thermoelectric properties of a material at these different temperatures. Despite the fact that the ideal Seebeck coefficient for Fe 2 HfSi was discovered at 300 K and was determined to be superior to that reported previously. Materials with a thermoelectric reaction has been shown to be suitable for reusing waste heat in systems. As a result, Fe 2 HfSi functional material may aid in the development of new energy harvesting and optoelectronic technologies., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)