The Effect of Nano-SiO2 on the Structural, Electrical and Magnetic Properties of SiO2-LiFe5O8 Glass–ceramics Prepared by Sol Gel Auto-combustion Processing

The glass–ceramic with the composition x(LiFe5O8)/(100 – x) SiO2 (x = 20, 30, 40, 50, 100 wt. % ) were prepared by sol gel auto-combustion method. The influence of the SiO2 ratio in the glass-ceramics strucure prepared was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Crystalline phases (LiFe5O8, SiO2, Fe2O3) were observed by X-ray powder diffraction in the glasses annealed at 800°C for 2h. The crystallite size was found to increase from 27.29 nm (x = 20%) to 91.48 nm(x = 100 %). The microstructure of the formed powders was SiO2 ratio dependent. Increasing the SiO2 ratio was found to inhibit the grain growth of the formed ferrite. The electrical conductivity of glass-ceramics samples were raised with increasing the concentration of SiO2 ratio as the result of increasing the hopping of electrons between Fe2+ and Fe3+ ions. The magnetic characteristics of the prepared glass ceramics were performed using a vibrating sample magnetometer in function of the magnetic field. The samples heat -treated at 800°C for 2h present a ferrimagnetic behavior. Alongside, the formed crystalline silicate lithium ferrite had good magnetic properties. High saturation magnetization (51.9 emu/g) was attained the formed ferrite sample of x = 100 % ratio annealed at 800°C for 2h

The Effect of Nano-SiO2 on the Structural, Electrical and Magnetic Properties of SiO2-LiFe5O8 Glass–ceramics Prepared by Sol Gel Auto-combustion Processing

The glass–ceramic with the composition x(LiFe5O8)/(100 – x) SiO2 (x = 20, 30, 40, 50, 100 wt. % ) were prepared by sol gel auto-combustion method. The influence of the SiO2 ratio in the glass-ceramics strucure prepared was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Crystalline phases (LiFe5O8, SiO2, Fe2O3) were observed by X-ray powder diffraction in the glasses annealed at 800°C for 2h. The crystallite size was found to increase from 27.29 nm (x = 20%) to 91.48 nm(x = 100 %). The microstructure of the formed powders was SiO2 ratio dependent. Increasing the SiO2 ratio was found to inhibit the grain growth of the formed ferrite. The electrical conductivity of glass-ceramics samples were raised with increasing the concentration of SiO2 ratio as the result of increasing the hopping of electrons between Fe2+ and Fe3+ ions. The magnetic characteristics of the prepared glass ceramics were performed using a vibrating sample magnetometer in function of the magnetic field. The samples heat -treated at 800°C for 2h present a ferrimagnetic behavior. Alongside, the formed crystalline silicate lithium ferrite had good magnetic properties. High saturation magnetization (51.9 emu/g) was attained the formed ferrite sample of x = 100 % ratio annealed at 800°C for 2h

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

Monosodium glutamate versus diet induced obesity in pregnant rats and their offspring

Background: We aim at determining the role of monosodium glutamate (MSG) compared with high caloric chow (HCC) in development of obesity in pregnant rats and their offspring. Methods: Ninety pregnant rats were divided into 3 groups, control, MSG and HCC fed. We determined energy intake, body weight (BW), abdominal fat, fat to body weight ratio, serum glucose, insulin, leptin, lipid profile, ob and leptin receptor-b gene expressions in pregnant rats and ob and leptin receptor-b gene expressions, serum insulin, glucose, leptin, triacylglycerides (TAG), total lipids (TL) and BW in offspring. Results: Although daily energy intake and BW of MSG treated rats were lower than those of HCC fed rats, their abdominal fat and fat body weight ratio were higher. MSG or HCC increased Ob gene expression, leptin, insulin, LDL, cholesterol, total lipids (TL), glucose and decreased leptin receptor-b gene expression. In offspring of MSG treated rats, BW, serum glucose, insulin, leptin, TAG, TL and Ob gene expression increased and leptin receptor-b gene expression decreased whereas in offspring of HCC fed rats, serum insulin, leptin, Ob and leptin receptor-b gene expression increased but serum glucose, TAG, TL or BW did not change. Conclusion: We conclude that in pregnant rats, MSG, in spite of mild hypophagia, caused severe increase in fat body weight ratio, via leptin resistance, whereas, HCC increased BW and fat body weight ratio, due to hyperphagia with consequent leptin resistance. Moreover, maternal obesity in pregnancy, caused by MSG, has greater impact on offspring metabolism and BW than that induced by HCC