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Graphical abstract, Aflatoxins and ochratoxin A occur frequently in grains and are associated with carcinogenic, and nephrotoxic properties. Therefore, the aim of this study was to determine the level of aflatoxins and ochratoxin A contamination in wheat samples obtained from different Egyptian governorates and to assess the effect of gamma irradiation on AFB1 in spiked wheat samples, as well as to evaluate the estimated daily intake and hazard index. Thirty-six wheat grain samples purchased from different sale points were analyzed by High-Performance Liquid Chromatography. Data revealed that 33.33 % of the wheat grain samples were contaminated by aflatoxin B1, whereas only 16.66 % of the wheat samples were above the maximum limits (2 μg/kg) set by the European Commission. Ochratoxin A was only detected in two wheat grain samples, and the results were considered below the maximum limit (5 μg/kg) set by the European Commission. On studying the effect of gamma irradiation on wheat samples spiked by aflatoxin B1 (20 μg/kg), results revealed that aflatoxin B1 was reduced to 1.22 and 0.94 μg/kg for samples gamma-irradiated at a dose of 10 and 20 KGy respectively. Estimated daily intake of ochratoxin A in wheat samples was found to be higher than that of the tolerable daily intake; however, hazard index values were below one, thus demonstrating no threat to human health.

Glasses of the compositions (100 − x)B2O3-(x / 2)Bi2O3–(x / 2)Fe2O3 with x = 50, 60 and 70 (in mol%) were prepared. The glassy phase of the samples was established by X-ray diffraction (XRD) and Differential thermal analysis (DTA) studies. The formation of the BiFeO3 phase inside the glass matrix (glass-ceramic) by the heat treatment of the sample at x = 60 was identified by XRD, DTA and Fourier transform infrared (FTIR) studies. FTIR results revealed that the glass samples are composed of BO3, BO4, BiO3, BiO6, FeO4 and FeO6 basic structural units. The trends of the glass transition temperature (Tg), density (ρ), molar volume (Vm), oxygen packing fraction (OPD) and theoretical optical basicity (Ʌth) were discussed in terms of the structural modifications that take place in the glass matrix. The variation of the dielectric constant (ɛr), dielectric loss (tan δ) and the ac conductivity of the glass samples cannot be explained on the basis of the distance between iron ions (Ri) only but on the space charge polarization. The dielectric properties of the glass-ceramic were affected by the presence of BiFeO3 phase inside the glass matrix.

Glasses with compositions (100-x) Li 2 B 4 O 7 -x Nb 2 O 5 doped 1 mol% Pr 6 O 11 (where x = 15, 25 and 35 mol%) were prepared. The glass nature of the present samples was established by X-ray diffraction (XRD) which is confirmed by differential thermal analysis (DTA) study. The infrared absorption spectra indicate that the structural units of the present samples are made up of BO 3 , BO 4, NbO 4 and NbO 6 . From the intensities of some optical absorption bands, Judd-Ofelt parameters Ω λ (λ = 2, 4, 6) have been evaluated. The variations in some physical properties such as the density (ρ), molar volume (V M ), optical band gap (E g ) and Urbach energy (E 0 ) have correlated with structural changes in the glass samples. Measurements of the dielectric constant, dielectric loss and ac conductivity as a function of frequency (120 Hz − 100 kHz) and temperature (310–670 K) have also reported.

This work aims to study the influence of gamma irradiation on some borophosphate glasses doped with PbO. Investigation of the structural changes and the optical properties of the studied glass network after successive gamma irradiation with doses of 500 Gy, 1 kGy, 2 kGy, and 5 kGy were done by UV–VIS and ATR-FTIR spectrometers, respectively. FTIR measurements confirmed that BO4 groups decrease and BO3 groups increase with the increase of γ-irradiation. UV–VIS absorption increased slightly with irradiation. The measurements of hardness before and after γ irradiation revealed that the hardness rose with the adding of PbO to glass. This model based on self-repairing for the structure-defects resulted from irradiation which not only creates defects but also induces reversible recovery of the defects. The outcomes reflected that the gamma-ray irradiation has a small influence on the network structure of the prepared glass. Consequently, it can be used in various applications as the nuclear fields.

The conventional melt-quenching technique has been used for preparing a new glass system having the formula 20B2O3: 10Li2O: (70-x)P2O5: xPbO where 5 ≤ x ≤ 30 mol%. The non-crystalline state of the studied samples has been proven by XRD. Investigation of the optical properties and the structural changes of the studied glass network were done by UV-VIS and ATR-FTIR spectrometers, respectively. The obtained optical band gap and refractive index helped to obtain important factors as polarizability and optical basicity. γ-ray shielding parameters including coefficients of linear attenuation and mass attenuation, half-value layer and mean free path were measured experimentally at different γ energies and matched with the theoretical calculations obtained using the mixture principle of WinXCom software. A worthy matching was obtained between the experimental and theoretical values. The outcomes reflected that the adding of PbO significantly improve the potential applications as optoelectronics and enhance the properties of γ-ray shielding in specific energy ranges.

Glass sample with composition Li1.3Nb0.3V1.7(PO4)3 was prepared by quenched melt technique. Double heat treatments performed for different time intervals (12, 18, 24 and 30 h) to obtain glass ceramics with different nanoscale grain sizes. The glassy nature was confirmed from the glass transition temperature using differential thermal analysis (DTA) for the as quenched sample. In addition, the X-ray diffraction (XRD) patterns confirmed the glass nature for the as quenched sample. After heat treatment (HT) the structure of all samples was characterized by XRD. Ionic conductivity and impedance measurements of the derived glass ceramics were systematically investigated. It is observed that the electrical conductivity is enhanced by 103 times for the heat treated glass sample of 24 h, whereas with further increase of HT time up to 30 h, the conductivity started to decrease. Therefore, the phase observed in the 24 h HT is found more suitable to be used as a cathode material in solid batteries compared to its vitreous counterpart.

Homogeneous (50P2O5–(30 − x)PbO–20NaF–xWO3 where x = 0.0, 5, 10 and 15 mol%) glasses were synthesized using a melt-quenching method. The short range structures of the phosphate samples were examined by Fourier transform infrared spectroscopy. The infrared spectral studies have pointed out the existence of conventional PO4, WO4 and WO6 structural units in the glass network, the number of WO4 tetrahedra decreases as WO3 concentration increases. The optical transmittance and reflectance spectrum of the glasses have been recorded in the wavelength range of 190–1100 nm. The values of the optical band gap Eop for all types of electronic transitions and refractive index have been determined and discussed. The real and imaginary parts e1 and e2 of the dielectric constant have been determined. The type of electronic transitions in the present glass system is indirectly allowed and the high values for the refractive index and dispersion are recorded due to the high polarizability of tungsten ions. The results of refractive indices as determined reveal the homogeneity of samples and were found to depend on the glass composition. The electrical properties of the glasses were investigated by ac conductivity from 0.12 to 100 kHz for temperatures ranging from room temperature to 600 K. The study of dielectric properties suggested increase in the insulating character of the glass system with increase in the content of WO3. The ac conductivity in the high temperature region seems to be connected mainly with the polarons involved in the process of transfer from W4+ to W5+ ions.

Transparent glass nanocomposite in the pseudo binary system (100 − x) Li2B4O7–xBaTiO3 with x = 0 and 60 (in mol%) were prepared. Amorphous and glassy characteristics of the as-prepared samples were established via X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC) respectively. The precipitated BaTiO3 nanocrystal phase embedded in the glass sample at x = 60 mol% was identified by transmission electron microscopic (TEM). The optical transmission bands at 598 and 660 nm were assigned to Ti3+ ions in tetragonal distorted octahedral sites. The precipitated Li2B4O7, BaTi(BO3)2 and BaTiO3 nanocrystallites phases with heat-treatment at 923 K for 6 h (HT923) in glass–ceramic were identified by XRD, TEM and infrared absorption spectroscopy. The as-prepared at x = 60 mol% and the HT923 samples exhibit broad dielectric anomalies in the vicinity of the ferroelectric-to-paraelectric transition temperature. The results demonstrate that the method presented may be an effective way to fabricate ferroelectric host and development of multifunctional ferroelectrics.

Glasses in the system (65 − x )Bi 2 O 3 –15Li 2 O–20GeO 2 – x WO 3 (where x = 2, 5 and 10 mol%) were prepared by normal melt quenching method. The change in density and molar volume in these glasses indicates the effect of WO 3 on the glass structure. Fourier transform infrared (FT-IR) spectra show that these glasses are made up of GeO 4 , GeO 6 , BiO 6 , BiO 3 , WO 4 and WO 6 basic structural units. The structural units of BiO 6 , GeO 6 and WO 6 increase with the increasing of WO 3 content. The optical constants of these glasses are determined over a spectral range, providing the complex dielectric constant to be calculated. Higher values for the refractive index and dispersion are recorded due to the high polarizability of bismuth and tungsten ions. The values of the optical band gap E g for all types of electronic transitions and refractive index have been determined and discussed. The dc conductivity measured in the temperature range 423–623 K obeys Arrhenius law. The dielectric constant ( ɛ ′), dielectric loss (tan δ ) and ac conductivity over a wide range of frequency and temperature, of the glasses were investigated.

Transparent glass-nanocomposite sample [50Li2B4O7–50(SrO–Bi2O3–Nb2O5)] (mol %) was prepared by a conventional melt-quenching technique. Fluorite (Bi3NbO7) and SrBi2Nb2O9 (SBN) was produced by heat-treating the as-prepared sample at 773 K for 6 h (HT773). The nanocrystallites of fluorite and SBN phases in the Li2B4O7 glass matrix were established by differential thermal analysis (DTA) which is confirmed by X-ray powder diffraction (XRD), infrared spectroscopy and transmission electron microscopic (TEM) studies. The influence of heat-treating the as-prepared sample on the optical properties (transmission, optical band gap and Urbach energy) has been investigated. Properties such as dielectric constant and dielectric loss as a function of frequency (120 Hz –100 k Hz) and temperature (300–829 K) are reported.

Glasses having compositions 40Bi 2 O 3 –20GeO 2 –(40− x )PbO– x MoO 3 (where x = 3, 6, 9, 12 and 15 mol%) were prepared by normal melt quenching technique. The density ( d ) decreases gradually with the increase of the MoO 3 content in such glasses. This may be due to the lower molecular weight MoO 3 is substituted by a higher molecular weight PbO. The dc conductivity decreases while the activation energy increases with the increase of the MoO 3 content. The dc conductivity in the present glasses is electronic depends strongly upon the average distance, R , between the Mo ions. Analysis of the electrical properties has been made in the light of small polaron hopping model. The parameters obtained from the fits of the experimental data to this model are reasonable and consistent with glass composition. The conduction is attributed to non-adiabatic hopping of small polaron. Dielectric properties (constant e , loss tan δ , ac conductivity σ ac , over a range of frequency 0.12–100 kHz and temperature 325–650 K and frequency exponent s ) of these glasses have been studied.

(75 − x)TeO2–15PbCl2–xMoO3–10ZrO2 doped with 5 mol% Er2O3, where x = 2.5, 5, 7.5 and 10 mol%, glasses were investigated by Raman spectroscopy, dc conductivity, optical transmittance spectra and density were measured. Mo O bonds are present in the entire glass composition. The glasses contain TeO4 trigonal bipyramids, TeO3+1 polyhedra and MoO6 octahedra as basic structural units. Glasses having low MoO3 content contain MoO6 octahedra having two Mo O bonds. As MoO3 content increases, the fraction of Mo O bonds to Mo6+ decreases. The dc conductivity increases with increase in MoO3 content, and the activation energy decreases with increase in MoO3 content. The optical band gap (Eopt) and Urbach energy (Er) were determined from the optical transmittance spectra of the polished samples recorded in the spectral range from 190 to 1100 nm at room temperature (RT). Variation in these optical parameters has also been associated with the structural changes occurring in these glasses with increase in MoO3 content, and the present glasses behave as indirect gap semiconductors.

The affect of sulphur on the structural properties of iron sodium diborate glasses having the composition {(100− x )Na 2 B 4 O 7 + x Fe 2 O 3 }+ y S, where x = 0.05 , 0.15 and 0.25 mol% and Y = 0 , 2.5 and 5 wt% was studied by infrared, Mossbauer spectroscopy and magnetic susceptibility measurements. It was found that, for samples having 5 mol% Fe 2 O 3 and free from sulphur, the iron ions are present in both Fe 2+ and Fe 3+ states and also 92% of the total iron enters the glass network as a glass former. The ratio of Fe 3+ /Fe 2+ increases with increasing the iron content for sulphur-free samples and others containing sulphur. This ratio also decreases with increasing the sulphur content. The magnetic susceptibility was found to decrease with increasing the sulphur content. Also, the increase of Fe 2 O 3 content led to a less symmetrical environment of Fe 3+ ions and vice versa for the Fe 2+ environment.